Metrics of cellular and vascular infiltration of human acellular dermal matrix in ventral hernia repairs.

PubMed

Campbell, Kristin Turza; Burns, Nadja K; Ensor, Joe; Butler, Charles E

2012-04-01

Human acellular dermal matrix is used for ventral hernia repair, as it resists infection and remodels by means of surrounding tissue. However, the tissue source and impact of basement membrane on cell and vessel infiltration have not been determined. The authors hypothesized that musculofascia would be the primary tissue source of cells and vessels infiltrating into human acellular dermal matrix and that the basement membrane would inhibit infiltration. Fifty-six guinea pigs underwent inlay human acellular dermal matrix ventral hernia repair with the basement membrane oriented toward or away from the peritoneum. At postoperative weeks 1, 2, or 4, repair sites were completely excised. Histologic and immunohistochemical analyses were performed to quantify cell and vessel density within repair-site zones, including interface (lateral, beneath musculofascia) and center (beneath subcutaneous fat) zones. Cell and vessel quantities were compared as functions of zone, basement membrane orientation, and time. Cellular and vascular infiltration increased over time universally. The interface demonstrated greater mean cell density than the center (weeks 1 and 2, p = 0.01 and p < 0.0001, respectively). Cell density was greater with the basement membrane oriented toward the peritoneum at week 4 (p = 0.02). The interface zone had greater mean vessel density than the center zone at week 4 (p < 0.0001). Orienting the basement membrane toward the peritoneum increased vessel density at week 4 (p = 0.0004). Cellular and vascular infiltration into human acellular dermal matrix for ventral hernia repairs was greater from musculofascia than from subcutaneous fat, and the basement membrane inhibited cellular and vascular infiltration. Human acellular dermal matrix should be placed adjacent to the best vascularizing tissue to improve fibrovascular incorporation.

Rapid Anastomosis of Endothelial Progenitor Cell–Derived Vessels with Host Vasculature Is Promoted by a High Density of Cotransplanted Fibroblasts

PubMed Central

Chen, Xiaofang; Aledia, Anna S.; Popson, Stephanie A.; Him, Linda; Hughes, Christopher C.W.

2010-01-01

To ensure survival of engineered implantable tissues thicker than approximately 2–3 mm, convection of nutrients and waste products to enhance the rate of transport will be required. Creating a network of vessels in vitro, before implantation (prevascularization), is one potential strategy to achieve this aim. In this study, we developed three-dimensional engineered vessel networks in vitro by coculture of endothelial cells (ECs) and fibroblasts in a fibrin gel for 7 days. Vessels formed by cord blood endothelial progenitor cell–derived ECs (EPC-ECs) in the presence of a high density of fibroblasts created an interconnected tubular network within 4 days, compared with 5–7 days in the presence of a low density of fibroblasts. Vessels derived from human umbilical vein ECs (HUVECs) in vitro showed similar kinetics. Implantation of the prevascularized tissues into immune-compromised mice, however, revealed a dramatic difference in the ability of EPC-ECs and HUVECs to form anastomoses with the host vasculature. Vascular beds derived from EPC-ECs were perfused within 1 day of implantation, whereas no HUVEC vessels were perfused at day 1. Further, while almost 90% of EPC-EC–derived vascular beds were perfused at day 3, only one-third of HUVEC-derived vascular beds were perfused. In both cases, a high density of fibroblasts accelerated anastomosis by 2–3 days. We conclude that both EPC-ECs and a high density of fibroblasts significantly accelerate the rate of functional anastomosis, and that prevascularizing an engineered tissue may be an effective strategy to enhance convective transport of nutrients in vivo. PMID:19737050

Linking Retinal Microvasculature Features With Severity of Diabetic Retinopathy Using Optical Coherence Tomography Angiography.

PubMed

Bhanushali, Devanshi; Anegondi, Neha; Gadde, Santosh G K; Srinivasan, Priya; Chidambara, Lavanya; Yadav, Naresh Kumar; Sinha Roy, Abhijit

2016-07-01

To correlate retinal vascular features with severity and systemic indicators of diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA). A total of 209 eyes of 122 type 2 diabetes mellitus patients with DR and 60 eyes of 31 normal Indian subjects underwent OCTA imaging. The diabetic retinopathy patients were graded as having either nonproliferative diabetic retinopathy (NPDR: mild, moderate, and severe NPDR using Early Treatment Diabetic Retinopathy Study classification) or proliferative diabetic retinopathy (PDR). Local fractal analysis was applied to the superficial and deep retinal OCTA images. Foveal avascular zone area (FAZ in mm2); vessel density (%); spacing between large vessels (%); and spacing between small vessels (%) were analyzed. Sensitivity and specificity of vascular parameters were assessed with receiver operating characteristics (ROC) curve. Normal eyes had a significantly lower FAZ area, higher vessel density, and lower spacing between large and small vessels compared with DR grades (P < 0.001). In the superficial layer, PDR and severe NPDR had higher spacing between large vessels than mild and moderate NPDR (P = 0.04). However, mild NPDR had higher spacing between the small vessels (P < 0.001). Spacing between the large vessels in the superficial retinal layer correlated positively with HbA1c (r = 0.25, P = 0.03); fasting (r = 0.23, P = 0.02); and postprandial (r = 0.26, P = 0.03) blood sugar. The same spacing in the deep retinal vascular plexus had the highest area under the ROC curve (0.99 ± 0.01) and was uniformly elevated in all diabetic eyes (P > 0.05). Spacing between the large vessels in the superficial and deep retinal layers had superior diagnostic performance than overall vessel density.

An immunocytochemical study of the germinal layer vasculature in the developing fetal brain using Ulex europaeus 1 lectin.

PubMed

Gould, S J; Howard, S

1988-10-01

The characteristics of the germinal matrix vasculature were studied in the developing fetal brain using immunocytochemical methods. A preliminary comparative immunocytochemical study was made on six fetal brains to compare endothelial staining by Ulex europaeus I lectin with that of antibody to Factor VIII related antigen. Ulex was found to stain germinal layer vessels better than Factor VIII related antigen. Subsequently, the germinal layers of a further 15 fetal and preterm infant brains ranging from 13 to 35 weeks' gestation were stained with Ulex europaeus I to demonstrate the vasculature. With increasing gestation, there was a gradual increase in vessel density, particularly of capillaries. This was not a uniform process. A plexus of capillaries was prominent immediately beneath the ependyma while the more central parts of the germinal matrix contained fewer, but often larger diameter, vessels. The variation in vessel density which was a feature of the later gestation brains may have implications for local blood flow and may be a factor in haemorrhage at this site.

VEGF165 Stimulates Vessel Density and Vessel Diameter Differently in Angiogenesis and Lymphangiogenesis

NASA Technical Reports Server (NTRS)

Parsons-Wingerter, Patricia; Radhakrishnan, Krishnan; DiCorleto, Paul E.; Leontiev, Dmitry; Anand-Apte, Bela; Albarran, Brian; Farr, Andrew G.

2005-01-01

Vascular endothelial growth factor-165 (VEGF(sub 165)) stimulated angiogenesis in the quail chorioallantoic membrane (CAM) by vessel expansion from the capillary network. However, lymphangiogenesis was stimulated by the filopodial guidance of tip cells located on blind-ended lymphatic sprouts. As quantified by fractal/generational branching analysis using the computer code VESGEN, vascular density increased maximally at low VEGF concentrations, and vascular diameter increased most at high VEGF concentrations. Increased vascular density and diameter were statistically independent events (r(sub s), -0.06). By fluorescence immunohistochemistry of VEGF receptors VEGFR-1 and VEGFR-2, alpha smooth muscle actin ((alpha) SMA) and a vascular/lymphatic marker, VEGF(sub 165) increased the density and diameter of sprouting lymphatic vessels guided by tip cells (accompanied by the dissociation of lymphatics from blood vessels). Isolated migratory cells expressing (alpha)SMA were recruited to blood vessels, whereas isolated cells expressing VEGFR-2 were recruited primarily to lymphatics. In conclusion, VEGF(sub 165) increased lymphatic vessel density by lymphatic sprouting, but increased blood vessel density by vascular expansion from the capillary network.

Imaging Foveal Microvasculature: Optical Coherence Tomography Angiography Versus Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography.

PubMed

Mo, Shelley; Krawitz, Brian; Efstathiadis, Eleni; Geyman, Lawrence; Weitz, Rishard; Chui, Toco Y P; Carroll, Joseph; Dubra, Alfredo; Rosen, Richard B

2016-07-01

To compare the use of optical coherence tomography angiography (OCTA) and adaptive optics scanning light ophthalmoscope fluorescein angiography (AOSLO FA) for characterizing the foveal microvasculature in healthy and vasculopathic eyes. Four healthy controls and 11 vasculopathic patients (4 diabetic retinopathy, 4 retinal vein occlusion, and 3 sickle cell retinopathy) were imaged with OCTA and AOSLO FA. Foveal perfusion maps were semiautomatically skeletonized for quantitative analysis, which included foveal avascular zone (FAZ) metrics (area, perimeter, acircularity index) and vessel density in three concentric annular regions of interest. On each set of OCTA and AOSLO FA images, matching vessel segments were used for lumen diameter measurement. Qualitative image comparisons were performed by visual identification of microaneurysms, vessel loops, leakage, and vessel segments. Adaptive optics scanning light ophthalmoscope FA and OCTA showed no statistically significant differences in FAZ perimeter, acircularity index, and vessel densities. Foveal avascular zone area, however, showed a small but statistically significant difference of 1.8% (P = 0.004). Lumen diameter was significantly larger on OCTA (mean difference 5.7 μm, P < 0.001). Microaneurysms, fine structure of vessel loops, leakage, and some vessel segments were visible on AOSLO FA but not OCTA, while blood vessels obscured by leakage were visible only on OCTA. Optical coherence tomography angiography is comparable to AOSLO FA at imaging the foveal microvasculature except for differences in FAZ area, lumen diameter, and some qualitative features. These results, together with its ease of use, short acquisition time, and avoidance of potentially phototoxic blue light, support OCTA as a tool for monitoring ocular pathology and detecting early disease.

Optical coherence tomography angiography discerns preclinical diabetic retinopathy in eyes of patients with type 2 diabetes without clinical diabetic retinopathy.

PubMed

Cao, Dan; Yang, Dawei; Huang, Zhongning; Zeng, Yunkao; Wang, Jun; Hu, Yunyan; Zhang, Liang

2018-05-01

To investigate changes in retinal vascular plexuses and choriocapillaris in patients with type 2 diabetes mellitus (DM2) without diabetic retinopathy (DR) and healthy controls using optical coherence tomography angiography (OCTA). A total of 71 DM2 and 67 healthy control subjects were included. All subjects underwent OCTA examination (RTVue-XR Avanti; Optovue, Fremont, CA, USA). Average vessel density in superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris, parafoveal vessel density in SCP and DCP, FAZ area (mm 2 ) in SCP, microaneurysms and capillary nonperfusion were taken into analysis. Parafoveal vessel density in both SCP and DCP decreased in the eyes without clinical DR compared to normal controls (p < 0.001). Diabetic patients with no signs of DR also had a significant reduction in average vessel density of SCP, DCP and choriocapillaris (p < 0.001, p < 0.001 and p = 0.006, respectively). No significant difference was found in FAZ area of SCP between DM2 eyes and healthy controls (p = 0.253). The average vessel density of SCP and DCP is not correlated with HbA1c or serum creatinine in DM2 patients. Microaneurysms seen in OCTA but not in fundus examination were found in 8 out of the 71 (11.3%) diabetic eyes, and capillary nonperfusion was noted in 18 of 71 diabetic eyes. We demonstrated that OCTA can identify preclinical DR before the manifestation of clinically apparent retinopathy in diabetic eyes. DM2 patients without DR have SCP, DCP and choriocapillaris impairment. Our results suggested that OCTA might be a promising tool for regular screening of diabetic eyes for DR.

Description of the Marine Traffic inside the Pelagos Sanctuary for Mediterranean Marine Mammals: Key Information for Conservation Policy.

NASA Astrophysics Data System (ADS)

Moulins, A.; D'incà, M.; Rosso, M.; Tepsich, P.; Coomber, F. G.

2016-02-01

The International Sanctuary for the Protection of Mediterranean Marine Mammals was established in order to improve conservation measures where cetaceans are abundant and highly impacted by human pressures. Shipping is one of the main human activity in the Sanctuary with many impacts on the ecosystem but still, it is not well known. This study presents the results of shipping collected during 18 consecutive months by an AIS (Automatic Information System) antenna. More than 3 millions of km were covered by the 6 types of ships: passenger, cargo, tanker, fishing, pleasure and service. The predominant types of the vessel list were cargo (41.8%) and pleasure vessels (31.8%) and over half (62.9%) were classed as commercial vessels (passenger, cargo, tanker). Considering the distance covered, passenger and cargo vessels were the most predominant (with 37% and 38% kilometers respectively) and the commercial vessels contribute with 85% of the total kilometers. Compared to the global scale, the study highlights the importance and predominance of intra-Mediterranean transits made especially by passenger crafts between the Italian and French mainland to the islands of Corsica and Sardinia. The spatial distribution was not uniform and the density was found to be vessel type dependent. Many high densities displayed distinct shipping routes and impacted on different jurisdictional boundaries: a third (32%) of the commercial traffic was recorded outside the territorial waters and on different ecological areas of the sanctuary: the main shipping corridors traverse all ecological regions. Overlapping the shipping density with the different cetacean species distributions, it was possible to evaluate spatial vulnerability of the different species and help to focus Pelagos protection measures on more restricted areas. The vessel speeds were found to be high and dependent on vessel type with specific spatial distributions. This work confirms that passenger vessels, and to some degree the other commercial vessels, travelled faster than other ships but had spatially localized higher speeds within distinct shipping corridors. Considering that ship-whale collision probability increases with vessel speed, this study points out areas of higher vulnerability and the more impacting types of vessels.

Exploration of peripapillary vessel density in highly myopic eyes with peripapillary intrachoroidal cavitation and its relationship with ocular parameters using optical coherence tomography angiography.

PubMed

Chen, Qiuying; He, Jiangnan; Hua, Yihong; Fan, Ying

2017-12-01

Identifying changes of peripapillary vessel density in highly myopic eyes with peripapillary intrachoroidal cavitation by optical coherence tomography angiography. To investigate peripapillary vessel density and its relationship with other ocular parameters in highly myopic eyes with peripapillary intrachoroidal cavitation. Hospital-based, cross-sectional study. Thirty-five highly myopic eyes with peripapillary intrachoroidal cavitation, 46 highly myopic eyes without peripapillary intrachoroidal cavitation and 36 normal eyes were included in this study. All participants underwent optical coherence tomography angiography to image the retinal vasculature in the peripapillary areas, including the radial peripapillary capillaries and optic nerve head layer. Correlations between vessel density and ocular metrics were analysed. Peripapillary vessel density. In highly myopic eyes, vessel density was significantly lower in eyes with peripapillary intrachoroidal cavitation than in those without in peripapillary (P = 0.014, P = 0.037), inferotemporal (P < 0.001, P < 0.001) and superotemporal (P = 0.014, P = 0.009) areas. In the radial peripapillary capillaries layer, vessel density was negatively correlated with peripapillary atrophy area (P = 0.012) and myopic maculopathy (P = 0.002), and in the optic nerve head layer, it was negatively associated with a diagnosis of peripapillary intrachoroidal cavitation (P = 0.012) and myopic maculopathy (P < 0.001). In addition, it was positively correlated with retinal nerve fibre layer thickness in both layers (P < 0.001). Highly myopic eyes with peripapillary intrachoroidal cavitation had lower peripapillary vessel densities, especially in the temporal area, than those without. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

Monitoring system for a liquid-cooled nuclear fission reactor. [PWR

DOEpatents

DeVolpi, A.

1984-07-20

The invention provides improved means for detecting the water levels in various regions of a water-cooled nuclear power reactor, viz., in the downcomer, in the core, in the inlet and outlet plenums, at the head, and elsewhere; and also for detecting the density of the water in these regions. The invention utilizes a plurality of exterior gamma radiation detectors and a collimator technique operable to sense separate regions of the reactor vessel to give respectively, unique signals for these regions, whereby comparative analysis of these signals can be used to advise of the presence and density of cooling water in the vessel.

Endometrial vessel maturation in women exposed to levonorgestrel-releasing intrauterine system for a short or prolonged period of time.

PubMed

Stéphanie, Ravet; Labied, Soraya; Blacher, Silvia; Frankenne, Francis; Munaut, Carine; Fridman, Viviana; Beliard, Aude; Foidart, Jean-Michel; Nisolle, Michelle

2007-12-01

Levonorgestrel-releasing intrauterine system (LNG-IUS), although inserted to reduce heavy menstruation, causes irregular early transient bleeding. The objective of the study was to document quantitative changes in endometrial vessels of short- (< or =3 months) and long-term (> or =12 months) LNG users. The area, density and maturation of endometrial vessels were quantified in 19 endometrial biopsies of women with LNG-IUS and in 10 normally ovulating patients during mid-luteal phase. Vessel maturation was evaluated by double immunostaining using anti-von Willebrand factor (endothelial cell marker) and anti-alpha Smooth Muscle Actin (vascular smooth muscle cells) antibodies. Vessel area, number and density were quantified with a novel computer-assisted image analysis system. Endometrium exposed to LNG-IUS for 1-3 months displayed a 11.5-fold increase in small naked vessel number. The partially mature vessel (alphaSMA partially positive) number increased six times. After long-term LNG-IUS treatment, the immature and partially mature vessel number remained four times higher than in the control group. Vessel area and density also increased dramatically in a time-dependent pattern with LNG-IUS use. Levonorgestrel affects blood vessel number, area, density and maturation in a time-dependent pattern that may explain the early transient increase in breakthrough bleeding with the LNG-IUS.

Optical coherence tomography angiography indicates associations of the retinal vascular network and disease activity in multiple sclerosis.

PubMed

Feucht, Nikolaus; Maier, Mathias; Lepennetier, Gildas; Pettenkofer, Moritz; Wetzlmair, Carmen; Daltrozzo, Tanja; Scherm, Pauline; Zimmer, Claus; Hoshi, Muna-Miriam; Hemmer, Bernhard; Korn, Thomas; Knier, Benjamin

2018-01-01

Patients with multiple sclerosis (MS) and clinically isolated syndrome (CIS) may show alterations of retinal layer architecture as measured by optical coherence tomography. Little is known about changes in the retinal vascular network during MS. To characterize retinal vessel structures in patients with MS and CIS and to test for associations with MS disease activity. In all, 42 patients with MS or CIS and 50 healthy controls underwent retinal optical coherence tomography angiography (OCT-A) with analysis of the superficial and deep vascular plexuses and the choriocapillaries. We tested OCT-A parameters for associations with retinal layer volumes, history of optic neuritis (ON), and the retrospective disease activity. Inner retinal layer volumes correlated positively with the density of both the superficial and deep vascular plexuses. Eyes of MS/CIS patients with a history of ON revealed reduced vessel densities of the superficial and deep vascular plexuses as compared to healthy controls. Higher choriocapillary vessel densities were associated with ongoing inflammatory disease activity during 24 months prior to OCT-A examination in MS and CIS patients. Optic neuritis is associated with rarefaction of the superficial and deep retinal vessels. Alterations of the choriocapillaries might be linked to disease activity in MS.

Comparison of the oral and rectal mucosal and colonic serosal microcirculations of healthy, anesthetized horses.

PubMed

Kieffer, Philip J; Williams, Jarred M; Shepard, Molly K; Giguère, Steeve; Epstein, Kira L

2018-01-01

The objectives of the study were to: i) determine baseline microvascular perfusion indices (MPI) and assess their repeatability in healthy horses under general anesthesia, and ii) compare the MPIs of 3 microvascular beds (oral mucosa, colonic serosa, and rectal mucosa). Healthy adult horses were anesthetized and sidestream dark field microscopy was used to collect video loops of the oral mucosa, rectal mucosa, and colonic serosa under normotensive conditions without cardiovascular support drugs; videos were later analyzed to produce MPIs. Baseline MPI values were determined for each site, which included the total vessel density (TVD), perfused vessel density (PVD), portion perfused vessels (PPV), and microcirculatory flow index (MFI). Differences in MPIs between microvascular beds were not statistically significant. Repeatability of the measurements varied for each MPI. In particular, the site of sampling had a profound effect on the repeatability of the PPV measurements and should be considered in future studies.

Comparison of the oral and rectal mucosal and colonic serosal microcirculations of healthy, anesthetized horses

PubMed Central

Kieffer, Philip J.; Williams, Jarred M.; Shepard, Molly K.; Giguère, Steeve; Epstein, Kira L.

2018-01-01

The objectives of the study were to: i) determine baseline microvascular perfusion indices (MPI) and assess their repeatability in healthy horses under general anesthesia, and ii) compare the MPIs of 3 microvascular beds (oral mucosa, colonic serosa, and rectal mucosa). Healthy adult horses were anesthetized and sidestream dark field microscopy was used to collect video loops of the oral mucosa, rectal mucosa, and colonic serosa under normotensive conditions without cardiovascular support drugs; videos were later analyzed to produce MPIs. Baseline MPI values were determined for each site, which included the total vessel density (TVD), perfused vessel density (PVD), portion perfused vessels (PPV), and microcirculatory flow index (MFI). Differences in MPIs between microvascular beds were not statistically significant. Repeatability of the measurements varied for each MPI. In particular, the site of sampling had a profound effect on the repeatability of the PPV measurements and should be considered in future studies. PMID:29382969

Foveal and Peripapillary Vascular Decrement in Migraine With Aura Demonstrated by Optical Coherence Tomography Angiography

PubMed Central

Chang, Melinda Y.; Phasukkijwatana, Nopasak; Garrity, Sean; Pineles, Stacy L.; Rahimi, Mansour; Sarraf, David; Johnston, Mollie; Charles, Andrew; Arnold, Anthony C.

2017-01-01

Purpose Migraine, particularly with aura, has been associated with ocular and systemic ischemic complications, but there are limited data on the ocular vasculature in migraine. We used optical coherence tomography angiography (OCTA) to assess perfusion of the macula and optic nerve in migraine patients, with (MA) and without (MO) aura, compared to healthy controls (HC). Methods We recruited 15 MA (mean age 42 years), 12 MO (mean age 46 years), and 22 HC (mean age 39 years) participants from neurology and neuro-ophthalmology clinics. Participants underwent optical coherence tomography and 3 × 3 mm OCTA of the macula and optic nerve. Foveal avascular zone area was automatically measured using AngioVue software, and vessel density was calculated as blood vessel length divided by scan area (mm−1) after skeletonization of OCTA images. Results On macular OCTA, MA participants had an enlarged foveal avascular zone area when compared with HC (0.300 ± 0.019 vs. 0.220 ± 0.066 mm2, P = 0.006). In addition, superficial foveal vessel density was decreased in MA participants when compared with MO participants (7.8 ± 0.31 vs. 9.3 ± 0.44, P = 0.04) and HC (7.8 ± 0.31 vs. 9.4 ± 0.21 mm−1, P = 0.002). On optic nerve OCTA, the MA participants had reduced superior peripapillary vessel density when compared with the MO participants (12.0 ± 0.45 vs. 14.0 ± 0.38 mm−1, P = 0.031) and HC (12.0 ± 0.45 vs. 14.1 ± 0.53 mm−1, P = 0.035). There were no significant differences between the MO and HC groups. Conclusions Migraine with, but not without, aura was associated with foveal and peripapillary vascular decrements, which may possibly mediate increased risk of ocular and systemic vascular complications in these patients. OCTA could potentially be useful as a biomarker for migraine with aura. PMID:29059314

Integration of vessel traits, wood density, and height in angiosperm shrubs and trees.

PubMed

Martínez-Cabrera, Hugo I; Schenk, H Jochen; Cevallos-Ferriz, Sergio R S; Jones, Cynthia S

2011-05-01

Trees and shrubs tend to occupy different niches within and across ecosystems; therefore, traits related to their resource use and life history are expected to differ. Here we analyzed how growth form is related to variation in integration among vessel traits, wood density, and height. We also considered the ecological and evolutionary consequences of such differences. In a sample of 200 woody plant species (65 shrubs and 135 trees) from Argentina, Mexico, and the United States, standardized major axis (SMA) regression, correlation analyses, and ANOVA were used to determine whether relationships among traits differed between growth forms. The influence of phylogenetic relationships was examined with a phylogenetic ANOVA and phylogenetically independent contrasts (PICs). A principal component analysis was conducted to determine whether trees and shrubs occupy different portions of multivariate trait space. Wood density did not differ between shrubs and trees, but there were significant differences in vessel diameter, vessel density, theoretical conductivity, and as expected, height. In addition, relationships between vessel traits and wood density differed between growth forms. Trees showed coordination among vessel traits, wood density, and height, but in shrubs, wood density and vessel traits were independent. These results hold when phylogenetic relationships were considered. In the multivariate analyses, these differences translated as significantly different positions in multivariate trait space occupied by shrubs and trees. Differences in trait integration between growth forms suggest that evolution of growth form in some lineages might be associated with the degree of trait interrelation.

Factors influencing intracranial vessel densities on unenhanced computed tomography: differences between hemispheres.

PubMed

Grams, Astrid E; Rehwald, Rafael; Schmittnägel, Charlotte; Schmidt, Thorsten; Tanislav, Christian; Berghoff, Martin; Krombach, Gabriele A; Moritz, Regina; Obert, Martin; Gizewski, Elke R; Glodny, Bernhard

The aim was to identify the factors influencing intracranial vessel density (VD). The Hounsfield units of the dense vessel and the contralateral side were measured in 34 patients with arterial clots, 20 with venous clots, and 196 without clots and correlated with skull thickness, density and dimensions, gender, age, red blood cell count (RBC), hemoglobin (HB), hematocrit (HT), creatinine, and sodium. Positive correlations were found between VD and HT, RBC, HB, creatinine, and occipital bone density. Density differences between the right and left intracranial vessels were more accurate (sensitivity/specificity/accuracy=0.91/0.93/0.93 and 0.75/0.87/0.85, respectively) for detecting clots than VD alone. HT, RBC, and HB are the main factors that correlate with VD. Copyright © 2016 Elsevier Inc. All rights reserved.

Correlation between blood and lymphatic vessel density and results of contrast-enhanced spectral mammography.

PubMed

Luczynska, Elzbieta; Niemiec, Joanna; Ambicka, Aleksandra; Adamczyk, Agnieszka; Walasek, Tomasz; Ryś, Janusz; Sas-Korczyńska, Beata

2015-09-01

Contrast-enhanced spectral mammography (CESM) is a novel technique used for detection of tumour vascularity by imaging the moment in which contrast, delivered to the lesion by blood vessels, leaks out of them, and flows out through lymphatic vessels. In our study, we included 174 women for whom spectral mammography was performed for diagnostic purposes. The relationship between enhancement in CESM and blood vessel density (BVD), lymphatic vessel density (LVD) or the percentage of fields with at least one lymphatic vessel (distribution of podoplanin-positive vessels - DPV) and other related parameters was assessed in 55 cases. BVD, LVD and DPV were assessed immunohistochemically, applying podoplanin and CD31/CD34 as markers of lymphatic and blood vessels, respectively. The sensitivity (in detection of malignant lesions) of CESM was 100%, while its specificity - 39%. We found a significant positive correlation between the intensity of enhancement in CESM and BVD (p = 0.007, r = 0.357) and a negative correlation between the intensity of enhancement in CESM and DPV (p = 0.003, r = -0.390). Lesions with the highest enhancement in CESM showed a high number of blood vessels and a low number of lymphatics. 1) CESM is a method characterized by high sensitivity and acceptable specificity; 2) the correlation between CESM results and blood/lymphatic vessel density confirms its utility in detection of tissue angiogenesis and/or lymphangiogenesis.

Vascular density of superficial esophageal squamous cell carcinoma determined by direct observation of resected specimen using narrow band imaging with magnifying endoscopy.

PubMed

Kikuchi, D; Iizuka, T; Hoteya, S; Nomura, K; Kuribayashi, Y; Toba, T; Tanaka, M; Yamashita, S; Furuhata, T; Matsui, A; Mitani, T; Inoshita, N; Kaise, M

2017-11-01

Observation of the microvasculature using narrow band imaging (NBI) with magnifying endoscopy is useful for diagnosing superficial squamous cell carcinoma. Increased vascular density is indicative of cancer, but not many studies have reported differences between cancerous and noncancerous areas based on an objective comparison. We observed specimens of endoscopic submucosal dissection (ESD) using NBI magnification, and determined the vascular density of cancerous and noncancerous areas. A total of 25 lesions of esophageal squamous cell carcinoma that were dissected en bloc by ESD between July 2013 and December 2013 were subjected to NBI magnification. We constructed a device that holds an endoscope and precisely controls the movement along the vertical axis in order to observe submerged specimens by NBI magnification. NBI image files of both cancerous (pathologically determined invasion depth, m1/2) and surrounding noncancerous areas were created and subjected to vascular density assessment by two endoscopists who were blinded to clinical information. The invasion depth was m1/2 in 20, m3/sm1 in four and sm2 in one esophageal cancer lesion. Mean vascular density was significantly increased in cancerous areas (37.6 ± 16.3 vessels/mm2) compared with noncancerous areas (17.6 ± 10.0 vessels/mm2) (P < 0.05). The correlation coefficients between vascular density determined by two endoscopists were 0.86 and 0.81 in cancerous and noncancerous areas, respectively. Receiver operating curve (ROC) analysis revealed that the area under the curve (AUC) of vascular density was 0.895 (95% CI, 0.804-0.986). For this ROC curve, sensitivity was 78.3% and specificity was 87.0% when the cutoff value of vascular density was 26 vessels/mm2. NBI magnification confirmed significant increases in vascular density in cancerous areas compared with noncancerous areas in esophageal squamous cell carcinoma. The rates of agreement between vascular density values determined by two independent operators were high. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Patterns in hydraulic architecture from roots to branches in six tropical tree species from cacao agroforestry and their relation to wood density and stem growth.

PubMed

Kotowska, Martyna M; Hertel, Dietrich; Rajab, Yasmin Abou; Barus, Henry; Schuldt, Bernhard

2015-01-01

For decades it has been assumed that the largest vessels are generally found in roots and that vessel size and corresponding sapwood area-specific hydraulic conductivity are acropetally decreasing toward the distal twigs. However, recent studies from the perhumid tropics revealed a hump-shaped vessel size distribution. Worldwide tropical perhumid forests are extensively replaced by agroforestry systems often using introduced species of various biogeographical and climatic origins. Nonetheless, it is unknown so far what kind of hydraulic architectural patterns are developed in those agroforestry tree species and which impact this exerts regarding important tree functional traits, such as stem growth, hydraulic efficiency and wood density (WD). We investigated wood anatomical and hydraulic properties of the root, stem and branch wood in Theobroma cacao and five common shade tree species in agroforestry systems on Sulawesi (Indonesia); three of these were strictly perhumid tree species, and the other three tree species are tolerating seasonal drought. The overall goal of our study was to relate these properties to stem growth and other tree functional traits such as foliar nitrogen content and sapwood to leaf area ratio. Our results confirmed a hump-shaped vessel size distribution in nearly all species. Drought-adapted species showed divergent patterns of hydraulic conductivity, vessel density, and relative vessel lumen area between root, stem and branch wood compared to wet forest species. Confirming findings from natural old-growth forests in the same region, WD showed no relationship to specific conductivity. Overall, aboveground growth performance was better predicted by specific hydraulic conductivity than by foliar traits and WD. Our study results suggest that future research on conceptual trade-offs of tree hydraulic architecture should consider biogeographical patterns underlining the importance of anatomical adaptation mechanisms to environment.

How to evaluate the microcirculation: report of a round table conference

PubMed Central

De Backer, Daniel; Hollenberg, Steven; Boerma, Christiaan; Goedhart, Peter; Büchele, Gustavo; Ospina-Tascon, Gustavo; Dobbe, Iwan; Ince, Can

2007-01-01

Introduction Microvascular alterations may play an important role in the development of organ failure in critically ill patients and especially in sepsis. Recent advances in technology have allowed visualization of the microcirculation, but several scoring systems have been used so it is sometimes difficult to compare studies. This paper reports the results of a round table conference that was organized in Amsterdam in November 2006 in order to achieve consensus on image acquisition and analysis. Methods The participants convened to discuss the various aspects of image acquisition and the different scores, and a consensus statement was drafted using the Delphi methodology. Results The participants identified the following five key points for optimal image acquisition: five sites per organ, avoidance of pressure artifacts, elimination of secretions, adequate focus and contrast adjustment, and recording quality. The scores that can be used to describe numerically the microcirculatory images consist of the following: a measure of vessel density (total and perfused vessel density; two indices of perfusion of the vessels (proportion of perfused vessels and microcirculatory flow index); and a heterogeneity index. In addition, this information should be provided for all vessels and for small vessels (mostly capillaries) identified as smaller than 20 μm. Venular perfusion should be reported as a quality control index, because venules should always be perfused in the absence of pressure artifact. It is anticipated that although this information is currently obtained manually, it is likely that image analysis software will ease analysis in the future. Conclusion We proposed that scoring of the microcirculation should include an index of vascular density, assessment of capillary perfusion and a heterogeneity index. PMID:17845716

Image-based 3D modeling study of the influence of vessel density and blood hemoglobin concentration on tumor oxygenation and response to irradiation.

PubMed

Lagerlöf, Jakob H; Kindblom, Jon; Cortez, Eliane; Pietras, Kristian; Bernhardt, Peter

2013-02-01

Hypoxia is one of the most important factors influencing clinical outcome after radiotherapy. Improved knowledge of factors affecting the levels and distribution of oxygen within a tumor is needed. The authors constructed a theoretical 3D model based on histological images to analyze the influence of vessel density and hemoglobin (Hb) concentration on the response to irradiation. The pancreases of a Rip-Tag2 mouse, a model of malignant insulinoma, were excised, cryosectioned, immunostained, and photographed. Vessels were identified by image thresholding and a 3D vessel matrix assembled. The matrix was reduced to functional vessel segments and enlarged by replication. The steady-state oxygen tension field of the tumor was calculated by iteratively employing Green's function method for diffusion and the Michaelis-Menten model for consumption. The impact of vessel density on the radiation response was studied by removing a number of randomly selected vessels. The impact of Hb concentration was studied by independently changing vessel oxygen partial pressure (pO(2)). For each oxygen distribution, the oxygen enhancement ratio (OER) was calculated and the mean absorbed dose at which the tumor control probability (TCP) was 0.99 (D(99)) was determined using the linear-quadratic cell survival model (LQ model). Decreased pO(2) shifted the oxygen distribution to lower values, whereas decreased vessel density caused the distribution to widen and shift to lower values. Combined scenarios caused lower-shifted distributions, emphasising log-normal characteristics. Vessel reduction combined with increased blood pO(2) caused the distribution to widen due to a lack of vessels. The most pronounced radiation effect of increased pO(2) occurred with tumor tissue with 50% of the maximum vessel density used in the simulations. A 51% decrease in D(99), from 123 to 60 Gy, was found between the lowest and highest pO(2) concentrations. Our results indicate that an intermediate vascular density region exists where enhanced blood oxygen concentration may be beneficial for radiation response. The results also suggest that it is possible to distinguish between diffusion-limited and anemic hypoxia from the characteristics of the pO(2) distribution.

Variability in sublingual microvessel density and flow measurements in healthy volunteers.

PubMed

Hubble, Sheena M A; Kyte, Hayley L; Gooding, Kim; Shore, Angela C

2009-02-01

As sublingual microvascular indices are increasingly heralded as new resuscitation end-points, better population data are required to power clinical studies. This paper describes improved methods to quantify sublingual microvessel flow and density in images obtained by sidestream dark field (SDF) technology in healthy volunteers, including vessels under 10 microm in diameter. Measurements of sublingual capillary density and flow were obtained by recording three 15-second images in 20 healthy volunteers over three days. Two independent observers quantified capillary density by using two methods: total vessel length (mm/mm2) and counting (number/mm). Both intraoral and temporal variabilities within subject and observer reproducibilities were determined by using coefficients of variability and reproducibility indices. For small (1-10 microm), medium (11-20 microm), and large (21-50 microm) diameter, mean vessel density with standard deviations (SDs) in volunteers was 21.3(+/- 4.9), 5.2 (+/- 1.2), and 2.7 (+/- 0.9) mm/mm2, respectively. Also, 94.0 +/- 1.4% of small vessels, 94.5 +/- 1.4% of medium vessels, and 94.5+/- 4.0% of large vessels had continuous perfusion. Within subjects, the means of all measurements over three days varied less than 13, 22, and 35% in small, medium, and large vessels, respectively. Interobserver reproducibility was good, especially for capillary (1-10 microm) density and flow measurements. Our methods of microvessel flow and density quantification have low observer variability and confirm the stability of microcirculatory measurements over time. These results facilitate the development of SDF-acquired sublingual microvascular indices as feasible microperfusion markers in shock resuscitation.

Peripapillary and Macular Vessel Density in Glaucoma Patients with Single-Hemifield Visual Field Defect

PubMed Central

Yarmohammadi, Adeleh; Zangwill, Linda M.; Diniz-Filho, Alberto; Saunders, Luke J.; Suh, Min Hee; Wu, Zhichao; Manalastas, Patricia Isabel C.; Akagi, Tadamichi; Medeiros, Felipe A.; Weinreb, Robert N.

2017-01-01

Purpose To compare hemifield differences in the vessel density of the optic nerve head and macula in open-angle glaucoma (OAG) eyes with visual field (VF) defect confined to one hemifield using optical coherence tomography angiography (OCT-A). Design Cross-sectional study. Participants Fifty-eight eyes of 58 glaucoma patients with VF loss confined to a single hemifield, and 28 healthy eyes. Methods Retinal vasculature information was summarized as circumpapillary vessel density (cpVD) and perifoveal vessel density (pfVD). Circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell complex (mGCC) thickness were also calculated using spectral domain OCT. Paired and unpaired t-tests were utilized to evaluate differences between the perimetrically affected and intact hemiretinae and healthy hemiretinae. Linear regression analyses were performed to evaluate the associations between VF measures with vascular and structural measurements. Main Outcome Measures Total and hemispheric cpVD, pfVD, cpRNFL, mGCC and mean sensitivity (MS). Results Mean cpVD and pfVD in the intact hemiretinae of OAG eyes (59.0% and 51.1%) were higher than the affected hemiretinae (54.7% and 48.3%; p<0.001) but lower than healthy eyes (62.4% and 53.8%; p<0.001). Similar results were noted with cpRNFL and mGCC thickness measurements (p<0.05 for both). The strongest associations between MS in the affected hemifields were found for cpVD (r = 0.707), followed by pfVD (r = 0.615), cpRNFL (r = 0.496) and mGCC (r = 0.482) in the corresponding hemiretinae (p<0.001 for all). Moreover the correlations in the intact hemifields between MS with cpVD and pfVD were found to be higher (r = 0.450 and 0.403) than the correlations between MS and cpRNFL and mGCC thickness measurements (r = 0.340 and 0.290; all p-values <0.05 for all). Conclusions Reduced peripapillary and macular vessel density was detectable in the perimetrically intact hemiretinae of glaucoma eyes with a single-hemifield defect. Moreover vessel density attenuation in both affected and intact hemiretinae was associated with the extent of VF damage in the corresponding hemifields. OCT-A potentially shows promise for identifying glaucomatous damage before focal VF defects are detectable. PMID:28196732

Ezetimibe in Combination With Statins Ameliorates Endothelial Dysfunction in Coronary Arteries After Stenting: The CuVIC Trial (Effect of Cholesterol Absorption Inhibitor Usage on Target Vessel Dysfunction After Coronary Stenting), a Multicenter Randomized Controlled Trial.

PubMed

Takase, Susumu; Matoba, Tetsuya; Nakashiro, Soichi; Mukai, Yasushi; Inoue, Shujiro; Oi, Keiji; Higo, Taiki; Katsuki, Shunsuke; Takemoto, Masao; Suematsu, Nobuhiro; Eshima, Kenichi; Miyata, Kenji; Yamamoto, Mitsutaka; Usui, Makoto; Sadamatsu, Kenji; Satoh, Shinji; Kadokami, Toshiaki; Hironaga, Kiyoshi; Ichi, Ikuyo; Todaka, Koji; Kishimoto, Junji; Egashira, Kensuke; Sunagawa, Kenji

2017-02-01

We sought to investigate whether treatment with ezetimibe in combination with statins improves coronary endothelial function in target vessels in coronary artery disease patients after coronary stenting. We conducted a multicenter, prospective, randomized, open-label, blinded-end point trial among 11 cardiovascular treatment centers. From 2011 to 2013, 260 coronary artery disease patients who underwent coronary stenting were randomly allocated to 2 arms (statin monotherapy, S versus ezetimibe [10 mg/d]+statin combinational therapy, E+S). We defined target vessel dysfunction as the primary composite outcome, which comprised target vessel failure during treatment and at the 6- to 8-month follow-up coronary angiography and coronary endothelial dysfunction determined via intracoronary acetylcholine testing performed in cases without target vessel failure at the follow-up coronary angiography. Coadministration of ezetimibe with statins further lowered low-density lipoprotein cholesterol levels (83±23 mg/dL in S versus 67±23 mg/dL in E+S; P<0.0001), with significant decreases in oxidized low-density lipoprotein and oxysterol levels. Among patients without target vessel failure, 46 out of 89 patients (52%) in the S arm and 34 out of 96 patients (35%) in the E+S arm were found to have coronary endothelial dysfunction (P=0.0256), and the incidence of target vessel dysfunction at follow-up was significantly decreased in the E+S arm (69/112 (62%) in S versus 47/109 (43%) in E+S; P=0.0059). A post hoc analysis of post-treatment low-density lipoprotein cholesterol-matched subgroups revealed that the incidence of both target vessel dysfunction and coronary endothelial dysfunction significantly decreased in the E+S arm, with significant reductions in oxysterol levels. The CuVIC trial (Effect of Cholesterol Absorption Inhibitor Usage on Target Vessel Dysfunction after Coronary Stenting) has shown that ezetimibe with statins, compared with statin monotherapy, improves functional prognoses, ameliorating endothelial dysfunction in stented coronary arteries, and was associated with larger decreases in oxysterol levels. © 2016 American Heart Association, Inc.

Persistence of an intact endometrial matrix and vessels structure in women exposed to VA-2914, a selective progesterone receptor modulator.

PubMed

Ravet, S; Munaut, C; Blacher, S; Brichant, G; Labied, S; Beliard, A; Chabbert-Buffet, N; Bouchard, P; Foidart, J-M; Pintiaux, A

2008-11-01

VA-2914 is a selective progesterone receptor modulator with potential contraceptive activity that induces amenorrhea, whereas progestins cause endometrial spotting and bleeding. This abnormal bleeding due to progestins is a consequence of focal stromal proteolysis by an increase in naked vessel size and density. Our objective was to quantify the effects of VA-2914 on endometrial vascularization, fibrillar matrix, and vascular endothelial growth factor (VEGF)-A expression in endometrial biopsies from 41 women before and after 12 wk daily treatment with a placebo, or 2.5, 5, or 10 mg VA-2914. Collagen fibrillar network was stained by silver impregnation. Vessel area, density, and structure were quantified with a computer-assisted image analysis system after double immunostaining using an anti-von Willebrand factor (endothelial cells) and an anti-alpha smooth muscle actin (vascular smooth muscle cells) marker antibody. VEGF-A mRNAs were quantified by RT-PCR and localized by immunohistochemistry. The endometrial vessels, collagen network, and mRNA levels of VEGF-A were identical during the luteal phase at baseline and in VA-2914 treated women. VEGF-A distribution was unchanged. VA-2914 does not alter the endometrial matrix and cells, and does not modify the endometrial vessel morphology as compared with baseline biopsies.

Intercalibration of research survey vessels on Lake Erie

USGS Publications Warehouse

Tyson, J.T.; Johnson, T.B.; Knight, C.T.; Bur, M.T.

2006-01-01

Fish abundance indices obtained from annual research trawl surveys are an integral part of fisheries stock assessment and management in the Great Lakes. It is difficult, however, to administer trawl surveys using a single vessel-gear combination owing to the large size of these systems, the jurisdictional boundaries that bisect the Great Lakes, and changes in vessels as a result of fleet replacement. When trawl surveys are administered by multiple vessel-gear combinations, systematic error may be introduced in combining catch-per-unit-effort (CPUE) data across vessels. This bias is associated with relative differences in catchability among vessel-gear combinations. In Lake Erie, five different research vessels conduct seasonal trawl surveys in the western half of the lake. To eliminate this systematic bias, the Lake Erie agencies conducted a side-by-side trawling experiment in 2003 to develop correction factors for CPUE data associated with different vessel-gear combinations. Correcting for systematic bias in CPUE data should lead to more accurate and comparable estimates of species density and biomass. We estimated correction factors for the 10 most commonly collected species age-groups for each vessel during the experiment. Most of the correction factors (70%) ranged from 0.5 to 2.0, indicating that the systematic bias associated with different vessel-gear combinations was not large. Differences in CPUE were most evident for vessels using different sampling gears, although significant differences also existed for vessels using the same gears. These results suggest that standardizing gear is important for multiple-vessel surveys, but there will still be significant differences in catchability stemming from the vessel effects and agencies must correct for this. With standardized estimates of CPUE, the Lake Erie agencies will have the ability to directly compare and combine time series for species abundance. ?? Copyright by the American Fisheries Society 2006.

FVID: Fishing Vessel Type Identification Based on VMS Trajectories

NASA Astrophysics Data System (ADS)

Huang, Haiguang; Hong, Feng; Liu, Jing; Liu, Chao; Feng, Yuan; Guo, Zhongwen

2018-05-01

Vessel Monitoring System (VMS) provides a new opportunity for quantified fishing research. Many approaches have been proposed to recognize fishing activities with VMS trajectories based on the types of fishing vessels. However, one research problem is still calling for solutions, how to identify the fishing vessel type based on only VMS trajectories. This problem is important because it requires the fishing vessel type as a preliminary to recognize fishing activities from VMS trajectories. This paper proposes fishing vessel type identification scheme (FVID) based only on VMS trajectories. FVID exploits feature engineering and machine learning schemes of XGBoost as its two key blocks and classifies fishing vessels into nine types. The dataset contains all the fishing vessel trajectories in the East China Sea in March 2017, including 10031 pre-registered fishing vessels and 1350 unregistered vessels of unknown types. In order to verify type identification accuracy, we first conduct a 4-fold cross-validation on the trajectories of registered fishing vessels. The classification accuracy is 95.42%. We then apply FVID to the unregistered fishing vessels to identify their types. After classifying the unregistered fishing vessel types, their fishing activities are further recognized based upon their types. At last, we calculate and compare the fishing density distribution in the East China Sea before and after applying the unregistered fishing vessels, confirming the importance of type identification of unregistered fishing vessels.

Foam vessel for cryogenic fluid storage

DOEpatents

Spear, Jonathan D [San Francisco, CA

2011-07-05

Cryogenic storage and separator vessels made of polyolefin foams are disclosed, as are methods of storing and separating cryogenic fluids and fluid mixtures using these vessels. In one embodiment, the polyolefin foams may be cross-linked, closed-cell polyethylene foams with a density of from about 2 pounds per cubic foot to a density of about 4 pounds per cubic foot.

VESGEN Software for Mapping and Quantification of Vascular Regulators

NASA Technical Reports Server (NTRS)

Parsons-Wingerter, Patricia A.; Vickerman, Mary B.; Keith, Patricia A.

2012-01-01

VESsel GENeration (VESGEN) Analysis is an automated software that maps and quantifies effects of vascular regulators on vascular morphology by analyzing important vessel parameters. Quantification parameters include vessel diameter, length, branch points, density, and fractal dimension. For vascular trees, measurements are reported as dependent functions of vessel branching generation. VESGEN maps and quantifies vascular morphological events according to fractal-based vascular branching generation. It also relies on careful imaging of branching and networked vascular form. It was developed as a plug-in for ImageJ (National Institutes of Health, USA). VESGEN uses image-processing concepts of 8-neighbor pixel connectivity, skeleton, and distance map to analyze 2D, black-and-white (binary) images of vascular trees, networks, and tree-network composites. VESGEN maps typically 5 to 12 (or more) generations of vascular branching, starting from a single parent vessel. These generations are tracked and measured for critical vascular parameters that include vessel diameter, length, density and number, and tortuosity per branching generation. The effects of vascular therapeutics and regulators on vascular morphology and branching tested in human clinical or laboratory animal experimental studies are quantified by comparing vascular parameters with control groups. VESGEN provides a user interface to both guide and allow control over the users vascular analysis process. An option is provided to select a morphological tissue type of vascular trees, network or tree-network composites, which determines the general collections of algorithms, intermediate images, and output images and measurements that will be produced.

Radiographic evaluation of vessel count and density with quantitative magnetic resonance imaging during external breast expansion in Asian women: A prospective clinical trial.

PubMed

Myung, Yujin; Kwon, Heeyeon; Pak, Changsik; Lee, Hobin; Jeong, Jae Hoon; Heo, Chan Yeong

2016-12-01

Breast augmentation with fat transfer does not bear the risks associated with silicone implantation. The method can potentially be especially useful in Asian women, who often reject augmentation mammoplasty with implants. This prospective clinical trial evaluated the effects of external breast expansion on breast density and vessel count using magnetic resonance imaging. Thirty-four enrolled patients were instructed to apply one of two devices, the conventional BRAVA device (used in the AESTES trial) or a novel external expansion device (EVERA) designed for Asian women, continuously for 8 h per day for 12 weeks. For external expansion, the pressure was set to 25 mmHg. Follow-up examinations were performed for 4 weeks after completion of the expansion. The ratio between the fibroglandular and adipose tissues of the breast was measured using T1-weighted MRI, and the number of vessels in the breast tissue was determined before and after the treatment by contrast MRI. Additionally, the volume of the breast was measured by laser scanning before, during, and after the device application. The obtained measurements were compared within and between the groups at different time points. Six patients dropped out, while 28 completed the trial without major side effects or adverse events. External expansion significantly increased breast vessel count in both the EVERA and AESTES groups (p = 0.019, p = 0.022). However, it did not significantly change breast density in either group (p = 0.186, p = 0.638). No significant intergroup differences were noted in vessel count (p = 0.874) or density (p = 0.482). Breast volume increases after 12 weeks of application were statistically significant in both groups, with mean changes of 81 ± 22 cc (AESTES) and 98 ± 30 cc (EVERA) (p < 0.001 in both cases). External expansion resulted in a marked increase in breast vessel count but did not affect breast density. The observed increase in breast volume can be considered substantial for Asian women. Level II, therapeutic study. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

An imaging-based computational model for simulating angiogenesis and tumour oxygenation dynamics

NASA Astrophysics Data System (ADS)

Adhikarla, Vikram; Jeraj, Robert

2016-05-01

Tumour growth, angiogenesis and oxygenation vary substantially among tumours and significantly impact their treatment outcome. Imaging provides a unique means of investigating these tumour-specific characteristics. Here we propose a computational model to simulate tumour-specific oxygenation changes based on the molecular imaging data. Tumour oxygenation in the model is reflected by the perfused vessel density. Tumour growth depends on its doubling time (T d) and the imaged proliferation. Perfused vessel density recruitment rate depends on the perfused vessel density around the tumour (sMVDtissue) and the maximum VEGF concentration for complete vessel dysfunctionality (VEGFmax). The model parameters were benchmarked to reproduce the dynamics of tumour oxygenation over its entire lifecycle, which is the most challenging test. Tumour oxygenation dynamics were quantified using the peak pO2 (pO2peak) and the time to peak pO2 (t peak). Sensitivity of tumour oxygenation to model parameters was assessed by changing each parameter by 20%. t peak was found to be more sensitive to tumour cell line related doubling time (~30%) as compared to tissue vasculature density (~10%). On the other hand, pO2peak was found to be similarly influenced by the above tumour- and vasculature-associated parameters (~30-40%). Interestingly, both pO2peak and t peak were only marginally affected by VEGFmax (~5%). The development of a poorly oxygenated (hypoxic) core with tumour growth increased VEGF accumulation, thus disrupting the vessel perfusion as well as further increasing hypoxia with time. The model with its benchmarked parameters, is applied to hypoxia imaging data obtained using a [64Cu]Cu-ATSM PET scan of a mouse tumour and the temporal development of the vasculature and hypoxia maps are shown. The work underscores the importance of using tumour-specific input for analysing tumour evolution. An extended model incorporating therapeutic effects can serve as a powerful tool for analysing tumour response to anti-angiogenic therapies.

Influence of long-term head-down body position on innervation density in extremity blood vessels

NASA Technical Reports Server (NTRS)

Lorant, M.; Raffai, G.; Nadasy, G.; Feher, E.; Monos, E.

2001-01-01

The aim of the present study was to quantitate and compare the density of nerve terminals (NTD), as well as of their synaptic vesicle population (SyVD) in saphenous and brachial vein and artery, obtained from rats maintained in the horizontal or head-down tilted (HDT) position for two weeks. The same technique was applied as that for the head-up tilt study.

Multiple laser pulses in conjunction with an optical clearing agent to improve the curative effect of cutaneous vascular lesions.

PubMed

Ma, Jun; Chen, Bin; Li, Dong; Zhang, Yue; Ying, Zhaoxia

2018-03-14

Port-wine stain (PWS) birthmark is a congenital microvascular malformation of the skin. A 1064-nm Nd:YAG laser can achieve a deeper treatment, but the weak absorption by blood limits its clinical application. Multiple laser pulses (MLPs) are a potential solution to enhance the curative effect of a Nd:YAG laser. To reduce the pulse number (p n ) required for the thermal destruction of the blood vessel, the effect of glucose in conjunction with MLP was investigated. In vivo experiments were performed on a dorsal skin chamber model. Different concentrations (20, 25, 30, and 40%) of glucose were applied to the sub-dermal side of the hamster skin before laser irradiation. Identical vessels with diameters of 200 ± 30 and 110 ± 20 μm were chosen as representatives of typical PWS vessels. Instant thermal responses of the blood vessel were recorded by a high-speed camera. The required p n for blood vessel damage was compared with that without glucose pretreatment. Results showed that the use of glucose with a concentration of 20% combined with MLP Nd:YAG laser to damage blood vessels is more appropriate because severe hemorrhage or carbonization easily appeared in blood vessels at higher glucose concentration of 25, 30, and 40%. When 20% glycerol is pretreated on the sub-dermal hamster skin, the required p n for blood vessel damage can be significantly decreased for different power densities. For example, p n can be reduced by 40% when the power density is 57 J/cm 2 . In addition, generation of cavitation and bubbles in blood vessels is difficult upon pretreatment with glucose. The combination of glucose with MLP Nd:YAG laser could be an effective protocol for reducing the p n required for blood vessel damage. Randomized controlled trial (RCT) and human trials will be conducted in the future.

Human islet viability and function is maintained during high density shipment in silicone rubber membrane vessels

PubMed Central

Kitzmann, Jennifer P; Pepper, Andrew R; Lopez, Boris G; Pawlick, Rena; Kin, Tatsuya; O’Gorman, Doug; Mueller, Kathryn R; Gruessner, Angelika C; Avgoustiniatos, Efstathios S; Karatzas, Theodore; Szot, Greg L; Posselt, Andrew M; Stock, Peter G; Wilson, John R; Shapiro, AM; Papas, Klearchos K

2014-01-01

The shipment of human islets from processing centers to distant laboratories is beneficial for both research and clinical applications. The maintenance of islet viability and function in transit is critically important. Gas-permeable silicone rubber membrane (SRM) vessels reduce the risk of hypoxia-induced death or dysfunction during high-density islet culture or shipment. SRM vessels may offer additional advantages: they are cost-effective (fewer flasks, less labor needed), safer (lower contamination risk), and simpler (culture vessel can also be used for shipment). Human islets(IE) were isolated from two manufacturing centers and shipped in 10cm2 surface area SRM vessels in temperature and pressure controlled containers to a distant center following at least two days of culture (n = 6). Three conditions were examined: low density (LD), high density (HD), and a micro centrifuge tube negative control (NC). LD was designed to mimic the standard culture density for human islet preparations (200 IE/cm2), while HD was designed to have a 20-fold higher tissue density, which would enable the culture of an entire human isolation in 1–3 vessels. Upon receipt, islets were assessed for viability, measured by oxygen consumption rate normalized to DNA content (OCR/DNA), and quantity, measured by DNA, and, when possible, potency and function with dynamic glucose-stimulated insulin secretion (GSIS) measurements and transplants in immunodeficient B6 rag mice. Post-shipment OCR/DNA was not reduced in HD versus LD, and was substantially reduced in the NC condition. HD islets exhibited normal function post-shipment. Based on the data we conclude that entire islet isolations (up to 400,000 IE) may be shipped using a single, larger SRM vessel with no negative effect on viability and ex vivo and in vivo function. PMID:25131090

Human islet viability and function is maintained during high-density shipment in silicone rubber membrane vessels.

PubMed

Kitzmann, J P; Pepper, A R; Gala-Lopez, B; Pawlick, R; Kin, T; O'Gorman, D; Mueller, K R; Gruessner, A C; Avgoustiniatos, E S; Karatzas, T; Szot, G L; Posselt, A M; Stock, P G; Wilson, J R; Shapiro, A M; Papas, K K

2014-01-01

The shipment of human islets (IE) from processing centers to distant laboratories is beneficial for both research and clinical applications. The maintenance of islet viability and function in transit is critically important. Gas-permeable silicone rubber membrane (SRM) vessels reduce the risk of hypoxia-induced death or dysfunction during high-density islet culture or shipment. SRM vessels may offer additional advantages: they are cost-effective (fewer flasks, less labor needed), safer (lower contamination risk), and simpler (culture vessel can also be used for shipment). IE were isolated from two manufacturing centers and shipped in 10-cm(2) surface area SRM vessels in temperature- and pressure-controlled containers to a distant center after at least 2 days of culture (n = 6). Three conditions were examined: low density (LD), high density (HD), and a microcentrifuge tube negative control (NC). LD was designed to mimic the standard culture density for IE preparations (200 IE/cm(2)), while HD was designed to have a 20-fold higher tissue density, which would enable the culture of an entire human isolation in 1-3 vessels. Upon receipt, islets were assessed for viability (measured by oxygen consumption rate normalized to DNA content [OCR/DNA)]), quantity (measured by DNA), and, when possible, potency and function (measured by dynamic glucose-stimulated insulin secretion measurements and transplants in immunodeficient B6 Rag(+/-) mice). Postshipment OCR/DNA was not reduced in HD vs LD and was substantially reduced in the NC condition. HD islets exhibited normal function postshipment. Based on the data, we conclude that entire islet isolations (up to 400,000 IE) may be shipped using a single, larger SRM vessel with no negative effect on viability and ex vivo and in vivo function. Copyright © 2014 Elsevier Inc. All rights reserved.

The energy density of laser light differentially modulates the skin morphological reorganization in a murine model of healing by secondary intention

PubMed Central

Novaes, Rômulo D; Gonçalves, Reggiani V; Cupertino, Marli C; Araújo, Bruna M; Rezende, Rafael M; Santos, Eliziária C; Leite, João Paulo V; Matta, Sérgio Luis P

2014-01-01

This study investigates the influence of gallium–arsenide (GaAs) laser photobiostimulation applied with different energy densities on skin wound healing by secondary intention in rats. Three circular wounds, 10 mm in diameter, were made on the dorsolateral region of 21 Wistar rats weighting 282.12 ± 36.08 g. The animals were equally randomized into three groups: Group SAL, saline solution 0.9%; Group L3, laser GaAs 3 J/cm2; Group L30, laser GaAs 30 J/cm2. Analyses of cells, blood vessels, collagen and elastic fibres, glycosaminoglycans and wound contraction were performed on the scar tissue from different wounds every 7 days for 21 days. On day 7, 14 and 21, L3 and L30 showed higher collagen and glycosaminoglycan levels compared to SAL (P < 0.05). At day 21, elastic fibres were predominant in L3 and L30 compared to SAL (P < 0.05). Type-III collagen fibres were predominant at day 7 in both groups. There was gradual reduction in these fibres and accumulation of type-I collagen over time, especially in L3 and L30 compared with SAL. Elevated density of blood vessels was seen in L30 on days 7 and 14 compared to the other groups (P < 0.05). On these same days, there was higher tissue cellularity in L3 compared with SAL (P < 0.05). The progression of wound closure during all time points investigated was higher in the L30 group (P < 0.05). Both energy densities investigated increased the tissue cellularity, vascular density, collagen and elastic fibres, and glycosaminoglycan synthesis, with the greater benefits for wound closure being found at the density of 30 J/cm2. PMID:24354418

Patterns in hydraulic architecture from roots to branches in six tropical tree species from cacao agroforestry and their relation to wood density and stem growth

PubMed Central

Kotowska, Martyna M.; Hertel, Dietrich; Rajab, Yasmin Abou; Barus, Henry; Schuldt, Bernhard

2015-01-01

For decades it has been assumed that the largest vessels are generally found in roots and that vessel size and corresponding sapwood area-specific hydraulic conductivity are acropetally decreasing toward the distal twigs. However, recent studies from the perhumid tropics revealed a hump-shaped vessel size distribution. Worldwide tropical perhumid forests are extensively replaced by agroforestry systems often using introduced species of various biogeographical and climatic origins. Nonetheless, it is unknown so far what kind of hydraulic architectural patterns are developed in those agroforestry tree species and which impact this exerts regarding important tree functional traits, such as stem growth, hydraulic efficiency and wood density (WD). We investigated wood anatomical and hydraulic properties of the root, stem and branch wood in Theobroma cacao and five common shade tree species in agroforestry systems on Sulawesi (Indonesia); three of these were strictly perhumid tree species, and the other three tree species are tolerating seasonal drought. The overall goal of our study was to relate these properties to stem growth and other tree functional traits such as foliar nitrogen content and sapwood to leaf area ratio. Our results confirmed a hump-shaped vessel size distribution in nearly all species. Drought-adapted species showed divergent patterns of hydraulic conductivity, vessel density, and relative vessel lumen area between root, stem and branch wood compared to wet forest species. Confirming findings from natural old-growth forests in the same region, WD showed no relationship to specific conductivity. Overall, aboveground growth performance was better predicted by specific hydraulic conductivity than by foliar traits and WD. Our study results suggest that future research on conceptual trade-offs of tree hydraulic architecture should consider biogeographical patterns underlining the importance of anatomical adaptation mechanisms to environment. PMID:25873922

Continuous representation of tumor microvessel density and detection of angiogenic hotspots in histological whole-slide images.

PubMed

Kather, Jakob Nikolas; Marx, Alexander; Reyes-Aldasoro, Constantino Carlos; Schad, Lothar R; Zöllner, Frank Gerrit; Weis, Cleo-Aron

2015-08-07

Blood vessels in solid tumors are not randomly distributed, but are clustered in angiogenic hotspots. Tumor microvessel density (MVD) within these hotspots correlates with patient survival and is widely used both in diagnostic routine and in clinical trials. Still, these hotspots are usually subjectively defined. There is no unbiased, continuous and explicit representation of tumor vessel distribution in histological whole slide images. This shortcoming distorts angiogenesis measurements and may account for ambiguous results in the literature. In the present study, we describe and evaluate a new method that eliminates this bias and makes angiogenesis quantification more objective and more efficient. Our approach involves automatic slide scanning, automatic image analysis and spatial statistical analysis. By comparing a continuous MVD function of the actual sample to random point patterns, we introduce an objective criterion for hotspot detection: An angiogenic hotspot is defined as a clustering of blood vessels that is very unlikely to occur randomly. We evaluate the proposed method in N=11 images of human colorectal carcinoma samples and compare the results to a blinded human observer. For the first time, we demonstrate the existence of statistically significant hotspots in tumor images and provide a tool to accurately detect these hotspots.

Exercise training improves obesity‐related lymphatic dysfunction

PubMed Central

Hespe, Geoffrey E.; Kataru, Raghu P.; Savetsky, Ira L.; García Nores, Gabriela D.; Torrisi, Jeremy S.; Nitti, Matthew D.; Gardenier, Jason C.; Zhou, Jie; Yu, Jessie Z.; Jones, Lee W.

2016-01-01

Key points Obesity results in perilymphatic inflammation and lymphatic dysfunction.Lymphatic dysfunction in obesity is characterized by decreased lymphatic vessel density, decreased collecting lymphatic vessel pumping frequency, decreased lymphatic trafficking of immune cells, increased lymphatic vessel leakiness and changes in the gene expression patterns of lymphatic endothelial cells.Aerobic exercise, independent of weight loss, decreases perilymphatic inflammatory cell accumulation, improves lymphatic function and reverses pathological changes in gene expression in lymphatic endothelial cells. Abstract Although previous studies have shown that obesity markedly decreases lymphatic function, the cellular mechanisms that regulate this response remain unknown. In addition, it is unclear whether the pathological effects of obesity on the lymphatic system are reversible with behavioural modifications. The purpose of this study, therefore, was to analyse lymphatic vascular changes in obese mice and to determine whether these pathological effects are reversible with aerobic exercise. We randomized obese mice to either aerobic exercise (treadmill running for 30 min per day, 5 days a week, for 6 weeks) or a sedentary group that was not exercised and analysed lymphatic function using a variety of outcomes. We found that sedentary obese mice had markedly decreased collecting lymphatic vessel pumping capacity, decreased lymphatic vessel density, decreased lymphatic migration of immune cells, increased lymphatic vessel leakiness and decreased expression of lymphatic specific markers compared with lean mice (all P < 0.01). Aerobic exercise did not cause weight loss but markedly improved lymphatic function compared with sedentary obese mice. Exercise had a significant anti‐inflammatory effect, resulting in decreased perilymphatic accumulation of inflammatory cells and inducible nitric oxide synthase expression. In addition, exercise normalized isolated lymphatic endothelial cell gene expression of lymphatic specific genes, including VEGFR‐3 and Prox1. Taken together, our findings suggest that obesity impairs lymphatic function via multiple mechanisms and that these pathological changes can be reversed, in part, with aerobic exercise, independent of weight loss. In addition, our study shows that obesity‐induced lymphatic endothelial cell gene expression changes are reversible with behavioural modifications. PMID:26931178

Differences in Pre and Post Vascular Patterning Within Retinas from ISS Crew Members and Head-Down Tilt (HDT) Subjects by VESGEN Analysis

NASA Technical Reports Server (NTRS)

Murray, M. C.; Vizzeri, G.; Taibbi, G.; Mason, S. S.; Young, M.; Zanello, S. B.; Parsons-Wingerter, P.

2018-01-01

Accelerated research by NASA has investigated the significant risks incurred during long-duration missions in microgravity for Space Flight-Associated Neuro-ocular Syndrome (SANS, formerly known as Visual Impairments associated with Increased Intracranial Pressure, VIIP) [1]. For our study, NASA's VESsel GENeration Analysis (VESGEN) was used to investigate the role of retinal blood vessels in the etiology of SANS/VIIP. The response of retinal vessels to microgravity was evaluated in astronaut crew members pre and post flight to the International Space Station (ISS), and compared to the response of retinal vessels in healthy volunteers to 6deg head-down tilt during 70 days of bed rest (HDTBR). For the study, we are testing the hypothesis that long-term cephalad fluid shifts resulting in ocular and visual impairments are necessarily mediated in part by retinal blood vessels, and therefore are accompanied by structural adaptations of the vessels. METHODS: Vascular patterns in the retinas of crew members and HDTBR subjects extracted from 30deg infrared (IR) Heidelberg Spectralis images collected pre/postflight and pre/post HDTBR, respectively, were analyzed by VESGEN (patent pending). VESGEN is a mature, automated software developed as a research discovery tool for progressive vascular diseases in the retina and other tissues. The multi-parametric VESGEN analysis generates maps of branching arterial and venous trees quantified by parameters such as the fractal dimension (Df, a modern measure of vascular space-filling capacity), vessel diameters, and densities of vessel length and number classified into specific branching generations according to vascular physiological branching rules. The retrospective study approved by NASA's Institutional Review Board included the analysis of bilateral retinas in eight ISS crew members monitored by routine occupational surveillance and six HDTBR subjects (NASA FARU Campaign 11, for example). The VESGEN analysis was conducted in a blinded fashion, with IR retinal images masked to the subject's identity, ophthalmic and clinical characteristics, and to the temporal sequence of image collection. To complete our study, VESGEN results will be analyzed statistically and correlated with other ophthalmic and medical findings. RESULTS: Preliminary results for changes in the pre to post status of vascular patterning in the retinas of crew members and HDTBR subjects are interestingly opposite. By Df and other vascular branching measures, the space-filling capacity of arterial and venous trees decreased in the majority of crew members (11/16 retinas). In contrast, vascular densities increased in HDTBR subjects by the same parameters (6/10 retinas). To conclude the study, biostatistics and medical analyses will be conducted to quantify and draw conclusions about how the changes associated with flight compare to those associated with HDTBR. CONCLUSIONS: Vascular densities appeared to decrease in the retinas of ISS crew members and increase in HDTBR subjects. Differences in arterial and venous response to cephalad fluid shifts induced by ISS and HDTBR may have resulted from a long-duration conditioning phenomenon (for example, 6-month ISS missions compared to 70 days HDTBR), or the presence of gravity in HDTBR compared to microgravity on the ISS. In addition, increased and decreased vessel diameters for Crew Members and HDTBR, respectively, are subject to limits of im

Antenatal Vitamin D Preserves Placental Vascular and Fetal Growth in Experimental Chorioamnionitis Due to Intra-amniotic Endotoxin Exposure.

PubMed

Cookson, Michael W; Ryan, Sharon L; Seedorf, Gregory J; Dodson, R Blair; Abman, Steve H; Mandell, Erica W

2018-05-01

 Chorioamnionitis (CA) is associated with a high risk for the development of bronchopulmonary dysplasia (BPD) after preterm birth, but mechanisms that increase susceptibility for BPD and strategies to prevent BPD are uncertain. As a model of CA, antenatal intra-amniotic (IA) endotoxin (ETX) exposure alters placental structure, causes fetal growth restriction, increases perinatal mortality, and causes sustained cardiorespiratory abnormalities throughout infancy. Vitamin D (Vit D) has been shown to have both anti-inflammatory and proangiogenic properties. Antenatal IA treatment with Vit D (1,25-(OH) 2 D 3 ) during IA ETX exposure improves survival and increases vascular and alveolar growth in infant rats. Whether IA ETX causes decreased placental vascular development and if the protective effects of prenatal Vit D treatment are due to direct effects on the fetus or to improved placental vascular development remain unknown.  The objective of this study was to determine if IA ETX impairs placental vascular development and Vit D metabolism, and whether 1,25-(OH) 2 D 3 treatment improves placental vascularity after IA ETX exposure during late gestation in pregnant rats.  Fetal rats were exposed to ETX (10 mg), ETX + 1,25-(OH) 2 D 3 (1 ng/mL), 1,25-(OH) 2 D 3 (1 ng/mL), or saline (control) via IA injection at E20 and delivered 2 days later. To assess placental vascular development, histologic sections from the placenta were stained for CD31 and vessel density per high power field (HPF) was determined and analyzed using Matlab software. To determine the effects of ETX on placental Vit D metabolism, Vit D receptor (VDR) and activity of the Vit D conversion enzyme, CYP27B1, were assayed from placental homogenates. Angiogenic mediators were measured by reverse transcription polymerase chain reaction by RNA extracted from placental tissue.  IA ETX reduced placenta and newborn birth weights by 22 and 20%, respectively, when compared with controls (placental weight: 0.60 vs. 0.47 g; p  < 0.0001; birth weight: 4.68 vs. 5.88 g; p  < 0.0001). IA 1,25-(OH) 2 D 3 treatment increased birth weight by 12% in ETX-exposed pups (5.25 vs. 4.68 g; p  < 0.001). IA ETX decreased placental vessel density by 24% in comparison with controls (1,114 vs. 848 vessels per HPF; p  < 0.05). Treatment with IA 1,25-(OH) 2 D 3 increased placenta vessel density twofold after ETX exposure (1,739 vs. 848); p  < 0.0001), and increased vessel density compared with saline controls by 56% (1,739 vs. 1,114; p  < 0.0001). IA ETX decreased both VDR and CYP27B1 expression by 83 and 35%, respectively ( p  < 0.01).  IA ETX decreases placental growth and vessel density and decreases placental VDR and CYP27B1 protein expression, and that antenatal 1,25-(OH) 2 D 3 restores placental weight and vessel density, as well as birth weight. We speculate that 1,25-(OH) 2 D 3 treatment preserves placental function in experimental CA and that these effects may be mediated by increased vascular growth. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Pregnancy at high altitude in the Andes leads to increased total vessel density in healthy newborns

PubMed Central

Gassmann, Norina N.; van Elteren, Hugo A.; Goos, Tom G.; Morales, Claudia R.; Rivera-Ch, Maria; Martin, Daniel S.; Cabala Peralta, Patricia; Passano del Carpio, Agustin; Aranibar Machaca, Saul; Huicho, Luis; Reiss, Irwin K. M.; de Jonge, Rogier C. J.

2016-01-01

The developing human fetus is able to cope with the physiological reduction in oxygen supply occurring in utero. However, it is not known if microvascularization of the fetus is augmented when pregnancy occurs at high altitude. Fifty-three healthy term newborns in Puno, Peru (3,840 m) were compared with sea-level controls. Pre- and postductal arterial oxygen saturation (SpO2) was determined. Cerebral and calf muscle regional tissue oxygenation was measured using near infrared spectroscopy (NIRS). Skin microcirculation was noninvasively measured using incident dark field imaging. Pre- and postductal SpO2 in Peruvian babies was 88.1 and 88.4%, respectively, which was 10.4 and 9.7% lower than in newborns at sea level (P < 0.001). Cerebral and regional oxygen saturation was significantly lower in the Peruvian newborns (cerebral: 71.0 vs. 74.9%; regional: 68.5 vs. 76.0%, P < 0.001). Transcutaneously measured total vessel density in the Peruvian newborns was 14% higher than that in the newborns born at sea level (29.7 vs. 26.0 mm/mm2; P ≤ 0.001). This study demonstrates that microvascular vessel density in neonates born to mothers living at high altitude is higher than that in neonates born at sea level. PMID:27445300

Deficiency of bone marrow beta3-integrin enhances non-functional neovascularization.

PubMed

Watson, Alan R; Pitchford, Simon C; Reynolds, Louise E; Direkze, Natalie; Brittan, Mairi; Alison, Malcolm R; Rankin, Sara; Wright, Nicholas A; Hodivala-Dilke, Kairbaan M

2010-03-01

beta3-Integrin is a cell surface adhesion and signalling molecule important in the regulation of tumour angiogenesis. Mice with a global deficiency in beta3-integrin show increased pathological angiogenesis, most likely due to increased vascular endothelial growth factor receptor 2 expression on beta3-null endothelial cells. Here we transplanted beta3-null bone marrow (BM) into wild-type (WT) mice to dissect the role of BM beta3-integrin deficiency in pathological angiogenesis. Mice transplanted with beta3-null bone marrow show significantly enhanced angiogenesis in subcutaneous B16F0 melanoma and Lewis lung carcinoma (LLC) cell models and in B16F0 melanoma lung metastasis when compared with tumours grown in mice transplanted with WT bone marrow. The effect of bone marrow beta3-integrin deficiency was also assessed in the RIPTAg mouse model of pancreatic tumour growth. Again, angiogenesis in mice lacking BM beta3-integrin was enhanced. However, tumour weight between the groups was not significantly altered, suggesting that the enhanced blood vessel density in the mice transplanted with beta3-null bone marrow was not functional. Indeed, we demonstrate that in mice transplanted with beta3-null bone marrow a significant proportion of tumour blood vessels are non-functional when compared with tumour blood vessels in WT-transplanted controls. Furthermore, beta3-null-transplanted mice showed an increased angiogenic response to VEGF in vivo when compared with WT-transplanted animals. BM beta3-integrin deficiency affects the mobilization of progenitor cells to the peripheral circulation. We show that VEGF-induced mobilization of endothelial progenitor cells is enhanced in mice transplanted with beta3-null bone marrow when compared with WT-transplanted controls, suggesting a possible mechanism underlying the increased blood vessel density seen in beta3-null-transplanted mice. In conclusion, although BM beta3-integrin is not required for pathological angiogenesis, our studies demonstrate a role for BM beta3-integrin in VEGF-induced mobilization of bone marrow-derived cells to the peripheral circulation and for the functionality of those vessels in which BM-derived cells become incorporated.

46 CFR 78.17-20 - Drafts and load line markings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... surface of the water in which the vessel is floating. (2) When an allowance for draft is made for density of the water in which the vessel is floating, this density is to be noted in the official logbook. ...

REPRODUCIBILITY OF VESSEL DENSITY MEASUREMENT WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN EYES WITH AND WITHOUT RETINOPATHY.

PubMed

You, Qisheng; Freeman, William R; Weinreb, Robert N; Zangwill, Linda; Manalastas, Patricia I C; Saunders, Luke J; Nudleman, Eric

2017-08-01

To determine the intravisit and intervisit reproducibility of optical coherence tomography angiography measurements of macular vessel density in eyes with and without retinal diseases. Fifteen healthy volunteers and 22 patients with retinal diseases underwent repeated optical coherence tomography angiography (Angiovue Imaging System, Optovue Inc) scans after pupil dilation on 2 separate visit days. For each visit day, the eyes were scanned twice. Vessel density defined as the proportion of vessel area with flowing blood over the total measurement area was calculated using Angiovue software. Intravisit and intervisit reproducibility were summarized as coefficient of variations and intraclass correlation coefficients were calculated from variance component models. The coefficient of variations representing the intravisit reproducibility of the superficial macular vessel density measurements for different quadrants on 3 mm × 3-mm scans varied from 2.1% to 4.9% and 3.4% to 6.8% for healthy and diseased eyes, respectively, and for the intervisit it was 2.9% to 5.1% and 4.0% to 6.8%, respectively. The coefficient of variations were lower in healthy eyes than in diseased eyes, lower for intravisit than for intervisit, lower on 3 mm × 3-mm scans than on 6 mm × 6-mm scans, and lower for paracentral subfields than for central subfield. The evidence presented here demonstrates good reproducibility of optical coherence tomography angiography for measurement of superficial macula vessel density in both healthy eyes and eyes with diabetic retinopathy without diabetic macular edema.

Evaluation of Sidestream Darkfield Microscopy for Real-Time Imaging Acellular Dermal Matrix Revascularization.

PubMed

DeGeorge, Brent R; Olenczak, J Bryce; Cottler, Patrick S; Drake, David B; Lin, Kant Y; Morgan, Raymond F; Campbell, Christopher A

2016-06-01

Acellular dermal matrices (ADMs) serve as a regenerative framework for host cell integration and collagen deposition to augment the soft tissue envelope in ADM-assisted breast reconstruction-a process dependent on vascular ingrowth. To date noninvasive intra-operative imaging techniques have been inadequate to evaluate the revascularization of ADM. We investigated the safety, feasibility, and efficacy of sidestream darkfield (SDF) microscopy to assess the status of ADM microvascular architecture in 8 patients at the time of tissue expander to permanent implant exchange during 2-stage ADM-assisted breast reconstruction. The SDF microscopy is a handheld device, which can be used intraoperatively for the real-time assessment of ADM blood flow, vessel density, vessel size, and branching pattern. The SDF microscopy was used to assess the microvascular architecture in the center and border zone of the ADM and to compare the native, non-ADM-associated capsule in each patient as a within-subject control. No incidences of periprosthetic infection, explantation, or adverse events were reported after SDF image acquisition. Native capsules demonstrate a complex, layered architecture with an average vessel area density of 14.9 mm/mm and total vessel length density of 12.3 mm/mm. In contrast to native periprosthetic capsules, ADM-associated capsules are not uniformly vascularized structures and demonstrate 2 zones of microvascular architecture. The ADM and native capsule border zone demonstrates palisading peripheral vascular arcades with continuous antegrade flow. The central zone of the ADM demonstrates punctate perforating vascular plexi with intermittent, sluggish flow, and intervening 2- to 3-cm watershed zones. Sidestream darkfield microscopy allows for real-time intraoperative assessment of ADM revascularization and serves as a potential methodology to compare revascularization parameters among commercially available ADMs. Thr SDF microscopy demonstrates that the periprosthetic capsule in ADM-assisted implant-based breast reconstruction is not a uniformly vascularized structure.

Optical Coherence Tomography Angiography in Optic Disc Swelling.

PubMed

Fard, Masoud Aghsaei; Jalili, Jalil; Sahraiyan, Alireza; Khojasteh, Hassan; Hejazi, Marjane; Ritch, Robert; Subramanian, Prem S

2018-05-04

To compare optical coherence tomography angiography (OCT-A) of peripapillary total vasculature and capillaries in patients with optic disc swelling. Cross-sectional study. Twenty nine eyes with acute nonarteritic anterior ischemic optic neuropathy (NAION), 44 eyes with papilledema, 8 eyes with acute optic neuritis, and 48 eyes of normal subjects were imaged using OCT-A. Peripapillary total vasculature information was recorded using a commercial vessel density map. Customized image analysis with major vessel removal was also used to measure whole-image capillary density and peripapillary capillary density (PCD). Mixed models showed that the peripapillary total vasculature density values were significantly lower in NAION eyes, followed by papilledema eyes and control eyes, using commercial software (P < .0001 for all comparisons). The customized software also showed significantly lower PCD of NAION eyes compared with papilledema eyes (all P < .001), but did not show significant differences between papilledema and control subjects. Our software showed significantly lower whole image and PCD in eyes with optic neuritis than papilledema. There was no significant difference between NAION and optic neuritis using our software. The area under the receiver operating curves for discriminating NAION from papilledema eyes and optic neuritis from papilledema eyes was highest for whole-image capillary density (0.94 and 0.80, respectively) with our software, followed by peripapillary total vasculature (0.9 and 0.74, respectively ) with commercial software. OCT-A is helpful to distinguish NAION and papillitis from papilledema. Whole-image capillary density had the greatest diagnostic accuracy for differentiating disc swelling. Copyright © 2018 Elsevier Inc. All rights reserved.

Background gas density and beam losses in NIO1 beam source

NASA Astrophysics Data System (ADS)

Sartori, E.; Veltri, P.; Cavenago, M.; Serianni, G.

2016-02-01

NIO1 (Negative Ion Optimization 1) is a versatile ion source designed to study the physics of production and acceleration of H- beams up to 60 keV. In ion sources, the gas is steadily injected in the plasma source to sustain the discharge, while high vacuum is maintained by a dedicated pumping system located in the vessel. In this paper, the three dimensional gas flow in NIO1 is studied in the molecular flow regime by the Avocado code. The analysis of the gas density profile along the accelerator considers the influence of effective gas temperature in the source, of the gas temperature accommodation by collisions at walls, and of the gas particle mass. The calculated source and vessel pressures are compared with experimental measurements in NIO1 during steady gas injection.

CT diagnosis and differentiation of benign and malignant varieties of solitary fibrous tumor of the pleura

PubMed Central

You, Xiaofang; Sun, Xiwen; Yang, Chunyan; Fang, Yong

2017-01-01

Abstract To investigate computed tomography (CT) characteristics of benign and malignant solitary fibrous tumors of the pleura (SFTPs). Preoperative CTs for 60 SFTP cases (49 benign and 11 malignant) with subsequently confirmed diagnoses were retrospectively analyzed. Tumor morphologies included mounded or mushroom umbrella-shape (19 cases, 31.7%), quasi-circular or oval-shape (30 cases, 50%), and growth resembling a casting mould (12 cases, 20%). Maximum tumor diameters were 1.1 to 18.9 cm (average: 6.4 ± 4.8 cm). Fifty-seven cases had clear boundaries, and 3 had partially coarse boundaries. Twenty-seven cases showed homogeneous density; 33, “geographic”-patterned inhomogeneous density; 6, calcifications; 12, intratumor blood vessels; and 3, thick nourishing peritumoral blood vessels. Pleural thickening (regular and irregular) was found adjacent to tumors in 4, compression of adjacent ribs with absorption and cortical sclerosis in 2, and location adjacent to ribs with bony destruction in 1. Four cases had a small amount of lung tissue enfolded along the boundary, 2 had multiple peritumoral pulmonary bullae, and 9 had small ipsilateral pleural effusions. Compared with benign and malignant SFTPs were larger (P < .001), had inhomogeneous density, and were more commonly associated with intratumor blood vessels and pleural effusions (P < .01). CT revealed characteristic patterns in SFTPs, including casting mould-like growth, rich blood supply, and “geographic”-patterned enhancement. In addition, larger tumor size, inhomogeneous intensities, abundant intratumor blood vessels, and pleural effusions were more common with malignancy. Lastly, multislice CT angiography can reveal feeding arteries and help guide surgical management. PMID:29245313

CT diagnosis and differentiation of benign and malignant varieties of solitary fibrous tumor of the pleura.

PubMed

You, Xiaofang; Sun, Xiwen; Yang, Chunyan; Fang, Yong

2017-12-01

To investigate computed tomography (CT) characteristics of benign and malignant solitary fibrous tumors of the pleura (SFTPs).Preoperative CTs for 60 SFTP cases (49 benign and 11 malignant) with subsequently confirmed diagnoses were retrospectively analyzed.Tumor morphologies included mounded or mushroom umbrella-shape (19 cases, 31.7%), quasi-circular or oval-shape (30 cases, 50%), and growth resembling a casting mould (12 cases, 20%). Maximum tumor diameters were 1.1 to 18.9 cm (average: 6.4 ± 4.8 cm). Fifty-seven cases had clear boundaries, and 3 had partially coarse boundaries. Twenty-seven cases showed homogeneous density; 33, "geographic"-patterned inhomogeneous density; 6, calcifications; 12, intratumor blood vessels; and 3, thick nourishing peritumoral blood vessels. Pleural thickening (regular and irregular) was found adjacent to tumors in 4, compression of adjacent ribs with absorption and cortical sclerosis in 2, and location adjacent to ribs with bony destruction in 1. Four cases had a small amount of lung tissue enfolded along the boundary, 2 had multiple peritumoral pulmonary bullae, and 9 had small ipsilateral pleural effusions. Compared with benign and malignant SFTPs were larger (P < .001), had inhomogeneous density, and were more commonly associated with intratumor blood vessels and pleural effusions (P < .01).CT revealed characteristic patterns in SFTPs, including casting mould-like growth, rich blood supply, and "geographic"-patterned enhancement. In addition, larger tumor size, inhomogeneous intensities, abundant intratumor blood vessels, and pleural effusions were more common with malignancy. Lastly, multislice CT angiography can reveal feeding arteries and help guide surgical management.

Influence of the weighing bar position in vessel on measurement of cement’s particle size distribution by using the buoyancy weighing-bar method

NASA Astrophysics Data System (ADS)

Tambun, R.; Sihombing, R. O.; Simanjuntak, A.; Hanum, F.

2018-02-01

The buoyancy weighing-bar method is a new simple and cost-effective method to determine the particle size distribution both settling and floating particle. In this method, the density change in a suspension due to particle migration is measured by weighing buoyancy against a weighing-bar hung in the suspension, and then the particle size distribution is calculated using the length of the bar and the time-course change in the mass of the bar. The apparatus of this method consists of a weighing-bar and an analytical balance with a hook for under-floor weighing. The weighing bar is used to detect the density change in suspension. In this study we investigate the influences of position of weighing bar in vessel on settling particle size distribution measurements of cement by using the buoyancy weighing-bar method. The vessel used in this experiment is graduated cylinder with the diameter of 65 mm and the position of weighing bar is in center and off center of vessel. The diameter of weighing bar in this experiment is 10 mm, and the kerosene is used as a dispersion liquids. The results obtained show that the positions of weighing bar in vessel have no significant effect on determination the cement’s particle size distribution by using buoyancy weighing-bar method, and the results obtained are comparable to those measured by using settling balance method.

Automated classification and quantitative analysis of arterial and venous vessels in fundus images

NASA Astrophysics Data System (ADS)

Alam, Minhaj; Son, Taeyoon; Toslak, Devrim; Lim, Jennifer I.; Yao, Xincheng

2018-02-01

It is known that retinopathies may affect arteries and veins differently. Therefore, reliable differentiation of arteries and veins is essential for computer-aided analysis of fundus images. The purpose of this study is to validate one automated method for robust classification of arteries and veins (A-V) in digital fundus images. We combine optical density ratio (ODR) analysis and blood vessel tracking algorithm to classify arteries and veins. A matched filtering method is used to enhance retinal blood vessels. Bottom hat filtering and global thresholding are used to segment the vessel and skeleton individual blood vessels. The vessel tracking algorithm is used to locate the optic disk and to identify source nodes of blood vessels in optic disk area. Each node can be identified as vein or artery using ODR information. Using the source nodes as starting point, the whole vessel trace is then tracked and classified as vein or artery using vessel curvature and angle information. 50 color fundus images from diabetic retinopathy patients were used to test the algorithm. Sensitivity, specificity, and accuracy metrics were measured to assess the validity of the proposed classification method compared to ground truths created by two independent observers. The algorithm demonstrated 97.52% accuracy in identifying blood vessels as vein or artery. A quantitative analysis upon A-V classification showed that average A-V ratio of width for NPDR subjects with hypertension decreased significantly (43.13%).

A method for age-matched OCT angiography deviation mapping in the assessment of disease- related changes to the radial peripapillary capillaries.

PubMed

Pinhas, Alexander; Linderman, Rachel; Mo, Shelley; Krawitz, Brian D; Geyman, Lawrence S; Carroll, Joseph; Rosen, Richard B; Chui, Toco Y

2018-01-01

To present a method for age-matched deviation mapping in the assessment of disease-related changes to the radial peripapillary capillaries (RPCs). We reviewed 4.5x4.5mm en face peripapillary OCT-A scans of 133 healthy control eyes (133 subjects, mean 41.5 yrs, range 11-82 yrs) and 4 eyes with distinct retinal pathologies, obtained using spectral-domain optical coherence tomography angiography. Statistical analysis was performed to evaluate the impact of age on RPC perfusion densities. RPC density group mean and standard deviation maps were generated for each decade of life. Deviation maps were created for the diseased eyes based on these maps. Large peripapillary vessel (LPV; noncapillary vessel) perfusion density was also studied for impact of age. Average healthy RPC density was 42.5±1.47%. ANOVA and pairwise Tukey-Kramer tests showed that RPC density in the ≥60yr group was significantly lower compared to RPC density in all younger decades of life (p<0.01). Average healthy LPV density was 21.5±3.07%. Linear regression models indicated that LPV density decreased with age, however ANOVA and pairwise Tukey-Kramer tests did not reach statistical significance. Deviation mapping enabled us to quantitatively and visually elucidate the significance of RPC density changes in disease. It is important to consider changes that occur with aging when analyzing RPC and LPV density changes in disease. RPC density, coupled with age-matched deviation mapping techniques, represents a potentially clinically useful method in detecting changes to peripapillary perfusion in disease.

Complexity of tumor vasculature in clear cell renal cell carcinoma.

PubMed

Qian, Chao-Nan; Huang, Dan; Wondergem, Bill; Teh, Bin Tean

2009-05-15

Clear cell renal cell carcinoma (CCRCC) is a highly vascularized cancer resistant to conventional chemotherapy and radiotherapy. Antiangiogenic therapy has achieved some effectiveness against this unique malignancy. The complexity of the tumor vasculature in CCRCC has led to differences in correlating tumor microvessel density with patient prognosis. The authors' recent findings demonstrated that there were at least 2 major categories of tumor vessels in CCRCC-namely, undifferentiated and differentiated-correlating with patient prognosis in contrasting ways, with higher undifferentiated vessel density indicating poorer prognosis, and higher differentiated vessel density correlating with better prognosis. Furthermore, the presence of pericytes supporting the differentiated vessels varied in CCRCC. The distributions of pericyte coverage and differentiated vessels in CCRCC were uneven. The tumor margin had a higher pericyte coverage rate for differentiated vessels than did the inner tumor area. The uneven distributions of pericyte coverage and differentiated vessels in CCRCC prompted the authors to revisit the mechanism of tumor central necrosis, which was also known to be a prognostic indicator for CCRCC. The discrepancy of prognostic correlation between protein and messenger RNA levels of vascular endothelial growth factor in CCRCC was discussed. The complexity of the tumor vasculature in CCRCC also led the authors to begin to re-evaluate the therapeutic effects of antiangiogenic agents for each type of tumor vessel, which will in turn significantly broaden understanding of tumor angiogenesis and improve therapeutic effect. (c) 2009 American Cancer Society.

Changes in wood density, wood anatomy and hydraulic properties of the xylem along the root-to-shoot flow path in tropical rainforest trees.

PubMed

Schuldt, Bernhard; Leuschner, Christoph; Brock, Nicolai; Horna, Viviana

2013-02-01

It is generally assumed that the largest vessels are occurring in the roots and that vessel diameters and the related hydraulic conductance in the xylem are decreasing acropetally from roots to leaves. With this study in five tree species of a perhumid tropical rainforest in Sulawesi (Indonesia), we searched for patterns in hydraulic architecture and axial conductivity along the flow path from small-diameter roots through strong roots and the trunk to distal sun-canopy twigs. Wood density differed by not more than 10% across the different flow path positions in a species, and branch and stem wood density were closely related in three of the five species. Other than wood density, the wood anatomical and xylem hydraulic traits varied in dependence on the position along the flow path, but were unrelated to wood density within a tree. In contrast to reports from conifers and certain dicotyledonous species, we found a hump-shaped variation in vessel diameter and sapwood area--specific conductivity along the flow path in all five species with a maximum in the trunk and strong roots and minima in both small roots and twigs; the vessel size depended on the diameter of the organ. This pattern might be an adaptation to the perhumid climate with a low risk of hydraulic failure. Despite a similar mean vessel diameter in small roots and twigs, the two distal organs, hydraulically weighted mean vessel diameters were on average 30% larger in small roots, resulting in ∼ 85% higher empirical and theoretical specific conductivities. Relative vessel lumen area in percent of sapwood area decreased linearly by 70% from roots to twigs, reflecting the increase in sclerenchymatic tissue and tracheids in acropetal direction in the xylem. Vessel size was more closely related to the organ diameter than to the distance along the root-to-shoot flow path. We conclude that (i) the five co-occurring tree species show convergent patterns in their hydraulic architecture despite different growth strategies, and (ii) the paradigm assuming continuous acropetal vessel tapering and decrease in specific conductance from fine roots towards distal twigs needs reconsideration.

The Comparison of Regional RNFL and Fundus Vasculature by OCTA in Chinese Myopia Population.

PubMed

Li, Yuanjun; Miara, Hamza; Ouyang, Pingbo; Jiang, Bing

2018-01-01

To determine the correlations between peripapillary vessel density, retinal nerve fibre layer (RNFL) thickness, and myopic indices at retina quadrants with optical coherence tomography angiography (OCTA) in Chinese. Fifty-six subjects with a mean spherical equivalent (MSE) of -3.63 ± 0.29 D were included. Peripapillary RNFL thickness and retinal vessel density in four sectors (superior, nasal, inferior, and temporal quadrants) were determined by OCTA, and correlations of the main outcomes were analyzed. Negative correlations were found between the peripapillary RNFL thickness and axial length (AL) at superior ( r = -0.335, P = 0.001) and inferior ( r = -0.551, P < 0.001) quadrants. There was a significant positive correlation with spherical equivalent (SE) at the corresponding quadrants as well as at the nasal quadrant ( r = 0.339, P = 0.001; r = 0.379, P < 0.001; and r = 0.209, P = 0.039, resp.). Peripapillary retinal vessel density was also negatively correlated with AL at the nasal quadrant ( r = -0.392, P < 0.001), and only at the nasal quadrant, there was a positive correlation between the peripapillary vessel density and SE ( r = 0.319, P = 0.001). The degree of myopia and elongation of AL were negatively correlated with peripapillary RNFL thickness at superior and inferior quadrants and with peripapillary retinal vessel density at the nasal quadrant.

The Comparison of Regional RNFL and Fundus Vasculature by OCTA in Chinese Myopia Population

PubMed Central

2018-01-01

Purpose To determine the correlations between peripapillary vessel density, retinal nerve fibre layer (RNFL) thickness, and myopic indices at retina quadrants with optical coherence tomography angiography (OCTA) in Chinese. Methods Fifty-six subjects with a mean spherical equivalent (MSE) of −3.63 ± 0.29 D were included. Peripapillary RNFL thickness and retinal vessel density in four sectors (superior, nasal, inferior, and temporal quadrants) were determined by OCTA, and correlations of the main outcomes were analyzed. Results Negative correlations were found between the peripapillary RNFL thickness and axial length (AL) at superior (r = −0.335, P = 0.001) and inferior (r = −0.551, P < 0.001) quadrants. There was a significant positive correlation with spherical equivalent (SE) at the corresponding quadrants as well as at the nasal quadrant (r = 0.339, P = 0.001; r = 0.379, P < 0.001; and r = 0.209, P = 0.039, resp.). Peripapillary retinal vessel density was also negatively correlated with AL at the nasal quadrant (r = −0.392, P < 0.001), and only at the nasal quadrant, there was a positive correlation between the peripapillary vessel density and SE (r = 0.319, P = 0.001). Conclusions The degree of myopia and elongation of AL were negatively correlated with peripapillary RNFL thickness at superior and inferior quadrants and with peripapillary retinal vessel density at the nasal quadrant. PMID:29651341

Vessel architecture in human knee cartilage in children: an in vivo susceptibility-weighted imaging study at 7 T.

PubMed

Kolb, Alexander; Robinson, Simon; Stelzeneder, David; Schreiner, Markus; Chiari, Catharina; Windhager, Reinhard; Trattnig, Siegfried; Bohndorf, Klaus

2018-02-26

To evaluate the clinical feasibility of ultrahigh field 7-T SWI to visualize vessels and assess their density in the immature epiphyseal cartilage of human knee joints. 7-T SWI of 12 knees (six healthy volunteers, six patients with osteochondral abnormalities; mean age 10.7 years; 3 female, 9 male) were analysed by two readers, classifying intracartilaginous vessel densities (IVD) in three grades (no vessels, low IVD and high IVD) in defined femoral, tibial and patellar zones. Differences between patients and volunteers, IVDs in different anatomic locations, differences between cartilage overlying osteochondral abnormalities and corresponding normal zones, and differences in age groups were analysed. Interrater reliability showed moderate agreement between the two readers (κ = 0.58, p < 0.001). The comparison of IVDs between patients and volunteers revealed no significant difference (p = 0.706). The difference between zones in the cartilage overlying osteochondral abnormalities to corresponding normal zones showed no significant difference (p = 0.564). IVDs were related to anatomic location, with decreased IVDs in loading areas (p = 0.003). IVD was age dependent, with more vessels present in the younger participants (p = 0.001). The use of SWI in conjunction with ultrahigh field MRI makes the in vivo visualization of vessels in the growing cartilage of humans feasible, providing insights into the role of the vessel network in acquired disturbances. • SWI facilitates in vivo visualization of vessels in the growing human cartilage. • Interrater reliability of the intracartilaginous vessel grading was moderate. • Intracartilaginous vessel densities are dependent on anatomical location and age.

Lymphangiogenesis assessed using three methods is related to tumour grade, breast cancer subtype and expression of basal marker.

PubMed

Niemiec, Joanna; Adamczyk, Agnieszka; Ambicka, Aleksandra; Mucha-Małecka, Anna; Wysocki, Wojciech; Mituś, Jerzy; Ryś, Janusz

2012-11-01

Lymphangiogenesis is a potential indicator of cancer patients' survival. However, there is no standardisation of methodologies applied to the assessment of lymphatic vessel density. In 156 invasive ductal breast cancers (T  1/N+/M0), lymphatic and blood vessels were visualised using podoplanin and CD34, respectively. Based on these markers expression, four parameters were assessed: (i) distribution of podoplanin-stained vessels (DPV) - the percentage of fields with at least one lymphatic vessel (a simple method proposed by us), (ii) lymphatic vessel density (LVD), (iii) LVD to microvessel density ratio (LVD/MVD) and (iv) the expression of podoplanin in cancer-associated fibroblasts. Next, we estimated relations between the above-mentioned parameters and: (i) breast cancer subtype, (ii) tumour grade, and (iii) basal markers expression. We found that intensive lymphangiogenesis, assessed using all studied methods, is positively related to high tumour grade, triple negative or HER2 subtype and expression of basal markers. Whereas, the absence of podoplanin expression in fibroblasts of cancer stroma is related to luminal A subtype, low tumour grade or lack of basal markers expression. Distribution of podoplanin-stained vessels, assessed by a simple method proposed by us (indicating the percentage of fields with at least one lymphatic vessel), might be used instead of the "hot-spot" method.

Lymphangiogenesis and angiogenesis in oral cavity and lower lip squamous cell carcinoma.

PubMed

Alaeddini, Mojgan; Etemad-Moghadam, Shahroo

2016-01-01

Tumors of the lip and oral cavity differ in various aspects; therefore a clarification of the distinctions among these sites may help to better understand the biologic behavior of neoplasms occurring in these locations. Considering that angiogenesis and lymphangiogenesis are two major elements that can influence various aspects of tumor biology, we aimed to compare these factors between squamous cell carcinoma of the lower lip and oral cavity. A total of 84 primary squamous cell carcinomas including 45 oral and 39 lower lip tumors were selected and immunohistochemically stained with monoclonal antibody against D2-40 and CD105. Mean microvessel density was assessed in tumoral tissue, while lymphatic vessel density was calculated in both neoplastic tissue and invasion front. Data were statistically analyzed using t-test and p-values of <0.05 were considered significant. We found a mean microvessel density±standard deviation of 31.94±18.9 in oral cavity and 27.54±20.8 in lower lip squamous cell carcinomas, with no significant difference (p=0.32). Mean lymphatic vessel density±standard deviation was 13.05±8.2 and 16.57±10.79 in of oral cavity and lower lip neoplastic tissue, respectively. The corresponding values were 9.94±5.59 and 12.50±7.8 in the invasive front. Significant differences were not observed in either of the lymphatic vessel density variables between the two sites. According to our results, it seems that the search for additional factors other than those related to the vasculature should continue, to help clarify the differences in biologic behavior between lower lip and oral cavity squamous cell carcinomas. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Differences in Pre and Post Vascular Patterning of Retinas from ISS Crew Members and HDT Subjects by VESGEN Analysis

NASA Technical Reports Server (NTRS)

Murray, M. C.; Vizzeri, G.; Taibbi, G.; Mason, S. S.; Young, M. H.; Zanello, S. B.; Parsons-Wingerter, P. A.

2018-01-01

Accelerated research by NASA [1] has investigated the significant risks for visual and ocular impairments Spaceflight Associated Neuro-Ocular Syndrome /Visual Impairment/Intracranial Pressure (SANS/VIIP) incurred by microgravity spaceflight, especially long-duration missions. Our study investigates the role of blood vessels in the incidence and etiology of SANS/VIIP within the retinas of Astronaut crewmembers pre-and post-flight to the International Space Station (ISS) by NASA's VESsel GENeration Analysis (VESGEN). The response of retinal vessels in crewmembers to microgravity was compared to that of retinal vessels to Head-Down Tilt (HDT) in subjects undergoing 70-Day Bed Rest. The study tests the proposed hypothesis that cephalad fluid shifts missions, resulting in ocular and visual impairments, are necessarily mediated in part by retinal blood vessels, and are therefore accompanied by significant remodeling of retinal vasculature.Vascular patterns in the retinas of crew members and HDTBR subjects extracted from 30° infrared (IR) Heidelberg Spectralis® images collected pre/postflight and pre/post HDTBR, respectively, were analyzed by VESGEN (patent pending). a mature, automated software developed as a research discovery tool for progressive vascular diseases in the retina and other tissues [2]. The weighted, multi-parametric VESGEN analysis generates maps of branching arterial and venous trees and quantification by parameters such as the fractal dimension (Df, a modern measure of vascular space-filling capacity), vessel diameters, and densities of vessel length and number classified into specific branching generations by vascular physiological branching rules [2,3]. The retrospective study approved by NASA’s Institutional Review Board included six HDT subjects (NASA Flight Analogs Research Unit [FARU] Campaign 11; for example, [4]) and eight ISS crewmembers monitored by routine occupational surveillance who provided their study consents to NASA’s Lifetime Surveillance of Astronaut Health (LSAH). For the initial blinded VESGEN phase, ophthalmic retinal images were masked as to subject identity and pre- and post-status. In the second unblinded phase, VESGEN results were analyzed according to the pre- and post-status of left and right retinas matched to each subject. To complete our study, vascular results will be subjected to NASA biostatistical analysis and correlated with other ophthalmic and medical findings. Preliminary results for changes in the pre- to post-status of vascular patterning in the retinas of crewmembers and HDT subjects are strikingly opposite. By Df and other vascular branching measures, the space-filling capacity of arterial and venous trees decreased in a substantial subset of crewmembers (11/16 retinas). In contrast, vascular densities increased in a substantial subset of HDT subjects by the same parameters (6/10 retinas, currently excluding one anomalous subject). To conclude the study, biostatistical and medical analyses will be of critical importance for investigating the validity of these vascular findings. Vascular densities appeared to decrease in the retinas of crewmembers following ISS Missions, and increase in subjects after HDT. The vascular increases and decreases most likely derive primarily from limits of resolution to the ophthalmic imaging that does not capture the smallest vessels, rather than from vessel growth or atrophy. Differences in arterial and venous response to cephalad fluid shifts induced by ISS and HDT may have resulted from a long-duration conditioning phenomenon (for example, 6-month ISS missions compared to 70-day HDT), or the presence of gravity in HDT compared to microgravity onboard the ISS. To conclude our study, the biostatistical and medical analyses will be of critical importance for investigating the validity and significance of the VESGEN findings.

Role of lymphatic vessel density in colorectal cancer: prognostic significance and clinicopathologic correlations.

PubMed

Pappas, A; Lagoudianakis, E; Seretis, C; Koronakis, N; Keramidaris, D; Grapatsas, K; Filis, K; Manouras, A; Salemis, N

2015-06-01

Over the past decades the identification of several molecules that are expressed specifically in the lymphatic endothelial cells has resulted in marked advances in the field of lymphangiogenesis. We aimed to measure LVD in colorectal cancer patients and to compare it with microvascular density (MVD) - a marker of angiogenesis - and patients' clinicopathological parameters and survival, as the measurement of lymphatic vessel density (LVD) has been documented in various tumor types, including colorectal cancer. Fifty one patients who had undergone surgical resection for stage I-III colorectal cancer entered this study. LVD and MVD were determined immunohistochemically with the use of D2-40 and CD34 antibody respectively. The evaluation of LVD was performed by both visual and computer-aided image analysis. The majority of lymphatic vessels were located in the peritumoral areas rather than within the tumor. The results obtained from the image analyzer correlated significantly with the data obtained using visual counting with light microscopy. Both visual and image analysis LVD failed to correlate with patients' age and gender and tumor location, stage, grade, MVD count and survival. The biologic role of the lymphatic vasculature in tumor progression remains controversial. The present study failed to associate LVD with outcome markers and prognosis and further studies would be required to verify our results. © Acta Gastro-Enterologica Belgica.

Grading vascularity from histopathological images based on traveling salesman distance and vessel size

NASA Astrophysics Data System (ADS)

Niazi, M. Khalid Khan; Hemminger, Jessica; Kurt, Habibe; Lozanski, Gerard; Gurcan, Metin

2014-03-01

Vascularity represents an important element of tissue/tumor microenvironment and is implicated in tumor growth, metastatic potential and resistence to therapy. Small blood vessels can be visualized using immunohistochemical stains specific to vascular cells. However, currently used manual methods to assess vascular density are poorly reproducible and are at best semi quantitative. Computer based quantitative and objective methods to measure microvessel density are urgently needed to better understand and clinically utilize microvascular density information. We propose a new method to quantify vascularity from images of bone marrow biopsies stained for CD34 vascular lining cells protein as a model. The method starts by automatically segmenting the blood vessels by methods of maxlink thresholding and minimum graph cuts. The segmentation is followed by morphological post-processing to reduce blast and small spurious objects from the bone marrow images. To classify the images into one of the four grades, we extracted 20 features from the segmented blood vessel images. These features include first four moments of the distribution of the area of blood vessels, first four moments of the distribution of 1) the edge weights in the minimum spanning tree of the blood vessels, 2) the shortest distance between blood vessels, 3) the homogeneity of the shortest distance (absolute difference in distance between consecutive blood vessels along the shortest path) between blood vessels and 5) blood vessel orientation. The method was tested on 26 bone marrow biopsy images stained with CD34 IHC stain, which were evaluated by three pathologists. The pathologists took part in this study by quantifying blood vessel density using gestalt assessment in hematopoietic bone marrow portions of bone marrow core biopsies images. To determine the intra-reader variability, each image was graded twice by each pathologist with two-week interval in between their readings. For each image, the ground truth (grade) was acquired through consensus among the three pathologists at the end of the study. A ranking of the features reveals that the fourth moment of the distribution of the area of blood vessels along with the first moment of the distribution of the shortest distance between blood vessels can correctly grade 68.2% of the bone marrow biopsies, while the intra- and inter-reader variability among the pathologists are 66.9% and 40.0%, respectively.

Contributions of Cu-rich clusters, dislocation loops and nanovoids to the irradiation-induced hardening of Cu-bearing low-Ni reactor pressure vessel steels

NASA Astrophysics Data System (ADS)

Bergner, F.; Gillemot, F.; Hernández-Mayoral, M.; Serrano, M.; Török, G.; Ulbricht, A.; Altstadt, E.

2015-06-01

Dislocation loops, nanovoids and Cu-rich clusters (CRPs) are known to represent obstacles for dislocation glide in neutron-irradiated reactor pressure vessel (RPV) steels, but a consistent experimental determination of the respective obstacle strengths is still missing. A set of Cu-bearing low-Ni RPV steels and model alloys was characterized by means of SANS and TEM in order to specify mean size and number density of loops, nanovoids and CRPs. The obstacle strengths of these families were estimated by solving an over-determined set of linear equations. We have found that nanovoids are stronger than loops and loops are stronger than CRPs. Nevertheless, CRPs contribute most to irradiation hardening because of their high number density. Nanovoids were only observed for neutron fluences beyond typical end-of-life conditions of RPVs. The estimates of the obstacle strength are critically compared with reported literature data.

Rotating Vessels for Growing Protein Crystals

NASA Technical Reports Server (NTRS)

Cottingham, Paul

2005-01-01

Rotating vessels have been proposed as means of growing larger, more nearly uniform protein crystals than would otherwise be possible in the presence of normal Earth gravitation. Heretofore, nonrotating vessels have been used. It is difficult to grow high-quality protein crystals in the terrestrial gravitational field because of convection plumes created by the interaction between gravitation and density gradients in protein-solution depletion layers around growing crystals. The density gradients and the associated convection plumes cause the surfaces of growing crystals to be exposed to nonuniform solution densities, thereby causing the crystals to form in irregular shapes. The microgravitational environment of outer space has been utilized to eliminate gravitation-induced convection, but this approach is generally not favorable because of the high cost and limited availability of space flight. The use of a rotating vessel according to the proposal is intended to ameliorate the effects of gravitation and the resultant convection, relative to the corresponding effects in a non-rotating vessel. The rotation would exert an averaging effect over time, distributing the convective force on the depletion layer. Therefore, the depletion layer would be more nearly uniform and, as a result, the growing crystal would be more nearly perfect. The proposal admits of variations (see figure), including the following: The growing crystal could be rotated about its own central axis or an external axis. The crystal-growth vessel could be of any of various shapes, including cylindrical, hemispherical, conical, and combinations thereof. The crystal-growth vessel could be suspended in a viscous fluid in an outer vessel to isolate the growing crystal from both ambient vibrations and vibrations induced by a mechanism that drives the rotation. The rotation could be coupled to the crystal-growth vessel by viscous or magnetic means. The crystal-growth vessel could be supported within the outer vessel by use of a magnetic field. The crystal-growth vessel and the outer vessel could be configured in a variety of ways to facilitate heat transfer, instrumentation, and rotation.

Flood-Ring Formation and Root Development in Response to Experimental Flooding of Young Quercus robur Trees

PubMed Central

Copini, Paul; den Ouden, Jan; Robert, Elisabeth M. R.; Tardif, Jacques C.; Loesberg, Walter A.; Goudzwaard, Leo; Sass-Klaassen, Ute

2016-01-01

Spring flooding in riparian forests can cause significant reductions in earlywood-vessel size in submerged stem parts of ring-porous tree species, leading to the presence of ‘flood rings’ that can be used as a proxy to reconstruct past flooding events, potentially over millennia. The mechanism of flood-ring formation and the relation with timing and duration of flooding are still to be elucidated. In this study, we experimentally flooded 4-year-old Quercus robur trees at three spring phenophases (late bud dormancy, budswell, and internode expansion) and over different flooding durations (2, 4, and 6 weeks) to a stem height of 50 cm. The effect of flooding on root and vessel development was assessed immediately after the flooding treatment and at the end of the growing season. Ring width and earlywood-vessel size and density were measured at 25- and 75-cm stem height and collapsed vessels were recorded. Stem flooding inhibited earlywood-vessel development in flooded stem parts. In addition, flooding upon budswell and internode expansion led to collapsed earlywood vessels below the water level. At the end of the growing season, mean earlywood-vessel size in the flooded stem parts (upon budswell and internode expansion) was always reduced by approximately 50% compared to non-flooded stem parts and 55% compared to control trees. This reduction was already present 2 weeks after flooding and occurred independent of flooding duration. Stem and root flooding were associated with significant root dieback after 4 and 6 weeks and mean radial growth was always reduced with increasing flooding duration. By comparing stem and root flooding, we conclude that flood rings only occur after stem flooding. As earlywood-vessel development was hampered during flooding, a considerable number of narrow earlywood vessels present later in the season, must have been formed after the actual flooding events. Our study indicates that root dieback, together with strongly reduced hydraulic conductivity due to anomalously narrow earlywood vessels in flooded stem parts, contribute to reduced radial growth after flooding events. Our findings support the value of flood rings to reconstruct spring flooding events that occurred prior to instrumental flood records. PMID:27379108

Influence of myelinated retinal nerve fibers on retinal vessel density measurement with AngioVue OCT angiography.

PubMed

Holló, Gábor

2016-12-01

Myelinated retinal nerve fibers (MRNF) represent an asymptomatic developmental anomaly in which myelin sheaths extend to a group of retinal nerve fibers along their intraocular portion. The additional volume of the myelin sheaths causes displacement of the axons toward the vitreous body. We investigated the effect of localized MRNF on peripapillary vessel density measurement results using optical coherence tomography (OCT) angiography. Peripapillary angioflow density measurements (PAFD, % of the analyzed retinal area) were made with the AngioVue OCT (Optovue Inc., Fremont, USA). In both cases, the predominant position of MRNF was inferonasal to the disk. Vessel density was clearly greater in the area of the MRNF than in the surrounding retina in the optic nerve head (ONH) level, but it was lower than in the surrounding retina in the retinal nerve fiber layer (RNFL) level. In the ONH level, PAFD was higher in the MRNF area than in the spatially corresponding superonasal area (Case 1: 64.6 vs. 57.6 %; Case 2: 65.8 vs. 56.3 %). In contrast, in the RNFL level, PAFD was lower in the MRNF area than in the corresponding superonasal area (Case 1: 60.1 vs. 65.4 %; Case 2: 46.5 vs. 58.5 %). Our cases show that the effect of MRNF on OCT angiography vessel density is different in the different measurement layers. Clinicians may separate decreased vessel density caused by anterior RNFL displacement in MRNF areas from that caused by nerve fiber damage in optic neuropathies by evaluating PAFD in both the ONH and RNFL levels.

Quantitative immunohistochemistry of factor VIII-related antigen in breast carcinoma: a comparison of computer-assisted image analysis with established counting methods.

PubMed

Kohlberger, P D; Obermair, A; Sliutz, G; Heinzl, H; Koelbl, H; Breitenecker, G; Gitsch, G; Kainz, C

1996-06-01

Microvessel density in the area of the most intense neovascularization in invasive breast carcinoma is reported to be an independent prognostic factor. The established method of enumeration of microvessel density is to count the vessels using an ocular raster (counted microvessel density [CMVD]). The vessels were detected by staining endothelial cells using Factor VIII-related antigen. The aim of the study was to compare the CMVD results with the percentage of factor VIII-related antigen-stained area using computer-assisted image analysis. A true color red-green-blue (RGB) image analyzer based on a morphologically reduced instruction set computer processor was used to evaluate the area of stained endothelial cells. Sixty invasive breast carcinomas were included in the analysis. There was no significant correlation between the CMVD and the percentage of factor VIII-related antigen-stained area (Spearman correlation coefficient = 0.24, confidence interval = 0.02-0.46). Although high CMVD was significantly correlated with poorer recurrence free survival (P = .024), percentage of factor VIII-related antigen-stained area showed no prognostic value. Counted microvessel density and percentage of factor VIII-related antigen-stained area showed a highly significant correlation with vessel invasion (P = .0001 and P = .02, respectively). There was no correlation between CMVD and percentage of factor VIII-related antigen-stained area with other prognostic factors. In contrast to the CMVD within malignant tissue, the percentage of factor VIII-related antigen-stained area is not suitable as an indicator of prognosis in breast cancer patients.

Reduction of Peripapillary Vessel Density by Optical Coherence Tomography Angiography from the Acute to the Atrophic Stage in Non-Arteritic Anterior Ischaemic Optic Neuropathy.

PubMed

Rebolleda, Gema; Díez-Álvarez, Laura; García Marín, Yoel; de Juan, Victoria; Muñoz-Negrete, Francisco J

2018-06-26

To analyse superficial peripapillary vascularization in non-arteritic anterior ischaemic optic neuropathy (NAION) at acute and atrophic (3 months) stage. Prospective case-control study including 6 patients with NAION and 10 age-matched healthy controls evaluated with optical coherence tomography angiography (OCT-A; Angioplex-Cirrus) at acute and atrophic stage. Apart from the -commercially provided measurements for vessel density (VD) and perfusion density (PD), a custom image analysis was used to quantify the peripapillary capillary density (PCD). NAION-group demonstrated a significant decrease in the PCD, VD and PD compared with fellow unaffected and control groups at acute and atrophic stage. At 3 months, the average and the temporal sector in PCD correlated with logMAR VA (-0.943, p = 0.005 and -0.829, p = 0.042 for average and temporal sectors respectively) and with MD (0.943, p = 0.005; and 0.899; p = 0.015, respectively). Over 3 months, there was a significant PCD reduction at the temporal sector and at the inner circle in VD and PD, which correlated with ganglion cell-inner plexiform layer (GCIPL) thinning over the 3 months period after the acute NAION (0.749, p = 0.020; 0.885, p = 0.002; 0.767, p = 0.016 respectively). Both strategies demonstrated a significant peripapillary microvascular dropout in NAION, but the customized analysis detected them -earlier. A progressive vessel reduction occurs within the first 3 months, which correlates with GCIPL thinning. © 2018 S. Karger AG, Basel.

Lymphatic and blood vessels in male breast cancer.

PubMed

Niemiec, Joanna; Sas-Korczynska, Beata; Harazin-Lechowska, Agnieszka; Martynow, Dariusz; Adamczyk, Agnieszka

2015-02-01

It is assumed that lymphatic vessels are responsible for breast cancer dissemination. In 32 male breast carcinomas we evaluated the correlation between: (i) lymphatic vessel density (LVD), distribution of podoplanin-immunostained vessels (DPV), blood vessel density (BVD), infiltration of immune cells and (ii) known clinicopathological parameters. Lymphatic and blood vessels were found in 77.8% and 100% of breast carcinomas, respectively. Double-negative estrogen and progesterone receptor tumors (ER-/PR-) presented significantly higher LVD than ER/PR positive cases, while high-grade tumors exhibited significantly higher DPV than low-grade carcinomas. We detected significantly higher frequency of vascular invasion in high-grade and double-negative carcinomas than in low-grade and ER/PR-positive ones, respectively. The relationship between high number of lymphatic vessels and high tumor grade or steroid receptor negativity might confirm the hypothesis regarding the influence of lymphangiogenesis on the formation of a more aggressive phenotype in male breast cancer. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Is the peripapillary retinal perfusion related to myopia in healthy eyes? A prospective comparative study.

PubMed

Wang, Xiaolei; Kong, Xiangmei; Jiang, Chunhui; Li, Mengwei; Yu, Jian; Sun, Xinghuai

2016-03-11

The aim of this study was to evaluate the peripapillary and parafoveal perfusion of young, healthy myopic subjects with spectral domain optical coherence tomography (OCT) angiography. A prospective comparative study was conducted from December 2014 to January 2015. Participants recruited from a population-based study performed by the Eye, Ear, Nose and Throat Hospital of Fudan University in Shanghai. A total of 78 Chinese normal subjects (78 eyes) with different refraction were included. Myopia was divided into 4 groups on the basis of the refractive status: 20 eyes with emmetropia (mean spherical equivalent (MSE) 0.50D to -0.50D), 20 eyes with mild myopia (MSE -0.75D to -2.75D), 20 eyes with moderate myopia (MSE -3.00D to -5.75D), and 18 eyes with high myopia (MSE≤-6.00D). Peripapillary and parafoveal retinal and choroidal perfusion parameters and their relationships with axial length (AL) and retinal nerve fibre layer (RNFL) thickness were analysed. Significant differences were found for the retinal flow index and vessel density in the peripapillary area among the 4 groups, but not in the parafoveal area. The high myopia group had the lowest peripapillary retinal flow index and vessel density. In addition, there was a negative correlation (β=-0.002, p=0.047) between the AL and peripapillary retinal flow index and a positive correlation between RNFL thickness and the peripapillary retinal perfusion parameters (flow index: β=0.001, p=0.006; vessel density: β=0.350, p=0.002) even after adjustment for other variables. Highly myopic eyes have a decreased peripapillary retinal perfusion compared with emmetropic eyes. Such vascular features might increase the susceptibility to vascular-related eye diseases. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Exercise training improves obesity-related lymphatic dysfunction.

PubMed

Hespe, Geoffrey E; Kataru, Raghu P; Savetsky, Ira L; García Nores, Gabriela D; Torrisi, Jeremy S; Nitti, Matthew D; Gardenier, Jason C; Zhou, Jie; Yu, Jessie Z; Jones, Lee W; Mehrara, Babak J

2016-08-01

Obesity results in perilymphatic inflammation and lymphatic dysfunction. Lymphatic dysfunction in obesity is characterized by decreased lymphatic vessel density, decreased collecting lymphatic vessel pumping frequency, decreased lymphatic trafficking of immune cells, increased lymphatic vessel leakiness and changes in the gene expression patterns of lymphatic endothelial cells. Aerobic exercise, independent of weight loss, decreases perilymphatic inflammatory cell accumulation, improves lymphatic function and reverses pathological changes in gene expression in lymphatic endothelial cells. Although previous studies have shown that obesity markedly decreases lymphatic function, the cellular mechanisms that regulate this response remain unknown. In addition, it is unclear whether the pathological effects of obesity on the lymphatic system are reversible with behavioural modifications. The purpose of this study, therefore, was to analyse lymphatic vascular changes in obese mice and to determine whether these pathological effects are reversible with aerobic exercise. We randomized obese mice to either aerobic exercise (treadmill running for 30 min per day, 5 days a week, for 6 weeks) or a sedentary group that was not exercised and analysed lymphatic function using a variety of outcomes. We found that sedentary obese mice had markedly decreased collecting lymphatic vessel pumping capacity, decreased lymphatic vessel density, decreased lymphatic migration of immune cells, increased lymphatic vessel leakiness and decreased expression of lymphatic specific markers compared with lean mice (all P < 0.01). Aerobic exercise did not cause weight loss but markedly improved lymphatic function compared with sedentary obese mice. Exercise had a significant anti-inflammatory effect, resulting in decreased perilymphatic accumulation of inflammatory cells and inducible nitric oxide synthase expression. In addition, exercise normalized isolated lymphatic endothelial cell gene expression of lymphatic specific genes, including VEGFR-3 and Prox1. Taken together, our findings suggest that obesity impairs lymphatic function via multiple mechanisms and that these pathological changes can be reversed, in part, with aerobic exercise, independent of weight loss. In addition, our study shows that obesity-induced lymphatic endothelial cell gene expression changes are reversible with behavioural modifications. © 2016 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Solvent selection in ultrasonic-assisted emulsification microextraction: Comparison between high- and low-density solvents by means of novel type of extraction vessel.

PubMed

Nojavan, Saeed; Gorji, Tayebeh; Davarani, Saied Saeed Hosseiny; Morteza-Najarian, Amin

2014-08-01

There are numerous published reports about dispersive liquid phase microextraction of the wide range of substances, however, till now no broadly accepted systematic and purpose oriented selection of extraction solvent has been proposed. Most works deal with the optimization of available solvents without adequate pre-consideration of properness. In this study, it is tried to compare the performances of low- and high-density solvents at the same conditions by means of novel type of extraction vessel with head and bottom conical shape. Extraction efficiencies of seven basic pharmaceutical compounds using eighteen common organic solvents were studied in this work. It was much easier to work with high-density solvents and they mostly showed better performances. This work shows that although exact predicting the performance of the solvents is multifaceted case but the pre-consideration of initial selection of solvents with attention to the physiochemical properties of the desired analytes is feasible and promising. Finally, the practicality of the method for extraction from urine and plasma samples was investigated. Copyright © 2014 Elsevier B.V. All rights reserved.

Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents1

PubMed Central

Galiè, Mirco; D'Onofrio, Mirko; Montani, Maura; Amici, Augusto; Calderan, Laura; Marzola, Pasquina; Benati, Donatella; Merigo, Flavia; Marchini, Cristina; Sbarbati, Andrea

2005-01-01

Abstract Contrast-enhanced ultrasound (CEUS) is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 µm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes. PMID:15967105

Relationship of mast cell density with lymphangiogenesis and prognostic parameters in breast carcinoma.

PubMed

Keser, Sevinc H; Kandemir, Nilufer O; Ece, Dilek; Gecmen, Gonca G; Gul, Aylin E; Barisik, Nagehan O; Sensu, Sibel; Buyukuysal, Cagatay; Barut, Figen

2017-04-01

In many cancers, mast cell density (MCD) in the tumor microenvironment is associated with tumor progression and, to a greater extent, angiogenesis. Our study was designed to investigate the correlation between MCD, tumor lymphangiogenesis, and several well-established prognostic parameters in breast cancer. One hundred and four cases of invasive breast carcinoma diagnosed in our clinic between 2007 and 2011 were included. Mast cells and lymphatic vessels were stained with toluidine blue and D2-40, respectively, and their densities were calculated in various areas of tumors and lymph nodes. The variables of MCD and lymphatic vessel density (LVD) were compared using prognostic parameters as well as with each other. As tumor size and volume increased, MCD increased comparably in metastatic lymph nodes; intratumoral and peritumoral LVD also increased. Lymphovascular invasion, lymphatic invasion, perineural invasion, and estrogen receptor positivity were positively related to intratumoral MCD. The relationship between peritumoral MCD and nontumoral breast tissue MCD was statistically significant. Stage was correlated with MCD in metastatic lymph nodes. Metastatic lymph node MCD and intratumoral MCD were also significantly related. Stage, lymphatic invasion, perineural invasion, lymphovascular invasion, and metastatic lymph node MCD were all correlated with intratumoral and/or peritumoral LVD. As nuclear grade increased, intratumoral LVD became higher. In breast carcinoma, MCD, depending on its location, was related to several prognostic parameters. Notably, mast cells may have at least some effect on lymphangiogenesis, which appears to be a predictor of tumor progression. Copyright © 2017. Published by Elsevier Taiwan.

Salt management strategy defines the stem and leaf hydraulic characteristics of six mangrove tree species.

PubMed

Jiang, Guo-Feng; Goodale, Uromi Manage; Liu, Yan-Yan; Hao, Guang-You; Cao, Kun-Fang

2017-03-01

Mangroves in hypersaline coastal habitats are under constant high xylem tension and face great risk of hydraulic dysfunction. To investigate the relationships between functional traits and salt management, we measured 20 hydraulic and photosynthetic traits in four salt-adapted (SA) and two non-SA (NSA) mangrove tree species in south China. The SA species included two salt secretors (SSs), Avicennia marina (Forsskål) Vierhapper and Aegiceras corniculatum (L.) Blanco and two salt excluders (SEs), Bruguiera gymnorrhiza (L.) Savigny and Kandelia obovata (L.) Sheue et al. The two NSA species were Hibiscus tiliaceus (L.) and Pongamia pinnata (L.) Merr. Extremely high xylem cavitation resistance, indicated by water potential at 50% loss of xylem conductivity (Ψ50; -7.85 MPa), was found in SEs. Lower cavitation resistance was observed in SSs, and may result from incomplete salt removal that reduces the magnitude of xylem tension required to maintain water uptake from the soil. Surprisingly, the NSA species, P. pinnata, had very low Ψ50 (-5.44 MPa). Compared with NSAs, SAs had lower photosynthesis, vessel density, hydraulic conductivity and vessel diameter, but higher sapwood density. Eight traits were strongly associated with species' salt management strategies, with predawn water potential (ΨPD) and mean vessel diameter accounting for 95% flow (D95) having the most significant association; D95 separated SAs from NSAs and SEs had the lowest ΨPD. There was significant coupling between hydraulic traits and carbon assimilation traits. Instead of hydraulic safety being compromised by xylem efficiency, mangrove species with higher safety had higher efficiency and greater sapwood density (ρSapwood), but there was no relationship between ρSapwood and efficiency. Principal component analysis differentiated the species of the three salt management strategies by loading D, D95 and vessel density on the first axis and loading ΨPD, Ψ50 and water potential at 12% loss of xylem conductivity (Ψ12), ρSapwood and quantum yield on the second axis. Our results provide the first comparative characterization of hydraulic and photosynthetic traits among mangroves with different salt management strategies. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

OCT-based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes.

PubMed

Men, Shaojie; Wong, Jennifer Manyu; Welch, Emily J; Xu, Jingjiang; Song, Shaozhen; Deegan, Anthony J; Ravichander, Aarthi; Casavant, Benjamin; Berthier, Erwin; Wang, Ruikang K

2018-05-25

To measure and compare microvascular responses within the skin of the upper arm to local stimuli, such as heating or rubbing, through the use of optical coherence tomography angiography (OCTA), and to investigate its impact on blood volume collection. With the use of heat packs or rubbing, local stimulation was applied to the skin of either the left or right upper arm. Data from the stimulated sites were obtained using OCTA comparing pre- and post-stimulation microvascular parameters, such as vessel density, mean vessel diameter, and mean avascular pore size. Additionally, blood was collected using a newly designed collection device and volume was recorded to evaluate the effect of the skin stimulation. Nineteen subjects were recruited for local stimulation study (including rubbing and heating) and 21 subjects for blood drawn study. Of these subjects, 14 agreed to participate in both studies. OCTA was successful in monitoring and measuring minute changes in the microvasculature of the stimulated skin. Compared to baseline, significant changes after local heating and rubbing were respectively found in vessel density (16% [P = 0.0004] and 33% [P < 0.0001] increase), mean vessel diameter (14% and 11% increase) and mean avascular pore size (5% [P = 0.0068] and 8% [P = 0.0005] decrease) after stimulations. A gradual recovery was recorded for each parameter, with no difference being measured after 30 minutes. Blood collection volumes significantly increased after stimulations of heating (48% increase; P = 0.049) and rubbing (78% increase; P = 0.048). Significant correlations were found between blood volume and microvascular parameters except mean avascular pore size under the heating condition. OCTA can provide important information regarding microvascular adaptations to local stimuli. With that, both heating and rubbing of the skin have positive effects on blood collection capacity, with rubbing having the most significant effect. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Broad Anatomical Variation within a Narrow Wood Density Range--A Study of Twig Wood across 69 Australian Angiosperms.

PubMed

Ziemińska, Kasia; Westoby, Mark; Wright, Ian J

2015-01-01

Just as people with the same weight can have different body builds, woods with the same wood density can have different anatomies. Here, our aim was to assess the magnitude of anatomical variation within a restricted range of wood density and explore its potential ecological implications. Twig wood of 69 angiosperm tree and shrub species was analyzed. Species were selected so that wood density varied within a relatively narrow range (0.38-0.62 g cm-3). Anatomical traits quantified included wood tissue fractions (fibres, axial parenchyma, ray parenchyma, vessels, and conduits with maximum lumen diameter below 15 μm), vessel properties, and pith area. To search for potential ecological correlates of anatomical variation the species were sampled across rainfall and temperature contrasts, and several other ecologically-relevant traits were measured (plant height, leaf area to sapwood area ratio, and modulus of elasticity). Despite the limited range in wood density, substantial anatomical variation was observed. Total parenchyma fraction varied from 0.12 to 0.66 and fibre fraction from 0.20 to 0.74, and these two traits were strongly inversely correlated (r = -0.86, P < 0.001). Parenchyma was weakly (0.24 ≤|r|≤ 0.35, P < 0.05) or not associated with vessel properties nor with height, leaf area to sapwood area ratio, and modulus of elasticity (0.24 ≤|r|≤ 0.41, P < 0.05). However, vessel traits were fairly well correlated with height and leaf area to sapwood area ratio (0.47 ≤|r|≤ 0.65, all P < 0.001). Modulus of elasticity was mainly driven by fibre wall plus vessel wall fraction rather than by the parenchyma component. Overall, there seem to be at least three axes of variation in xylem, substantially independent of each other: a wood density spectrum, a fibre-parenchyma spectrum, and a vessel area spectrum. The fibre-parenchyma spectrum does not yet have any clear or convincing ecological interpretation.

Vessel density, retinal thickness, and choriocapillaris vascular flow in myopic eyes on OCT angiography.

PubMed

Milani, Paolo; Montesano, Giovanni; Rossetti, Luca; Bergamini, Fulvio; Pece, Alfredo

2018-06-06

To investigate foveal avascular zone area, macular vascular density, choroidal thickness, and outer retina and choriocapillaris flow in myopic eyes by OCT angiography. Automated macular maps and flow calculations were retrospectively evaluated in 42 myopic and in 40 control eyes. Myopic eyes presented lower whole superficial vessel density (46.4 ± 4.9 vs. 51.6 ± 3.6%, P < 0.0001) and higher flow area in the outer retina (1.3 ± 0.2 vs. 1.1 ± 0.3 mm 2 , P = 0.0012). Between the myopic and non-myopic eyes, no significant differences could be detected in the choriocapillaris perfusion area (1.9 ± 0.07 vs. 1.9 ± 0.05 mm 2 , respectively; P = 0.55) and in the foveal avascular zone area (0.23 ± 0.1 vs. 0.26 ± 0.1 mm 2 , respectively; P = 0.12). The spherical correction positively correlated with superficial vessel density and negatively correlated with outer retina perfusion (P ≤ 0.0021). The superficial vessel density and the local retinal thickness positively correlated at all macular locations (P < 0.005), especially in the foveal region (P < 0.0001). Eyes with high myopia present reduced superficial vascular density and increased outer retina flow. Superficial vascular density and retinal thickness appear to be significantly correlated.

Lymphatic vessel density in the neoplastic progression of Barrett's oesophagus to adenocarcinoma

PubMed Central

Brundler, M‐A; Harrison, J A; de Saussure, B; de Perrot, M; Pepper, M S

2006-01-01

Background Oesophageal adenocarcinoma is an aggressive neoplasm with poor prognosis as a result of early lymph node metastasis. Aims To measure lymphatic vessel density (LVD) in the neoplastic progression from Barrett's metaplasia to adenocarcinoma and determine whether LVD can predict the risk of cancer. In addition, to correlate LVD with lymph node metastasis and assess whether LVD could be used as a prognostic indicator for outcome or survival. Methods LVD and microvascular density (MVD) were assessed after immunohistochemical staining of vessels in Barrett's metaplasia, dysplasia, and adenocarcinoma tissues and were correlated with clinicopathological features. Results LVD was significantly reduced in adenocarcinoma, being half that seen in normal stomach/oesophagus or metaplasia/dysplasia. LVD did not correlate with tumour grade, stage, or clinical outcome; however, patients who had either lymph node metastasis or invasion of tumour cells into peritumorous lymphatic vessels had a significantly worse overall survival. MVD was also assessed as a prognostic marker; its increase appeared to be linked more with the development of Barrett's metaplasia than adenocarcinoma. Conclusions The reduction in lymphatic vessel numbers was not useful for determining disease outcome in the patient group studied. It is the entry of tumour cells into pre‐existing peritumorous lymphatic vessels that confers a significantly worse overall survival. PMID:16443737

The potential role of perivascular lymphatic vessels in preservation of kidney allograft function.

PubMed

Tsuchimoto, Akihiro; Nakano, Toshiaki; Hasegawa, Shoko; Masutani, Kosuke; Matsukuma, Yuta; Eriguchi, Masahiro; Nagata, Masaharu; Nishiki, Takehiro; Kitada, Hidehisa; Tanaka, Masao; Kitazono, Takanari; Tsuruya, Kazuhiko

2017-08-01

Lymphangiogenesis occurs in diseased native kidneys and kidney allografts, and correlates with histological injury; however, the clinical significance of lymphatic vessels in kidney allografts is unclear. This study retrospectively reviewed 63 kidney transplant patients who underwent protocol biopsies. Lymphatic vessels were identified by immunohistochemical staining for podoplanin, and were classified according to their location as perivascular or interstitial lymphatic vessels. The associations between perivascular lymphatic density and kidney allograft function and pathological findings were analyzed. There were no significant differences in perivascular lymphatic densities in kidney allograft biopsy specimens obtained at 0 h, 3 months and 12 months. The groups with higher perivascular lymphatic density showed a lower proportion of progression of interstitial fibrosis/tubular atrophy grade from 3 to 12 months (P for trend = 0.039). Perivascular lymphatic density was significantly associated with annual decline of estimated glomerular filtration rate after 12 months (r = -0.31, P = 0.017), even after adjusting for multiple confounders (standardized β = -0.30, P = 0.019). High perivascular lymphatic density is associated with favourable kidney allograft function. The perivascular lymphatic network may be involved in inhibition of allograft fibrosis and stabilization of graft function.

Yip - Development and Application of a High-Speed Three-Dimensional Density Measurement Technique for Aero-Optic Applications

DTIC Science & Technology

2011-03-25

mixing between two streams of different temperature/density. In addition, there are also regions of high density and high pressure in the braid region...acetone seeding in this work was as follows. A small pressure vessel was filled with liquid acetone and pressurized using a nitrogen tank. An EPDM hose ...through the EPDM hose , out of the pressure vessel, and ultimately through a wall fitting. This wall fitting was connected through the wall of the

Age-Related Alterations in the Retinal Microvasculature, Microcirculation, and Microstructure.

PubMed

Wei, Yantao; Jiang, Hong; Shi, Yingying; Qu, Dongyi; Gregori, Giovanni; Zheng, Fang; Rundek, Tatjana; Wang, Jianhua

2017-07-01

To characterize age-related alterations in the retinal microcirculation, microvascular network, and microstructure in healthy subjects. Seventy-four healthy subjects aged from 18 to 82 years were recruited and divided into four age groups (G1 with age <35 years, G2 with age 35 ∼ 49 years, G3 with age 50 ∼ 64 years, and G4 with age ≥65 years). Custom ultra-high resolution optical coherence tomography (UHR-OCT) was used to acquire six intraretinal layers of the macula. OCT angiography (OCTA) was used to image the retinal microvascular network. The retinal blood flow velocity (BFV) was measured using a Retinal Function Imager (RFI). Compared to G1, G2 had significant thinning of the retinal nerve fiber layer (RNFL) (P < 0.05), while G3 had thinning of the RNFL and ganglion cell and inner plexiform layer (GCIPL) (P < 0.05), in addition to thickening of the outer plexiform layer (OPL) and photoreceptor layer (PR) (P < 0.05). G4 had loss in retinal vessel density, thinning in RNFL and GCIPL, and decrease in venular BFV, in addition to thickening of the OPL and PR (P < 0.05). Age was negatively related to retinal vessel densities, the inner retinal layers, and venular BFV (P < 0.05). By contrast, age was positively related to OPL and PR (P < 0.05). During aging, decreases in retinal vessel density, inner retinal layer thickness, and venular BFV were evident and impacted each other as observed by simultaneous changes in multiple retinal components.

High Energy Density Regenerative Fuel Cell Systems for Terrestrial Applications

NASA Technical Reports Server (NTRS)

Burke, Kenneth A.

1999-01-01

Regenerative Fuel Cell System (RFCS) technology for energy storage has been a NASA power system concept for many years. Compared to battery-based energy storage systems, RFCS has received relatively little attention or resources for development because the energy density and electrical efficiency were not sufficiently attractive relative to advanced battery systems. Even today, RFCS remains at a very low technology readiness level (TRL of about 2 indicating feasibility has been demonstrated). Commercial development of the Proton Exchange Membrane (PEM) fuel cells for automobiles and other terrestrial applications and improvements in lightweight pressure vessel design to reduce weight and improve performance make possible a high energy density RFCS energy storage system. The results from this study of a lightweight RFCS energy storage system for a remotely piloted, solar-powered, high altitude aircraft indicate an energy density up to 790 w-h/kg with electrical efficiency of 53.4% is attainable. Such an energy storage system would allow a solar-powered aircraft to carry hundreds of kilograms of payload and remain in flight indefinitely for use in atmospheric research, earth observation, resource mapping. and telecommunications. Future developments in the areas of hydrogen and oxygen storage, pressure vessel design, higher temperature and higher- pressure fuel cell operation, unitized regenerative fuel cells, and commercial development of fuel cell technology will improve both the energy density and electrical efficiency of the RFCS.

Analysis and Design of Cryogenic Pressure Vessels for Automotive Hydrogen Storage

NASA Astrophysics Data System (ADS)

Espinosa-Loza, Francisco Javier

Cryogenic pressure vessels maximize hydrogen storage density by combining the high pressure (350-700 bar) typical of today's composite pressure vessels with the cryogenic temperature (as low as 25 K) typical of low pressure liquid hydrogen vessels. Cryogenic pressure vessels comprise a high-pressure inner vessel made of carbon fiber-coated metal (similar to those used for storage of compressed gas), a vacuum space filled with numerous sheets of highly reflective metalized plastic (for high performance thermal insulation), and a metallic outer jacket. High density of hydrogen storage is key to practical hydrogen-fueled transportation by enabling (1) long-range (500+ km) transportation with high capacity vessels that fit within available spaces in the vehicle, and (2) reduced cost per kilogram of hydrogen stored through reduced need for expensive structural material (carbon fiber composite) necessary to make the vessel. Low temperature of storage also leads to reduced expansion energy (by an order of magnitude or more vs. ambient temperature compressed gas storage), potentially providing important safety advantages. All this is accomplished while simultaneously avoiding fuel venting typical of cryogenic vessels for all practical use scenarios. This dissertation describes the work necessary for developing and demonstrating successive generations of cryogenic pressure vessels demonstrated at Lawrence Livermore National Laboratory. The work included (1) conceptual design, (2) detailed system design (3) structural analysis of cryogenic pressure vessels, (4) thermal analysis of heat transfer through cryogenic supports and vacuum multilayer insulation, and (5) experimental demonstration. Aside from succeeding in demonstrating a hydrogen storage approach that has established all the world records for hydrogen storage on vehicles (longest driving range, maximum hydrogen storage density, and maximum containment of cryogenic hydrogen without venting), the work also demonstrated a methodology for computationally efficient detailed modeling of cryogenic pressure vessels. The work continues with support of the US Department of Energy to demonstrate a new generation of cryogenic vessels anticipated to improve on the hydrogen storage performance figures previously imposed in this project. The author looks forward to further contributing to a future of long-range, inexpensive, and safe zero emissions transportation.

Microvascular changes after vitrectomy with internal limiting membrane peeling: an optical coherence tomography angiography study.

PubMed

Mastropasqua, Leonardo; Borrelli, Enrico; Carpineto, Paolo; Toto, Lisa; Di Antonio, Luca; Mattei, Peter A; Mastropasqua, Rodolfo

2017-06-19

To evaluate superficial capillary plexus (SCP) changes occurring after internal limiting membrane (ILM) peeling for the treatment of idiopathic epiretinal membrane (ERM). A total of 15 eyes of 15 patients affected by idiopathic ERM (eight males and seven females; mean age 59.8 ± 9.6 years) were enrolled in the study. Patients were treated with pars plana vitrectomy followed by ERM and ILM peeling. Subjects were evaluated at baseline and at the week-1 and month-1 follow-up visits. At each visit, patients were evaluated with a complete ophthalmologic evaluation, which included imaging with optical coherence tomography angiography. Overall, the SCP vessel density was 43.0 ± 3.0% at baseline and was stable throughout the follow-up (40.0 ± 4.0% at week-1 and 41.0 ± 4.0% at month-1 follow-up visits; p = 0.087 and p = 0.426, respectively). Nevertheless, the SCP vessel density was reduced at week-1 visit in both the superior and inferior sectors. In these sectors, the superficial vessel density was still reduced at the month-1 follow-up visit. We observed a reduction in the SCP vessel density occurring after pars plana vitrectomy with ILM peeling. The reduction is referred to those areas where other changes (e.g., swelling of the arcuate nerve fiber layer) have been already described. In theory, superficial vessel density modifications may be due to the direct surgical trauma to the inner retina, where the superficial plexus is contained, during the ILM grasping.

Can a Penning ionization discharge simulate the tokamak scrape-off plasma conditions?

NASA Technical Reports Server (NTRS)

Finkenthal, M.; Littman, A.; Stutman, D.; Kovnovich, S.; Mandelbaum, P.; Schwob, J. L.; Bhatia, A. K.

1990-01-01

The tokamak scrape-off (the region between the vacuum vessel wall and the magnetically confined fusion plasma edge), represents a source/sink for the hot fusion plasma. The electron densities and temperatures are in the ranges 10 to the 11th - 10 to the 13th/cu cm and 1-40 eV, respectively (depending on the size, magnetic field intensity and configuration, plasma current, etc). In the work reported, the electron temperature and density have been estimated in a Penning ionization discharge by comparing its spectroscopic emission in the VUV with that predicted by a collisional radiative model. An attempt to directly compare this emission with that of the tokamak edge is briefly described.

SU-C-207-07: Quantification of Coronary Artery Cross-Sectional Area in CT Angiography Using Integrated Density: A Phantom Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, T; Ding, H; Torabzadeh, M

2015-06-15

Purpose: To investigate the feasibility of quantifying the cross-sectional area (CSA) of coronary arteries using integrated density in a physics-based model with a phantom study. Methods: In this technique the total integrated density of the object as compared with its local background is measured so it is possible to account for the partial volume effect. The proposed method was compared to manual segmentation using CT scans of a 10 cm diameter Lucite cylinder placed inside a chest phantom. Holes with cross-sectional areas from 1.4 to 12.3 mm{sup 2} were drilled into the Lucite and filled with iodine solution, producing amore » contrast-to-noise ratio of approximately 26. Lucite rods 1.6 mm in diameter were used to simulate plaques. The phantom was imaged with and without the Lucite rods placed in the holes to simulate diseased and normal arteries, respectively. Linear regression analysis was used, and the root-mean-square deviations (RMSD) and errors (RMSE) were computed to assess the precision and accuracy of the measurements. In the case of manual segmentation, two readers independently delineated the lumen in order to quantify the inter-reader variability. Results: The precision and accuracy for the normal vessels using the integrated density technique were 0.32 mm{sup 2} and 0.32 mm{sup 2}, respectively. The corresponding results for the manual segmentation were 0.51 mm{sup 2} and 0.56 mm{sup 2}. In the case of diseased vessels, the precision and accuracy of the integrated density technique were 0.46 mm{sup 2} and 0.55 mm{sup 2}, respectively. The corresponding results for the manual segmentation were 0.75 mm{sup 2} and 0.98 mm{sup 2}. The mean percent difference for the two readers was found to be 8.4%. Conclusion: The CSA based on integrated density had improved precision and accuracy as compared with manual segmentation in a Lucite phantom. The results indicate the potential for using integrated density to improve CSA measurements in CT angiography.« less

Dietary antioxidants preserve endothelium-dependent vessel relaxation in cholesterol-fed rabbits.

PubMed Central

Keaney, J F; Gaziano, J M; Xu, A; Frei, B; Curran-Celentano, J; Shwaery, G T; Loscalzo, J; Vita, J A

1993-01-01

Recent evidence suggests that dietary therapy with lipid-soluble antioxidants may be beneficial for patients with atherosclerotic vascular disease but the potential mechanism(s) for these observations remain obscure. Abnormalities in endothelium-dependent control of vascular tone develop early in the course of atherosclerosis and may result from oxidative modification of low density lipoproteins. We examined the role of dietary antioxidants in preserving normal endothelial cell vasodilator function in cholesterol-fed rabbits with particular attention to possible effects on serum lipoproteins, low density lipoprotein oxidation, and atherogenesis. Male New Zealand White rabbits were fed diets containing no additive (controls), 1% cholesterol (cholesterol group), or 1% cholesterol chow supplemented with either beta-carotene (0.6 g/kg of chow) or alpha-tocopherol (1000 international units/kg of chow) for a 28-day period. After dietary therapy, thoracic aortae were harvested for assay of vascular function and for pathologic examination and tissue antioxidant levels. Compared to controls, acetylcholine- and A23187-mediated endothelium-dependent relaxations were significantly impaired in vessels from the cholesterol group (P < 0.001), whereas vessels from animals treated with beta-carotene or alpha-tocopherol demonstrated normal endothelium-dependent arterial relaxation. Preservation of endothelial function was associated with vascular incorporation of alpha-tocopherol and beta-carotene but was unrelated to plasma lipoprotein levels, smooth muscle cell function, or the extent of atherosclerosis. Increased low density lipoprotein resistance to ex vivo copper-mediated oxidation was observed only in the alpha-tocopherol group. Our results suggest that dietary antioxidants may benefit patients with atherosclerosis by preserving endothelial vasodilator function through a mechanism related to vascular tissue antioxidant content and not reflected by assay of low density lipoprotein resistance to ex vivo oxidation. PMID:8265642

[The rule of lymphatic formation in rabbit VX2 supraglottic carcinoma model with lymph node metastasis].

PubMed

Zhang, Pin; Ji, Wenyue; Zhang, Xiangbo

2012-02-01

Establishment of transplanted model of VX2 supraglottic carcinoma in rabbits and investigation the rule of lymphatic vessels formation. After establishment of VX2 tumor-bearing rabbits, the carcinoma tissues were transplanted into the operculum laryngis submucosa in sixty New-Zealand white rabbits to establish transplanted tumor model. Vascular endothelial growth factor-3 (VEGFR-3) label staining was performed to observe lymphatic vessels. Number density, volume density of lymphatics periphery region of carcinoma, normal region and centre region were measured using computer image analysis system. There was no lymphatic vessels in carcinomatous centre region,but the lymphatic vessels number density, volume density in periphery region was much more than normal region. Their cavities were dilated. The discrepancy had statistical significance (P<0.01). The rule of lymphatic formation in rabbit VX2 supraglottic carcinoma model mimesis rule of lymphatic formation anthropo- supraglottic carcinoma. Lymphatic multiplication and dilation at periphery region of carcinoma is associated with lymph node metastasis. Evaluation of it at periphery region of carcinoma may be useful in predicting lymph node metastasis in patients with supraglottic carcinoma. This conclusion provides theoretical basis for utility of the anti-tumor medicines which inhibit lymphatic formation in animal model.

Inferred fish behavior its implications for hydroacoustic surveys in nearshore habitats

USGS Publications Warehouse

DuFour, Mark R.; Mayer, Christine M.; Qian, Song S.; Vandergoot, Christopher; Kraus, Richard T.; Kocovsky, Patrick; Warner, David M.

2018-01-01

Population availability and vessel avoidance effects on hydroacoustic abundance estimates may be scale dependent; therefore, it is important to evaluate these biases across systems. We performed an inter-ship comparison survey to determine the effect of vessel size, day-night period, depth, and environmental gradients on walleye (Sander vitreus) density estimates in Lake Erie, an intermediate-scaled system. Consistent near-bottom depth distributions coupled with horizontal fish movements relative to vessel paths indicated avoidance behavior contributed to higher walleye densities from smaller vessels in shallow water (i.e., <15 m), although the difference decreased with increasing depth. Diel bank migrations in response to seasonally varying onshore-to-offshore environmental gradients likely contributed to day-night differences in densities between sampling locations and seasons. Spatial and unexplained variation accounted for a high proportion of total variation; however, increasing sampling intensity can mitigate effects on precision. Therefore, researchers should minimize systematic avoidance and availability related biases (i.e., vessel and day-night period) to improve population abundance estimates. Quantifying availability and avoidance behavior effects and partitioning sources of variation provides informed flexibility for designing future hydroacoustic surveys in shallow-water nearshore environments.

How to quantify conduits in wood?

PubMed

Scholz, Alexander; Klepsch, Matthias; Karimi, Zohreh; Jansen, Steven

2013-01-01

Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology.

Radiation-induced impairment in lung lymphatic vasculature.

PubMed

Cui, Ye; Wilder, Julie; Rietz, Cecilia; Gigliotti, Andrew; Tang, Xiaomeng; Shi, Yuanyuan; Guilmette, Raymond; Wang, Hao; George, Gautam; Nilo de Magaldi, Eduarda; Chu, Sarah G; Doyle-Eisele, Melanie; McDonald, Jacob D; Rosas, Ivan O; El-Chemaly, Souheil

2014-12-01

The lymphatic vasculature has been shown to play important roles in lung injury and repair, particularly in lung fibrosis. The effects of ionizing radiation on lung lymphatic vasculature have not been previously reported. C57Bl/6 mice were immobilized in a lead shield exposing only the thoracic cavity, and were irradiated with a single dose of 14 Gy. Animals were sacrificed and lungs collected at different time points (1, 4, 8, and 16 weeks) following radiation. To identify lymphatic vessels in lung tissue sections, we used antibodies that are specific for lymphatic vessel endothelial receptor 1 (LYVE-1), a marker of lymphatic endothelial cells (LEC). To evaluate LEC cell death and oxidative damage, lung tissue sections were stained for LYVE-1 and with TUNEL staining, or 8-oxo-dG respectively. Images were imported into ImageJ v1.36b and analyzed. Compared to a non-irradiated control group, we observed a durable and progressive decrease in the density, perimeter, and area of lymphatic vessels over the study period. The decline in the density of lymphatic vessels was observed in both subpleural and interstitial lymphatics. Histopathologically discernible pulmonary fibrosis was not apparent until 16 weeks after irradiation. Furthermore, there was significantly increased LEC apoptosis and oxidative damage at one week post-irradiation that persisted at 16 weeks. There is impairment of lymphatic vasculature after a single dose of ionizing radiation that precedes architectural distortion and fibrosis, suggesting important roles for the lymphatic circulation in the pathogenesis of the radiation-induced lung injury.

Wood traits related to size and life history of trees in a Panamanian rainforest.

PubMed

Hietz, Peter; Rosner, Sabine; Hietz-Seifert, Ursula; Wright, S Joseph

2017-01-01

Wood structure differs widely among tree species and species with faster growth, higher mortality and larger maximum size have been reported to have fewer but larger vessels and higher hydraulic conductivity (Kh). However, previous studies compiled data from various sources, often failed to control tree size and rarely controlled variation in other traits. We measured wood density, tree size and vessel traits for 325 species from a wet forest in Panama, and compared wood and leaf traits to demographic traits using species-level data and phylogenetically independent contrasts. Wood traits showed strong phylogenetic signal whereas pairwise relationships between traits were mostly phylogenetically independent. Trees with larger vessels had a lower fraction of the cross-sectional area occupied by vessel lumina, suggesting that the hydraulic efficiency of large vessels permits trees to dedicate a larger proportion of the wood to functions other than water transport. Vessel traits were more strongly correlated with the size of individual trees than with maximal size of a species. When individual tree size was included in models, Kh scaled positively with maximal size and was the best predictor for both diameter and biomass growth rates, but was unrelated to mortality. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Starch Hydrolysis and Vessel Occlusion Related to Wilt Symptoms in Olive Stems of Susceptible Cultivars Infected by Verticillium dahliae

PubMed Central

Trapero, Carlos; Alcántara, Esteban; Jiménez, Jaime; Amaro-Ventura, María C.; Romero, Joaquín; Koopmann, Birger; Karlovsky, Petr; von Tiedemann, Andreas; Pérez-Rodríguez, Mario; López-Escudero, Francisco J.

2018-01-01

This study investigated starch content, amount of pathogen DNA and density of occluded vessels in healthy and Verticillium dahliae infected olive shoots and stems. Starch hydrolysis is considered a mechanism to refill xylem vessels that suffered cavitation by either, drought conditions or pathogen infections. The main objective of this work was to evaluate this mechanism in olive plants subjected to V. dahliae infection or to drought conditions, in order to know the importance of cavitation in the development of wilting symptoms. In initial experiments starch content in the shoots was studied in trees of cultivars differing in the level of resistance growing in fields naturally infested with V. dahliae. The starch content, esteemed by microscopic observation of stem transversal sections stained with lugol, decreased with the level of symptom severity. Results were confirmed in a new experiment developed with young plants of cultivars ‘Picual’ (highly susceptible), ‘Arbequina’ (moderately susceptible) and ‘Frantoio’ (resistant), growing in pots under greenhouse conditions, either inoculated or not with V. dahliae. In this experiment, the pathogen DNA content, quantified by real-time PCR, and the density of occluded vessels, recorded by microscopic observations of transversal sections stained with toluidine blue, were related to the symptoms severity caused by the pathogen. Finally, a drought experiment was established with young plants of the cultivar ‘Picual’ grown in pots under greenhouse conditions in order to compare the effects caused by water deficit with those caused by the pathogen infection. In both cases, results show that starch hydrolysis occurred, what indirectly evidence the importance of xylem cavitation in the development of the symptoms caused by V. dahliae but in the water stressed plants no vessel occlusion was detected. PMID:29445388

Cell culture for three-dimensional modeling in rotating-wall vessels: an application of simulated microgravity

NASA Technical Reports Server (NTRS)

Schwarz, R. P.; Goodwin, T. J.; Wolf, D. A.

1992-01-01

High-density, three-dimensional cell cultures are difficult to grow in vitro. The rotating-wall vessel (RWV) described here has cultured BHK-21 cells to a density of 1.1 X 10(7) cells/ml. Cells on microcarriers were observed to grow with enhanced bridging in this batch culture system. The RWV is a horizontally rotated tissue culture vessel with silicon membrane oxygenation. This design results in a low-turbulence, low-shear cell culture environment with abundant oxygenation. The RWV has the potential to culture a wide variety of normal and neoplastic cells.

In situ cannulation, microgrid follow-up and low-density plating provide first passage endothelial cell masscultures for in vitro lining.

PubMed

Zilla, P; Fasol, R; Dudeck, U; Siedler, S; Preiss, P; Fischlein, T; Müller-Glauser, W; Baitella, G; Sanan, D; Odell, J

1990-08-01

A rapid and reliable harvest and culture technique was developed to provide a sufficient number of autologous endothelial cells for the confluent in vitro lining of cardiovascular prostheses. Enzymatic endothelial cell detachment was achieved by the in situ application of collagenase to short vessel segments. This harvest technique resulted in a complete lack of contaminating smooth muscle cells in all of 124 cultures from nonhuman primates and 13 cultures from human adults. The use of a microgrid technique enabled the daily in situ quantification of available endothelial cells. To assess ideal plating densities after passage the population doubling time was continuously related to the cell density. Surprisingly, a low plating density of 1.5 X 10(3) endothelial cells/cm2 achieved 43% shorter cell cycles than the usual plating density of 1.0 X 10(4) endothelial cells/cm2. Moreover, low density plating enabled mass cultures after one single cell passage, thereby reducing the cell damaging effect of trypsin. When the growth characteristics of endothelial cells from five anatomically different vessel sites were compared, the external jugular vein--which would be easily accessible and dispensable in each patient--proved to be an excellent source for endothelial cell cultures. By applying in situ administration of collagenase, low density plating and microgrid follow-up to adult human saphenous vein endothelial cells, 14,000,000 first passage endothelial cells--sufficient for the in vitro lining of long vascular prostheses--were obtained 26.2 days after harvest. (95% confidence interval:22.3 to 32.2 days).

A strain energy filter for 3D vessel enhancement with application to pulmonary CT images.

PubMed

Xiao, Changyan; Staring, Marius; Shamonin, Denis; Reiber, Johan H C; Stolk, Jan; Stoel, Berend C

2011-02-01

The traditional Hessian-related vessel filters often suffer from detecting complex structures like bifurcations due to an over-simplified cylindrical model. To solve this problem, we present a shape-tuned strain energy density function to measure vessel likelihood in 3D medical images. This method is initially inspired by established stress-strain principles in mechanics. By considering the Hessian matrix as a stress tensor, the three invariants from orthogonal tensor decomposition are used independently or combined to formulate distinctive functions for vascular shape discrimination, brightness contrast and structure strength measuring. Moreover, a mathematical description of Hessian eigenvalues for general vessel shapes is obtained, based on an intensity continuity assumption, and a relative Hessian strength term is presented to ensure the dominance of second-order derivatives as well as suppress undesired step-edges. Finally, we adopt the multi-scale scheme to find an optimal solution through scale space. The proposed method is validated in experiments with a digital phantom and non-contrast-enhanced pulmonary CT data. It is shown that our model performed more effectively in enhancing vessel bifurcations and preserving details, compared to three existing filters. Copyright © 2010 Elsevier B.V. All rights reserved.

Vascular pericyte density and angiogenesis associated with adenocarcinoma of the prostate.

PubMed

Killingsworth, Murray C; Wu, Xiaojuan

2011-01-01

Angiogenesis facilitates metabolism, proliferation and metastasis of adenocarcinoma cells in the prostate, as without the development of new vasculature tumor growth cannot be sustained. However, angiogenesis is variable with the well-known phenomenon of vascular 'hotspots' seen associated with viable tumor cell mass. With the recent recognition of pericytes as molecular regulators of angiogenesis, we have examined the interaction of these cells in actively growing new vessels. Pericyte interactions with developing new vessels were examined using transmission electron microscopy. Pericyte distribution was mapped from α-SMA+ immunostained histological sections and quantified using image analysis. Data was obtained from peripheral and more central regions of 27 cases with Gleason scores of 4-9. Pericyte numbers were increased around developing new vessel sprouts at sites of luminal maturation. Numbers were reduced around the actively growing tips of migrating endothelial cells and functional new vessels. Tumor regions internal to a 500-μm peripheral band showed higher microvessel pericyte density than the peripheral region. Pericytes were found to be key cellular components of developing new vessels in adenocarcinoma of the prostate. Their numbers increased at sites of luminal maturation with these cells displaying an activated phenotype different to quiescent pericytes. Increased pericyte density was found internal to the peripheral region, suggesting more mature vessels lie more centrally. Copyright © 2011 S. Karger AG, Basel.

Histomorphometric comparative study of blood vessels and their pattern in follicular cyst, odontogenic keratocyst, and ameloblastoma.

PubMed

Seifi, Safora; Feizi, Farideh; Khafri, Thoraya; Aram, Mehrdad

2013-03-01

The present study aimed at assessment and histomorphometric analysis of intratumoral and peritumoral (cystic) blood vessels in odontogenic lesions and their pattern on their clinical behavior by immunohistochemistry and morphometry. In a descriptive and analytical cross-sectional study, 45 paraffin blocks of ameloblastoma, odontogenic keratocyst, and follicular cyst were selected and stained immunohistochemically for CD34. In each slide, images of 3 microscopic fields with the highest microvessel density in intratumoral and peritumoral (cystic) areas were captured at 40× magnification with attached camera system. Inner vascular diameter (IVD) and outer vascular diameter (OVD), cross-sectional area (CSA), and the wall thickness (WT) of the vessels were measured with Motic Plus 2 software. The vascular pattern in odontogenic lesions was analyzed. Outer vascular diameter, IVD, and CSA of the vessels in peritumoral (cystic) areas were greater in ameloblastoma than keratocyst (P = 0.001) and follicular cyst (P < 0.001). However, WT of the blood vessels did not show any significant statistical difference among the 3 odontogenic lesions (P = 0.05). The differences in OVD, IVD (P = 0.8), CSA (P = 0.6), and WT (P = 0.4) of the blood vessels in intratumoral (cystic) areas were not statistically significant. The blood vessel pattern was circumferential in ameloblastoma, and it was directional in keratocyst and follicular cyst. Morphometric specifications of blood vessels (IVD, OVD, CSA) and their pattern in peritumoral (cystic) areas may influence the aggressive clinical behavior of ameloblastoma in comparison with keratocyst and follicular cyst.

High-Aspect-Ratio Rotating Cell-Culture Vessel

NASA Technical Reports Server (NTRS)

Wolf, David A.; Sams, Clarence; Schwarz, Ray P.

1992-01-01

Cylindrical rotating cell-culture vessel with thin culture-medium layer of large surface area provides exchange of nutrients and products of metabolism with minimal agitation. Rotation causes averaging of buoyant forces otherwise separating components of different densities. Vessel enables growth of cells in homogeneous distribution with little agitation and little shear stress.

Broad Anatomical Variation within a Narrow Wood Density Range—A Study of Twig Wood across 69 Australian Angiosperms

PubMed Central

Ziemińska, Kasia; Westoby, Mark; Wright, Ian J.

2015-01-01

Objectives Just as people with the same weight can have different body builds, woods with the same wood density can have different anatomies. Here, our aim was to assess the magnitude of anatomical variation within a restricted range of wood density and explore its potential ecological implications. Methods Twig wood of 69 angiosperm tree and shrub species was analyzed. Species were selected so that wood density varied within a relatively narrow range (0.38–0.62 g cm-3). Anatomical traits quantified included wood tissue fractions (fibres, axial parenchyma, ray parenchyma, vessels, and conduits with maximum lumen diameter below 15 μm), vessel properties, and pith area. To search for potential ecological correlates of anatomical variation the species were sampled across rainfall and temperature contrasts, and several other ecologically-relevant traits were measured (plant height, leaf area to sapwood area ratio, and modulus of elasticity). Results Despite the limited range in wood density, substantial anatomical variation was observed. Total parenchyma fraction varied from 0.12 to 0.66 and fibre fraction from 0.20 to 0.74, and these two traits were strongly inversely correlated (r = -0.86, P < 0.001). Parenchyma was weakly (0.24 ≤|r|≤ 0.35, P < 0.05) or not associated with vessel properties nor with height, leaf area to sapwood area ratio, and modulus of elasticity (0.24 ≤|r|≤ 0.41, P < 0.05). However, vessel traits were fairly well correlated with height and leaf area to sapwood area ratio (0.47 ≤|r|≤ 0.65, all P < 0.001). Modulus of elasticity was mainly driven by fibre wall plus vessel wall fraction rather than by the parenchyma component. Conclusions Overall, there seem to be at least three axes of variation in xylem, substantially independent of each other: a wood density spectrum, a fibre-parenchyma spectrum, and a vessel area spectrum. The fibre-parenchyma spectrum does not yet have any clear or convincing ecological interpretation. PMID:25906320

Can forest dieback and tree death be predicted by prior changes in wood anatomy?

NASA Astrophysics Data System (ADS)

Colangelo, Michele; Julio Camarero, Jesus; De Micco, Veronica; Borghetti, Marco; Gentilesca, Tiziana; Sanchez-Salguero, Raul; Ripullone, Francesco

2017-04-01

Climate warming is expected to amplify drought stress resulting in more intense and widespread dieback episodes and increasing mortality rates. Studies on quantitative wood anatomy and dendrochronology have demonstrated their potential to supply useful information on the causes of tree decline, although this approach is basically observational and retrospective. Moreover, the long-term reconstruction of wood anatomical features, strictly linked to the evolution of xylem anatomy plasticity through time, allow investigating hydraulic adjustments of trees. In this study, we analyzed wood-anatomical variables in two Italian oak forests where recent episodes of dieback and mortality have been reported. We analyzed in coexisting now-dead and living trees the following wood-anatomical variables: annual tree-ring area, earlywood (EW) and latewood (LW) areas, absolute and relative (%) areas occupied by vessels in the EW and LW, EW and LW vessel areas, EW and LW vessel density and vessel diameter classification. We also calculated the hydraulic diameter (Dh) for all vessels measured within each ring by weighting individual conduit diameters to correspond to the average Hagen-Poiseuille lumen theoretical hydraulic conductivity for a vessel size. Wood-anatomical analyses showed that declining and dead trees were more sensitive to drought stress compared to non declining trees, indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. We discuss the results and implications focusing on those proved more sensitive to the phenomena of decline and mortality.

Oscillation of Angiogenesis with Vascular Dropout in Diabetic Retinopathy by VESsel GENeration Analysis (VESGEN)

NASA Technical Reports Server (NTRS)

Parsons-Wingerter, Patricia; Radbakrishnan, Krisbnan; Vickerman, Mary B.; Kaiser, Peter K.

2010-01-01

PURPOSE. Vascular dropout and angiogenesis are hallmarks of the progression of diabetic retinopathy (DR). However, current evaluation of DR relies on grading of secondary vascular effects, such as microaneurysms and hemorrhages, by clinical examination instead of by evaluation of actual vascular changes. The purpose of this study was to map and quantify vascular changes during progression of DR by VESsel GENeration Analysis (VESGEN). METHODS. In this prospective cross-sectional study, 15 eyes with DR were evaluated with fluorescein angiography (FA) and color fundus photography, and were graded using modified Early Treatment Diabetic Retinopathy Study criteria. FA images were separated by semiautomatic image processing into arterial and venous trees. Vessel length density (L(sub v)), number density (N(sub v)), and diameter (D(sub v)) were analyzed in a masked fashion with VESGEN software. Each vascular tree was automatically segmented into branching generations (G(sub 1)...G(sub 8) or G(sub 9)) by vessel diameter and branching. Vascular remodeling status (VRS) for N(sub v) and L(sub v) was graded 1 to 4 for increasing severity of vascular change. RESULTS. By N(sub v) and L(sub v), VRS correlated significantly with the independent clinical diagnosis of mild to proliferative DR (13/15 eyes). N(sub v) and L(sub v) of smaller vessels (G(sub >=6) increased from VRS1 to VRS2 by 2.4 X and 1.6 X, decreased from VRS2 to VRS3 by 0.4 X and 0.6X, and increased from VRS3 to VRS4 by 1.7 X and 1.5 X (P < 0.01). Throughout DR progression, the density of larger vessels (G(sub 1-5)) remained essentially unchanged, and D(sub v1-5) increased slightly. CONCLUSIONS. Vessel density oscillated with the progression of DR. Alternating phases of angiogenesis/neovascularization and vascular dropout were dominated first by remodeling of arteries and subsequently by veins.

Generational Analysis Reveals that TGF-Beta1 Inhibits the Rate of Angiogenesis in Vivo by Selective Decrease in the Number of New Vessels

NASA Technical Reports Server (NTRS)

Parsons-Wingerter, Patricia; Elliott, Katherine E.; Farr, Andrew G.; Radhakrishnan, Krishnan; Clark, John I.; Sage, E. Helene

2000-01-01

Quantitative analysis of vascular generational branching demonstrated that transforming growth factor-beta1 (TGF-beta1), a multifunctional cytokine and angiogenic regulator, strongly inhibited angiogenesis in the arterial tree of the developing quail chorioallantoic membrane (CAM) by inhibition of the normal increase in the number of new, small vessels. The cytokine was applied uniformly in solution at embryonic day 7 (E7) to the CAMs of quail embryos cultured in petri dishes. After 24 h the rate of arterial growth was inhibited by as much as 105% as a function of increasing TGF-beta1 concentration. Inhibition of the rate of angiogenesis in the arterial tree by TGF-beta1 relative to controls was measured in digital images by three well-correlated, computerized methods. The first computerized method, direct measurement by the computer code VESGEN of vascular morphological parameters according to branching generations G(sub 1) through G(sub greater than or equal to 5), revealed that TGF-beta1 selectively inhibited the increase in the number density of small vessels, N(sub v greater than or equal to 5), (382 plus or minus 85 per square centimeter) for specimens treated with 1 microgram TGF-beta1/CAM for 24 h, compared to 583 plus or minus 99 per square centimeter for controls), but did not significantly affect other parameters such as average vessel length or vessel diameter. The second and third methods, the fractal dimension (D(sub f)) and grid intersection (rho (sub v)), are statistical descriptors of spatial pattern and density. According to D(sub f) and rho(sub v), arterial density increased in control specimens from 1.382 plus or minus 0.007 and 662 plus or minus 52 per square centimeters at E7 (0 h) to 1.439 plus or minus 0.013 and 884 plus or minus 55 per square centimeters at E8 (24 h), compared to 1.379 plus or minus 0.039 and 650 plus or minus 111 per square centimeter for specimens treated with 1 microgram TGF-beta1/CAM for 24 h. TGF-beta1 therefore regulates vascular pattern and the rate of angiogenesis in a unique fingerprint manner, as do other major angiogenic regulators that include VEGF, FGF-2 (bFGF), and angiostatin. TGF-beta1 did not stimulate angiogenesis significantly at low cytokine concentrations, which suggests that this quail CAM model of angiogenesis is not associated with an inflammatory response.

Effect of asymmetrical eddy currents on magnetic diagnosis signals for equilibrium reconstruction in the Sino-UNIted Spherical Tokamak.

PubMed

Jiang, Y Z; Tan, Y; Gao, Z; Wang, L

2014-11-01

The vacuum vessel of Sino-UNIted Spherical Tokamak was split into two insulated hemispheres, both of which were insulated from the central cylinder. The eddy currents flowing in the vacuum vessel would become asymmetrical due to discontinuity. A 3D finite elements model was applied in order to study the eddy currents. The modeling results indicated that when the Poloidal Field (PF) was applied, the induced eddy currents would flow in the toroidal direction in the center of the hemispheres and would be forced to turn to the poloidal and radial directions due to the insulated slit. Since the eddy currents converged on the top and bottom of the vessel, the current densities there tended to be much higher than those in the equatorial plane were. Moreover, the eddy currents on the top and bottom of vacuum vessel had the same direction when the current flowed in the PF coils. These features resulted in the leading phases of signals on the top and bottom flux loops when compared with the PF waveforms.

A Comparative Study of Collagen Matrix Density Effect on Endothelial Sprout Formation Using Experimental and Computational Approaches.

PubMed

Shamloo, Amir; Mohammadaliha, Negar; Heilshorn, Sarah C; Bauer, Amy L

2016-04-01

A thorough understanding of determining factors in angiogenesis is a necessary step to control the development of new blood vessels. Extracellular matrix density is known to have a significant influence on cellular behaviors and consequently can regulate vessel formation. The utilization of experimental platforms in combination with numerical models can be a powerful method to explore the mechanisms of new capillary sprout formation. In this study, using an integrative method, the interplay between the matrix density and angiogenesis was investigated. Owing the fact that the extracellular matrix density is a global parameter that can affect other parameters such as pore size, stiffness, cell-matrix adhesion and cross-linking, deeper understanding of the most important biomechanical or biochemical properties of the ECM causing changes in sprout morphogenesis is crucial. Here, we implemented both computational and experimental methods to analyze the mechanisms responsible for the influence of ECM density on the sprout formation that is difficult to be investigated comprehensively using each of these single methods. For this purpose, we first utilized an innovative approach to quantify the correspondence of the simulated collagen fibril density to the collagen density in the experimental part. Comparing the results of the experimental study and computational model led to some considerable achievements. First, we verified the results of the computational model using the experimental results. Then, we reported parameters such as the ratio of proliferating cells to migrating cells that was difficult to obtain from experimental study. Finally, this integrative system led to gain an understanding of the possible mechanisms responsible for the effect of ECM density on angiogenesis. The results showed that stable and long sprouts were observed at an intermediate collagen matrix density of 1.2 and 1.9 mg/ml due to a balance between the number of migrating and proliferating cells. As a result of weaker connections between the cells and matrix, a lower collagen matrix density (0.7 mg/ml) led to unstable and broken sprouts. However, higher matrix density (2.7 mg/ml) suppressed sprout formation due to the high level of matrix entanglement, which inhibited cell migration. This study also showed that extracellular matrix density can influence sprout branching. Our experimental results support this finding.

Radial Peripapillary Capillary Network in Patients with Retinitis Pigmentosa: An Optical Coherence Tomography Angiography Study.

PubMed

Mastropasqua, Rodolfo; Borrelli, Enrico; Agnifili, Luca; Toto, Lisa; Di Antonio, Luca; Senatore, Alfonso; Palmieri, Michele; D'Uffizi, Alessandro; Carpineto, Paolo

2017-01-01

To investigate radial peripapillary capillary (RPC) network in patients affected by retinitis pigmentosa (RP). Eleven patients (22 eyes) with previous diagnosis of RP and 16 age-matched healthy subjects (16 eyes) were enrolled. The diagnosis of RP was made based on both clinical features and electrophysiological examination. All patients underwent a complete ophthalmologic examination, including optical coherence tomography angiography and visual field (VF). The primary outcomes were the RPC vessel density in the peripapillary and disk areas; the secondary outcomes were the peripapillary retinal nerve fiber layer (RNFL) thickness and the mean defect at VF. A total of 19 eyes of 11 RP patients (5 males, 6 females) and 16 eyes of 16 healthy subjects (10 males, 6 females) were included for the analysis. RPC vessel density in the disk area was 46.5 ± 7.1% in the RP group and 45.4 ± 10.6% in the control group ( p  = 0.754). RPC vessel density in the peripapillary area was significantly reduced in the RP group after the comparison with the control group (52.5 ± 5.0 and 57.2 ± 5.1%, respectively, p  = 0.011). RNFL thickness was 85.9 ± 20.4 μm in the RP group and 104.0 ± 6.4 μm in the control group ( p  = 0.002). RPC vessel density was significantly correlated with RNFL thickness values in RP patients, both in the disk and in the peripapillary area (Rho = 0.599 and p  = 0.007 in the disk area, Rho = 0.665 and p  = 0.002 in the peripapillary area, respectively). We showed that density of RPC is reduced in these patients in the peripapillary area. Moreover, the RPC vessel density correlates with the RNFL thickness.

Age-Related Alterations in the Retinal Microvasculature, Microcirculation, and Microstructure

PubMed Central

Wei, Yantao; Jiang, Hong; Shi, Yingying; Qu, Dongyi; Gregori, Giovanni; Zheng, Fang; Rundek, Tatjana; Wang, Jianhua

2017-01-01

Purpose To characterize age-related alterations in the retinal microcirculation, microvascular network, and microstructure in healthy subjects. Methods Seventy-four healthy subjects aged from 18 to 82 years were recruited and divided into four age groups (G1 with age <35 years, G2 with age 35 ∼ 49 years, G3 with age 50 ∼ 64 years, and G4 with age ≥65 years). Custom ultra-high resolution optical coherence tomography (UHR-OCT) was used to acquire six intraretinal layers of the macula. OCT angiography (OCTA) was used to image the retinal microvascular network. The retinal blood flow velocity (BFV) was measured using a Retinal Function Imager (RFI). Results Compared to G1, G2 had significant thinning of the retinal nerve fiber layer (RNFL) (P < 0.05), while G3 had thinning of the RNFL and ganglion cell and inner plexiform layer (GCIPL) (P < 0.05), in addition to thickening of the outer plexiform layer (OPL) and photoreceptor layer (PR) (P < 0.05). G4 had loss in retinal vessel density, thinning in RNFL and GCIPL, and decrease in venular BFV, in addition to thickening of the OPL and PR (P < 0.05). Age was negatively related to retinal vessel densities, the inner retinal layers, and venular BFV (P < 0.05). By contrast, age was positively related to OPL and PR (P < 0.05). Conclusions During aging, decreases in retinal vessel density, inner retinal layer thickness, and venular BFV were evident and impacted each other as observed by simultaneous changes in multiple retinal components. PMID:28744554

Launch Conditions Might Affect the Formation of Blood Vessel in the Quail Chorioallantoic Membrane

NASA Technical Reports Server (NTRS)

Henry, M. K.; Unsworth, B. R.; Sychev, B. R.; Guryeva, T. S.; Dadasheva, O. A.; Piert, S. J.; Lagel, K. E.; Dubrovin, L. C.; Jahns, G. C.; Boda, K.;

Apelin as a marker for monitoring the tumor vessel normalization window during antiangiogenic therapy.

PubMed

Zhang, Li; Takara, Kazuhiro; Yamakawa, Daishi; Kidoya, Hiroyasu; Takakura, Nobuyuki

2016-01-01

Antiangiogenic agents transiently normalize tumor vessel structure and improve vessel function, thereby providing a window of opportunity for enhancing the efficacy of chemotherapy or radiotherapy. Currently, there are no reliable predictors or markers reflecting this vessel normalization window during antiangiogenic therapy. Apelin, the expression of which is regulated by hypoxia, and which has well-described roles in tumor progression, is an easily measured secreted protein. Here, we show that apelin can be used as a marker for the vessel normalization window during antiangiogenic therapy. Mice bearing s.c. tumors resulting from inoculation of the colon adenocarcinoma cell line HT29 were treated with a single injection of bevacizumab, a mAb neutralizing vascular endothelial growth factor. Tumor growth, vessel density, pericyte coverage, tumor hypoxia, and small molecule delivery were determined at four different times after treatment with bevacizumab (days 1, 3, 5, and 8). Tumor growth and vessel density were significantly reduced after bevacizumab treatment, which also significantly increased tumor vessel maturity, and improved tumor hypoxia and small molecule delivery between days 3 and 5. These effects abated by day 8, suggesting that a time window for vessel normalization was opened between days 3 and 5 during bevacizumab treatment in this model. Apelin mRNA expression and plasma apelin levels decreased transiently at day 5 post-treatment, coinciding with vessel normalization. Thus, apelin is a potential indicator of the vessel normalization window during antiangiogenic therapy. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Effects of environmental enrichment on blood vessels in the optic tract of malnourished rats: A morphological and morphometric analysis.

PubMed

Barbosa, Everton Horiquini; Soares, Roberto Oliveira; Braga, Natália Nassif; Almeida, Sebastião de Sousa; Lachat, João-José

2016-06-01

This study aimed to compare the effects of environmental enrichment in nourished (on a diet containing 16% protein) and malnourished (on a diet containing 6% protein) rats during the critical period of brain development, specifically focusing on the optic nerve. By means of morphologic and morphometric assessment of the optic nerve, we analyzed the changes caused by diet and stimulation (environmental enrichment) on postnatal day 35, a time point ideal for such morphological analysis since developmental processes are considered complete at this age. Malnourished animals presented low body and brain weights and high body-to-brain weight ratio compared to well-nourished rats. Furthermore, malnourished animals showed morphological changes in the optic nerve such as edema and vacuolization characterized by increased interstitial space. The malnourished-stimulated group presented lesions characteristic of early protein malnutrition but were milder than lesions exhibited by malnourished-non-stimulated group. The morphometric analysis revealed no difference in glial cell density between groups, but there was significantly higher blood vessel density in the stimulated rats, independent of their nutritional condition. Our data indicate that protein malnutrition imposed during the critical period of brain development alters the cytoarchitecture of the optic nerve. In addition, we affirm that a 1-hour exposure to an enriched environment everyday was sufficient for tissue preservation in rats maintained on a low-protein diet. This protective effect might be related to angiogenesis, as confirmed by the increased vascular density observed in morphometric analyses.

Potential role of pre-existing blood vessels for vascularization and mineralization of osteochondral grafts: an intravital microscopic study in mice.

PubMed

Rothenfluh, Dominique A; Demhartner, Thomas J; Fraitzl, Christian R; Cecchini, Marco G; Ganz, Reinhold; Leunig, Michael

2004-06-01

The aim of this study was to develop an experimental model that allows to elude the potential role of the preexisting graft microvasculature for vascularization and mineralization of osteochondral grafts. For that purpose, the II-IV metatarsals of fetal DDY-mice known to be nonvascularized at day 16 of gestation (M16) but vascularized at day 18 (M18) were freshly transplanted into dorsal skin fold chambers of adult DDY mice. Using intravital microscopy angiogenesis, leukocyte-endothelium interaction and mineralization were assessed for 12 days. Angiogenesis occurred at 32 hours in M18, but not before 57 hours in M16 (p = 0.002), with perfusion of these vessels at 42 hours (p = 0.005) and 65 hours (p = 0.1), respectively. Vessels reached a density three times as high as that of the recipient site at day 6, remaining constant until day 12 in M18, whereas in M16 vascular density increased from day 6 and reached that of M18 at day 12 (p = 0.04). Leukocyte-endothelium interaction showed sticker counts elevated by a factor of 4-5 in M18 as compared to M16. Mineralization of osteochondral grafts did not differ between M16 and M18, which significantly increased in both groups throughout the observation period. We propose the faster kinetics in the angiogenic response to M18 and the elevated counts of sticking leukocytes to rest on the potential of establishing end-to-end anastomoses (inosculation) of the vascularized graft with recipient vessels.

[Comparative ultrastructural study of parotid gland, lacrimal gland and pituitary gland between miniature pig and mouse].

PubMed

Yan, Xing; Hai, Bo; Sun, Yi-lin; Zhang, Chun-mei; Wang, Song-ling

2009-02-01

To study the ultrastructure of parotid glands, lacrimal glands and pituitary glands between miniature pig and mouse. Five adult miniature pigs and 5 mice were studied. Ultrastructure of their parotid glands, lacrimal glands, and pituitary glands was observed. The secretary granules in acinar cell of miniature pig parotid glands showed higher density and more aequalis than those of mice. The cell apparatus in acinar cell of mouse parotid glands were more plentiful than those of miniature pigs. The secretary granules on blood vessel wall were richer in parotid gland of miniature pigs compared with mouse parotid gland. Lacrimal gland had the similar ultrastructure to parotid gland in these two animals. Many blood vessel antrum were found in pituitary glands of these two animals. Compared with mouse parotid glands, there are more secretary granules in acinar cells and vascular endothelial cells in miniature pig parotid glands, which might enter blood stream and have function of endocrine secretion.

Neonatal systemic inflammation in rats alters retinal vessel development and simulates pathologic features of retinopathy of prematurity.

PubMed

Hong, Hye Kyoung; Lee, Hyun Ju; Ko, Jung Hwa; Park, Ji Hyun; Park, Ji Yeon; Choi, Chang Won; Yoon, Chang-Hwan; Ahn, Seong Joon; Park, Kyu Hyung; Woo, Se Joon; Oh, Joo Youn

2014-05-15

Alteration of retinal angiogenesis during development leads to retinopathy of prematurity (ROP) in preterm infants, which is a leading cause of visual impairment in children. A number of clinical studies have reported higher rates of ROP in infants who had perinatal infections or inflammation, suggesting that exposure of the developing retina to inflammation may disturb retinal vessel development. Thus, we investigated the effects of systemic inflammation on retinal vessel development and retinal inflammation in neonatal rats. To induce systemic inflammation, we intraperitoneally injected 100 μl lipopolysaccharide (LPS, 0.25 mg/ml) or the same volume of normal saline in rat pups on postnatal days 1, 3, and 5. The retinas were extracted on postnatal days 7 and 14, and subjected to assays for retinal vessels, inflammatory cells and molecules, and apoptosis. We found that intraperitoneal injection of LPS impaired retinal vessel development by decreasing vessel extension, reducing capillary density, and inducing localized overgrowth of abnormal retinal vessels and dilated peripheral vascular ridge, all of which are characteristic findings of ROP. Also, a large number of CD11c+ inflammatory cells and astrocytes were localized in the lesion of abnormal vessels. Further analysis revealed that the number of major histocompatibility complex (MHC) class IIloCD68loCD11bloCD11chi cells in the retina was higher in LPS-treated rats compared to controls. Similarly, the levels of TNF-α, IL-1β, and IL-12a were increased in LPS-treated retina. Also, apoptosis was increased in the inner retinal layer where retinal vessels are located. Our data demonstrate that systemic LPS-induced inflammation elicits retinal inflammation and impairs retinal angiogenesis in neonatal rats, implicating perinatal inflammation in the pathogenesis of ROP.

Transcriptome-wide analysis of blood vessels laser captured from human skin and chronic wound-edge tissue

PubMed Central

Roy, Sashwati; Patel, Darshan; Khanna, Savita; Gordillo, Gayle M.; Biswas, Sabyasachi; Friedman, Avner; Sen, Chandan K.

2007-01-01

Chronic wounds represent a substantial public health problem. The development of tools that would enable sophisticated scrutiny of clinical wound tissue material is highly desirable. This work presents evidence enabling rapid specific identification and laser capture of blood vessels from human tissue in a manner which lends itself to successful high-density (U133A) microarray analysis. Such screening of transcriptome followed by real-time PCR and immunohistochemical verification of candidate genes and their corresponding products were performed by using 3 mm biopsies. Of the 18,400 transcripts and variants screened, a focused set of 53 up-regulated and 24 down-regulated genes were noted in wound-derived blood vessels compared with blood vessels from intact human skin. The mean abundance of periostin in wound-site blood vessels was 96-fold higher. Periostin is known to be induced in response to vascular injury and its expression is associated with smooth muscle cell differentiation in vitro and promotes cell migration. Forty-fold higher expression of heparan sulfate 6-O-endosulfatase1 (Sulf1) was noted in wound-site vessels. Sulf1 has been recently recognized to be anti-angiogenic. During embryonic vasculogenesis, CD24 expression is down-regulated in human embryonic stem cells. Wound-site vessels had lower CD24 expression. The findings of this work provide a unique opportunity to appreciate the striking contrast in the transcriptome composition in blood vessels collected from the intact skin and from the wound-edge tissue. Sets of genes with known vascular functions but never connected to wound healing were identified to be differentially expressed in wound-derived blood vessels paving the way for innovative clinically relevant hypotheses. PMID:17728400

Skeletonization algorithm-based blood vessel quantification using in vivo 3D photoacoustic imaging

NASA Astrophysics Data System (ADS)

Meiburger, K. M.; Nam, S. Y.; Chung, E.; Suggs, L. J.; Emelianov, S. Y.; Molinari, F.

2016-11-01

Blood vessels are the only system to provide nutrients and oxygen to every part of the body. Many diseases can have significant effects on blood vessel formation, so that the vascular network can be a cue to assess malicious tumor and ischemic tissues. Various imaging techniques can visualize blood vessel structure, but their applications are often constrained by either expensive costs, contrast agents, ionizing radiations, or a combination of the above. Photoacoustic imaging combines the high-contrast and spectroscopic-based specificity of optical imaging with the high spatial resolution of ultrasound imaging, and image contrast depends on optical absorption. This enables the detection of light absorbing chromophores such as hemoglobin with a greater penetration depth compared to purely optical techniques. We present here a skeletonization algorithm for vessel architectural analysis using non-invasive photoacoustic 3D images acquired without the administration of any exogenous contrast agents. 3D photoacoustic images were acquired on rats (n  =  4) in two different time points: before and after a burn surgery. A skeletonization technique based on the application of a vesselness filter and medial axis extraction is proposed to extract the vessel structure from the image data and six vascular parameters (number of vascular trees (NT), vascular density (VD), number of branches (NB), 2D distance metric (DM), inflection count metric (ICM), and sum of angles metric (SOAM)) were calculated from the skeleton. The parameters were compared (1) in locations with and without the burn wound on the same day and (2) in the same anatomic location before (control) and after the burn surgery. Four out of the six descriptors were statistically different (VD, NB, DM, ICM, p  <  0.05) when comparing two anatomic locations on the same day and when considering the same anatomic location at two separate times (i.e. before and after burn surgery). The study demonstrates an approach to obtain quantitative characterization of the vascular network from 3D photoacoustic images without any exogenous contrast agent which can assess microenvironmental changes related to disease progression.

Spatial Metrics of Tumour Vascular Organisation Predict Radiation Efficacy in a Computational Model

PubMed Central

Scott, Jacob G.

2016-01-01

Intratumoural heterogeneity is known to contribute to poor therapeutic response. Variations in oxygen tension in particular have been correlated with changes in radiation response in vitro and at the clinical scale with overall survival. Heterogeneity at the microscopic scale in tumour blood vessel architecture has been described, and is one source of the underlying variations in oxygen tension. We seek to determine whether histologic scale measures of the erratic distribution of blood vessels within a tumour can be used to predict differing radiation response. Using a two-dimensional hybrid cellular automaton model of tumour growth, we evaluate the effect of vessel distribution on cell survival outcomes of simulated radiation therapy. Using the standard equations for the oxygen enhancement ratio for cell survival probability under differing oxygen tensions, we calculate average radiation effect over a range of different vessel densities and organisations. We go on to quantify the vessel distribution heterogeneity and measure spatial organization using Ripley’s L function, a measure designed to detect deviations from complete spatial randomness. We find that under differing regimes of vessel density the correlation coefficient between the measure of spatial organization and radiation effect changes sign. This provides not only a useful way to understand the differences seen in radiation effect for tissues based on vessel architecture, but also an alternate explanation for the vessel normalization hypothesis. PMID:26800503

Healing Potential of the Anterior Cruciate Ligament Remnant Stump.

PubMed

Trocan, Ilie; Ceausu, Raluca A; Jitariu, Andreea A; Haragus, Horia; Damian, Gratian; Raica, Marius

2016-01-01

The aim of this study was to analyze the microstructural architecture and cellular differentiation of the anterior cruciate ligament (ACL) stumps in different stages after injury, as this could augment graft biointegration. The histological appearance and immunoreaction for cluster of differentiation 34 antigen (CD34) of 54 biopsies from 27 remnants were compared to 10 biopsies from 5 normal cruciate ligaments. CD34 reaction in endothelial cells, fibroblasts and fibrocytes was consistently positive in small synovial vessels. Remnants also exhibited CD34(+) cells among collagen fibers. Blood vessel density varied between specimens. The mean vascular microdensity was 43 per ×200 field in remnants compared to 15.2 in controls. A total of 94.44% of remnant ACL samples had significant hyperplasia of stellate and fusiform stromal cells, CD34(+); 22.4% had developed capillary vessels inside the ligament; 33% exhibited ongoing angiogenesis. Significant differences exist between torn and intact ACL regarding microvascularization. The remnants contain stellate stromal cells and CD34(+) fibrocytes, and display angiogenesis both at synovia as well as in the ligament itself. These findings underline the potential contribution to neoligament healing when remnants are preserved. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

The effect of water contamination on the dew-point temperature scale realization with humidity generators

NASA Astrophysics Data System (ADS)

Vilbaste, M.; Heinonen, M.; Saks, O.; Leito, I.

2013-08-01

The purpose of this paper is to study the effect of contaminated water in the context of humidity generators. Investigation of different methods to determine the drop in dew-point temperature due to contamination and experiments on actual contamination rates are reported. Different methods for calculating the dew-point temperature effect from electrical conductivity and density measurements are studied with high-purity water and aqueous solutions of NaCl and LiCl. The outcomes of the calculation methods are compared with the results of direct humidity measurements. The results show that the often applied Raoult's law based calculation method is in good agreement with other methods. For studying actual contamination, water samples were kept in glass, plastic, copper and stainless-steel vessels for up to 13 months to investigate natural ionic and organic contamination in vessels with different wall materials. The amount of ionic contamination was found to be higher in copper and glass vessels than in stainless-steel and plastic vessels. The amount of organic contamination was found to be highest in the plastic vessel. In all the cases, however, the corresponding drop in dew-point temperature due to natural contamination was found to be below 0.1 mK. The largest rate of change of dew-point temperature was 26 µK/month. Thus, if proper cleanness is maintained in a humidity generator the effect of contamination of water in the saturator is insignificant compared with the major uncertainty components even in the most accurate generators today.

Enhanced neovascularization of dermis substitutes via low-pressure plasma-mediated surface activation.

PubMed

Ring, Andrej; Langer, Stefan; Schaffran, Angela; Stricker, Ingo; Awakowicz, Peter; Steinau, Hans-Ulrich; Hauser, Jörg

2010-12-01

The effect of cold low-pressure plasma treatment on neovascularization of a dermis substitute was evaluated in a mouse model. Collagen-elastin matrices (Matriderm(®)) were used as scaffolds. Low-pressure argon/hydrogene plasma-treated scaffolds were transplanted into the dorsal skinfold chambers of balb/c mice (group 1, n=10). Untreated scaffolds served as controls (group 2, n=10). Intravital fluorescence microscopy was performed within the border zone of the scaffolds on days 1, 5 and 10. Functional vessel density (FVD), vessel diameter, intervascular distance, microvascular permeability, and leukocyte-endothelium interaction were analyzed. An increase of FVD associated with a reduction of the intervascular distance was observed. Statistical analysis revealed that the functional vessel density in the border zone of the scaffolds was significantly enhanced in the plasma-treated group compared to controls. For group 1, an increase of FVD from 282±8 cm/cm(2) on days 5 to 315±8 cm/cm(2) on day 10 was observed. Whereas values of 254±7 cm/cm(2) on day 5 and 275±13 cm/cm(2) on day 10 have resulted in group 2 (mean±S.E.M., Student's t-test, p<0.05). The surface treatment by cold low-pressure plasma intensifies the angiogenesis and accelerates the neovascularization of collagen-elastin matrix. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.

A multiscale modelling approach to understand atherosclerosis formation: A patient-specific case study in the aortic bifurcation

PubMed Central

Alimohammadi, Mona; Pichardo-Almarza, Cesar; Agu, Obiekezie; Díaz-Zuccarini, Vanessa

2017-01-01

Atherogenesis, the formation of plaques in the wall of blood vessels, starts as a result of lipid accumulation (low-density lipoprotein cholesterol) in the vessel wall. Such accumulation is related to the site of endothelial mechanotransduction, the endothelial response to mechanical stimuli and haemodynamics, which determines biochemical processes regulating the vessel wall permeability. This interaction between biomechanical and biochemical phenomena is complex, spanning different biological scales and is patient-specific, requiring tools able to capture such mathematical and biological complexity in a unified framework. Mathematical models offer an elegant and efficient way of doing this, by taking into account multifactorial and multiscale processes and mechanisms, in order to capture the fundamentals of plaque formation in individual patients. In this study, a mathematical model to understand plaque and calcification locations is presented: this model provides a strong interpretability and physical meaning through a multiscale, complex index or metric (the penetration site of low-density lipoprotein cholesterol, expressed as volumetric flux). Computed tomography scans of the aortic bifurcation and iliac arteries are analysed and compared with the results of the multifactorial model. The results indicate that the model shows potential to predict the majority of the plaque locations, also not predicting regions where plaques are absent. The promising results from this case study provide a proof of concept that can be applied to a larger patient population. PMID:28427316

A functional requirement for astroglia in promoting blood vessel development in the early postnatal brain.

PubMed

Ma, Shang; Kwon, Hyo Jun; Huang, Zhen

2012-01-01

Astroglia are a major cell type in the brain and play a key role in many aspects of brain development and function. In the adult brain, astrocytes are known to intimately ensheath blood vessels and actively coordinate local neural activity and blood flow. During development of the neural retina, blood vessel growth follows a meshwork of astrocytic processes. Several genes have also been implicated in retinal astrocytes for regulating vessel development. This suggests a role of astrocytes in promoting angiogenesis throughout the central nervous system. To determine the roles that astrocytes may play during brain angiogenesis, we employ genetic approaches to inhibit astrogliogenesis during perinatal corticogenesis and examine its effects on brain vessel development. We find that conditional deletion from glial progenitors of orc3, a gene required for DNA replication, dramatically reduces glial progenitor cell number in the subventricular zone and astrocytes in the early postnatal cerebral cortex. This, in turn, results in severe reductions in both the density and branching frequency of cortical blood vessels. Consistent with a delayed growth but not regression of vessels, we find neither significant net decreases in vessel density between different stages after normalizing for cortical expansion nor obvious apoptosis of endothelial cells in these mutants. Furthermore, concomitant with loss of astroglial interactions, we find increased endothelial cell proliferation, enlarged vessel luminal size as well as enhanced cytoskeletal gene expression in pericytes, which suggests compensatory changes in vascular cells. Lastly, we find that blood vessel morphology in mutant cortices recovers substantially at later stages, following astrogliosis. These results thus implicate a functional requirement for astroglia in promoting blood vessel growth during brain development.

Mixing device for materials with large density differences

DOEpatents

Gregg, David W.

1994-01-01

An auger-tube pump mixing device for mixing materials with large density differences while maintaining low stirring RPM and low power consumption. The mixing device minimizes the formation of vortexes and minimizes the incorporation of small bubbles in the liquid during mixing. By avoiding the creation of a vortex the device provides efficient stirring of full containers without spillage over the edge. Also, the device solves the problem of effective mixing in vessels where the liquid height is large compared to the diameter. Because of the gentle stirring or mixing by the device, it has application for biomedical uses where cell damage is to be avoided.

Mixing device for materials with large density differences

DOEpatents

Gregg, D.W.

1994-08-16

An auger-tube pump mixing device is disclosed for mixing materials with large density differences while maintaining low stirring RPM and low power consumption. The mixing device minimizes the formation of vortexes and minimizes the incorporation of small bubbles in the liquid during mixing. By avoiding the creation of a vortex the device provides efficient stirring of full containers without spillage over the edge. Also, the device solves the problem of effective mixing in vessels where the liquid height is large compared to the diameter. Because of the gentle stirring or mixing by the device, it has application for biomedical uses where cell damage is to be avoided. 2 figs.

Computer Analysis of Eye Blood-Vessel Images

NASA Technical Reports Server (NTRS)

Wall, R. J.; White, B. S.

1984-01-01

Technique rapidly diagnoses diabetes mellitus. Photographs of "whites" of patients' eyes scanned by computerized image analyzer programmed to quantify density of small blood vessels in conjuctiva. Comparison with data base of known normal and diabetic patients facilitates rapid diagnosis.

Assessing tumor vascularization as a potential biomarker of imatinib resistance in gastrointestinal stromal tumors by dynamic contrast-enhanced magnetic resonance imaging.

PubMed

Consolino, Lorena; Longo, Dario Livio; Sciortino, Marianna; Dastrù, Walter; Cabodi, Sara; Giovenzana, Giovanni Battista; Aime, Silvio

2017-07-01

Most metastatic gastrointestinal stromal tumors (GISTs) develop resistance to the first-line imatinib treatment. Recently, increased vessel density and angiogenic markers were reported in GISTs with a poor prognosis, suggesting that angiogenesis is implicated in GIST tumor progression and resistance. The purpose of this study was to investigate the relationship between tumor vasculature and imatinib resistance in different GIST mouse models using a noninvasive magnetic resonance imaging (MRI) functional approach. Immunodeficient mice (n = 8 for each cell line) were grafted with imatinib-sensitive (GIST882 and GIST-T1) and imatinib-resistant (GIST430) human cell lines. Dynamic contrast-enhanced MRI (DCE-MRI) was performed on GIST xenografts to quantify tumor vessel permeability (K trans ) and vascular volume fraction (v p ). Microvessel density (MVD), permeability (mean dextran density, MDD), and angiogenic markers were evaluated by immunofluorescence and western blot assays. Dynamic contrast-enhanced magnetic resonance imaging showed significantly increased vessel density (P < 0.0001) and permeability (P = 0.0002) in imatinib-resistant tumors compared to imatinib-sensitive ones. Strong positive correlations were observed between MRI estimates, K trans and v p , and their related ex vivo values, MVD (r = 0.78 for K trans and r = 0.82 for v p ) and MDD (r = 0.77 for K trans and r = 0.94 for v p ). In addition, higher expression of vascular endothelial growth factor receptors (VEGFR2 and VEFGR3) was seen in GIST430. Dynamic contrast-enhanced magnetic resonance imaging highlighted marked differences in tumor vasculature and microenvironment properties between imatinib-resistant and imatinib-sensitive GISTs, as also confirmed by ex vivo assays. These results provide new insights into the role that DCE-MRI could play in GIST characterization and response to GIST treatment. Validation studies are needed to confirm these findings.

Reduced heart rate and cardiac output differentially affect angiogenesis, growth, and development in early chicken embryos (Gallus domesticus).

PubMed

Branum, Sylvia R; Yamada-Fisher, Miho; Burggren, Warren

2013-01-01

An increase in both vascular circumferential tension and shear stress in the developing vasculature of the chicken embryo has been hypothesized to stimulate angiogenesis in the developing peripheral circulation chorioallantoic membrane (CAM). To test this hypothesis, angiogenesis in the CAM, development, and growth were measured in the early chicken embryo, following acute and chronic topical application of the purely bradycardic drug ZD7288. At hour 56, ZD7288 reduced heart rate (f(H)) by ~30% but had no significant effect on stroke volume (~0.19 ± 0.2 μL), collectively resulting in a significant fall in cardiac output (CO) from ~27 ± 3 to 18 ± 2 μL min(-1). Mean f(H) at 72 h of development was similarly significantly lowered by acute ZD7288 treatment (250 μM) to 128 ± 0.3 beats min(-1), compared with 174.5 ± 0.3 and 174.7 ± 0.8 beats min(-1) in control and Pannett-Compton (P-C) saline-treated embryos, respectively. Chronic dosing with ZD7288-and the attendant decreases in f(H) and CO-did not change eye diameter or cervical flexion (key indicators of development rate) at 120 h but significantly reduced overall growth (wet and dry body mass decreased by 20%). CAM vessel density index (reflecting angiogenesis) measured 200-400 μm from the umbilical stalk was not altered, but ZD7288 reduced vessel numbers-and therefore vessel density-by 13%-16% more distally (500-600 μm from umbilical stalk) in the CAM. In the ZD7288-treated embryos, a decrease in vessel length was found within the second branch order (~300-400 μm from the umbilical stock), while a decrease in vessel diameter was found closer to the umbilical stock, beginning in the first branch order (~200-300 μm). Paradoxically, chronic application of P-C saline also reduced peripheral CAM vessel density index at 500 and 600 μm by 13% and 7%, respectively, likely from washout of local angiogenic factors. In summary, decreased f(H) with reduced CO did not slow development rate but reduced embryonic growth rate and angiogenesis in the CAM periphery. This study demonstrates for the first time that different processes in the ontogeny of the early vertebrate embryo (i.e., hypertrophic growth vs. development) have differential sensitivities to altered convective blood flow.

Choline and its metabolites are differently associated with cardiometabolic risk factors, history of cardiovascular disease, and MRI-documented cerebrovascular disease in older adults12

PubMed Central

Zhang, Shucha; Bhadelia, Rafeeque A; Johnson, Elizabeth J; Lichtenstein, Alice H; Rogers, Gail T; Rosenberg, Irwin H; Smith, Caren E; Zeisel, Steven H

2017-01-01

Background: There is a potential role of choline in cardiovascular and cerebrovascular disease through its involvement in lipid and one-carbon metabolism. Objective: We evaluated the associations of plasma choline and choline-related compounds with cardiometabolic risk factors, history of cardiovascular disease, and cerebrovascular pathology. Design: A cross-sectional subset of the Nutrition, Aging, and Memory in Elders cohort who had undergone MRI of the brain (n = 296; mean ± SD age: 73 ± 8.1 y) was assessed. Plasma concentrations of free choline, betaine, and phosphatidylcholine were measured with the use of liquid-chromatography–stable-isotope dilution–multiple-reaction monitoring–mass spectrometry. A volumetric analysis of MRI was used to determine the cerebrovascular pathology (white-matter hyperintensities and small- and large-vessel infarcts). Multiple linear and logistic regression models were used to examine relations of plasma measures with cardiometabolic risk factors, history of cardiovascular disease, and radiologic evidence of cerebrovascular pathology. Results: Higher concentrations of plasma choline were associated with an unfavorable cardiometabolic risk-factor profile [lower high-density lipoprotein (HDL) cholesterol, higher total homocysteine, and higher body mass index (BMI)] and greater odds of large-vessel cerebral vascular disease or history of cardiovascular disease but lower odds of small-vessel cerebral vascular disease. Conversely, higher concentrations of plasma betaine were associated with a favorable cardiometabolic risk-factor profile [lower low-density lipoprotein (LDL) cholesterol and triglycerides] and lower odds of diabetes. Higher concentrations of plasma phosphatidylcholine were associated with characteristics of both a favorable cardiometabolic risk-factor profile (higher HDL cholesterol, lower BMI, lower C-reactive protein, lower waist circumference, and lower odds of hypertension and diabetes) and an unfavorable profile (higher LDL cholesterol and triglycerides). Conclusion: Choline and its metabolites have differential associations with cardiometabolic risk factors and subtypes of vascular disease, thereby suggesting differing roles in the pathogenesis of cardiovascular and cerebral large-vessel disease compared with that of small-vessel disease. PMID:28356272

Quantification and Correlation of Angiogenesis with Macrophages by Histomorphometric Method in Central and Peripheral Giant Cell Granuloma: An Immunohistochemical Analysis.

PubMed

Kumar, Varsha Vimal; Krishanappa, Savita Jangal; Prakash, Smitha Gowdra; Channabasaviah, Girish Hemdal; Murgod, Sanjay; Pujari, Ravikumar; Kamat, Mamata Sharad

2016-03-01

Angiogenesis is a fundamental process that affects physiologic reactions and pathological processes such as tumour development and metastasis. It is the process of formation of new microvessel from the preexisting vessels. The purpose of this study was to evaluate angiogenesis, macrophage index and correlate the impact of macrophages on angiogenesis in the central and peripheral giant cell granulomas by evaluating immunohistochemically microvessel density, microvessel perimeter and macrophage index. Immunohistochemical analysis was carried on 20 cases of central and peripheral giant cell granulomas each for CD34 and CD68 proteins expression. Inferential statistical analysis was performed using Independent student t-test to assess the microvessel density, microvessel perimeter and macrophage index on continuous scale between Group I and Group II. Level of significance was determined at 5%. Further bivariate analysis using Pearson correlation test was carried out to see the relationship between microvessel density and macrophage index in each group. Microvessel density, micro vessel perimeter and macrophage index was higher in central giant cell granuloma compared to that of peripheral giant cell granuloma. Correlation between microvessel density and macrophage index among these two lesions was statistically insignificant. Angiogenesis as well as the number of macrophages appeared to increase in Central Giant Cell Granuloma in present study. These findings suggest that macrophages may up regulate the angiogenesis in these giant cell granulomas and angiogenesis do have a role in clinical behaviour. However, we could not establish a positive correlation between microvessel density and macrophage index as the values were statistically insignificant. This insignificance may be presumed due to fewer samples taken for study.

Postangioplasty restenosis followed with magnetic resonance imaging in an atherosclerotic rabbit model.

PubMed

Hänni, Mari; Leppänen, Olli; Smedby, Orjan

2012-01-01

Rationale and Objectives. Testing a quantitative, noninvasive method to assess postangioplasty vessel wall changes in an animal model. Material and Methods. Six New Zealand white rabbits were subjected to atherosclerotic injury, including cholesterol-enriched diet, deendothelialization, and percutaneous transluminal angioplasty (PTA) in the distal part of abdominal aorta (four weeks after deendothelialization). The animals were examined with a 1.5T MRI scanner at three times as follows: baseline (six weeks after diet start and two days after PTA) and four weeks and 10 weeks after-PTA. Inflow angiosequence (M2DI) and proton-density-weighted sequence (PDW) were performed to examine the aorta with axial slices. To identify the inner and outer vessel wall boundaries, a dynamic contour algorithm (Gradient Vector Flow Snakes) was applied to the images, followed by calculation of the vessel wall dimensions. The results were compared with histopathological analysis. Results. The wall thickness in the lesion was significantly higher than in the control region at 4 and 10 weeks, reflecting induction of experimentally created after-angioplasty lesion. At baseline, no significant difference between the two regions was present. Conclusions. It is possible to follow the development of vessel wall changes after-PTA with MRI in this rabbit model.

Intermittent Fasting Pretreatment Prevents Cognitive Impairment in a Rat Model of Chronic Cerebral Hypoperfusion.

PubMed

Hu, Yuan; Yang, Ying; Zhang, Miao; Deng, Min; Zhang, Jun-Jian

2017-07-01

Background: Whether intermittent fasting (IF) pretreatment can prevent vascular cognitive dysfunction remains unknown to our knowledge. Objective: We investigated the effects and underlying mechanisms of IF pretreatment on cognitive dysfunction in a permanent 2-vessel occlusion (2VO) vascular dementia rat model. Methods: Male Wistar rats weighing 200 g were subjected to either IF or ad libitum feeding for 12 wk before 2VO surgery. Rats in the IF protocol underwent alternative-day feed deprivation (FD). Memory of the animals was assessed by using the Morris water maze (MWM) and the novel object recognition (NOR) test 6 wk after the surgery. After behavioral testing, malondialdehyde and glutathione concentrations, superoxide dismutase (SOD) activity, gene expression of antioxidative enzymes, inflammatory protein concentrations, and microglia density were determined in the hippocampus of rats. Results: 2-vessel occlusion operation ad libitum (2VO-AL) rats had significantly longer escape latencies on day 4 of the training phase and spent a lower percentage of time in the target quadrant (25% compared with 38% and 41%) in the MWM, and had lower discrimination ratios (47% compared with 65% and 67%) in the NOR test than 2-vessel operation and alternate-day feed deprivation (2VO-FD) and sham operation ad libitum (Sham-AL) rats, respectively ( P < 0.05). This indicates that IF helps to prevent vascular cognitive deficits. 2VO-AL rats also had higher malondialdehyde (3.54 compared with 2.15 and 1.66 nmol/mg protein) and lower glutathione concentrations (53.25 compared with 66.41 and 91.71 nmol/mg protein), lower SOD activity (100.1 compared with 133.3 and 138.5 U/mg protein), lower gene expression of antioxidative enzymes, higher expression of inflammatory proteins, and higher microglia density in the hippocampus than 2VO-FD and Sham-AL rats, respectively ( P < 0.05). This suggests that IF has antioxidative and anti-inflammatory effects. Conclusions: IF pretreatment provided sustained neuroprotection in a rat model of vascular dementia. These effects were associated with reduced oxidative stress and neuroinflammation. © 2017 American Society for Nutrition.

46 CFR 164.009-17 - Density measurement.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 6 2010-10-01 2010-10-01 false Density measurement. 164.009-17 Section 164.009-17...: SPECIFICATIONS AND APPROVAL MATERIALS Noncombustible Materials for Merchant Vessels § 164.009-17 Density measurement. (a) The measurements described in this section are made to determine the density of a sample. (b...

Digital image processing of vascular angiograms

NASA Technical Reports Server (NTRS)

Selzer, R. H.; Beckenbach, E. S.; Blankenhorn, D. H.; Crawford, D. W.; Brooks, S. H.

1975-01-01

The paper discusses the estimation of the degree of atherosclerosis in the human femoral artery through the use of a digital image processing system for vascular angiograms. The film digitizer uses an electronic image dissector camera to scan the angiogram and convert the recorded optical density information into a numerical format. Another processing step involves locating the vessel edges from the digital image. The computer has been programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge information and others from optical density variations within the lumen shadow. These measurements are combined into an atherosclerosis index, which is found in a post-mortem study to correlate well with both visual and chemical estimates of atherosclerotic disease.

Influence of cerebral blood vessel movements on the position of perivascular synapses.

PubMed

Urrecha, Miguel; Romero, Ignacio; DeFelipe, Javier; Merchán-Pérez, Angel

2017-01-01

Synaptic activity is regulated and limited by blood flow, which is controlled by blood vessel dilation and contraction. Traditionally, the study of neurovascular coupling has mainly focused on energy consumption and oxygen delivery. However, the mechanical changes that blood vessel movements induce in the surrounding tissue have not been considered. We have modeled the mechanical changes that movements of blood vessels cause in neighboring synapses. Our simulations indicate that synaptic densities increase or decrease during vascular dilation and contraction, respectively, near the blood vessel walls. This phenomenon may alter the concentration of neurotransmitters and vasoactive substances in the immediate vicinity of the vessel wall and thus may have an influence on local blood flow.

Corneal vascularization in the Florida manatee (Trichechus manatus latirostris) and three-dimensional reconstruction of vessels.

PubMed

Harper, Jennifer Y; Samuelson, Don A; Reep, Roger L

2005-01-01

The cornea of the Florida manatee is unique and unusual in its anatomy in that blood vessels have been found throughout. In all other animal species, this is considered a pathological condition impeding vision, and is usually caused by injury or trauma. The purpose of this study was to more clearly describe corneal vascularization by examining the architecture through three-dimensional reconstruction in order to find possible patterns in size, distribution, and location of blood vessels relative to gender, age, location, and season. Twenty-six eyes from 22 individuals were prepared for histologic examination and subsequent three-dimensional reconstruction. Every specimen examined had blood vessels in the cornea, comprising an average of 0.3% of total surface density (volume) of the cornea. No differences were found between individuals based on gender, age, and season. Environmental influences were not a significant factor either, which was not originally anticipated. The presence of vessels at the level of the anterior epithelium was surprising and it appeared that the vascularization was directed more anteriorly than was originally thought. The presence of blood vessels in a prenatal eye was also found. In all the eyes examined, no signs of injury or trauma could be observed. The presence of blood vessels appears to minimally impair vision based on their low density, size, and location. The association of vessels with the anterior epithelium and development of vessels within the fetus point to an evolutionary adaptation possibly due to the manatee's unique ability to move between water bodies.

Association Between Vessel Density and Visual Acuity in Patients With Diabetic Retinopathy and Poorly Controlled Type 1 Diabetes.

PubMed

Dupas, Bénédicte; Minvielle, Wilfried; Bonnin, Sophie; Couturier, Aude; Erginay, Ali; Massin, Pascale; Gaudric, Alain; Tadayoni, Ramin

2018-05-10

Capillary dropout is a hallmark of diabetic retinopathy, but its role in visual loss remains unclear. To examine how macular vessel density is correlated with visual acuity (VA) in patients younger than 40 years who have type 1 diabetes without macular edema but who have diabetic retinopathy requiring panretinal photocoagulation. Retrospective cohort study of VA and optical coherence tomography angiography data collected from consecutive patients during a single visit to Lariboisière Hospital, a tertiary referral center in Paris, France. The cohort included 22 eyes of 22 patients with type 1 diabetes without macular edema but with bilateral rapidly progressive diabetic retinopathy that was treated with panretinal photocoagulation between August 15, 2015, and December 30, 2016. Eyes were classified into 2 groups by VA: normal (logMAR, 0; Snellen equivalent, 20/20) and decreased (logMAR, >0; Snellen equivalent, <20/20). The control group included 12 eyes from age-matched healthy participants with normal vision. Visual acuity and mean vessel density in 4 retinal vascular plexuses: the superficial vascular plexus and the deep capillary complex, which comprises the intermediate capillary plexus and the deep capillary plexus. Of the 22 participants, 11 (50%) were men, mean (SD) age was 30 (6) years, and mean (SD) hemoglobin A1c level was 8.9% (1.6%). Of the 22 eyes with diabetic retinopathy, 13 (59%) had normal VA and 9 (41%) had decreased VA (mean [SD]: logMAR, 0.12 [0.04]; Snellen equivalent, 20/25). Mean [SE] vessel density was lower for eyes with diabetic retinopathy and normal VA compared with the control group in the superficial vascular plexus (44.1% [0.9%] vs 49.1% [0.9%]; difference, -5.0% [1.3%]; 95% CI, -7.5% to -2.4%; P < .001), in the deep capillary complex (44.3% [1.2%] vs 50.6% [1.3%]; difference, -6.3% [1.8%]; 95% CI, -9.9% to -2.7%; P = .001), in the intermediate capillary plexus (43.8% [1.2%] vs 49.3% [1.2%]; difference, -5.5% [1.7%]; 95% CI, -9.0% to -2.0%; P = .003), and in the deep capillary plexus (24.5% [1.0%] vs 30.5% [1.0%]; difference, -6.1% [1.4%]; 95% CI, -8.9% to -3.2%; P < .001). Mean vessel density was lower in eyes with diabetic retinopathy and decreased VA compared with eyes with diabetic retinopathy and normal VA; the mean (SE) loss was more pronounced in the deep capillary complex (34.6% [1.5%] vs 44.3% [1.2%]; difference, -9.6% [1.9%]; 95% CI, -13.6% to -5.7%; P < .001), especially in the deep capillary plexus (15.2% [1.2%] vs 24.5% [1.0%]; difference, -9.3% [1.5%]; 95% CI, -12.4% to -6.1%; P < .001), than in the superficial vascular plexus (39.6% [1.1%] vs 44.1% [0.9%]; difference, -4.5% [1.4%]; 95% CI, -7.3% to -1.7%; P = .002). These data suggest that in patients with type 1 diabetes without macular edema but with severe nonproliferative or proliferative diabetic retinopathy, decreased VA may be associated with the degree of capillary loss in the deep capillary complex.

Immature blood vessels in rheumatoid synovium are selectively depleted in response to anti-TNF therapy.

PubMed

Izquierdo, Elena; Cañete, Juan D; Celis, Raquel; Santiago, Begoña; Usategui, Alicia; Sanmartí, Raimon; Del Rey, Manuel J; Pablos, José L

2009-12-02

Angiogenesis is considered an important factor in the pathogenesis of Rheumatoid Arthritis (RA) where it has been proposed as a therapeutic target. In other settings, active angiogenesis is characterized by pathologic, immature vessels that lack periendothelial cells. We searched for the presence of immature vessels in RA synovium and analyzed the dynamics of synovial vasculature along the course of the disease, particularly after therapeutic response to TNF antagonists. Synovial arthroscopic biopsies from RA, osteoarthritis (OA) and normal controls were analyzed by double labeling of endothelium and pericytes/smooth muscle mural cells to identify and quantify mature/immature blood vessels. To analyze clinicopathological correlations, a cross-sectional study on 82 synovial biopsies from RA patients with variable disease duration and severity was performed. A longitudinal analysis was performed in 25 patients with active disease rebiopsied after anti-TNF-alpha therapy. We found that most RA synovial tissues contained a significant fraction of immature blood vessels lacking periendothelial coverage, whereas they were rare in OA, and inexistent in normal synovial tissues. Immature vessels were observed from the earliest phases of the disease but their presence or density was significantly increased in patients with longer disease duration, higher activity and severity, and stronger inflammatory cell infiltration. In patients that responded to anti-TNF-alpha therapy, immature vessels were selectively depleted. The mature vasculature was similarly expanded in early or late disease and unchanged by therapy. RA synovium contains a significant fraction of neoangiogenic, immature blood vessels. Progression of the disease increases the presence and density of immature but not mature vessels and only immature vessels are depleted in response to anti-TNFalpha therapy. The different dynamics of the mature and immature vascular fractions has important implications for the development of anti-angiogenic interventions in RA.

Neutral Solution Low in Glucose Degradation Products Is Associated with Less Peritoneal Fibrosis and Vascular Sclerosis in Patients Receiving Peritoneal Dialysis

PubMed Central

Kawanishi, Kunio; Honda, Kazuho; Tsukada, Misao; Oda, Hideaki; Nitta, Kosaku

2013-01-01

♦ Background: The effects of novel biocompatible peritoneal dialysis (PD) solutions on human peritoneal membrane pathology have yet to be determined. Quantitative evaluation of human peritoneal biopsy specimens may reveal the effects of the new solutions on peritoneal membrane pathology. ♦ Methods: Peritoneal specimens from 24 PD patients being treated with either acidic solution containing high-glucose degradation products [GDPs (n = 12)] or neutral solution with low GDPs (n = 12) were investigated at the end of PD. As controls, pre-PD peritoneal specimens, obtained from 13 patients at PD catheter insertion, were also investigated. The extent of peritoneal fibrosis, vascular sclerosis, and advanced glycation end-product (AGE) accumulation were evaluated by quantitative or semi-quantitative methods. The average densities of CD31-positive vessels and podoplanin-positive lymphatic vessels were also determined. ♦ Results: Peritoneal membrane fibrosis, vascular sclerosis, and AGE accumulation were significantly suppressed in the neutral group compared with the acidic group. The neutral group also showed lower peritoneal equilibration test scores and preserved ultrafiltration volume. The density of blood capillaries, but not of lymphatic capillaries, was significantly increased in the neutral group compared with the acidic and pre-PD groups. ♦ Conclusions: Neutral solutions with low GDPs are associated with less peritoneal membrane fibrosis and vascular sclerosis through suppression of AGE accumulation. However, contrary to expectation, blood capillary density was increased in the neutral group. The altered contents of the new PD solutions modified peritoneal membrane morphology and function in patients undergoing PD. PMID:23123670

Arterial tree tracking from anatomical landmarks in magnetic resonance angiography scans

NASA Astrophysics Data System (ADS)

O'Neil, Alison; Beveridge, Erin; Houston, Graeme; McCormick, Lynne; Poole, Ian

2014-03-01

This paper reports on arterial tree tracking in fourteen Contrast Enhanced MRA volumetric scans, given the positions of a predefined set of vascular landmarks, by using the A* algorithm to find the optimal path for each vessel based on voxel intensity and a learnt vascular probability atlas. The algorithm is intended for use in conjunction with an automatic landmark detection step, to enable fully automatic arterial tree tracking. The scan is filtered to give two further images using the top-hat transform with 4mm and 8mm cubic structuring elements. Vessels are then tracked independently on the scan in which the vessel of interest is best enhanced, as determined from knowledge of typical vessel diameter and surrounding structures. A vascular probability atlas modelling expected vessel location and orientation is constructed by non-rigidly registering the training scans to the test scan using a 3D thin plate spline to match landmark correspondences, and employing kernel density estimation with the ground truth center line points to form a probability density distribution. Threshold estimation by histogram analysis is used to segment background from vessel intensities. The A* algorithm is run using a linear cost function constructed from the threshold and the vascular atlas prior. Tracking results are presented for all major arteries excluding those in the upper limbs. An improvement was observed when tracking was informed by contextual information, with particular benefit for peripheral vessels.

Changes in hydraulic conductivity, mechanical properties, and density reflecting the fall in strain along the lateral roots of two species of tropical trees.

PubMed

Christensen-Dalsgaard, Karen K; Ennos, Anthony R; Fournier, Meriem

2007-01-01

Roots have been described as having larger vessels and so greater hydraulic efficiency than the stem. Differences in the strength and stiffness of the tissue within the root system itself are thought to be an adaptation to the loading conditions experienced by the roots and to be related to differences in density. It is not known how potential mechanical adaptations may affect the hydraulic properties of the roots. The change in strength, stiffness, conductivity, density, sapwood area, and second moment of area distally along the lateral roots of two tropical tree species in which the strain is known to decrease rapidly was studied and the values were compared with those of the trunk. It was found that as the strain fell distally along the roots, so did the strength and stiffness of the tissue, whereas the conductivity increased exponentially. These changes appeared to be related to differences in density. In contrast to the distal-most roots, the tissue of the proximal roots had a lower conductivity and higher strength than that of the trunk. This suggests that mechanical requirements on the structure rather than the water potential gradient from roots to branches are responsible for the general pattern that roots have larger vessels than the stem. In spite of their increased transectional area, the buttressed proximal roots were subjected to higher levels of stress and had a lower total conductivity than the rest of the root system.

Thrombospondin-2 overexpression in the skin of transgenic mice reduces the susceptibility to chemically induced multistep skin carcinogenesis.

PubMed

Kunstfeld, Rainer; Hawighorst, Thomas; Streit, Michael; Hong, Young-Kwon; Nguyen, Lynh; Brown, Lawrence F; Detmar, Michael

2014-05-01

We have previously reported stromal upregulation of the endogenous angiogenesis inhibitor thrombospondin-2 (TSP-2) during multistep carcinogenesis, and we found accelerated and enhanced skin angiogenesis and carcinogenesis in TSP-2 deficient mice. To investigate whether enhanced levels of TSP-2 might protect from skin cancer development. We established transgenic mice with targeted overexpression of TSP-2 in the skin and subjected hemizygous TSP-2 transgenic mice and their wild-type littermates to a chemical skin carcinogenesis regimen. TSP-2 transgenic mice showed a significantly delayed onset of tumor formation compared to wild-type mice, whereas the ratio of malignant conversion to squamous cell carcinomas was comparable in both genotypes. Computer-assisted morphometric analysis of blood vessels revealed pronounced tumor angiogenesis already in the early stages of carcinogenesis in wild type mice. TSP-2 overexpression significantly reduced tumor blood vessel density in transgenic mice but had no overt effect on LYVE-1 positive lymphatic vessels. The percentage of desmin surrounded, mature tumor-associated blood vessels and the degree of epithelial differentiation remained unaffected. The antiangiogenic effect of transgenic TSP-2 was accompanied by a significantly increased number of apoptotic tumor cells in transgenic mice. Our results demonstrate that enhanced levels of TSP-2 in the skin result in reduced susceptibility to chemically-induced skin carcinogenesis and identify TSP-2 as a new target for the prevention of skin cancer. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Quantitative assessment of the rheumatoid synovial microvascular bed by gadolinium-DTPA enhanced magnetic resonance imaging

PubMed Central

Gaffney, K.; Cookson, J.; Blades, S.; Coumbe, A.; Blake, D.

1998-01-01

OBJECTIVE—To examine the relation between rate of synovial membrane enhancement, intra-articular pressure (IAP), and histologically determined synovial vascularity in rheumatoid arthritis, using gadolinium-DTPA enhanced magnetic resonance imaging (MRI).
METHODS—Dynamic gadolinium-DTPA enhanced MRI was performed in 31 patients with knee synovitis (10 patients IAP study, 21 patients vascular morphometry study). Rate of synovial membrane enhancement was quantified by line profile analysis using the image processing package ANALYZE. IAP was measured using an intra-compartmental pressure monitor system. Multiple synovial biopsy specimens were obtained by a blind biopsy technique. Blood vessels were identified immunohistochemically using the endothelial cell marker QBend30 and quantified (blood vessel numerical density and fractional area).
RESULTS—Median blood vessel numerical density and fractional area were 77.5/mm2 (IQR; 69.3-110.7) and 5.6% (IQR; 3.4-8.5) respectively. The rate of synovial membrane enhancement (median 2.74 signal intensity units/s, IQR 2.0-3.8) correlated with both blood vessel numerical density (r = 0.46, p < 0.05) and blood vessel fractional area (r = 0.55, p < 0.02). IAP did not influence the rate of enhancement.
CONCLUSIONS—Gadolinium-DTPA enhanced MRI may prove to be a valuable technique for evaluating drugs that influence angiogenesis.

 Keywords: magnetic resonance imaging; rheumatoid arthritis; synovitis; vascularity PMID:9640130

Alternatively Activated Macrophages Play an Important Role in Vascular Remodeling and Hemorrhaging in Patients with Brain Arteriovenous Malformation.

PubMed

Nakamura, Yukihiko; Sugita, Yasuo; Nakashima, Shinji; Okada, Yousuke; Yoshitomi, Munetake; Kimura, Yoshizou; Miyoshi, Hiroaki; Morioka, Motohiro; Ohshima, Koichi

2016-03-01

Angiogenic and immunoactive lesions in brain arteriovenous malformation (BAVM) contribute to hemorrhagic events and the growth of BAVMs. However, the detailed mechanism is unclear. Our objective is to clarify the relationship between hemorrhagic events of BAVM and alternatively activated macrophages in the perinidal dilated capillary network (PDCN). We examined microsurgical specimens of BVMs (n = 29) and focused on the PDCN area. Ten autopsied brains without intracranial disease were the controls. We performed immunostaining of the inflammatory and endothelial cell markers, macrophage markers (CD163 and CD68), and vascular endothelial growth factor A (VEGF-A). We evaluated each cell's density and the vessel density in the PDCN and analyzed the relationship to hemorrhagic events of BAVM. The PDCN was involved in all the resected arteriovenous malformations, and these vessels showed a high rate of CD105 expression (72.0 ± 10.64%), indicating newly proliferating vessels. Alternatively activated macrophages were found, with a high rate (85.6%) for all macrophages (controls, 56.6%). In the hemorrhagic cases, the cell density was significantly higher than that in the nonhemorrhagic cases and controls (hemorrhagic group, 290 ± 44 cells/mm(2); nonhemorrhagic group, 180 ± 59 cells/mm(2); and control, 19 ± 8 cells/mm(2)). The cell density of alternatively activated macrophages showed a positive correlation with the vessel density of the PDCN. Double immunostaining showed that VEGF-A was secreted by alternatively activated macrophages. Our data suggest that alternatively activated macrophages may have some relationships with angiogenesis of PDCN and hemorrhagic event of BAVM. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Influence of cerebral blood vessel movements on the position of perivascular synapses

PubMed Central

DeFelipe, Javier

2017-01-01

Synaptic activity is regulated and limited by blood flow, which is controlled by blood vessel dilation and contraction. Traditionally, the study of neurovascular coupling has mainly focused on energy consumption and oxygen delivery. However, the mechanical changes that blood vessel movements induce in the surrounding tissue have not been considered. We have modeled the mechanical changes that movements of blood vessels cause in neighboring synapses. Our simulations indicate that synaptic densities increase or decrease during vascular dilation and contraction, respectively, near the blood vessel walls. This phenomenon may alter the concentration of neurotransmitters and vasoactive substances in the immediate vicinity of the vessel wall and thus may have an influence on local blood flow. PMID:28199396

Conjunctival microcirculatory blood flow is altered but not abolished in brain dead patients: a prospective observational study.

PubMed

Tamosuitis, Tomas; Pranskunas, Andrius; Balciuniene, Neringa; Pilvinis, Vidas; Boerma, E Christiaan

2016-07-11

The conjunctival microcirculation has potential as a window to cerebral perfusion due to related blood supply, close anatomical proximity and easy accessibility for microcirculatory imaging technique, such as sidestream dark field (SDF) imaging. Our study aims to evaluate conjunctival and sublingual microcirculation in brain dead patients and to compare it with healthy volunteers in two diametrically opposed conditions: full stop versus normal arterial blood supply to the brain. In a prospective observational study we analyzed conjunctival and sublingual microcirculation using SDF imaging in brain dead patients after reaching systemic hemodynamic targets to optimize perfusion of donor organs, and in healthy volunteers. All brain death diagnoses were confirmed by cerebral angiography. Microcirculatory images were obtained and analyzed using standardized published recommendations. Study registered at ClinicalTrials.gov, number NCT02483273. Eleven brain dead patients and eleven apparently healthy controls were enrolled in the study. Microvascular flow index (MFI) of small vessels was significantly lower in brain dead patients in comparison to healthy controls in ocular conjunctiva (2.7 [2.4-2.9] vs. 3.0 [2.9-3.0], p = 0.01) and in sublingual mucosa (2.8 [2.6-2.9] vs. 3.0 [2.9-3.0], p = 0.02). Total vessel density (TVD) and perfused vessel density (PVD) of small vessels were significantly lower in brain dead patients in comparison to healthy controls in ocular conjunctiva (10.2 [6.6-14.8] vs. 18.0 [18.0-25.4] mm/mm(2), p = 0.001 and 5.0 [3.5-7.3] vs. 10.9 [10.9-13.5] 1/mm, p = 0.001), but not in sublingual mucosa. In comparison to healthy controls brain dead patients had a significant reduction in conjunctival microvascular blood flow and density. However, the presence of conjunctival flow in case general cerebral flow is completely absent makes it impossible to use the conjunctival microcirculation as a substitute for brain flow, and further research should focus on the link between the ocular microcirculation, intracranial pressure and alternative ocular circulation.

Peripapillary vessel density changes in Leber's Hereditary Optic Neuropathy: a new biomarker.

PubMed

Balducci, Nicole; Cascavilla, Maria Lucia; Ciardella, Antonio; La Morgia, Chiara; Triolo, Giacinto; Parisi, Vincenzo; Bandello, Francesco; Sadun, Alfredo A; Carelli, Valerio; Barboni, Piero

2018-05-22

The contribution of the microvascular supply to the pathogenesis of Leber's Hereditary Optic Neuropathy (LHON) is poorly understood. We aimed at measuring the peripapillary capillary vessel density (VD) using optical coherence tomography angiography (OCT-A) at different stages of LHON. Prospective, cross-sectional, multicenter, observational study. Twenty-two LHON patients divided in 4 groups: unaffected mutation carriers (LHON-u); early subacute stage (LHON-e); late subacute stage (LHON-l); chronic stage (LHON-ch). OCT-A scans centered on the optic disc were obtained by spectral domain OCT system. VD, retinal nerve fiber layer (RNFL) and ganglion cell inner plexiform layer (GC-IPL) thickness were compared between groups. Significant VD changes were detected in every sector (p<0.0001). In LHON-e, the VD was reduced in the temporal sector compared with LHON-u and in the temporal and inferotemporal sectors compared with controls. In LHON-l, VD was reduced in whole, temporal, superotemporal and inferotemporal sectors compared with LHON-u and controls. In LHON-ch, the VD was reduced in all sectors compared to the other groups. An asynchronous pattern emerged in the temporal sector with VD changes occurring earlier than RNFL thickness changes and together with GC-IPL thinning. Significant peripapillary miscrovascular changes were detected over the different stages of LHON. Studying the vascular network separately from fibers revealed that microvascular changes in the temporal sector preceded the changes of RNFL and mirrored the GC-IPL changes. Measurements of the peripapillary vascular network may become a useful biomarker to monitor the disease process, evaluate therapeutic efficacy and elucidate pathophysiology. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Triamcinolone Acetonide Selectively Inhibits Angiogenesis in Small Blood Vessels and Decreases Vessel Diameter within the Vascular Tree

NASA Technical Reports Server (NTRS)

McKay, Terri L.; Gredeon, Dan J.; Vickerman, Mary B.; Hylton, alan G.; Ribita, Daniela; Olar, Harry H.; Kaiser, Peter K.; Parsons-Wingerter, Patricia

2007-01-01

The steroid triamcinolone acetonide (TA) is a potent anti-angiogenesis drug used to treat retinal vascular diseases that include diabetic retinopathy, vascular occlusions and choroidal neovascularization. To quantify the effects of TA on branching morphology within the angiogenic microvascular tree of the chorioallantoic membrane (CAM) of quail embryos. Increasing concentrations of TA (0-16 ng/ml) were applied topically on embryonic day 7 (E7) to the chorioallantoic membrane (CAM) of quail embryos cultured in Petri dishes, and incubated for an additional 24 or 48 hours until fixation. Binary (black/white) microscopic images of arterial end points were quantified by VESGEN software (for Generational Analysis of Vessel Branching) to obtain major vascular parameters that include vessel diameter (Dv), fractal dimension (Df), tortuosity (Tv) and densities of vessel area, length, number and branch point (Av, Lv, Nv and Brv). For assessment of specific changes in vascular morphology induced by TA, the VESGEN software automatically segmented the vascular tree into branching generations (G1...G10) according to changes in vessel diameter and branching. Vessel density decreased significantly up to 34% as the function of increasing concentration of TA according to Av, Lv, Brv, Nv and Df. TA selectively inhibited the growth of new, small vessels, because Lv decreased from 13.14plus or minus 0.61 cm/cm2 for controls to 8.012 plus or minus 0.82 cm/cm2 at 16 ng TA/ml in smaller branching generations (G7-G10), and for Nv from 473.83 plus or minus 29.85 cm(-)2 to 302.32 plus or minus 33.09 cm-()2. In contrast, vessel diameter (Dv) decreased throughout the vascular tree (G1-G10).

Monitoring system for a liquid-cooled nuclear fission reactor

DOEpatents

DeVolpi, Alexander

1987-01-01

A monitoring system for detecting changes in the liquid levels in various regions of a water-cooled nuclear power reactor, viz., in the downcomer, in the core, in the inlet and outlet plenums, at the head, and elsewhere; and also for detecting changes in the density of the liquid in these regions. A plurality of gamma radiation detectors are used, arranged vertically along the outside of the reactor vessel, and collimator means for each detector limits the gamma-radiation it receives as emitting from only isolated regions of the vessel. Excess neutrons produced by the fission reaction will be captured by the water coolant, by the steel reactor walls, or by the fuel or control structures in the vessel. Neutron capture by steel generates gamma radiation having an energy level of the order of 5-12 MeV, whereas neutron capture by water provides an energy level of approximately 2.2 MeV, and neutron capture by the fission fuel or its cladding provides an energy level of 1 MeV or less. The intensity of neutron capture thus changes significantly at any water-metal interface. Comparative analysis of adjacent gamma detectors senses changes from the normal condition with liquid coolant present to advise of changes in the presence and/or density of the coolant at these specific regions. The gamma detectors can also sense fission-product gas accumulation at the reactor head to advise of a failure of fuel-pin cladding.

Avicennia germinans (black mangrove) vessel architecture is linked to chilling and salinity tolerance in the Gulf of Mexico

PubMed Central

Madrid, Eric N.; Armitage, Anna R.; López-Portillo, Jorge

2014-01-01

Over the last several decades, the distribution of the black mangrove Avicennia germinans in the Gulf of Mexico has expanded, in part because it can survive the occasional freeze events and high soil salinities characteristic of the area. Vessel architecture may influence mangrove chilling and salinity tolerance. We surveyed populations of A. germinans throughout the Gulf to determine if vessel architecture was linked to field environmental conditions. We measured vessel density, hydraulically weighted vessel diameter, potential conductance capacity, and maximum tensile fracture stress. At each sampling site we recorded mangrove canopy height and soil salinity, and determined average minimum winter temperature from archived weather records. At a subset of sites, we measured carbon fixation rates using a LI-COR 6400XT Portable Photosynthesis System. Populations of A. germinans from cooler areas (Texas and Louisiana) had narrower vessels, likely reducing the risk of freeze-induced embolisms but also decreasing water conductance capacity. Vessels were also narrower in regions with high soil salinity, including Texas, USA and tidal flats in Veracruz, Mexico. Vessel density did not consistently vary with temperature or soil salinity. In abiotically stressful areas, A. germinans had a safe hydraulic architecture with narrower vessels that may increase local survival. This safe architecture appears to come at a substantial physiological cost in terms of reduction in conductance capacity and carbon fixation potential, likely contributing to lower canopy heights. The current distribution of A. germinans in the Gulf is influenced by the complex interplay between temperature, salinity, and vessel architecture. Given the plasticity of A. germinans vessel characters, it is likely that this mangrove species will be able to adapt to a wide range of potential future environmental conditions, and continue its expansion in the Gulf of Mexico in response to near-term climate change. PMID:25309570

Avicennia germinans (black mangrove) vessel architecture is linked to chilling and salinity tolerance in the Gulf of Mexico.

PubMed

Madrid, Eric N; Armitage, Anna R; López-Portillo, Jorge

2014-01-01

Over the last several decades, the distribution of the black mangrove Avicennia germinans in the Gulf of Mexico has expanded, in part because it can survive the occasional freeze events and high soil salinities characteristic of the area. Vessel architecture may influence mangrove chilling and salinity tolerance. We surveyed populations of A. germinans throughout the Gulf to determine if vessel architecture was linked to field environmental conditions. We measured vessel density, hydraulically weighted vessel diameter, potential conductance capacity, and maximum tensile fracture stress. At each sampling site we recorded mangrove canopy height and soil salinity, and determined average minimum winter temperature from archived weather records. At a subset of sites, we measured carbon fixation rates using a LI-COR 6400XT Portable Photosynthesis System. Populations of A. germinans from cooler areas (Texas and Louisiana) had narrower vessels, likely reducing the risk of freeze-induced embolisms but also decreasing water conductance capacity. Vessels were also narrower in regions with high soil salinity, including Texas, USA and tidal flats in Veracruz, Mexico. Vessel density did not consistently vary with temperature or soil salinity. In abiotically stressful areas, A. germinans had a safe hydraulic architecture with narrower vessels that may increase local survival. This safe architecture appears to come at a substantial physiological cost in terms of reduction in conductance capacity and carbon fixation potential, likely contributing to lower canopy heights. The current distribution of A. germinans in the Gulf is influenced by the complex interplay between temperature, salinity, and vessel architecture. Given the plasticity of A. germinans vessel characters, it is likely that this mangrove species will be able to adapt to a wide range of potential future environmental conditions, and continue its expansion in the Gulf of Mexico in response to near-term climate change.

Granulation tissue formation at the bronchial stump is reduced after stapler closure in comparison to suture closure in dogs.

PubMed

Izumi, Yotaro; Kawamura, Masafumi; Gika, Masatoshi; Nomori, Hiroaki

2010-03-01

The aim of this study was to compare the morphology of the bronchial stump after lobectomy between mechanical stapler closure and manual suture closure. The effect of fibrin glue application on each method of closure was also observed. Right upper lobectomy was performed in beagles (n=31) using staplers (ST group) or sutures (SU group). In a separate experiment, fibrin glue was sprayed onto the stump after each respective method of closure. After one week, the stump region was examined macroscopically, and also by histology. chi(2)-Test and Mann-Whitney test were used for comparative analysis. The incidence of adhesion formation between the surrounding tissues was significantly reduced in the ST group in comparison to the SU group (22 vs. 80%, P=0.04). The thickness of granulation tissue over the stump was significantly reduced in the ST group in comparison to the SU group (0.8+/-0.2 vs. 2.5+/-0.3 mm, P<0.0001). Vessel density in the granulation tissue was also significantly reduced in the ST group in comparison to the SU group (6+/-2 vs. 16+/-2, P=0.003). Fibrin glue application after stapler closure significantly increased the incidence of adhesion formation, granulation tissue thickness, and vessel density in the granulation tissue over the stump.

Maritime dynamic traffic generator. Volume 3 : density data on world maps

DOT National Transportation Integrated Search

1975-06-01

The 18,000 vessels whose weekly movements are tracked by the maritime traffic generator represent 106 different countries. There are 4915 vessels five or less years old. The record for the week of January 26, 1972 includes 11,789 arrivals, 10,896 dep...

Titanium subhydride potassium perchlorate (TiH1.65/KClO4) burn rates from hybrid closed bomb-strand burner experiments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, Marcia A.; Oliver, Michael S.

2012-08-01

A hybrid closed bomb-strand burner is used to measure the burning behavior of the titanium subhydride potassium perchlorate pyrotechnic with an equivalent hydrogen concentration of 1.65. This experimental facility allows for simultaneous measurement of the closed bomb pressure rise and pyrotechnic burn rate as detected by electrical break wires over a range of pressures. Strands were formed by pressing the pyrotechnic powders to bulk densities between 60% and 90% theoretical maximum density. The burn rate dependance on initial density and vessel pressure are measured. At all initial strand densities, the burn is observed to transition from conductive to convective burningmore » within the strand. The measured vessel pressure history is further analyzed following the closed bomb analysis methods developed for solid propellants.« less

CT and histopathologic characteristics of lung adenocarcinoma with pure ground-glass nodules 10 mm or less in diameter.

PubMed

Wu, Fang; Tian, Shu-Ping; Jin, Xin; Jing, Rui; Yang, Yue-Qing; Jin, Mei; Zhao, Shao-Hong

2017-10-01

To evaluate CT and histopathologic features of lung adenocarcinoma with pure ground-glass nodule (pGGN) ≤10 mm in diameter. CT appearances of 148 patients (150 lesions) who underwent curative resection of lung adenocarcinoma with pGGN ≤10 mm (25 atypical adenomatous hyperplasias, 42 adenocarcinoma in situs, 38 minimally invasive adenocarcinomas, and 45 invasive pulmonary adenocarcinomas) were analyzed for lesion size, density, bubble-like sign, air bronchogram, vessel changes, margin, and tumour-lung interface. CT characteristics were compared among different histopathologic subtypes. Univariate and multivariate analysis were used to assess the relationship between CT characteristics of pGGN and lesion invasiveness, respectively. There were statistically significant differences among histopathologic subtypes in lesion size, vessel changes, and tumour-lung interface (P<0.05). Univariate analysis revealed significant differences of vessel changes, margin and tumour-lung interface between preinvasive and invasive lesions (P<0.05). Logistic regression analysis showed that the vessel changes, unsmooth margin and clear tumour-lung interface were significant predictive factors for lesion invasiveness, with odds ratios (95% CI) of 2.57 (1.17-5.62), 1.83 (1.25-2.68) and 4.25 (1.78-10.14), respectively. Invasive lesions are found in 55.3% of subcentimeter pGGNs in our cohort. Vessel changes, unsmooth margin, and clear lung-tumour interface may indicate the invasiveness of lung adenocarcinoma with subcentimeter pGGN. • Invasive lesions were found in 55.3% of lung adenocarcinomas with subcentimeter pGGNs • Lesion size, vessel changes, and tumour-lung interface showed different among histopathologic subtypes • Vessel changes, unsmooth margin and clear tumour-lung interface were predictors for lesion invasiveness.

Do xylem fibers affect vessel cavitation resistance?

PubMed

Jacobsen, Anna L; Ewers, Frank W; Pratt, R Brandon; Paddock, William A; Davis, Stephen D

2005-09-01

Possible mechanical and hydraulic costs to increased cavitation resistance were examined among six co-occurring species of chaparral shrubs in southern California. We measured cavitation resistance (xylem pressure at 50% loss of hydraulic conductivity), seasonal low pressure potential (P(min)), xylem conductive efficiency (specific conductivity), mechanical strength of stems (modulus of elasticity and modulus of rupture), and xylem density. At the cellular level, we measured vessel and fiber wall thickness and lumen diameter, transverse fiber wall and total lumen area, and estimated vessel implosion resistance using (t/b)(h)(2), where t is the thickness of adjoining vessel walls and b is the vessel lumen diameter. Increased cavitation resistance was correlated with increased mechanical strength (r(2) = 0.74 and 0.76 for modulus of elasticity and modulus of rupture, respectively), xylem density (r(2) = 0.88), and P(min) (r(2) = 0.96). In contrast, cavitation resistance and P(min) were not correlated with decreased specific conductivity, suggesting no tradeoff between these traits. At the cellular level, increased cavitation resistance was correlated with increased (t/b)(h)(2) (r(2) = 0.95), increased transverse fiber wall area (r(2) = 0.89), and decreased fiber lumen area (r(2) = 0.76). To our knowledge, the correlation between cavitation resistance and fiber wall area has not been shown previously and suggests a mechanical role for fibers in cavitation resistance. Fiber efficacy in prevention of vessel implosion, defined as inward bending or collapse of vessels, is discussed.

Short-term culture of adult bovine ovarian tissues: chorioallantoic membrane (CAM) vs. traditional in vitro culture systems.

PubMed

Beck, Kylie; Singh, Jaswant; Dar, Mohammad Arshud; Anzar, Muhammad

2018-03-09

A suitable culture system is important for follicle growth in adult bovine ovarian tissue. This study aimed to assess the avian chorioallantoic membrane (CAM) for short-term culture of adult bovine ovarian tissues compared with a traditional in vitro culture system. Ovarian cortical tissues (1-2 mm 3 ), collected from slaughtered adult cows, were randomly assigned to control, CAM or in vitro culture groups. In the control group, ovarian tissues were fixed with paraformaldehyde without culture. In CAM and in vitro culture groups, the ovarian tissues were cultured for up to 5 days and then fixed. Ovarian tissues were examined on culture days 0, 1, 3 and 5 for angiogenesis, follicle morphology and growth. In all groups, primordial and growing (healthy and atretic) follicle densities were determined. In the CAM culture, the avian blood vessel density increased (p < 0.01) over time with a decline (p < 0.001) in the bovine blood vessel density. Healthy primordial, atretic primordial and healthy growing follicle densities were higher (p < 0.05) in CAM-cultured ovarian tissues than in vitro-cultured tissues. Regardless of the culture system, the density of healthy primordial follicles decreased (p < 0.001) over time with an increase in healthy growing follicles on day 3 (p < 0.01) and an increase in atretic (primordial and growing) follicles during the 5-day culture period (p < 0.001). The proportions of healthy primordial and atretic growing follicles were also affected by culture day (p < 0.001). The CAM culture in chick embryos supported the bovine ovarian tissue grafts for 3 days demonstrating that CAM can be used as a satisfactory short-term culture system to assess ovarian tissue health, and to study follicle activation and development.

Quantifying retinal microvascular changes in uveitis using spectral domain optical coherence tomography angiography (SD-OCTA)

PubMed Central

Kim, Alice Y.; Rodger, Damien C.; Shahidzadeh, Anoush; Chu, Zhongdi; Koulisis, Nicole; Burkemper, Bruce; Jiang, Xuejuan; Pepple, Kathryn L.; Wang, Ruikang K.; Puliafito, Carmen A.; Rao, Narsing A.; Kashani, Amir H.

2016-01-01

Purpose To quantify retinal capillary density and morphology in uveitis using SD-OCTA. Design Cross-sectional, observational study Methods Healthy and uveitic subjects were recruited from two tertiary care eye centers. Prototype SD-OCTA devices (Cirrus, Carl Zeiss Meditec, Inc., Dublin, CA) were used to generate 3×3 mm2 OCTA images centered on the fovea. Subjects were placed into 3 groups based on the type of optical microangiography (OMAG) algorithm used for image processing (intensity-and/or phase) and type of retinal segmentation (automatic or manual). A semi-automated method was used to calculate skeleton density (SD), vessel density (VD), fractal dimension (FD), and vessel diameter index (VDI). Retinal vasculature was assessed in the superficial retinal layer (SRL), deep retinal layer (DRL), and non-segmented retinal layer (NS-RL). A generalized estimating equations model was used to analyze associations between the OCTA measures and disease status within each retinal layer. A P value < 0.05 was accepted as significant. Reproducibility and repeatability were assessed using the Intraclass Correlation Coefficient (ICC). Results The SD, VD, and FD of the parafoveal capillaries were lower in uveitic eyes compared to healthy eyes in all retinal segments. In addition, SD and VD were significantly lower in the DRL of subjects with uveitic macular edema. There was no correlation in any capillary parameters and anatomic classification of uveitis. Conclusions Quantitative analysis of parafoveal capillary density and morphology in uveitis demonstrates significantly lower capillary density and complexity. SD-OCTA algorithms are robust enough to detect these changes and can provide a novel diagnostic index of disease for uveitis subjects. PMID:27594138

Flow Correlated Percolation during Vascular Remodeling in Growing Tumors

NASA Astrophysics Data System (ADS)

Lee, D.-S.; Rieger, H.; Bartha, K.

2006-02-01

A theoretical model based on the molecular interactions between a growing tumor and a dynamically evolving blood vessel network describes the transformation of the regular vasculature in normal tissues into a highly inhomogeneous tumor specific capillary network. The emerging morphology, characterized by the compartmentalization of the tumor into several regions differing in vessel density, diameter, and necrosis, is in accordance with experimental data for human melanoma. Vessel collapse due to a combination of severely reduced blood flow and solid stress exerted by the tumor leads to a correlated percolation process that is driven towards criticality by the mechanism of hydrodynamic vessel stabilization.

Blood-nerve barrier: distribution of anionic sites on the endothelial plasma membrane and basal lamina of dorsal root ganglia.

PubMed

Bush, M S; Reid, A R; Allt, G

1991-09-01

Previous investigations of the blood-nerve barrier have correlated the greater permeability of ganglionic endoneurial vessels, compared to those of nerve trunks, with the presence of fenestrations and open intercellular junctions. Recent studies have demonstrated reduced endothelial cell surface charge in blood vessels showing greater permeability. To determine the distribution of anionic sites on the plasma membranes and basal laminae of endothelial cells in dorsal root ganglia, cationic colloidal gold and cationic ferritin were used. Electron microscopy revealed the existence of endothelial microdomains with differing labelling densities. Labelling indicated that caveolar and fenestral diaphragms and basal laminae are highly anionic at physiological pH, luminal plasma membranes and endothelial processes are moderately charged and abluminal plasma membranes are weakly anionic. Tracers did not occur in caveolae or cytoplasmic vesicles. In vitro tracer experiments at pH values of 7.3, 5.0, 3.5 and 2.0 indicated that the anionic charge on the various endothelial domains was contributed by chemical groups with differing pKa values. In summary, the labelling of ganglionic and sciatic nerve vessels was similar except for the heavy labelling of diaphragms in a minority of endoneurial vessels in ganglia. This difference is likely to account in part for the greater permeability of ganglionic endoneurial vessels. The results are discussed with regard to the blood-nerve and -brain barriers and vascular permeability in other tissues and a comparison made between the ultrastructure and anionic microdomains of epi-, peri- and endoneurial vessels of dorsal root ganglia and sciatic nerves.

Priming with a combination of proangiogenic growth factors improves wound healing in normoglycemic mice

PubMed Central

Ackermann, Maximilian; Wolloscheck, Tanja; Wellmann, Axel; Li, Vincent W.; Li, William W.; Konerding, Moritz A.

2012-01-01

Growth factors and/or angiogenic factors are supposed to improve wound healing. The aim of our study was to evaluate the effects of subcutaneous pretreatment with combinatory proangiogenic factors on wound closure, mechanical properties, vessel density, and morphology. Twenty-eight Balb/c mice were divided equally into two groups. A mixture of VEGF (35.0 μg), bFGF (2.5 μg), and PDGF (3.5 μg) was administered 3, 5, and 7 days subcutaneously to 14 mice before full thickness skin punch biopsy wounding, whereas 14 control animals received three times 0.2 ml saline solution. Wound sizes were assessed daily and the repaired tissues were harvested 7 days after complete wound closure. Complete closure (≥95% healing of initial wound area) was reached in all proangiogenic pretreated animals on day 10, whereas controls needed 13 days for complete closure. Tensile strengths were nearly twofold higher than in the controls (p≤0.01). The punch biopsy material revealed 4.2 fold higher vessel densities in the proangiogenic pretreated group. On day 17, the vessel densities in the proangiogenic pretreated wounds were also 3.2 fold higher than in the untreated controls. No significant differences were seen in the collagen ratio. Pretreatment with proangiogenic factors revealed several significant effects on wound healing: faster time to closure, a higher vessel density, better functional outcome. These results suggest a beneficial effect of pretreatment with combinatory growth factors in mouse skin wounds without impaired wound healing. This might be exploited in further investigations in diabetic healing as a therapeutic approach for elective surgery. PMID:21373751

Superficial ovarian cortex vascularization is inversely related to the follicle reserve in normal cycling ovaries and is increased in polycystic ovary syndrome.

PubMed

Delgado-Rosas, F; Gaytán, M; Morales, C; Gómez, R; Gaytán, F

2009-05-01

The superficial ovarian cortex constitutes the micro-environment where resting and early growing follicles reside. As small follicles do not possess an independent capillary network, both their survival and early growth depend on their proximity to the cortical vessels. Little is known about the possible changes in superficial ovarian cortex vascularization in normal women throughout reproductive life or in pathological conditions such as polycystic ovary syndrome (PCOS) involving abnormal early follicle growth. We studied the vascularization of the superficial and deep cortical stroma (DCS) in normal cycling ovaries from 21 to 50 years of age and in infertile women with PCOS. We used archival ovarian samples and specific CD34 immunostaining to determine blood vessel density and to analyse correlation with age and with the ovarian follicle reserve. Normal cycling ovaries showed an age-related increase in the superficial cortical stroma vascularization that was inversely correlated with the density of small (primordial and primary) follicles. In contrast, blood vessel density in the DCS significantly decreased in women aged >or=40 years. Ovaries from PCOS showed a 2-fold increase in blood vessel density in both superficial cortical stroma and DCS with respect to age-matched controls. The increased vascularization of the superficial cortical stroma in normal ovaries in relation to age and in ovaries from PCOS could have profound effects on cortical metabolic rate, primordial follicle survival/activation and early follicle growth, and may underline changes in follicle dynamics in mid-aged women and in PCOS.

Postangioplasty Restenosis Followed with Magnetic Resonance Imaging in an Atherosclerotic Rabbit Model

PubMed Central

Hänni, Mari; Leppänen, Olli; Smedby, Örjan

2012-01-01

Rationale and Objectives. Testing a quantitative, noninvasive method to assess postangioplasty vessel wall changes in an animal model. Material and Methods. Six New Zealand white rabbits were subjected to atherosclerotic injury, including cholesterol-enriched diet, deendothelialization, and percutaneous transluminal angioplasty (PTA) in the distal part of abdominal aorta (four weeks after deendothelialization). The animals were examined with a 1.5T MRI scanner at three times as follows: baseline (six weeks after diet start and two days after PTA) and four weeks and 10 weeks after-PTA. Inflow angiosequence (M2DI) and proton-density-weighted sequence (PDW) were performed to examine the aorta with axial slices. To identify the inner and outer vessel wall boundaries, a dynamic contour algorithm (Gradient Vector Flow Snakes) was applied to the images, followed by calculation of the vessel wall dimensions. The results were compared with histopathological analysis. Results. The wall thickness in the lesion was significantly higher than in the control region at 4 and 10 weeks, reflecting induction of experimentally created after-angioplasty lesion. At baseline, no significant difference between the two regions was present. Conclusions. It is possible to follow the development of vessel wall changes after-PTA with MRI in this rabbit model. PMID:23316216

Digital image processing of vascular angiograms

NASA Technical Reports Server (NTRS)

Selzer, R. H.; Blankenhorn, D. H.; Beckenbach, E. S.; Crawford, D. W.; Brooks, S. H.

1975-01-01

A computer image processing technique was developed to estimate the degree of atherosclerosis in the human femoral artery. With an angiographic film of the vessel as input, the computer was programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge information and others from optical density variations within the lumen shadow. These measurements were combined into an atherosclerosis index, which was found to correlate well with both visual and chemical estimates of atherosclerotic disease.

Measurement of the perfusion fraction in brain tumors with intravoxel incoherent motion MR imaging: validation with histopathological vascular density in meningiomas.

PubMed

Togao, Osamu; Hiwatashi, Akio; Yamashita, Koji; Kikuchi, Kazufumi; Momosaka, Daichi; Yoshimoto, Koji; Kuga, Daisuke; Mizoguchi, Masahiro; Suzuki, Satoshi O; Iwaki, Toru; Van Cauteren, Marc; Iihara, Koji; Honda, Hiroshi

2018-05-01

To evaluate the quantification performance of the perfusion fraction (f) measured with intravoxel incoherent motion (IVIM) MR imaging in a comparison with the histological vascular density in meningiomas. 29 consecutive patients with meningioma (59.0 ± 16.8 years old, 8 males and 21 females) who underwent a subsequent surgical resection were examined with both IVIM imaging and a histopathological analysis. IVIM imaging was conducted using a single-shot SE-EPI sequence with 13 b-factors (0, 10, 20, 30, 50, 80, 100, 200, 300, 400, 600, 800, 1000 s mm - 2 ) at 3T. The perfusion fraction (f) was calculated by fitting the IVIM bi-exponential model. The 90-percentile f-value in the tumor region-of-interest (ROI) was defined as the maximum f-value (f-max). Histopathological vascular density (%Vessel) was measured on CD31-immunostainted histopathological specimens. The correlation and agreement between the f-values and %Vessel was assessed. The f-max (15.5 ± 5.5%) showed excellent agreement [intraclass correlation coefficient (ICC) = 0.754] and a significant correlation (r = 0.69, p < 0.0001) with the %Vessel (12.9 ± 9.4%) of the tumors. The Bland-Altman plot analysis showed excellent agreement between the f-max and %Vessel (bias, -2.6%; 95% limits of agreement, from -16.0 to 10.8%). The f-max was not significantly different among the histological subtypes of meningioma. An excellent agreement and a significant correlation were observed between the f-values and %Vessel. The f-value can be used as a noninvasive quantitative imaging measure to directly assess the vascular volume fraction in brain tumors. Advances in knowledge: The f-value measured by IVIM imaging showed a significant correlation and an excellent agreement with the histological vascular density in the meningiomas. The f-value can be used as a noninvasive and quantitative imaging measure to directly assess the volume fraction of capillaries in brain tumors.

Repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography macular metrics in healthy subjects.

PubMed

Fang, Danqi; Tang, Fang Yao; Huang, Haifan; Cheung, Carol Y; Chen, Haoyu

2018-05-29

To investigate the repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography (SS-OCTA) metrics in healthy subjects. Thirty-three healthy normal subjects were enrolled. The macula was scanned four times by an SS-OCTA system using the 3 mm×3 mm mode. The superficial capillary map images were analysed using a MATLAB program. A series of parameters were measured: foveal avascular zone (FAZ) area, FAZ perimeter, FAZ circularity, parafoveal vessel density, fractal dimension and vessel diameter index (VDI). The repeatability of four scans was determined by intraclass correlation coefficient (ICC). Then the averaged results were analysed for intereye difference, correlation and agreement using paired t-test, Pearson's correlation coefficient (r), ICC and Bland-Altman plot. The repeatability assessment of the macular metrics exported high ICC values (ranged from 0.853 to 0.996). There is no statistically significant difference in the OCTA metrics between the two eyes. FAZ area (ICC=0.961, r=0.929) and FAZ perimeter (ICC=0.884, r=0.802) showed excellent binocular correlation. Fractal dimension (ICC=0.732, r=0.578) and VDI (ICC=0.707, r=0.547) showed moderate binocular correlation, while parafoveal vessel density had poor binocular correlation. Bland-Altman plots showed the range of agreement was from -0.0763 to 0.0954 mm 2 for FAZ area and from -0.0491 to 0.1136 for parafoveal vessel density. The macular metrics obtained using SS-OCTA showed excellent repeatability in healthy subjects. We showed high intereye correlation in FAZ area and perimeter, moderate correlation in fractal dimension and VDI, while vessel density had poor correlation in normal healthy subjects. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Thromboxane receptor density is increased in human cardiovascular disease with evidence for inhibition at therapeutic concentrations by the AT1 receptor antagonist losartan

PubMed Central

Katugampola, Sidath D; Davenport, Anthony P

2001-01-01

The aim of this study was to establish how thromboxane receptors (TP) respond to the increase in levels of plasma thromboxane observed in both cardiac (cardiomyopathy, ischaemic heart disease and pulmonary hypertension) and vascular disease (atherosclerosis of coronary artery disease and accelerated atherosclerosis of saphenous vein grafts).The agonist radioligand [125I]-BOP, bound rapidly to TP receptors in normal human cardiovascular tissue, displaying high affinity in left ventricle (KD 0.23±0.06 nM, Bmax 28.4±5.7 fmol mg−1 protein) and reversibility with a t1/2 of 10 min (n=five individuals±s.e.mean).In the heart, TP receptor density in the right ventricle of primary pulmonary hypertensive patients were significantly increased (66.6±6 fmol mg−1 protein) compared to non-diseased right ventricle (37.9±4.1 fmol mg−1 protein, n=six individuals±s.e.mean, P<0.05).In diseased vessels, TP receptor densities were significantly increased (3 fold in the intimal layer) in atherosclerotic coronary arteries, saphenous vein grafts with severe intimal thickening (n=8 – 12 individuals, P<0.05) and aortic tissue (n=5 – 6 individuals, P<0.05), compared with normal vessels.Losartan, tested at therapeutic doses, competed for [125I]-BOP binding to human vascular tissue, suggesting that some of the anti-hypertensive effects of this AT1 receptor antagonist could also be mediated by blocking human TP receptors.The differential distribution of TP receptors in the human cardiovascular system and the alteration of receptor density, accompanying the increase in endogenous thromboxane levels in cardiovascular disease, suggest that TP receptors represent a significant target for therapeutic interventions and highlights the importance for the development of novel selective antagonist for use in humans. PMID:11724743

Nickel-hydrogen bipolar battery system

NASA Technical Reports Server (NTRS)

Thaller, L. H.

1982-01-01

Rechargeable nickel-hydrogen systems are described that more closely resemble a fuel cell system than a traditional nickel-cadmium battery pack. This was stimulated by the currently emerging requirements related to large manned and unmanned low Earth orbit applications. The resultant nickel-hydrogen battery system should have a number of features that would lead to improved reliability, reduced costs as well as superior energy density and cycle lives as compared to battery systems constructed from the current state-of-the-art nickel-hydrogen individual pressure vessel cells.

Comparative study of regenerative effects of mesenchymal stem cells derived from placental amnion, chorion and umbilical cord on dermal wounds.

PubMed

Ertl, Juliane; Pichlsberger, Melanie; Tuca, Alexandru-Cristian; Wurzer, Paul; Fuchs, Jakob; Geyer, Stefan H; Maurer-Gesek, Barbara; Weninger, Wolfgang J; Pfeiffer, Dagmar; Bubalo, Vladimir; Parvizi, Daryousch; Kamolz, Lars-Peter; Lang, Ingrid

2018-05-01

Mesenchymal stem/stromal cells derived from human term placentas (PMSCs) are novel therapeutic agents and more topical than ever. Here we evaluated the effects of three types of PMSCs on wound healing in an in vivo mouse model: Amnion-derived MSCs (AMSCs), blood vessel-derived MSCs (BV-MSCs) from the chorionic plate and Wharton's jelly-derived MSCs (WJ-MSCs) from the umbilical cord. We topically applied PMSCs onto skin wounds in mice using the dermal substitute Matriderm ® as carrier and evaluated wound healing parameters. In addition, we investigated the effects of all PMSC types under co-application with placental endothelial cells (PLECs). After 8 days, we compared the percent of wound closure and the angiogenic potential between all groups. AMSCs, BV-MSCs and WJ-MSCs significantly induced a faster healing and a higher number of blood vessels in the wound when compared to controls (Matriderm ® -alone). PLECs did not further improve the advantageous effects of PMSC-treatment. Quantitative data and 3D analysis by high resolution episcopic microscopy confirmed a lower density of vessels in Matriderm ® /PMSCs/PLECs co-application compared to Matriderm ® /PMSCs treatment. Results indicate that all three PMSC types exert similar beneficial effects on wound closure and neovascularization in our mouse model. Using Matriderm ® as carrier for PMSCs propagates rapid cell migration towards the wound area that allows a fast and clinically practicable method for stem cell application. These promising effects warrant further investigation in clinical trials. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

A vessel noise budget for Admiralty Inlet, Puget Sound, Washington (USA).

PubMed

Bassett, Christopher; Polagye, Brian; Holt, Marla; Thomson, Jim

2012-12-01

One calendar year of Automatic Identification System (AIS) ship-traffic data was paired with hydrophone recordings to assess ambient noise in northern Admiralty Inlet, Puget Sound, WA (USA) and to quantify the contribution of vessel traffic. The study region included inland waters of the Salish Sea within a 20 km radius of the hydrophone deployment site. Spectra and hourly, daily, and monthly ambient noise statistics for unweighted broadband (0.02-30 kHz) and marine mammal, or M-weighted, sound pressure levels showed variability driven largely by vessel traffic. Over the calendar year, 1363 unique AIS transmitting vessels were recorded, with at least one AIS transmitting vessel present in the study area 90% of the time. A vessel noise budget was calculated for all vessels equipped with AIS transponders. Cargo ships were the largest contributor to the vessel noise budget, followed by tugs and passenger vessels. A simple model to predict received levels at the site based on an incoherent summation of noise from different vessels resulted in a cumulative probability density function of broadband sound pressure levels that shows good agreement with 85% of the temporal data.

An automated method measures variability in P-glycoprotein and ABCG2 densities across brain regions and brain matter.

PubMed

Kannan, Pavitra; Schain, Martin; Kretzschmar, Warren W; Weidner, Lora; Mitsios, Nicholas; Gulyás, Balázs; Blom, Hans; Gottesman, Michael M; Innis, Robert B; Hall, Matthew D; Mulder, Jan

2017-06-01

Changes in P-glycoprotein and ABCG2 densities may play a role in amyloid-beta accumulation in Alzheimer's disease. However, previous studies report conflicting results from different brain regions, without correcting for changes in vessel density. We developed an automated method to measure transporter density exclusively within the vascular space, thereby correcting for vessel density. We then examined variability in transporter density across brain regions, matter, and disease using two cohorts of post-mortem brains from Alzheimer's disease patients and age-matched controls. Changes in transporter density were also investigated in capillaries near plaques and on the mRNA level. P-glycoprotein density varied with brain region and matter, whereas ABCG2 density varied with brain matter. In temporal cortex, P-glycoprotein density was 53% lower in Alzheimer's disease samples than in controls, and was reduced by 35% in capillaries near plaque deposits within Alzheimer's disease samples. ABCG2 density was unaffected in Alzheimer's disease. No differences were detected at the transcript level. Our study indicates that region-specific changes in transporter densities can occur globally and locally near amyloid-beta deposits in Alzheimer's disease, providing an explanation for conflicting results in the literature. When differences in region and matter are accounted for, changes in density can be reproducibly measured using our automated method.

Axial length variation impacts on retinal vessel density and foveal avascular zone area measurement using optical coherence tomography angiography

NASA Astrophysics Data System (ADS)

Sampson, Danuta M.; Gong, Peijun; An, Di; Menghini, Moreno; Hansen, Alex; Mackey, David A.; Sampson, David D.; Chen, Fred K.

2017-04-01

We examined the impact of axial length on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurement using optical coherence tomography angiography. The SRVD and FAZA were quantified before and after correction for magnification error associated with axial length variation. Although SRVD did not differ before and after correction for magnification error in the parafoveal region, change in foveal SRVD and FAZA were significant. This has implications for clinical trials outcome in diseased eyes where significant capillary dropout may occur in the parafovea.

The effect of irreversible electroporation on blood vessels.

PubMed

Maor, Elad; Ivorra, Antoni; Leor, Jonathan; Rubinsky, Boris

2007-08-01

We present a pilot study on the long term effects of irreversible electroporation (IRE) on a large blood vessel. The study was motivated by the anticipated use of IRE for treatment of cancer tumors abutting large blood vessels. A sequence of 10 direct current IRE pulses of 3800 V/cm, 100 micros each, at a frequency of 10 pulses per second, were applied directly to the carotid artery in six rats. Measuring tissue conductivity during the procedure showed, as predicted, an increase in conductivity during the application of the pulse, which suggests that this measurement can be used to control the application of IRE. All the animals survived the procedure and showed no side effects. Histology performed 28 days after the procedure showed that the connective matrix of the blood vessels remained intact and the number of vascular smooth muscle cells (VSMC) in the arterial wall decreased with no evidence of aneurysm, thrombus formation or necrosis. Average VSMC density was significantly lower following IRE ablation compared with control (24 +/- 11 vs. 139 +/- 14, P<0.001), with no apparent damage to extra cellular matrix components and structure. In addition to the relevance of this study to treatment of cancer near large blood vessels these findings tentatively suggest that IRE has possible applications to treatment of pathological processes in which it is desired to reduce the proliferation of VSMC population, such as restenosis and for attenuating atherosclerotic processes in clinical important locations such as coronary, carotid and renal arteries.

TMA Vessel Segmentation Based on Color and Morphological Features: Application to Angiogenesis Research

PubMed Central

Fernández-Carrobles, M. Milagro; Tadeo, Irene; Bueno, Gloria; Noguera, Rosa; Déniz, Oscar; Salido, Jesús; García-Rojo, Marcial

2013-01-01

Given that angiogenesis and lymphangiogenesis are strongly related to prognosis in neoplastic and other pathologies and that many methods exist that provide different results, we aim to construct a morphometric tool allowing us to measure different aspects of the shape and size of vascular vessels in a complete and accurate way. The developed tool presented is based on vessel closing which is an essential property to properly characterize the size and the shape of vascular and lymphatic vessels. The method is fast and accurate improving existing tools for angiogenesis analysis. The tool also improves the accuracy of vascular density measurements, since the set of endothelial cells forming a vessel is considered as a single object. PMID:24489494

Choline and its metabolites are differently associated with cardiometabolic risk factors, history of cardiovascular disease, and MRI-documented cerebrovascular disease in older adults.

PubMed

Roe, Annie J; Zhang, Shucha; Bhadelia, Rafeeque A; Johnson, Elizabeth J; Lichtenstein, Alice H; Rogers, Gail T; Rosenberg, Irwin H; Smith, Caren E; Zeisel, Steven H; Scott, Tammy M

2017-06-01

Background: There is a potential role of choline in cardiovascular and cerebrovascular disease through its involvement in lipid and one-carbon metabolism. Objective: We evaluated the associations of plasma choline and choline-related compounds with cardiometabolic risk factors, history of cardiovascular disease, and cerebrovascular pathology. Design: A cross-sectional subset of the Nutrition, Aging, and Memory in Elders cohort who had undergone MRI of the brain ( n = 296; mean ± SD age: 73 ± 8.1 y) was assessed. Plasma concentrations of free choline, betaine, and phosphatidylcholine were measured with the use of liquid-chromatography-stable-isotope dilution-multiple-reaction monitoring-mass spectrometry. A volumetric analysis of MRI was used to determine the cerebrovascular pathology (white-matter hyperintensities and small- and large-vessel infarcts). Multiple linear and logistic regression models were used to examine relations of plasma measures with cardiometabolic risk factors, history of cardiovascular disease, and radiologic evidence of cerebrovascular pathology. Results: Higher concentrations of plasma choline were associated with an unfavorable cardiometabolic risk-factor profile [lower high-density lipoprotein (HDL) cholesterol, higher total homocysteine, and higher body mass index (BMI)] and greater odds of large-vessel cerebral vascular disease or history of cardiovascular disease but lower odds of small-vessel cerebral vascular disease. Conversely, higher concentrations of plasma betaine were associated with a favorable cardiometabolic risk-factor profile [lower low-density lipoprotein (LDL) cholesterol and triglycerides] and lower odds of diabetes. Higher concentrations of plasma phosphatidylcholine were associated with characteristics of both a favorable cardiometabolic risk-factor profile (higher HDL cholesterol, lower BMI, lower C-reactive protein, lower waist circumference, and lower odds of hypertension and diabetes) and an unfavorable profile (higher LDL cholesterol and triglycerides). Conclusion: Choline and its metabolites have differential associations with cardiometabolic risk factors and subtypes of vascular disease, thereby suggesting differing roles in the pathogenesis of cardiovascular and cerebral large-vessel disease compared with that of small-vessel disease. © 2017 American Society for Nutrition.

WE-E-17A-01: Characterization of An Imaging-Based Model of Tumor Angiogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adhikarla, V; Jeraj, R

2014-06-15

Purpose: Understanding the transient dynamics of tumor oxygenation is important when evaluating tumor-vasculature response to anti-angiogenic therapies. An imaging-based tumor-vasculature model was used to elucidate factors that affect these dynamics. Methods: Tumor growth depends on its doubling time (Td). Hypoxia increases pro-angiogenic factor (VEGF) concentration which is modeled to reduce vessel perfusion, attributing to its effect of increasing vascular permeability. Perfused vessel recruitment depends on the existing perfused vasculature, VEGF concentration and maximum VEGF concentration (VEGFmax) for vessel dysfunction. A convolution-based algorithm couples the tumor to the normal tissue vessel density (VD-nt). The parameters are benchmarked to published pre-clinical datamore » and a sensitivity study evaluating the changes in the peak and time to peak tumor oxygenation characterizes them. The model is used to simulate changes in hypoxia and proliferation PET imaging data obtained using [Cu- 61]Cu-ATSM and [F-18]FLT respectively. Results: Td and VD-nt were found to be the most influential on peak tumor pO2 while VEGFmax was marginally influential. A +20 % change in Td, VD-nt and VEGFmax resulted in +50%, +25% and +5% increase in peak pO2. In contrast, Td was the most influential on the time to peak oxygenation with VD-nt and VEGFmax playing marginal roles. A +20% change in Td, VD-nt and VEGFmax increased the time to peak pO2 by +50%, +5% and +0%. A −20% change in the above parameters resulted in comparable decreases in the peak and time to peak pO2. Model application to the PET data was able to demonstrate the voxel-specific changes in hypoxia of the imaged tumor. Conclusion: Tumor-specific doubling time and vessel density are important parameters to be considered when evaluating hypoxia transients. While the current model simulates the oxygen dynamics of an untreated tumor, incorporation of therapeutic effects can make the model a potent tool for analyzing anti-angiogenic therapies.« less

Distribution of the planktonic shrimp Lucifer (Thompson, 1829) (Decapoda, Sergestoidea) off the Amazon.

PubMed

Melo, N F A C; Neumann-Leitão, S; Gusmão, L M O; Martins-Neto, F E; Palheta, G D A

2014-08-01

Lucifer faxoni (BORRADAILE, 1915) and L. typus (EDWARDS, 1837) are species first identified in the neritic and oceanic waters off the Amazon. Samplings were made aboard the vessel "Antares" at 22 stations in July and August, 2001 with a bongo net (500-µm mesh size). Hydrological data were taken simultaneously for comparative purposes. L. faxoni was present at thirteen of the fourteen neritic stations analysed, as well as at five of the eight oceanic stations. L. typus was present at three of the fourteen neritic stations and in one of the eight oceanic stations. The highest density of L. faxoni in the neritic province was 7,000 ind.m(-3) (St. 82) and 159 ind.m(-3) (St. 75) in the oceanic area. For L. typus, the highest density observed was 41 ind.m(-3) (St. 64) in the neritic province. In the oceanic province, the highest single density value was recorded at station 75 (5 ind.m(-3)). Overall, L. faxoni typically presented the highest densities.

Xylem anatomy correlates with gas exchange, water-use efficiency and growth performance under contrasting water regimes: evidence from Populus deltoides x Populus nigra hybrids.

PubMed

Fichot, Régis; Laurans, Françoise; Monclus, Romain; Moreau, Alain; Pilate, Gilles; Brignolas, Franck

2009-12-01

Six Populus deltoides Bartr. ex Marsh. x P. nigra L. genotypes were selected to investigate whether stem xylem anatomy correlated with gas exchange rates, water-use efficiency (WUE) and growth performance. Clonal copies of the genotypes were grown in a two-plot common garden test under contrasting water regimes, with one plot maintained irrigated and the other one subjected to moderate summer water deficit. The six genotypes displayed a large range of xylem anatomy, mean vessel and fibre diameter varying from about 40 to 60 microm and from 7.5 to 10.5 microm, respectively. Decreased water availability resulted in a reduced cell size and an important rise in vessel density, but the extent of xylem plasticity was both genotype and trait dependent. Vessel diameter and theoretical xylem-specific hydraulic conductivity correlated positively with stomatal conductance, carbon isotope discrimination and growth performance-related traits and negatively with intrinsic WUE, especially under water deficit conditions. Vessel diameter and vessel density measured under water deficit conditions correlated with the relative losses in biomass production in response to water deprivation; this resulted from the fact that a more plastic xylem structure was generally accompanied by a larger loss in biomass production.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milgram, J.; Erb, P.R.

A study of the behavior of floating drilling vessels during blowouts included: (1) a survey of actual incidents, (2) development of a computer model of a vessel in a blowout, and (3) large-scale experiments with a floating object in a bubble plume. The results disproved the common belief that a floating vessel will sink suddenly if a subsea blowout occurs below it. Actually, the average vertical support force changes very little in a blowout; in fact, a net upward force may result if the upwelling water flow overcomes the slight loss of fluid density due to bubbles. However, the currentsmore » caused by a blowout plume can make the vessel tip or oscillate.« less

Long-term streptozotocin-induced diabetes in rats leads to severe damage of brain blood vessels and neurons via enhanced oxidative stress.

PubMed

Yang, Hongying; Fan, Shourui; Song, Dianping; Wang, Zhuo; Ma, Shungao; Li, Shuqing; Li, Xiaohong; Xu, Mian; Xu, Min; Wang, Xianmo

2013-02-01

The aim of this study was to investigate pathophysiological alterations and oxidative stress in various stages of streptozotocin (STZ)‑induced diabetes mellitus (DM) in rats. Male Sprague-Dawley rats (120) were randomized into DM and control groups. Body mass, plasma glucose, glycated hemoglobin (HbA1c), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) levels, as well as aldose reductase (AR) activities, in brain tissue and serum were determined. Electron microscopy was used to observe neuron and vessel changes in the brain. In STZ‑treated rats, blood glucose, low density lipoproteins, triglycerides and total cholesterol levels increased 1.43‑3.0‑fold and high density lipoprotein, HbA1c and insulin sensitivity index increased 1.1‑1.23‑fold compared with control. At week 16 following treatment, DM rat serum H2O2 concentration was increased, indicating oxidative stress and mRNA levels of GPx and SOD were 2‑fold higher than the control. Protein GPx and SOD levels were reduced (P<0.01). DM rats were identified to exhibit early irregular glomerular capillary basement membrane thickening and vacuolization in the mitochondria and epithelial cells. Neuron cells and blood vessels in the DM rat brains became increasingly abnormal over time with altered Golgi bodies, mitochondria and endoplasmic reticulum cisterns, concurrent with SOD inactivation and AR protein accumulation. Disease progression in rats with STZ‑induced DM included brain pathologies with vascular and neuron cell abnormalities, associated with the reduction of SOD, CAT and GPx activities and also AR accumulation.

Histomorphometric analysis of collagen architecture of auricular keloids in an Asian population.

PubMed

Chong, Yosep; Park, Tae Hwan; Seo, Sang won; Chang, Choong Hyun

2015-03-01

Keloids are a pathologic condition of the reparative process, which present as excessive scar formation that involves various cells and cytokines. Many studies focusing on the histologic feature of keloids, however, have shown discordant results without consideration of architectural aspect of collagen structure. The purpose of this study was to demonstrate a schematic illustration of collagen architecture of keloids, specifically auricular keloids, and to analyze each part on the histomorphologic and morphometric basis. Thirty-nine surgically excised auricular keloids were retrieved from the file of Kangbuk Samsung Hospital. After exhaustive histomorphologic analysis, 3 distinctive structural parts, keloidal collagen, organizing collagen, and proliferating core collagen, were identified and mapped in every case. Cellularity of fibroblasts, blood vessel density, degree of inflammatory cell infiltration, and mast cells counts using Masson trichrome stain, Van Gieson stain, toluidine blue stain, and immunohistochemical stains for CD31 and smooth muscle actin were analyzed in each part of each case. Morphometric analysis on these parameters using ImageJ software was performed using 3 representative images of each part. Three parts were histomorphologically distinct by shape and array of collagen bundles, fibroblasts cellularity, blood vessel density, degree of inflammatory cells, and mast cell infiltration. Morphometric analysis revealed statistically significant difference between each part in fibroblasts cellularity, blood vessel density, degree of inflammatory cell infiltration, and mast cells count. All parameters were exceedingly high in whorling hypercellular fibrous nodules in proliferating core collagen showing simultaneous changes in other parts. Morphologically and morphometrically, 3 distinctive parts were identified in auricular keloids. Mast cell infiltrations, blood vessel density, and fibroblast cellularity are simultaneously increased or decreased according to these parts. Proliferating core collagen might serve as a proliferating center of keloids and might be a key portion for tumor growth and recurrence.

10 GY TOTAL BODY IRRADIATION INCREASES RISK OF CORONARY SCLEROSIS, DEGENERATION OF HEART STRUCTURE AND FUNCTION IN A RAT MODEL

PubMed Central

Baker, John E; Fish, Brian L; Su, Jidong; Haworth, Steven T; Strande, Jennifer L; Komorowski, Richard A; Migrino, Raymond Q; Doppalapudi, Anil; Harmann, Leanne; Li, X Allen; Hopewell, John W; Moulder, John E

2009-01-01

Purpose To determine the impact of 10 Gy total body irradiation (TBI) or local thorax irradiation, a dose relevant to a radiological terrorist threat, on lipid and liver profile, coronary microvasculature and ventricular function. Materials and methods WAG/RijCmcr rats received 10 Gy TBI followed by bone marrow transplantation, or 10 Gy local thorax irradiation. Age-matched, non-irradiated rats served as controls. The lipid profile and liver enzymes, coronary vessel morphology, nitric oxide synthase (NOS) isoforms, protease activated receptor (PAR)-1 expression and fibrinogen levels were compared. Two dimensional strain echocardiography assessed global radial and circumferential strain on the heart. Results TBI resulted in a sustained increase in total and low density lipoprotein (LDL) cholesterol (190±8 vs. 58±6; 82±8 vs. 13±3 mg/dL, respectively). The density of small coronary arterioles was decreased by 32%. Histology revealed complete blockage of some vessels while cardiomyocytes remained normal. TBI resulted in cellular peri-arterial fibrosis whereas control hearts had symmetrical penetrating vessels with less collagen and fibroblasts. TBI resulted in a 32±4% and 28±3% decrease in endothelial NOS and inducible NOS protein respectively, and a 21±4% and 35±5% increase in fibrinogen and PAR-1 protein respectively, after 120 days. TBI reduced radial strain (19±8 vs. 46±7%) and circumferential strain (-8±3 vs. −15±3%) compared to controls. Thorax-only irradiation produced no changes over the same time frame. Conclusions TBI with 10 Gy, a dose relevant to radiological terrorist threats, worsened lipid profile, injured coronary microvasculature, altered endothelial physiology and myocardial mechanics. These changes were not manifest with local thorax irradiation. Non-thoracic circulating factors may be promoting radiation-induced injury to the heart. PMID:19995235

Increased blood flow and vasculature in solar lentigo.

PubMed

Hasegawa, Kiyotaka; Fujiwara, Rumiko; Sato, Kiyoshi; Park, Ji-Youn; Kim, Sang Jin; Kim, Misun; Kang, Hee Young

2016-10-01

Solar lentigo (SL) is a hallmark of ultraviolet (UV)-induced photoaged skin and growing evidence implicates blood vessels in UV-associated pigmentation. In this study, we investigated whether the vasculatures are modified in SL. Twenty-five women with facial SL were enrolled and colorimetric and blood flow studies were performed. There was a significant increase in erythema which was associated with increased blood flow in the lesional skin compared with perilesional normal skin. Immunohistochemical studies with 24 facial SL biopsies consistently revealed a significant increase in vessel density accompanied by increased levels of vascular endothelial growth factor expression. CD68 immunoreactivity was significantly higher in lesional skin suggesting increased macrophage infiltration in SL. In conclusion, SL is characterized by increased blood flow and vasculature. These findings suggest the possible influence of the characteristics of vasculature on development of SL. © 2016 Japanese Dermatological Association.

In-service Inspection Ultrasonic Testing of Reactor Pressure Vessel Welds for Assessing Flaw Density and Size Distribution per 10 CFR 50.61a, Alternate Fracture Toughness Requirements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Edmund J.; Anderson, Michael T.; Norris, Wallace

2012-09-17

Pressurized thermal shock (PTS) events are system transients in a pressurized water reactor (PWR) in which there is a rapid operating temperature cool-down that results in cold vessel temperatures with or without repressurization of the vessel. The rapid cooling of the inside surface of the reactor pressure vessel (RPV) causes thermal stresses that can combine with stresses caused by high pressure. The aggregate effect of these stresses is an increase in the potential for fracture if a pre-existing flaw is present in a material susceptible to brittle failure. The ferritic, low alloy steel of the reactor vessel beltline adjacent tomore » the core, where neutron radiation gradually embrittles the material over the lifetime of the plant, can be susceptible to brittle fracture. The PTS rule, described in the Code of Federal Regulations, Title 10, Section 50.61 (§50.61), “Fracture Toughness Requirements for Protection against Pressurized Thermal Shock Events,” adopted on July 23, 1985, establishes screening criteria to ensure that the potential for a reactor vessel to fail due to a PTS event is deemed to be acceptably low. The U.S. Nuclear Regulatory Commission (NRC) completed a research program that concluded that the risk of through-wall cracking due to a PTS event is much lower than previously estimated. The NRC subsequently developed a rule, §50.61a, published on January 4, 2010, entitled “Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events” (75 FR 13). Use of the new rule by licensees is optional. The §50.61a rule differs from §50.61 in that it requires licensees who choose to follow this alternate method to analyze the results from periodic volumetric examinations required by the ASME Code, Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plants. These analyses are intended to determine if the actual flaw density and size distribution in the licensee’s reactor vessel beltline welds are bounded by the flaw density and size distribution values used in the PTS technical basis. Under a contract with the NRC, Pacific Northwest National Laboratory (PNNL) has been working on a program to assess the ability of current inservice inspection (ISI)-ultrasonic testing (UT) techniques, as qualified through ASME Code, Appendix VIII, Supplements 4 and 6, to detect small fabrication or inservice-induced flaws located in RPV welds and adjacent base materials. As part of this effort, the investigators have pursued an evaluation, based on the available information, of the capability of UT to provide flaw density/distribution inputs for making RPV weld assessments in accordance with §50.61a. This paper presents the results of an evaluation of data from the 1993 Browns Ferry Nuclear Plant, Unit 3, Spirit of Appendix VIII reactor vessel examination, a comparison of the flaw density/distribution from this data with the distribution in §50.61a, possible reasons for differences, and plans and recommendations for further work in this area.« less

Encoding Hydrogel Mechanics via Network Cross-Linking Structure.

PubMed

Schweller, Ryan M; West, Jennifer L

2015-05-11

The effects of mechanical cues on cell behaviors in 3D remain difficult to characterize as the ability to tune hydrogel mechanics often requires changes in the polymer density, potentially altering the material's biochemical and physical characteristics. Additionally, with most PEG diacrylate (PEGDA) hydrogels, forming materials with compressive moduli less than ∼10 kPa has been virtually impossible. Here, we present a new method of controlling the mechanical properties of PEGDA hydrogels independent of polymer chain density through the incorporation of additional vinyl group moieties that interfere with the cross-linking of the network. This modification can tune hydrogel mechanics in a concentration dependent manner from <1 to 17 kPa, a more physiologically relevant range than previously possible with PEG-based hydrogels, without altering the hydrogel's degradation and permeability. Across this range of mechanical properties, endothelial cells (ECs) encapsulated within MMP-2/MMP-9 degradable hydrogels with RGDS adhesive peptides revealed increased cell spreading as hydrogel stiffness decreased in contrast to behavior typically observed for cells on 2D surfaces. EC-pericyte cocultures exhibited vessel-like networks within 3 days in highly compliant hydrogels as compared to a week in stiffer hydrogels. These vessel networks persisted for at least 4 weeks and deposited laminin and collagen IV perivascularly. These results indicate that EC morphogenesis can be regulated using mechanical cues in 3D. Furthermore, controlling hydrogel compliance independent of density allows for the attainment of highly compliant mechanical regimes in materials that can act as customizable cell microenvironments.

High-Accuracy Ultrasound Contrast Agent Detection Method for Diagnostic Ultrasound Imaging Systems.

PubMed

Ito, Koichi; Noro, Kazumasa; Yanagisawa, Yukari; Sakamoto, Maya; Mori, Shiro; Shiga, Kiyoto; Kodama, Tetsuya; Aoki, Takafumi

2015-12-01

An accurate method for detecting contrast agents using diagnostic ultrasound imaging systems is proposed. Contrast agents, such as microbubbles, passing through a blood vessel during ultrasound imaging are detected as blinking signals in the temporal axis, because their intensity value is constantly in motion. Ultrasound contrast agents are detected by evaluating the intensity variation of a pixel in the temporal axis. Conventional methods are based on simple subtraction of ultrasound images to detect ultrasound contrast agents. Even if the subject moves only slightly, a conventional detection method will introduce significant error. In contrast, the proposed technique employs spatiotemporal analysis of the pixel intensity variation over several frames. Experiments visualizing blood vessels in the mouse tail illustrated that the proposed method performs efficiently compared with conventional approaches. We also report that the new technique is useful for observing temporal changes in microvessel density in subiliac lymph nodes containing tumors. The results are compared with those of contrast-enhanced computed tomography. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Standard High Solids Vessel Design De-inventory Simulant Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiskum, Sandra K.; Burns, Carolyn A.M.; Gauglitz, Phillip A.

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is working to develop a Standard High Solids Vessel Design (SHSVD) process vessel. To support testing of this new design, WTP engineering staff requested that a Newtonian simulant be developed that would represent the de-inventory (residual high-density tank solids cleanout) process. Its basis and target characteristics are defined in 24590-WTP-ES-ENG-16-021 and implemented through PNNL Test Plan TP-WTPSP-132 Rev. 1.0. This document describes the de-inventory Newtonian carrier fluid (DNCF) simulant composition that will satisfy the basis requirement to mimic the density (1.18 g/mL ± 0.1 g/mL) and viscosity (2.8 cP ± 0.5more » cP) of 5 M NaOH at 25 °C.1 The simulant viscosity changes significantly with temperature. Therefore, various solution compositions may be required, dependent on the test stand process temperature range, to meet these requirements. Table ES.1 provides DNCF compositions at selected temperatures that will meet the density and viscosity specifications as well as the temperature range at which the solution will meet the acceptable viscosity tolerance.« less

Three-dimensional imaging of absolute blood flow velocity and blood vessel position under low blood flow velocity based on Doppler signal information included in scattered light from red blood cells

NASA Astrophysics Data System (ADS)

Kyoden, Tomoaki; Akiguchi, Shunsuke; Tajiri, Tomoki; Andoh, Tsugunobu; Hachiga, Tadashi

2017-11-01

The development of a system for in vivo visualization of occluded distal blood vessels for diabetic patients is the main target of our research. We herein describe two-beam multipoint laser Doppler velocimetry (MLDV), which measures the instantaneous multipoint flow velocity and can be used to observe the blood flow velocity in peripheral blood vessels. By including a motorized stage to shift the measurement points horizontally and in the depth direction while measuring the velocity, the path of the blood vessel in the skin could be observed using blood flow velocity in three-dimensional space. The relationship of the signal power density between the blood vessel and the surrounding tissues was shown and helped us identify the position of the blood vessel. Two-beam MLDV can be used to simultaneously determine the absolute blood flow velocity distribution and identify the blood vessel position in skin.

Functional evaluation of sublingual microcirculation indicates successful weaning from VA-ECMO in cardiogenic shock.

PubMed

Akin, Sakir; Dos Reis Miranda, Dinis; Caliskan, Kadir; Soliman, Osama I; Guven, Goksel; Struijs, Ard; van Thiel, Robert J; Jewbali, Lucia S; Lima, Alexandre; Gommers, Diederik; Zijlstra, Felix; Ince, Can

2017-10-26

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly adopted for the treatment of cardiogenic shock (CS). However, a marker of successful weaning remains largely unknown. Our hypothesis was that successful weaning is associated with sustained microcirculatory function during ECMO flow reduction. Therefore, we sought to test the usefulness of microcirculatory imaging in the same sublingual spot, using incident dark field (IDF) imaging in assessing successful weaning from VA-ECMO and compare IDF imaging with echocardiographic parameters. Weaning was performed by decreasing the VA-ECMO flow to 50% (F 50 ) from the baseline. The endpoint of the study was successful VA-ECMO explantation within 48 hours after weaning. The response of sublingual microcirculation to a weaning attempt (WA) was evaluated. Microcirculation was measured in one sublingual area (single spot (ss)) using CytoCam IDF imaging during WA. Total vessel density (TVDss) and perfused vessel density (PVDss) of the sublingual area were evaluated before and during 50% flow reduction (TVDss F50 , PVDss F50 ) after a WA and compared to conventional echocardiographic parameters as indicators of the success or failure of the WA. Patients (n = 13) aged 49 ± 18 years, who received VA-ECMO for the treatment of refractory CS due to pulmonary embolism (n = 5), post cardiotomy (n = 3), acute coronary syndrome (n = 2), myocarditis (n = 2) and drug intoxication (n = 1), were included. TVDss F50 (21.9 vs 12.9 mm/mm 2 , p = 0.001), PVDss F50 (19.7 vs 12.4 mm/mm 2 , p = 0.01) and aortic velocity-time integral (VTI) at 50% flow reduction (VTI F50 ) were higher in patients successfully weaned vs not successfully weaned. The area under the curve (AUC) was 0.99 vs 0.93 vs 0.85 for TVDss F50 (small vessels) >12.2 mm/mm 2 , left ventricular ejection fraction (LVEF) >15% and aortic VTI >11 cm. Likewise, the AUC was 0.91 vs 0.93 vs 0.85 for the PVDss F50 (all vessels) >14.8 mm/mm 2 , LVEF >15% and aortic VTI >11 cm. This study identified sublingual microcirculation as a novel potential marker for identifying successful weaning from VA-ECMO. Sustained values of TVDss F50 and PVDss F50 were found to be specific and sensitive indicators of successful weaning from VA-ECMO as compared to echocardiographic parameters.

Effect of Intravitreal Bevacizumab on Vascular Endothelial Growth Factor Expression in Patients with Proliferative Diabetic Retinopathy

PubMed Central

Chung, Eun Jee; Kang, Shin Jeong; Koo, Ja Seung; Choi, Yoon Jung; Grossniklaus, Hans E.

2011-01-01

Purpose To investigate the effect of bevacizumab (Avastin; Genentech, San Francisco, CA, USA) on vascular endothelial growth factor (VEGF) expression and inflammation in fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR). Materials and Methods Fibrovascular membranes from 19 eyes of 18 patients with PDR were studied using immunohistochemistry and analyzed in the following 3 groups; group 1: 4 inactive PDR eyes, group 2: 10 active PDR eyes treated preoperatively with adjunctive intravitreal bevacizumab, group 3: five active PDR eyes not treated preoperatively with bevacizumab. Immunohistochemical staining for VEGF, CD31 and CD68 were done. Results The immunoreactivity to VEGF and CD 31-positive blood vessels was significantly higher in membranes from group 3 than group 1 (p = 0.007 for VEGF, 0.013 for CD 31-positive vessels). Intravitreal bevacizumab caused a reduction in VEGF expression and vascular densities in 4 out of 10 (40%) excised membranes from eyes with PDR. However, six membranes (60%) in group 2 still demonstrated relatively strong VEGF expression and high vascular density. Infiltration of macrophages was observed in 16 out of the 19 membranes, and the density of macrophages was increased in group 2 compared with group 1 (p = 0.043). Conclusion Intravitreal bevacizumab injections caused some reduction in VEGF expression and vascular densities in a limited number of active PDR patients. A single intravitreal bevacizumab injection may not be enough to induce complete blockage of VEGF and pathologic neovascularization in active PDR patients. Repeated injections, panretinal photocoagulation and/or PPV may be necessary following intravitreal bevacizumab to reinforce the anti-VEGF effect of the drug. PMID:21155048

Placement of trans-sternal wires according to an ellipsoid pressure vessel model of sternal forces.

PubMed

Casha, Aaron R; Manché, Alex; Gauci, Marilyn; Camilleri-Podesta, Marie-Therese; Schembri-Wismayer, Pierre; Sant, Zdenka; Gatt, Ruben; Grima, Joseph N

2012-03-01

Dehiscence of median sternotomy wounds remains a clinical problem. Wall forces in thin-walled pressure vessels can be calculated by membrane stress theory. An ellipsoid pressure vessel model of sternal forces is presented together with its application for optimal wire placement in the sternum. Sternal forces were calculated by computational simulation using an ellipsoid chest wall model. Sternal forces were correlated with different sternal thicknesses and radio-density as measured by computerized tomography (CT) scans of the sternum. A comparison of alternative placement of trans-sternal wires located either at the levels of the costal cartilages or the intercostal spaces was made. The ellipsoid pressure vessel model shows that higher levels of stress are operative at increasing chest diameter (P < 0.001). CT scans show that the thickness of the sternal body is on average 3 mm and 30% thicker (P < 0.001) and 53% more radio-dense (P < 0.001) at the costal cartilage levels when compared with adjacent intercostal spaces. This results in a decrease of average sternal stress from 438 kPa at the intercostal space level to 338 kPa at the costal cartilage level (P = 0.003). Biomechanical modelling suggests that placement of trans-sternal wires at the thicker bone and more radio-dense level of the costal cartilages will result in reduced stress.

Evaluation of the Zeiss retinal vessel analyser

PubMed Central

Polak, K.; Dorner, G.; Kiss, B.; Polska, E.; Findl, O.; Rainer, G.; Eichler, H.; Schmetterer, L.

2000-01-01

AIM—To investigate the reproducibility and sensitivity of the Zeiss retinal vessel analyser, a new method for the online determination of retinal vessel diameters in healthy subjects.
METHODS—Two model drugs were administered, a peripheral vasoconstrictor (the α receptor agonist phenylephrine) and a peripheral vasodilator (the nitric oxide donor sodium nitroprusside) in stepwise increasing doses. Nine healthy young subjects were studied in a placebo controlled double masked three way crossover design. Subjects received intravenous infusions of either placebo or stepwise increasing doses of phenylephrine (0.5, 1, or 2 µg/kg/min) or sodium nitroprusside (0.5, 1, or 2 µg/kg/min). Retinal vessel diameters were measured with the new Zeiss retinal vessel analyser. Retinal leucocyte velocity, flow, and density were measured with the blue field entoptic technique. The reproducibility of measurements was assessed with coefficients of variation and intraclass correlation coefficients.
RESULTS—Placebo and phenylephrine did not influence retinal haemodynamics, although the α receptor antagonist significantly increased blood pressure. Sodium nitroprusside induced a significant increase in retinal venous and arterial diameters (p<0.001 each), leucocyte density (p=0.001), and leucocyte flow (p=0.024) despite lowering blood pressure to a significant degree. For venous and arterial vessel size measurements short term coefficients of variation were 1.3% and 2.6% and intraclass correlation coefficients were 0.98 and 0.96, respectively. The sensitivity was between 3% and 5% for retinal veins and 5% and 7% for retinal arteries.
CONCLUSIONS—These data indicate that the Zeiss retinal vessel analyser is an accurate system for the assessment of retinal diameters in healthy subjects. In addition, nitric oxide appears to have a strong influence on retinal vascular tone.

 PMID:11049956

Estrogen receptor expression and vessel density in the vagina wall in postmenopausal women with prolapse.

PubMed

Lara, Lúcia Alves da Silva; Ribeiro da Silva, Alfredo; Rosa-e-Silva, Julio Cesar; Silva-de-Sá, Marcos Felipe; Rosa-e-Silva, Ana Carolina Japur de Sá

2014-04-01

After menopause, critically estrogen low levels result in modifications in vaginal wall. This cross-sectional study aims to determine whether there is a change in the number of vessels in the lamina propria of the vagina after menopause in parallel to the ER-alpha expression on the vaginal wall. Twelve women who underwent a genital surgery for genital prolapse up to grade II were selected. They were divided into two groups: a premenopausal group (PG) consisting of six women who were 18-40 years old with FSH levels =12 mIU/ml and regular cycles, and a menopausal group (MG) consisting of six women at least one year after menopause who were <65 years old with FSH levels =40 mIU/ml. Slides were stained for ER-alpha immunohistochemistry, and an endothelial cell marker CD3 was used to label vessels which were identified by using a system for morphometry. The number of vessels was significantly higher in the PG than in the MG both on the anterior wall (PG: 1.055 ± 145.8 vessels/mm(2), MG: 346.6 ± 209.9 vessels/mm(2), p<0.0001) and on the posterior wall (PG: 1064 ± 303.3 vessels/mm(2), MG: 348.6 ± 167.3 vessels/mm(2), p=0.0005). The ER-alpha score was significantly higher in the PG than the score for the MG on both the anterior and posterior walls (PG: 6.0 ± 0.52, MG: 2.5 ± 0.89, p=0.007; PG: 5.8 ± 0.79, MG: 2.7 ± 0.95, p=0.03, respectively). There was a positive correlation between the ER-alpha score and the vessel concentration on the anterior (r=0.6656, p=0.018) and posterior (r=0.6738, p=0.016) vaginal walls. Age was strongly negatively correlated with vessel concentration on the vaginal walls (respectively r=-0.9033, p<0.0001, r=-0.7440, p=0.0055). Therefore, postmenopausal women with genital prolapse have a smaller number of vessels on the vaginal wall compared to normoestrogenic controls with the same pathological condition. Hypoestrogenism and advancing age are factors that are associated to these changes. Copyright © 2014 Elsevier Ltd. All rights reserved.

MACULAR MICROVASCULAR NETWORKS IN HEALTHY PEDIATRIC SUBJECTS.

PubMed

Borrelli, Enrico; Lonngi, Marcela; Balasubramanian, Siva; Tepelus, Tudor C; Baghdasaryan, Elmira; Iafe, Nicholas A; Pineles, Stacy L; Velez, Federico G; Sarraf, David; Sadda, SriniVas R; Tsui, Irena

2018-02-22

To report optical coherence tomography angiography (OCTA) values in healthy pediatric eyes and to identify factors that may modify these values. In this prospective observational cross-sectional study, macular OCTA images were acquired from healthy pediatric patients. Main outcome measures were 1) foveal avascular zone (FAZ) area at the level of the superficial retinal capillary plexus (SCP); 2) SCP and deep retinal capillary plexus (DCP) perfusion density (based on the area of vessels); 3) SCP and DCP vessel density (based on a map with vessels of 1-pixel width); and 4) CC perfusion density. Multiple regression analysis was performed to assess the effect of age, sex, ethnicity, refraction, and foveal macular thickness (FMT) on OCTA parameters. Seventy-seven eyes from 52 subjects (23 male and 29 female) were included in analysis. Mean age was 11.1 ± 3.3 years (range = 5.0-17.0 years). Twenty-nine (55.8%) subjects were white, 14 (27.0%) Hispanic, 8 (15.4%) Asian, and 1 (1.8%) African-American. Mean refraction was -0.1 ± 2.4 diopters (D) (range = -5.75 to +9.0 D). Mean FMT was 248.6 ± 18.6 μm. Larger FAZ area was significantly associated with older age (P = 0.014). Furthermore, larger FAZ area was associated with reduced FMT (P < 0.0001). Male sex was associated only with increased SCP perfusion density (P = 0.042). Increased CC perfusion density was associated with younger age (P = 0.022). We report data for pediatric OCTA parameters in healthy subjects. Several variables influence the density of macular microvascular networks, and these factors should be considered in the OCTA study of pediatric eye disorders.

Assessment of capillary dropout in the superficial retinal capillary plexus by optical coherence tomography angiography in the early stage of diabetic retinopathy.

PubMed

Shen, Ceying; Yan, Shu; Du, Min; Zhao, Hong; Shao, Ling; Hu, Yibo

2018-05-08

To assess capillary dropout in the superficial retinal capillary plexus (SCP) by optical coherence tomography angiography (OCTA) in the early stage of diabetic retinopathy (DR). This study was a cross-sectional observational study. Patients that underwent OCTA examinations in our hospital between November 2015 and May 2016 were included in the study. The subjects were divided into two groups: A) normal controls (41 eyes of 41 subjects) and B) the DR patients (49 eyes of 49 patients with mild non-proliferative DR (NPDR)). The retinal thickness and SCP vessel density were analyzed using built-in software in nine sections of the macular area; whole scan area; fovea; parafovea; and sub-sections of the parafovea, superior-hemi, inferior-hemi, temporal, superior, nasal, and inferior. The correlation between vessel density and retinal thickness was also analyzed. The SCP density was significantly lower (P < 0.05) in mild NPDR patients than in normal controls in all areas, with the exception of the fovea (P > 0.05). In the parafovea, superior-hemi, inferior-hemi, temporal, and nasal sectors of group B, the SCP density was negatively correlated with the corresponding retinal thickness (P < 0.05). Specifically, as the SCP density decreased, retinal thickness increased. In the early stage of NPDR, retinal capillary dropout and retinal thickness changes can be clearly captured and analyzed by OCTA. The results confirm a negative correlation between vessel density and retinal thickness in diabetic patients. This noninvasive technique could be applied for DR detection and monitoring. Further study with a larger sample size is warranted.

Noninvasive method for determining the liquid level and density inside of a container

DOEpatents

Sinha, Dipen N.

2000-01-01

Noninvasive method for determining the liquid level and density inside of a container having arbitrary dimension and shape. By generating a flexural acoustic wave in the container shell and measuring the phase difference of the detected flexural wave from that of the originally generated wave a small distance from the generated wave, while moving the generation and detection means through the liquid/vapor interface, this interface can be detected. Both the wave generation and wave detection may be achieved by transducers on the surface of the container. A change in the phase difference over the outer surface of the vessel signifies that a liquid/vapor interface has been crossed, while the magnitude of the phase difference can be related to fluid density immediately opposite the measurement position on the surface of the vessel.

Angiogenesis and expression of vascular endothelial growth factor, tumour necrosis factor-α and hypoxia inducible factor-1α in canine renal cell carcinoma.

PubMed

Yhee, J Y; Yu, C H; Kim, J H; Im, K S; Kim, N H; Brodersen, B W; Doster, A R; Sur, J-H

2012-01-01

The aim of the present study was to determine the distribution and characteristics of microvessels in various histological types of canine renal cell carcinoma (RCC). The study compared microvessel density (MVD) and distribution of blood vessels according to histological type and evaluated the presence of angiogenesis-related proteins. Nine archival samples of canine RCC were studied. MVD was calculated as the mean number of blood vessels per mm(2). The diameter of blood vessels was calculated by determining either the length of the long axis of blood vessels (diameter(max)) or the mean distance from the centre of each blood vessel to the tunica adventia (diameter(mean)). A significant difference in MVD was evident between RCCs and normal kidneys (46.6 ± 28.0 versus 8.4 ± 2.2 microvessels/mm(2)). Diameter(max) in canine RCCs (34.1 ± 14.7 μm) was also significantly different from normal canine kidney (23.2 ± 3.4 μm). Vascular endothelial growth factor (VEGF) was expressed by tumour cells and vascular endothelial cells and tumour necrosis factor (TNF)-α expression was observed in vascular endothelial cells in both neoplastic and normal kidney. Although VEGF is involved in angiogenesis and correlates with tumour stage of development, no correlation was found between VEGF expression and MVD. Tumour-associated macrophages expressing TNF-α and hypoxia inducible factor 1α were identified in peritumoural tissue and may play an important role in angiogenesis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Browns Ferry Unit-3 cavity neutron spectral analysis. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, G.C.

1981-08-01

This report describes neutron dosimetry measurements performed in the Browns Ferry Unit-3 reactor cavity using multiple dosimeter and spectrum unfolding techniques to assess radiation-induced degradation of nuclear plant pressure vessels. Test results and conclusions indicating the feasibility of determining neutron flux spectra and the densities in the pressure vessel cavity region via dosimetric measurements are presented.

Cryo-image Analysis of Tumor Cell Migration, Invasion, and Dispersal in a Mouse Xenograft Model of Human Glioblastoma Multiforme

PubMed Central

Qutaish, Mohammed Q.; Sullivant, Kristin E.; Burden-Gulley, Susan M.; Lu, Hong; Roy, Debashish; Wang, Jing; Basilion, James P.; Brady-Kalnay, Susann M.; Wilson, David L.

2012-01-01

Purpose The goals of this study were to create cryo-imaging methods to quantify characteristics (size, dispersal, and blood vessel density) of mouse orthotopic models of glioblastoma multiforme (GBM) and to enable studies of tumor biology, targeted imaging agents, and theranostic nanoparticles. Procedures Green fluorescent protein-labeled, human glioma LN-229 cells were implanted into mouse brain. At 20–38 days, cryo-imaging gave whole brain, 4-GB, 3D microscopic images of bright field anatomy, including vasculature, and fluorescent tumor. Image analysis/visualization methods were developed. Results Vessel visualization and segmentation methods successfully enabled analyses. The main tumor mass volume, the number of dispersed clusters, the number of cells/cluster, and the percent dispersed volume all increase with age of the tumor. Histograms of dispersal distance give a mean and median of 63 and 56 μm, respectively, averaged over all brains. Dispersal distance tends to increase with age of the tumors. Dispersal tends to occur along blood vessels. Blood vessel density did not appear to increase in and around the tumor with this cell line. Conclusion Cryo-imaging and software allow, for the first time, 3D, whole brain, microscopic characterization of a tumor from a particular cell line. LN-229 exhibits considerable dispersal along blood vessels, a characteristic of human tumors that limits treatment success. PMID:22125093

Evaluation of Microvascular Perfusion and Resuscitation after Severe Injury.

PubMed

Lee, Yann-Leei L; Simmons, Jon D; Gillespie, Mark N; Alvarez, Diego F; Gonzalez, Richard P; Brevard, Sidney B; Frotan, Mohammad A; Schneider, Andrew M; Richards, William O

2015-12-01

Achieving adequate perfusion is a key goal of treatment in severe trauma; however, tissue perfusion has classically been measured by indirect means. Direct visualization of capillary flow has been applied in sepsis, but application of this technology to the trauma population has been limited. The purpose of this investigation was to compare the efficacy of standard indirect measures of perfusion to direct imaging of the sublingual microcirculatory flow during trauma resuscitation. Patients with injury severity scores >15 were serially examined using a handheld sidestream dark-field video microscope. In addition, measurements were also made from healthy volunteers. The De Backer score, a morphometric capillary density score, and total vessel density (TVD) as cumulative vessel area within the image, were calculated using Automated Vascular Analysis (AVA3.0) software. These indices were compared against clinical and laboratory parameters of organ function and systemic metabolic status as well as mortality. Twenty severely injured patients had lower TVD (X = 14.6 ± 0.22 vs 17.66 ± 0.51) and De Backer scores (X = 9.62 ± 0.16 vs 11.55 ± 0.37) compared with healthy controls. These scores best correlated with serum lactate (TVD R(2) = 0.525, De Backer R(2) = 0.576, P < 0.05). Mean arterial pressure, heart rate, oxygen saturation, pH, bicarbonate, base deficit, hematocrit, and coagulation parameters correlated poorly with both TVD and De Backer score. Direct measurement of sublingual microvascular perfusion is technically feasible in trauma patients, and seems to provide real-time assessment of microcirculatory perfusion. This study suggests that in severe trauma, many indirect measurements of perfusion do not correlate with microvascular perfusion. However, visualized perfusion deficiencies do reflect a shift toward anaerobic metabolism.

Dienogest reduces proliferation, aromatase expression and angiogenesis, and increases apoptosis in human endometriosis.

PubMed

Miyashita, Mariko; Koga, Kaori; Takamura, Masashi; Izumi, Gentaro; Nagai, Miwako; Harada, Miyuki; Hirata, Tetsuya; Hirota, Yasushi; Fujii, Tomoyuki; Osuga, Yutaka

2014-09-01

Dienogest is a novel progestin that is highly selective for progesterone receptors and inhibits endometriosis. However, it remains unknown how the administration of dienogest to patients with endometriosis impacts on their lesion tissues. The aim of this study was to evaluate the in vivo effect of dienogest on endometriosis tissue. We collected endometrioma tissues from patients treated with dienogest (N = 7) or not treated (N = 11, controls). Cell proliferation, aromatase expression and blood vessel density were evaluated by staining for Ki67, aromatase and the von Willebrand factor, respectively. Apoptosis was detected using the TUNEL assay. The proportion of Ki67 and aromatase positive epithelial cells was significantly lower in the dienogest group than in controls (p < 0.05, respectively). The number of TUNEL positive cells was significantly higher in the dienogest group (p < 0.05). The density of blood vessels in endometrioma was marginally lower in the dienogest group compared with controls (p = 0.20). Our study demonstrates that endometrioma taken from patients treated with dienogest show remarkable histological features such as reduction of proliferation, aromatase expression and angiogenesis, and increase of apoptosis. This study clarified the impact of dienogest on local histological events that explain its therapeutic effect on endometriosis.

Blood-brain barrier leakage after status epilepticus in rapamycin-treated rats II: Potential mechanisms.

PubMed

van Vliet, Erwin A; Otte, Willem M; Wadman, Wytse J; Aronica, Eleonora; Kooij, Gijs; de Vries, Helga E; Dijkhuizen, Rick M; Gorter, Jan A

2016-01-01

Blood-brain barrier (BBB) leakage may play a pro-epileptogenic role after status epilepticus. In the accompanying contrast-enhanced magnetic resonance imaging (CE-MRI) study we showed that the mammalian target of rapamycin (mTOR) inhibitor rapamycin reduced BBB leakage and seizure activity during the chronic epileptic phase. Given rapamycin's role in growth and immune response, the potential therapeutic effects of rapamycin after status epilepticus with emphasis on brain inflammation and brain vasculature were investigated. Seven weeks after kainic acid-induced status epilepticus, rats were perfusion fixed and (immuno)histochemistry was performed using several glial and vascular markers. In addition, an in vitro model for the human BBB was used to determine the effects of rapamycin on transendothelial electrical resistance as a measure for BBB integrity. (Immuno)histochemistry showed that local blood vessel density, activated microglia, and astrogliosis were reduced in rapamycin-treated rats compared to vehicle-treated rats. In vitro studies showed that rapamycin could attenuate TNFα-induced endothelial barrier breakdown. These data suggest that rapamycin improves BBB function during the chronic epileptic phase by a reduction of local brain inflammation and blood vessel density that can contribute to a milder form of epilepsy. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

Increased Lymphatic Vessel Length Is Associated With the Fibroblast Reticulum and Disease Severity in Usual Interstitial Pneumonia and Nonspecific Interstitial Pneumonia

PubMed Central

Cosgrove, Gregory P.; Janssen, William J.; Huie, Tristan J.; Burnham, Ellen L.; Heinz, David E.; Curran-Everett, Douglas; Sahin, Hakan; Schwarz, Marvin I.; Cool, Carlyne D.; Groshong, Steve D.; Geraci, Mark W.; Tuder, Rubin M.; Hyde, Dallas M.; Henson, Peter M.

2012-01-01

Background: Lymphangiogenesis responds to tissue injury as a key component of normal wound healing. The development of fibrosis in the idiopathic interstitial pneumonias may result from abnormal wound healing in response to injury. We hypothesize that increased lymphatic vessel (LV) length, a marker of lymphangiogenesis, is associated with parenchymal components of the fibroblast reticulum (organizing collagen, fibrotic collagen, and fibroblast foci), and its extent correlates with disease severity. Methods: We assessed stereologically the parenchymal structure of fibrotic lungs and its associated lymphatic network, which was highlighted immunohistochemically in age-matched samples of usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP) with FVC < 80%, COPD with a Global Initiative for Obstructive Lung Disease stage 0, and normal control lungs. Results: LV length density, as opposed to vessel volume density, was found to be associated with organizing and fibrotic collagen density (P < .0001). Length density of LVs and the volume density of organizing and fibrotic collagen were significantly associated with severity of both % FVC (P < .001) and diffusing capacity of the lung for carbon monoxide (P < .001). Conclusions: Severity of disease in UIP and NSIP is associated with increased LV length and is strongly associated with components of the fibroblast reticulum, namely organizing and fibrotic collagen, which supports a pathogenic role of LVs in these two diseases. Furthermore, the absence of definable differences between UIP and NSIP suggests that LVs are a unifying mechanism for the development of fibrosis in these fibrotic lung diseases. PMID:22797508

Verapamil, a Calcium-Channel Blocker, Improves the Wound Healing Process in Rats with Excisional Full-Thickness Skin Wounds Based on Stereological Parameters.

PubMed

Ashkani-Esfahani, Soheil; Hosseinabadi, Omid Koohi; Moezzi, Parinaz; Moafpourian, Yalda; Kardeh, Sina; Rafiee, Shima; Fatheazam, Reza; Noorafshan, Ali; Nadimi, Elham; Mehrvarz, Shayan; Khoshneviszadeh, Mehdi; Khoshneviszadeh, Mahsima

2016-08-01

Calcium can play noticeable roles in the wound-healing process, such as its effects on organization of F-actinin collagen bundles by fibroblasts at the injury site. In addition, calcium-channel blockers such as verapamil have antioxidant activity by increasing nitric oxide production that promotes angiogenesis, proliferation of fibroblasts, and endothelial cells in the skin-regeneration process. Therefore, in this study, the authors' objective was to investigate the effects of verapamil on the process of wound healing in rat models according to stereological parameters. In this experimental study, 36 male Wistar rats were randomly divided into 3 groups (n = 12): the control group that received no treatment, gel-base-treated group, and the 5% verapamil gel-treated group. Treatments were done every 24 hours for 15 days. Wound closure rate, volume densities of the collagen bundles and the vessels, vessel's length density and mean diameter, and fibroblast populations were estimated using stereological methods and were analyzed by the Kruskal-Wallis and Mann-Whitney U tests; P < .05 was considered statistically significant. The verapamil-treated group showed a faster wound closure rate in comparison with control and gel-base groups (P = .007 and P = .011). The numerical density of fibroblasts, volume density of collagen bundles, mean diameter, and volume densities of the vessels in the verapamil group were significantly higher than those in the control and the base groups (P < .005). The authors showed that verapamil has the ability to improve wound healing by enhancing fibroblast proliferation, collagen bundle synthesis, and revascularization in skin injuries.

Regulatory Role of the NF-kB Pathway in Lymphangiogenesis and Breast Cancer Metastasis

DTIC Science & Technology

2010-07-01

with anti - LYVE-1 and anti -VEGFR-3 or anti -Prox1 antibodies in serial sections of p50 KO and WT lungs, showing reduced lymphatic vessel density...3 protein as determined by MFI analysis of slides double-stained with anti -VEGFR-3 and anti -LYVE-1 antibodies (Figure 2). These data indicate that...expression of VEGFR-3 and LYVE-1 on liver endothelial cells compared with WT. (A) Livers of p50 KO and WT mice were double immunostained with anti -VEGFR

46 CFR 98.25-65 - Filling density.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-65 - Filling density.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-65 - Filling density.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-65 - Filling density.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-65 - Filling density.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

Association of apolipoprotein E gene polymorphism with ischemic stroke involving large-vessel disease and its relation to serum lipid levels.

PubMed

Saidi, Sarra; Slamia, Lamia B; Ammou, Sofyan B; Mahjoub, Touhami; Almawi, Wassim Y

2007-01-01

A relationship between apolipoprotein E (Apo E) genotype and stroke was previously suggested, but with inconsistent results. We investigated the relationships among serum lipid levels, Apo E alleles and genotypes, and stroke risk factors in 216 stroke patients and 282 age- and sex-matched controls. Fasting blood samples were collected for total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride level determination and for genomic DNA extraction. Apo was genotyped by polymerase chain reaction-restriction fragment length polymorphism (Cfo I) analysis. Increasing levels of total cholesterol, LDL-C, HDL-C, and triglycerides were associated with elevated stroke risk and was more pronounced in Apo E4-carrying subjects than in E3- and/or E2-carrying subjects. Apo 3 was significantly lower (0.546 vs 0.736; P < .001), whereas Apo 4 was higher in the stroke patients (0.370 vs 0.181; P < .001); Apo 2 was present at low but comparable frequencies. The prevalence of E3/E3 was lower and that of E4-containing phenotypes (E3/E4 and homozygous E4/E4) was higher in the stroke patients. The prevalence of the E4-containing phenotypes were significantly higher in ischemic versus hemorrhagic (P < .001) and in small-vessel versus large-vessel stroke cases (P < .001), and was associated with increased need for statin drugs (P = .040). Logistic regression models, after adjusting for potentially confounding variables including lipid profile, age, and sex, showed an significant association of apo 4 genotype with risk of stroke (P = .033). Our findings indicate that Apo 4 is an independent risk factor associated with an altered lipid profile in this study population.

Peripapillary Retinal Nerve Fiber Layer Vascular Microcirculation in Eyes With Glaucoma and Single-Hemifield Visual Field Loss.

PubMed

Chen, Chieh-Li; Bojikian, Karine D; Wen, Joanne C; Zhang, Qinqin; Xin, Chen; Mudumbai, Raghu C; Johnstone, Murray A; Chen, Philip P; Wang, Ruikang K

2017-05-01

Understanding the differences in vascular microcirculation of the peripapillary retinal nerve fiber layer (RNFL) between the hemispheres in eyes with glaucoma with single-hemifield visual field (VF) defects may provide insight into the pathophysiology of glaucoma. To investigate the changes in the microcirculation of the peripapillary RNFL of eyes with glaucoma by using optical microangiography. Eyes with glaucoma and single-hemifield VF defect and normal eyes underwent scanning using an optical microangiography system covering a 6.7 × 6.7-mm2 area centered at the optic nerve head. The RNFL microcirculation was measured within an annulus region centered at the optic nerve head divided into superior and inferior hemispheres. Blood flux index (the mean flow signal intensity in the vessels) and vessel area density (the percentage of the detected vessels in the annulus) were measured. Differences in microcirculation between the hemispheres in eyes with glaucoma and normal eyes and correlations among blood flow metrics, VF thresholds, and clinical optical coherence tomography structural measurements were assessed. Twenty-one eyes from 21 patients with glaucoma (7 men and 14 women; mean [SD] age, 63.7 [9.9] years) and 20 eyes from 20 healthy control individuals (9 men and 11 women; mean [SD] age, 68.3 [10.7] years) were studied. In eyes with glaucoma, the abnormal hemisphere showed a thinner RNFL (mean [SE] difference, 23.5 [4.5] μm; 95% CI, 15.1-32.0 µm; P < .001), lower RNFL blood flux index (mean [SE] difference, 0.04 [0.01]; 95% CI, 0.02-0.05; P < .001), and less vessel area density (mean [SE] difference, 0.08% [0.02%]; 95% CI, 0.05%-0.10%; P < .001) than did the normal hemisphere. Compared with normal eyes, reduced RNFL microcirculation was found in the normal hemisphere of eyes with glaucoma, measured by mean [SE] differences in blood flux index (0.06 [0.01]; 95% CI, 0.04-0.09; P < .001) and vessel area density (0.04% [0.02%]; 95% CI, 0.02%-0.08%; P = .003) but not in RNFL thickness (3.4 [4.7] μm; 95% CI, -6.2 to 12.9 µm; P = .48). Strong correlations were found between the blood flux index and VF mean deviation (Spearman ρ = 0.44; P = .045) and RNFL thickness (Spearman ρ = 0.65; P = .001) in the normal hemisphere of the eye with glaucoma. Reduced RNFL microcirculation was detected in the normal hemisphere of eyes with glaucoma, with strong correspondence with VF loss and RNFL thinning. Although the results suggest that vascular dysfunction precedes structural changes seen in glaucoma, longitudinal studies would be needed to confirm this finding.

WATER BOILER REACTOR

DOEpatents

King, L.D.P.

1960-11-22

As its name implies, this reactor utilizes an aqueous solution of a fissionable element salt, and is also conventional in that it contains a heat exchanger cooling coil immersed in the fuel. Its novelty lies in the utilization of a cylindrical reactor vessel to provide a critical region having a large and constant interface with a supernatant vapor region, and the use of a hollow sleeve coolant member suspended from the cover assembly in coaxial relation with the reactor vessel. Cool water is circulated inside this hollow coolant member, and a gap between its outer wall and the reactor vessel is used to carry off radiolytic gases for recombination in an external catalyst chamber. The central passage of the coolant member defines a reflux condenser passage into which the externally recombined gases are returned and condensed. The large and constant interface between fuel solution and vapor region prevents the formation of large bubbles and minimizes the amount of fuel salt carried off by water vapor, thus making possible higher flux densities, specific powers and power densities.

Density Measurement of Compact Toroid with Mach-Zehnder Interferometer

NASA Astrophysics Data System (ADS)

Laufman-Wollitzer, Lauren; Endrizzi, Doug; Brookhart, Matt; Flanagan, Ken; Forest, Cary

2016-10-01

Utilizing a magnetized coaxial plasma gun (MCPG) built by Tri Alpha Energy, a dense compact toroid (CT) is created and injected at high speed into the Wisconsin Plasma Astrophysics Laboratory (WiPAL) vessel. A modified Mach-Zehnder interferometer from the Line-Tied Reconnection Experiment (LTRX) provides an absolute measurement of electron density. The interferometer is located such that the beam intersects the plasma across the diameter of the MCPG drift region before the CT enters the vessel. This placement ensures that the measurement is taken before the CT expand. Results presented will be used to further analyze characteristics of the CT. Funding provided by DoE, NSF, and WISE Summer Research.

Long-term acclimatization of hydraulic properties, xylem conduit size, wall strength and cavitation resistance in Phaseolus vulgaris in response to different environmental effects.

PubMed

Holste, Ellen K; Jerke, Megan J; Matzner, Steven L

2006-05-01

Phaseolus vulgaris grown under various environmental conditions was used to assess long-term acclimatization of xylem structural characteristics and hydraulic properties. Conduit diameter tended to be reduced and 'wood' density (of 'woody' stems) increased under low moisture ('dry'), increased soil porosity ('porous soil') and low phosphorus ('low P') treatments. Dry and low P had the largest percentage of small vessels. Dry, low light ('shade') and porous soil treatments decreased P50 (50% loss in conductivity) by 0.15-0.25 MPa (greater cavitation resistance) compared with 'controls'. By contrast, low P increased P50 by 0.30 MPa (less cavitation resistance) compared with porous soil (the control for low P). Changes in cavitation resistance were independent of conduit diameter. By contrast, changes in cavitation resistance were correlated with wood density for the control, dry and porous soil treatments, but did not appear to be a function of wood density for the shade and low P treatments. In a separate experiment comparing control and porous soil plants, stem hydraulic conductivity (kh), specific conductivity (ks), leaf specific conductivity (LSC), total pot water loss, plant biomass and leaf area were all greater for control plants compared to porous soil plants. Porous soil plants, however, demonstrated higher midday stomatal conductance to water vapour (gs), apparently because they experienced proportionally less midday xylem cavitation.

Keratoacanthoma versus invasive squamous cell carcinoma: a comparison of dermatoscopic vascular features in 510 cases.

PubMed

Pyne, John H; Windrum, Graham; Sapkota, Devendra; Wong, Jian Cheng

2014-07-01

Keratoacanthoma (KA) and invasive squamous cell carcinoma (SCC) are keratinocytic tumors displaying vascular features, imaged using dermatoscopy. Compare the dermatoscopy vascular features of KA to SCC. This prospective study examined consecutive cases of 100 KA and 410 invasive SCC in a single private practice in Sydney, Australia. Vascular features were recorded in vivo direct from patients using a non-polarized Delta 20 Heine dermatoscope. These vascular features were: linear, branching, serpentine, hairpin, glomerular and dot vessels, the presence or absence of large diameter tumor vessels, vessel presence in central verses peripheral tumor areas and tumor pink areas in different proportions. Following full excision, all cases were submitted for histopathologic diagnosis. Branching vessels were the only vessel morphology that varied, with a significant incidence in KA (25.0%), compared to SCC (10.7%), P < 0.01. Large vessels were identified in 20.0% of KA, compared to 12.4% in SCC, P = 0.05. No vessels were observed in the central tumor areas in 43.4 % of KA compared to 58.0% of SCC, P = 0.01. Other data comparing the central versus peripheral tumor areas for vessels present did not reveal any distinctive associations. There were no significant differences between KA and SCC when reviewing the selected proportions of pink within the tumor. The vascular features may be confounded by tumor depth in KA. Polarized dermatoscopy may not produce the same findings. This study found branching vessels to have a higher incidence in KA compared to invasive SCC. Although not statistically significant, large diameter vessels were also more frequent in KA. Proportions of pink within the tumor or central verses peripheral tumor vessel distribution were not useful diagnostic features separating KA from SCC using dermatoscopy.

Midplane neutral density profiles in the National Spherical Torus Experiment

DOE PAGES

Stotler, D. P.; Scotti, F.; Bell, R. E.; ...

2015-08-13

Atomic and molecular density data in the outer midplane of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] are inferred from tangential camera data via a forward modeling procedure using the DEGAS 2 Monte Carlo neutral transport code. The observed Balmer-β light emission data from 17 shots during the 2010 NSTX campaign display no obvious trends with discharge parameters such as the divertor Balmer-α emission level or edge deuterium ion density. Simulations of 12 time slices in 7 of these discharges produce molecular densities near the vacuum vessel wall of 2–8 × 10 17 m –3 and atomic densitiesmore » ranging from 1 to 7 ×10 16 m –3; neither has a clear correlation with other parameters. Validation of the technique, begun in an earlier publication, is continued with an assessment of the sensitivity of the simulated camera image and neutral densities to uncertainties in the data input to the model. The simulated camera image is sensitive to the plasma profiles and virtually nothing else. The neutral densities at the vessel wall depend most strongly on the spatial distribution of the source; simulations with a localized neutral source yield densities within a factor of two of the baseline, uniform source, case. Furthermore, the uncertainties in the neutral densities associated with other model inputs and assumptions are ≤ 50%.« less

Shipping container for fissile material

DOEpatents

Crowder, H.E.

1984-12-17

The present invention is directed to a shipping container for the interstate transportation of enriched uranium materials. The shipping container is comprised of a rigid, high-strength, cylindrical-shaped outer vessel lined with thermal insulation. Disposed inside the thermal insulation and spaced apart from the inner walls of the outer vessel is a rigid, high-strength, cylindrical inner vessel impervious to liquid and gaseous substances and having the inner surfaces coated with a layer of cadmium to prevent nuclear criticality. The cadmium is, in turn, lined with a protective shield of high-density urethane for corrosion and wear protection. 2 figs.

The Role of Retinal Vascular Density as a Screening Tool for Ageing and Stroke.

PubMed

Sprödhuber, Andrea; Wolz, Johannes; Budai, Attila; Laumeier, Inga; Audebert, Heinrich J; Michelson, Georg

2018-06-06

To measure the density of retinal vessels from digitized fundus photographs in patients with recent stroke and age-matched controls. To investigate whether the parameter retinal vascular density (RVD) served as a quantitative marker for cerebrovascular events. Digitized fundus photographs of n = 158 subjects with stroke or transient ischemic attack within 1 year at the time of examination and n = 1,250 age-matched controls without any remarkable medical history were examined. Sex, hypertension, and diabetes were considered to be cofactors. Measurement of RVD was performed with a computer-aided image-analyzing program by segmenting automatically all visible retinal vessels and measuring areas of vessels in distinct circles around the optic disk. In controls RVD dwindles with increasing distance from the optic disk. RVD decreased significantly with age (p = 0.000). Stroke patients showed significantly lower values of RVD of -15% in comparison to age-matched controls. In old subjects, stroke in combination with hypertension is associated with a significant decreased RVD, and in middle-aged subjects diabetes and stroke are associated with a significant decreased RVD (p = 0.01). Age and stroke are significant risk factors for decreased RVD. Diabetes and arterial hypertension are additional significant risk factors in patients with stroke with respect to RVD. © 2018 S. Karger AG, Basel.

Harbour porpoises react to low levels of high frequency vessel noise

PubMed Central

Dyndo, Monika; Wiśniewska, Danuta Maria; Rojano-Doñate, Laia; Madsen, Peter Teglberg

2015-01-01

Cetaceans rely critically on sound for navigation, foraging and communication and are therefore potentially affected by increasing noise levels from human activities at sea. Shipping is the main contributor of anthropogenic noise underwater, but studies of shipping noise effects have primarily considered baleen whales due to their good hearing at low frequencies, where ships produce most noise power. Conversely, the possible effects of vessel noise on small toothed whales have been largely ignored due to their poor low-frequency hearing. Prompted by recent findings of energy at medium- to high-frequencies in vessel noise, we conducted an exposure study where the behaviour of four porpoises (Phocoena phocoena) in a net-pen was logged while they were exposed to 133 vessel passages. Using a multivariate generalised linear mixed-effects model, we show that low levels of high frequency components in vessel noise elicit strong, stereotyped behavioural responses in porpoises. Such low levels will routinely be experienced by porpoises in the wild at ranges of more than 1000 meters from vessels, suggesting that vessel noise is a, so far, largely overlooked, but substantial source of disturbance in shallow water areas with high densities of both porpoises and vessels. PMID:26095689

Compromised regulation of tissue perfusion and arteriogenesis limit, in an AT1R-independent fashion, recovery of ischemic tissue in Cx40−/− mice

PubMed Central

Fang, Jennifer S.; Angelov, Stoyan N.; Simon, Alexander M.

2013-01-01

Recently, we reported that recovery of tissue perfusion in the ischemic hindlimb was reduced, inflammatory response increased, and survival of distal limb tissue compromised in connexin 40 (Cx40)-deficient (Cx40−/−) mice. Here we evaluate whether genotype-specific differences in tissue perfusion, native vascular density, arteriogenesis, blood pressure, and chronic ANG II type 1 receptor (AT1R) activation contribute to poor recovery of ischemic hindlimb tissue in Cx40−/− mice. Hindlimb ischemia was induced in wild-type (WT), Cx40−/−, and losartan-treated Cx40−/− mice by using surgical procedures that either maintained (mild surgery) or compromised (severe surgery) perfusion of major collateral vessels supplying the distal limb. Pre- and postsurgical hindlimb perfusion was evaluated, and tissue survival, microvascular density, and macrophage infiltration were documented during recovery. Hindlimb perfusion was compromised in presurgical Cx40−/− versus WT mice despite comparable native microvascular density. Hindlimb perfusion 24 h postsurgery in Cx40−/− and WT mice was comparable after mild surgery (collateral vessels maintained), but compromised arteriogenesis in Cx40−/− animals nevertheless limited subsequent recovery of tissue perfusion and compromised tissue survival. Prolonged pre- and postsurgical treatment of Cx40−/− mice with losartan (an AT1R antagonist) normalized blood pressure but did not improve tissue perfusion or survival, despite reduced macrophage infiltration. Thus it appears Cx40 is necessary for normal tissue perfusion and for recovery of perfusion, arteriogenesis, and tissue survival in the ischemic hindlimb. Our data suggest that Cx40−/− mice are at significantly greater risk for poor recovery from ischemic insult due to compromised regulation of tissue perfusion, vascular remodeling, and prolonged inflammatory response. PMID:23292716

"Deep-media culture condition" promoted lumen formation of endothelial cells within engineered three-dimensional tissues in vitro.

PubMed

Sekiya, Sachiko; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

2011-03-01

In the field of tissue engineering, the induction of microvessels into tissues is an important task because of the need to overcome diffusion limitations of oxygen and nutrients within tissues. Powerful methods to create vessels in engineered tissues are needed for creating real living tissues. In this study, we utilized three-dimensional (3D) highly cell dense tissues fabricated by cell sheet technology. The 3D tissue constructs are close to living-cell dense tissue in vivo. Additionally, creating an endothelial cell (EC) network within tissues promoted neovascularization promptly within the tissue after transplantation in vivo. Compared to the conditions in vivo, however, common in vitro cell culture conditions provide a poor environment for creating lumens within 3D tissue constructs. Therefore, for determining adequate conditions for vascularizing engineered tissue in vitro, our 3D tissue constructs were cultured under a "deep-media culture conditions." Compared to the control conditions, the morphology of ECs showed a visibly strained cytoskeleton, and the density of lumen formation within tissues increased under hydrostatic pressure conditions. Moreover, the increasing expression of vascular endothelial cadherin in the lumens suggested that the vessels were stabilized in the stimulated tissues compared with the control. These findings suggested that deep-media culture conditions improved lumen formation in engineered tissues in vitro.

Background noise in piezoresistive, electret condenser, and ceramic microphones.

PubMed

Zuckerwar, Allan J; Kuhn, Theodore R; Serbyn, Roman M

2003-06-01

Background noise studies have been extended from air condenser microphones to piezoresistive, electret condenser, and ceramic microphones. Theoretical models of the respective noise sources within each microphone are developed and are used to derive analytical expressions for the noise power spectral density for each type. Several additional noise sources for the piezoresistive and electret microphones, beyond what had previously been considered, were applied to the models and were found to contribute significantly to the total noise power spectral density. Experimental background noise measurements were taken using an upgraded acoustic isolation vessel and data acquisition system, and the results were compared to the theoretically obtained expressions. The models were found to yield power spectral densities consistent with the experimental results. The measurements reveal that the 1/f noise coefficient is strongly correlated with the diaphragm damping resistance, irrespective of the detection technology, i.e., air condenser, piezoresistive, etc. This conclusion has profound implications upon the expected 1/f noise component of micromachined (MEMS) microphones.

Circulating fibrocytes stabilize blood vessels during angiogenesis in a paracrine manner.

PubMed

Li, Jinqing; Tan, Hong; Wang, Xiaolin; Li, Yuejun; Samuelson, Lisa; Li, Xueyong; Cui, Caibin; Gerber, David A

2014-02-01

Accumulating evidence supports that circulating fibrocytes play important roles in angiogenesis. However, the specific role of fibrocytes in angiogenesis and the underlying mechanisms remain unclear. In this study, we found that fibrocytes stabilized newly formed blood vessels in a mouse wound-healing model by inhibiting angiogenesis during the proliferative phase and inhibiting blood vessel regression during the remodeling phase. Fibrocytes also inhibited angiogenesis in a Matrigel mouse model. In vitro study showed that fibrocytes inhibited both the apoptosis and proliferation of vascular endothelial cells (VECs) in a permeable support (Transwell) co-culture system. In a three-dimensional collagen gel, fibrocytes stabilized the VEC tubes by decreasing VEC tube density on stimulation with growth factors and preventing VEC tube regression on withdrawal of growth factors. Further mechanistic investigation revealed that fibrocytes expressed many prosurvival factors that are responsible for the prosurvival effect of fibrocytes on VECs and blood vessels. Fibrocytes also expressed angiogenesis inhibitors, including thrombospondin-1 (THBS1). THBS1 knockdown partially blocked the fibrocyte-induced inhibition of VEC proliferation in the Transwell co-culture system and recovered the fibrocyte-induced decrease of VEC tube density in collagen gel. Purified fibrocytes transfected with THBS1 siRNA partially recovered the fibrocyte-induced inhibition of angiogenesis in both the wound-healing and Matrigel models. In conclusion, our findings reveal that fibrocytes stabilize blood vessels via prosurvival factors and anti-angiogenic factors, including THBS1. Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Computed tomography in pulmonary sarcoidosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynch, D.A.; Webb, W.R.; Gamsu, G.

1989-05-01

We studied the high resolution CT (HRCT) scans of 15 patients with biopsy-proven sarcoidosis and correlated the findings with pulmonary function tests (12 patients), 67Ga scans (10 patients), bronchoalveolar lavage (five patients), recent transbronchial biopsy (six patients), and recent open lung biopsy (three patients). The HRCT features included small nodules, thickened interlobular septa, patchy focal increase in lung density, honeycombing, and central conglomeration of vessels and bronchi. Active alveolitis was present by gallium scanning criteria in 5 of 10 cases. By bronchoalveolar lavage criteria, activity was present in three of five cases. Patchy increase in density may correlate with activemore » alveolitis as seen on /sup 67/Ga scanning. High resolution CT was better than chest X-radiography for demonstration of patchy increase in density and for distinguishing nodules from septal thickening. Both nodules and patchy density were partly reversible following therapy. Nodular densities seen on CT correlated with the presence of granulomata on histology. Resting pulmonary function tests correlated poorly with presence and extent of lung disease on HRCT. The presence on HRCT of focal fine nodules, patchy focal increase in lung density, and central crowding of bronchi and vessels should suggest the diagnosis of sarcoidosis. In some patients, HRCT can identify unsuspected parenchymal lung disease and document the reversible components of sarcoid lung disease.« less

Noninvasive Imaging of Retinal Morphology and Microvasculature in Obese Mice Using Optical Coherence Tomography and Optical Microangiography

PubMed Central

Zhi, Zhongwei; Chao, Jennifer R.; Wietecha, Tomasz; Hudkins, Kelly L.; Alpers, Charles E.; Wang, Ruikang K.

2014-01-01

Purpose. To evaluate early diabetes-induced changes in retinal thickness and microvasculature in a type 2 diabetic mouse model by using optical coherence tomography (OCT)/optical microangiography (OMAG). Methods. Twenty-two-week-old obese (OB) BTBR mice (n = 10) and wild-type (WT) control mice (n = 10) were imaged. Three-dimensional (3D) data volumes were captured with spectral domain OCT using an ultrahigh-sensitive OMAG scanning protocol for 3D volumetric angiography of the retina and dense A-scan protocol for measurement of the total retinal blood flow (RBF) rate. The thicknesses of the nerve fiber layer (NFL) and that of the NFL to the inner plexiform layer (IPL) were measured and compared between OB and WT mice. The linear capillary densities within intermediate and deep capillary layers were determined by the number of capillaries crossing a 500-μm line. The RBF rate was evaluated using an en face Doppler approach. These quantitative measurements were compared between OB and WT mice. Results. The retinal thickness of the NFL to IPL was significantly reduced in OB mice (P < 0.01) compared to that in WT mice, whereas the NFL thickness between the two was unchanged. 3D depth-resolved OMAG angiography revealed the first in vivo 3D model of mouse retinal microcirculation. Although no obvious differences in capillary vessel densities of the intermediate and deep capillary layers were detected between normal and OB mice, the total RBF rate was significantly lower (P < 0.05) in OB mice than in WT mice. Conclusions. We conclude that OB BTBR mice have significantly reduced NFL–IPL thicknesses and total RBF rates compared with those of WT mice, as imaged by OCT/OMAG. OMAG provides an unprecedented capability for high-resolution depth-resolved imaging of mouse retinal vessels and blood flow that may play a pivotal role in providing a noninvasive method for detecting early microvascular changes in patients with diabetic retinopathy. PMID:24458155

Lymphangiogenesis is increased in heart valve endocarditis.

PubMed

Niinimäki, Eetu; Mennander, Ari A; Paavonen, Timo; Kholová, Ivana

2016-09-15

Inflammation-associated lymphangiogenesis (IAL) has been identified as part of several acute and chronic inflammation. Sparse data exist on lymphatics during endocarditis. Fifty-two patients with surgically resected valves were included. Endocarditis was present in 18 aortic and 10 mitral valves. Controls consisted of 15 degenerative aortic and 9 degenerative mitral valves. There were 22 males with endocarditis and 17 males in controls. The mean age was 58 (SD 15) years with endocarditis vs. 62 (SD 13) years for controls. Lymphatics were detected by podoplanin antibody immunohistochemistry and morphometrical analysis was performed. The lymphatic density in endocarditis was 833 (SD 529) vessels/mm(2) (range 0-1707) as compared with 39 (SD 60) vessels/mm(2) (range 0-250) in controls (p=0.000). In endocarditis, the mean lymphatic size was 153 (SD 372) μm(2) ranging from 1 to 2034μm(2), whereas it was 30 (SD 29) μm(2), with maximum 90μm(2) and minimum 2μm(2) in controls (p=0.000). IAL is increased in valves with endocarditis as compared with controls. Lymphatics in heart valves may provide a novel means for treatment strategies against endocarditis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

By Different Cellular Mechanisms, Lymphatic Vessels Sprout by Endothelial Cell Recruitment Whereas Blood Vessels Grow by Vascular Expansion

NASA Technical Reports Server (NTRS)

Parsons-Wingerter, Patricia; McKay, Terri L.; Leontiev, Dmitry; Condrich, Terence K.; DiCorleto, Paul E.

2005-01-01

The development of effective vascular therapies requires the understanding of all modes of vessel formation contributing to vasculogenesis, angiogenesis (here termed hemangiogenesis) and lymphangiogenesis. We show that lymphangiogenesis proceeds by blind-ended vessel sprouting via recruitment of isolated endothelial progenitor cells to the tips of growing vessels, whereas hemangiogenesis occurs by non-sprouting vessel expansion from the capillary network, during middevelopment in the quail chorioallantoic membrane (CAM). Blood vessels expanded out of capillaries that displayed transient expression of alpha smooth muscle actin (alphaSMA), accompanied by mural recruitment of migratory progenitor cells expressing SMA. Lymphatics and blood vessels were identified by confocal/fluorescence microscopy of vascular endothelial growth factor (VEGF) receptors VEGFR-1 and VEGFR-2, alphaSMA (expressed on CAM blood vessels but not on lymphatics), homeobox transcription factor Prox-1 (specific to CAM lymphatic endothelium), and the quail hematopoetic/vascular marker, QH-1. Expression of VEGFR-1 was highly restricted to blood vessels (primarily capillaries). VEGFR-2 was expressed intensely in isolated hematopoietic cells, lymphatic vessels and moderately in blood vessels. Prox-1 was absent from endothelial progenitor cells prior to lymphatic recruitment. Although vascular endothelial growth factor-165 (VEGF(sub 165)) is a key regulator of numerous cellular processes in hemangiogenesis and vasculogenesis, the role of VEGF(sub 165) in lymphangiogenesis is less clear. Exogenous VEGF(sub 165) increased blood vessel density without changing endogenous modes of vascular/lymphatic vessel formation or marker expression patterns. However, VEGF(sub 165) did increase the frequency of blood vascular anastomoses and strongly induced the antimaturational dissociation of lymphatics from blood vessels, with frequent formation of homogeneous lymphatic networks.

The importance of matched poloidal spectra to error field correction in DIII-D

DOE PAGES

Paz-Soldan, Carlos; Lanctot, Matthew J.; Logan, Nikolas C.; ...

2014-07-09

Optimal error field correction (EFC) is thought to be achieved when coupling to the least-stable "dominant" mode of the plasma is nulled at each toroidal mode number ( n). The limit of this picture is tested in the DIII-D tokamak by applying superpositions of in- and ex-vessel coil set n = 1 fields calculated to be fully orthogonal to the n = 1 dominant mode. In co-rotating H-mode and low-density Ohmic scenarios the plasma is found to be respectively 7x and 20x less sensitive to the orthogonal field as compared to the in-vessel coil set field. For the scenarios investigated,more » any geometry of EFC coil can thus recover a strong majority of the detrimental effect introduced by the n = 1 error field. Furthermore, despite low sensitivity to the orthogonal field, its optimization in H-mode is shown to be consistent with minimizing the neoclassical toroidal viscosity torque and not the higher-order n = 1 mode coupling.« less

Nickel-hydrogen bipolar battery systems

NASA Technical Reports Server (NTRS)

Thaller, L. H.

1982-01-01

Nickel-hydrogen cells are currently being manufactured on a semi-experimental basis. Rechargeable nickel-hydrogen systems are described that more closely resemble a fuel cell system than a traditional nickel-cadmium battery pack. This has been stimulated by the currently emerging requirements related to large manned and unmanned low earth orbit applications. The resultant nickel-hydrogen battery system should have a number of features that would lead to improved reliability, reduced costs as well as superior energy density and cycle lives as compared to battery systems constructed from the current state-of-the-art nickel-hydrogen individual pressure vessel cells.

Intake of melatonin is associated with amelioration of physiological changes, both metabolic and morphological pathologies associated with obesity: an animal model.

PubMed

Hussein, Mahmoud R; Ahmed, Omyma G; Hassan, Asmaa F; Ahmed, Marwa A

2007-02-01

Obesity and its associated metabolic pathologies are the most common and detrimental diseases, affecting over 50% of the adult population. Our knowledge about the protective effects of melatonin against high-fat diet (HFD)-induced obesity is still marginal. In this investigation, we hypothesized that melatonin can minimize the metabolic pathologies and morphological changes associated with obesity in animals receiving an HFD. To examine these effects, and to test our hypothesis, an animal model formed of male Boscat white rabbits was established. The animals were divided into three groups: (i) a control group fed regular diet; (ii) an obesity group fed an HFD for 12 weeks; and (iii) a treated group fed HFD for 12 weeks and then treated with melatonin for 4 weeks. The animals were killed and their serum and tissues were evaluated for: (i) lipid profile (cholesterol, triglycerides and low-density lipoprotein) and glucose; (ii) antioxidant enzyme (serum glutathione peroxidase, GSH-PX); and (iii) fatty changes (liver, kidney and blood vessels). Compared with the control group, intake of HFD (obesity group) was associated with: (i) a statistically significant increase in blood pressure, heart rate, sympathetic nerve activity, body weight, food consumption, serum lipids, blood glucose levels and atherogenic index; (ii) decreased level of GSH-PX and high-density lipoprotein (HDL); and (iii) fatty changes in the liver and kidney as well as atheromatous changes in the blood vessels. Compared with the obesity group, intake of melatonin (treated group) was associated with: (i) a statistically significant decrease in blood pressure, heart rate, sympathetic nerve activity, body weight, food consumption, serum lipids, blood glucose levels and atherogenic index; (ii) increased level of GSH-PX and HDL; and (iii) disappearance of fatty changes in the liver and kidney as well as atheromatous changes in the blood vessels. The administration of melatonin reduced the metabolic pathologies associated with the intake of HFD, suggesting a protective role. Although the underlying mechanisms are unclear, they may include its antioxidant and receptor-mediated effects. The clinical ramifications of these effects await further investigations.

Effects of Angiopoietin-1 on Hemorrhagic Transformation and Cerebral Edema after Tissue Plasminogen Activator Treatment for Ischemic Stroke in Rats

PubMed Central

Kawamura, Kunio; Takahashi, Tetsuya; Kanazawa, Masato; Igarashi, Hironaka; Nakada, Tsutomu; Nishizawa, Masatoyo; Shimohata, Takayoshi

2014-01-01

An angiogenesis factor, angiopoietin-1 (Ang1), is associated with the blood-brain barrier (BBB) disruption after focal cerebral ischemia. However, whether hemorrhagic transformation and cerebral edema after tissue plasminogen activator (tPA) treatment are related to the decrease in Ang1 expression in the BBB remains unknown. We hypothesized that administering Ang1 might attenuate hemorrhagic transformation and cerebral edema after tPA treatment by stabilizing blood vessels and inhibiting hyperpermeability. Sprague-Dawley rats subjected to thromboembolic focal cerebral ischemia were assigned to a permanent ischemia group (permanent middle cerebral artery occlusion; PMCAO) and groups treated with tPA at 1 h or 4 h after ischemia. Endogenous Ang1 expression was observed in pericytes, astrocytes, and neuronal cells. Western blot analyses revealed that Ang1 expression levels on the ischemic side of the cerebral cortex were decreased in the tPA-1h, tPA-4h, and PMCAO groups as compared to those in the control group (P = 0.014, 0.003, and 0.014, respectively). Ang1-positive vessel densities in the tPA-4h and PMCAO groups were less than that in the control group (p = 0.002 and <0.001, respectively) as well as that in the tPA-1h group (p = 0.047 and 0.005, respectively). These results suggest that Ang1-positive vessel density was maintained when tPA was administered within the therapeutic time window (1 h), while it was decreased when tPA treatment was given after the therapeutic time window (4 h). Administering Ang1 fused with cartilage oligomeric protein (COMP) to supplement this decrease has the potential to suppress hemorrhagic transformation as measured by hemoglobin content in a whole cerebral homogenate (p = 0.007) and cerebral edema due to BBB damage (p = 0.038), as compared to administering COMP protein alone. In conclusion, Ang1 might be a promising target molecule for developing vasoprotective therapies for controlling hemorrhagic transformation and cerebral edema after tPA treatment. PMID:24896569

SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY REVEALS INTERNAL LIMITING MEMBRANE PEELING ALTERS DEEP RETINAL VASCULATURE.

PubMed

Michalewska, Zofia; Nawrocki, Jerzy

2018-04-30

To describe morphology of retinal and choroidal vessels in swept-source optical coherence tomography angiography before and after vitrectomy with the temporal inverted internal limiting membrane (ILM) flap technique for full-thickness macular holes. Prospective, observational study of 36 eyes of 33 patients with full-thickness macular holes swept-source optical coherence tomography angiography was performed in patients before and 1 month after vitrectomy. Vitrectomy with the temporal inverted ILM flap technique was performed. In this method, ILM is peeled only at one side of the fovea. An ILM flap is created to cover the macular hole. Comparison of retina vasculature in the areas of ILM peeling vs. no ILM peeling at 1 and 3 months after successful vitrectomy was performed. The study demonstrated lower density of vessels in the deep retinal plexus in the area where ILM was peeled as compared to the rest of the fovea. Visual acuity and central retinal thickness 1 month after surgery correlates with fovea avascular zone diameter in deep retinal layers at the same time point (P = 0.001). This study confirmed that ILM peeling might alter blood flow in deep retinal vessels below the peeling area in the early postoperative period. The area of the fovea avascular zone corresponds to functional results at the same time point.

New Developments in Nickel-Hydrogen Dependent Pressure Vessel (DPV) Cell and Battery Design

NASA Technical Reports Server (NTRS)

Caldwell, Dwight B.; Fox, Chris L.; Miller, Lee E.

1997-01-01

THe Dependent Pressure Vessel (DPV) Nickel-Hydrogen (NiH2) design is being developed as an advanced battery for military and commercial, aerospace and terrestrial applications. The DPV cell design offers high specific energy and energy density as well as reduced cost, while retaining the established Individual Pressure Vessel (IPV) technology flight heritage and database. This advanced DPV design also offers a more efficient mechanical, electrical and thermal cell and battery configuration and a reduced part count. The DPV battery design promotes compact, minimum volume packaging and weight efficiency, and delivers cost and weight savings with minimal design risk.

The Lymphatic Phenotype of Lung Allografts in Patients With Bronchiolitis Obliterans Syndrome and Restrictive Allograft Syndrome.

PubMed

Traxler, Denise; Schweiger, Thomas; Schwarz, Stefan; Schuster, Magdalena Maria; Jaksch, Peter; Lang, Gyoergy; Birner, Peter; Klepetko, Walter; Ankersmit, Hendrik Jan; Hoetzenecker, Konrad

2017-02-01

Chronic lung allograft dysfunction (CLAD), presenting as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS) is the major limiting factor of long-term survival in lung transplantation. Its pathogenesis is still obscure. In BOS, persistent alloimmune injury and chronic airway inflammation are suggested. One of the main tasks of the lymphatic vessel (LV) system is the promotion of immune cell trafficking. The formation of new LVs has been shown to trigger chronic allograft rejection in kidney transplants. We therefore sought to address the role of lymphangiogenesis in CLAD. Formalin-fixed paraffin-embedded tissue samples of 22 patients receiving a lung retransplantation due to BOS or RAS were collected. Lymphatic vessel density (LVD) was determined by immunohistochemical staining for podoplanin. Lung tissue obtained from 13 non-CLAD patients served as control. The impact of LVD on graft survival was assessed. Lymphatic vessel density in CLAD patients did not differ from those in control subjects (median number of LVs per bronchiole: 4.75 (BOS), 6.47 (RAS), 4.25 (control), P = 0.97). Moreover, the number of LVs was not associated with regions of cellular infiltrates (median number of LVs per bronchiole: with infiltrates, 5.00 (BOS), 9.00 (RAS), 4.00 (control), P = 0.62; without infiltrates, 4.5 (BOS), 0.00 (RAS), 4.56 (control), P = 0.74). Lymphatic vessel density did not impact the time to development of BOS or RAS in lung transplantation (low vs high LVD: 38.5 vs 86.0 months, P = 0.15 [BOS]; 60.5 vs 69.5 months, P = 0.80 [RAS]). Unlike chronic organ failure in kidney transplantation, lymphangiogenesis is not altered in CLAD patients. Our findings highlight unique immunological processes leading to BOS and RAS.

Electrical swing adsorption gas storage and delivery system

DOEpatents

Judkins, Roddie R.; Burchell, Timothy D.

1999-01-01

Systems and methods for electrical swing natural gas adsorption are described. An apparatus includes a pressure vessel; an electrically conductive gas adsorptive material located within the pressure vessel; and an electric power supply electrically connected to said adsorptive material. The adsorptive material can be a carbon fiber composite molecular sieve (CFCMS). The systems and methods provide advantages in that both a high energy density and a high ratio of delivered to stored gas are provided.

Corpus callosum vasculature predicts white matter microstructure abnormalities following pediatric mild traumatic brain injury.

PubMed

Wendel, Kara M; Lee, Jeong Bin; Affeldt, Bethann; Hamer, Mary; Harahap-Carrillo, Indira S; Pardo, Andrea C; Obenaus, Andre

2018-05-09

Emerging data suggest that pediatric traumatic brain injury (TBI) is associated with impaired developmental plasticity and poorer neuropsychological outcomes than adults with similar head injuries. Unlike adult mild TBI (mTBI), the effects of mTBI on white matter (WM) microstructure and vascular supply are not well-understood in the pediatric population. The cerebral vasculature plays an important role providing necessary nutrients and removing waste. To address this critical element, we examined the microstructure of the corpus callosum (CC) following pediatric mTBI using diffusion tensor imaging (DTI), and investigated myelin, oligodendrocytes, and vasculature of WM with immunohistochemistry. We hypothesized that pediatric mTBI leads to abnormal WM microstructure and impacts the vasculature within the CC, and that these alterations to WM vasculature contribute to the long-term altered microstructure. We induced a closed head injury mTBI at postnatal day 14, then at 4, 14, and 60 days post injury (DPI) mice were sacrificed for analysis. We observed persistent changes in apparent diffusion coefficient (ADC) within the ipsilateral CC following mTBI, indicating microstructural changes, but surprisingly changes in myelin and oligodendrocyte densities were minimal. However, vasculature features of the ipsilateral CC such as vessel density, length, and number of junctions were persistently altered following mTBI. Correlative analysis showed a strong inverse relationship between ADC and vessel density at 60 DPI, suggesting increased vessel density following mTBI may restrict WM diffusion characteristics. Our findings suggest that WM vasculature contributes to the long-term microstructural changes within the ipsilateral CC following mTBI.

Evolution of US maize (Zea mays L.) root architectural and anatomical phenes over the past 100 years corresponds to increased tolerance of nitrogen stress

PubMed Central

York, Larry M.; Galindo-Castañeda, Tania; Schussler, Jeffrey R.; Lynch, Jonathan P.

2015-01-01

Increasing the nitrogen use efficiency of maize is an important goal for food security and agricultural sustainability. In the past 100 years, maize breeding has focused on yield and above-ground phenes. Over this period, maize cultivation has changed from low fertilizer inputs and low population densities to intensive fertilization and dense populations. The authors hypothesized that through indirect selection the maize root system has evolved phenotypes suited to more intense competition for nitrogen. Sixteen maize varieties representing commercially successful lines over the past century were planted at two nitrogen levels and three planting densities. Root systems of the most recent material were 7 º more shallow, had one less nodal root per whorl, had double the distance from nodal root emergence to lateral branching, and had 14% more metaxylem vessels, but total mextaxylem vessel area remained unchanged because individual metaxylem vessels had 12% less area. Plasticity was also observed in cortical phenes such as aerenchyma, which increased at greater population densities. Simulation modelling with SimRoot demonstrated that even these relatively small changes in root architecture and anatomy could increase maize shoot growth by 16% in a high density and high nitrogen environment. The authors concluded that evolution of maize root phenotypes over the past century is consistent with increasing nitrogen use efficiency. Introgression of more contrasting root phene states into the germplasm of elite maize and determination of the functional utility of these phene states in multiple agronomic conditions could contribute to future yield gains. PMID:25795737

Histomorphometric Analysis of Angiogenesis using CD31 Immunomarker and Mast Cell Density in Oral Premalignant and Malignant Lesions: A Pilot Study.

PubMed

Jyothsna, M; Rammanohar, M; Kumar, Kiran

2017-01-01

Mast cells have been implicated in promoting angiogenesis in malignant tumors of lung, oesophagus and breast, but there are few studies on Oral Squamous Cell Carcinomas (OSCC). Most oral squamous cell carcinomas arise from pre-existing precancerous lesions exhibiting epithelial dysplasia. The present pilot study attempts to compare Mast Cell Density (MCD), Microvessel Density (MVD), Microvessel Area (MVA) histomorphometrically between normal buccal mucosa, severe epithelial dysplasia and OSCC and to correlate the role of mast cells and angiogenesis in tumor progression. The retrospective study was conducted on eight cases of OSCC, eight cases of severe epithelial dysplasia and five cases of normal buccal mucosa. Immunohistochemical staining with anti CD-31, to demonstrate angiogenesis and toluidine blue staining for mast cells were employed. MVA, MVD and MCD were calculated using the measurement tools of the image analysis software and compared between the groups. One way ANOVA (Analysis of Variance) was used for comparing the parameter for multiple groups followed by Games Howell test. To assess the relationship between micro vessel density and mast cell density, Karl Pearson's correlation was used. MCD and MVD increased with disease progression and were statistically higher in OSCC than in severe epithelial dysplasia and normal buccal mucosa (p<0.001). MVA increased from normal to severe dysplasia and decreased from dysplasia to OSCC, may be due to revascularization of tumor tissue. A positive correlation was observed between MCD and MVD in OSCC and dysplasia, though were not statistically significant. These findings suggest that mast cells may up regulate angiogenesis in OSCC. MCD and MVD may be used as indicators for disease progression.

[Co-adaptation of enzymatic systems of cells and blood supply in smooth muscle tumors of the corpus uteri].

PubMed

Lazaarev, A F; Avbalian, A M; Bobrov, I P; Klimachev, V V; Mischenko, E V

2008-01-01

We investigated co-adaptation of enzymatic systems of cells using data on activity of NAD(Ph)-dependent enzymes and AgNOR proteins of vascular endothelium vis-a-vis angiogenesis in benign and malignant smooth muscle tumors of the corpus uteri. Overall metabolic activity (NAD-H2 diaphorase) was found to directly correlate with angiogenesis and endothelial vessel proliferation (r = 0.76 and 0.84, respectively). SDH-regulated oxidation in the main metabolic succession of a tricarbonic acid cycle depended on blood supply and endothelial vessel proliferation (r = 0.84 and 0.92, respectively; p = 0.04). A similar relationship was shown for anaerobic glycolysis of SDH (LDH content), on the one hand, and blood supply and endothelial vessel proliferation(r = 0.57 and 0.70, respectively; p = 0.02), on the other. Hence, metabolic profile varied in unaltered myometrium and tumor with variable cellular density and peculiar extracellular matrix. The highest levels of metabolic activity with NAD(Ph)-dependent enzyme co-adaptation was observed in sarcomas which were also characterized by the highest vascular density for endothelial proliferation.

Association Between Increased Vascular Density and Loss of Protective RAS in Early-stage NPDR

NASA Technical Reports Server (NTRS)

Radhakrishnan, Krishnan; Raghunandan, Sneha; Vyas, Ruchi J.; Vu, Amanda C.; Bryant, Douglas; Yaqian, Duan; Knecht, Brenda E.; Grant, Maria B.; Chalam, K. V.; Parsons-Wingerter, Patricia

2016-01-01

Our hypothesis predicts that retinal blood vessels increase in density during early-stage progression to moderate nonproliferative diabetic retinopathy (NPDR). The renin-angiotensin system (RAS) is implicated in the pathogenesis of DR and in the function of circulating angiogenic cells (CACs), a critical bone marrow-derived population that is instrumental in vascular repair.

46 CFR 42.50-15 - Coastwise load line certificates for U.S.-flag vessels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... center of ring. Winter __ (inches) (W) __ (inches) below (S). Allowance for fresh water for all... point of departure and the sea. 2. When a ship is in fresh water of unit density the appropriate load line may be submerged by the amount of the fresh water allowance shown above. Where the density is...

46 CFR 171.052 - Passenger heel requirements for pontoon vessels.

Code of Federal Regulations, 2014 CFR

2014-10-01

... on exposed or partially protected waters— (i) 10 foot-degrees with a crowding density of 5 square feet per person (2.15 persons per square meter); and (ii) 7 foot-degrees with a crowding density of 2 square feet per person (5.38 persons per square meter); and (2) For operation on protected waters— (i) 5...

46 CFR 171.052 - Passenger heel requirements for pontoon vessels.

Code of Federal Regulations, 2012 CFR

2012-10-01

... on exposed or partially protected waters— (i) 10 foot-degrees with a crowding density of 5 square feet per person (2.15 persons per square meter); and (ii) 7 foot-degrees with a crowding density of 2 square feet per person (5.38 persons per square meter); and (2) For operation on protected waters— (i) 5...

46 CFR 171.052 - Passenger heel requirements for pontoon vessels.

Code of Federal Regulations, 2011 CFR

2011-10-01

... on exposed or partially protected waters— (i) 10 foot-degrees with a crowding density of 5 square feet per person (2.15 persons per square meter); and (ii) 7 foot-degrees with a crowding density of 2 square feet per person (5.38 persons per square meter); and (2) For operation on protected waters— (i) 5...

46 CFR 171.052 - Passenger heel requirements for pontoon vessels.

Code of Federal Regulations, 2013 CFR

2013-10-01

... on exposed or partially protected waters— (i) 10 foot-degrees with a crowding density of 5 square feet per person (2.15 persons per square meter); and (ii) 7 foot-degrees with a crowding density of 2 square feet per person (5.38 persons per square meter); and (2) For operation on protected waters— (i) 5...

Orbital angiogenesis and lymphangiogenesis in thyroid eye disease: an analysis of vascular growth factors with clinical correlation

PubMed Central

Wong, Lindsay L.; Lee, Nahyoung Grace; Amarnani, Dhanesh; Choi, Catherine J.; Bielenberg, Diane R.; Freitag, Suzanne K.; D’Amore, Patricia A.; Kim, Leo A.

2017-01-01

Purpose The human orbit is an environment that is vulnerable to inflammation and edema in the setting of autoimmune thyroid disease. Our study investigated the tenet that orbital adipose tissue lacks lymphatic vessels and analyzed the clinicopathologic differences between patients with acute and chronic thyroid eye disease (TED). The underlying molecular mediators of blood and lymphatic vessel formation within the orbital fat were also evaluated. Design Retrospective cohort study Participants The study included fat specimens from 26 orbits of 15 patients with TED undergoing orbital decompression. Orbital fat specimens from patients without TED as well as cadaveric orbital fat served as controls. Methods Tissue specimens were processed as formalin-fixed paraffin-embedded sections (FFPE) or frozen cryosections for immunohistochemistry. Total RNA was extracted and analyzed via quantitative (real-time) reverse transcription polymerase chain reaction (qRT-PCR). Clinicopathological correlation was made by determining the Clinical Activity Score (CAS) of each patient with TED. Main Outcome Measures Samples were examined for vascular and lymphatic markers including podoplanin, LYVE-1, and CD31 by immunohistochemistry, as well as for mRNA levels of VEGF, VEGF receptors, SEMA-3F, NRP-1, NRP-2, podoplanin and LYVE-1 by qRT-PCR. Results Clinicopathological correlation revealed increased staining of CD31-positive blood vessels in patients with acute TED with CAS > 4, as well as rare staining of podoplanin-positive lymphatic vessels within acutely inflamed orbital fat tissue. Additionally, qRT-PCR analysis demonstrated increased expression of vascular endothelial growth factor receptor 2 (VEGFR-2) as well as VEGF signaling molecules: VEGF-A, VEGF-C, and VEGF-D. Conclusions In acute TED, compared to chronic TED and control orbital fat, there is increased blood vessel density suggesting neovascularization and rare lymphatic vessels suggestive of limited lymphangiogenesis. This pro-angiogenic and pro-lymphangiogenic microenvironment is likely due to the increased expression of VEGFR-2 and VEGF-A, VEGF-C, and VEGF-D. These findings imply that orbital edema in acute TED may be mediated, in part, by both the formation of new, immature blood vessels and the formation of lymphatic capillaries that are functionally incapable of draining interstitial fluid. PMID:27423310

3-D capacitance density imaging system

DOEpatents

Fasching, G.E.

1988-03-18

A three-dimensional capacitance density imaging of a gasified bed or the like in a containment vessel is achieved using a plurality of electrodes provided circumferentially about the bed in levels and along the bed in channels. The electrodes are individually and selectively excited electrically at each level to produce a plurality of current flux field patterns generated in the bed at each level. The current flux field patterns are suitably sensed and a density pattern of the bed at each level determined. By combining the determined density patterns at each level, a three-dimensional density image of the bed is achieved. 7 figs.

3-D capacitance density imaging of fluidized bed

DOEpatents

Fasching, George E.

1990-01-01

A three-dimensional capacitance density imaging of a gasified bed or the like in a containment vessel is achieved using a plurality of electrodes provided circumferentially about the bed in levels and along the bed in channels. The electrodes are individually and selectively excited electrically at each level to produce a plurality of current flux field patterns generated in the bed at each level. The current flux field patterns are suitably sensed and a density pattern of the bed at each level determined. By combining the determined density patterns at each level, a three-dimensional density image of the bed is achieved.

Automatic lumen and outer wall segmentation of the carotid artery using deformable three-dimensional models in MR angiography and vessel wall images.

PubMed

van 't Klooster, Ronald; de Koning, Patrick J H; Dehnavi, Reza Alizadeh; Tamsma, Jouke T; de Roos, Albert; Reiber, Johan H C; van der Geest, Rob J

2012-01-01

To develop and validate an automated segmentation technique for the detection of the lumen and outer wall boundaries in MR vessel wall studies of the common carotid artery. A new segmentation method was developed using a three-dimensional (3D) deformable vessel model requiring only one single user interaction by combining 3D MR angiography (MRA) and 2D vessel wall images. This vessel model is a 3D cylindrical Non-Uniform Rational B-Spline (NURBS) surface which can be deformed to fit the underlying image data. Image data of 45 subjects was used to validate the method by comparing manual and automatic segmentations. Vessel wall thickness and volume measurements obtained by both methods were compared. Substantial agreement was observed between manual and automatic segmentation; over 85% of the vessel wall contours were segmented successfully. The interclass correlation was 0.690 for the vessel wall thickness and 0.793 for the vessel wall volume. Compared with manual image analysis, the automated method demonstrated improved interobserver agreement and inter-scan reproducibility. Additionally, the proposed automated image analysis approach was substantially faster. This new automated method can reduce analysis time and enhance reproducibility of the quantification of vessel wall dimensions in clinical studies. Copyright © 2011 Wiley Periodicals, Inc.

A Simple Criterion to Estimate Performance of Pulse Jet Mixed Vessels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pease, Leonard F.; Bamberger, Judith A.; Mahoney, Lenna A.

Pulse jet mixed process vessels comprise a key element of the U.S. Department of Energy’s strategy to process millions of gallons of legacy nuclear waste slurries. Slurry suctioned into a pulse jet mixer (PJM) tube at the end of one pulse is pneumatically driven from the PJM toward the bottom of the vessel at the beginning of the next pulse, forming a jet. The jet front traverses the distance from nozzle outlet to the bottom of the vessel and spreads out radially. Varying numbers of PJMs are typically arranged in a ring configuration within the vessel at a selected radiusmore » and operated concurrently. Centrally directed radial flows from neighboring jets collide to create a central upwell that elevates the solids in the center of the vessel when the PJM tubes expel their contents. An essential goal of PJM operation is to elevate solids to the liquid surface to minimize stratification. Solids stratification may adversely affect throughput of the waste processing plant. Unacceptably high slurry densities at the base of the vessel may plug the pipeline through which the slurry exits the vessel. Additionally, chemical reactions required for processing may not achieve complete conversion. To avoid these conditions, a means of predicting the elevation to which the solids rise in the central upwell that can be used during vessel design remains essential. In this paper we present a simple criterion to evaluate the extent of solids elevation achieved by a turbulent upwell jet. The criterion asserts that at any location in the central upwell the local velocity must be in excess of a cutoff velocity to remain turbulent. We find that local velocities in excess of 0.6 m/s are necessary for turbulent jet flow through both Newtonian and yield stress slurries. By coupling this criterion with the free jet velocity equation relating the local velocity to elevation in the central upwell, we estimate the elevation at which turbulence fails, and consequently the elevation at which the upwell fails to further lift the slurry. Comparing this elevation to the vessel fill level predicts whether the jet flow will achieve the full vertical extent of the vessel at the center. This simple local-velocity criterion determines a minimum PJM nozzle velocity at which the full vertical extent of the central upwell in PJM vessels will be turbulent. The criterion determines a minimum because flow in regions peripheral to the central upwelling jet may not be turbulent, even when the center of the vessel in the upwell is turbulent, if the jet pulse duration is too short. The local-velocity criterion ensures only that there is sufficient wherewithal for the turbulent jet flow to drive solids to the surface in the center of the vessel in the central upwell.« less

Tumor-line specific causes of intertumor heterogeneity in blood supply in human melanoma xenografts.

PubMed

Simonsen, Trude G; Gaustad, Jon-Vidar; Leinaas, Marit N; Rofstad, Einar K

2013-01-01

The efficacy of most cancer treatments is strongly influenced by the tumor blood supply. The results of experimental studies using xenografted tumors to evaluate novel cancer treatments may therefore vary considerably depending on the blood supply of the specific tumor model being used. Mechanisms underlying intertumor heterogeneity in the blood supply of xenografted tumors derived from same tumor line are poorly understood, and were investigated here by using intravital microscopy to assess tumor blood supply and vascular morphology in human melanomas growing in dorsal window chambers in BALB/c nu/nu mice. Two melanoma lines, A-07 and R-18, were included in the study. These lines differed substantially in angiogenic profiles. Thus, when the expression of 84 angiogenesis-related genes was investigated with a quantitative PCR array, 25% of these genes showed more than a 10-fold difference in expression. Furthermore, A-07 tumors showed higher vascular density, higher vessel tortuosity, higher vessel diameters, shorter vessel segments, and more chaotic vascular architecture than R-18 tumors. Both lines showed large intertumor heterogeneity in blood supply. In the A-07 line, tumors with low microvascular density, long vessel segment, and high vessel tortuosity showed poor blood supply, whereas in the R-18 line, poor tumor blood supply was associated with low tumor arteriolar diameters. Thus, tumor-line specific causes of intertumor heterogeneity in blood supply were identified in human melanoma xenografts, and these tumor-line specific mechanisms were possibly a result of tumor-line specific angiogenic profiles. Copyright © 2012 Elsevier Inc. All rights reserved.

Buoyancy-induced mixing during wash and elution steps in expanded bed adsorption.

PubMed

Fee, C J; Liten, A D

2001-01-01

Buoyancy-induced mixing occurs during expanded bed adsorption processes when the feed stream entering the bottom of the system has a lower density than that of the fluid above it. In the absence of a headspace, mixing in the expanded bed can be modeled as a single, well-mixed vessel, with first-order dynamics. In the presence of a headspace, the system exhibits second-order dynamics for the densities typically encountered in protein chromatography, and can be modeled as two well-mixed vessels (the expanded bed and the headspace) arranged in series. In this paper, the mixing dynamics of the expanded bed are described and a mathematical model of the system is presented. Experimental measurements of density changes during the dilution of sucrose and salt solutions in a STREAMLINE 25 column are presented. These show excellent agreement with predictions using the model. A number of strategies for wash and elution in expanded mode, both in the presence and absence of headspace, are discussed.

Retinal Microvascular Network and Microcirculation Assessments in High Myopia.

PubMed

Li, Min; Yang, Ye; Jiang, Hong; Gregori, Giovanni; Roisman, Luiz; Zheng, Fang; Ke, Bilian; Qu, Dongyi; Wang, Jianhua

2017-02-01

To investigate the changes of the retinal microvascular network and microcirculation in high myopia. A cross-sectional, matched, comparative clinical study. Twenty eyes of 20 subjects with nonpathological high myopia (28 ± 5 years of age) with a refractive error of -6.31 ± 1.23 D (mean ± SD) and 20 eyes of 20 age- and sex-matched control subjects (30 ± 6 years of age) with a refractive error of -1.40 ± 1.00 D were recruited. Optical coherence tomography angiography (OCTA) was used to image the retinal microvascular network, which was later quantified by fractal analysis (box counting [D box ], representing vessel density) in both superficial and deep vascular plexuses. The Retinal Function Imager was used to image the retinal microvessel blood flow velocity (BFV). The BFV and microvascular density in the myopia group were corrected for ocular magnification using Bennett's formula. The density of both superficial and deep microvascular plexuses was significantly decreased in the myopia group in comparison to the controls (P < .05). The decrease of the microvessel density of the annular zone (0.6-2.5 mm), measured as D box , was 2.1% and 2.9% in the superficial and deep vascular plexuses, respectively. Microvessel density reached a plateau from 0.5 mm to 1.25 mm from the fovea in both groups, but that in the myopic group was about 3% lower than the control group. No significant differences were detected between the groups in retinal microvascular BFV in either arterioles or venules (P > .05). Microvascular densities in both superficial (r = -0.45, P = .047) and deep (r = -0.54, P = .01) vascular plexuses were negatively correlated with the axial lengths in the myopic eye. No correlations were observed between BFV and vessel density (P > .05). Retinal microvascular decrease was observed in the high myopia subjects, whereas the retinal microvessel BFV remained unchanged. The retinal microvascular network alteration may be attributed to ocular elongation that occurs with the progression of myopia. The novel quantitative analyses of the retinal microvasculature may help to characterize the underlying pathophysiology of myopia and enable early detection and prevention of myopic retinopathy. Copyright © 2016 Elsevier Inc. All rights reserved.

In-vessel melt retention as a severe accident management strategy for the Loviisa Nuclear Power Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kymaelaeinen, O.; Tuomisto, H.; Theofanous, T.G.

1997-02-01

The concept of lower head coolability and in-vessel retention of corium has been approved as a basic element of the severe accident management strategy for IVO`s Loviisa Plant (VVER-440) in Finland. The selected approach takes advantage of the unique features of the plant such as low power density, reactor pressure vessel without penetrations at the bottom and ice-condenser containment which ensures flooded cavity in all risk significant sequences. The thermal analyses, which are supported by experimental program, demonstrate that in Loviisa the molten corium on the lower head of the reactor vessel is coolable externally with wide margins. This papermore » summarizes the approach and the plant modifications being implemented. During the approval process some technical concerns were raised, particularly with regard to thermal loadings caused by contact of cool cavity water and hot corium with the reactor vessel. Resolution of these concerns is also discussed.« less

Head and neck cancer relapse after chemoradiotherapy correlates with CD163+ macrophages in primary tumour and CD11b+ myeloid cells in recurrences.

PubMed

Balermpas, P; Rödel, F; Liberz, R; Oppermann, J; Wagenblast, J; Ghanaati, S; Harter, P N; Mittelbronn, M; Weiss, C; Rödel, C; Fokas, E

2014-10-14

We investigated the prognostic role of tumour-associated macrophages (TAMs) in patients with head and neck squamous cell carcinoma (HNSCC) treated with definitive chemoradiotherapy (CRT). The expression of CD68+, CD163+ and CD11b+ cells was assessed using immunohistochemistry in n=106 pre-treatment tumour biopsy samples and was correlated with clinicopathological characteristics, including T-stage, N-stage, grading, tumour localisation, age and sex as well as local failure-free survival (LFFS), distant metastases-free survival (DMFS), progression-free (PFS), and overall survival (OS). Finally, TAMs expression and vessel density (CD31) were examined in n=12 available early local recurrence samples and compared with their matched primary tumours . The diagnostic images and radiotherapy plans of these 12 patients were also analysed. All local recurrences occurred in the high radiation dose region (⩾70 Gy). With a median follow-up of 40 months, OS at 2 years was 60.5%. High CD163 expression in primary tumours was associated with decreased OS (P=0.010), PFS (P=0.033), LFFS (P=0.036) and DMFS (P=0.038) in multivariate analysis. CD163 demonstrated a strong prognostic value only in human papillomavirus (p16(INK4))-negative patients. Early local recurrence specimens demonstrated a significantly increased infiltration of CD11b+ myeloid cells (P=0.0097) but decreased CD31-positive vessel density (P=0.0004) compared with their matched primary samples. Altogether, baseline CD163 expression predicts for an unfavourable clinical outcome in HNSCC after definitive CRT. Early local recurrences showed increased infiltration by CD11b+ cells. These data provide important insight on the role of TAMs in mediating response to CRT in patients with HNSCC.

Clinical study of contrast-enhanced digital mammography and the evaluation of blood and lymphatic microvessel density

PubMed Central

Cruz-Bastida, Juan P; Rosado-Méndez, Iván M; Villaseñor-Navarro, Yolanda; Pérez-Ponce, Héctor; Galván, Héctor A; Trujillo-Zamudio, Flavio E; Sánchez-Suárez, Patricia; Benítez-Bribiesca, Luis

2016-01-01

Objective: To correlate image parameters in contrast-enhanced digital mammography (CEDM) with blood and lymphatic microvessel density (MVD). Methods: 18 Breast Imaging-Reporting and Data System (BI-RADS)-4 to BI-RADS-5 patients were subjected to CEDM. Craniocaudal views were acquired, two views (low and high energy) before iodine contrast medium (CM) injection and four views (high energy) 1–5 min afterwards. Processing included registration and two subtraction modalities, traditional single-energy temporal (high-energy) and “dual-energy temporal with a matrix”, proposed to improve lesion conspicuity. Images were calibrated into iodine thickness, and iodine uptake, contrast, time–intensity and time–contrast kinetic curves were quantified. Image indicators were compared with MVD evaluated by anti-CD105 and anti-podoplanin (D2-40) immunohistochemistry. Results: 11 lesions were cancerous and 7 were benign. CEDM subtraction strongly increased conspicuity of lesions enhanced by iodine uptake. A strong correlation was observed between lymphatic vessels and blood vessels; all benign lesions had <30 blood microvessels per field, and all cancers had more than this value. MVD showed no correlation with iodine uptake, nor with contrast. The most frequent curve was early uptake followed by plateau for uptake and contrast in benign and malignant lesions. The positive-predictive value of uptake dynamics was 73% and that of contrast was 64%. Conclusion: CEDM increased lesion visibility and showed additional features compared with conventional mammography. Lack of correlation between image parameters and MVD is probably due to tumour tissue heterogeneity, mammography projective nature and/or dependence of extracellular iodine irrigation on tissue composition. Advances in knowledge: Quantitative analysis of CEDM images was performed. Image parameters and MVD showed no correlation. Probably, this is indication of the complex dependence of CM perfusion on tumour microenvironment. PMID:27376457

Antiangiogenic activity of a bevacizumab-loaded polyurethane device in animal neovascularization models.

PubMed

Ferreira, A E R; Castro, B F M; Vieira, L C; Cassali, G D; Souza, C M; Fulgêncio, G O; Ayres, E; Oréfice, R L; Jorge, R; Silva-Cunha, A; Fialho, S L

2017-03-01

To evaluate the antiangiogenic activity of bevacizumab-loaded polyurethane using two animal models of neovascularization. The percentage of blood vessels was evaluated in a chicken chorioallantoic membrane model (n=42) and in the rabbit cornea (n=24) with neovascularization induced by alkali injury. In each model, the animals were randomly divided into the groups treated with the bevacizumab-loaded polyurethane device, phosphate-buffered-saline (negative control) and bevacizumab commercial solution (positive control). Clinical examination, as well as histopathological and immunohistochemical evaluation, were performed in the rabbit eyes. Microvascular density in hot spot areas was determined in semi-thin sections of corneal tissue by hematoxylin-eosin staining and factor VIII immunohistochemistry. Immunohistochemical analysis was also performed to evaluate VEGF expression. In the evaluated models, the use of bevacizumab (Avastin ® ) and the bevacizumab-loaded polyurethane device led to similar results with regard to inhibition of neovascularization. In the chorioallantoic membrane model, the bevacizumab-loaded polyurethane device reduced angiogenesis by 50.27% when compared to the negative control group. In the rabbit model of corneal neovascularization, the mean density of vessels/field was reduced by 46.87% on analysis of factor VIII immunohistochemistry photos in the bevacizumab-loaded polyurethane device group as compared to the negative control (PBS) sections. In both models, no significant difference could be identified between the bevacizumab-loaded polyurethane device and the positive control group, leading to similar results with regard to inhibition of neovascularization. The present study shows that the bevacizumab-loaded polyurethane device may release bevacizumab and inhibit neovascularization similarly to commercial bevacizumab solution in the short-term. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effect of plasminogen activator inhibitor-1 on adipogenesis in vivo.

PubMed

Scroyen, Ilse; Jacobs, Frank; Cosemans, Leen; De Geest, Bart; Lijnen, H Roger

2009-02-01

To study the functional role of plasminogen activator inhibitor-1 (PAI-1) in obesity, the effect of its overexpression on de novo adipogenesis was evaluated in murine models in vivo. Therefore, 3T3-F442A preadipocytes expressing murine PAI-1 (mPAI-1) or control cells were injected in the back of male NUDE mice, which were fed a high-fat diet (HFD) for four weeks. De novo fat pads that formed from the PAI-1 expressing cells were larger (21 +/- 2.4 mg vs. 14 +/- 1.4 mg; p = 0.017) and showed a higher adipocyte density (373 +/- 28 mm(-2) vs. 301 +/- 12 mm(-2); p = 0.03) as compared to those formed from control cells. In a second model, male NUDE mice were injected in the tail vein with an adenoviral construct expressing mPAI-1 or with the empty vector, and three days later with 3T3-F442A cells. After four weeks of HFD, total body weight and de novo fat pad weight were comparable for both groups. Mild adipocyte hypotrophy was observed in the de novo fat pads of the PAI-1 overexpressing mice (1180 +/- 33 microm(2) vs. 1285 +/- 32 microm(2); p = 0.024), whereas the blood vessel size was significantly smaller than in controls (30 +/- 1.8 microm(2) vs. 63 +/- 3.6 microm(2); p < 0.0001). Thus, the effect of local or systemic PAI-1 (over)expression on adipocyte or blood vessel size and density of de novo formed fat pads appears to be different, and concentration-dependent. Whereas local expression resulted in larger fat pads, systemic overexpression had no effect on de novo adipogenesis, although angiogenesis appeared to be impaired.

Electrical swing adsorption gas storage and delivery system

DOEpatents

Judkins, R.R.; Burchell, T.D.

1999-06-15

Systems and methods for electrical swing natural gas adsorption are described. An apparatus includes a pressure vessel; an electrically conductive gas adsorptive material located within the pressure vessel; and an electric power supply electrically connected to said adsorptive material. The adsorptive material can be a carbon fiber composite molecular sieve (CFCMS). The systems and methods provide advantages in that both a high energy density and a high ratio of delivered to stored gas are provided. 5 figs.

Spectral-Domain Optical Coherence Tomographic Angiography in Children With Amblyopia.

PubMed

Lonngi, Marcela; Velez, Federico G; Tsui, Irena; Davila, Juan Pablo; Rahimi, Mansour; Chan, Clarissa; Sarraf, David; Demer, Joseph L; Pineles, Stacy L

2017-10-01

Amblyopia is the most common cause of visual impairment in childhood, with a prevalence of 1% to 4% in children in the United States. To date, no studies using noninvasive optical coherence tomographic angiography (OCTA) have measured blood flow in the retinal capillary layers in children with amblyopia. To evaluate the retinal and microvascular features using OCTA in children (<18 years) with amblyopia. This observational case-control study enrolled patients from September 1, 2016, through May 31, 2017, and was conducted from September 1, 2016, through June 30, 2017, at the Stein Eye Institute at UCLA (University of California, Los Angeles). Participants included 59 children (<18 years) with amblyopia and without amblyopia examined at a pediatric ophthalmology clinic or referred to the clinic by coinvestigators. All patients underwent comprehensive ophthalmological examination, including visual acuity, refraction, and ocular motility tests; anterior and posterior segment examination; and OCTA. Reduced superficial and deep retinal capillary vessel density on OCTA. Of the 63 eyes evaluated, 13 (21%) were amblyopic and 50 (79%) were control eyes. Of the 59 patients, the mean (SD) age of patients with amblyopia was 8.0 (4.0) years and 10.3 (3.3) years for the controls; 33 patients (56%) were female; and 5 of 13 (39%) and 27 of 46 (54%) patients in the amblyopic and control groups, respectively, were identified as white. The macular vessel density of the superficial capillary plexus was lower in the amblyopic group than in the control group in both 3 × 3-mm and 6 × 6-mm scans. After adjusting for age and refractive error, the mean (SD) difference in the superficial capillary plexus in the 6 × 6-mm scan was statistically significant (49.3% [4.1] vs 51.2% [2.9]; P = .02). Macular vessel density of the deep capillary plexus in the 6 × 6-mm scans was also considerably different between groups: mean (SD) vessel density of the deep retinal capillary plexus was 54.4% (4.7%) in the amblyopia group and 60.1% (3.3%) in the control group, with a difference of 5.7% (95% CI, 3.4%-8.1%; P = .002). The study found that OCTA reveals subnormal superficial and deep retinal capillary density in the macula of patients with amblyopia. Further studies are needed to determine the clinical relevance of this finding.

Orbital Angiogenesis and Lymphangiogenesis in Thyroid Eye Disease: An Analysis of Vascular Growth Factors with Clinical Correlation.

PubMed

Wong, Lindsay L; Lee, Nahyoung Grace; Amarnani, Dhanesh; Choi, Catherine J; Bielenberg, Diane R; Freitag, Suzanne K; D'Amore, Patricia A; Kim, Leo A

2016-09-01

The human orbit is an environment that is vulnerable to inflammation and edema in the setting of autoimmune thyroid disease. Our study investigated the tenet that orbital adipose tissue lacks lymphatic vessels and analyzed the clinicopathologic differences between patients with acute and chronic thyroid eye disease (TED). The underlying molecular mediators of blood and lymphatic vessel formation within the orbital fat also were evaluated. Retrospective cohort study. The study included fat specimens from 26 orbits of 15 patients with TED undergoing orbital decompression. Orbital fat specimens from patients without TED as well as cadaveric orbital fat served as controls. Tissue specimens were processed as formalin-fixed, paraffin-embedded sections or frozen cryosections for immunohistochemistry. Total RNA was extracted and analyzed via quantitative (real-time) reverse-transcription polymerase chain reaction. Clinicopathologic correlation was made by determining the clinical activity score (CAS) of each patient with TED. Samples were examined for vascular and lymphatic markers including podoplanin, lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), and cluster of differentiation 31 (CD31) by immunohistochemistry, as well as for mRNA levels of vascular endothelial growth factor (VEGF), VEGF receptors, semaphorin 3F, neuropilin 1, neuropilin 2, podoplanin, and LYVE-1 by quantitative (real-time) reverse-transcription polymerase chain reaction. Clinicopathologic correlation revealed increased staining of CD31-positive blood vessels in patients with acute TED with a CAS more than 4, as well as rare staining of podoplanin-positive lymphatic vessels within acutely inflamed orbital fat tissue. Additionally, quantitative (real-time) reverse-transcription polymerase chain reaction analysis demonstrated increased expression of VEGF receptor (VEGFR) 2 as well as VEGF signaling molecules VEGF-A, VEGF-C, and VEGF-D. In acute TED, compared with chronic TED and control orbital fat, there is increased blood vessel density, suggesting neovascularization and rare lymphatic vessels suggestive of limited lymphangiogenesis. This proangiogenic and prolymphangiogenic microenvironment is likely the result of the increased expression of VEGFR-2, VEGF-A, VEGF-C, and VEGF-D. These findings imply that orbital edema in acute TED may be mediated, in part, by both the formation of new, immature blood vessels and the formation of lymphatic capillaries that are functionally incapable of draining interstitial fluid. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Vessel extraction in retinal images using automatic thresholding and Gabor Wavelet.

PubMed

Ali, Aziah; Hussain, Aini; Wan Zaki, Wan Mimi Diyana

2017-07-01

Retinal image analysis has been widely used for early detection and diagnosis of multiple systemic diseases. Accurate vessel extraction in retinal image is a crucial step towards a fully automated diagnosis system. This work affords an efficient unsupervised method for extracting blood vessels from retinal images by combining existing Gabor Wavelet (GW) method with automatic thresholding. Green channel image is extracted from color retinal image and used to produce Gabor feature image using GW. Both green channel image and Gabor feature image undergo vessel-enhancement step in order to highlight blood vessels. Next, the two vessel-enhanced images are transformed to binary images using automatic thresholding before combined to produce the final vessel output. Combining the images results in significant improvement of blood vessel extraction performance compared to using individual image. Effectiveness of the proposed method was proven via comparative analysis with existing methods validated using publicly available database, DRIVE.

Design of multichannel laser interferometry for W7-X

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kornejew, P.; Hirsch, M.; Bindemann, T.

2006-10-15

An eight channel interferometer is developed for density feedback control and the continuous measurement of electron density profiles in the stellarator W7-X. An additional sightline is launched in the geometry of the Thomson scattering for cross calibration. Due to the W7-X coil geometry access is strongly restricted. This motivates the optimization of the sightline geometry and design studies for supplementary chords. In-vessel retroreflectors will be used and inserted in the first wall elements. To cope with associated mechanical vibrations and thermal drifts during the discharges with envisaged duration of 30 min either two-color or second harmonic interferometry techniques must bemore » applied. Optimum wavelengths are found to be about 10 and 5 {mu}m. A CO{sub 2}/CO interferometer (10 {mu}m/5 {mu}m) will be tested and compared with an existing CO{sub 2}/HeNe test interferometer. A special difficulty of remotely operated diagnostics is the need of long transmission lines with a path length of about 60 m required from the diagnostics location to the torus hall and back. Different arrangements will be compared.« less

Impact of image quality on OCT angiography based quantitative measurements.

PubMed

Al-Sheikh, Mayss; Ghasemi Falavarjani, Khalil; Akil, Handan; Sadda, SriniVas R

2017-01-01

To study the impact of image quality on quantitative measurements and the frequency of segmentation error with optical coherence tomography angiography (OCTA). Seventeen eyes of 10 healthy individuals were included in this study. OCTA was performed using a swept-source device (Triton, Topcon). Each subject underwent three scanning sessions 1-2 min apart; the first two scans were obtained under standard conditions and for the third session, the image quality index was reduced using application of a topical ointment. En face OCTA images of the retinal vasculature were generated using the default segmentation for the superficial and deep retinal layer (SRL, DRL). Intraclass correlation coefficient (ICC) was used as a measure for repeatability. The frequency of segmentation error, motion artifact, banding artifact and projection artifact was also compared among the three sessions. The frequency of segmentation error, and motion artifact was statistically similar between high and low image quality sessions (P = 0.707, and P = 1 respectively). However, the frequency of projection and banding artifact was higher with a lower image quality. The vessel density in the SRL was highly repeatable in the high image quality sessions (ICC = 0.8), however, the repeatability was low, comparing the high and low image quality measurements (ICC = 0.3). In the DRL, the repeatability of the vessel density measurements was fair in the high quality sessions (ICC = 0.6 and ICC = 0.5, with and without automatic artifact removal, respectively) and poor comparing high and low image quality sessions (ICC = 0.3 and ICC = 0.06, with and without automatic artifact removal, respectively). The frequency of artifacts is higher and the repeatability of the measurements is lower with lower image quality. The impact of image quality index should be always considered in OCTA based quantitative measurements.

Comparing algorithms for automated vessel segmentation in computed tomography scans of the lung: the VESSEL12 study

PubMed Central

Rudyanto, Rina D.; Kerkstra, Sjoerd; van Rikxoort, Eva M.; Fetita, Catalin; Brillet, Pierre-Yves; Lefevre, Christophe; Xue, Wenzhe; Zhu, Xiangjun; Liang, Jianming; Öksüz, İlkay; Ünay, Devrim; Kadipaşaogandcaron;lu, Kamuran; Estépar, Raúl San José; Ross, James C.; Washko, George R.; Prieto, Juan-Carlos; Hoyos, Marcela Hernández; Orkisz, Maciej; Meine, Hans; Hüllebrand, Markus; Stöcker, Christina; Mir, Fernando Lopez; Naranjo, Valery; Villanueva, Eliseo; Staring, Marius; Xiao, Changyan; Stoel, Berend C.; Fabijanska, Anna; Smistad, Erik; Elster, Anne C.; Lindseth, Frank; Foruzan, Amir Hossein; Kiros, Ryan; Popuri, Karteek; Cobzas, Dana; Jimenez-Carretero, Daniel; Santos, Andres; Ledesma-Carbayo, Maria J.; Helmberger, Michael; Urschler, Martin; Pienn, Michael; Bosboom, Dennis G.H.; Campo, Arantza; Prokop, Mathias; de Jong, Pim A.; Ortiz-de-Solorzano, Carlos; Muñoz-Barrutia, Arrate; van Ginneken, Bram

2016-01-01

The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of different algorithms to identify vessels in thoracic computed tomography (CT) scans. Vessel segmentation is fundamental in computer aided processing of data generated by 3D imaging modalities. As manual vessel segmentation is prohibitively time consuming, any real world application requires some form of automation. Several approaches exist for automated vessel segmentation, but judging their relative merits is difficult due to a lack of standardized evaluation. We present an annotated reference dataset containing 20 CT scans and propose nine categories to perform a comprehensive evaluation of vessel segmentation algorithms from both academia and industry. Twenty algorithms participated in the VESSEL12 challenge, held at International Symposium on Biomedical Imaging (ISBI) 2012. All results have been published at the VESSEL12 website http://vessel12.grand-challenge.org. The challenge remains ongoing and open to new participants. Our three contributions are: (1) an annotated reference dataset available online for evaluation of new algorithms; (2) a quantitative scoring system for objective comparison of algorithms; and (3) performance analysis of the strengths and weaknesses of the various vessel segmentation methods in the presence of various lung diseases. PMID:25113321

Safety profile and long-term engraftment of human CD31+ blood progenitors in bone tissue engineering.

PubMed

Zigdon-Giladi, Hadar; Elimelech, Rina; Michaeli-Geller, Gal; Rudich, Utai; Machtei, Eli E

2017-07-01

Endothelial progenitor cells (EPCs) participate in angiogenesis and induce favorable micro-environments for tissue regeneration. The efficacy of EPCs in regenerative medicine is extensively studied; however, their safety profile remains unknown. Therefore, our aims were to evaluate the safety profile of human peripheral blood-derived EPCs (hEPCs) and to assess the long-term efficacy of hEPCs in bone tissue engineering. hEPCs were isolated from peripheral blood, cultured and characterized. β tricalcium phosphate scaffold (βTCP, control) or 10 6 hEPCs loaded onto βTCP were transplanted in a nude rat calvaria model. New bone formation and blood vessel density were analyzed using histomorphometry and micro-computed tomography (CT). Safety of hEPCs using karyotype analysis, tumorigenecity and biodistribution to target organs was evaluated. On the cellular level, hEPCs retained their karyotype during cell expansion (seven passages). Five months following local hEPC transplantation, on the tissue and organ level, no inflammatory reaction or dysplastic change was evident at the transplanted site or in distant organs. Direct engraftment was evident as CD31 human antigens were detected lining vessel walls in the transplanted site. In distant organs human antigens were absent, negating biodistribution. Bone area fraction and bone height were doubled by hEPC transplantation without affecting mineral density and bone architecture. Additionally, local transplantation of hEPCs increased blood vessel density by nine-fold. Local transplantation of hEPCs showed a positive safety profile. Furthermore, enhanced angiogenesis and osteogenesis without mineral density change was found. These results bring us one step closer to first-in-human trials using hEPCs for bone regeneration. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Evolution of US maize (Zea mays L.) root architectural and anatomical phenes over the past 100 years corresponds to increased tolerance of nitrogen stress.

PubMed

York, Larry M; Galindo-Castañeda, Tania; Schussler, Jeffrey R; Lynch, Jonathan P

2015-04-01

Increasing the nitrogen use efficiency of maize is an important goal for food security and agricultural sustainability. In the past 100 years, maize breeding has focused on yield and above-ground phenes. Over this period, maize cultivation has changed from low fertilizer inputs and low population densities to intensive fertilization and dense populations. The authors hypothesized that through indirect selection the maize root system has evolved phenotypes suited to more intense competition for nitrogen. Sixteen maize varieties representing commercially successful lines over the past century were planted at two nitrogen levels and three planting densities. Root systems of the most recent material were 7 º more shallow, had one less nodal root per whorl, had double the distance from nodal root emergence to lateral branching, and had 14% more metaxylem vessels, but total mextaxylem vessel area remained unchanged because individual metaxylem vessels had 12% less area. Plasticity was also observed in cortical phenes such as aerenchyma, which increased at greater population densities. Simulation modelling with SimRoot demonstrated that even these relatively small changes in root architecture and anatomy could increase maize shoot growth by 16% in a high density and high nitrogen environment. The authors concluded that evolution of maize root phenotypes over the past century is consistent with increasing nitrogen use efficiency. Introgression of more contrasting root phene states into the germplasm of elite maize and determination of the functional utility of these phene states in multiple agronomic conditions could contribute to future yield gains. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

MDMA ("Ecstasy") and its association with cerebrovascular accidents: preliminary findings.

PubMed

Reneman, L; Habraken, J B; Majoie, C B; Booij, J; den Heeten, G J

2000-01-01

Abuse of the popular recreational drug "Ecstasy" (MDMA) has been linked to the occurrence of cerebrovascular accidents. It is known that MDMA alters brain serotonin (5-HT) concentrations and that brain postsynaptic 5-HT(2) receptors play a role in the regulation of brain microvasculature. Therefore, we used brain imaging to find out whether MDMA use predisposes one to cerebrovascular accidents by altering brain 5-HT neurotransmission. The effects of MDMA use on brain cortical 5-HT(2A) receptor densities were studied using [(123)I]R91150 single-photon emission CT in 10 abstinent recent MDMA users, five former MDMA users, and 10 healthy control subjects. Furthermore, to examine whether changes in brain 5-HT(2A) receptor densities are associated with alterations in blood vessel volumes, we calculated relative cerebral blood volume maps from dynamic MR imaging sets in five MDMA users and six healthy control subjects. An analysis of variance revealed that mean cortical [(123)I]R91150 binding ratios were significantly lower in recent MDMA users than in former MDMA users and control subjects. This finding suggests down-regulation of 5-HT(2) receptors caused by MDMA-induced 5-HT release. Furthermore, in MDMA users, low cortical 5-HT(2) receptor densities were significantly associated with low cerebral blood vessel volumes (implicating vasoconstriction) and high cortical 5-HT(2) receptor densities with high cerebral blood vessel volumes (implicating vasodilatation) in specific brain regions. These findings suggest a relationship between the serotonergic system and an altered regulation of 5-HT(2) receptors in human MDMA users. MDMA users may therefore be at risk for cerebrovascular accidents resulting from alterations in the 5-HT neurotransmission system.

Method and apparatus for waste destruction using supercritical water oxidation

DOEpatents

Haroldsen, Brent Lowell; Wu, Benjamin Chiau-pin

2000-01-01

The invention relates to an improved apparatus and method for initiating and sustaining an oxidation reaction. A hazardous waste, is introduced into a reaction zone within a pressurized containment vessel. An oxidizer, preferably hydrogen peroxide, is mixed with a carrier fluid, preferably water, and the mixture is heated until the fluid achieves supercritical conditions of temperature and pressure. The heating means comprise cartridge heaters placed in closed-end tubes extending into the center region of the pressure vessel along the reactor longitudinal axis. A cooling jacket surrounds the pressure vessel to remove excess heat at the walls. Heating and cooling the fluid mixture in this manner creates a limited reaction zone near the center of the pressure vessel by establishing a steady state density gradient in the fluid mixture which gradually forces the fluid to circulate internally. This circulation allows the fluid mixture to oscillate between supercritical and subcritical states as it is heated and cooled.

Ray tracing analysis of overlapping objects in refraction contrast imaging.

PubMed

Hirano, Masatsugu; Yamasaki, Katsuhito; Okada, Hiroshi; Sakurai, Takashi; Kondoh, Takeshi; Katafuchi, Tetsuro; Sugimura, Kazuro; Kitazawa, Sohei; Kitazawa, Riko; Maeda, Sakan; Tamura, Shinichi

2005-08-01

We simulated refraction contrast imaging in overlapping objects using the ray tracing method. The easiest case, in which two columnar objects (blood vessels) with a density of 1.0 [g/cm3], run at right angles in air, was calculated. For absorption, we performed simulation using the Snell law adapted to the object's boundary. A pair of bright and dark spot results from the interference of refracted X-rays where the blood vessels crossed. This has the possibility of increasing the visibility of the image.

Temperature-Jump Relaxation Kinetics at Liquid/Solid Interfaces: Fluorescence Thermometry of Porous Silica Heated by a Joule Discharge

DTIC Science & Technology

1991-05-22

for understanding reaction mechanisms responsible for the steady-state behavior and determining the dispersion of rates in cases where inhomogeneities...derivatized by the following procedure. Three grams of the silica was placed in a dry reaction vessel consisting of a three neck flask, addition funnel...to the reaction vessel , taking care to avoid contact with the air. A five-fold molar equivalent excess of ODS (based on the silanol 8 density of the

Method for making monolithic metal oxide aerogels

DOEpatents

Coronado, Paul R.

1999-01-01

Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The containment vessel is enclosed within an aqueous atmosphere that is above the supercritical temperature and pressure of the solvent of the metal alkoxide solution.

Glucose transporter distribution in the vessels of the central nervous system of the axolotl Ambystoma mexicanum (Urodela: Ambystomatidae).

PubMed

Lazzari, Maurizio; Bettini, Simone; Ciani, Franco; Franceschini, Valeria

2008-10-01

The GLUT-1 isoform of the glucose transporter is commonly considered a reliable molecular marker of blood-brain barrier endothelia in the neural vasculature organized in a three-dimensional network of single vessels. The central nervous system of the axolotl Ambystoma mexicanum is characterized by a vascular architecture that contains both single and paired vessels. The presence and distribution of the GLUT-1 transporter are studied in this urodele using both immunoperoxidase histochemistry and immunogold technique. Light microscopy reveals immunopositivity in both parenchymal and meningeal vessels. The transverse-sectioned pairs of vessels do not show the same size. Furthermore, in the same pair, the two elements often differ in diameter. The main regions of the central nervous system show a different percentage of the paired structures. Only immunogold cytochemistry reveals different staining intensity in the two adjoined elements of a vascular pair. Colloidal gold particles show an asymmetric distribution in the endothelia of both single and paired vessels. These particles are more numerous on the abluminal surface than on the luminal one. The particle density is calculated in both vascular types. The different values could indicate functional differences between single and paired vessels and between the two adjoined elements of a pair, regarding glucose transport.

The pattern of renal vessels in live related potential donors pool. A multislice computed tomography angiography review.

PubMed

Mishra, Anuj; Ehtuish, Ehtuish F

2006-06-01

To assess the renal vessel anatomy, compare the findings with the perioperative findings, to determine the sensitivity of multislice computed tomography (CT) angiography in the work-up of live potential donors and to discuss and compare the results of the present study with the reported results using single slice CT, magnetic resonance (MRI) and conventional angiography (CA). Retrospective analysis of the angiographic data of 118 of prospective live related kidney donors was carried out from October 2004 to August 2005 at the National Organ Transplant Centre, Tripoli Central Hospital, Libya. All donors underwent renal angiography on multislice (16-slice) CT scan using 80 cc intravenous contrast with 1.25 mm slice thickness followed by maximum intensity projection (MIP) and volume rendering techniques (VRT) post-processing algorithms. The number of vessels, vessel bifurcation, vessel morphology and venous anatomy were analyzed and the findings were compared with the surgical findings. Multislice spiral CT angiography (MSCTA) showed clear delineation of the main renal arteries in all donors with detailed vessel morphology. The study revealed 100% sensitivity in detection of accessory renal vessels, with an overall incidence of 26.7%, which is the most common distribution in the parahilar region. The present study showed 100% sensitivity in the visualization and detection of main and accessory renal vessels. These results were comparable with conventional angiography which has so far been considered as the gold standard and were found superior in specificity and accuracy to the use of single slice CT (SSCT) and MR in the angiographic work-up of live renal donors. Due to improved detection of accessory vessels less than 2 mm in diameter, a higher incidence of aberrant vessels was seen on the right side as has been suggested so far.

Microvessel Density Evaluation of the Effect of Enamel Matrix Derivative on Soft Tissue After Implant Placement: A Preliminary Study.

PubMed

Guimarães, George Furtado; de Araújo, Vera Cavalcanti; Nery, James Carlos; Peruzzo, Daiane Cristina; Soares, Andresa Borges

2015-01-01

Enamel matrix derivative (EMD) is commonly used in periodontal therapy and has been used successfully for periodontal regeneration. In addition, this material has a possible angiogenic effect that has been associated with enhanced wound healing. The aim of this study was to evaluate the effect of EMD on microvessel density (angiogenesis) on the soft tissues surrounding newly placed implants after 14 days. Five patients were selected, each requiring at least one implant on each side of the maxilla, in a split-mouth experimental design. The implants were placed in a two-stage procedure. Each side was then randomized as test or control. On the test side, 0.1 mL of EMD was topically applied to the soft tissues surrounding the implants, while the control side did not receive any treatment. Second-stage surgery was performed after 14 days. A 6-mm punch biopsy was performed for each implant, with the samples subsequently prepared for histology and immunohistochemistry. Quantitative vascularization analysis was performed, which involved counting three areas or "hotspots" containing vessels strongly positive for CD34 and CD105, a pan-endothelial and new vessel marker, respectively. There was no significant difference between test and control groups when evaluating the formation of new blood vessels. The total number of blood vessels, however, was significantly higher in the group treated with EMD (test group). Within the limits of the present study, it can be concluded that topical application of EMD on the soft tissues surrounding newly placed implants resulted in an increased number of blood vessels at 14 days, suggesting that EMD may play a beneficial role in this aspect of wound healing.

The muscle contraction mode determines lymphangiogenesis differentially in rat skeletal and cardiac muscles by modifying local lymphatic extracellular matrix microenvironments.

PubMed

Greiwe, L; Vinck, M; Suhr, F

2016-05-01

Lymphatic vessels are of special importance for tissue homeostasis, and increases of their density may foster tissue regeneration. Exercise could be a relevant tool to increase lymphatic vessel density (LVD); however, a significant lack of knowledge remains to understand lymphangiogenesis in skeletal muscles upon training. Interestingly, training-induced lymphangiogenesis has never been studied in the heart. We studied lymphangiogenesis and LVD upon chronic concentric and chronic eccentric muscle contractions in both rat skeletal (Mm. Edl and Sol) and cardiac muscles. We found that LVD decreased in both skeletal muscles specifically upon eccentric training, while this contraction increased LVD in cardiac tissue. These observations were supported by opposing local remodelling of lymphatic vessel-specific extracellular matrix components in skeletal and cardiac muscles and protein levels of lymphatic markers (Lyve-1, Pdpn, Vegf-C/D). Confocal microscopy further revealed transformations of lymphatic vessels into vessels expressing both blood (Cav-1) and lymphatic (Vegfr-3) markers upon eccentric training specifically in skeletal muscles. In addition and phenotype supportive, we found increased inflammation (NF-κB/p65, Il-1β, Ifn-γ, Tnf-α and MPO(+) cells) in eccentrically stressed skeletal, but decreased levels in cardiac muscles. Our data provide novel mechanistic insights into lymphangiogenic processes in skeletal and cardiac muscles upon chronic muscle contraction modes and demonstrate that both tissues adapt in opposing manners specifically to eccentric training. These data are highly relevant for clinical applications, because eccentric training serves as a sufficient strategy to increase LVD and to decrease inflammation in cardiac tissue, for example in order to reduce tissue abortion in transplantation settings. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Quantitative outcome measures for systemic sclerosis-related Microangiopathy - Reliability of image acquisition in Nailfold Capillaroscopy.

PubMed

Dinsdale, Graham; Moore, Tonia; O'Leary, Neil; Berks, Michael; Roberts, Christopher; Manning, Joanne; Allen, John; Anderson, Marina; Cutolo, Maurizio; Hesselstrand, Roger; Howell, Kevin; Pizzorni, Carmen; Smith, Vanessa; Sulli, Alberto; Wildt, Marie; Taylor, Christopher; Murray, Andrea; Herrick, Ariane L

2017-09-01

Nailfold capillaroscopic parameters hold increasing promise as outcome measures for clinical trials in systemic sclerosis (SSc). Their inclusion as outcomes would often naturally require capillaroscopy images to be captured at several time points during any one study. Our objective was to assess repeatability of image acquisition (which has been little studied), as well as of measurement. 41 patients (26 with SSc, 15 with primary Raynaud's phenomenon) and 10 healthy controls returned for repeat high-magnification (300×) videocapillaroscopy mosaic imaging of 10 digits one week after initial imaging (as part of a larger study of reliability). Images were assessed in a random order by an expert blinded observer and 4 outcome measures extracted: (1) overall image grade and then (where possible) distal vessel locations were marked, allowing (2) vessel density (across the whole nailfold) to be calculated (3) apex width measurement and (4) giant vessel count. Intra-rater, intra-visit and intra-rater inter-visit (baseline vs. 1week) reliability were examined in 475 and 392 images respectively. A linear, mixed-effects model was used to estimate variance components, from which intra-class correlation coefficients (ICCs) were determined. Intra-visit and inter-visit reliability estimates (ICCs) were (respectively): overall image grade, 0.97 and 0.90; vessel density, 0.92 and 0.65; mean vessel width, 0.91 and 0.79; presence of giant capillary, 0.68 and 0.56. These estimates were conditional on each parameter being measurable. Within-operator image analysis and acquisition are reproducible. Quantitative nailfold capillaroscopy, at least with a single observer, provides reliable outcome measures for clinical studies including randomised controlled trials. Copyright © 2017 Elsevier Inc. All rights reserved.

Fibroblast growth factor 2 is an essential cardioprotective factor in a closed‐chest model of cardiac ischemia‐reperfusion injury

PubMed Central

House, Stacey L.; Wang, Joy; Castro, Angela M.; Weinheimer, Carla; Kovacs, Attila; Ornitz, David M.

2015-01-01

Abstract Fibroblast growth factor 2 (FGF2) is cardioprotective in in vivo models of myocardial infarction; however, whether FGF2 has a protective role in in vivo ischemia‐reperfusion (IR) injury, a model that more closely mimics acute myocardial infarction in humans, is not known. To assess the cardioprotective efficacy of endogenous FGF2, mice lacking a functional Fgf2 gene (Fgf2−/−) and wild‐type controls were subjected to closed‐chest regional cardiac IR injury (90 min ischemia, 7 days reperfusion). Fgf2−/− mice had significantly increased myocardial infarct size and significantly worsened cardiac function compared to wild‐type controls at both 1 and 7 days post‐IR injury. Pathophysiological analysis showed that at 1 day after IR injury Fgf2−/− mice have worsened cardiac strain patterns and increased myocardial cell death. Furthermore, at 7 days post‐IR injury, Fgf2−/− mice showed a significantly reduced cardiac hypertrophic response, decreased cardiac vessel density, and increased vessel diameter in the peri‐infarct area compared to wild‐type controls. These data reveal both acute cardioprotective and a longer term proangiogenic potential of endogenous FGF2 in a clinically relevant, in vivo, closed‐chest regional cardiac IR injury model that mimics acute myocardial infarction. PMID:25626875

Structural Properties of EB-Welded AlSi10Mg Thin-Walled Pressure Vessels Produced by AM-SLM Technology

NASA Astrophysics Data System (ADS)

Nahmany, Moshe; Stern, Adin; Aghion, Eli; Frage, Nachum

2017-10-01

Additive manufacturing of metals by selective laser melting (AM-SLM) is hampered by significant limitations in product size due to the limited dimensions of printing trays. Electron beam welding (EBW) is a well-established process that results in relatively minor metallurgical modifications in workpieces due to the ability of EBW to pass high-density energy to the related substance. The present study aims to evaluate structural properties of EB-welded AlSi10Mg thin-walled pressure vessels produced from components prepared by SLM technology. Following the EB welding process, leak and burst tests were conducted, as was fractography analysis. The welded vessels showed an acceptable holding pressure of 30 MPa, with a reasonable residual deformation up to 2.3% and a leak rate better than 1 × 10-8 std-cc s-1 helium. The failures that occurred under longitudinal stresses reflected the presence of two weak locations in the vessels, i.e., the welded joint region and the transition zone between the vessel base and wall. Fractographic analysis of the fracture surfaces of broken vessels displayed the ductile mode of the rupture, with dimples of various sizes, depending on the failure location.

Nonlinear analysis of a model of vascular tumour growth and treatment

NASA Astrophysics Data System (ADS)

Tao, Youshan; Yoshida, Norio; Guo, Qian

2004-05-01

We consider a mathematical model describing the evolution of a vascular tumour in response to traditional chemotherapy. The model is a free boundary problem for a system of partial differential equations governing intratumoural drug concentration, cancer cell density and blood vessel density. Tumour cells consist of two types of competitive cells that have different proliferation rates and different sensitivities to drugs. The balance between cell proliferation and death generates a velocity field that drives tumour cell movement. The tumour surface is a moving boundary. The purpose of this paper is to establish a rigorous mathematical analysis of the model for studying the dynamics of intratumoural blood vessels and to explore drug dosage for the successful treatment of a tumour. We also study numerically the competitive effects of the two cell types on tumour growth.

Measurement of toroidal vessel eddy current during plasma disruption on J-TEXT.

PubMed

Liu, L J; Yu, K X; Zhang, M; Zhuang, G; Li, X; Yuan, T; Rao, B; Zhao, Q

2016-01-01

In this paper, we have employed a thin, printed circuit board eddy current array in order to determine the radial distribution of the azimuthal component of the eddy current density at the surface of a steel plate. The eddy current in the steel plate can be calculated by analytical methods under the simplifying assumptions that the steel plate is infinitely large and the exciting current is of uniform distribution. The measurement on the steel plate shows that this method has high spatial resolution. Then, we extended this methodology to a toroidal geometry with the objective of determining the poloidal distribution of the toroidal component of the eddy current density associated with plasma disruption in a fusion reactor called J-TEXT. The preliminary measured result is consistent with the analysis and calculation results on the J-TEXT vacuum vessel.

Dienogest reduces proliferation, NGF expression and nerve fiber density in human adenomyosis.

PubMed

Takeuchi, Arisa; Koga, Kaori; Miyashita, Mariko; Makabe, Tomoko; Sue, Fusako; Harada, Miyuki; Hirata, Tetsuya; Hirota, Yasushi; Fujii, Tomoyuki; Osuga, Yutaka

2016-12-01

To evaluate the in vivo effect of dienogest on proliferation, apoptosis, aromatase expression, vascular density, nerve growth factor (NGF) expression and nerve fiber density in human adenomyosis tissue. Twelve women who underwent hysterectomy for adenomyosis were enrolled. Six patients received dienogest treatment prior to hysterectomy (dienogest group), and age-matched six patients who had not received any hormonal treatment for ≥3 months before surgery (control group). Cell proliferation, vascular and nerve fiber density in adenomyosis tissue were evaluated by staining for Ki67, von Willebrand factor and PGP9.5, respectively. Apoptosis was detected using the TUNEL assay. The expression aromatase and NGF were evaluated by staining for corresponding antibodies. The proportion of Ki67 positive epithelial cells was significantly lower in samples from dienogest-treated patients in comparison with controls (p<0.05). The density of blood vessels in adenomyosis was marginally lower in the dienogest group in comparison with controls but statistical significance was not reached (p=0.07). The intensity of NGF expression and the density of nerve fibers were significantly lower in the dienogest group compared with controls (p<0.05 for both). This study demonstrates that adenomyosis, taken from patients treated with dienogest, shows remarkable histological features, such as reductions in proliferation, NGF expression and nerve fiber density. These findings indicate the impact of dienogest on local histological events, and explains its therapeutic effect on adenomyosis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Technical Factors Influencing Cone Packing Density Estimates in Adaptive Optics Flood Illuminated Retinal Images

PubMed Central

Lombardo, Marco; Serrao, Sebastiano; Lombardo, Giuseppe

2014-01-01

Purpose To investigate the influence of various technical factors on the variation of cone packing density estimates in adaptive optics flood illuminated retinal images. Methods Adaptive optics images of the photoreceptor mosaic were obtained in fifteen healthy subjects. The cone density and Voronoi diagrams were assessed in sampling windows of 320×320 µm, 160×160 µm and 64×64 µm at 1.5 degree temporal and superior eccentricity from the preferred locus of fixation (PRL). The technical factors that have been analyzed included the sampling window size, the corrected retinal magnification factor (RMFcorr), the conversion from radial to linear distance from the PRL, the displacement between the PRL and foveal center and the manual checking of cone identification algorithm. Bland-Altman analysis was used to assess the agreement between cone density estimated within the different sampling window conditions. Results The cone density declined with decreasing sampling area and data between areas of different size showed low agreement. A high agreement was found between sampling areas of the same size when comparing density calculated with or without using individual RMFcorr. The agreement between cone density measured at radial and linear distances from the PRL and between data referred to the PRL or the foveal center was moderate. The percentage of Voronoi tiles with hexagonal packing arrangement was comparable between sampling areas of different size. The boundary effect, presence of any retinal vessels, and the manual selection of cones missed by the automated identification algorithm were identified as the factors influencing variation of cone packing arrangements in Voronoi diagrams. Conclusions The sampling window size is the main technical factor that influences variation of cone density. Clear identification of each cone in the image and the use of a large buffer zone are necessary to minimize factors influencing variation of Voronoi diagrams of the cone mosaic. PMID:25203681

Technical factors influencing cone packing density estimates in adaptive optics flood illuminated retinal images.

PubMed

Lombardo, Marco; Serrao, Sebastiano; Lombardo, Giuseppe

2014-01-01

To investigate the influence of various technical factors on the variation of cone packing density estimates in adaptive optics flood illuminated retinal images. Adaptive optics images of the photoreceptor mosaic were obtained in fifteen healthy subjects. The cone density and Voronoi diagrams were assessed in sampling windows of 320×320 µm, 160×160 µm and 64×64 µm at 1.5 degree temporal and superior eccentricity from the preferred locus of fixation (PRL). The technical factors that have been analyzed included the sampling window size, the corrected retinal magnification factor (RMFcorr), the conversion from radial to linear distance from the PRL, the displacement between the PRL and foveal center and the manual checking of cone identification algorithm. Bland-Altman analysis was used to assess the agreement between cone density estimated within the different sampling window conditions. The cone density declined with decreasing sampling area and data between areas of different size showed low agreement. A high agreement was found between sampling areas of the same size when comparing density calculated with or without using individual RMFcorr. The agreement between cone density measured at radial and linear distances from the PRL and between data referred to the PRL or the foveal center was moderate. The percentage of Voronoi tiles with hexagonal packing arrangement was comparable between sampling areas of different size. The boundary effect, presence of any retinal vessels, and the manual selection of cones missed by the automated identification algorithm were identified as the factors influencing variation of cone packing arrangements in Voronoi diagrams. The sampling window size is the main technical factor that influences variation of cone density. Clear identification of each cone in the image and the use of a large buffer zone are necessary to minimize factors influencing variation of Voronoi diagrams of the cone mosaic.

Anatomic distribution of nerves and microvascular density in the human anterior vaginal wall: prospective study.

PubMed

Li, Ting; Liao, Qinping; Zhang, Hong; Gao, Xuelian; Li, Xueying; Zhang, Miao

2014-01-01

The presence of the G-spot (an assumed erotic sensitive area in the anterior wall of the vagina) remains controversial. We explored the histomorphological basis of the G-spot. Biopsies were drawn from a 12 o'clock direction in the distal- and proximal-third areas of the anterior vagina of 32 Chinese subjects. The total number of protein gene product 9.5-immunoreactive nerves and smooth muscle actin-immunoreactive blood vessels in each specimen was quantified using the avidin-biotin-peroxidase assay. Vaginal innervation was observed in the lamina propria and muscle layer of the anterior vaginal wall. The distal-third of the anterior vaginal wall had significantly richer small-nerve-fiber innervation in the lamina propria than the proximal-third (p = 0.000) and in the vaginal muscle layer (p = 0.006). There were abundant microvessels in the lamina propria and muscle layer, but no small vessels in the lamina propria and few in the muscle layer. Significant differences were noted in the number of microvessels when comparing the distal- with proximal-third parts in the lamina propria (p = 0.046) and muscle layer (p = 0.002). Significantly increased density of nerves and microvessels in the distal-third of the anterior vaginal wall could be the histomorphological basis of the G-spot. Distal anterior vaginal repair could disrupt the normal anatomy, neurovascular supply and function of the G-spot, and cause sexual dysfunction.

High altitude hypoxia as a factor that promotes tibial growth plate development in broiler chickens

PubMed Central

Huang, Shucheng; Zhang, Lihong; Rehman, Mujeeb Ur; Iqbal, Muhammad Kashif; Lan, Yanfang; Mehmood, Khalid; Zhang, Hui; Qiu, Gang; Nabi, Fazul; Yao, Wangyuan; Wang, Meng; Li, Jiakui

2017-01-01

Tibial dyschondroplasia (TD) is one of the most common problems in the poultry industry and leads to lameness by affecting the proximal growth plate of the tibia. However, due to the unique environmental and geographical conditions of Tibet, no case of TD has been reported in Tibetan chickens (TBCs). The present study was designed to investigate the effect of high altitude hypoxia on blood parameters and tibial growth plate development in chickens using the complete blood count, morphology, and histological examination. The results of this study showed an undesirable impact on the overall performance, body weight, and mortality of Arbor Acres chickens (AACs) exposed to a high altitude hypoxic environment. However, AACs raised under hypoxic conditions showed an elevated number of red blood cells (RBCs) and an increase in hemoglobin and hematocrit values on day 14 compared to the hypobaric normoxia group. Notably, the morphology and histology analyses showed that the size of tibial growth plates in AACs was enlarged and that the blood vessel density was also higher after exposure to the hypoxic environment for 14 days, while no such change was observed in TBCs. Altogether, our results revealed that the hypoxic environment has a potentially new role in increasing the blood vessel density of proximal tibial growth plates to strengthen and enhance the size of the growth plates, which may provide new insights for the therapeutic manipulation of hypoxia in poultry TD. PMID:28282429

Effects of Gelatin Hydrogel Loading Mitomycin C on Conjunctival Scarring in a Canine Filtration Surgery Model.

PubMed

Kojima, Shota; Sugiyama, Tetsuya; Takai, Shinji; Jin, Denan; Ueki, Mari; Oku, Hidehiro; Tabata, Yasuhiko; Ikeda, Tsunehiko

2015-04-01

To investigate the effects and toxicities of gelatin hydrogel (GH) loading mitomycin C (MMC) on IOP and conjunctival scarring in a canine model of glaucoma surgery in comparison with conventional MMC application. Glaucoma surgery models were made in six beagles. An MMC-loaded GH was implanted under the conjunctiva of one eye (GH-MMC group) and 0.04% MMC-soaked sponges were placed under the conjunctiva of the other eye (MMC group) for 5 minutes. Intraocular pressures and bleb features were then assessed for 4 weeks postoperative, followed by histological evaluation. The ratio of conjunctival area to scleral area, the densities of collagen and the numbers of fibroblasts, vessels, and proliferative cell nuclear antigen (PCNA)-positive cells were then quantified. In both groups, IOP reduction and bleb formation were maintained in a similar manner for 4 weeks postoperative. No significant difference in the ratio of conjunctival area to scleral area was found between the two groups. Collagen density and the numbers of fibroblasts and vessels were significantly lower in the MMC-treated group than in the GH-MMC-treated group. No significant difference in PCNA-positive cells was found between the two groups. Implantation of MMC-loaded GH ameliorated toxicity to conjunctiva compared with the 5-minute placement of MMC, whereas its effect on IOP reduction and bleb formation was similar. These results suggest that using GH for the application of MMC is a safer method than the conventional application of MMC in glaucoma filtration surgery.

Transient repetitive exposure to low level light therapy enhances collateral blood vessel growth in the ischemic hindlimb of the tight skin mouse.

PubMed

Zaidi, Maria; Krolikowki, John G; Jones, Deron W; Pritchard, Kirkwood A; Struve, Janine; Nandedkar, Sandhya D; Lohr, Nicole L; Pagel, Paul S; Weihrauch, Dorothée

2013-01-01

The tight skin mouse (Tsk(-/+)) is a model of scleroderma characterized by impaired vasoreactivity, increased oxidative stress, attenuated angiogenic response to VEGF and production of the angiogenesis inhibitor angiostatin. Low-level light therapy (LLLT) stimulates angiogenesis in myocardial infarction and chemotherapy-induced mucositis. We hypothesize that repetitive LLLT restores vessel growth in the ischemic hindlimb of Tsk(-/+) mice by attenuating angiostatin and enhancing angiomotin effects in vivo. C57Bl/6J and Tsk(-/+) mice underwent ligation of the femoral artery. Relative blood flow to the foot was measured using a laser Doppler imager. Tsk(-/+) mice received LLLT (670 nm, 50 mW cm(-2), 30 J cm(-2)) for 10 min per day for 14 days. Vascular density was determined using lycopersicom lectin staining. Immunofluorescent labeling, Western blot analysis and immunoprecipitation were used to determine angiostatin and angiomotin expression. Recovery of blood flow to the ischemic limb was reduced in Tsk(-/+) compared with C57Bl/6 mice 2 weeks after surgery. LLLT treatment of Tsk(-/+) mice restored blood flow to levels observed in C57Bl/6 mice. Vascular density was decreased, angiostatin expression was enhanced and angiomotin depressed in the ischemic hindlimb of Tsk(-/+) mice. LLLT treatment reversed these abnormalities. LLLT stimulates angiogenesis by increasing angiomotin and decreasing angiostatin expression in the ischemic hindlimb of Tsk(-/+) mice. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

Retinal expression of Wnt-pathway mediated genes in low-density lipoprotein receptor-related protein 5 (Lrp5) knockout mice.

PubMed

Chen, Jing; Stahl, Andreas; Krah, Nathan M; Seaward, Molly R; Joyal, Jean-Sebastian; Juan, Aimee M; Hatton, Colman J; Aderman, Christopher M; Dennison, Roberta J; Willett, Keirnan L; Sapieha, Przemyslaw; Smith, Lois E H

2012-01-01

Mutations in low-density lipoprotein receptor-related protein 5 (Lrp5) impair retinal angiogenesis in patients with familial exudative vitreoretinopathy (FEVR), a rare type of blinding vascular eye disease. The defective retinal vasculature phenotype in human FEVR patients is recapitulated in Lrp5 knockout (Lrp5(-/-)) mouse with delayed and incomplete development of retinal vessels. In this study we examined gene expression changes in the developing Lrp5(-/-) mouse retina to gain insight into the molecular mechanisms that underlie the pathology of FEVR in humans. Gene expression levels were assessed with an Illumina microarray on total RNA from Lrp5(-/-) and WT retinas isolated on postnatal day (P) 8. Regulated genes were confirmed using RT-qPCR analysis. Consistent with a role in vascular development, we identified expression changes in genes involved in cell-cell adhesion, blood vessel morphogenesis and membrane transport in Lrp5(-/-) retina compared to WT retina. In particular, tight junction protein claudin5 and amino acid transporter slc38a5 are both highly down-regulated in Lrp5(-/-) retina. Similarly, several Wnt ligands including Wnt7b show decreased expression levels. Plasmalemma vesicle associated protein (plvap), an endothelial permeability marker, in contrast, is up-regulated consistent with increased permeability in Lrp5(-/-) retinas. Together these data suggest that Lrp5 regulates multiple groups of genes that influence retinal angiogenesis and may contribute to the pathogenesis of FEVR.

Lymph microvascularization as a prognostic indicator in neuroblastoma.

PubMed

Tadeo, Irene; Gamero-Sandemetrio, Esther; Berbegall, Ana P; Gironella, Marta; Ritort, Félix; Cañete, Adela; Bueno, Gloria; Navarro, Samuel; Noguera, Rosa

2018-05-25

Neuroblastoma is the most common extra-cranial solid pediatric cancer and causes approximately 15% of all childhood deaths from cancer. Although lymphatic vasculature is a prerequisite for the maintenance of tissue fluid balance and immunity in the body, little is known about the relationship between lymphatic vascularization and prognosis in neuroblastoma. We used our previously-published custom-designed tool to close open-outline vessels and measure the density, size and shape of all lymphatic vessels and microvascular segments in 332 primary neuroblastoma contained in tissue microarrays. The results were correlated with clinical and biological features of known prognostic value and with risk of progression to establish histological lymphatic vascular patterns associated with unfavorable histology. A high proportion of irregular intermediate lymphatic capillaries and irregular small collector vessels were present in tumors from patients with metastatic stage, undifferentiating neuroblasts and/or classified in the high risk. In addition, a higher lymphatic microvascularization density was found to be predictive of overall survival. Our findings show the crucial role of lymphatic vascularization in metastatic development and maintenance of tumor tissue homeostasis. These patterns may therefore help to indicate more accurate pre-treatment risk stratification and could provide candidate targets for novel therapies.

Induction of angiogenesis and neovascularization in adjacent tissue of plasma-collagen-coated silicone implants.

PubMed

Ring, Andrej; Langer, Stefan; Tilkorn, Daniel; Goertz, Ole; Henrich, Lena; Stricker, Ingo; Steinau, Hans-Ulrich; Steinstraesser, Lars; Hauser, Joerg

2010-09-28

Formation of encapsulating, avascular fibrous tissue is deemed to decrease implant's biocompatibility and versatility. We investigated whether plasma-mediated collagen coating possesses the ability to enhance neovascularization in the vicinity of silicone implants. Plasma-treated collagen-I-coated silicone samples were placed into the dorsal skinfold chambers of female balb/c mice (n = 10). Conventional silicone served as control (n = 10). Intravital microscopy was performed within implant's surrounding tissue on days 1, 5, and 10. Functional vessel density, intervascular distance, vessel diameter, microvascular permeability, red blood cell velocity, and leukocyte-endothelium interaction were determined. Enhanced angiogenesis in the tissue surrounding plasma-pretreated collagen-coated implants was noted. Significant increase of functional vessel density due to vascular new development was observed (t test, P < .05). Analyses of microvascular permeability and red blood cell velocity displayed stable perfusion of the vascular network neighboring the surface-modified implants. Intensified vascularity due to induced angiogenesis and neovascularization in the tissue surrounding plasma-collagen-coated samples were observed. These results indicate that plasma-mediated collagen coating might be a promising technology in order to improve the biocompatibility and versatility of silicone implants.

Induction of Angiogenesis and Neovascularization in Adjacent Tissue of Plasma-Collagen–Coated Silicone Implants

PubMed Central

Ring, Andrej; Langer, Stefan; Tilkorn, Daniel; Goertz, Ole; Henrich, Lena; Stricker, Ingo; Steinau, Hans-Ulrich; Steinstraesser, Lars; Hauser, Joerg

2010-01-01

Objective: Formation of encapsulating, avascular fibrous tissue is deemed to decrease implant's biocompatibility and versatility. We investigated whether plasma-mediated collagen coating possesses the ability to enhance neovascularization in the vicinity of silicone implants. Methods: Plasma-treated collagen-I–coated silicone samples were placed into the dorsal skinfold chambers of female balb/c mice (n = 10). Conventional silicone served as control (n = 10). Intravital microscopy was performed within implant's surrounding tissue on days 1, 5, and 10. Functional vessel density, intervascular distance, vessel diameter, microvascular permeability, red blood cell velocity, and leukocyte-endothelium interaction were determined. Results: Enhanced angiogenesis in the tissue surrounding plasma-pretreated collagen-coated implants was noted. Significant increase of functional vessel density due to vascular new development was observed (t test, P < .05). Analyses of microvascular permeability and red blood cell velocity displayed stable perfusion of the vascular network neighboring the surface-modified implants. Conclusion: Intensified vascularity due to induced angiogenesis and neovascularization in the tissue surrounding plasma-collagen–coated samples were observed. These results indicate that plasma-mediated collagen coating might be a promising technology in order to improve the biocompatibility and versatility of silicone implants. PMID:20936137

Feasibility of laser-targeted photoocclusion of the choriocapillary layer in rats.

PubMed

Asrani, S; Zou, S; D'Anna, S; Lutty, G; Vinores, S A; Goldberg, M F; Zeimer, R

1997-12-01

A new method, laser-targeted photoocclusion, was developed to occlude choroidal neovascularization while minimizing damage to the overlying retina. The ability to occlude normal choriocapillary layer in rats was evaluated as a first test of the feasibility of treating choroidal neovascularization with this method. A photosensitive agent, aluminum phthalocyanine tetrasulfonate, encapsulated in heat-sensitive liposomes, was administered intravenously along with carboxyfluorescein liposomes. A low-power argon laser (retinal power density of 5.7 W/cm2) locally released a photosensitizer bolus, monitored by the simultaneous release of carboxyfluorescein. A diode laser (operating at 675 nm with a retinal power density of 0.27 W/cm2) activated the photosensitizer with its release. Vessels in the choriocapillary layer were occluded at day 3 after laser treatment and remained unchanged during the 30-day follow-up. Larger choroidal vessels and retinal capillaries remained perfused. Control experiments excluded possible effects of heat or activation of free photosensitizer. Pilot histologic studies showed no damage to the retinal pigment epithelium. Laser-targeted photoocclusion caused selective occlusion of normal choriocapillaries while sparing overlying retinal pigment epithelium and retinal vessels. The method has potential as a treatment of choroidal neovascularization that may minimize iatrogenic loss of vision.

Sublingual microcirculatory blood flow and vessel density in Sherpas at high altitude

PubMed Central

Coppel, Jonny; Court, Jo; van der Kaaij, Jildou; Vercueil, Andre; Feelisch, Martin; Levett, Denny; Mythen, Monty; Grocott, Michael P.; Martin, Daniel

2017-01-01

Anecdotal reports suggest that Sherpa highlanders demonstrate extraordinary tolerance to hypoxia at high altitude, despite exhibiting lower arterial oxygen content than acclimatized lowlanders. This study tested the hypothesis that Sherpas exposed to hypobaric hypoxia on ascent to 5,300 m develop increased microcirculatory blood flow as a means of maintaining tissue oxygen delivery. Incident dark-field imaging was used to obtain images of the sublingual microcirculation from 64 Sherpas and 69 lowlanders. Serial measurements were obtained from participants undertaking an ascent from baseline testing (35 m or 1,300 m) to Everest base camp (5,300 m) and following subsequent descent in Kathmandu (1,300 m). Microcirculatory flow index and heterogeneity index were used to provide indexes of microcirculatory flow, while capillary density was assessed using small vessel density. Sherpas demonstrated significantly greater microcirculatory blood flow at Everest base camp, but not at baseline testing or on return in Kathmandu, than lowlanders. Additionally, blood flow exhibited greater homogeneity at 5,300 and 1,300 m (descent) in Sherpas than lowlanders. Sublingual small vessel density was not different between the two cohorts at baseline testing or at 1,300 m; however, at 5,300 m, capillary density was up to 30% greater in Sherpas. These data suggest that Sherpas can maintain a significantly greater microcirculatory flow per unit time and flow per unit volume of tissue at high altitude than lowlanders. These findings support the notion that peripheral vascular factors at the microcirculatory level may be important in the process of adaptation to hypoxia. NEW & NOTEWORTHY Sherpa highlanders demonstrate extraordinary tolerance to hypoxia at high altitude, yet the physiological mechanisms underlying this tolerance remain unknown. In our prospective study, conducted on healthy volunteers ascending to Everest base camp (5,300 m), we demonstrated that Sherpas have a higher sublingual microcirculatory blood flow and greater capillary density at high altitude than lowlanders. These findings support the notion that the peripheral microcirculation plays a key role in the process of long-term adaptation to hypoxia. PMID:28126908

Control system for a small fission reactor

DOEpatents

Burelbach, J.P.; Kann, W.J.; Saiveau, J.G.

1985-02-08

A system for controlling the reactivity of a small fission reactor includes an elongated, flexible hollow tube in the general form of a helical coiled spring axially positioned around and outside of the reactor vessel in an annular space between the reactor vessel and a surrounding cylindrical-shaped neutron reflector. A neutron absorbing material is provided within the hollow tube with the rate of the reaction controlled by the extension and compression of the hollow tube, e.g., extension of the tube increases reactivity while its compression reduces reactivity, in varying the amount of neutron absorbing material disposed between the reactor vessel and the neutron reflector. Conventional mechanical displacement means may be employed to control the coil density of the hollow tube as desired.

Heat sink effect on tumor ablation characteristics as observed in monopolar radiofrequency, bipolar radiofrequency, and microwave, using ex vivo calf liver model.

PubMed

Pillai, Krishna; Akhter, Javid; Chua, Terence C; Shehata, Mena; Alzahrani, Nayef; Al-Alem, Issan; Morris, David L

2015-03-01

Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink.

Heat Sink Effect on Tumor Ablation Characteristics as Observed in Monopolar Radiofrequency, Bipolar Radiofrequency, and Microwave, Using Ex Vivo Calf Liver Model

PubMed Central

Pillai, Krishna; Akhter, Javid; Chua, Terence C.; Shehata, Mena; Alzahrani, Nayef; Al-Alem, Issan; Morris, David L.

2015-01-01

Abstract Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices. With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored. With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres. Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected. Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5. MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink. PMID:25738477

Expression of angiogenic factors and plexiform lesions in the lungs of broiler and layer chickens: A comparison.

PubMed

Tan, X; Shao, F-J; Fan, G-J; Ying, Y-T

2018-05-01

Plexiform lesions are characteristic histological changes of pulmonary arteries in human patients with severe pulmonary arterial hypertension (PAH) and are regarded as angiogenic lesions. Meat-type broiler chickens are susceptible to PAH and can develop plexiform lesions spontaneously. Whether the lesion development in broilers is associated with PAH predisposition and lung angiogenic environment remains unclear. Moreover, little is known about the cellular origin of these structures. In this work, plexiform lesions were detected in both layer chickens (a strain known to be resistant to PAH) and broiler chickens aged between 1 and 6 wk with normal pulmonary arterial pressures. Within each of the sampled ages, the lesion density did not differ between strains, with an exception of wk 4 when broiler was higher than layer. In contrast to the trend of age-related decline in layers, lesion densities in broilers demonstrated bi-phasic alterations characterized by a gradual decrease during wk 1 to 3 followed by a sudden increase at wk 4. The mRNA of 6 angiogenic factors in the lung tissue, namely, vascular endothelial growth factor receptor (VEGFR)-2, angiopoietin (Ang)-1, angiopoietin receptor Tie-2, transforming growth factor (TGF)-β1, hepatocyte growth factor (HGF), and interleukin (IL)-8, were differentially expressed between strains. However, none of them was found to be significantly correlated with the lesion density by strain and age-adjusted partial correlation analysis. An in vivo experiment revealed impaired differentiation of endothelial progenitor cells (EPC) into endothelial cells during the producing of plexiform lesions, as evidenced by increased expression of endothelial CD133, a maker of EPC, but reduced expression of CD31, a marker of mature endothelial cells, in the parent vessels of plexiform lesions compared to normal vessels. Collectively, it appears unlikely that the predisposition to PAH or intrapulmonary angiogenic environment contributes to the lesion development in broilers when compared with layers. It is suggested that the lesion development is associated with increased pulmonary arterial pressure, and that local EPC dysfunction may play a role in the process.

Immunohistochemical and histomorphometric evaluation of vascular distribution in intact canine cranial cruciate ligament.

PubMed

Hayashi, Kei; Bhandal, Jitender; Kim, Sun Young; Rodriguez, Carlos O; Entwistle, Rachel; Naydan, Diane; Kapatkin, Amy; Stover, Susan M

2011-02-01

To (1) describe vascular distribution in the grossly intact canine cranial cruciate ligament (CCL) using immunohistochemical techniques specific to 2 components of blood vessels (factor VIII for endothelial cells, laminin for basement membrane); and (2) compare the vascularity in different areas of interest (craniomedial versus caudolateral bands; core versus epiligamentous regions; and proximal versus middle versus distal portions) in the intact normal canine CCL. In vitro study. Large, mature dogs (n=7) of breeds prone to CCL disease that were euthanatized for nonorthopedic conditions. Intact CCL were collected from fresh canine cadavers free from stifle pathology. CCL tissue was processed for immunohistochemistry and stained for factor VIII and laminin. Vascular density was determined by histomorphometric analysis. Specific vascular staining was sparsely identified throughout the CCL; however, the proximal portion of the CCL appears to have a greater number of vessels than the middle or distal portion of the ligament. The CCL is a hypovascular tissue and its vascular distribution is not homogeneous. © Copyright 2010 by The American College of Veterinary Surgeons.

Impaired revascularization in a mouse model of type 2 diabetes is associated with dysregulation of a complex angiogenic-regulatory network.

PubMed

Schiekofer, Stephan; Galasso, Gennaro; Sato, Kaori; Kraus, Benjamin J; Walsh, Kenneth

2005-08-01

Diabetes is a risk factor for the development of cardiovascular diseases associated with impaired angiogenesis or increased endothelial cell apoptosis. Here it is shown that angiogenic repair of ischemic hindlimbs was impaired in Lepr(db/db) mice, a leptin receptor-deficient model of diabetes, compared with wild-type (WT) C57BL/6 mice, as evaluated by laser Doppler flow and capillary density analyses. To identify molecular targets associated with this disease process, hindlimb cDNA expression profiles were created from adductor muscle of Lepr(db/db) and WT mice before and after hindlimb ischemia using Affymetrix GeneChip Mouse Expression Set microarrays. The expression patterns of numerous angiogenesis-related proteins were altered in Lepr(db/db) versus WT mice after ischemic injury. These transcripts included neuropilin-1, vascular endothelial growth factor-A, placental growth factor, elastin, and matrix metalloproteinases implicated in blood vessel growth and maintenance of vessel wall integrity. These data illustrate that impaired ischemia-induced neovascularization in type 2 diabetes is associated with the dysregulation of a complex angiogenesis-regulatory network.

Effects of low-dose cyclophosphamide with piroxicam on tumour neovascularization in a canine oral malignant melanoma-xenografted mouse model.

PubMed

Choisunirachon, N; Jaroensong, T; Yoshida, K; Saeki, K; Mochizuki, M; Nishimura, R; Sasaki, N; Nakagawa, T

2015-12-01

Low-dose cyclophosphamide (CyLD) has shown promise in the treatment of several cancers; however, the effect of CyLD on canine oral malignant melanoma has never been explored. In this study, we investigated the effects of CyLD with or without piroxicam (Px) on tumour neovascularization and vascular normalization in a canine oral malignant melanoma-xenografted mice model. After treatment with CyLD, Px or a combination of both (CyPx), the growth of the tumour in the treatment groups was significantly suppressed compared to the control group at 30 days of treatment. Proliferation index was also significantly reduced by all treatments, only CyPx significantly lowered microvessel density and vascular endothelial growth factor (VEGF) levels. Additionally, CyLD significantly reduced the proportion of normal vessels and caused an imbalance between VEGF and thrombospondin-1. These results suggested that CyPx has potent anti-angiogenic effects in terms of both the number and quality of blood vessels in xenografted canine oral malignant melanoma. © 2013 John Wiley & Sons Ltd.

In situ assessment of the renal microcirculation in mechanically ventilated rats using sidestream dark-field imaging.

PubMed

Astapenko, D; Jor, O; Lehmann, C; Cerny, V

2015-02-01

For microcirculation research there is a need for baseline data and feasibility protocols describing microcirculation of various organs. The aim of our study was to examine the reliability and reproducibility of sidestream dark-field (SDF) imaging within the renal cortical microcirculation in rats. Renal microcirculation was observed using SDF probe placed on the exposed renal surface via the upper midline laparotomy. Video sequences recorded intermittently in short apneic pauses were analyzed off-line by using AVA 3.0 software (MicroVision Medical, Amsterdam, the Netherlands). Results are expressed as mean (SD) or median (25-75% percentiles). We obtained 60 clear sequences from all recorded analyzable videos from all the animals. The total small vessel and all vessel density (in mm.mm(-2) ) were (28.79 ± 0.40) and (28.95 ± 0.40), respectively. The perfused small and all vessel density were (28.79 ± 0.40) and (28.95 ± 0.40), respectively. The DeBacker Score was (19.14 ± 0.43), the proportion of perfused vessels was 100% (100-100%) and the microvascular flow index was 3.49 (3-3.75). We conclude SDF imaging provides a reliable method to examine the renal microvascular bed in vivo and thus can be used for the study of the renal cortical vascular network in various experimental diseases models and clinical settings. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Expression of SLP-2 gene and CCBE1 are associated with prognosis of rectal cancer.

PubMed

Zhang, L; Liu, F-J

2017-03-01

This study aims to investigate the clinical significance of SLP-2 gene for patients with rectal cancer. To analyze the effect of CCBE1 (Collagen and calcium-binding EGF domain-containing protein 1) on rectal cancer tissue and lymph vessels of para-carcinoma tissue. A total of 50 samples of rectal cancer tissues were enrolled in the experimental group, confirmed by pathological examination. 50 samples of para-carcinoma normal tissues were collected as control group. Protein expression of SLP-2 and CCBE1 was examined with immunohistochemical staining. mRNA expression of SLP-2 was examined with RT-PCR. Lymphatic vessel density (LVD) was evaluated with LYVE-1 immunohistochemical staining. Correlation analysis was performed to assess the relationship between patient survival data and clinical pathological features of rectal cancer. Immunohistochemical staining showed that, compared with the control group, a positive expression rate of SLP-2 in the experimental group was significantly higher (68.0% vs. 24.0%, p<0.05), and mRNA of SLP-2 was also significantly increased (p<0.05). Compared with the control group, protein expression of CCBE1 in the experimental group was significantly higher (p<0.05). Moreover, the expression level of SLP-2 was remarkably associated with TNM classification and lymphatic metastasis. Further analysis demonstrated that a positive expression of CCBE1 was associated with lymphatic metastasis, LVD and Ducks classification, and had a negative correlation with survival rate. Increased expression of SLP-2 promoted the formation of lymph vessels and exacerbated lymphatic metastasis of rectal cancer via up-regulating CCBE1. As a risk factor related to lymphatic metastasis, CCBE1 could be a novel biomarker for diagnosis and prognosis of rectal cancer.

Small and large vessel disease in persons with unrecognized compared to recognized myocardial infarction: The Tromsø Study 2007-2008.

PubMed

Øhrn, Andrea Milde; Schirmer, Henrik; von Hanno, Therese; Mathiesen, Ellisiv B; Arntzen, Kjell Arne; Bertelsen, Geir; Njølstad, Inger; Løchen, Maja-Lisa; Wilsgaard, Tom; Bairey Merz, C Noel; Lindekleiv, Haakon

2018-02-15

Unrecognized myocardial infarction (MI) is a frequent condition with unknown underlying reason. We hypothesized the lack of recognition of MI is related to pathophysiology, specifically differences in underlying small and large vessel disease. 6128 participants were examined with retinal photography, ultrasound of the carotid artery and a 12‑lead electrocardiography (ECG). Small vessel disease was defined as narrower retinal arterioles and/or wider retinal venules measured on retinal photographs. Large vessel disease was defined as carotid artery pathology. We defined unrecognized MI as ECG-evidence of MI without a clinically recognized event. We analyzed the cross-sectional relationship between MI recognition and markers of small and large vessel disease, adjusted for age and sex. Unrecognized MI was present in 502 (8.2%) and recognized MI in 326 (5.3%) of the 6128 participants. Compared to recognized MI, unrecognized MI was associated with small vessel disease indicated by narrower retinal arterioles (OR 1.66, 95% CI 1.05-2.62, highest vs. lowest quartile). Unrecognized MI was less associated with wider retinal venules (OR 0.55, 95% CI 0.35-0.87, lowest vs. highest quartile). Compared to recognized MI, unrecognized MI was less associated with large vessel disease indicated by presence of plaque in the carotid artery (OR for presence of carotid artery plaque in unrecognized MI 0.51, 95% CI 0.37-0.69). No significant sex interaction was present. Unrecognized MI was more associated with small vessel disease and less associated with large vessel disease compared to recognized MI. These findings suggest that the pathophysiology behind unrecognized and recognized MI may differ. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Clinical outcomes in real-world patients with small vessel disease treated with XIENCE V® everolimus-eluting stents: one year results from the XIENCE V® USA condition of approval post-market study.

PubMed

Hermiller, James B; Rutledge, David R; Mao, Vivian W; Zhao, Weiying; Wang, Jin; Gruberg, Luis; Lombardi, William; Sharma, Samin K; Krucoff, Mitchell W

2014-07-01

The purpose of this study was to evaluate the 1-year clinical outcomes of more complex XIENCE V USA real-world patients with small versus nonsmall vessel lesions. Patients with small vessel lesions undergoing coronary stent placement are at higher risk of major adverse cardiac events. Improved safety and efficacy of XIENCE V everolimus eluting stents (EES) have been previously demonstrated in selected low-risk small vessel populations in randomized clinical trials. The XIENCE V USA study was a condition of approval, single-arm study in unselected real-world patients. Baseline and 1-year clinical outcomes were compared between XIENCE V USA patients who received a single 2.5 mm stent (small vessel group, N = 838) and patients implanted with a single >2.5 mm stent (non-small vessel group, N = 2,015). Mean reference vessel diameter was 2.55 ± 0.36 and 3.25 ± 0.46 mm in the small and non-small vessel groups, respectively (P < 0.001). Small vessel group had more females, presented with a higher rate of diabetes, and had more complex lesion characteristics. The definite or probable ST rates analyzed using Kaplan-Meier method were low and not significantly different between the groups at 0.37 and 0.40% for the small and nonsmall vessel group (P = 0.88), respectively. The composite rate of cardiac death or MI was comparable at 4.5% for the small and 5.1% for the non-small vessel 1 groups (P = 0.57). The 1-year target lesion revascularization rate was also comparable in the small vessel group (3.8% vs. 3.0%, P = 0.35). Despite gender difference, higher prevalence of diabetes and more complex lesions in the small vessel groups, the 1-year clinical outcomes were similar in both small and nonsmall vessel groups. These results demonstrate the therapeutic benefit of XIENCE V EES in a real-world all inclusive patient population with small vessel disease. © 2013 Wiley Periodicals, Inc.

Biomechanics of North Atlantic Right Whale Bone: Mandibular Fracture as a Fatal Endpoint for Blunt Vessel-Whale Collision Modeling

DTIC Science & Technology

2007-09-01

Calibration curves for CT number ( Hounsfield unit )s vs. mineral density (g /c c...12 3 Figure 3.4. Calibration curves for CT number ( Hounsfield units ) vs. apparent density (g /c c...named Hounsfield units (HU) after Sir Godfrey Hounsfield . The CT number is K([i- iw]/pw), where K = a magnifying constant, which depends on the make of CT

Identifying Anomalous Behaviour in AIS Data: Loitering and Gaps in Transmission as Indicators of IUU Associated Behaviour.

NASA Astrophysics Data System (ADS)

Ford, J.; Peel, D.; Wilcox, C.; Kroodsma, D.

2016-12-01

Identifying anomalous behaviour associated with Illegal, Unreported and Unregulated (IUU) fishing including supportive activities such as transshipment, is a key step to combating IUU fishing. We use spatial statistical models and Automatic Identification System (AIS) data to identify anomalous activity, specifically various indicators of loitering behaviours (for example, vessels travelling slower than expected, perhaps rendezvousing for transshipment), and gaps in AIS transmissions. Gaps occur for three basic reasons: saturation of the system in locations with high vessel density; poor quality transmissions due to equipment on the vessel or receiver; and intentional disabling of AIS transmitters. Resolving which of these mechanisms is generating gaps in transmissions from a given vessel is a critical task in using AIS to monitor vessels. Moreover, separating saturation and equipment issues from intentional disabling is a useful task in risk identification of IUU associated behaviour. Using this information on loitering behaviour and gaps in transmission, we identify and rank vessels which appear to be acting anomalously, with a focus on identifying potential IUU related activities. This information, combined with other sources of data, could help support enforcement agencies to implement international strategies such as the Port State Measures Agreement. A global list of such vessels and historical evidence of anomalous behaviour, would increase local powers of protection and provide one more step toward transparency within global fisheries.

Tailoring vessel morphology in vivo

NASA Astrophysics Data System (ADS)

Gould, Daniel Joseph

Tissue engineering is a rapidly growing field which seeks to provide alternatives to organ transplantation in order to address the increasing need for transplantable tissues. One huge hurdle in this effort is the provision of thick tissues; this hurdle exists because currently there is no way to provide prevascularized or rapidly vascularizable scaffolds. To design thick, vascularized tissues, scaffolds are needed that can induce vessels which are similar to the microvasculature found in normal tissues. Angiogenic biomaterials are being developed to provide useful scaffolds to address this problem. In this thesis angiogenic and cell signaling and adhesion factors were incorporated into a biomimetic poly(ethylene glycol) (PEG) hydrogel system. The composition of these hydrogels was precisely tuned to induce the formation of differing vessel morphology. To sensitively measure induced microvascular morphology and to compare it to native microvessels in several tissues, this thesis developed an image-based tool for quantification of scale invariant and classical measures of vessel morphology. The tool displayed great utility in the comparison of native vessels and remodeling vessels in normal tissues. To utilize this tool to tune the vessel response in vivo, Flk1::myr-mCherry fluorescently labeled mice were implanted with Platelet Derived Growth Factor-BB (PDGF-BB) and basic Fibroblast Growth Factor (FGF-2) containing PEG-based hydrogels in a modified mouse corneal angiogenesis assay. Resulting vessels were imaged with confocal microscopy, analyzed with the image based tool created in this thesis to compare morphological differences between treatment groups, and used to create a linear relationship between space filling parameters and dose of growth factor release. Morphological parameters of native mouse tissue vessels were then compared to the linear fit to calculate the dose of growth factors needed to induce vessels similar in morphology to native vessels. Resulting induced vessels did match in morphology to the target vessels. Several other covalently bound signals were then analyzed in the assay and resulting morphology of vessels was compared in several studies which further highlighted the utility of the micropocket assay in conjunction with the image based tool for vessel morphological quantification. Finally, an alternative method to provide rapid vasculature to the constructs, which relied on pre-seeded hydrogels encapsulated endothelial cells was also developed and shown to allow anastamosis between induced host vessels and the implanted construct within 48 hours. These results indicate great promise in the rational design of synthetic, bioactive hydrogels, which can be used as a platform to study microvascular induction for regenerative medicine and angiogenesis research. Future applications of this research may help to develop therapeutic strategies to ameliorate human disease by replacing organs or correcting vessel morphology in the case of ischemic diseases and cancer.

Potential effects of shipping on submersed macrophytes in the St. Clair and Detroit Rivers of the Great Lakes

USGS Publications Warehouse

Schloesser, Donald W.; Manny, Bruce A.

1989-01-01

An extensive survey of submersed macrophytes in the St. Clair and Detroit rivers revealed statistically significant differences in the composition and density of macrophyte beds in shipping channels (used by commercial vessels passing between Lakes Huron and Erie) and non-shipping channels. Of nine common macrophyte taxa, four (Characae, Potamogeton richardsonii, Potamogeton spp. narrow-leaf forms, and Najas flexilis) were found more frequently and three (Myriophyllum spicatum, Elodea canadensis, and Heteranthera dubia) less frequently in shipping than in non-shipping channels. In general, macrophyte beds were less dense in shipping channels than in non-shipping channels. We postulate that disruption of the prevailing unidirectional current patterns and erosion of suitable substrate or breakage of plant stems by passing vessels caused the observed differences in the composition and density of macrophyte beds in shipping and non-shipping channels in the St. Clair and Detroit rivers.

Measurement of toroidal vessel eddy current during plasma disruption on J-TEXT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, L. J.; Yu, K. X.; Zhang, M., E-mail: zhangming@hust.edu.cn

2016-01-15

In this paper, we have employed a thin, printed circuit board eddy current array in order to determine the radial distribution of the azimuthal component of the eddy current density at the surface of a steel plate. The eddy current in the steel plate can be calculated by analytical methods under the simplifying assumptions that the steel plate is infinitely large and the exciting current is of uniform distribution. The measurement on the steel plate shows that this method has high spatial resolution. Then, we extended this methodology to a toroidal geometry with the objective of determining the poloidal distributionmore » of the toroidal component of the eddy current density associated with plasma disruption in a fusion reactor called J-TEXT. The preliminary measured result is consistent with the analysis and calculation results on the J-TEXT vacuum vessel.« less

Tokamak with mechanical compression of toroidal magnetic field

DOEpatents

Ohkawa, Tihiro

1981-01-01

A tokamak apparatus includes a pressure vessel for defining a reservoir and confining liquid therein. A collapsible toroidal liner disposed within the pressure vessel defines a toroidal space within the liner. Liquid metal fills the reservoir outside said liner. A toroidal magnetic field is developed within the toroidal space about the major axis thereof. A toroidal plasma is developed within the toroidal space about the major axis thereof. Pressure is applied to the liquid metal to collapse the liner and reduce the volume of the toroidal space, thereby increasing the toroidal magnetic flux density therein.

Storage of H.sub.2 by absorption and/or mixture within a fluid medium

DOEpatents

Berry, Gene David; Aceves, Salvador Martin

2007-03-20

For the first time, a hydrogen storage method, apparatus and system having a fluid mixture is provided. At predetermined pressures and/or temperatures within a contained substantially fixed volume, the fluid mixture can store a high density of hydrogen molecules, wherein a predetermined phase of the fluid mixture is capable of being withdrawn from the substantially fixed volume for use as a vehicle fuel or energy storage having reduced and/or eliminated evaporative losses, especially where storage weight, vessel cost, vessel shape, safety, and energy efficiency are beneficial.

Treatment with eCG decreases the vascular density and increases the glandular density of the bovine uterus.

PubMed

Mona e Pinto, J; Pavanelo, V; Alves de Fátima, L; Medeiros de Carvalho Sousa, L M; Pacheco Mendes, G; Machado Ferreira, R; Ayres, H; Sampaio Baruselli, P; Palma Rennó, F; de Carvallo Papa, P

2014-06-01

The uterus plays an essential role in mammalian reproduction and is a target of several hormonal protocols used to improve fertility in cattle. Many studies highlighted the importance of eCG treatment following fixed-time artificial insemination in improving follicular growth, ovulation and pregnancy rates in cattle. Moreover, eCG has been implicated in angiogenesis, leading to important changes in uterine blood flow and vascularisation. However, there is still a lack of information regarding the specific alterations induced by eCG upon glandular and vascular characteristics of bovine uterus. To investigate the influence of eCG on: uterine thickness and area; uterine artery diameter and area; uterine vascular and gland density; and the expression of the VEGFA-system, the uteri of crossbred beef cows were collected. All cows were submitted to follicular wave emergence synchronization. On day four of protocol, cows submitted to superovulation (n = 6) received 2000 IU eCG, on day eight, after expected follicular deviation, cows submitted to stimulatory treatment (n = 5) received 400 IU eCG. Control cows (n = 5) did not receive eCG. On day five po cows were subjected to ultrassonographic evaluation and slaughtered for uterine tissue sampling on day six po. Uterine vessels and glands were quantified by the counting point stereological method. The VEGFA-system was localized in different cellular types, showing no qualitative or quantitative differences in the site of expression or the intensity of the positive signal among the groups. Vascular density was decreased in the endometrium of stimulated and myometrium of superovulated cows compared with the control ones, which showed higher vascular density in the myometrium and endometrium of the ipsilateral uterine horn. The uterine gland density was higher in superovulated compared with stimulated and control cows. Thus, we can infer that stimulatory or superovulatory treatments with eCG influence the vascular density in the endometrium and myometrium in cattle. © 2014 Blackwell Verlag GmbH.

Superior long term outcome associated with native vessel versus graft vessel PCI following secondary PCI in patients with prior CABG.

PubMed

Mavroudis, Chrysostomos A; Kotecha, Tushar; Chehab, Omar; Hudson, Jonathan; Rakhit, Roby D

2017-02-01

Secondary percutaneous coronary intervention (PCI) in patients with prior coronary artery bypass graft surgery is increasingly common. Graft vessel PCI has higher rates of adverse events compared with native coronary vessel PCI. To investigate the clinical outcomes of patients with prior CABG who underwent secondary PCI of either a graft vessel (GV), a native coronary vessel (NV) or both graft and native (NG) vessels. 220 patients (84% male) who underwent PCI in our institution to either GV (n=89), NV (n=103) or both GV and NV (NG group) (n=28) were studied. The study population underwent 378 procedures (GV group; n=126, NV group; n=164 and NG group; n=88). Median follow up was for 36months [range 2-75months]. Target vessel revascularisation (TVR) occurred in 12.5% of the GV group and 3.6% in the NV group [p=0.0004], and was predominantly due to in-stent restenosis. Patients who had PCI due to TVR were more likely to suffer from diabetes and peripheral vascular disease. History of chronic renal failure was associated with higher risk (HR 2.21, p=0.005) whereas preserved left ventricular ejection fraction (LVEF) with lower risk (HR 0.17, p=0.0007) of death. The median survival (interval between CABG and end of follow-up period) was lower in the GV compared with the NV group (315 vs 372months p=0.005). This registry demonstrates inferior long term outcome for patients undergoing secondary PCI of GV versus NV. Where possible, a strategy of NV rather than GV target PCI should be considered in patients with prior CABG. Secondary PCI in patients with prior CABG surgery is increasingly common. Graft vessel PCI has inferior outcomes with high rates of restenosis and occlusion compared with native coronary vessel PCI. We studied the clinical outcomes of 220 patients with prior CABG who underwent secondary PCI to either a graft vessel (GV), a native coronary vessel (NV) or both graft and native (NG) vessels. Target vessel revascularisation was 5 times higher in the GV compared with the NV group. History of CRF and impaired left ventricular function were associated with higher risk of death. We also found that the median survival (interval between CABG and end of follow-up period) was better in the NV group compared with GV group. This registry study demonstrates inferior long term outcome for patients undergoing secondary PCI of GV. A strategy of NV rather than GV target PCI should be considered in patients with prior CABG. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Bim expression in endothelial cells and pericytes is essential for regression of the fetal ocular vasculature.

PubMed

Wang, Shoujian; Zaitoun, Ismail S; Johnson, Ryan P; Jamali, Nasim; Gurel, Zafer; Wintheiser, Catherine M; Strasser, Andreas; Lindner, Volkhard; Sheibani, Nader; Sorenson, Christine M

2017-01-01

Apoptosis plays a central role in developmental and pathological angiogenesis and vessel regression. Bim is a pro-apoptotic Bcl-2 family member that plays a prominent role in both developmental and pathological ocular vessel regression, and neovascularization. Endothelial cells (EC) and pericytes (PC) each play unique roles during vascular development, maintenance and regression. We recently showed that germline deletion of Bim results in persistent hyaloid vasculature, increased retinal vascular density and prevents retinal vessel regression in response to hyperoxia. To determine whether retinal vascular regression is attributable to Bim expression in EC or PC we generated mice carrying a conditional Bim allele (BimFlox/Flox) and VE-cadherin-cre (BimEC mice) or Pdgfrb-cre (BimPC mice). BimEC and BimPC mice demonstrated attenuated hyaloid vessel regression and postnatal retinal vascular remodeling. We also observed decreased retinal vascular apoptosis and proliferation. Unlike global Bim -/- mice, mice conditionally lacking Bim in EC or PC underwent hyperoxia-mediated vessel obliteration and subsequent retinal neovascularization during oxygen-induced ischemic retinopathy similar to control littermates. Thus, understanding the cell autonomous role Bim plays in the retinal vascular homeostasis will give us new insight into how to modulate pathological retinal neovascularization and vessel regression to preserve vision.

Control system for a small fission reactor

DOEpatents

Burelbach, James P.; Kann, William J.; Saiveau, James G.

1986-01-01

A system for controlling the reactivity of a small fission reactor includes an elongated, flexible hollow tube in the general form of a helical coiled spring axially positioned around and outside of the reactor vessel in an annular space between the reactor vessel and a surrounding cylindrical-shaped neutron reflector. A neutron absorbing material is provided within the hollow tube with the rate of the reaction controlled by the extension and compression of the hollow tube, e.g., extension of the tube increases reactivity while its compression reduces reactivity, in varying the amount of neutron absorbing material disposed between the reactor vessel and the neutron reflector. Conventional mechanical displacement means may be employed to control the coil density of the hollow tube as desired. In another embodiment, a plurality of flexible hollow tubes each containing a neutron absorber are positioned adjacent to one another in spaced relation around the periphery of the reactor vessel and inside the outer neutron reflector with reactivity controlled by the extension and compression of all or some of the coiled hollow tubes. Yet another embodiment of the invention envisions the neutron reflector in the form of an expandable coil spring positioned in an annular space between the reactor vessel and an outer neutron absorbing structure for controlling the neutron flux reflected back into the reactor vessel.

Scleral electrocautery and its effects on choroid vessels: implications for subretinal fluid drainage during scleral buckling surgery.

PubMed

Roybal, C Nathaniel; Tsui, Irena; Sanfilippo, Christian; Hubschman, Jean-Pierre

2013-01-01

External drainage of subretinal fluid as part of a scleral buckling procedure rapidly restores the retinal pigment epithelium-neural retina interface in rhegmatogenous retinal detachments but carries the inherent risk of subretinal hemorrhage and retinal incarceration. The authors investigated variations to the technique to reduce the chance of subretinal hemorrhage originating from the choroid. A novel method for needle drainage using electrocautery of the sclerochoroidal layers before puncture was employed. The effect of 0% to 50% scleral electrocautery in a porcine model was investigated. A significant decrease in choroidal vessel diameter and choroidal vessel density at 40% electrocautery was demonstrated. Electrocautery without scleral cut-down before external drainage of subretinal fluid likely decreases the chance of subretinal hemorrhage by decreasing choroidal vascularity. Copyright 2013, SLACK Incorporated.

Accuracy of Estimation of Graft Size for Living-Related Liver Transplantation: First Results of a Semi-Automated Interactive Software for CT-Volumetry

PubMed Central

Mokry, Theresa; Bellemann, Nadine; Müller, Dirk; Lorenzo Bermejo, Justo; Klauß, Miriam; Stampfl, Ulrike; Radeleff, Boris; Schemmer, Peter; Kauczor, Hans-Ulrich; Sommer, Christof-Matthias

2014-01-01

Objectives To evaluate accuracy of estimated graft size for living-related liver transplantation using a semi-automated interactive software for CT-volumetry. Materials and Methods Sixteen donors for living-related liver transplantation (11 male; mean age: 38.2±9.6 years) underwent contrast-enhanced CT prior to graft removal. CT-volumetry was performed using a semi-automated interactive software (P), and compared with a manual commercial software (TR). For P, liver volumes were provided either with or without vessels. For TR, liver volumes were provided always with vessels. Intraoperative weight served as reference standard. Major study goals included analyses of volumes using absolute numbers, linear regression analyses and inter-observer agreements. Minor study goals included the description of the software workflow: degree of manual correction, speed for completion, and overall intuitiveness using five-point Likert scales: 1–markedly lower/faster/higher for P compared with TR, 2–slightly lower/faster/higher for P compared with TR, 3–identical for P and TR, 4–slightly lower/faster/higher for TR compared with P, and 5–markedly lower/faster/higher for TR compared with P. Results Liver segments II/III, II–IV and V–VIII served in 6, 3, and 7 donors as transplanted liver segments. Volumes were 642.9±368.8 ml for TR with vessels, 623.8±349.1 ml for P with vessels, and 605.2±345.8 ml for P without vessels (P<0.01). Regression equations between intraoperative weights and volumes were y = 0.94x+30.1 (R2 = 0.92; P<0.001) for TR with vessels, y = 1.00x+12.0 (R2 = 0.92; P<0.001) for P with vessels, and y = 1.01x+28.0 (R2 = 0.92; P<0.001) for P without vessels. Inter-observer agreement showed a bias of 1.8 ml for TR with vessels, 5.4 ml for P with vessels, and 4.6 ml for P without vessels. For the degree of manual correction, speed for completion and overall intuitiveness, scale values were 2.6±0.8, 2.4±0.5 and 2. Conclusions CT-volumetry performed with P can predict accurately graft size for living-related liver transplantation while improving workflow compared with TR. PMID:25330198

Improved specific energy Ni-H2 cell

NASA Astrophysics Data System (ADS)

Miller, L. E.

1985-12-01

Significant improvements in specific energy for Ni-H2 battery cells have been and will be achieved. Current flight cell designs in operation on multiple satellites have achieved a specific energy of 52 Whr/Kg (this value may be compared to 45 Whr/Kg for advanced, light-weight Ni-Cd space cells). Battery cells operating at increased pressures (61 atm/900 psi) have been manufactured and successfully tested demonstrating a specific energy of 70 Whr/Kg. Further optimization of electrode substrate, pressure vessel wall thickness and cell terminal/conductor assembly designs will permit achievement of specific energies between 75-80 Whr/Kg. Energy density (outline volume) will be improved from 49 Whr/L to 79 Whr/L.

Heterozygous Deficiency of PHD2 Restores Tumor Oxygenation and Inhibits Metastasis via Endothelial Normalization

PubMed Central

Loges, Sonja; Schmidt, Thomas; Jonckx, Bart; Tian, Ya-Min; Lanahan, Anthony A.; Pollard, Patrick; de Almodovar, Carmen Ruiz; De Smet, Frederik; Vinckier, Stefan; Aragonés, Julián; Debackere, Koen; Luttun, Aernout; Wyns, Sabine; Jordan, Benedicte; Pisacane, Alberto; Gallez, Bernard; Lampugnani, Maria Grazia; Dejana, Elisabetta; Simons, Michael; Ratcliffe, Peter; Maxwell, Patrick; Carmeliet, Peter

2014-01-01

SUMMARY A key function of blood vessels, to supply oxygen, is impaired in tumors because of abnormalities in their endothelial lining. PHD proteins serve as oxygen sensors and may regulate oxygen delivery. We therefore studied the role of endothelial PHD2 in vessel shaping by implanting tumors in PHD2+/− mice. Haplodeficiency of PHD2 did not affect tumor vessel density or lumen size, but normalized the endothelial lining and vessel maturation. This resulted in improved tumor perfusion and oxygenation and inhibited tumor cell invasion, intravasation, and metastasis. Haplodeficiency of PHD2 redirected the specification of endothelial tip cells to a more quiescent cell type, lacking filopodia and arrayed in a phalanx formation. This transition relied on HIF-driven upregulation of (soluble) VEGFR-1 and VE-cadherin. Thus, decreased activity of an oxygen sensor in hypoxic conditions prompts endothelial cells to readjust their shape and phenotype to restore oxygen supply. Inhibition of PHD2 may offer alternative therapeutic opportunities for anticancer therapy. PMID:19217150

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogami, M; Kulkarni, R; Wang, H

We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collateralsmore » and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing. (laser biophotonics)« less

The embryonic mouse hindbrain as a qualitative and quantitative model for studying the molecular and cellular mechanisms of angiogenesis.

PubMed

Fantin, Alessandro; Vieira, Joaquim M; Plein, Alice; Maden, Charlotte H; Ruhrberg, Christiana

2013-02-01

The mouse embryo hindbrain is a robust and adaptable model for studying sprouting angiogenesis. It permits the spatiotemporal analysis of organ vascularization in normal mice and in mouse strains with genetic mutations that result in late embryonic or perinatal lethality. Unlike postnatal models such as retinal angiogenesis or Matrigel implants, there is no requirement for the breeding of conditional knockout mice. The unique architecture of the hindbrain vasculature allows whole-mount immunolabeling of blood vessels and high-resolution imaging, as well as easy quantification of angiogenic sprouting, network density and vessel caliber. The hindbrain model also permits the visualization of ligand binding to blood vessels in situ and the analysis of blood vessel growth within a natural multicellular microenvironment in which endothelial cells (ECs) interact with non-ECs to refine the 3D organ architecture. The entire procedure, from embryo isolation to imaging and through to results analysis, takes approximately 4 d.

Vascular responses to radiotherapy and androgen-deprivation therapy in experimental prostate cancer

PubMed Central

2012-01-01

Background Radiotherapy (RT) and androgen-deprivation therapy (ADT) are standard treatments for advanced prostate cancer (PC). Tumor vascularization is recognized as an important physiological feature likely to impact on both RT and ADT response, and this study therefore aimed to characterize the vascular responses to RT and ADT in experimental PC. Methods Using mice implanted with CWR22 PC xenografts, vascular responses to RT and ADT by castration were visualized in vivo by DCE MRI, before contrast-enhancement curves were analyzed both semi-quantitatively and by pharmacokinetic modeling. Extracted image parameters were correlated to the results from ex vivo quantitative fluorescent immunohistochemical analysis (qIHC) of tumor vascularization (9 F1), perfusion (Hoechst 33342), and hypoxia (pimonidazole), performed on tissue sections made from tumors excised directly after DCE MRI. Results Compared to untreated (Ctrl) tumors, an improved and highly functional vascularization was detected in androgen-deprived (AD) tumors, reflected by increases in DCE MRI parameters and by increased number of vessels (VN), vessel density ( VD), and vessel area fraction ( VF) from qIHC. Although total hypoxic fractions ( HF) did not change, estimated acute hypoxia scores ( AHS) – the proportion of hypoxia staining within 50 μm from perfusion staining – were increased in AD tumors compared to in Ctrl tumors. Five to six months after ADT renewed castration-resistant (CR) tumor growth appeared with an even further enhanced tumor vascularization. Compared to the large vascular changes induced by ADT, RT induced minor vascular changes. Correlating DCE MRI and qIHC parameters unveiled the semi-quantitative parameters area under curve ( AUC) from initial time-points to strongly correlate with VD and VF, whereas estimation of vessel size ( VS) by DCE MRI required pharmacokinetic modeling. HF was not correlated to any DCE MRI parameter, however, AHS may be estimated after pharmacokinetic modeling. Interestingly, such modeling also detected tumor necrosis very strongly. Conclusions DCE MRI reliably allows non-invasive assessment of tumors’ vascular function. The findings of increased tumor vascularization after ADT encourage further studies into whether these changes are beneficial for combined RT, or if treatment with anti-angiogenic therapy may be a strategy to improve the therapeutic efficacy of ADT in advanced PC. PMID:22621752

Variability in radial sap flux density patterns and sapwood area among seven co-occurring temperate broad-leaved tree species.

PubMed

Gebauer, Tobias; Horna, Viviana; Leuschner, Christoph

2008-12-01

Forest transpiration estimates are frequently based on xylem sap flux measurements in the outer sections of the hydro-active stem sapwood. We used Granier's constant-heating technique with heating probes at various xylem depths to analyze radial patterns of sap flux density in the sapwood of seven broad-leaved tree species differing in wood density and xylem structure. Study aims were to (1) compare radial sap flux density profiles between diffuse- and ring-porous trees and (2) analyze the relationship between hydro-active sapwood area and stem diameter. In all investigated species except the diffuse-porous beech (Fagus sylvatica L.) and ring-porous ash (Fraxinus excelsior L.), sap flux density peaked at a depth of 1 to 4 cm beneath the cambium, revealing a hump-shaped curve with species-specific slopes. Beech and ash reached maximum sap flux densities immediately beneath the cambium in the youngest annual growth rings. Experiments with dyes showed that the hydro-active sapwood occupied 70 to 90% of the stem cross-sectional area in mature trees of diffuse-porous species, whereas it occupied only about 21% in ring-porous ash. Dendrochronological analyses indicated that vessels in the older sapwood may remain functional for 100 years or more in diffuse-porous species and for up to 27 years in ring-porous ash. We conclude that radial sap flux density patterns are largely dependent on tree species, which may introduce serious bias in sap-flux-derived forest transpiration estimates, if non-specific sap flux profiles are assumed.

Hairy root culture in a liquid-dispersed bioreactor: characterization of spatial heterogeneity.

PubMed

Williams, G R; Doran, P M

2000-01-01

A liquid-dispersed reactor equipped with a vertical mesh cylinder for inoculum support was developed for culture of Atropa belladonna hairy roots. The working volume of the culture vessel was 4.4 L with an aspect ratio of 1.7. Medium was dispersed as a spray onto the top of the root bed, and the roots grew radially outward from the central mesh cylinder to the vessel wall. Significant benefits in terms of liquid drainage and reduced interstitial liquid holdup were obtained using a vertical rather than horizontal support structure for the biomass and by operating the reactor with cocurrent air and liquid flow. With root growth, a pattern of spatial heterogeneity developed in the vessel. Higher local biomass densities, lower volumes of interstitial liquid, lower sugar concentrations, and higher root atropine contents were found in the upper sections of the root bed compared with the lower sections, suggesting a greater level of metabolic activity toward the top of the reactor. Although gas-liquid oxygen transfer to the spray droplets was very rapid, there was evidence of significant oxygen limitations in the reactor. Substantial volumes of non-free-draining interstitial liquid accumulated in the root bed. Roots near the bottom of the vessel trapped up to 3-4 times their own weight in liquid, thus eliminating the advantages of improved contact with the gas phase offered by liquid-dispersed culture systems. Local nutrient and product concentrations in the non-free-draining liquid were significantly different from those in the bulk medium, indicating poor liquid mixing within the root bed. Oxygen enrichment of the gas phase improved neither growth nor atropine production, highlighting the greater importance of liquid-solid compared with gas-liquid oxygen transfer resistance. The absence of mechanical or pneumatic agitation and the tendency of the root bed to accumulate liquid and impede drainage were identified as the major limitations to reactor performance. Improved reactor operating strategies and selection or development of root lines offering minimal resistance to liquid flow and low liquid retention characteristics are possible solutions to these problems.

Fetal and neonatal iron deficiency but not copper deficiency increases vascular complexity in the developing rat brain

PubMed Central

Bastian, Thomas W.; Santarriaga, Stephanie; Nguyen, Thu An; Prohaska, Joseph R.; Georgieff, Michael K.; Anderson, Grant W.

2015-01-01

Objectives Anemia caused by nutritional deficiencies, such as iron and copper deficiencies, is a global health problem. Iron and copper deficiencies have their most profound effect on the developing fetus/infant, leading to brain development deficits and poor cognitive outcomes. Tissue iron depletion or chronic anemia can induce cellular hypoxic signaling. In mice, chronic hypoxia induces a compensatory increase in brain blood vessel outgrowth. We hypothesized that developmental anemia, due to iron or copper deficiencies, induces angiogenesis/vasculogenesis in the neonatal brain. Methods To test our hypothesis, three independent experiments were performed where pregnant rats were fed iron- or copper-deficient diets from gestational day 2 through mid-lactation. Effects on the neonatal brain vasculature were determined using qPCR to assess mRNA levels of angiogenesis/vasculogenesis-associated genes and GLUT1 immunohistochemistry (IHC) to assess brain blood vessel density and complexity. Results Iron deficiency, but not copper deficiency, increased mRNA expression of brain endothelial cell- and angiogenesis/vasculogenesis-associated genes (i.e. Glut1, Vwf, Vegfa, Ang2, Cxcl12, and Flk1) in the neonatal brain, suggesting increased cerebrovascular density. Iron deficiency also increased hippocampal and cerebral cortical blood vessel branching by 62% and 78%, respectively. Discussion This study demonstrates increased blood vessel complexity in the neonatal iron-deficient brain, which is likely due to elevated angiogenic/vasculogenic signaling. At least initially, this is probably an adaptive response to maintain metabolic substrate homeostasis in the developing iron-deficient brain. However, this may also contribute to long-term neurodevelopmental deficits. PMID:26177275

The Influence of Dome Size, Parent Vessel Angle, and Coil Packing Density on Coil Embolization Treatment in Cerebral Aneurysms

NASA Astrophysics Data System (ADS)

Frakes, David H.; Indahlastari, Aprinda; Ryan, Justin; Babiker, M. Haithem; Nair, Priya; Parthas, Varsha

2013-11-01

Intracranial aneurysms (ICAs) are dilated cerebral blood vessels. Treating ICAs effectively prior rupture is crucial since their association with 45% mortality rate. Embolic coiling is the most effective ICA treatment. Series of embolic coils are deployed into the aneurysm with the intent of reaching a sufficient packing density (PD) to help seal off the ICA from circulation. While coiling is effective, treatment failures have been associated with basilar tip aneurysms (BTAs), perhaps because of their geometry. The aim of this study was to examine the effect of dome size, parent vessel (PV) angle, and PD on intraaneurysmal (IA) velocity, crossneck (CN) flow and low wall shear stress (WSS) area using simulations and experiments in idealized BTA models. IA velocity and CN flow decreased after coiling, while low WSS area increased. With increasing PD, IA velocity and CN flow were further reduced, but low WSS area had a minimal change. Coil PD had the greatest impact on post-treatment flow while dome size had a greater impact than PV angle. Overall, the role of aneurysmal geometries may vary depending on treatment goal and timing e.g., high coil PD may reduce IA velocity more effectively during early aneurysmal growth when the dome size is small. Funded by the American Heart Association.

Bim is Responsible for the Inherent Sensitivity of the Developing Retinal Vasculature to Hyperoxia

PubMed Central

Wang, Shoujian; Park, SunYoung; Fei, Ping; Sorenson, Christine M.

2010-01-01

Apoptosis plays an important role in development and remodeling of vasculature during organogenesis. Coordinated branching and remodeling of the retinal vascular tree is essential for normal retinal function. Bcl-2 family members, such as bim can not only influence apoptosis, but also cell adhesive and migratory properties essential during vascular development. Here we examined the impact of bim deficiency on postnatal retinal vascularization, as well as retinal neovascularization during oxygen-induced ischemic retinopathy (OIR) and laser-induced choroidal neovascularization. Loss of bim expression was associated with increased retinal vascular density in mature animals. This was mainly attributed to increased numbers of pericytes and endothelial cells. However, the initial spread of the superficial layer of retinal vasculature and, the appearance and density of the tip cells were similar in bim +/+ and bim -/- mice. In addition, hyaloid vessel regression was attenuated in the absence of bim. Furthermore, in the absence of bim retinal vessel obliteration and neovascularization did not occur during OIR. Instead, normal inner retinal vascularization proceeded independent of changes in oxygen levels. In contrast, choroidal neovascularization occurred equally well in bim +/+ and bim -/- mice. Together our data suggest bim expression may be responsible for the inherent sensitivity of the developing retinal vasculature to changes in oxygen levels, and promotes vessel obliteration in response to hyperoxia. PMID:21047504

Angiogenesis in arthritis: role in disease pathogenesis and as a potential therapeutic target.

PubMed

Paleolog, E M; Miotla, J M

1998-01-01

Rheumatoid arthritis (RA) is a chronic destructive musculo-skeletal disorder, associated with thickening of the synovial membrane lining the joints, inflammation and hyperproliferation of synovial cells, as well as a pro-inflammatory cytokine cascade, leukocyte infiltration, and tissue damage and bone resorption. An early event in RA is an alteration in blood vessel density and prominent neovascularisation. The hyperplasia of the synovium necessitates a compensatory increase in the number of blood vessels to nourish and oxygenate the tissue. However, angiogenesis may not keep pace with synovial proliferation, leading to regions of hypoperfusion and hypoxia. VEGF, a potent endothelial cell mitogen, is expressed in RA synovium and elevated in the serum of RA patients. We have reported that dissociated RA synovial membrane cells spontaneously secrete VEGF, and that release of VEGF by these cells is upregulated by cytokines and hypoxia. In a murine model of RA, VEGF is released from synovial cells isolated from the knees of arthritic but not healthy mice, and the extent of VEGF production correlates with the severity of arthritis. VEGF thus appears to play a key role in mediating alterations in synovial vessel density in arthritis. As a consequence, RA may be a potential target for anti-angiogenic therapy, and targeting VEGF may prove to be especially beneficial.

CFD Analyses of Air-Ingress Accident for VHTRs

NASA Astrophysics Data System (ADS)

Ham, Tae Kyu

The Very High Temperature Reactor (VHTR) is one of six proposed Generation-IV concepts for the next generation of nuclear powered plants. The VHTR is advantageous because it is able to operate at very high temperatures, thus producing highly efficient electrical generation and hydrogen production. A critical safety event of the VHTR is a loss-of-coolant accident. This accident is initiated, in its worst-case scenario, by a double-ended guillotine break of the cross vessel that connects the reactor vessel and the power conversion unit. Following the depressurization process, the air (i.e., the air and helium mixture) in the reactor cavity could enter the reactor core causing an air-ingress event. In the event of air-ingress into the reactor core, the high-temperature in-core graphite structures will chemically react with the air and could lose their structural integrity. We designed a 1/8th scaled-down test facility to develop an experimental database for studying the mechanisms involved in the air-ingress phenomenon. The current research focuses on the analysis of the air-ingress phenomenon using the computational fluid dynamics (CFD) tool ANSYS FLUENT for better understanding of the air-ingress phenomenon. The anticipated key steps in the air-ingress scenario for guillotine break of VHTR cross vessel are: 1) depressurization; 2) density-driven stratified flow; 3) local hot plenum natural circulation; 4) diffusion into the reactor core; and 5) global natural circulation. However, the OSU air-ingress test facility covers the time from depressurization to local hot plenum natural circulation. Prior to beginning the CFD simulations for the OSU air-ingress test facility, benchmark studies for the mechanisms which are related to the air-ingress accident, were performed to decide the appropriate physical models for the accident analysis. In addition, preliminary experiments were performed with a simplified 1/30th scaled down acrylic set-up to understand the air-ingress mechanism and to utilize the CFD simulation in the analysis of the phenomenon. Previous air-ingress studies simulated the depressurization process using simple assumptions or 1-D system code results. However, recent studies found flow oscillations near the end of the depressurization which could influence the next stage of the air-ingress accident. Therefore, CFD simulations were performed to examine the air-ingress mechanisms from the depressurization through the establishment of local natural circulation initiate. In addition to the double-guillotine break scenario, there are other scenarios that can lead to an air-ingress event such as a partial break were in the cross vessel with various break locations, orientations, and shapes. These additional situations were also investigated. The simulation results for the OSU test facility showed that the discharged helium coolant from a reactor vessel during the depressurization process will be mixed with the air in the containment. This process makes the density of the gas mixture in the containment lower and the density-driven air-ingress flow slower because the density-driven flow is established by the density difference of the gas species between the reactor vessel and the containment. In addition, for the simulations with various initial and boundary conditions, the simulation results showed that the total accumulated air in the containment collapsed within 10% standard deviation by: 1. multiplying the density ratio and viscosity ratio of the gas species between the containment and the reactor vessel and 2. multiplying the ratio of the air mole fraction and gas temperature to the reference value. By replacing the gas mixture in the reactor cavity with a gas heavier than the air, the air-ingress speed slowed down. Based on the understanding of the air-ingress phenomena for the GT-MHR air-ingress scenario, several mitigation measures of air-ingress accident are proposed. The CFD results are utilized to plan experimental strategy and apparatus installation to obtain the best results when conducting an experiment. The validation of the generated CFD solutions will be performed with the OSU air-ingress experimental results. (Abstract shortened by UMI.).

Differential Mechanisms Associated with Vascular Disrupting Action of Electrochemotherapy: Intravital Microscopy on the Level of Single Normal and Tumor Blood Vessels

PubMed Central

Markelc, Bostjan; Sersa, Gregor; Cemazar, Maja

2013-01-01

Electropermeabilization/electroporation (EP) provides a tool for the introduction of molecules into cells and tissues. In electrochemotherapy (ECT), cytotoxic drugs are introduced into cells in tumors, and nucleic acids are introduced into cells in gene electrotransfer. The normal and tumor tissue blood flow modifying effects of EP and the vascular disrupting effect of ECT in tumors have already been determined. However, differential effects between normal vs. tumor vessels, to ensure safety in the clinical application of ECT, have not been determined yet. Therefore, the aim of our study was to determine the effects of EP and ECT with bleomycin on the HT-29 human colon carcinoma tumor model and its surrounding blood vessels. The response of blood vessels to EP and ECT was monitored in real time, directly at the single blood vessel level, by in vivo optical imaging in a dorsal window chamber in SCID mice with 70 kDa fluorescently labeled dextrans. The response of tumor blood vessels to EP and ECT started to differ within the first hour. Both therapies induced a vascular lock, decreased functional vascular density (FVD) and increased the diameter of functional blood vessels within the tumor. The effects were more pronounced for ECT, which destroyed the tumor blood vessels within 24 h. Although the vasculature surrounding the tumor was affected by EP and ECT, it remained functional. The study confirms the current model of tumor blood flow modifying effects of EP and provides conclusive evidence that ECT is a vascular disrupting therapy with a specific effect on the tumor blood vessels. PMID:23555705

Microvascular dysfunction in the immediate aftermath of chronic total coronary occlusion recanalization.

PubMed

Ladwiniec, Andrew; Cunnington, Michael S; Rossington, Jennifer; Thackray, Simon; Alamgir, Farquad; Hoye, Angela

2016-05-01

The aim of this study was to compare microvascular resistance under both baseline and hyperemic conditions immediately after percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) with an unobstructed reference vessel in the same patient Microvascular dysfunction has been reported to be prevalent immediately after CTO PCI. However, previous studies have not made comparison with a reference vessel. Patients with a CTO may have global microvascular and/or endothelial dysfunction, making comparison with established normal values misleading. After successful CTO PCI in 21 consecutive patients, coronary pressure and flow velocity were measured at baseline and hyperemia in distal segments of the CTO/target vessel and an unobstructed reference vessel. Hemodynamics including hyperemic microvascular resistance (HMR), basal microvascular resistance (BMR), and instantaneous minimal microvascular resistance at baseline and hyperemia were calculated and compared between reference and target/CTO vessels. After CTO PCI, BMR was reduced in the target/CTO vessel compared with the reference vessel: 3.58 mm Hg/cm/s vs 4.94 mm Hg/cm/s, difference -1.36 mm Hg/cm/s (-2.33 to -0.39, p = 0.008). We did not detect a difference in HMR: 1.82 mm Hg/cm/s vs 2.01 mm Hg/cm/s, difference -0.20 (-0.78 to 0.39, p = 0.49). Instantaneous minimal microvascular resistance correlated strongly with the length of stented segment at baseline (r = 0.63, p = 0.005) and hyperemia (r = 0.68, p = 0.002). BMR is reduced in a recanalized CTO in the immediate aftermath of PCI compared to an unobstructed reference vessel; however, HMR appears to be preserved. A longer stented segment is associated with increased microvascular resistance. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The effect of an apolipoprotein A-I-containing high-density lipoprotein-mimetic particle (CER-001) on carotid artery wall thickness in patients with homozygous familial hypercholesterolemia: The Modifying Orphan Disease Evaluation (MODE) study.

PubMed

Hovingh, G Kees; Smits, Loek P; Stefanutti, Claudia; Soran, Handrean; Kwok, See; de Graaf, Jacqueline; Gaudet, Daniel; Keyserling, Constance H; Klepp, Heather; Frick, Jennifer; Paolini, John F; Dasseux, Jean-Louis; Kastelein, John J P; Stroes, Erik S

2015-05-01

Patients with homozygous familial hypercholesterolemia (HoFH) are at extremely elevated risk for early cardiovascular disease because of exposure to elevated low-density lipoprotein cholesterol (LDL-C) plasma levels from birth. Lowering LDL-C by statin therapy is the cornerstone for cardiovascular disease prevention, but the residual risk in HoFH remains high, emphasizing the need for additional therapies. In the present study, we evaluated the effect of serial infusions with CER-001, a recombinant human apolipoprotein A-I (apoA-I)-containing high-density lipoprotein-mimetic particle, on carotid artery wall dimensions in patients with HoFH. Twenty-three patients (mean age 39.4 ± 13.5 years, mean LDL-C 214.2 ± 81.5 mg/dL) with genetically confirmed homozygosity or compound heterozygosity for LDLR, APOB, PCSK9, or LDLRAP1 mutations received 12 biweekly infusions with CER-001 (8 mg/kg). Before and 1 hour after the first infusion, lipid values were measured. Magnetic resonance imaging (3-T magnetic resonance imaging) scans of the carotid arteries were acquired at baseline and after 24 weeks to assess changes in artery wall dimensions. After CER-001 infusion, apoA-I increased from 114.8 ± 20.7 mg/dL to 129.3 ± 23.0 mg/dL. After 24 weeks, mean vessel wall area (primary end point) decreased from 17.23 to 16.75 mm(2) (P = .008). A trend toward reduction of mean vessel wall thickness was observed (0.75 mm at baseline and 0.74 mm at follow-up, P = .0835). In HoFH, 12 biweekly infusions with an apoA-I-containing high-density lipoprotein-mimetic particle resulted in a significant reduction in carotid mean vessel wall area, implying that CER-001 may reverse atherogenic changes in the arterial wall on top of maximal low-density lipoprotein-lowering therapy. This finding supports further clinical evaluation of apoA-I-containing particles in patients with HoFH. Copyright © 2015 Mosby, Inc. All rights reserved.

Pirfenidone enhances the efficacy of combined radiation and sunitinib therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Seo-Hyun; Nam, Jae-Kyung; Jang, Junho

Radiotherapy is a widely used treatment for many tumors. Combination therapy using anti-angiogenic agents and radiation has shown promise; however, these combined therapies are reported to have many limitations in clinical trials. Here, we show that radiation transformed tumor endothelial cells (ECs) to fibroblasts, resulting in reduced vascular endothelial growth factor (VEGF) response and increased Snail1, Twist1, Type I collagen, and transforming growth factor (TGF)-β release. Irradiation of radioresistant Lewis lung carcinoma (LLC) tumors greater than 250 mm{sup 3} increased collagen levels, particularly in large tumor vessels. Furthermore, concomitant sunitinib therapy did not show a significant difference in tumor inhibition versusmore » radiation alone. Thus, we evaluated multimodal therapy that combined pirfenidone, an inhibitor of TGF-induced collagen production, with radiation and sunitinib treatment. This trimodal therapy significantly reduced tumor growth, as compared to radiation alone. Immunohistochemical analysis revealed that radiation-induced collagen deposition and tumor microvessel density were significantly reduced with trimodal therapy, as compared to radiation alone. These data suggest that combined therapy using pirfenidone may modulate the radiation-altered tumor microenvironment, thereby enhancing the efficacy of radiation therapy and concurrent chemotherapy. - Highlights: • Radiation changes tumor endothelial cells to fibroblasts. • Radio-resistant tumors contain collagen deposits, especially in tumor vessels. • Pirfenidone enhances the efficacy of combined radiation and sunitinib therapy. • Pirfenidone reduces radiation-induced collagen deposits in tumors.« less

Characteristics of wake-up stroke.

PubMed

Tanimoto, Aki; Mehndiratta, Prachi; Koo, Brian B

2014-07-01

Wake-up stroke (WUS) accounts for up to 29.6% of ischemic strokes, but its mechanisms are poorly understood. The purpose of this study is to identify risk factors and characteristics of WUS. Seven-two ischemic strokes were classified as WUS or non-WUS. Collected were demographic information, medical history, cholesterol profile, and stroke characteristics including severity (National Institutes of Health Stroke Scale [NIHSS]) and mechanism (Trial of Org 10172 in Acute Stroke Treatment criteria). Subjects completed questionnaires screening for sleep apnea (Berlin questionnaire) and assessing sleep characteristics. There were 72 ischemic strokes, of which 28 WUS (38.9%). WUS and non-WUS patients were similar in regard to stroke risk factors. WUS patients tended to be African American and were significantly younger. WUS was significantly more likely to result from small-vessel disease mechanism (42.9% versus 14.0%; P=.006) and tended to be less severe WUS (NIHSS score 3 [1, 4] versus 4 [2, 11]; P=.13) than non-WUS. Groups did not differ in regard to scoring positively on the Berlin questionnaire, but WUS sufferers were more likely to snore frequently (90.5% versus 70.0%, P=.08). The lipid profile was significantly worse in WUS compared with non-WUS (low-density lipoprotein 124.6±38.4 versus 103.7±36.8; P=.03; cholesterol to high-density lipoprotein ratio 5.2±1.6 versus 4.3±1.6; P=.02). WUS is more likely to result from small-vessel disease mechanism. Poorer cholesterol profile and frequent snoring may contribute to WUS. Published by Elsevier Inc.

Neuromuscular electrical stimulation improves GLUT-4 and morphological characteristics of skeletal muscle in rats with heart failure.

PubMed

de Leon, E B; Bortoluzzi, A; Rucatti, A; Nunes, R B; Saur, L; Rodrigues, M; Oliveira, U; Alves-Wagner, A B; Xavier, L L; Machado, U F; Schaan, B D; Dall'Ago, P

2011-02-01

Changes in skeletal muscle morphology and metabolism are associated with limited functional capacity in heart failure, which can be attenuated by neuromuscular electrical stimulation (ES). The purpose of the present study was to analyse the effects of ES upon GLUT-4 protein content, fibre structure and vessel density of the skeletal muscle in a rat model of HF subsequent to myocardial infarction. Forty-four male Wistar rats were assigned to one of four groups: sham (S), sham submitted to ES (S+ES), heart failure (HF) and heart failure submitted to ES (HF+ES). The rats in the ES groups were submitted to ES of the left leg during 20 days (2.5 kHz, once a day, 30 min, duty cycle 50%- 15 s contraction/15 s rest). After this period, the left tibialis anterior muscle was collected from all the rats for analysis. HF+ES rats showed lower values of lung congestion when compared with HF rats (P = 0.0001). Although muscle weight was lower in HF rats than in the S group, thus indicating hypotrophy, 20 days of ES led to their recovery (P < 0.0001). In both groups submitted to ES, there was an increase in muscle vessel density (P < 0.04). Additionally, heart failure determined a 49% reduction in GLUT-4 protein content (P < 0.03), which was recovered by ES (P < 0.01). In heart failure, ES improves morphological changes and raises GLUT-4 content in skeletal muscle. © 2010 The Authors. Acta Physiologica © 2010 Scandinavian Physiological Society.

Modeling of the contrast-enhanced perfusion test in liver based on the multi-compartment flow in porous media.

PubMed

Rohan, Eduard; Lukeš, Vladimír; Jonášová, Alena

2018-01-24

The paper deals with modeling the liver perfusion intended to improve quantitative analysis of the tissue scans provided by the contrast-enhanced computed tomography (CT). For this purpose, we developed a model of dynamic transport of the contrast fluid through the hierarchies of the perfusion trees. Conceptually, computed time-space distributions of the so-called tissue density can be compared with the measured data obtained from CT; such a modeling feedback can be used for model parameter identification. The blood flow is characterized at several scales for which different models are used. Flows in upper hierarchies represented by larger branching vessels are described using simple 1D models based on the Bernoulli equation extended by correction terms to respect the local pressure losses. To describe flows in smaller vessels and in the tissue parenchyma, we propose a 3D continuum model of porous medium defined in terms of hierarchically matched compartments characterized by hydraulic permeabilities. The 1D models corresponding to the portal and hepatic veins are coupled with the 3D model through point sources, or sinks. The contrast fluid saturation is governed by transport equations adapted for the 1D and 3D flow models. The complex perfusion model has been implemented using the finite element and finite volume methods. We report numerical examples computed for anatomically relevant geometries of the liver organ and of the principal vascular trees. The simulated tissue density corresponding to the CT examination output reflects a pathology modeled as a localized permeability deficiency.

Angiogenesis and lymphangiogenesis as prognostic factors after therapy in patients with cervical cancer

PubMed Central

Makarewicz, Roman; Kopczyńska, Ewa; Marszałek, Andrzej; Goralewska, Alina; Kardymowicz, Hanna

2012-01-01

Aim of the study This retrospective study attempts to evaluate the influence of serum vascular endothelial growth factor C (VEGF-C), microvessel density (MVD) and lymphatic vessel density (LMVD) on the result of tumour treatment in women with cervical cancer. Material and methods The research was carried out in a group of 58 patients scheduled for brachytherapy for cervical cancer. All women were patients of the Department and University Hospital of Oncology and Brachytherapy, Collegium Medicum in Bydgoszcz of Nicolaus Copernicus University in Toruń. VEGF-C was determined by means of a quantitative sandwich enzyme immunoassay using a human antibody VEGF-C ELISA produced by Bender MedSystem, enzyme-linked immunosorbent detecting the activity of human VEGF-C in body fluids. The measure for the intensity of angiogenesis and lymphangiogenesis in immunohistochemical reactions is the number of blood vessels within the tumour. Statistical analysis was done using Statistica 6.0 software (StatSoft, Inc. 2001). The Cox proportional hazards model was used for univariate and multivariate analyses. Univariate analysis of overall survival was performed as outlined by Kaplan and Meier. In all statistical analyses p < 0.05 (marked red) was taken as significant. Results In 51 patients who showed up for follow-up examination, the influence of the factors of angiogenesis, lymphangiogenesis, patients’ age and the level of haemoglobin at the end of treatment were assessed. Selected variables, such as patients’ age, lymph vessel density (LMVD), microvessel density (MVD) and the level of haemoglobin (Hb) before treatment were analysed by means of Cox logical regression as potential prognostic factors for lymph node invasion. The observed differences were statistically significant for haemoglobin level before treatment and the platelet number after treatment. The study revealed the following prognostic factors: lymph node status, FIGO stage, and kind of treatment. No statistically significant influence of angiogenic and lymphangiogenic factors on the prognosis was found. Conclusion Angiogenic and lymphangiogenic factors have no value in predicting response to radiotherapy in cervical cancer patients. PMID:23788848

Passive safety injection system using borated water

DOEpatents

Conway, Lawrence E.; Schulz, Terry L.

1993-01-01

A passive safety injection system relies on differences in water density to induce natural circulatory flow patterns which help maintain prescribed concentrations of boric acid in borated water, and prevents boron from accumulating in the reactor vessel and possibly preventing heat transfer.

Xylem vulnerability to cavitation can be accurately characterised in species with long vessels using a centrifuge method.

PubMed

Tobin, M F; Pratt, R B; Jacobsen, A L; De Guzman, M E

2013-05-01

Vulnerability to cavitation curves describe the decrease in xylem hydraulic conductivity as xylem pressure declines. Several techniques for constructing vulnerability curves use centrifugal force to induce negative xylem pressure in stem or root segments. Centrifuge vulnerability curves constructed for long-vesselled species have been hypothesised to overestimate xylem vulnerability to cavitation due to increased vulnerability of vessels cut open at stem ends that extend to the middle or entirely through segments. We tested two key predictions of this hypothesis: (i) centrifugation induces greater embolism than dehydration in long-vesselled species, and (ii) the proportion of open vessels changes centrifuge vulnerability curves. Centrifuge and dehydration vulnerability curves were compared for a long- and short-vesselled species. The effect of open vessels was tested in four species by comparing centrifuge vulnerability curves for stems of two lengths. Centrifuge and dehydration vulnerability curves agreed well for the long- and short-vesselled species. Centrifuge vulnerability curves constructed using two stem lengths were similar. Also, the distribution of embolism along the length of centrifuged stems matched the theoretical pressure profile induced by centrifugation. We conclude that vulnerability to cavitation can be accurately characterised with vulnerability curves constructed using a centrifuge technique, even in long-vesselled species. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

A novel mechanism of angiotensin II-regulated placental vascular tone in the development of hypertension in preeclampsia.

PubMed

Gao, Qinqin; Tang, Jiaqi; Li, Na; Zhou, Xiuwen; Li, Yongmei; Liu, Yanping; Wu, Jue; Yang, Yuxian; Shi, Ruixiu; He, Axin; Li, Xiang; Zhang, Yingying; Chen, Jie; Zhang, Lubo; Sun, Miao; Xu, Zhice

2017-05-09

The present study tested the hypothesis that angiotensin II plays a role in the regulation of placental vascular tone, which contributes to hypertension in preeclampsia. Functional and molecular assays were performed in large and micro placental and non-placental vessels from humans and animals. In human placental vessels, angiotensin II induced vasoconstrictions in 78.7% vessels in 155 tests, as referenced to KCl-induced contractions. In contrast, phenylephrine only produced contractions in 3.0% of 133 tests. In non-placental vessels, phenylephrine induced contractions in 76.0% of 67 tests, whereas angiotensin II failed to produce contractions in 75 tests. Similar results were obtained in animal placental and non-placental vessels. Compared with non-placental vessels, angiotensin II receptors and β-adrenoceptors were significantly increased in placental vessels. Compared to the vessels from normal pregnancy, angiotensin II-induced vasoconstrictions were significantly reduced in preeclamptic placentas, which was associated with a decrease in angiotensin II receptors. In addition, angiotensin II and angiotensin converting enzyme in the maternal-placenta circulation in preeclampsia were increased, whereas angiotensin I and angiotensin1-7 concentrations were unchanged. The study demonstrates a selective effect of angiotensin II in maintaining placental vessel tension, which may play an important role in development of hypertension in preeclampsia.

Refined pipe theory for mechanistic modeling of wood development.

PubMed

Deckmyn, Gaby; Evans, Sam P; Randle, Tim J

2006-06-01

We present a mechanistic model of wood tissue development in response to changes in competition, management and climate. The model is based on a refinement of the pipe theory, where the constant ratio between sapwood and leaf area (pipe theory) is replaced by a ratio between pipe conductivity and leaf area. Simulated pipe conductivity changes with age, stand density and climate in response to changes in allocation or pipe radius, or both. The central equation of the model, which calculates the ratio of carbon (C) allocated to leaves and pipes, can be parameterized to describe the contrasting stem conductivity behavior of different tree species: from constant stem conductivity (functional homeostasis hypothesis) to height-related reduction in stem conductivity with age (hydraulic limitation hypothesis). The model simulates the daily growth of pipes (vessels or tracheids), fibers and parenchyma as well as vessel size and simulates the wood density profile and the earlywood to latewood ratio from these data. Initial runs indicate the model yields realistic seasonal changes in pipe radius (decreasing pipe radius from spring to autumn) and wood density, as well as realistic differences associated with the competitive status of trees (denser wood in suppressed trees).

Very high cell density perfusion of CHO cells anchored in a non-woven matrix-based bioreactor.

PubMed

Zhang, Ye; Stobbe, Per; Silvander, Christian Orrego; Chotteau, Véronique

2015-11-10

Recombinant Chinese Hamster Ovary (CHO) cells producing IgG monoclonal antibody were cultivated in a novel perfusion culture system CellTank, integrating the bioreactor and the cell retention function. In this system, the cells were harbored in a non-woven polyester matrix perfused by the culture medium and immersed in a reservoir. Although adapted to suspension, the CHO cells stayed entrapped in the matrix. The cell-free medium was efficiently circulated from the reservoir into- and through the matrix by a centrifugal pump placed at the bottom of the bioreactor resulting in highly homogenous concentrations of the nutrients and metabolites in the whole system as confirmed by measurements from different sampling locations. A real-time biomass sensor using the dielectric properties of living cells was used to measure the cell density. The performances of the CellTank were studied in three perfusion runs. A very high cell density measured as 200 pF/cm (where 1 pF/cm is equivalent to 1 × 10(6)viable cells/mL) was achieved at a perfusion rate of 10 reactor volumes per day (RV/day) in the first run. In the second run, the effect of cell growth arrest by hypothermia at temperatures lowered gradually from 37 °C to 29 °C was studied during 13 days at cell densities above 100 pF/cm. Finally a production run was performed at high cell densities, where a temperature shift to 31 °C was applied at cell density 100 pF/cm during a production period of 14 days in minimized feeding conditions. The IgG concentrations were comparable in the matrix and in the harvest line in all the runs, indicating no retention of the product of interest. The cell specific productivity was comparable or higher than in Erlenmeyer flask batch culture. During the production run, the final harvested IgG production was 35 times higher in the CellTank compared to a repeated batch culture in the same vessel volume during the same time period. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

High density cell culture system

NASA Technical Reports Server (NTRS)

Spaulding, Glenn F. (Inventor)

1994-01-01

An annular culture vessel for growing mammalian cells is constructed in a one piece integral and annular configuration with an open end which is closed by an endcap. The culture vessel is rotatable about a horizontal axis by use of conventional roller systems commonly used in culture laboratories. The end wall of the endcap has tapered access ports to frictionally and sealingly receive the ends of hypodermic syringes. The syringes permit the introduction of fresh nutrient and withdrawal of spent nutrients. The walls are made of conventional polymeric cell culture material and are subjected to neutron bombardment to form minute gas permeable perforations in the walls.

Use of cornmeal bolus as an aid in obtaining cranial four-vessel angiograms.

PubMed

Weathers, R M; Lee, A

1975-01-01

In cranial angiography it has always been difficult to visualize extracranial vessels of the cervico-thoracic region, upon one radiograph, by using the same exposure factors for both regions. For this reason, we experimented and found that by applying a dry cornmeal bolus on specific areas of the neck a technically superior radiograph of these regions can be achieved. This bolus simulated added soft tissue to the cervical region. The density of the cervical region is now similar to that of the upper thoracic. As a result, factors set for one exposure will adequately penetrate both areas.

A mathematical model for the stressed state analysis of cylindrical laminated-composite pressure vessels

NASA Astrophysics Data System (ADS)

Bak, Roman; Matyja, Tomasz

An algorithm and a computer program have been developed for calculating the strength of pressure vessels made of laminated composites. Numerical results for pressure vessels of Kevlar 49 laminates are compared with experimental data in the literature.

Control of bed height in a fluidized bed gasification system

DOEpatents

Mehta, Gautam I.; Rogers, Lynn M.

1983-12-20

In a fluidized bed apparatus a method for controlling the height of the fdized bed, taking into account variations in the density of the bed. The method comprises taking simultaneous differential pressure measurements at different vertical elevations within the vessel, averaging the differential pressures, determining an average fluidized bed density, then periodically calculating a weighting factor. The weighting factor is used in the determination of the actual bed height which is used in controlling the fluidizing means.

Micro-CT measurements of tumoral vessels supplied by portal circulation in hepatic colorectal metastasis mouse model.

PubMed

Jun, Hong Young; Lee, Young Hwan; Juhng, Seon Kwan; Lee, Myeung Su; Oh, Jaemin; Yoon, Kwon-Ha

2014-06-01

The purpose of this study was to elucidate the micro CT findings of tumoral vessels supplied by portal circulation during establishment of hepatic metastasis of colorectal cancer in a mouse model. Hepatic metastases were induced in 15 BALB/c mice through the injection of murine colonic adenocarcinoma tumor cells into the mesenteric vein. Micro-CT imaging of the tumoral vessels was obtained to clarify the microvascular architecture. We evaluated the sinusoidal structure, diameter of the tumoral vessels (DTV) and blood vessel density (BVD) according to tumor sizes ranging from 201 to 3,000 µm in diameter. A total of 116 tumors were observed on day 15 after cell injection. The mean diameter of a normal hepatic sinusoid was 11.7 ± 2.0 µm on micro CT. The DTV supplied by the portal vein of tumors measuring 1,001-1,500 µm in diameter was greater than that of tumors 200-1,000 µm in diameter. The mean BVD from the portal vein gradually decrease according to size of tumor from 201 to 3,000 µm in diameter (r(2)  = -0.584, P < 0.01). The characteristics of tumoral vessels supplied by portal circulation during establishment of hepatic colorectal metastases were well visualized with micro-CT imaging. © 2014 Wiley Periodicals, Inc.

Prediction of Composite Pressure Vessel Failure Location using Fiber Bragg Grating Sensors

NASA Technical Reports Server (NTRS)

Kreger, Steven T.; Taylor, F. Tad; Ortyl, Nicholas E.; Grant, Joseph

2006-01-01

Ten composite pressure vessels were instrumented with fiber Bragg grating sensors in order to assess the strain levels of the vessel under various loading conditions. This paper and presentation will discuss the testing methodology, the test results, compare the testing results to the analytical model, and present a possible methodology for predicting the failure location and strain level of composite pressure vessels.

Effects of the duration of hyperlipidemia on cerebral lipids, vessels and neurons in rats.

PubMed

Yang, Weichun; Shi, He; Zhang, Jianfen; Shen, Ziyi; Zhou, Guangyu; Hu, Minyu

2017-01-31

The present study was designed to investigate the effects of hyperlipidemia on the cerebral lipids, vessels and neurons of rats, and to provide experimental evidence for subsequent intervention. One hundred adult SD rats, half of which were male and half of which were female, were randomly divided into five groups on the basis of serum total cholesterol (TC) levels. Four groups were fed a hypercholesterolemic diet (rat chow supplemented with 4% cholesterol, 1% cholic acid and 0.5% thiouracil - this is also called a CCT diet) for periods of 1 week, 2 weeks, 3 weeks and 4 weeks, respectively. A control group was included. The levels of serum lipids, cerebral lipids, free fatty acids (FFA), interleukin-6 (IL-6), interleukin-1 (IL-1), tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), oxidized low density lipoprotein (ox-LDL), A-beta precursor proteins (APP), amyloid beta (Aβ), glial fibrillary acidic protein (GFAP) and tight junction protein Claudin-5 were measured after the experiment. The pathologic changes and apoptosis of the rat brains were evaluated. Compared with the control group, after 1 week of a CCT diet, the levels of serum total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and brain triglycerides had increased by 2.40, 1.29 and 1.75 and 0.3 times, respectively. The serum high density lipoprotein cholesterol (HDL-C) had decreased by 0.74 times (P < 0.05) and the expression of IL-1, TNF-α and GFAP in the brains had increased (P < 0.05). In the second week, the expression of FFA and APP in the brains, and the amount of apoptotic neurons, had increased (P < 0.05). In the third week, the levels of VEGF, Ox-LDL and Aβ had increased, and the expression of Claudin-5 had decreased in the brains (P < 0.05). In the fourth week, the levels of TC, LDL-C and the amount of apoptotic neurons had increased (P < 0.05). The correlation analysis showed a positive correlation among FFA, TNF-α, VEGF, ox-LDL, Aβ, GFAP and neuronal apoptosis in the rat brains, and they all were negatively correlated with Claudin-5 (P < 0.05). Hyperlipidemia may activate astrocytes by means of high levels of TG that will have direct toxic effects on the cerebral vessels and neurons by causing the secretion of TNF-α and IL-1 in the brains of rats. In the metabolic procession, brain tissue was shown to generate FFA that aggravated the biosynthesis of ox-LDL. With the extension of the duration of hyperlipidemia, high levels of cerebral TC and LDL-C were shown to aggravate the deposition of Aβ, induce the secretion of VEGF, reduce the expression of tight junction protein Claudin-5 and change the permeability of blood-brain barriers to factors that could damage cerebral vessels and neurons.

Visualization of micro-capillaries using optical coherence tomography angiography with and without adaptive optics.

PubMed

Salas, Matthias; Augustin, Marco; Ginner, Laurin; Kumar, Abhishek; Baumann, Bernhard; Leitgeb, Rainer; Drexler, Wolfgang; Prager, Sonja; Hafner, Julia; Schmidt-Erfurth, Ursula; Pircher, Michael

2017-01-01

The purpose of this work is to investigate the benefits of adaptive optics (AO) technology for optical coherence tomography angiography (OCTA). OCTA has shown great potential in non-invasively enhancing the contrast of vessels and small capillaries. Especially the capability of the technique to visualize capillaries with a lateral extension that is below the transverse resolution of the system opens unique opportunities in diagnosing retinal vascular diseases. However, there are some limitations of this technology such as shadowing and projection artifacts caused by overlying vasculature or the inability to determine the true extension of a vessel. Thus, the evaluation of the vascular structure and density based on OCTA alone can be misleading. In this paper we compare the performance of AO-OCT, AO-OCTA and OCTA for imaging retinal vasculature. The improved transverse resolution and the reduced depth of focus of AO-OCT and AO-OCTA greatly reduce shadowing artifacts allowing for a better differentiation and segmentation of different vasculature layers of the inner retina. The comparison is done on images recorded in healthy volunteers and in diabetic patients with distinct pathologies of the retinal microvasculature.

Acoustic emission testing of composite vessels under sustained loading

NASA Technical Reports Server (NTRS)

Lark, R. F.; Moorhead, P. E.

1978-01-01

Acoustic emission (AE) tests have been conducted on small-diameter Kevlar 49/epoxy pressure vessels subjected to long-term sustained load-to-failure tests. Single-cycle burst tests were used as a basis for determining the test pressure in the sustained-loading tests. AE data from two vessel locations were compared. The data suggest that AE from vessel wall-mounted transducers is quite different for identical vessels subjected to the same pressure loading. AE from boss-mounted transducers yielded relatively consistent values. These values were not a function of time for vessel failure. The development of an AE test procedure for predicting the residual service life or integrity of composite vessels is discussed.

Endothelin-1–Rho kinase interactions impair lung structure and cause pulmonary hypertension after bleomycin exposure in neonatal rat pups

PubMed Central

Tseng, Nancy; Seedorf, Gregory; Kuhn, Katherine; Abman, Steven H.

2016-01-01

Bronchopulmonary dysplasia (BPD) is the chronic lung disease associated with premature birth, characterized by impaired vascular and alveolar growth. In neonatal rats bleomycin decreases lung growth and causes pulmonary hypertension (PH), which is poorly responsive to nitric oxide. In the developing lung, through Rho kinase (ROCK) activation, ET-1 impairs endothelial cell function; however, whether ET-1–ROCK interactions contribute to impaired vascular and alveolar growth in experimental BPD is unknown. Neonatal rats were treated daily with intraperitoneal bleomycin with and without selective ETA (BQ123/BQ610) and ETB (BQ788) receptor blockers, nonselective ET receptor blocker (ETRB) (bosentan), or fasudil (ROCK inhibitor). At day 14, lungs were harvested for morphometrics, and measurements of Fulton's index (RV/LV+S), medial wall thickness (MWT), and vessel density. Lung ET-1 protein and ROCK activity (phospho-MYPT-1:total MYPT-1 ratio) were also measured by Western blot analysis. Bleomycin increased lung ET-1 protein expression by 65%, RV/LV+S by 60%, mean linear intercept (MLI) by 212%, and MWT by 140% and decreased radial alveolar count (RAC) and vessel density by 40 and 44%, respectively (P < 0.01 for each comparison). After bleomycin treatment, fasudil and bosentan partially restored RAC and vessel density and decreased MLI, RV/LV+S, and MWT to normal values. Bleomycin increased ROCK activity by 120%, which was restored to normal values by bosentan but not selective ETRB. We conclude that ET-1–ROCK interactions contribute to decreased alveolar and vascular growth and PH in experimental BPD. We speculate that nonselective ETRB and ROCK inhibitors may be effective in the treatment of infants with BPD and PH. PMID:27760762

Endothelin-1-Rho kinase interactions impair lung structure and cause pulmonary hypertension after bleomycin exposure in neonatal rat pups.

PubMed

Gien, Jason; Tseng, Nancy; Seedorf, Gregory; Kuhn, Katherine; Abman, Steven H

2016-12-01

Bronchopulmonary dysplasia (BPD) is the chronic lung disease associated with premature birth, characterized by impaired vascular and alveolar growth. In neonatal rats bleomycin decreases lung growth and causes pulmonary hypertension (PH), which is poorly responsive to nitric oxide. In the developing lung, through Rho kinase (ROCK) activation, ET-1 impairs endothelial cell function; however, whether ET-1-ROCK interactions contribute to impaired vascular and alveolar growth in experimental BPD is unknown. Neonatal rats were treated daily with intraperitoneal bleomycin with and without selective ET A (BQ123/BQ610) and ET B (BQ788) receptor blockers, nonselective ET receptor blocker (ETRB) (bosentan), or fasudil (ROCK inhibitor). At day 14, lungs were harvested for morphometrics, and measurements of Fulton's index (RV/LV+S), medial wall thickness (MWT), and vessel density. Lung ET-1 protein and ROCK activity (phospho-MYPT-1:total MYPT-1 ratio) were also measured by Western blot analysis. Bleomycin increased lung ET-1 protein expression by 65%, RV/LV+S by 60%, mean linear intercept (MLI) by 212%, and MWT by 140% and decreased radial alveolar count (RAC) and vessel density by 40 and 44%, respectively (P < 0.01 for each comparison). After bleomycin treatment, fasudil and bosentan partially restored RAC and vessel density and decreased MLI, RV/LV+S, and MWT to normal values. Bleomycin increased ROCK activity by 120%, which was restored to normal values by bosentan but not selective ETRB. We conclude that ET-1-ROCK interactions contribute to decreased alveolar and vascular growth and PH in experimental BPD. We speculate that nonselective ETRB and ROCK inhibitors may be effective in the treatment of infants with BPD and PH. Copyright © 2016 the American Physiological Society.

The efficacy of acrylic acid grafting and arginine-glycine-aspartic acid peptide immobilization on fibrovascular ingrowth into porous polyethylene implants in rabbits.

PubMed

Park, Byung Woo; Yang, Hee Seok; Baek, Se Hyun; Park, Kwideok; Han, Dong Keun; Lee, Tae Soo

2007-06-01

To determine the effects of acrylic acid (AA) grafting by argon plasma treatment and of immobilization of arginine-glycine-aspartic acid (RGD) peptides on fibrovascular ingrowth rate into high-density porous polyethylene (HPPE) anophthalmic orbital implants. Sixty rabbits were divided into three groups, with 20 rabbits in each group: (1) control group, rabbits implanted with unmodified HPPE; (2) PAA group, rabbits implanted with HPPE grafted with poly(AA) by argon plasma treatment; (3) RGD group, rabbits implanted with HPPE grafted with AA by argon plasma treatment and subsequently immobilized with RGD peptide. An HPPE spherical implant was put in the abdominal muscles of rabbit. After implantation for 4 weeks, the retrieved implants were sectioned and stained with hematoxylin and eosin (H&E). Blood vessels were counted using CD-31 immunostaining. Cross-sectional areas of fibrovascular ingrowth, blood vessel densities, and host inflammatory response scores were determined for all three groups. The mean cross-sectional areas of fibrovascularization at 2 and 3 weeks after implantation were the greatest in the RGD group, followed by the PAA group. While minimal fibrovascular ingrowths were noted in all implants at 1 week, all the implants showed nearly complete ingrowth at 4 weeks. Blood vessel densities were the highest in the RGD group, followed by the PAA group at 2, 3, and 4 weeks. The mean inflammation scores of the PAA and RGD groups were less than that of the control group. Fibrovascularization into HPPE implants was enhanced by surface grafting of AA and further improved by immobilizing RGD peptides onto the grafted AA surfaces. The inflammatory reactions were mild by either technique of surface modification.

Adult responses to an ischemic stroke in a rat model of neonatal stress and morphine treatment.

PubMed

Hays, Sarah L; Valieva, Olga A; McPherson, Ronald J; Juul, Sandra E; Gleason, Christine A

2013-02-01

Critically ill newborn infants experience stressors that may alter brain development. Using a rodent model, we previously showed that neonatal stress, morphine, and stress plus morphine treatments each influence early gene expression and may impair neurodevelopment and learning behavior. We hypothesized that the combination of neonatal stress with morphine may alter neonatal angiogenesis and/or adult cerebral blood vessel density and thus increase injury after cerebral ischemia in adulthood. To test this, neonatal Lewis rats underwent 8 h/d maternal separation, plus morning/afternoon hypoxia exposure and either saline or morphine treatment (2 mg/kg s.c.) from postnatal day 3-7. A subset received bromodeoxyuridine to track angiogenesis. Adult brains were stained with collagen IV to quantify cerebral blood vessel density. To examine vulnerability to brain injury, postnatal day 80 adult rats underwent right middle cerebral artery occlusion (MCAO) to produce unilateral ischemic lesions. Brains were removed and processed for histology 48 h after injury. Brain injury was assessed by histological evaluation of hematoxylin and eosin, and silver staining. In contrast to our hypothesis, neither neonatal morphine, stress, nor the combination affected cerebral vessel density or MCAO-induced brain injury. Neonatal angiogenesis was not detected in adult rats possibly due to turnover of endothelial cells. Although unrelated to angiogenesis, hippocampal granule cell neurogenesis was detected and there was a trend (P = 0.073) toward increased bromodeoxyuridine incorporation in rats that underwent neonatal stress. These findings are discussed in contrast to other data concerning the effects of morphine on cerebrovascular function, and acute effects of morphine on hippocampal neurogenesis. Copyright © 2012 ISDN. Published by Elsevier Ltd. All rights reserved.

Simple and Inexpensive Paper-Based Astrocyte Co-culture to Improve Survival of Low-Density Neuronal Networks

PubMed Central

Aebersold, Mathias J.; Thompson-Steckel, Greta; Joutang, Adriane; Schneider, Moritz; Burchert, Conrad; Forró, Csaba; Weydert, Serge; Han, Hana; Vörös, János

2018-01-01

Bottom-up neuroscience aims to engineer well-defined networks of neurons to investigate the functions of the brain. By reducing the complexity of the brain to achievable target questions, such in vitro bioassays better control experimental variables and can serve as a versatile tool for fundamental and pharmacological research. Astrocytes are a cell type critical to neuronal function, and the addition of astrocytes to neuron cultures can improve the quality of in vitro assays. Here, we present cellulose as an astrocyte culture substrate. Astrocytes cultured on the cellulose fiber matrix thrived and formed a dense 3D network. We devised a novel co-culture platform by suspending the easy-to-handle astrocytic paper cultures above neuronal networks of low densities typically needed for bottom-up neuroscience. There was significant improvement in neuronal viability after 5 days in vitro at densities ranging from 50,000 cells/cm2 down to isolated cells at 1,000 cells/cm2. Cultures exhibited spontaneous spiking even at the very low densities, with a significantly greater spike frequency per cell compared to control mono-cultures. Applying the co-culture platform to an engineered network of neurons on a patterned substrate resulted in significantly improved viability and almost doubled the density of live cells. Lastly, the shape of the cellulose substrate can easily be customized to a wide range of culture vessels, making the platform versatile for different applications that will further enable research in bottom-up neuroscience and drug development. PMID:29535595

Intra-and inter-observer reliability of nailfold videocapillaroscopy - A possible outcome measure for systemic sclerosis-related microangiopathy.

PubMed

Dinsdale, Graham; Moore, Tonia; O'Leary, Neil; Tresadern, Philip; Berks, Michael; Roberts, Christopher; Manning, Joanne; Allen, John; Anderson, Marina; Cutolo, Maurizio; Hesselstrand, Roger; Howell, Kevin; Pizzorni, Carmen; Smith, Vanessa; Sulli, Alberto; Wildt, Marie; Taylor, Christopher; Murray, Andrea; Herrick, Ariane L

2017-07-01

Our aim was to assess the reliability of nailfold capillary assessment in terms of image evaluability, image severity grade ('normal', 'early', 'active', 'late'), capillary density, capillary (apex) width, and presence of giant capillaries, and also to gain further insight into differences in these parameters between patients with systemic sclerosis (SSc), patients with primary Raynaud's phenomenon (PRP) and healthy control subjects. Videocapillaroscopy images (magnification 300×) were acquired from all 10 digits from 173 participants: 101 patients with SSc, 22 with PRP and 50 healthy controls. Ten capillaroscopy experts from 7 European centres evaluated the images. Custom image mark-up software allowed extraction of the following outcome measures: overall grade ('normal', 'early', 'active', 'late', 'non-specific', or 'ungradeable'), capillary density (vessels/mm), mean vessel apical width, and presence of giant capillaries. Observers analysed a median of 129 images each. Evaluability (i.e. the availability of measures) varied across outcome measures (e.g. 73.0% for density and 46.2% for overall grade in patients with SSc). Intra-observer reliability for evaluability was consistently higher than inter- (e.g. for density, intra-class correlation coefficient [ICC] was 0.71 within and 0.14 between observers). Conditional on evaluability, both intra- and inter-observer reliability were high for grade (ICC 0.93 and 0.78 respectively), density (0.91 and 0.64) and width (0.91 and 0.85). Evaluability is one of the major challenges in assessing nailfold capillaries. However, when images are evaluable, the high intra- and inter-reliabilities suggest that overall image grade, capillary density and apex width have potential as outcome measures in longitudinal studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Improvement of retinal blood vessel detection using morphological component analysis.

PubMed

Imani, Elaheh; Javidi, Malihe; Pourreza, Hamid-Reza

2015-03-01

Detection and quantitative measurement of variations in the retinal blood vessels can help diagnose several diseases including diabetic retinopathy. Intrinsic characteristics of abnormal retinal images make blood vessel detection difficult. The major problem with traditional vessel segmentation algorithms is producing false positive vessels in the presence of diabetic retinopathy lesions. To overcome this problem, a novel scheme for extracting retinal blood vessels based on morphological component analysis (MCA) algorithm is presented in this paper. MCA was developed based on sparse representation of signals. This algorithm assumes that each signal is a linear combination of several morphologically distinct components. In the proposed method, the MCA algorithm with appropriate transforms is adopted to separate vessels and lesions from each other. Afterwards, the Morlet Wavelet Transform is applied to enhance the retinal vessels. The final vessel map is obtained by adaptive thresholding. The performance of the proposed method is measured on the publicly available DRIVE and STARE datasets and compared with several state-of-the-art methods. An accuracy of 0.9523 and 0.9590 has been respectively achieved on the DRIVE and STARE datasets, which are not only greater than most methods, but are also superior to the second human observer's performance. The results show that the proposed method can achieve improved detection in abnormal retinal images and decrease false positive vessels in pathological regions compared to other methods. Also, the robustness of the method in the presence of noise is shown via experimental result. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Root resistance to cavitation is accurately measured using a centrifuge technique.

PubMed

Pratt, R B; MacKinnon, E D; Venturas, M D; Crous, C J; Jacobsen, A L

2015-02-01

Plants transport water under negative pressure and this makes their xylem vulnerable to cavitation. Among plant organs, root xylem is often highly vulnerable to cavitation due to water stress. The use of centrifuge methods to study organs, such as roots, that have long vessels are hypothesized to produce erroneous estimates of cavitation resistance due to the presence of open vessels through measured samples. The assumption that roots have long vessels may be premature since data for root vessel length are sparse; moreover, recent studies have not supported the existence of a long-vessel artifact for stems when a standard centrifuge technique was used. We examined resistance to cavitation estimated using a standard centrifuge technique and compared these values with native embolism measurements for roots of seven woody species grown in a common garden. For one species we also measured vulnerability using single-vessel air injection. We found excellent agreement between root native embolism and the levels of embolism measured using a centrifuge technique, and with air-seeding estimates from single-vessel injection. Estimates of cavitation resistance measured from centrifuge curves were biologically meaningful and were correlated with field minimum water potentials, vessel diameter (VD), maximum xylem-specific conductivity (Ksmax) and vessel length. Roots did not have unusually long vessels compared with stems; moreover, root vessel length was not correlated to VD or to the vessel length of stems. These results suggest that root cavitation resistance can be accurately and efficiently measured using a standard centrifuge method and that roots are highly vulnerable to cavitation. The role of root cavitation resistance in determining drought tolerance of woody species deserves further study, particularly in the context of climate change. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

In vitro experiments of vessel wall apposition between the Enterprise and Enterprise 2 stents for treatment of cerebral aneurysms.

PubMed

Kono, Kenichi; Terada, Tomoaki

2016-02-01

A closed-cell stent called Enterprise has been used for stent-assisted coil embolization of cerebral aneurysms. The Enterprise stent tends to cause kinks and vessel wall malposition in curved vessels and may cause thromboembolic complications. We evaluated vessel wall apposition of a new closed-cell stent, Enterprise 2, compared with a previous Enterprise stent, using curved vascular silicone models. The Enterprise or Enterprise 2 stent was deployed in curved vascular models with various radii of approximately 5 to 10 mm. Stent deployment was performed 25 times in each stent. A push-pull technique was used to minimize incomplete wall apposition. To evaluate conformity of stents, gaps between a stent and a vessel wall were measured. The gap ratio (gap / a wall diameter) was 15 % ± 17 % (mean ± standard deviation) and 41 % ± 15 % with the Enterprise 2 stent and the Enterprise stent, respectively. Taking gap ratios and radii of vessel curvature into consideration, the Enterprise 2 stent had significantly better wall apposition than the Enterprise stent (p = 0.005). In the same radius of vessel curvature, the Enterprise 2 stent had approximately half of the gap compared with the Enterprise stent. There were no significant differences in vessel straightening effects between the two stents. The Enterprise 2 stent has better wall apposition in curved vessels than the Enterprise stent. The gap between a vessel wall and the Enterprise 2 stent is approximately half that of the Enterprise stent. However, gaps and kinks are still present in curved vessels with a small radius. Caution should be taken for kinks and malposition in acutely curved vessels, such as the siphon of the internal carotid artery.

Microcirculation and its relation to continuous subcutaneous glucose sensor accuracy in cardiac surgery patients in the intensive care unit.

PubMed

Siegelaar, Sarah E; Barwari, Temo; Hermanides, Jeroen; van der Voort, Peter H J; Hoekstra, Joost B L; DeVries, J Hans

2013-11-01

Continuous glucose monitoring could be helpful for glucose regulation in critically ill patients; however, its accuracy is uncertain and might be influenced by microcirculation. We investigated the microcirculation and its relation to the accuracy of 2 continuous glucose monitoring devices in patients after cardiac surgery. The present prospective, observational study included 60 patients admitted for cardiac surgery. Two continuous glucose monitoring devices (Guardian Real-Time and FreeStyle Navigator) were placed before surgery. The relative absolute deviation between continuous glucose monitoring and the arterial reference glucose was calculated to assess the accuracy. Microcirculation was measured using the microvascular flow index, perfused vessel density, and proportion of perfused vessels using sublingual sidestream dark-field imaging, and tissue oxygenation using near-infrared spectroscopy. The associations were assessed using a linear mixed-effects model for repeated measures. The median relative absolute deviation of the Navigator was 11% (interquartile range, 8%-16%) and of the Guardian was 14% (interquartile range, 11%-18%; P = .05). Tissue oxygenation significantly increased during the intensive care unit admission (maximum 91.2% [3.9] after 6 hours) and decreased thereafter, stabilizing after 20 hours. A decrease in perfused vessel density accompanied the increase in tissue oxygenation. Microcirculatory variables were not associated with sensor accuracy. A lower peripheral temperature (Navigator, b = -0.008, P = .003; Guardian, b = -0.006, P = .048), and for the Navigator, also a higher Acute Physiology and Chronic Health Evaluation IV predicted mortality (b = 0.017, P < .001) and age (b = 0.002, P = .037) were associated with decreased sensor accuracy. The results of the present study have shown acceptable accuracy for both sensors in patients after cardiac surgery. The microcirculation was impaired to a limited extent compared with that in patients with sepsis and healthy controls. This impairment was not related to sensor accuracy but the peripheral temperature for both sensors and patient age and Acute Physiology and Chronic Health Evaluation IV predicted mortality for the Navigator were. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Carbon fiber internal pressure vessels

NASA Technical Reports Server (NTRS)

Simon, R. A.

1973-01-01

Internal pressure vessels were designed; the filament was wound of carbon fibers and epoxy resin and tested to burst. The fibers used were Thornel 400, Thornel 75, and Hercules HTS. Additional vessels with type A fiber were made. Polymeric linears were used, and all burst testing was done at room temperature. The objective was to produce vessels with the highest attainable PbV/W efficiencies. The type A vessels showed the highest average efficiency: 2.56 x 10 to the 6th power cm. Next highest efficiency was with Thornel 400 vessels: 2.21 x 10 to the 6th power cm. These values compare favorably with efficiency values from good quality S-glass vessels, but strains averaged 0.97% or less, which is less than 1/3 the strain of S-glass vessels.

Intravascular perfusion of carbon black ink allows reliable visualization of cerebral vessels.

PubMed

Hasan, Mohammad R; Herz, Josephine; Hermann, Dirk M; Doeppner, Thorsten R

2013-01-04

The anatomical structure of cerebral vessels is a key determinant for brain hemodynamics as well as the severity of injury following ischemic insults. The cerebral vasculature dynamically responds to various pathophysiological states and it exhibits considerable differences between strains and under conditions of genetic manipulations. Essentially, a reliable technique for intracranial vessel staining is essential in order to study the pathogenesis of ischemic stroke. Until recently, a set of different techniques has been employed to visualize the cerebral vasculature including injection of low viscosity resin, araldite F, gelatin mixed with various dyes (i.e. carmine red, India ink) or latex with or without carbon black. Perfusion of white latex compound through the ascending aorta has been first reported by Coyle and Jokelainen. Maeda et al. have modified the protocol by adding carbon black ink to the latex compound for improved contrast visualization of the vessels after saline perfusion of the brain. However, inefficient perfusion and inadequate filling of the vessels are frequently experienced due to high viscosity of the latex compound. Therefore, we have described a simple and cost-effective technique using a mixture of two commercially available carbon black inks (CB1 and CB2) to visualize the cerebral vasculature in a reproducible manner. We have shown that perfusion with CB1+CB2 in mice results in staining of significantly smaller cerebral vessels at a higher density in comparison to latex perfusion. Here, we describe our protocol to identify the anastomotic points between the anterior (ACA) and middle cerebral arteries (MCA) to study vessel variations in mice with different genetic backgrounds. Finally, we demonstrate the feasibility of our technique in a transient focal cerebral ischemia model in mice by combining CB1+CB2-mediated vessel staining with TTC staining in various degrees of ischemic injuries.

Environmental Implications of Maritime Vessel Intensification in Arctic Waters

NASA Astrophysics Data System (ADS)

Stevenson, T. C.; Banis, D.; Sheard, W.

2016-12-01

In 2016, the Arctic experienced some of the warmest monthly temperatures on record. Record high temperatures in the Arctic continue to cause rapid sea ice declines, opening new areas of ocean to commercial exploitation and transportation and causing significant reductions in critical sea ice habitats used by iconic species. Elevated maritime vessel traffic in the Arctic is projected to increase black carbon emissions, encourage the spread of invasive species, increase mammal strikes, intensify conflict with smaller subsistence boats, and heighten oil spill risks. The Arctic Council, an intergovernmental organization concerned with sustainable development and environmental protection, is working with member countries, indigenous participants and other groups on developing networks of marine protected areas within ecologically or biologically important areas. To help inform that process, we analyzed vessel traffic and marine protected area coverage occurring within ecologically or biologically significant areas in the circumpolar Arctic. Our preliminary findings suggest vessel traffic within ecologically or biologically significant areas were highest around Iceland, Norway, Russia and United States but differed by vessel type. The density of fishing vessels occurring within ecologically or biologically important areas were highest near Norway, Iceland, Faroe Islands, parts of Greenland and United States, whereas vessels carrying liquefied natural gas and oil were concentrated near Norway and Russia. The percentage of area covered by marine protected areas within ecologically or biologically significant areas was low, with the exception of places like Wrangel Island, Svalbard, and areas around Greenland. These findings are important because it illustrates ecologically or biologically significant areas in the Arctic are vulnerable to projected vessel traffic intensification and the level of protection afforded by marine protected areas is relatively low.

Vascularization after treatment of gingival recession defects with platelet-rich fibrin or connective tissue graft.

PubMed

Eren, Gülnihal; Kantarcı, Alpdoğan; Sculean, Anton; Atilla, Gül

2016-11-01

The aim of this study was to evaluate histologically the following treatment of bilateral localized gingival recessions with coronally advanced flap (CAF) combined with platelet-rich fibrin (PRF) or subepithelial connective tissue graft (SCTG). Tissue samples were harvested from 14 subjects either 1 or 6 months after the surgeries. The 2-mm punch biopsies were obtained from the mid-portion of the grafted sites. Neutral buffered formalin fixed, paraffin-embedded 5-μm thick tissue sections were stained with hematoxylin eosin and Masson's trichrome in order to analyze the collagen framework, epithelium thickness and rete-peg length. Multiple sequential sections were cut from paraffin-embedded blocks of tissue and immunohistochemically prepared for detection of vascular endothelial growth factor, CD31 and CD34, for the assessment of vascularization. Rete peg formation was significantly increased in the sites treated with PRF compared to the SCTG group after 6 months (p < 0.05). On the contrary, the number of vessels was increased in the SCTG group compared to the PRF group after 6 months (p < 0.05). No statistically significant differences were observed in the collagen density. Staining intensity of CD31 increased in submucosal area of PRF group than SCTG group after 1 month. Higher staining intensity of CD34 was observed in the submucosal area of PRF group compared with SCTG group after 6 months. The results of the present study suggest that in histological evaluation because of its biological compounds, PRF results earlier vessel formation and tissue maturation compared to connective tissue graft. PRF regulated the vascular response associated with an earlier wound healing.

Microvessel density and angiogenesis in primary hepatic malignancies: Differential expression of CD31 and VEGFR-2 in hepatocellular carcinoma and intrahepatic cholangiocarcinoma.

PubMed

Bösmüller, Hans; Pfefferle, Vanessa; Bittar, Zeid; Scheble, Veit; Horger, Marius; Sipos, Bence; Fend, Falko

2018-06-19

Microvessel density is an indicator of tumor-driven neoangiogenesis. Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) have distinct vascular patterns, which are also reflected in their imaging characteristics. Since a significant proportion of HCC are treated without biopsy confirmation, it is essential to discriminate HCC and ICC radiologically. The aim of our study was therefore to compare microvessel density and expression of VEGFR-2 in HCC and ICC, since these data may ultimately help us to better understand their imaging characteristics. Whereas CD31 documents vessel density, VEGFR-2 expression is an indicator of tumor-related neoangiogenesis. CD31 and VEGFR-2 expressing microvessels were quantified on tissue microarrays of 95 resection specimens of HCC and 47 cases of ICC. Microvessel density was evaluated by counting immuno-reactive vascular structures both within the tumor and adjacent liver control tissue, respectively. Further 16 cases of ICC were immunostained for CD31 and VEGFR-2 on full sections. The frequency of VEGFR-2 (46.2/HPF; range 0-150) and CD31 (61.2/HPF; range 2.6-140) expressing vascular structures was significantly increased in HCC compared to adjacent liver parenchyma (VEGFR-2 33.3/HPF, range 0-87, CD31 21.4/HPF, range 0-78, both p < 0,001). ICC revealed significantly less VEGFR2-positive microvessels (15.4/HPF; range 2-77) compared to matched control tissue (42.3/HPF; range 4.6-109), whereas microvessel density with CD31 was comparable between ICC and adjacent liver (32.1/HPF; range 5.3-78 versus 28.0/HPF; range 5.3-57; p = 0.89). In ICC, the tumor-to-normal microvessel density ratio was 0.38 for VEGFR-2 and 1.24 for CD31. These ratios were nearly identical (VEGFR: 0.38; CD31: 0,97) for the 16 cases of ICC studied on whole sections, confirming the validity of the TMA approach. In contrast, ratios of VEGFR-2 and CD31 in HCC vs. adjacent liver were significantly higher (VEGFR: 2.23; CD31: 6.57). Expression of VEGFR-2 by tumor cells was not observed in any of the cases. HCC and ICC differ significantly in their microvessel density, confirming the hypovascular nature of ICC as compared to the hypervascularity of HCC. Of note, inverse tumor-to-normal ratios of microvascular VEGFR-2 expression between the two neoplasms indicate distinct features of neoangiogenesis. Whether these differences can be exploited for improvements in imaging of hepatic tumors and may play a role for anti-angiogenic treatment strategies requires further studies. Copyright © 2018 Elsevier GmbH. All rights reserved.

Notes on Experiments.

ERIC Educational Resources Information Center

Physics Education, 1984

1984-01-01

Describes (1) oil slick interference rings in the laboratory; (2) cracking of glass by impact; (3) multipurpose prism for refractometry and light path demonstrations; and (4) determination of liquid densities and volumes of solid bodies by the reaction force on a vessel. Procedures used and equipment needed are discussed. (JN)

Radiated Power and Impurity Concentrations in the EXTRAP-T2R Reversed-Field Pinch

NASA Astrophysics Data System (ADS)

Corre, Y.; Rachlew, E.; Cecconello, M.; Gravestijn, R. M.; Hedqvist, A.; Pégourié, B.; Schunke, B.; Stancalie, V.

2005-01-01

A numerical and experimental study of the impurity concentration and radiation in the EXTRAP-T2R device is reported. The experimental setup consists of an 8-chord bolometer system providing the plasma radiated power and a vacuum-ultraviolet spectrometer providing information on the plasma impurity content. The plasma emissivity profile as measured by the bolometric system is peaked in the plasma centre. A one dimensional Onion Skin Collisional-Radiative model (OSCR) has been developed to compute the density and radiation distributions of the main impurities. The observed centrally peaked emissivity profile can be reproduced by OSCR simulations only if finite particle confinement time and charge-exchange processes between plasma impurities and neutral hydrogen are taken into account. The neutral hydrogen density profile is computed with a recycling code. Simulations show that recycling on metal first wall such as in EXTRAP-T2R (stainless steel vacuum vessel and molybdenum limiters) is compatible with a rather high neutral hydrogen density in the plasma centre. Assuming an impurity concentration of 10% for oxygen and 3% for carbon compared with the electron density, the OSCR calculation including lines and continuum emission reproduces about 60% of the total radiated power with a similarly centrally peaked emissivity profile. The centrally peaked emissivity profile is due to low ionisation stages and strongly radiating species in the plasma core, mainly O4+ (Be-like) and C3+ Li-like.

Control of plasma stored energy for burn control using DIII-D in-vessel coils

DOE PAGES

Hawryluk, Richard J.; Eidietis, Nicholas W.; Grierson, Brian A.; ...

2015-04-09

A new approach has been experimentally demonstrated to control the stored energy by applying a non-axisymmetric magnetic field using the DIII-D in-vessel coils to modify the energy confinement time. In future burning plasma experiments as well as magnetic fusion energy power plants, various concepts have been proposed to control the fusion power. The fusion power in a power plant operating at high gain can be related to the plasma stored energy and hence, is a strong function of the energy confinement time. Thus, an actuator that modifies the confinement time can be used to adjust the fusion power. In relativelymore » low collisionality DIII-D discharges, the application of nonaxisymmetric magnetic fields results in a decrease in confinement time and density pumpout. Furthermore, gas puffing was used to compensate the density pumpout in the pedestal while control of the stored energy was demonstrated by the application of non-axisymmetric fields.« less

Prediction of occult lymph node metastasis in squamous cell carcinoma of the oral cavity and the oropharynx using peritumoral Prospero homeobox protein 1 lymphatic nuclear quantification.

PubMed

Mermod, Maxime; Bongiovanni, Massimo; Petrova, Tatiana V; Dubikovskaya, Elena A; Simon, Christian; Tolstonog, Genrich; Monnier, Yan

2016-09-01

The use of lymphatic vessel density as a predictor of occult lymph node metastasis (OLNM) in head and neck squamous cell carcinoma (HNSCC) has never been reported. Staining of the specific lymphatic endothelial cells nuclear marker, PROX1, as an indicator of lymphatic vessel density was determined by counting the number of positive cells in squamous cell carcinomas (SCCs) of the oral cavity and the oropharynx with clinically negative necks. Correlation with histopathological data was established. Peritumoral PROX1 lymphatic nuclear count significantly correlated with the detection of OLNM in multivariate analysis (p < .005). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of this parameter was 60%, 95%, 85%, and 90%, respectively. Peritumoral PROX1 lymphatic nuclear count in primary SCCs of the oral cavity and the oropharynx allows accurate prediction of occult lymph node metastasis. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1407-1415, 2016. © 2016 Wiley Periodicals, Inc.

Method for making a uranium chloride salt product

DOEpatents

Miller, William E [Naperville, IL; Tomczuk, Zygmunt [Lockport, IL

2004-10-05

The subject apparatus provides a means to produce UCl.sub.3 in large quantities without incurring corrosion of the containment vessel or associated apparatus. Gaseous Cl is injected into a lower layer of Cd where CdCl.sub.2 is formed. Due to is lower density, the CdCl.sub.2 rises through the Cd layer into a layer of molten LiCl--KCL salt where a rotatable basket containing uranium ingots is suspended. The CdCl.sub.2 reacts with the uranium to form UCl.sub.3 and Cd. Due to density differences, the Cd sinks down to the liquid Cd layer and is reused. The UCl.sub.3 combines with the molten salt. During production the temperature is maintained at about 600.degree. C. while after the uranium has been depleted the salt temperature is lowered, the molten salt is pressure siphoned from the vessel, and the salt product LiCl--KCl-30 mol % UCl.sub.3 is solidified.

LRP1 protects the vasculature by regulating levels of connective tissue growth factor and HtrA1.

PubMed

Muratoglu, Selen C; Belgrave, Shani; Hampton, Brian; Migliorini, Mary; Coksaygan, Turhan; Chen, Ling; Mikhailenko, Irina; Strickland, Dudley K

2013-09-01

Low-density lipoprotein receptor-related protein 1 (LRP1) is a large endocytic and signaling receptor that is abundant in vascular smooth muscle cells. Mice in which the lrp1 gene is deleted in smooth muscle cells (smLRP1(-/-)) on a low-density lipoprotein receptor-deficient background display excessive platelet derived growth factor-signaling, smooth muscle cell proliferation, aneurysm formation, and increased susceptibility to atherosclerosis. The objectives of the current study were to examine the potential of LRP1 to modulate vascular physiology under nonatherogenic conditions. We found smLRP1(-/-) mice to have extensive in vivo aortic dilatation accompanied by disorganized and degraded elastic lamina along with medial thickening of the arterial vessels resulting from excess matrix deposition. Surprisingly, this was not attributable to excessive platelet derived growth factor-signaling. Rather, quantitative differential proteomic analysis revealed that smLRP1(-/-) vessels contain a 4-fold increase in protein levels of high-temperature requirement factor A1 (HtrA1), which is a secreted serine protease that is known to degrade matrix components and to impair elastogenesis, resulting in fragmentation of elastic fibers. Importantly, our study discovered that HtrA1 is a novel LRP1 ligand. Proteomics analysis also identified excessive accumulation of connective tissue growth factor, an LRP1 ligand and a key mediator of fibrosis. Our findings suggest a critical role for LRP1 in maintaining the integrity of vessels by regulating protease activity as well as matrix deposition by modulating HtrA1 and connective tissue growth factor protein levels. This study highlights 2 new molecules, connective tissue growth factor and HtrA1, which contribute to detrimental changes in the vasculature and, therefore, represent new target molecules for potential therapeutic intervention to maintain vessel wall homeostasis.

Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

NASA Astrophysics Data System (ADS)

Ogami, M.; Kulkarni, R.; Wang, H.; Reif, R.; Wang, R. K.

2014-08-01

We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, Kurt; Krueger, Sarah A.; Kane, Jonathan L.

Purpose: To assess the efficacy of 3-week schedules of low-dose pulsed radiation treatment (PRT) and standard radiation therapy (SRT), with concurrent cisplatin (CDDP) in a head and neck squamous cell carcinoma xenograft model. Methods and Materials: Subcutaneous UT-SCC-14 tumors were established in athymic NIH III HO female mice. A total of 30 Gy was administered as 2 Gy/d, 5 d/wk for 3 weeks, either by PRT (10 × 0.2 Gy/d, with a 3-minute break between each 0.2-Gy dose) or SRT (2 Gy/d, uninterrupted delivery) in combination with concurrent 2 mg/kg CDDP 3 times per week in the final 2 weeks of radiation therapy. Treatment-induced growth delays were defined from twice-weeklymore » tumor volume measurements. Tumor hypoxia was assessed by {sup 18}F-fluoromisonidazole positron emission tomography imaging, and calculated maximum standardized uptake values compared with tumor histology. Tumor vessel density and hypoxia were measured by quantitative immunohistochemistry. Normal tissues effects were evaluated in gut and skin. Results: Untreated tumors grew to 1000 mm{sup 3} in 25.4 days (±1.2), compared with delays of 62.3 days (±3.5) for SRT + CDDP and 80.2 days (±5.0) for PRT + CDDP. Time to reach 2× pretreatment volume ranged from 8.2 days (±1.8) for untreated tumors to 67.1 days (±4.7) after PRT + CDDP. Significant differences in tumor growth delay were observed for SRT versus SRT + CDDP (P=.04), PRT versus PRT + CDDP (P=.035), and SRT + CDDP versus PRT + CDDP (P=.033), and for survival between PRT versus PRT + CDDP (P=.017) and SRT + CDDP versus PRT + CDDP (P=.008). Differences in tumor hypoxia were evident by {sup 18}F-fluoromisonidazole positron emission tomography imaging between SRT and PRT (P=.025), although not with concurrent CDDP. Tumor vessel density differed between SRT + CDDP and PRT + CDDP (P=.011). No differences in normal tissue parameters were seen. Conclusions: Concurrent CDDP was more effective in combination PRT than SRT at restricting tumor growth. Significant differences in tumor vascular density were evident between PRT and SRT, suggesting a preservation of vascular network with PRT.« less

Noninvasive imaging of human foveal capillary network using dual-conjugate adaptive optics.

PubMed

Popovic, Zoran; Knutsson, Per; Thaung, Jörgen; Owner-Petersen, Mette; Sjöstrand, Johan

2011-04-22

To demonstrate noninvasive imaging of human foveal capillary networks with a high-resolution, wide-field, dual-conjugate adaptive optics (DCAO) imaging instrument. The foveal capillary networks of five healthy subjects with no previous history of ocular or neurologic disease or surgery were imaged with a novel high-resolution, wide-field DCAO instrument. The foveal avascular zone (FAZ) in each image was defined using a manual procedure. An automated algorithm based on publicly available and custom-written software was used to identify vessels and extract morphologic FAZ and vessel parameters. Capillary densities were calculated in two annular regions of interest (ROIs) outside the FAZ (500 μm and 750 μm outer radius from the foveal center) and in the superior, inferior, temporal, and nasal quadrants within the two ROIs. Mean FAZ area was 0.302 ± 0.100 mm(2), and mean capillary density (length/area) in the inner ROI was 38.0 ± 4.0 mm(-1) and 36.4 ± 4.0 mm(-1) in the outer ROI. The difference in ROI capillary density was not significant. There was no significant difference in quadrant capillary density within the two ROIs or between quadrants irrespective of ROI. The authors have demonstrated a technique for noninvasive imaging and semiautomated detection and analysis of foveal capillaries. In comparison with other studies, their method yielded lower capillary densities than histology but similar results to the current clinical gold standard, fluorescein angiography. The increased field of view of the DCAO instrument opens up new possibilities for high-resolution noninvasive clinical imaging of foveal capillaries.

Ability and efficiency of an automatic analysis software to measure microvascular parameters.

PubMed

Carsetti, Andrea; Aya, Hollmann D; Pierantozzi, Silvia; Bazurro, Simone; Donati, Abele; Rhodes, Andrew; Cecconi, Maurizio

2017-08-01

Analysis of the microcirculation is currently performed offline, is time consuming and operator dependent. The aim of this study was to assess the ability and efficiency of the automatic analysis software CytoCamTools 1.7.12 (CC) to measure microvascular parameters in comparison with Automated Vascular Analysis (AVA) software 3.2. 22 patients admitted to the cardiothoracic intensive care unit following cardiac surgery were prospectively enrolled. Sublingual microcirculatory videos were analysed using AVA and CC software. The total vessel density (TVD) for small vessels, perfused vessel density (PVD) and proportion of perfused vessels (PPV) were calculated. Blood flow was assessed using the microvascular flow index (MFI) for AVA software and the averaged perfused speed indicator (APSI) for the CC software. The duration of the analysis was also recorded. Eighty-four videos from 22 patients were analysed. The bias between TVD-CC and TVD-AVA was 2.20 mm/mm 2 (95 % CI 1.37-3.03) with limits of agreement (LOA) of -4.39 (95 % CI -5.66 to -3.16) and 8.79 (95 % CI 7.50-10.01) mm/mm 2 . The percentage error (PE) for TVD was ±32.2 %. TVD was positively correlated between CC and AVA (r = 0.74, p < 0.001). The bias between PVD-CC and PVD-AVA was 6.54 mm/mm 2 (95 % CI 5.60-7.48) with LOA of -4.25 (95 % CI -8.48 to -0.02) and 17.34 (95 % CI 13.11-21.57) mm/mm 2 . The PE for PVD was ±61.2 %. PVD was positively correlated between CC and AVA (r = 0.66, p < 0.001). The median PPV-AVA was significantly higher than the median PPV-CC [97.39 % (95.25, 100 %) vs. 81.65 % (61.97, 88.99), p < 0.0001]. MFI categories cannot estimate or predict APSI values (p = 0.45). The time required for the analysis was shorter with CC than with AVA system [2'42″ (2'12″, 3'31″) vs. 16'12″ (13'38″, 17'57″), p < 0.001]. TVD is comparable between the two softwares, although faster with CC software. The values for PVD and PPV are not interchangeable given the different approach to assess microcirculatory flow.

Acoustic emission testing of composite vessels under sustained loading

NASA Technical Reports Server (NTRS)

Lark, R. F.; Moorhead, P. E.

1978-01-01

Acoustic emissions (AE) generated from Kevlar 49/epoxy composite pressure vessels subjected to sustained load-to-failure tests were studied. Data from two different transducer locations on the vessels were compared. It was found that AE from vessel wall-mounted transducers showed a wide variance from those for identical vessels subjected to the same pressure loading. Emissions from boss-mounted transducers did, however, yield values that were relatively consistent. It appears that the signals from the boss-mounted transducers represent an integrated average of the emissions generated by fibers fracturing during the vessel tests. The AE from boss-mounted transducers were also independent of time for vessel failure. This suggests that a similar number of fiber fractures must occur prior to initiation of vessel failure. These studies indicate a potential for developing an AE test procedure for predicting the residual service life or integrity of composite vessels.

Probabilistic retinal vessel segmentation

NASA Astrophysics Data System (ADS)

Wu, Chang-Hua; Agam, Gady

2007-03-01

Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

New generation cut-and-seal devices in oral and oropharyngeal cancer resection: clinical and cost-effectiveness study.

PubMed

Tirelli, G; Del Piero, G C; Valentinuz, G; Monte, A; Gatto, A; Rebelli, A; Quatela, E

2018-04-01

To evaluate the clinical efficacy and cost-effectiveness of ultrasonic shears and the electrothermal bipolar vessel sealing system, in comparison to the traditional cold knife and bipolar forceps, in oral and oropharyngeal cancer surgery. Patients who underwent oral or oropharyngeal cancer resection and neck dissection with either ultrasonic shears (n = 36) or electrothermal bipolar vessel sealing (n = 32) were enrolled. Surgical time, intra-operative bleeding, blood drainage, post-operative pain, neck oedema, complications and hospitalisation duration were compared to those of an historical cohort of 36 patients treated using a cold knife and bipolar forceps. Additionally, a cost-effectiveness evaluation was performed. Ultrasonic shears and, in particular, electrothermal bipolar vessel sealing, were advantageous compared to the traditional techniques. The cost of ultrasonic shears and electrothermal bipolar vessel sealing was completely offset by declining time-driven costs for the surgical team and operating theatre. Ultrasonic shears and, in particular, electrothermal bipolar vessel sealing, are more advantageous compared to the traditional techniques, from both a clinical and economic point of view.

Regulation of coronary blood flow during exercise.

PubMed

Duncker, Dirk J; Bache, Robert J

2008-07-01

Exercise is the most important physiological stimulus for increased myocardial oxygen demand. The requirement of exercising muscle for increased blood flow necessitates an increase in cardiac output that results in increases in the three main determinants of myocardial oxygen demand: heart rate, myocardial contractility, and ventricular work. The approximately sixfold increase in oxygen demands of the left ventricle during heavy exercise is met principally by augmenting coronary blood flow (~5-fold), as hemoglobin concentration and oxygen extraction (which is already 70-80% at rest) increase only modestly in most species. In contrast, in the right ventricle, oxygen extraction is lower at rest and increases substantially during exercise, similar to skeletal muscle, suggesting fundamental differences in blood flow regulation between these two cardiac chambers. The increase in heart rate also increases the relative time spent in systole, thereby increasing the net extravascular compressive forces acting on the microvasculature within the wall of the left ventricle, in particular in its subendocardial layers. Hence, appropriate adjustment of coronary vascular resistance is critical for the cardiac response to exercise. Coronary resistance vessel tone results from the culmination of myriad vasodilator and vasoconstrictors influences, including neurohormones and endothelial and myocardial factors. Unraveling of the integrative mechanisms controlling coronary vasodilation in response to exercise has been difficult, in part due to the redundancies in coronary vasomotor control and differences between animal species. Exercise training is associated with adaptations in the coronary microvasculature including increased arteriolar densities and/or diameters, which provide a morphometric basis for the observed increase in peak coronary blood flow rates in exercise-trained animals. In larger animals trained by treadmill exercise, the formation of new capillaries maintains capillary density at a level commensurate with the degree of exercise-induced physiological myocardial hypertrophy. Nevertheless, training alters the distribution of coronary vascular resistance so that more capillaries are recruited, resulting in an increase in the permeability-surface area product without a change in capillary numerical density. Maintenance of alpha- and ss-adrenergic tone in the presence of lower circulating catecholamine levels appears to be due to increased receptor responsiveness to adrenergic stimulation. Exercise training also alters local control of coronary resistance vessels. Thus arterioles exhibit increased myogenic tone, likely due to a calcium-dependent protein kinase C signaling-mediated alteration in voltage-gated calcium channel activity in response to stretch. Conversely, training augments endothelium-dependent vasodilation throughout the coronary microcirculation. This enhanced responsiveness appears to result principally from an increased expression of nitric oxide (NO) synthase. Finally, physical conditioning decreases extravascular compressive forces at rest and at comparable levels of exercise, mainly because of a decrease in heart rate. Impedance to coronary inflow due to an epicardial coronary artery stenosis results in marked redistribution of myocardial blood flow during exercise away from the subendocardium towards the subepicardium. However, in contrast to the traditional view that myocardial ischemia causes maximal microvascular dilation, more recent studies have shown that the coronary microvessels retain some degree of vasodilator reserve during exercise-induced ischemia and remain responsive to vasoconstrictor stimuli. These observations have required reassessment of the principal sites of resistance to blood flow in the microcirculation. A significant fraction of resistance is located in small arteries that are outside the metabolic control of the myocardium but are sensitive to shear and nitrovasodilators. The coronary collateral system embodies a dynamic network of interarterial vessels that can undergo both long- and short-term adjustments that can modulate blood flow to the dependent myocardium. Long-term adjustments including recruitment and growth of collateral vessels in response to arterial occlusion are time dependent and determine the maximum blood flow rates available to the collateral-dependent vascular bed during exercise. Rapid short-term adjustments result from active vasomotor activity of the collateral vessels. Mature coronary collateral vessels are responsive to vasodilators such as nitroglycerin and atrial natriuretic peptide, and to vasoconstrictors such as vasopressin, angiotensin II, and the platelet products serotonin and thromboxane A(2). During exercise, ss-adrenergic activity and endothelium-derived NO and prostanoids exert vasodilator influences on coronary collateral vessels. Importantly, alterations in collateral vasomotor tone, e.g., by exogenous vasopressin, inhibition of endogenous NO or prostanoid production, or increasing local adenosine production can modify collateral conductance, thereby influencing the blood supply to the dependent myocardium. In addition, vasomotor activity in the resistance vessels of the collateral perfused vascular bed can influence the volume and distribution of blood flow within the collateral zone. Finally, there is evidence that vasomotor control of resistance vessels in the normally perfused regions of collateralized hearts is altered, indicating that the vascular adaptations in hearts with a flow-limiting coronary obstruction occur at a global as well as a regional level. Exercise training does not stimulate growth of coronary collateral vessels in the normal heart. However, if exercise produces ischemia, which would be absent or minimal under resting conditions, there is evidence that collateral growth can be enhanced. In addition to ischemia, the pressure gradient between vascular beds, which is a determinant of the flow rate and therefore the shear stress on the collateral vessel endothelium, may also be important in stimulating growth of collateral vessels.

Assessing oxygen saturation in retinal vessels in high myopia patients pre- and post-implantable collamer lens implantation surgery.

PubMed

Chen, Pei; Cai, Xiaoxiao; Xu, Lijun; Zhang, Jing; Yang, Ying; Gao, Qianying; Ge, Jian; Yu, Keming; Zhuang, Jing

2017-09-01

To determine whether posterior chamber phakic implantable collamer lens (ICL) surgery in high myopia patients impedes oxygen saturation of retinal vessels. Mean oxygen saturation and diameter in retinal blood vessels were measured before and after ICL implantation surgery to correct high myopia refractive errors (i.e. -6.00 to -20.25 dioptres [D]), using an Oxymap T1 retinal oximeter. In 17 eyes of 17 patients, the Oxymap T1 retinal oximeter detected a small but significant decrease in oxygen saturation of retinal venules, 1-week postoperatively (compared to preoperative measurements). Moreover, at 1 week after ICL implantation, the diameter of patient retinal vessels had consistently contracted, compared to preoperative measurements. By 1 month after ICL surgery, however, both the oxygen saturation and retinal vessel diameter had returned to preoperative levels. Otherwise, no statistically significant difference in oxygen saturation and diameter of retinal arterioles was found when comparing their measurements before and 1 week after implantation. Stable levels of oxygen saturation in retinal vessels, as detected by the Oxymap T1 oximeter, show ICL implantation would not leave lasting impact or adverse effects to retina oxygen saturation in high myopia patients. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

The application of probabilistic fracture analysis to residual life evaluation of embrittled reactor vessels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickson, T.L.; Simonen, F.A.

1992-05-01

Probabilistic fracture mechanics analysis is a major element of comprehensive probabilistic methodology on which current NRC regulatory requirements for pressurized water reactor vessel integrity evaluation are based. Computer codes such as OCA-P and VISA-II perform probabilistic fracture analyses to estimate the increase in vessel failure probability that occurs as the vessel material accumulates radiation damage over the operating life of the vessel. The results of such analyses, when compared with limits of acceptable failure probabilities, provide an estimation of the residual life of a vessel. Such codes can be applied to evaluate the potential benefits of plant-specific mitigating actions designedmore » to reduce the probability of failure of a reactor vessel. 10 refs.« less

The application of probabilistic fracture analysis to residual life evaluation of embrittled reactor vessels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickson, T.L.; Simonen, F.A.

1992-01-01

Probabilistic fracture mechanics analysis is a major element of comprehensive probabilistic methodology on which current NRC regulatory requirements for pressurized water reactor vessel integrity evaluation are based. Computer codes such as OCA-P and VISA-II perform probabilistic fracture analyses to estimate the increase in vessel failure probability that occurs as the vessel material accumulates radiation damage over the operating life of the vessel. The results of such analyses, when compared with limits of acceptable failure probabilities, provide an estimation of the residual life of a vessel. Such codes can be applied to evaluate the potential benefits of plant-specific mitigating actions designedmore » to reduce the probability of failure of a reactor vessel. 10 refs.« less

Preliminary clinical evaluation of automated analysis of the sublingual microcirculation in the assessment of patients with septic shock: Comparison of automated versus semi-automated software.

PubMed

Sharawy, Nivin; Mukhtar, Ahmed; Islam, Sufia; Mahrous, Reham; Mohamed, Hassan; Ali, Mohamed; Hakeem, Amr A; Hossny, Osama; Refaa, Amera; Saka, Ahmed; Cerny, Vladimir; Whynot, Sara; George, Ronald B; Lehmann, Christian

2017-01-01

The outcome of patients in septic shock has been shown to be related to changes within the microcirculation. Modern imaging technologies are available to generate high resolution video recordings of the microcirculation in humans. However, evaluation of the microcirculation is not yet implemented in the routine clinical monitoring of critically ill patients. This is mainly due to large amount of time and user interaction required by the current video analysis software. The aim of this study was to validate a newly developed automated method (CCTools®) for microcirculatory analysis of sublingual capillary perfusion in septic patients in comparison to standard semi-automated software (AVA3®). 204 videos from 47 patients were recorded using incident dark field (IDF) imaging. Total vessel density (TVD), proportion of perfused vessels (PPV), perfused vessel density (PVD), microvascular flow index (MFI) and heterogeneity index (HI) were measured using AVA3® and CCTools®. Significant differences between the numeric results obtained by the two different software packages were observed. The values for TVD, PVD and MFI were statistically related though. The automated software technique successes to show septic shock induced microcirculation alterations in near real time. However, we found wide degrees of agreement between AVA3® and CCTools® values due to several technical factors that should be considered in the future studies.

Impact of plasma viscosity on microcirculatory flow after traumatic haemorrhagic shock: A prospective observational study.

PubMed

Naumann, David N; Hazeldine, Jon; Bishop, Jon; Midwinter, Mark J; Harrison, Paul; Nash, Gerard; Hutchings, Sam D

2018-05-19

Preclinical studies report that higher plasma viscosity improves microcirculatory flow after haemorrhagic shock and resuscitation, but no clinical study has tested this hypothesis. We investigated the relationship between plasma viscosity and sublingual microcirculatory flow in patients during resuscitation for traumatic haemorrhagic shock (THS). Sublingual video-microscopy was performed for 20 trauma patients with THS as soon as feasible in hospital, and then at 24 h and 48 h. Values were obtained for total vessel density, perfused vessel density, proportion of perfused vessels, microcirculatory flow index (MFI), microcirculatory heterogeneity index (MHI), and Point of Care Microcirculation (POEM) scores. Plasma viscosity was measured using a Wells-Brookfield cone and plate micro-viscometer. Logistic regression analyses examined relationships between microcirculatory parameters and plasma viscosity, adjusting for covariates (systolic blood pressure, heart rate, haematocrit, rate and volume of fluids, and rate of noradrenaline). Higher plasma viscosity was not associated with improved microcirculatory parameters. Instead, there were weakly significant associations between higher plasma viscosity and lower (poorer) MFI (p = 0.040), higher (worse) MHI (p = 0.033), and lower (worse) POEM scores (p = 0.039). The current study did not confirm the hypothesis that higher plasma viscosity improves microcirculatory flow dynamics in patients with THS. Further clinical investigations are warranted to determine whether viscosity is a physical parameter of importance during resuscitation of these patients.

Evaluation on the Feasibility of Using Ultrasonic Testing of Reactor Pressure Vessel Welds for Assessing Flaw Density/Distribution per 10 CFR 50.61a, Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, Edmund J.; Anderson, Michael T.

2014-06-10

This technical letter report provides the status of an assessment undertaken by PNNL at the request of the NRC to verify the capability of periodic ASME-required volumetric examinations of reactor vessels to characterize the density and distribution of flaws of interest for applying §50.61a on a plant-by-plant basis. The PTS rule, described in the Code of Federal Regulations, Title 10, Section 50.61 (§50.61), "Fracture Toughness Requirements for Protection against Pressurized Thermal Shock Events," establishes screening criteria to ensure that the potential for a reactor vessel to fail due to a PTS event is deemed to be acceptably low. Recently, themore » NRC completed a research program that concluded that the risk of through-wall cracking due to a PTS event is much lower than previously estimated. The NRC subsequently developed and promulgated an alternate PTS rule, §50.61a, that can be implemented by PWR licensees. The §50.61a rule differs from §50.61 in that it requires licensees who choose to follow this alternate method to analyze the results from periodic volumetric examinations required by the ASME Code, Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plants.« less

Soliton driven angiogenesis

NASA Astrophysics Data System (ADS)

Bonilla, L. L.; Carretero, M.; Terragni, F.; Birnir, B.

2016-08-01

Angiogenesis is a multiscale process by which blood vessels grow from existing ones and carry oxygen to distant organs. Angiogenesis is essential for normal organ growth and wounded tissue repair but it may also be induced by tumours to amplify their own growth. Mathematical and computational models contribute to understanding angiogenesis and developing anti-angiogenic drugs, but most work only involves numerical simulations and analysis has lagged. A recent stochastic model of tumour-induced angiogenesis including blood vessel branching, elongation, and anastomosis captures some of its intrinsic multiscale structures, yet allows one to extract a deterministic integropartial differential description of the vessel tip density. Here we find that the latter advances chemotactically towards the tumour driven by a soliton (similar to the famous Korteweg-de Vries soliton) whose shape and velocity change slowly. Analysing these collective coordinates paves the way for controlling angiogenesis through the soliton, the engine that drives this process.

Comparison of the number of gingival blood vessels between type 2 diabetes mellitus and chronic periodontitis patients: An immunohistological study

PubMed Central

Penmetsa, Gautami Subhadra; Baddam, Satyanarayana; Manyam, Ravikanth; Dwarakanath, Chinni Doraswamy

2015-01-01

Background: The relationship between diabetes and periodontitis has been studied for more than 50 years and is generally agreed that the periodontal disease is more prevalent in diabetic patients compared to nondiabetics. Vascular changes like increased thickness of basement membrane in small vessels has been reported in diabetic patients, but the quantity of blood vessels in gingiva of diabetic patients has not been discussed much. The aim of this study was to compare the number of blood vessels in gingiva between chronic periodontitis (CP) patients, CP with diabetes (type 2), and normal healthy gingiva. Materials and Methods: The study included 75 patients, divided into three groups of 25 patients each-Group I with healthy periodontium (HP), Group II with CP, and Group III with CP with diabetes mellitus (CPDM). Gingival biopsies were obtained from the subjects undergoing crown lengthening procedure for Group I, and in patients with CP and in CPDM biopsies were collected from teeth undergoing extraction. Sections were prepared for immune histochemical staining with CD34. Results: Difference was observed in the average number of blood vessels when compared between HP, CP, and CPDM groups. Statistical significant difference was observed when the HP and CP groups and HP and CPDM groups were compared. Conclusion: The results of the study indicated that the number of blood vessels in gingival connective tissue is significantly higher in CP and CPDM patients. PMID:26015666

Increasing Vero viable cell densities for yellow fever virus production in stirred-tank bioreactors using serum-free medium.

PubMed

Mattos, Diogo A; Silva, Marlon V; Gaspar, Luciane P; Castilho, Leda R

2015-08-20

In this work, changes in Vero cell cultivation methods have been employed in order to improve cell growth conditions to obtain higher viable cell densities and to increase viral titers. The propagation of the 17DD yellow fever virus (YFV) in Vero cells grown on Cytodex I microcarriers was evaluated in 3-L bioreactor vessels. Prior to the current changes, Vero cells were repeatedly displaying insufficient microcarrier colonization. A modified cultivation process with four changes has resulted in higher cell densities and higher virus titers than previously observed for 17DD YFV. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biglycan potentially regulates angiogenesis during fracture repair by altering expression and function of endostatin

PubMed Central

Myren, Maja; Kirby, David J.; Noonan, Megan L.; Maeda, Azusa; Owens, Rick T.; Ricard-Blum, Sylvie; Kram, Vardit; Kilts, Tina M.; Young, Marian F.

2016-01-01

The small proteoglycan biglycan (Bgn) is highly expressed in the organic matrix of bone and plays a role in bone formation. Previous work implicated Bgn in vessel growth during bone healing (1). By infusing barium sulfate (BaSO4) into WT and Bgn-deficient mice we discovered the positive effect of Bgn in modulating angiogenesis during fracture healing. Using micro-computed tomography angiography we found significant differences in the vessel size and volume among other parameters. To further understand the mechanistic basis for this, we explored the relationship between Bgn and the anti-angiogenic protein endostatin. Immunohistochemistry (IHC) showed co-localization of Bgn and endostatin in regions of bone formation, with increased endostatin staining in Bgn-KO compared to WT at 14 days post-fracture. To further elucidate the relationship between Bgn and endostatin, an endothelial cell tube formation assay was used. This study showed that endothelial cells treated with endostatin had significantly decreased vessel length and vessel branches compared to untreated cells, while cells treated with endostatin and Bgn at a 1:1 molar ratio had vessel length and vessel branches comparable to untreated cells. This indicated that Bgn was able to mitigate the inhibitory effect of endostatin on endothelial cell growth. In summary, these results suggest that Bgn is needed for proper blood vessel formation during fracture healing, and one mechanism by which Bgn impacts angiogenesis is through inhibition of endostatin. PMID:27072616

Nuclear reactor construction with bottom supported reactor vessel

DOEpatents

Sharbaugh, John E.

1987-01-01

An improved liquid metal nuclear reactor construction has a reactor core and a generally cylindrical reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core within the pool. The reactor vessel has an open top end, a closed flat bottom end wall and a continuous cylindrical closed side wall interconnecting the top end and bottom end wall. The reactor also has a generally cylindrical concrete containment structure surrounding the reactor vessel and being formed by a cylindrical side wall spaced outwardly from the reactor vessel side wall and a flat base mat spaced below the reactor vessel bottom end wall. A central support pedestal is anchored to the containment structure base mat and extends upwardly therefrom to the reactor vessel and upwardly therefrom to the reactor core so as to support the bottom end wall of the reactor vessel and the lower end of the reactor core in spaced apart relationship above the containment structure base mat. Also, an annular reinforced support structure is disposed in the reactor vessel on the bottom end wall thereof and extends about the lower end of the core so as to support the periphery thereof. In addition, an annular support ring having a plurality of inward radially extending linear members is disposed between the containment structure base mat and the bottom end of the reactor vessel wall and is connected to and supports the reactor vessel at its bottom end on the containment structure base mat so as to allow the reactor vessel to expand radially but substantially prevent any lateral motions that might be imposed by the occurrence of a seismic event. The reactor construction also includes a bed of insulating material in sand-like granular form, preferably being high density magnesium oxide particles, disposed between the containment structure base mat and the bottom end wall of the reactor vessel and uniformly supporting the reactor vessel at its bottom end wall on the containment structure base mat so as to insulate the reactor vessel bottom end wall from the containment structure base mat and allow the reactor vessel bottom end wall to freely expand as it heats up while providing continuous support thereof. Further, a deck is supported upon the side wall of the containment structure above the top open end of the reactor vessel, and a plurality of serially connected extendible and retractable annular bellows extend between the deck and the top open end of the reactor vessel and flexibly and sealably interconnect the reactor vessel at its top end to the deck. An annular guide ring is disposed on the containment structure and extends between its side wall and the top open end of the reactor vessel for providing lateral support of the reactor vessel top open end by limiting imposition of lateral loads on the annular bellows by the occurrence of a lateral seismic event.

Evaluation of macular and peripapillary vessel flow density in eyes with no known pathology using optical coherence tomography angiography.

PubMed

Hassan, Muhammad; Sadiq, Mohammad Ali; Halim, Muhammad Sohail; Afridi, Rubbia; Soliman, Mohamed K; Sarwar, Salman; Agarwal, Aniruddha; Do, Diana V; Nguyen, Quan Dong; Sepah, Yasir Jamal

2017-01-01

To assess normal vessel flow density (VFD) in macular and peripapillary regions of eyes with no known ocular pathology using optical coherence tomography angiography (OCTA). AngioVue (Optovue, Fremont, CA, USA) was used to capture OCTA images. A 3 × 3 mm grid and a 4.5 × 4.5 mm grid was used to scan parafoveal and peripapillary regions, respectively. ReVue software was utilized to measure VFD in five sectors within the inner two circles of ETDRS grid in macular region and correlated to retinal thickness of same sectors. At optic disc, VFD was calculated in six sectors based on Garway-Heath map. Area and morphology of foveal avascular zone (FAZ) was correlated with VFD in central 1 mm. The influence of myopia on mean VFD was also assessed. Twenty-four eyes (mean age: 30 years) were analyzed. Mean VFD in macular sectors was 43.5 (±4.5) and 45.8 (±5.0) % in superficial and deep retinal plexuses, respectively. Mean VFD was significantly higher in deep retinal plexus compared to superficial retinal plexus in all sectors except central 1 mm (p < 0.05). Mean VFD in central 1 mm increases with an increase in central retinal thickness in both superficial and deep retinal plexuses (p < 0.001). Mean parafoveal VFD at level of both superficial and deep retinal plexuses decrease with an increase in spherical equivalent in myopics (p < 0.05). Mean VFD in myopics was found to be significantly lower in parafoveal region of deep retinal plexus (p < 0.05). Mean area of FAZ was 0.33 (±0.15) and 0.47 mm 2 (±0.15) in superficial and deep retinal plexuses, respectively. Area of FAZ decreases with an increase in central 1 mm thickness and foveal VFD (p < 0.001). OCTA may be used to measure VFD in macular and peripapillary regions. Vessels in the parafoveal region are more densely packed in the deep retinal plexus leading to higher VFD compared to superficial plexus. Thicker retina in fovea translates into higher foveal VFD due to more compact arrangement of retinal layers and continuity of inner nuclear layer (INL). Myopia is associated with lower VFD in parafoveal region at level of deep retinal plexuses which may explain thinning of INL in myopics.

Growth of arterioles in chronically stimulated adult rat skeletal muscle.

PubMed

Hansen-Smith, F; Egginton, S; Hudlicka, O

1998-01-01

The purpose of this study was to test the hypothesis that capillary growth induced by chronic electrical stimulation of skeletal muscle is accompanied by the growth of small arterioles. Lower limb flexor muscles of Sprague-Dawley rats were stimulated by electrodes implanted in the vicinity of the peroneal nerve at 10 Hz for 8 h/d for 2 and 7 days. Cryostat sections from the proximal, middle, and distal regions of the extensor digitorum longus muscle (EDL) were fluorescently immunolabeled with alpha-smooth muscle actin (alpha SMA) and myosin heavy chain (MHC) to identify mature (alpha SMA and MHC-positive) and immature (alpha SMA-positive, MHC-negative) arterioles. The fluorescent derivative of the lectin Griffonia simplicifolia I (GSI) was used to identify all microvessels, including arterioles, capillaries, and venules. The number of vessels positive for GSI or alpha SMA surrounding muscle fibers was similar in all three muscle regions (proximal, middle, distal). The mean values +/- SEM for GSI-positive vessels from all regions were similar in control (4.3 +/- 0.07) and 2-day stimulated (4.7 +/- 0.08) but higher in 7-day stimulated muscles (6.7 +/- 0.1, p < 0.05), thus confirming the previous findings on capillary growth. A similar increase was found in the number of alpha SMA positive vessels < or = 10 microns outer diameter (1.3 +/- 0.09 versus 0.4 +/- 0.03 around muscle fibers in controls). The density of terminal arterioles (< or = 10 microns) was slightly but not significantly higher after 2 days of stimulation (19.5 +/- 4 versus 15.6 +/- 2 profiles/mm2 in control muscles) and significantly higher after 7 days (33 +/- 7). While a similar increase was observed in the density of preterminal arterioles > 10 microns (17 +/- 3 control, 22 +/- 3 at 2 days and 40 +/- 5 at 7 days), the density of MHC-positive vessels muscles stimulated for 7 days was unchanged. Seven-day stimulated muscle also had a fivefold higher density of microvessel profiles < or = 10 microns that were only partially surrounded by alpha SMA. This considerably exceeds the relative increase in the number of capillaries and thus supports the concept of arteriolar growth by transformation from capillaries. Chronic electrical stimulation results in an early increase in the number of immature (MHG-negative), but not mature (MHC-positive) arterioles, a process that accompanies the increase in capillarization. The great increase in the number of microvessels only partially covered by alpha SMA suggests arteriolization of capillaries as a contributing mechanism in this growth.

Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death.

PubMed

Colangelo, Michele; Camarero, Jesús J; Borghetti, Marco; Gazol, Antonio; Gentilesca, Tiziana; Ripullone, Francesco

2017-01-01

Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees.

Hyperintense Vessels on T2-PROPELLER-FLAIR in Patients with Acute MCA Stroke: Prediction of Arterial Stenosis and Perfusion Abnormality.

PubMed

Ahn, S J; Suh, S H; Lee, K-Y; Kim, J H; Seo, K-D; Lee, S

2015-11-01

Fluid-attenuated inversion recovery hyperintense vessels in stroke represent leptomeningeal collateral flow. We presumed that FLAIR hyperintense vessels would be more closely associated with arterial stenosis and perfusion abnormality in ischemic stroke on T2-PROPELLER-FLAIR than on T2-FLAIR. We retrospectively reviewed 35 patients with middle cerebral territorial infarction who underwent MR imaging. FLAIR hyperintense vessel scores were graded according to the number of segments with FLAIR hyperintense vessels in the MCA ASPECTS areas. We compared the predictability of FLAIR hyperintense vessels between T2-PROPELLER-FLAIR and T2-FLAIR for large-artery stenosis. The interagreement between perfusion abnormality and FLAIR hyperintense vessels was assessed. In subgroup analysis (9 patients with MCA horizontal segment occlusion), the association of FLAIR hyperintense vessels with ischemic lesion volume and perfusion abnormality volume was evaluated. FLAIR hyperintense vessel scores were significantly higher on T2-PROPELLER-FLAIR than on T2-FLAIR (3.50 ± 2.79 versus 1.21 ± 1.47, P < .01), and the sensitivity for large-artery stenosis was significantly improved on T2-PROPELLER-FLAIR (93% versus 68%, P = .03). FLAIR hyperintense vessels on T2-PROPELLER-FLAIR were more closely associated with perfusion abnormalities than they were on T2-FLAIR (κ = 0.64 and κ = 0.27, respectively). In subgroup analysis, FLAIR hyperintense vessels were positively correlated with ischemic lesion volume on T2-FLAIR, while the mismatch of FLAIR hyperintense vessels between the 2 sequences was negatively correlated with ischemic lesion volume (P = .01). In MCA stroke, FLAIR hyperintense vessels were more prominent on T2-PROPELLER-FLAIR compared with T2-FLAIR. In addition, FLAIR hyperintense vessels on T2-PROPELLER-FLAIR have a significantly higher sensitivity for predicting large-artery stenosis than they do on T2-FLAIR. Moreover, the areas showing FLAIR hyperintense vessels on T2-PROPELLER-FLAIR were more closely associated with perfusion abnormality than those on T2-FLAIR. © 2015 by American Journal of Neuroradiology.

Constructing a High Density Cell Culture System

NASA Technical Reports Server (NTRS)

Spaulding, Glenn F. (Inventor)

1996-01-01

An annular culture vessel for growing mammalian cells is constructed in a one piece integral and annular configuration with an open end which is closed by an endcap. The culture vessel is rotatable about a horizontal axis by use of conventional roller systems commonly used in culture laboratories. The end wall of the endcap has tapered access ports to frictionally and sealingly receive the ends of hypodermic syringes. The syringes permit the introduction of fresh nutrient and withdrawal of spent nutrients. The walls are made of conventional polymeric cell culture material and are subjected to neutron bombardment to form minute gas permeable perforations in the walls.

Angiographic Validation of the American College of Cardiology Foundation–The Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategies Study

PubMed Central

Chakrabarti, Anjan K.; Grau-Sepulveda, Maria V.; O’Brien, Sean; Abueg, Cassandra; Ponirakis, Angelo; Delong, Elizabeth; Peterson, Eric; Klein, Lloyd W.; Garratt, Kirk N.; Weintraub, William S.; Gibson, C. Michael

2017-01-01

Background The goal of this study was to compare angiographic interpretation of coronary arteriograms by sites in community practice versus those made by a centralized angiographic core laboratory. Methods and Results The study population consisted of 2013 American College of Cardiology–National Cardiovascular Data Registry (ACC–NCDR) records with 2- and 3- vessel coronary disease from 54 sites in 2004 to 2007. The primary analysis compared Registry (NCDR)-defined 2- and 3-vessel disease versus those from an angiographic core laboratory analysis. Vessel-level kappa coefficients suggested moderate agreement between NCDR and core laboratory analysis, ranging from kappa=0.39 (95% confidence intervals, 0.32–0.45) for the left anterior descending artery to kappa=0.59 (95% confidence intervals, 0.55–0.64) for the right coronary artery. Overall, 6.3% (n=127 out of 2013) of those patients identified with multivessel disease at NCDR sites had had 0- or 1-vessel disease by core laboratory reading. There was no directional bias with regard to overcall, that is, 12.3% of cases read as 3-vessel disease by the sites were read as <3-vessel disease by the core laboratory, and 13.9% of core laboratory 3-vessel cases were read as <3-vessel by the sites. For a subset of patients with left main coronary disease, registry overcall was not linked to increased rates of mortality or myocardial infarction. Conclusions There was only modest agreement between angiographic readings in clinical practice and those from an independent core laboratory. Further study will be needed because the implications for patient management are uncertain. PMID:24496239

Angiographic validation of the American College of Cardiology Foundation-the Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategies study.

PubMed

Chakrabarti, Anjan K; Grau-Sepulveda, Maria V; O'Brien, Sean; Abueg, Cassandra; Ponirakis, Angelo; Delong, Elizabeth; Peterson, Eric; Klein, Lloyd W; Garratt, Kirk N; Weintraub, William S; Gibson, C Michael

2014-02-01

The goal of this study was to compare angiographic interpretation of coronary arteriograms by sites in community practice versus those made by a centralized angiographic core laboratory. The study population consisted of 2013 American College of Cardiology-National Cardiovascular Data Registry (ACC-NCDR) records with 2- and 3- vessel coronary disease from 54 sites in 2004 to 2007. The primary analysis compared Registry (NCDR)-defined 2- and 3-vessel disease versus those from an angiographic core laboratory analysis. Vessel-level kappa coefficients suggested moderate agreement between NCDR and core laboratory analysis, ranging from kappa=0.39 (95% confidence intervals, 0.32-0.45) for the left anterior descending artery to kappa=0.59 (95% confidence intervals, 0.55-0.64) for the right coronary artery. Overall, 6.3% (n=127 out of 2013) of those patients identified with multivessel disease at NCDR sites had had 0- or 1-vessel disease by core laboratory reading. There was no directional bias with regard to overcall, that is, 12.3% of cases read as 3-vessel disease by the sites were read as <3-vessel disease by the core laboratory, and 13.9% of core laboratory 3-vessel cases were read as <3-vessel by the sites. For a subset of patients with left main coronary disease, registry overcall was not linked to increased rates of mortality or myocardial infarction. There was only modest agreement between angiographic readings in clinical practice and those from an independent core laboratory. Further study will be needed because the implications for patient management are uncertain.

Impact of The Protective Renin-Angiotensin System (RAS) on The Vasoreparative Function of CD34+ CACs in Diabetic Retinopathy

NASA Technical Reports Server (NTRS)

Duan, Yaqian; Moldovan, Leni; Miller, Rehae C.; Beli, Eleni; Salazar, Tatiana; Hazra, Sugata; Al-Sabah, Jude; Chalam, KV; Raghunandan, Sneha; Vyas, Ruchi;

Doxorubicin loaded superparamagnetic PLGA-iron oxide multifunctional microbubbles for dual-mode US/MR imaging and therapy of metastasis in lymph nodes.

PubMed

Niu, Chengcheng; Wang, Zhigang; Lu, Guangming; Krupka, Tianyi M; Sun, Yang; You, Yufang; Song, Weixiang; Ran, Haitao; Li, Pan; Zheng, Yuanyi

2013-03-01

Current strategies for tumor-induced sentinel lymph node detection and metastasis therapy have limitations. In this work, we co-encapsulated iron oxide nanoparticles and chemotherapeutic drug into poly(lactic-co-glycolic acid) (PLGA) microbubbles to form multifunctional polymer microbubbles (MPMBs) for both tumor lymph node imaging and therapy. Fe(3)O(4) nanoparticles and doxorubicin (DOX) co-encapsulated PLGA microbubbles were prepared and filled with perfluorocarbon gas. Enhancement of ultrasound (US)/magnetic resonance (MR) imaging and US triggered drug delivery were evaluated both in vitro and in vivo. The MPMBs exhibited characters like narrow size distribution and smooth surface with a mean diameter of 868.0 ± 68.73 nm. In addition, varying the concentration of Fe(3)O(4) nanoparticles in the bubbles did not significantly influence the DOX encapsulation efficiency or drug loading efficiency. Our in vitro results demonstrated that these MPMBs could enhance both US and MR imaging which was further validated in vivo showing that these MPMBs enhanced tumor lymph nodes signals. The anti-tumor effect of MPMBs mediated chemotherapy was assessed in vivo using end markers like tumor proliferation index, micro blood vessel density and micro lymphatic vessel density, which were shown consistently the lowest after the MPMBs plus sonication treatment compared to controls. In line with these findings, the tumor cell apoptotic index was found the largest after the MPMBs plus sonication treatment. In conclusion, we have successfully developed a doxorubicin loaded superparamagnetic PLGA-Iron Oxide multifunctional theranostic agent for dual-mode US/MR Imaging of lymph node, and for low frequency US triggered therapy of metastasis in lymph nodes, which might provide a strategy for the imaging and chemotherapy of primary tumor and their metastases. Copyright © 2012 Elsevier Ltd. All rights reserved.

Study on the Characteristics of Contrast-Enhanced Ultrasound and Its Utility in Assessing the Microvessel Density in Ovarian Tumors or Tumor-Like Lesions

PubMed Central

Wang, Junyan; Lv, Faqin; Fei, Xiang; Cui, Qiuli; Wang, Longxia; Gao, Xuewen; Yuan, Zhixian; Lin, Qian; Lv, Yali; Liu, Aijun

2011-01-01

Angiogenesis is a critical factor in tumor growth and metastasis, and microvessel density (MVD) was an important parameter for assessing vessels in tumors. However, radiologic assessment of tumor vascularity is not yet well established. In our study, we aimed at investigating the efficacy of contrast-enhanced ultrasonography (CEUS) in exploring the vascularity of the ovarian tumors or tumor-like lesions to assess the relationship between the parameters of the peak intensity (PI) and area under curve (AUC) on CEUS and MVD in ovarian masses. Compared to the contrast-enhanced ultrasound technique, conventional ultrasound shows limitation in differentiating benign and malignant ovarian tumors. The former is promising in improving the sensitivity of detecting small vessels and blood flow in ovarian tumors. Our results showed clear differences in enhancement patterns between benign and malignant ovary tumors or tumor-like lesions. The PI and AUC in the malignant tumors were significantly higher than those in the benign tumors or tumor-like lesions (p=0.001 and =0.01, respectively). The MVD was 43.1 ± 20.4 in the benign tumors or tumor-like lesions and was 65.3 ± 22.3 in the malignant ones (p= 0.01). In both the benign and malignant groups, the PI and AUC were correlated significantly with the MVD (r=0.595, p = 0.001; r =0.533, p = 0.003, respectively). The PI and AUC in CEUS can reflect the MVD in ovarin tumors. The PI and AUC of the ovarian masses in the contrast transvaginal sonography show significant correlation with the angiogenesis and may help in assessing tumor vascularity in ovarian masses. PMID:21614152

A three-dimensional strain measurement method in elastic transparent materials using tomographic particle image velocimetry

PubMed Central

Suzuki, Sara; Aoyama, Yusuke; Umezu, Mitsuo

2017-01-01

Background The mechanical interaction between blood vessels and medical devices can induce strains in these vessels. Measuring and understanding these strains is necessary to identify the causes of vascular complications. This study develops a method to measure the three-dimensional (3D) distribution of strain using tomographic particle image velocimetry (Tomo-PIV) and compares the measurement accuracy with the gauge strain in tensile tests. Methods and findings The test system for measuring 3D strain distribution consists of two cameras, a laser, a universal testing machine, an acrylic chamber with a glycerol water solution for adjusting the refractive index with the silicone, and dumbbell-shaped specimens mixed with fluorescent tracer particles. 3D images of the particles were reconstructed from 2D images using a multiplicative algebraic reconstruction technique (MART) and motion tracking enhancement. Distributions of the 3D displacements were calculated using a digital volume correlation. To evaluate the accuracy of the measurement method in terms of particle density and interrogation voxel size, the gauge strain and one of the two cameras for Tomo-PIV were used as a video-extensometer in the tensile test. The results show that the optimal particle density and interrogation voxel size are 0.014 particles per pixel and 40 × 40 × 40 voxels with a 75% overlap. The maximum measurement error was maintained at less than 2.5% in the 4-mm-wide region of the specimen. Conclusions We successfully developed a method to experimentally measure 3D strain distribution in an elastic silicone material using Tomo-PIV and fluorescent particles. To the best of our knowledge, this is the first report that applies Tomo-PIV to investigate 3D strain measurements in elastic materials with large deformation and validates the measurement accuracy. PMID:28910397

Endothelial fibroblast growth factor receptor signaling is required for vascular remodeling following cardiac ischemia-reperfusion injury

PubMed Central

Castro, Angela M.; Lupu, Traian S.; Weinheimer, Carla; Smith, Craig; Kovacs, Attila

2016-01-01

Fibroblast growth factor (FGF) signaling is cardioprotective in various models of myocardial infarction. FGF receptors (FGFRs) are expressed in multiple cell types in the adult heart, but the cell type-specific FGFR signaling that mediates different cardioprotective endpoints is not known. To determine the requirement for FGFR signaling in endothelium in cardiac ischemia-reperfusion injury, we conditionally inactivated the Fgfr1 and Fgfr2 genes in endothelial cells with Tie2-Cre (Tie2-Cre, Fgfr1f/f, Fgfr2f/f DCKO mice). Tie2-Cre, Fgfr1f/f, Fgfr2f/f DCKO mice had normal baseline cardiac morphometry, function, and vessel density. When subjected to closed-chest, regional cardiac ischemia-reperfusion injury, Tie2-Cre, Fgfr1f/f, Fgfr2f/f DCKO mice showed a significantly increased hypokinetic area at 7 days, but not 1 day, after reperfusion. Tie2-Cre, Fgfr1f/f, Fgfr2f/f DCKO mice also showed significantly worsened cardiac function compared with controls at 7 days but not 1 day after reperfusion. Pathophysiological analysis showed significantly decreased vessel density, increased endothelial cell apoptosis, and worsened tissue hypoxia in the peri-infarct area at 7 days following reperfusion. Notably, Tie2-Cre, Fgfr1f/f, Fgfr2f/f DCKO mice showed no impairment in the cardiac hypertrophic response. These data demonstrate an essential role for FGFR1 and FGFR2 in endothelial cells for cardiac functional recovery and vascular remodeling following in vivo cardiac ischemia-reperfusion injury, without affecting the cardiac hypertrophic response. This study suggests the potential for therapeutic benefit from activation of endothelial FGFR pathways following ischemic injury to the heart. PMID:26747503

Endothelial fibroblast growth factor receptor signaling is required for vascular remodeling following cardiac ischemia-reperfusion injury.

PubMed

House, Stacey L; Castro, Angela M; Lupu, Traian S; Weinheimer, Carla; Smith, Craig; Kovacs, Attila; Ornitz, David M

2016-03-01

Fibroblast growth factor (FGF) signaling is cardioprotective in various models of myocardial infarction. FGF receptors (FGFRs) are expressed in multiple cell types in the adult heart, but the cell type-specific FGFR signaling that mediates different cardioprotective endpoints is not known. To determine the requirement for FGFR signaling in endothelium in cardiac ischemia-reperfusion injury, we conditionally inactivated the Fgfr1 and Fgfr2 genes in endothelial cells with Tie2-Cre (Tie2-Cre, Fgfr1(f/f), Fgfr2(f/f) DCKO mice). Tie2-Cre, Fgfr1(f/f), Fgfr2(f/f) DCKO mice had normal baseline cardiac morphometry, function, and vessel density. When subjected to closed-chest, regional cardiac ischemia-reperfusion injury, Tie2-Cre, Fgfr1(f/f), Fgfr2(f/f) DCKO mice showed a significantly increased hypokinetic area at 7 days, but not 1 day, after reperfusion. Tie2-Cre, Fgfr1(f/f), Fgfr2(f/f) DCKO mice also showed significantly worsened cardiac function compared with controls at 7 days but not 1 day after reperfusion. Pathophysiological analysis showed significantly decreased vessel density, increased endothelial cell apoptosis, and worsened tissue hypoxia in the peri-infarct area at 7 days following reperfusion. Notably, Tie2-Cre, Fgfr1(f/f), Fgfr2(f/f) DCKO mice showed no impairment in the cardiac hypertrophic response. These data demonstrate an essential role for FGFR1 and FGFR2 in endothelial cells for cardiac functional recovery and vascular remodeling following in vivo cardiac ischemia-reperfusion injury, without affecting the cardiac hypertrophic response. This study suggests the potential for therapeutic benefit from activation of endothelial FGFR pathways following ischemic injury to the heart. Copyright © 2016 the American Physiological Society.

Low Immunogenic Endothelial Cells Maintain Morphological and Functional Properties Required for Vascular Tissue Engineering.

PubMed

Lau, Skadi; Eicke, Dorothee; Carvalho Oliveira, Marco; Wiegmann, Bettina; Schrimpf, Claudia; Haverich, Axel; Blasczyk, Rainer; Wilhelmi, Mathias; Figueiredo, Constança; Böer, Ulrike

2018-03-01

The limited availability of native vessels suitable for the application as hemodialysis shunts or bypass material demands new strategies in cardiovascular surgery. Tissue-engineered vascular grafts containing autologous cells are considered ideal vessel replacements due to the low risk of rejection. However, endothelial cells (EC), which are central components of natural blood vessels, are difficult to obtain from elderly patients of poor health. Umbilical cord blood represents a promising alternative source for EC, but their allogeneic origin corresponds with the risk of rejection after allotransplantation. To reduce this risk, the human leukocyte antigen class I (HLA I) complex was stably silenced by lentiviral vector-mediated RNA interference (RNAi) in EC from peripheral blood and umbilical cord blood and vein. EC from all three sources were transduced by 93.1% ± 4.8% and effectively, HLA I-silenced by up to 67% compared to nontransduced (NT) cells or transduced with a nonspecific short hairpin RNA, respectively. Silenced EC remained capable to express characteristic endothelial surface markers such as CD31 and vascular endothelial cadherin important for constructing a tight barrier, as well as von Willebrand factor and endothelial nitric oxide synthase important for blood coagulation and vessel tone regulation. Moreover, HLA I-silenced EC were still able to align under unidirectional flow, to take up acetylated low-density lipoprotein, and to form capillary-like tube structures in three-dimensional fibrin gels similar to NT cells. In particular, addition of adipose tissue-derived mesenchymal stem cells significantly improved tube formation capability of HLA I-silenced EC toward long and widely branched vascular networks necessary for prevascularizing vascular grafts. Thus, silencing HLA I by RNAi represents a promising technique to reduce the immunogenic potential of EC from three different sources without interfering with EC-specific morphological and functional properties required for vascular tissue engineering. This extends the spectrum of available cell sources from autologous to allogeneic sources, thereby accelerating the generation of tissue-engineered vascular grafts in acute clinical cases.

Comparison of vessel enhancement algorithms applied to time-of-flight MRA images for cerebrovascular segmentation.

PubMed

Phellan, Renzo; Forkert, Nils D

2017-11-01

Vessel enhancement algorithms are often used as a preprocessing step for vessel segmentation in medical images to improve the overall segmentation accuracy. Each algorithm uses different characteristics to enhance vessels, such that the most suitable algorithm may vary for different applications. This paper presents a comparative analysis of the accuracy gains in vessel segmentation generated by the use of nine vessel enhancement algorithms: Multiscale vesselness using the formulas described by Erdt (MSE), Frangi (MSF), and Sato (MSS), optimally oriented flux (OOF), ranking orientations responses path operator (RORPO), the regularized Perona-Malik approach (RPM), vessel enhanced diffusion (VED), hybrid diffusion with continuous switch (HDCS), and the white top hat algorithm (WTH). The filters were evaluated and compared based on time-of-flight MRA datasets and corresponding manual segmentations from 5 healthy subjects and 10 patients with an arteriovenous malformation. Additionally, five synthetic angiographic datasets with corresponding ground truth segmentation were generated with three different noise levels (low, medium, and high) and also used for comparison. The parameters for each algorithm and subsequent segmentation were optimized using leave-one-out cross evaluation. The Dice coefficient, Matthews correlation coefficient, area under the ROC curve, number of connected components, and true positives were used for comparison. The results of this study suggest that vessel enhancement algorithms do not always lead to more accurate segmentation results compared to segmenting nonenhanced images directly. Multiscale vesselness algorithms, such as MSE, MSF, and MSS proved to be robust to noise, while diffusion-based filters, such as RPM, VED, and HDCS ranked in the top of the list in scenarios with medium or no noise. Filters that assume tubular-shapes, such as MSE, MSF, MSS, OOF, RORPO, and VED show a decrease in accuracy when considering patients with an AVM, because vessels may vary from its tubular-shape in this case. Vessel enhancement algorithms can help to improve the accuracy of the segmentation of the vascular system. However, their contribution to accuracy has to be evaluated as it depends on the specific applications, and in some cases it can lead to a reduction of the overall accuracy. No specific filter was suitable for all tested scenarios. © 2017 American Association of Physicists in Medicine.

Development of an oxygen saturation measuring system by using near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Kono, K.; Nakamachi, E.; Morita, Y.

2017-08-01

Recently, the hypoxia imaging has been recognized as the advanced technique to detect cancers because of a strong relationship with the biological characterization of cancer. In previous studies, hypoxia imaging systems for endoscopic diagnosis have been developed. However, these imaging technologies using the visible light can observe only blood vessels in gastric mucous membrane. Therefore, they could not detect scirrhous gastric cancer which accounts for 10% of all gastric cancers and spreads rapidly into submucous membrane. To overcome this problem, we developed a measuring system of blood oxygen saturation in submucous membrane by using near-infrared (NIR) spectroscopy. NIR, which has high permeability for bio-tissues and high absorbency for hemoglobin, can image and observe blood vessels in submucous membrane. NIR system with LED lights and a CCD camera module was developed to image blood vessels. We measured blood oxygen saturation using the optical density ratio (ODR) of two wavelengths, based on Lambert-Beer law. To image blood vessel clearly and measure blood oxygen saturation accurately, we searched two optimum wavelengths by using a multilayer human gastric-like phantom which has same optical properties as human gastric one. By using Monte Carlo simulation of light propagation, we derived the relationship between the ODR and blood oxygen saturation and elucidated the influence of blood vessel depth on measuring blood oxygen saturation. The oxygen saturation measuring methodology was validated with experiments using our NIR system. Finally, it was confirmed that our system can detect oxygen saturation in various depth blood vessels accurately.

Capacitance-level/density monitor for fluidized-bed combustor

DOEpatents

Fasching, George E.; Utt, Carroll E.

1982-01-01

A multiple segment three-terminal type capacitance probe with segment selection, capacitance detection and compensation circuitry and read-out control for level/density measurements in a fluidized-bed vessel is provided. The probe is driven at a high excitation frequency of up to 50 kHz to sense quadrature (capacitive) current related to probe/vessel capacitance while being relatively insensitive to the resistance current component. Compensation circuitry is provided for generating a negative current of equal magnitude to cancel out only the resistive component current. Clock-operated control circuitry separately selects the probe segments in a predetermined order for detecting and storing this capacitance measurement. The selected segment acts as a guarded electrode and is connected to the read-out circuitry while all unselected segments are connected to the probe body, which together form the probe guard electrode. The selected probe segment capacitance component signal is directed to a corresponding segment channel sample and hold circuit dedicated to that segment to store the signal derived from that segment. This provides parallel outputs for display, computer input, etc., for the detected capacitance values. The rate of segment sampling may be varied to either monitor the dynamic density profile of the bed (high sampling rate) or monitor average bed characteristics (slower sampling rate).

Chronic cocaine disrupts neurovascular networks and cerebral function: optical imaging studies in rodents

NASA Astrophysics Data System (ADS)

Zhang, Qiujia; You, Jiang; Volkow, Nora D.; Choi, Jeonghun; Yin, Wei; Wang, Wei; Pan, Yingtian; Du, Congwu

2016-02-01

Cocaine abuse can lead to cerebral strokes and hemorrhages secondary to cocaine's cerebrovascular effects, which are poorly understood. We assessed cocaine's effects on cerebrovascular anatomy and function in the somatosensory cortex of the rat's brain. Optical coherence tomography was used for in vivo imaging of three-dimensional cerebral blood flow (CBF) networks and to quantify CBF velocities (CBFv), and multiwavelength laser-speckle-imaging was used to simultaneously measure changes in CBFv, oxygenated (Δ[HbO2]) and deoxygenated hemoglobin (Δ[HbR]) concentrations prior to and after an acute cocaine challenge in chronically cocaine exposed rats. Immunofluorescence techniques on brain slices were used to quantify microvasculature density and levels of vascular endothelial growth factor (VEGF). After chronic cocaine (2 and 4 weeks), CBFv in small vessels decreased, whereas vasculature density and VEGF levels increased. Acute cocaine further reduced CBFv and decreased Δ[HbO2] and this decline was larger and longer lasting in 4 weeks than 2 weeks cocaine-exposed rats, which indicates that risk for ischemia is heightened during intoxication and that it increases with chronic exposures. These results provide evidence of cocaine-induced angiogenesis in cortex. The CBF reduction after chronic cocaine exposure, despite the increases in vessel density, indicate that angiogenesis was insufficient to compensate for cocaine-induced disruption of cerebrovascular function.

Edge properties with the liquid lithium limiter in FTU—experiment and transport modelling

NASA Astrophysics Data System (ADS)

Pericoli-Ridolfini, V.; Apicella, M. L.; Mazzitelli, G.; Tudisco, O.; Zagórski, R.; FTU Team

2007-07-01

Liquid lithium as a plasma-facing material was tested for the first time on a high field medium size tokamak, FTU. A liquid Li reservoir supplies a mesh of capillaries that is movable from shot to shot in the scrape-off layer (SOL) plasma to act as a secondary limiter. An almost complete lithization of the vacuum vessel walls is obtained in about three discharges. Plasmas cleaner than boronization and titanization, with lower radiation losses and smaller impurity content are produced. The SOL electron temperature increases, ΔTe ~ 10 eV, while density (ne) is less affected. The 2D multifluid code TECXY explains this only if a strong reduction of plasma recycling on the walls and main limiter occurs, consistent with the high Li hydrogen pumping capability. This property also permits a much tighter control of the plasma density. With the Li limiter inserted inside the vessel poloidal asymmetries develop in the SOL that TECXY explains with a local increase of radiation, caused by enhanced evaporation/sputtering of Li. New regimes can be produced in such conditions with a clear increase in |∇ne/ne| and of the peaking factor ne0/

In vitro growth of Curcuma longa L. in response to five mineral elements and plant density in fed-batch culture systems.

PubMed

El-Hawaz, Rabia F; Bridges, William C; Adelberg, Jeffrey W

2015-01-01

Plant density was varied with P, Ca, Mg, and KNO3 in a multifactor experiment to improve Curcuma longa L. micropropagation, biomass and microrhizome development in fed-batch liquid culture. The experiment had two paired D-optimal designs, testing sucrose fed-batch and nutrient sucrose fed-batch techniques. When sucrose became depleted, volume was restored to 5% m/v sucrose in 200 ml of modified liquid MS medium by adding sucrose solutions. Similarly, nutrient sucrose fed-batch was restored to set points with double concentration of treatments' macronutrient and MS micronutrient solutions, along with sucrose solutions. Changes in the amounts of water and sucrose supplementations were driven by the interaction of P and KNO3 concentrations. Increasing P from 1.25 to 6.25 mM increased both multiplication and biomass. The multiplication ratio was greatest in the nutrient sucrose fed-batch technique with the highest level of P, 6 buds/vessel, and the lowest level of Ca and KNO3. The highest density (18 buds/vessel) produced the highest fresh biomass at the highest concentrations of KNO3 and P with nutrient sucrose fed-batch, and moderate Ca and Mg concentrations. However, maximal rhizome dry biomass required highest P, sucrose fed-batch, and a moderate plant density. Different media formulations and fed-batch techniques were identified to maximize the propagation and storage organ responses. A single experimental design was used to optimize these dual purposes.

In Vitro Growth of Curcuma longa L. in Response to Five Mineral Elements and Plant Density in Fed-Batch Culture Systems

PubMed Central

El-Hawaz, Rabia F.; Bridges, William C.; Adelberg, Jeffrey W.

2015-01-01

Plant density was varied with P, Ca, Mg, and KNO3 in a multifactor experiment to improve Curcuma longa L. micropropagation, biomass and microrhizome development in fed-batch liquid culture. The experiment had two paired D-optimal designs, testing sucrose fed-batch and nutrient sucrose fed-batch techniques. When sucrose became depleted, volume was restored to 5% m/v sucrose in 200 ml of modified liquid MS medium by adding sucrose solutions. Similarly, nutrient sucrose fed-batch was restored to set points with double concentration of treatments’ macronutrient and MS micronutrient solutions, along with sucrose solutions. Changes in the amounts of water and sucrose supplementations were driven by the interaction of P and KNO3 concentrations. Increasing P from 1.25 to 6.25 mM increased both multiplication and biomass. The multiplication ratio was greatest in the nutrient sucrose fed-batch technique with the highest level of P, 6 buds/vessel, and the lowest level of Ca and KNO3. The highest density (18 buds/vessel) produced the highest fresh biomass at the highest concentrations of KNO3 and P with nutrient sucrose fed-batch, and moderate Ca and Mg concentrations. However, maximal rhizome dry biomass required highest P, sucrose fed-batch, and a moderate plant density. Different media formulations and fed-batch techniques were identified to maximize the propagation and storage organ responses. A single experimental design was used to optimize these dual purposes. PMID:25830292

Functional relationships between wood structure and vulnerability to xylem cavitation in races of Eucalyptus globulus differing in wood density.

PubMed

Barotto, Antonio José; Monteoliva, Silvia; Gyenge, Javier; Martinez-Meier, Alejandro; Fernandez, María Elena

2018-02-01

Wood density can be considered as a measure of the internal wood structure, and it is usually used as a proxy measure of other mechanical and functional traits. Eucalyptus is one of the most important commercial forestry genera worldwide, but the relationship between wood density and vulnerability to cavitation in this genus has been little studied. The analysis is hampered by, among other things, its anatomical complexity, so it becomes necessary to address more complex techniques and analyses to elucidate the way in which the different anatomical elements are functionally integrated. In this study, vulnerability to cavitation in two races of Eucalyptus globulus Labill. with different wood density was evaluated through Path analysis, a multivariate method that allows evaluation of descriptive models of causal relationship between variables. A model relating anatomical variables with wood properties and functional parameters was proposed and tested. We found significant differences in wood basic density and vulnerability to cavitation between races. The main exogenous variables predicting vulnerability to cavitation were vessel hydraulic diameter and fibre wall fraction. Fibre wall fraction showed a direct impact on wood basic density and the slope of vulnerability curve, and an indirect and negative effect over the pressure imposing 50% of conductivity loss (P50) through them. Hydraulic diameter showed a direct negative effect on P50, but an indirect and positive influence over this variable through wood density on one hand, and through maximum hydraulic conductivity (ks max) and slope on the other. Our results highlight the complexity of the relationship between xylem efficiency and safety in species with solitary vessels such as Eucalyptus spp., with no evident compromise at the intraspecific level. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A comparison of two methods for measuring vessel length in woody plants.

PubMed

Pan, Ruihua; Geng, Jing; Cai, Jing; Tyree, Melvin T

2015-12-01

Vessel lengths are important to plant hydraulic studies, but are not often reported because of the time required to obtain measurements. This paper compares the fast dynamic method (air injection method) with the slower but traditional static method (rubber injection method). Our hypothesis was that the dynamic method should yield a larger mean vessel length than the static method. Vessel length was measured by both methods in current year stems of Acer, Populus, Vitis and Quercus representing short- to long-vessel species. The hypothesis was verified. The reason for the consistently larger values of vessel length is because the dynamic method measures air flow rates in cut open vessels. The Hagen-Poiseuille law predicts that the air flow rate should depend on the product of number of cut open vessels times the fourth power of vessel diameter. An argument is advanced that the dynamic method is more appropriate because it measures the length of the vessels that contribute most to hydraulic flow. If all vessels had the same vessel length distribution regardless of diameter, then both methods should yield the same average length. This supports the hypothesis that large-diameter vessels might be longer than short-diameter vessels in most species. © 2015 John Wiley & Sons Ltd.

Myocytes of chorionic vessels from placentas with meconium-associated vascular necrosis exhibit apoptotic markers.

PubMed

King, Erin L; Redline, Raymond W; Smith, Steven D; Kraus, Frederick T; Sadovsky, Yoel; Nelson, D Michael

2004-04-01

Meconium-associated vascular necrosis (MAVN) is a histological abnormality of human placental chorionic vessels that is associated with poor neonatal outcome. We tested the hypothesis that MAVN shows apoptosis in the walls of chorionic vessels. Archival placental specimens with MAVN (n = 5) were compared with specimens from uncomplicated pregnancies at term (n = 5) and from placentas with intense chorionic vasculitis associated with acute chorioamnionitis with (n = 5) or without (n = 5) a clinical history of meconium in the amniotic fluid. Sections from all placentas were processed by the TUNEL method, and 2 observers who were blinded to specimen diagnosis quantified the immunofluorescent TUNEL staining in both the amnion-facing and villous-facing walls of the larger chorionic vessels in each specimen. Compared with the other 3 groups, only the amnion-facing wall of chorionic vessels in MAVN showed a significantly greater number of apoptotic cells. This was verified by morphological criteria and caspase 3 staining. There were limited or no detectable TUNEL-stained cells in either the villous-facing walls of vessels in the MAVN specimens or in any of the vessels of the placentas from uncomplicated pregnancies. There was a negligible level of apoptosis in chorionic vessels of placentas with intense chorionic vasculitis, with or without meconium, despite the inflammatory response or presence of meconium. We conclude that apoptosis contributes to the pathophysiology of MAVN.

Histological evaluation and optimization of surgical vessel sealing systems

NASA Astrophysics Data System (ADS)

Lathrop, Robert; Ryan, Thomas; Gaspredes, Jonathan; Woloszko, Jean; Coad, James E.

2017-02-01

Surgical vessel sealing systems are widely used to achieve hemostasis and dissection in open surgery and minimally invasive, laparoscopic surgery. This enabling technology was developed about 17 years ago and continues to evolve with new devices and systems achieving improved outcomes. Histopathological assessment of thermally sealed tissues is a valuable tool for refining and comparing performance among surgical vessel sealing systems. Early work in this field typically assessed seal time, burst rate, and failure rate (in-situ). Later work compared histological staining methods with birefringence to assess the extent of thermal damage to tissues adjacent to the device. Understanding the microscopic architecture of a sealed vessel is crucial to optimizing the performance of power delivery algorithms and device design parameters. Manufacturers rely on these techniques to develop new products. A system for histopathological evaluation of vessels and sealing performance was established, to enable the direct assessment of a treatment's tissue effects. The parameters included the commonly used seal time, pressure burst rate and failure rate, as well as extensions of the assessment to include its likelihood to form steam vacuoles, adjacent thermal effect near the device, and extent of thermally affected tissue extruded back into the vessel lumen. This comprehensive assessment method provides an improved means of assessing the quality of a sealed vessel and understanding the exact mechanisms which create an optimally sealed vessel.

Vessel segmentation in 3D spectral OCT scans of the retina

NASA Astrophysics Data System (ADS)

Niemeijer, Meindert; Garvin, Mona K.; van Ginneken, Bram; Sonka, Milan; Abràmoff, Michael D.

2008-03-01

The latest generation of spectral optical coherence tomography (OCT) scanners is able to image 3D cross-sectional volumes of the retina at a high resolution and high speed. These scans offer a detailed view of the structure of the retina. Automated segmentation of the vessels in these volumes may lead to more objective diagnosis of retinal vascular disease including hypertensive retinopathy, retinopathy of prematurity. Additionally, vessel segmentation can allow color fundus images to be registered to these 3D volumes, possibly leading to a better understanding of the structure and localization of retinal structures and lesions. In this paper we present a method for automatically segmenting the vessels in a 3D OCT volume. First, the retina is automatically segmented into multiple layers, using simultaneous segmentation of their boundary surfaces in 3D. Next, a 2D projection of the vessels is produced by only using information from certain segmented layers. Finally, a supervised, pixel classification based vessel segmentation approach is applied to the projection image. We compared the influence of two methods for the projection on the performance of the vessel segmentation on 10 optic nerve head centered 3D OCT scans. The method was trained on 5 independent scans. Using ROC analysis, our proposed vessel segmentation system obtains an area under the curve of 0.970 when compared with the segmentation of a human observer.

Automated tracking and quantification of angiogenic vessel formation in 3D microfluidic devices.

PubMed

Wang, Mengmeng; Ong, Lee-Ling Sharon; Dauwels, Justin; Asada, H Harry

2017-01-01

Angiogenesis, the growth of new blood vessels from pre-existing vessels, is a critical step in cancer invasion. Better understanding of the angiogenic mechanisms is required to develop effective antiangiogenic therapies for cancer treatment. We culture angiogenic vessels in 3D microfluidic devices under different Sphingosin-1-phosphate (S1P) conditions and develop an automated vessel formation tracking system (AVFTS) to track the angiogenic vessel formation and extract quantitative vessel information from the experimental time-lapse phase contrast images. The proposed AVFTS first preprocesses the experimental images, then applies a distance transform and an augmented fast marching method in skeletonization, and finally implements the Hungarian method in branch tracking. When applying the AVFTS to our experimental data, we achieve 97.3% precision and 93.9% recall by comparing with the ground truth obtained from manual tracking by visual inspection. This system enables biologists to quantitatively compare the influence of different growth factors. Specifically, we conclude that the positive S1P gradient increases cell migration and vessel elongation, leading to a higher probability for branching to occur. The AVFTS is also applicable to distinguish tip and stalk cells by considering the relative cell locations in a branch. Moreover, we generate a novel type of cell lineage plot, which not only provides cell migration and proliferation histories but also demonstrates cell phenotypic changes and branch information.

Electrolysis-needle cauterization of corneal vessels in patients with lipid keratopathy.

PubMed

Wertheim, Michael S; Cook, Stuart D; Knox-Cartwright, Nathaniel E; Van, Dung Le; Tole, Derek M

2007-02-01

To describe a technique of corneal vessel occlusion by using electrolysis-needle cautery. A prospective case series of three patients. Corneal vessels were successfully occluded in all patients. Vessels remained occluded during the first 8 months post-cautery follow up. Two patients needed repeat cautery at 9 and 10 months respectively. Patients found the procedure comfortable. There was no post-operative induced astigmatism. The technique of ENC is simple, effective and controlled. This technique compares favorably and may prove to be more versatile than Fine Needle Diathermy in the occlusion of corneal vessels that lead to lipid keratopathy.

46 CFR 131.960 - Use of auto-pilot.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Use of auto-pilot. 131.960 Section 131.960 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Miscellaneous § 131.960 Use of auto-pilot. When the automatic pilot is used in areas of high traffic density...

46 CFR 131.960 - Use of auto-pilot.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Use of auto-pilot. 131.960 Section 131.960 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Miscellaneous § 131.960 Use of auto-pilot. When the automatic pilot is used in areas of high traffic density...

46 CFR 131.960 - Use of auto-pilot.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Use of auto-pilot. 131.960 Section 131.960 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Miscellaneous § 131.960 Use of auto-pilot. When the automatic pilot is used in areas of high traffic density...

46 CFR 131.960 - Use of auto-pilot.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Use of auto-pilot. 131.960 Section 131.960 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Miscellaneous § 131.960 Use of auto-pilot. When the automatic pilot is used in areas of high traffic density...

46 CFR 131.960 - Use of auto-pilot.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Use of auto-pilot. 131.960 Section 131.960 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Miscellaneous § 131.960 Use of auto-pilot. When the automatic pilot is used in areas of high traffic density...

61 FR 41385 - Notice of Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

1996-08-08

... PRESSURE VESSEL; filed 24 February 1995; patented 21 November 1995.// Patent 5,468,356: LARGE SCALE...,477,482: ULTRA HIGH DENSITY, NON- VOLATILE FERROMAGNETIC RANDOM ACCESS MEMORY; filed 1 October 1993....// Patent 5,483,017: HIGH TEMPERATURE THERMOSETS AND CERAMICS DERIVED FROM LINEAR CARBORANE-(SILOXANE OR...

Weak-beam scanning transmission electron microscopy for quantitative dislocation density measurement in steels.

PubMed

Yoshida, Kenta; Shimodaira, Masaki; Toyama, Takeshi; Shimizu, Yasuo; Inoue, Koji; Yoshiie, Toshimasa; Milan, Konstantinovic J; Gerard, Robert; Nagai, Yasuyoshi

2017-04-01

To evaluate dislocations induced by neutron irradiation, we developed a weak-beam scanning transmission electron microscopy (WB-STEM) system by installing a novel beam selector, an annular detector, a high-speed CCD camera and an imaging filter in the camera chamber of a spherical aberration-corrected transmission electron microscope. The capabilities of the WB-STEM with respect to wide-view imaging, real-time diffraction monitoring and multi-contrast imaging are demonstrated using typical reactor pressure vessel steel that had been used in an European nuclear reactor for 30 years as a surveillance test piece with a fluence of 1.09 × 1020 neutrons cm-2. The quantitatively measured size distribution (average loop size = 3.6 ± 2.1 nm), number density of the dislocation loops (3.6 × 1022 m-3) and dislocation density (7.8 × 1013 m m-3) were carefully compared with the values obtained via conventional weak-beam transmission electron microscopy studies. In addition, cluster analysis using atom probe tomography (APT) further demonstrated the potential of the WB-STEM for correlative electron tomography/APT experiments. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Quantification of Pulmonary Fibrosis in a Bleomycin Mouse Model Using Automated Histological Image Analysis.

PubMed

Gilhodes, Jean-Claude; Julé, Yvon; Kreuz, Sebastian; Stierstorfer, Birgit; Stiller, Detlef; Wollin, Lutz

2017-01-01

Current literature on pulmonary fibrosis induced in animal models highlights the need of an accurate, reliable and reproducible histological quantitative analysis. One of the major limits of histological scoring concerns the fact that it is observer-dependent and consequently subject to variability, which may preclude comparative studies between different laboratories. To achieve a reliable and observer-independent quantification of lung fibrosis we developed an automated software histological image analysis performed from digital image of entire lung sections. This automated analysis was compared to standard evaluation methods with regard to its validation as an end-point measure of fibrosis. Lung fibrosis was induced in mice by intratracheal administration of bleomycin (BLM) at 0.25, 0.5, 0.75 and 1 mg/kg. A detailed characterization of BLM-induced fibrosis was performed 14 days after BLM administration using lung function testing, micro-computed tomography and Ashcroft scoring analysis. Quantification of fibrosis by automated analysis was assessed based on pulmonary tissue density measured from thousands of micro-tiles processed from digital images of entire lung sections. Prior to analysis, large bronchi and vessels were manually excluded from the original images. Measurement of fibrosis has been expressed by two indexes: the mean pulmonary tissue density and the high pulmonary tissue density frequency. We showed that tissue density indexes gave access to a very accurate and reliable quantification of morphological changes induced by BLM even for the lowest concentration used (0.25 mg/kg). A reconstructed 2D-image of the entire lung section at high resolution (3.6 μm/pixel) has been performed from tissue density values allowing the visualization of their distribution throughout fibrotic and non-fibrotic regions. A significant correlation (p<0.0001) was found between automated analysis and the above standard evaluation methods. This correlation establishes automated analysis as a novel end-point measure of BLM-induced lung fibrosis in mice, which will be very valuable for future preclinical drug explorations.

Quantification of Pulmonary Fibrosis in a Bleomycin Mouse Model Using Automated Histological Image Analysis

PubMed Central

Gilhodes, Jean-Claude; Kreuz, Sebastian; Stierstorfer, Birgit; Stiller, Detlef; Wollin, Lutz

2017-01-01

Current literature on pulmonary fibrosis induced in animal models highlights the need of an accurate, reliable and reproducible histological quantitative analysis. One of the major limits of histological scoring concerns the fact that it is observer-dependent and consequently subject to variability, which may preclude comparative studies between different laboratories. To achieve a reliable and observer-independent quantification of lung fibrosis we developed an automated software histological image analysis performed from digital image of entire lung sections. This automated analysis was compared to standard evaluation methods with regard to its validation as an end-point measure of fibrosis. Lung fibrosis was induced in mice by intratracheal administration of bleomycin (BLM) at 0.25, 0.5, 0.75 and 1 mg/kg. A detailed characterization of BLM-induced fibrosis was performed 14 days after BLM administration using lung function testing, micro-computed tomography and Ashcroft scoring analysis. Quantification of fibrosis by automated analysis was assessed based on pulmonary tissue density measured from thousands of micro-tiles processed from digital images of entire lung sections. Prior to analysis, large bronchi and vessels were manually excluded from the original images. Measurement of fibrosis has been expressed by two indexes: the mean pulmonary tissue density and the high pulmonary tissue density frequency. We showed that tissue density indexes gave access to a very accurate and reliable quantification of morphological changes induced by BLM even for the lowest concentration used (0.25 mg/kg). A reconstructed 2D-image of the entire lung section at high resolution (3.6 μm/pixel) has been performed from tissue density values allowing the visualization of their distribution throughout fibrotic and non-fibrotic regions. A significant correlation (p<0.0001) was found between automated analysis and the above standard evaluation methods. This correlation establishes automated analysis as a novel end-point measure of BLM-induced lung fibrosis in mice, which will be very valuable for future preclinical drug explorations. PMID:28107543

A comparative study of Cyclofem and depot medroxyprogesterone acetate (DMPA) effects on endometrial vasculature.

PubMed

Simbar, Masoumeh; Tehrani, Fahimeh Ramezani; Hashemi, Zeinab; Zham, Hananeh; Fraser, Ian S

2007-10-01

The most common reason for discontinuation of long-acting progestogen-only contraceptives is irregular bleeding following local endometrial vascular changes. To reduce unpredictable bleeding episodes among depot medroxyprogesterone acetate (DMPA) users, the combined injectable contraceptive, Cyclofem, was offered as an alternative. However, there is a gap in our knowledge about the effects of Cyclofem on the endometrial vasculature and patterns of bleeding. This study aimed to compare the effects of Cyclofem and DMPA on endometrial vascular density, endometrial histology and pattern of bleeding. Sixty-eight healthy women with regular menstrual bleeding and seeking injectable long-acting contraceptives were recruited. Two endometrial samples (before and 3 to 6 months after initial exposure to DMPA or Cyclofem) were collected from each participant. The samples were stained using an immunohistochemical method and anti-CD34 to visualise the endometrial vasculature. Endometrial vascular density was assessed using standard techniques. Sixty-eight women were randomly assigned to Cyclofem (38 women) or DMPA (30 women). Endometrial vascular density was 149.3 +/- 6.7 (mean +/- SD)/mm(2) before injection. This significantly decreased to 132.4 +/- 12.2 after DMPA use, and from 151.9 +/- 5.8 to 131.8 +/- 12.8 vessels/mm(2) following Cyclofem use (paired t-test, p <0.05). However, there was no significant difference between endometrial vascular density during treatment with Cyclofem or DMPA. Total bleeding days in the first and second 3-month time intervals were 28 +/- 23 and 18 +/- 12 days in DMPA users and 22 +/- 14 and 16 +/- 9 days in Cyclofem users, respectively, Spotting was the most common type of bleeding experienced, and atrophic endometrium was the most common histological pattern observed in both groups. This study demonstrated that both Cyclofem and DMPA use are associated with decreased endometrial vascular density and atrophic endometrium, in addition to irregular bleeding, mainly spotting. There was no significant difference in bleeding patterns or endometrial findings observed for these two injectable contraceptives in Iranian women.

Physical modelling of LNG rollover in a depressurized container filled with water

NASA Astrophysics Data System (ADS)

Maksim, Dadonau; Denissenko, Petr; Hubert, Antoine; Dembele, Siaka; Wen, Jennifer

2015-11-01

Stable density stratification of multi-component Liquefied Natural Gas causes it to form distinct layers, with upper layer having a higher fraction of the lighter components. Heat flux through the walls and base of the container results in buoyancy-driven convection accompanied by heat and mass transfer between the layers. The equilibration of densities of the top and bottom layers, normally caused by the preferential evaporation of Nitrogen, may induce an imbalance in the system and trigger a rapid mixing process, so-called rollover. Numerical simulation of the rollover is complicated and codes require validation. Physical modelling of the phenomenon has been performed in a water-filled depressurized vessel. Reducing gas pressure in the container to levels comparable to the hydrostatic pressure in the water column allows modelling of tens of meters industrial reservoirs using a 20 cm laboratory setup. Additionally, it allows to model superheating of the base fluid layer at temperatures close the room temperature. Flow visualizations and parametric studies are presented. Results are related to outcomes of numerical modelling.

Simulations of dissociation constants in low pressure supercritical water

NASA Astrophysics Data System (ADS)

Halstead, S. J.; An, P.; Zhang, S.

2014-09-01

This article reports molecular dynamics simulations of the dissociation of hydrochloric acid and sodium hydroxide in water from ambient to supercritical temperatures at a fixed pressure of 250 atm. Corrosion of reaction vessels is known to be a serious problem of supercritical water, and acid/base dissociation can be a significant contributing factor to this. The SPC/e model was used in conjunction with solute models determined from density functional calculations and OPLSAA Lennard-Jones parameters. Radial distribution functions were calculated, and these show a significant increase in solute-solvent ordering upon forming the product ions at all temperatures. For both dissociations, rapidly decreasing entropy of reaction was found to be the controlling thermodynamic factor, and this is thought to arise due to the ions produced from dissociation maintaining a relatively high density and ordered solvation shell compared to the reactants. The change in entropy of reaction reaches a minimum at the critical temperature. The values of pKa and pKb were calculated and both increased with temperature, in qualitative agreement with other work, until a maximum value at 748 K, after which there was a slight decrease.

Impact of carotid stent cell design on vessel scaffolding: a case study comparing experimental investigation and numerical simulations.

PubMed

Conti, Michele; Van Loo, Denis; Auricchio, Ferdinando; De Beule, Matthieu; De Santis, Gianluca; Verhegghe, Benedict; Pirrelli, Stefano; Odero, Attilio

2011-06-01

To quantitatively evaluate the impact of carotid stent cell design on vessel scaffolding by using patient-specific finite element analysis of carotid artery stenting (CAS). The study was organized in 2 parts: (1) validation of a patient-specific finite element analysis of CAS and (2) evaluation of vessel scaffolding. Micro-computed tomography (CT) images of an open-cell stent deployed in a patient-specific silicone mock artery were compared with the corresponding finite element analysis results. This simulation was repeated for the closed-cell counterpart. In the second part, the stent strut distribution, as reflected by the inter-strut angles, was evaluated for both cell types in different vessel cross sections as a measure of scaffolding. The results of the patient-specific finite element analysis of CAS matched well with experimental stent deployment both qualitatively and quantitatively, demonstrating the reliability of the numerical approach. The measured inter-strut angles suggested that the closed-cell design provided superior vessel scaffolding compared to the open-cell counterpart. However, the full strut interconnection of the closed-cell design reduced the stent's ability to accommodate to the irregular eccentric profile of the vessel cross section, leading to a gap between the stent surface and the vessel wall. Even though this study was limited to a single stent design and one vascular anatomy, the study confirmed the capability of dedicated computer simulations to predict differences in scaffolding by open- and closed-cell carotid artery stents. These simulations have the potential to be used in the design of novel carotid stents or for procedure planning.

Validation and Verification of Composite Pressure Vessel Design

NASA Technical Reports Server (NTRS)

Kreger, Stephen T.; Ortyl, Nicholas; Grant, Joseph; Taylor, F. Tad

2006-01-01

Ten composite pressure vessels were instrumented with fiber Bragg grating sensors and pressure tested Through burst. This paper and presentation will discuss the testing methodology, the test results, compare the testing results to the analytical model, and also compare the fiber Bragg grating sensor data with data obtained against that obtained from foil strain gages.

Distribution of Different Sized Ocular Surface Vessels in Diabetics and Normal Individuals.

PubMed

Banaee, Touka; Pourreza, Hamidreza; Doosti, Hassan; Abrishami, Mojtaba; Ehsaei, Asieh; Basiry, Mohsen; Pourreza, Reza

2017-01-01

To compare the distribution of different sized vessels using digital photographs of the ocular surface of diabetic and normal individuals. In this cross-sectional study, red-free conjunctival photographs of diabetic and normal individuals, aged 30-60 years, were taken under defined conditions and analyzed using a Radon transform-based algorithm for vascular segmentation. The image areas occupied by vessels (AOV) of different diameters were calculated. The main outcome measure was the distribution curve of mean AOV of different sized vessels. Secondary outcome measures included total AOV and standard deviation (SD) of AOV of different sized vessels. Two hundred and sixty-eight diabetic patients and 297 normal (control) individuals were included, differing in age (45.50 ± 5.19 vs. 40.38 ± 6.19 years, P < 0.001), systolic (126.37 ± 20.25 vs. 119.21 ± 15.81 mmHg, P < 0.001) and diastolic (78.14 ± 14.21 vs. 67.54 ± 11.46 mmHg, P < 0.001) blood pressures. The distribution curves of mean AOV differed between patients and controls (smaller AOV for larger vessels in patients; P < 0.001) as well as between patients without retinopathy and those with non-proliferative diabetic retinopathy (NPDR); with larger AOV for smaller vessels in NPDR ( P < 0.001). Controlling for the effect of confounders, patients had a smaller total AOV, larger total SD of AOV, and a more skewed distribution curve of vessels compared to controls. Presence of diabetes mellitus is associated with contraction of larger vessels in the conjunctiva. Smaller vessels dilate with diabetic retinopathy. These findings may be useful in the photographic screening of diabetes mellitus and retinopathy.

Vasculature surrounding a nodule: A novel lung cancer biomarker.

PubMed

Wang, Xiaohua; Leader, Joseph K; Wang, Renwei; Wilson, David; Herman, James; Yuan, Jian-Min; Pu, Jiantao

2017-12-01

To investigate whether the vessels surrounding a nodule depicted on non-contrast, low-dose computed tomography (LDCT) can discriminate benign and malignant screen detected nodules. We collected a dataset consisting of LDCT scans acquired on 100 subjects from the Pittsburgh Lung Screening study (PLuSS). Fifty subjects were diagnosed with lung cancer and 50 subjects had suspicious nodules later proven benign. For the lung cancer cases, the location of the malignant nodule in the LDCT scans was known; while for the benign cases, the largest nodule in the LDCT scan was used in the analysis. A computer algorithm was developed to identify surrounding vessels and quantify the number and volume of vessels that were connected or near the nodule. A nonparametric receiver operating characteristic (ROC) analysis was performed based on a single nodule per subject to assess the discriminability of the surrounding vessels to provide a lung cancer diagnosis. Odds ratio (OR) were computed to determine the probability of a nodule being lung cancer based on the vessel features. The areas under the ROC curves (AUCs) for vessel count and vessel volume were 0.722 (95% CI=0.616-0.811, p<0.01) and 0.676 (95% CI=0.565-0.772), respectively. The number of vessels attached to a nodule was significantly higher in the lung cancer group 9.7 (±9.6) compared to the non-lung cancer group 4.0 (±4.3) CONCLUSION: Our preliminary results showed that malignant nodules are often surrounded by more vessels compared to benign nodules, suggesting that the surrounding vessel characteristics could serve as lung cancer biomarker for indeterminate nodules detected during LDCT lung cancer screening using only the information collected during the initial visit. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterising the grey matter correlates of leukoaraiosis in cerebral small vessel disease.

PubMed

Lambert, Christian; Sam Narean, Janakan; Benjamin, Philip; Zeestraten, Eva; Barrick, Thomas R; Markus, Hugh S

2015-01-01

Cerebral small vessel disease (SVD) is a heterogeneous group of pathological disorders that affect the small vessels of the brain and are an important cause of cognitive impairment. The ischaemic consequences of this disease can be detected using MRI, and include white matter hyperintensities (WMH), lacunar infarcts and microhaemorrhages. The relationship between SVD disease severity, as defined by WMH volume, in sporadic age-related SVD and cortical thickness has not been well defined. However, regional cortical thickness change would be expected due to associated phenomena such as underlying ischaemic white matter damage, and the observation that widespread cortical thinning is observed in the related genetic condition CADASIL (Righart et al., 2013). Using MRI data, we have developed a semi-automated processing pipeline for the anatomical analysis of individuals with cerebral small vessel disease and applied it cross-sectionally to 121 subjects diagnosed with this condition. Using a novel combined automated white matter lesion segmentation algorithm and lesion repair step, highly accurate warping to a group average template was achieved. The volume of white matter affected by WMH was calculated, and used as a covariate of interest in a voxel-based morphometry and voxel-based cortical thickness analysis. Additionally, Gaussian Process Regression (GPR) was used to assess if the severity of SVD, measured by WMH volume, could be predicted from the morphometry and cortical thickness measures. We found significant (Family Wise Error corrected p < 0.05) volumetric decline with increasing lesion load predominately in the parietal lobes, anterior insula and caudate nuclei bilaterally. Widespread significant cortical thinning was found bilaterally in the dorsolateral prefrontal, parietal and posterio-superior temporal cortices. These represent distinctive patterns of cortical thinning and volumetric reduction compared to ageing effects in the same cohort, which exhibited greater changes in the occipital and sensorimotor cortices. Using GPR, the absolute WMH volume could be significantly estimated from the grey matter density and cortical thickness maps (Pearson's coefficients 0.80 and 0.75 respectively). We demonstrate that SVD severity is associated with regional cortical thinning. Furthermore a quantitative measure of SVD severity (WMH volume) can be predicted from grey matter measures, supporting an association between white and grey matter damage. The pattern of cortical thinning and volumetric decline is distinctive for SVD severity compared to ageing. These results, taken together, suggest that there is a phenotypic pattern of atrophy associated with SVD severity.

Periodontal disease, tooth loss and coronary heart disease assessed by coronary angiography: a cross-sectional observational study.

PubMed

Zanella, S M; Pereira, S S; Barbisan, J N; Vieira, L; Saba-Chujfi, E; Haas, A N; Rösing, C K

2016-04-01

To evaluate the association between periodontal disease, tooth loss and coronary heart disease (CHD). There is still controversy about the relationship between periodontal disease and tooth loss with vessel obstruction assessed using coronary angiography. This cross-sectional study included 195 patients that underwent coronary angiography and presented with at least six teeth. Patients were classified into three categories of coronary obstruction severity: absence; one or more vessels with ≤ 50% obstruction; and one or more vessels with ≥ 50% obstruction. The extent of coronary obstruction was dichotomized into 0 and ≥ 1 affected vessels. A periodontist blinded to patient CHD status conducted a full mouth examination to determine mean clinical attachment loss, mean periodontal probing depth and tooth loss. Multiple logistic regression models were applied adjusting for age, gender, hypertension, smoking, body mass index, low-density lipoprotein cholesterol and C-reactive protein. Most patients were males (62.1%) older than 60 years (50.8%), and 61% of them had CHD. Mean periodontal probing depth, clinical attachment loss and tooth loss were 2.64 ± 0.72 mm, 4.40 ± 1.31 mm and 12.50 ± 6.98 teeth respectively. In the multivariable models, tooth loss was significantly associated with a higher chance of having at least one obstructed vessel (odds ratio = 1.04; 95% confidence interval 1.01-1.09) and with vessel obstruction ≥ 50% (odds ratio = 1.06; 95% confidence interval 1.01-1.11). No significant associations were found between periodontal variables and vessel obstruction. Tooth loss was found to be a risk indicator for CHD. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A new imaging technique for retinal vessel oximetry: principles and first clinical results in patients with retinal arterial occlusion and diabetic retinopathy

NASA Astrophysics Data System (ADS)

Hammer, M.; Riemer, T.; Vilser, W.; Gehlert, S.; Schweitzer, D.

2009-02-01

The oxygen saturation of blood inside retinal vessels is an essential measure for the estimation of oxygen supply to the tissue as well as its oxygen consumption. In the current approach, the blood oxygenation is measured by a dual-wavelength technique. Using a fundus camera, equipped with a special dual wavelength transmission filter and a color CCD camera, two monochromatic fundus images at 548 nm and 610 nm were recorded simultaneously. The optical densities of retinal vessels for both wavelengths and their ratio, which is known to be proportional to the oxygen saturation, were calculated. From a health control population, mean arterial and venous oxygen saturations were measured of 98+/-10.1% and 65+/-11.7% with reproducibility of 2.52% and 3.25% respectively. In 10 patients with arterial occlusion, a reduction of the arterial oxygen saturation to 78 +/-17% (mean +/- standard deviation, branch arterial occlusion) and 91+/-11% (central arterial occlusion) respectively was found in the occluded vessel. After 5 days on pentoxifilin therapy, the arterial saturation increased to an average of 93+/-12% or 103 +/-6% respectively. In 70 eyes of 42 patients suffering from diabetic retinopathy, an increase of the venous oxygen saturation with the severity of the retinopathy was found (mild nonproliferative retinopathy: 68.4+/-8.2%, moderate non-proliferative retinopathy: 70.5+/-6.8%, severe non-proliferative retinopathy: 72.4+/-7.6%, proliferative retinopathy 75.7+/-8.3%) due to vessel shunting and diabetic changes of the permeability of vessel walls. These first clinical results demonstrate the ability of an accurate measurement of retinal vessel oxygenation with a very simple setup just requiring a special filter in the illumination path of a fundus camera and dedicated software.

Gradient changes in porcine renal arterial vascular anatomy and blood flow after cryoablation.

PubMed

Lagerveld, Brunolf W; van Horssen, Pepijn; Laguna, M Pilar; van den Wijngaard, Jeroen P H M; Siebes, Maria; Wijkstra, Hessel; de la Rosette, Jean J M C H; Spaan, Jos A E

2011-08-01

We quantified temporal changes in vascular structure and blood flow after cryosurgery of the porcine kidney in vivo. We studied 5 groups of 4 kidneys each with a survival time of 20 minutes, 4 hours, 2 days, and 1 and 2 weeks after cryoablation, respectively. Before harvesting the kidneys, fluorescently labeled microspheres were administrated in the descending aorta. After harvest the kidney and its vasculature were casted with fluorescently dyed elastomer, frozen and processed in an imaging cryomicrotome to reveal the 3-dimensional arterial branching structure and microsphere distribution. In regions of interest vessels were segmented by image analysis software and histograms were constructed to reveal the total summed vessel length as a function of diameter. A characteristic diameter of the ablated area was measured. The 20-minute survival group histograms showed a significant shift of the peak to larger diameters (p<0.002), indicating that smaller vessels were destroyed. Microsphere density was decreased to 2% in the ablated region but not in the nonablated border zone, depending on the remaining crater crossing larger vessels. After 2 weeks neither vessels nor microspheres were left in the ablated area, which had shrunk by about 40% in diameter. Study limitations are the lack of histological confirmation and the use of normal rather than cancerous tissue. Larger vessels remain patent just after ablation and transport blood to the border of the ablation crater but perfusion within the crater is halted instantly. Characteristic crater diameter increases initially but decreases thereafter. Destruction of vessels and tissue is complete 2 weeks after cryoablation. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Bone vascularization and bone micro-architecture characterizations according to the μCT resolution

NASA Astrophysics Data System (ADS)

Crauste, E.; Autrusseau, F.; Guédon, Jp.; Pilet, P.; Amouriq, Y.; Weiss, P.; Giumelli, B.

2015-03-01

Trabecular bone and its micro-architecture are of prime importance for health. Changes of bone micro-architecture are linked to different pathological situations like osteoporosis and begin now to be understood. In a previous paper [12], we started to investigate the relationships between bone and vessels and proposed some indices of characterization for the vessels issued from those used for the bone. Our main objective in this paper is to qualify the classical values used for bone as well as those we proposed for vessels according to different acquisition parameters and for several thresholding methods used to separate bone vessels and background. This study is also based on vessels perfusion by a contrast agent (barium sulfate mixed with gelatin) before euthanasia on rats. Femurs and tibias as well as mandibles were removed after rat's death and were imaged by microCT (Skyscan 1272, Bruker, Belgium) with a resolution ranging from 18 to 3μm. The so obtained images were analyzed with various softwares (NRecon Reconstruction, CtAn, and CtVox from Bruker) in order to calculate bone and vessels micro-architecture parameters (density of bone/blood within the volume), and to know if the results both for bone and vascular micro-architecture are constant along the chosen pixel resolution. The result is clearly negative. We found a very different characterization both for bone and vessels with the 3μm acquisition. Tibia and mandibles bones were also used to show results that can be visually assessed. The largest portions of the vascular tree are orthogonal to the obtained slices of the bone. Therefore, the contrast agent appears as cylinders of various sizes.

Kevlar 49/Epoxy COPV Aging Evaluation

NASA Technical Reports Server (NTRS)

Sutter, James K.; Salem, Jonathan L.; Thesken, John C.; Russell, Richard W.; Littell, Justin; Ruggeri, Charles; Leifeste, Mark R.

2008-01-01

NASA initiated an effort to determine if the aging of Kevlar 49/Epoxy composite overwrapped pressure vessels (COPV) affected their performance. This study briefly reviews the history and certification of composite pressure vessels employed on NASA Orbiters. Tests to evaluate overwrap tensile strength changes compared 30 year old samples from Orbiter vessels to new Kevlar/Epoxy pressure vessel materials. Other tests include transverse compression and thermal analyses (glass transition and moduli). Results from these tests do not indicate a noticeable effect due to aging of the overwrap materials.

Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures.

PubMed

Casha, Aaron R; Camilleri, Liberato; Manché, Alexander; Gatt, Ruben; Attard, Daphne; Gauci, Marilyn; Camilleri-Podesta, Marie-Therese; Mcdonald, Stuart; Grima, Joseph N

2015-11-01

The human rib cage resembles a masonry dome in shape. Masonry domes have a particular construction that mimics stress distribution. Rib cortical thickness and bone density were analyzed to determine whether the morphology of the rib cage is sufficiently similar to a shell dome for internal rib structure to be predicted mathematically. A finite element analysis (FEA) simulation was used to measure stresses on the internal and external surfaces of a chest-shaped dome. Inner and outer rib cortical thickness and bone density were measured in the mid-axillary lines of seven cadaveric rib cages using computerized tomography scanning. Paired t tests and Pearson correlation were used to relate cortical thickness and bone density to stress. FEA modeling showed that the stress was 82% higher on the internal than the external surface, with a gradual decrease in internal and external wall stresses from the base to the apex. The inner cortex was more radio-dense, P < 0.001, and thicker, P < 0.001, than the outer cortex. Inner cortical thickness was related to internal stress, r = 0.94, P < 0.001, inner cortical bone density to internal stress, r = 0.87, P = 0.003, and outer cortical thickness to external stress, r = 0.65, P = 0.035. Mathematical models were developed relating internal and external cortical thicknesses and bone densities to rib level. The internal anatomical features of ribs, including the inner and outer cortical thicknesses and bone densities, are similar to the stress distribution in dome-shaped structures modeled using FEA computer simulations of a thick-walled dome pressure vessel. Fixation of rib fractures should include the stronger internal cortex. © 2015 Wiley Periodicals, Inc.

Diffusive oxygen shunting between vessels in the preglomerular renal vasculature: anatomic observations and computational modeling.

PubMed

Gardiner, Bruce S; Thompson, Sarah L; Ngo, Jennifer P; Smith, David W; Abdelkader, Amany; Broughton, Brad R S; Bertram, John F; Evans, Roger G

2012-09-01

To understand how geometric factors affect arterial-to-venous (AV) oxygen shunting, a mathematical model of diffusive oxygen transport in the renal cortex was developed. Preglomerular vascular geometry was investigated using light microscopy (providing vein shape, AV separation, and capillary density near arteries) and published micro-computed tomography (CT) data (providing vessel size and AV separation; Nordsletten DA, Blackett S, Bentley MD, Ritman EL, Smith NP. IUPS Physiome Project. http://www.physiome.org.nz/publications/nordsletten_blackett_ritman_bentley_smith_2005/folder_contents). A "U-shaped" relationship was observed between the arterial radius and the distance between the arterial and venous lumens. Veins were found to partially wrap around the artery more consistently for larger rather than smaller arteries. Intrarenal arteries were surrounded by an area of fibrous tissue, lacking capillaries, the thickness of which increased from ∼5 μm for the smallest arteries (<16-μm diameter) to ∼20 μm for the largest arteries (>200-μm diameter). Capillary density was greater near smaller arteries than larger arteries. No capillaries were observed between wrapped AV vessel pairs. The computational model comprised a single AV pair in cross section. Geometric parameters critical in renal oxygen transport were altered according to variations observed by CT and light microscopy. Lumen separation and wrapping of the vein around the artery were found to be the critical geometric factors determining the amount of oxygen shunted between AV pairs. AV oxygen shunting increases both as lumen separation decreases and as the degree of wrapping increases. The model also predicts that capillaries not only deliver oxygen, but can also remove oxygen from the cortical parenchyma close to an AV pair. Thus the presence of oxygen sinks (capillaries or tubules) near arteries would reduce the effectiveness of AV oxygen shunting. Collectively, these data suggest that AV oxygen shunting would be favored in larger vessels common to the cortical and medullary circulations (i.e., arcuate and proximal interlobular arteries) rather than the smaller vessels specific to the cortical circulation (distal interlobular arteries and afferent arterioles).

Buoyancy Driven Coolant Mixing Studies of Natural Circulation Flows at the ROCOM Test Facility Using ANSYS CFX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hohne, Thomas; Kliem, Soren; Rohde, Ulrich

2006-07-01

Coolant mixing in the cold leg, downcomer and the lower plenum of pressurized water reactors is an important phenomenon mitigating the reactivity insertion into the core. Therefore, mixing of the de-borated slugs with the ambient coolant in the reactor pressure vessel was investigated at the four loop 1:5 scaled ROCOM mixing test facility. Thermal hydraulics analyses showed, that weakly borated condensate can accumulate in particular in the pump loop seal of those loops, which do not receive safety injection. After refilling of the primary circuit, natural circulation in the stagnant loops can re-establish simultaneously and the de-borated slugs are shiftedmore » towards the reactor pressure vessel (RPV). In the ROCOM experiments, the length of the flow ramp and the initial density difference between the slugs and the ambient coolant was varied. From the test matrix experiments with 0 resp. 2% density difference between the de-borated slugs and the ambient coolant were used to validate the CFD software ANSYS CFX. To model the effects of turbulence on the mean flow a higher order Reynolds stress turbulence model was employed and a mesh consisting of 6.4 million hybrid elements was utilized. Only the experiments and CFD calculations with modeled density differences show a stratification in the downcomer. Depending on the degree of density differences the less dense slugs flow around the core barrel at the top of the downcomer. At the opposite side the lower borated coolant is entrained by the colder safety injection water and transported to the core. The validation proves that ANSYS CFX is able to simulate appropriately the flow field and mixing effects of coolant with different densities. (authors)« less

Relation of Cholesterol and Lipoprotein Parameters with Carotid Artery Plaque Characteristics: the Atherosclerosis Risk in Communities (ARIC) Carotid MRI Study

PubMed Central

Virani, Salim S.; Catellier, Diane J.; Pompeii, Lisa A.; Nambi, Vijay; Hoogeveen, Ron C.; Wasserman, Bruce A.; Coresh, Josef; Mosley, Thomas H.; Otvos, James D.; Sharrett, A. Richey; Boerwinkle, Eric; Ballantyne, Christie M.

2011-01-01

Objective There is a paucity of data regarding relations of apolipoproteins (apolipoprotein B [ApoB] and apolipoprotein A-1 [Apo A-1]), lipoprotein particle measures (low-density lipoprotein particle concentration [LDLp] and high-density lipoprotein particle concentration [HDLp]), and lipoprotein cholesterol measures (low-density lipoprotein cholesterol [LDL-C], non–high-density lipoprotein cholesterol [non– HDL-C], and high-density lipoprotein cholesterol [HDL-C]) with atherosclerotic plaque burden, plaque eccentricity, and lipid-rich core presence as a marker of high-risk plaques. Methods Carotid artery magnetic resonance imaging was performed in 1,670 Atherosclerosis Risk in Communities study participants. Vessel wall and lipid cores were measured; normalized wall index (NWI), standard deviation (SD) of wall thickness (measure of plaque eccentricity) were calculated; and lipid cores were detected in vessels with ≥1.5 mm thickness. Fasting concentrations of cholesterol, ApoB and Apo A-1, and LDLp and HDLp were measured. Results Measures of plaque burden (carotid wall volume, wall thickness, and NWI) were positively associated with atherogenic cholesterol and lipoproteins (p<0.05 for total cholesterol, LDL-C, non–HDL-C, ApoB, and LDLp), but not with HDL-C, Apo A-1, or HDLp. SD of wall thickness was associated with total cholesterol (p 0.01) and non-HDL-C (p 0.02). Although measures of atherogenic or anti-atherogenic cholesterol or lipoprotein were not individually associated with detection of a lipid-rich core, their ratios (total cholesterol/HDL-C, non–HDL-C/ HDL-C, and LDLp/HDLp) were associated with lipid-rich core presence (p≤0.05). Conclusion Extent of carotid atherosclerosis is associated with atherogenic cholesterol and lipoproteins. Atherogenic/anti-atherogenic cholesterol or particle ratios were associated with presence of a detectable lipid-rich core. PMID:21868017

Relation of cholesterol and lipoprotein parameters with carotid artery plaque characteristics: the Atherosclerosis Risk in Communities (ARIC) carotid MRI study.

PubMed

Virani, Salim S; Catellier, Diane J; Pompeii, Lisa A; Nambi, Vijay; Hoogeveen, Ron C; Wasserman, Bruce A; Coresh, Josef; Mosley, Thomas H; Otvos, James D; Sharrett, A Richey; Boerwinkle, Eric; Ballantyne, Christie M

2011-12-01

There is a paucity of data regarding relations of apolipoproteins (apolipoprotein B [ApoB] and apolipoprotein A-1 [Apo A-1]), lipoprotein particle measures (low-density lipoprotein particle concentration [LDLp] and high-density lipoprotein particle concentration [HDLp]), and lipoprotein cholesterol measures (low-density lipoprotein cholesterol [LDL-C], non-high-density lipoprotein cholesterol [non-HDL-C], and high-density lipoprotein cholesterol [HDL-C]) with atherosclerotic plaque burden, plaque eccentricity, and lipid-rich core presence as a marker of high-risk plaques. Carotid artery magnetic resonance imaging was performed in 1670 Atherosclerosis Risk in Communities study participants. Vessel wall and lipid cores were measured; normalized wall index (NWI), standard deviation (SD) of wall thickness (measure of plaque eccentricity) were calculated; and lipid cores were detected in vessels with ≥ 1.5mm thickness. Fasting concentrations of cholesterol, ApoB and Apo A-1, and LDLp and HDLp were measured. Measures of plaque burden (carotid wall volume, wall thickness, and NWI) were positively associated with atherogenic cholesterol and lipoproteins (p < 0.05 for total cholesterol, LDL-C, non-HDL-C, ApoB, and LDLp), but not with HDL-C, Apo A-1, or HDLp. SD of wall thickness was associated with total cholesterol (p 0.01) and non-HDL-C (p 0.02). Although measures of atherogenic or anti-atherogenic cholesterol or lipoprotein were not individually associated with detection of a lipid-rich core, their ratios (total cholesterol/HDL-C, non-HDL-C/HDL-C, and LDLp/HDLp) were associated with lipid-rich core presence (p ≤ 0.05). Extent of carotid atherosclerosis is associated with atherogenic cholesterol and lipoproteins. Atherogenic/anti-atherogenic cholesterol or particle ratios were associated with presence of a detectable lipid-rich core. Published by Elsevier Ireland Ltd.

Emission factors for gaseous and particulate pollutants from offshore diesel engine vessels in China

NASA Astrophysics Data System (ADS)

Zhang, Fan; Chen, Yingjun; Tian, Chongguo; Lou, Diming; Li, Jun; Zhang, Gan; Matthias, Volker

2016-05-01

Shipping emissions have significant influence on atmospheric environment as well as human health, especially in coastal areas and the harbour districts. However, the contribution of shipping emissions on the environment in China still need to be clarified especially based on measurement data, with the large number ownership of vessels and the rapid developments of ports, international trade and shipbuilding industry. Pollutants in the gaseous phase (carbon monoxide, sulfur dioxide, nitrogen oxides, total volatile organic compounds) and particle phase (particulate matter, organic carbon, elemental carbon, sulfates, nitrate, ammonia, metals) in the exhaust from three different diesel-engine-powered offshore vessels in China (350, 600 and 1600 kW) were measured in this study. Concentrations, fuel-based and power-based emission factors for various operating modes as well as the impact of engine speed on emissions were determined. Observed concentrations and emission factors for carbon monoxide, nitrogen oxides, total volatile organic compounds, and particulate matter were higher for the low-engine-power vessel (HH) than for the two higher-engine-power vessels (XYH and DFH); for instance, HH had NOx EF (emission factor) of 25.8 g kWh-1 compared to 7.14 and 6.97 g kWh-1 of DFH, and XYH, and PM EF of 2.09 g kWh-1 compared to 0.14 and 0.04 g kWh-1 of DFH, and XYH. Average emission factors for all pollutants except sulfur dioxide in the low-engine-power engineering vessel (HH) were significantly higher than that of the previous studies (such as 30.2 g kg-1 fuel of CO EF compared to 2.17 to 19.5 g kg-1 fuel in previous studies, 115 g kg-1 fuel of NOx EF compared to 22.3 to 87 g kg-1 fuel in previous studies and 9.40 g kg-1 fuel of PM EF compared to 1.2 to 7.6 g kg-1 fuel in previous studies), while for the two higher-engine-power vessels (DFH and XYH), most of the average emission factors for pollutants were comparable to the results of the previous studies, engine type was one of the most important influence factors for the differences. Emission factors for all three vessels were significantly different during different operating modes. Organic carbon and elemental carbon were the main components of particulate matter, while water-soluble ions and elements were present in trace amounts. The test inland ships and some test offshore vessels in China always had higher EFs for CO, NOx, and PM than previous studies. Besides, due to the significant influence of engine type on shipping emissions and that no accurate local EFs could be used in inventory calculation, much more measurement data for different vessels in China are still in urgent need. Best-fit engine speeds during actual operation should be based on both emission factors and economic costs.

Stacked Autoencoders for Outlier Detection in Over-the-Horizon Radar Signals

PubMed Central

Protopapadakis, Eftychios; Doulamis, Anastasios; Doulamis, Nikolaos; Dres, Dimitrios; Bimpas, Matthaios

2017-01-01

Detection of outliers in radar signals is a considerable challenge in maritime surveillance applications. High-Frequency Surface-Wave (HFSW) radars have attracted significant interest as potential tools for long-range target identification and outlier detection at over-the-horizon (OTH) distances. However, a number of disadvantages, such as their low spatial resolution and presence of clutter, have a negative impact on their accuracy. In this paper, we explore the applicability of deep learning techniques for detecting deviations from the norm in behavioral patterns of vessels (outliers) as they are tracked from an OTH radar. The proposed methodology exploits the nonlinear mapping capabilities of deep stacked autoencoders in combination with density-based clustering. A comparative experimental evaluation of the approach shows promising results in terms of the proposed methodology's performance. PMID:29312449

Does sterilization with fractionated electron beam irradiation prevent ACL tendon allograft from tissue damage?

PubMed

Schmidt, T; Grabau, D; Grotewohl, J H; Gohs, U; Pruß, A; Smith, M; Scheffler, S; Hoburg, A

2017-02-01

Allografts are frequently used for anterior cruciate ligament (ACL) reconstruction. However, due to the inherent risk of infection, a method that achieves complete sterilization of grafts is warranted without impairing their biomechanical properties. Fractionation of electron beam (FEbeam) irradiation has been shown to maintain similar biomechanical properties compared to fresh-frozen allografts (FFA) in vitro. Therefore, aim of this study was to evaluate the biomechanical properties and early remodelling of grafts that were sterilized with fractionated high-dose electron beam irradiation in an in vivo sheep model. ACL reconstruction was performed in 18 mature merino mix sheep. Sixteen were reconstructed with allografts sterilized with FEbeam irradiation (8 × 3.4 kGy) and two with FFA. Eight FFA from prior studies with identical surgical reconstruction and biomechanical and histological analyzes served as controls. Half of the animals were sacrificed at 6 and 12 weeks, and biomechanical testing was performed. Anterior-posterior laxity (APL) was assessed with an AP drawer test at 60° flexion, and load to failure testing was carried out. Histological evaluation of mid-substance samples was performed for descriptive analysis, cell count, crimp and vessel density. For statistical analysis a Kruskal-Wallis test was used for overall group comparison followed by a Mann-Whitney U test for pairwise comparison of the histological and biomechanical parameters. Biomechanical testing showed significantly decreased stiffness in FEbeam compared to FFA at both time points (p ≤ 0.004). APL was increased in FEbeam compared to FFA, which was significant at 6 weeks (p = 0.004). Median of failure loads was decreased in FEbeam grafts, with 12 reconstructions already failing during cyclic loading. Vessel density was decreased in FEbeam compared to FFA at both time points, with significant differences at 12 weeks (p = 0.015). Crimp length was significantly shorter in FEbeam compared to FFA at both time points (p ≤ 0.004) and decreased significantly in both groups from 6 to 12 weeks (p ≤ 0.025). ACL reconstruction with fractionated Ebeam sterilization significantly alters the biomechanical properties and the early remodelling process of treated grafts in vivo. Therefore, this sterilization method cannot be recommended for clinical application. As substantial changes in the remodelling are inherent in this study, care in the rehabilitation of even low-dose sterilized allografts, used for ACL reconstruction, is recommended.

Structural considerations in design of lightweight glass-fiber composite pressure vessels

NASA Technical Reports Server (NTRS)

Faddoul, J. R.

1973-01-01

The development of structurally efficient, metal-lined, glass-fiber composite pressure vessels. Both the current state-of-the-art and current problems are discussed along with fracture mechanics considerations for the metal liner. The design concepts used for metal-lined, glass-fiber, composite pressure vessels are described and the structural characteristics of the composite designs are compared with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. Results of a current program to evaluate flaw growth and fracture characteristics of the metal liners are reviewed and the impact of these results on composite pressure vessel designs is discussed.

Therapeutic lymphangiogenesis ameliorates established acute lung allograft rejection

PubMed Central

Cui, Ye; Liu, Kaifeng; Monzon-Medina, Maria E.; Padera, Robert F.; Wang, Hao; George, Gautam; Toprak, Demet; Abdelnour, Elie; D’Agostino, Emmanuel; Goldberg, Hilary J.; Perrella, Mark A.; Forteza, Rosanna Malbran; Rosas, Ivan O.; Visner, Gary; El-Chemaly, Souheil

2015-01-01

Lung transplantation is the only viable option for patients suffering from otherwise incurable end-stage pulmonary diseases such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis. Despite aggressive immunosuppression, acute rejection of the lung allograft occurs in over half of transplant recipients, and the factors that promote lung acceptance are poorly understood. The contribution of lymphatic vessels to transplant pathophysiology remains controversial, and data that directly address the exact roles of lymphatic vessels in lung allograft function and survival are limited. Here, we have shown that there is a marked decline in the density of lymphatic vessels, accompanied by accumulation of low-MW hyaluronan (HA) in mouse orthotopic allografts undergoing rejection. We found that stimulation of lymphangiogenesis with VEGF-C156S, a mutant form of VEGF-C with selective VEGFR-3 binding, alleviates an established rejection response and improves clearance of HA from the lung allograft. Longitudinal analysis of transbronchial biopsies from human lung transplant recipients demonstrated an association between resolution of acute lung rejection and decreased HA in the graft tissue. Taken together, these results indicate that lymphatic vessel formation after lung transplantation mediates HA drainage and suggest that treatments to stimulate lymphangiogenesis have promise for improving graft outcomes. PMID:26485284

Structural response of 1/20-scale models of the Clinch River Breeder Reactor to a simulated hypothetical core disruptive accident. Technical report 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romander, C. M.; Cagliostro, D. J.

Five experiments were performed to help evaluate the structural integrity of the reactor vessel and head design and to verify code predictions. In the first experiment (SM 1), a detailed model of the head was loaded statically to determine its stiffness. In the remaining four experiments (SM 2 to SM 5), models of the vessel and head were loaded dynamically under a simulated 661 MW-sec hypothetical core disruptive accident (HCDA). Models SM 2 to SM 4, each of increasing complexity, systematically showed the effects of upper internals structures, a thermal liner, core support platform, and torospherical bottom on vessel response.more » Model SM 5, identical to SM 4 but more heavily instrumented, demonstrated experimental reproducibility and provided more comprehensive data. The models consisted of a Ni 200 vessel and core barrel, a head with shielding and simulated component masses, an upper internals structure (UIS), and, in the more complex models SM 4 and SM 5, a Ni 200 thermal liner and core support structure. Water simulated the liquid sodium coolant and a low-density explosive simulated the HCDA loads.« less

Enhanced AIS receiver design for satellite reception

NASA Astrophysics Data System (ADS)

Clazzer, Federico; Lázaro, Francisco; Plass, Simon

2016-12-01

The possibility to detect Automatic Identification System (AIS) messages from low earth orbit (LEO) satellites paves the road for a plurality of new and unexplored services. Besides worldwide tracking of vessels, maritime traffic monitoring, analysis of vessel routes employing big data, and oceans monitoring are just few of the fields, where satellite-aided AIS is beneficial. Designed for ship-to-ship communication and collision avoidance, AIS satellite reception performs poorly in regions with a high density of vessels. This calls for the development of advanced satellite AIS receivers able to improve the decoding capabilities. In this context, our contribution focuses on the introduction of a new enhanced AIS receiver design and its performance evaluation. The enhanced receiver makes use of a coherent receiver for the low signal-to-noise ratio (SNR) region, while for medium to high SNRs, a differential Viterbi receiver is used. Additional novelty of our work is in the exploitation of previously decoded packets from one vessel that is still under the LEO reception range, to improve the vessel detection probability. The assessment of the performance against a common receiver is done making the use of a simple and tight model of the medium access (MAC) layer and the multi-packet reception (MPR) matrix for physical layer (PHY) representation. Performance results show the benefits of such enhanced receiver, especially when it is bundled with successive interference cancellation (SIC).

Enzalutamide and CXCR7 inhibitor combination treatment suppresses cell growth and angiogenic signaling in castration‐resistant prostate cancer models

PubMed Central

Luo, Yong; Azad, Abul Kalam; Karanika, Styliani; Basourakos, Spyridon P.; Zuo, Xuemei; Wang, Jianxiang; Yang, Luan; Yang, Guang; Korentzelos, Dimitrios; Yin, Jianhua; Park, Sanghee; Zhang, Penglie; Campbell, James J.; Schall, Thomas J.; Cao, Guangwen; Li, Likun

2018-01-01

Previous studies have shown that increased levels of chemokine receptor CXCR7 are associated with the increased invasiveness of prostate cancer cells. We now show that CXCR7 expression is upregulated in VCaP and C4‐2B cells after enzalutamide (ENZ) treatment. ENZ treatment induced apoptosis (sub‐G1) in VCaP and C4‐2B cells, and this effect was further increased after combination treatment with ENZ and CCX771, a specific CXCR7 inhibitor. The levels of p‐EGFR (Y1068), p‐AKT (T308) and VEGFR2 were reduced after ENZ and CCX771 combination treatment compared to single agent treatment. In addition, significantly greater reductions in migration were shown after combination treatment compared to those of single agents or vehicle controls, and importantly, similar reductions in the levels of secreted VEGF were also demonstrated. Orthotopic VCaP xenograft growth and subcutaneous MDA133‐4 patient‐derived xenograft (PDX) tumor growth was reduced by single agent treatment, but significantly greater suppression was observed in the combination treatment group. Although overall microvessel densities in the tumor tissues were not different among the different treatment groups, a significant reduction in large blood vessels (>100 μm2) was observed in tumors following combination treatment. Apoptotic indices in tumor tissues were significantly increased following combination treatment compared with vehicle control‐treated tumor tissues. Our results demonstrate that significant tumor suppression mediated by ENZ and CXCR7 combination treatment may be due, in part, to reductions in proangiogenic signaling and in the formation of large blood vessels in prostate cancer tumors. PMID:29277895

A comparative analysis of the cryo-compression and cryo-adsorption hydrogen storage methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petitpas, G; Benard, P; Klebanoff, L E

2014-07-01

While conventional low-pressure LH₂ dewars have existed for decades, advanced methods of cryogenic hydrogen storage have recently been developed. These advanced methods are cryo-compression and cryo-adsorption hydrogen storage, which operate best in the temperature range 30–100 K. We present a comparative analysis of both approaches for cryogenic hydrogen storage, examining how pressure and/or sorbent materials are used to effectively increase onboard H₂ density and dormancy. We start by reviewing some basic aspects of LH₂ properties and conventional means of storing it. From there we describe the cryo-compression and cryo-adsorption hydrogen storage methods, and then explore the relationship between them, clarifyingmore » the materials science and physics of the two approaches in trying to solve the same hydrogen storage task (~5–8 kg H₂, typical of light duty vehicles). Assuming that the balance of plant and the available volume for the storage system in the vehicle are identical for both approaches, the comparison focuses on how the respective storage capacities, vessel weight and dormancy vary as a function of temperature, pressure and type of cryo-adsorption material (especially, powder MOF-5 and MIL-101). By performing a comparative analysis, we clarify the science of each approach individually, identify the regimes where the attributes of each can be maximized, elucidate the properties of these systems during refueling, and probe the possible benefits of a combined “hybrid” system with both cryo-adsorption and cryo-compression phenomena operating at the same time. In addition the relationships found between onboard H₂ capacity, pressure vessel and/or sorbent mass and dormancy as a function of rated pressure, type of sorbent material and fueling conditions are useful as general designing guidelines in future engineering efforts using these two hydrogen storage approaches.« less

Effect of nonparallel placement of in-circle bipolar radiofrequency ablation probes on volume of tissue ablated with heat sink.

PubMed

Pillai, Krishna; Al-Alem, Ihssan; Akhter, Javed; Chua, Terence C; Shehata, Mena; Morris, David L

2015-06-01

Percutaneous bipolar radiofrequency ablation (RFA) is a minimally invasive technique for treating liver tumors. It is not always possible to insert the bipolar probes parallel to each other on either side of tumor, since it restricts maneuverability away from vital structures or ablate certain tumor shape. Therefore, we investigated how nonparallel placement of probes affected ablation. Bipolar RFA in parallel and in divergent positions were submerged in tissue model (800 mL egg white) at 37°C and ablated. Temperature probes, T1 and T2 were placed 8.00 mm below the tip of the probes, T3 in between the probe coil elements and T4 and T5 at water inlet and outlet, respectively. Both models with heat sink (+HS) and without (-HS) were investigated. The mean ablated tissue volume, mass, density and height increased linearly with unit angle increase for -HS model. With +HS, a smaller increase in mean volume and mass, a slightly greater increase in mean density but a reduction in height of tissue was seen. The mean ablation time and duration of maximum temperature with +HS was slightly larger, compared with -HS, while -HS ablated at a slightly higher temperature. The heat sink present was minimal for probes in parallel position compared to nonparallel positions. Divergence from parallel insertion of bipolar RFA probes increased the mean volume, mass, and density of tissue ablated. However, the presence of large heat sinks may limit the application of this technique, when tumors border on larger vessels. © The Author(s) 2014.

A Chinese 2-herb formula (NF3) promotes hindlimb ischemia-induced neovascularization and wound healing of diabetic rats.

PubMed

Tam, Jacqueline Chor-Wing; Ko, Chun-Hay; Lau, Kit-Man; To, Ming-Ho; Kwok, Hin-Fai; Chan, Yuet-Wa; Siu, Wing-Sum; Etienne-Selloum, Nelly; Lau, Ching-Po; Chan, Wai-Yee; Leung, Ping-Chung; Fung, Kwok-Pui; Schini-Kerth, Valérie B; Lau, Clara Bik-San

2014-01-01

Diabetic foot ulcer is closely associated with peripheral vascular disease. Enhancement of tissue oxidative stress, reduction of nitric oxide (NO) and angiogenic growth factors, and abnormal matrix metalloproteinase (MMP) activity are pathophysiological factors in post-ischemic neovascularization and diabetic wound healing. Our previous study demonstrated that the Chinese 2-herb formula, NF3, showed significant wound healing effects on diabetic foot ulcer rats. A novel rat diabetic foot ulcer with hindlimb ischemia model was established in order to strengthen our claims on the diabetic wound healing and post-ischemic neovascularization effects of NF3. Our results demonstrate that NF3 can significantly reduce the wound area of the diabetic foot ulcer rat with hindlimb ischemia by 21.6% (p<0.05) compared with the control group. In addition, flow cytometric analysis revealed that NF3 could boost circulating EPC levels for local wound vessel incorporation. Immunohistochemical analysis showed that NF3 could significantly augment blood vessel density, VEGF and eNOS expression, and attenuate tissue oxidative stress of ischemic muscles (p<0.001). NF3 significantly stimulated MMP activity involved in angiogenesis. Our study shows, for the first time, the beneficial effects of NF3 in wound healing and post-ischemic neovascularization in diabetes. Copyright © 2014 Elsevier Inc. All rights reserved.

A comparison of hydraulic architecture in three similarly sized woody species differing in their maximum potential height.

PubMed

McCulloh, Katherine A; Johnson, Daniel M; Petitmermet, Joshua; McNellis, Brandon; Meinzer, Frederick C; Lachenbruch, Barbara

2015-07-01

The physiological mechanisms underlying the short maximum height of shrubs are not understood. One possible explanation is that differences in the hydraulic architecture of shrubs compared with co-occurring taller trees prevent the shrubs from growing taller. To explore this hypothesis, we examined various hydraulic parameters, including vessel lumen diameter, hydraulic conductivity and vulnerability to drought-induced embolism, of three co-occurring species that differed in their maximum potential height. We examined one species of shrub, one short-statured tree and one taller tree. We worked with individuals that were approximately the same age and height, which was near the maximum for the shrub species. A number of variables correlated with the maximum potential height of the species. For example, vessel diameter and vulnerability to embolism both increased while wood density declined with maximum potential height. The difference between the pressure causing 50% reduction in hydraulic conductance in the leaves and the midday leaf water potential (the leaf's hydraulic safety margin) was much larger in the shrub than the other two species. In general, trends were consistent with understory shrubs having a more conservative life history strategy than co-occurring taller species. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Transcriptional profiling of CD31(+) cells isolated from murine embryonic stem cells.

PubMed

Mariappan, Devi; Winkler, Johannes; Chen, Shuhua; Schulz, Herbert; Hescheler, Jürgen; Sachinidis, Agapios

2009-02-01

Identification of genes involved in endothelial differentiation is of great interest for the understanding of the cellular and molecular mechanisms involved in the development of new blood vessels. Mouse embryonic stem (mES) cells serve as a potential source of endothelial cells for transcriptomic analysis. We isolated endothelial cells from 8-days old embryoid bodies by immuno-magnetic separation using platelet endothelial cell adhesion molecule-1 (also known as CD31) expressed on both early and mature endothelial cells. CD31(+) cells exhibit endothelial-like behavior by being able to incorporate DiI-labeled acetylated low-density lipoprotein as well as form tubular structures on matrigel. Quantitative and semi-quantitative PCR analysis further demonstrated the increased expression of endothelial transcripts. To ascertain the specific transcriptomic identity of the CD31(+) cells, large-scale microarray analysis was carried out. Comparative bioinformatic analysis reveals an enrichment of the gene ontology categories angiogenesis, blood vessel morphogenesis, vasculogenesis and blood coagulation in the CD31(+) cell population. Based on the transcriptomic signatures of the CD31(+) cells, we conclude that this ES cell-derived population contains endothelial-like cells expressing a mesodermal marker BMP2 and possess an angiogenic potential. The transcriptomic characterization of CD31(+) cells enables an in vitro functional genomic model to identify genes required for angiogenesis.

Fluorescence imaging of angiogenesis in green fluorescent protein-expressing tumors

NASA Astrophysics Data System (ADS)

Yang, Meng; Baranov, Eugene; Jiang, Ping; Li, Xiao-Ming; Wang, Jin W.; Li, Lingna; Yagi, Shigeo; Moossa, A. R.; Hoffman, Robert M.

2002-05-01

The development of therapeutics for the control of tumor angiogenesis requires a simple, reliable in vivo assay for tumor-induced vascularization. For this purpose, we have adapted the orthotopic implantation model of angiogenesis by using human and rodent tumors genetically tagged with Aequorea victoria green fluorescent protein (GFP) for grafting into nude mice. Genetically-fluorescent tumors can be readily imaged in vivo. The non-luminous induced capillaries are clearly visible against the bright tumor fluorescence examined either intravitally or by whole-body luminance in real time. Fluorescence shadowing replaces the laborious histological techniques for determining blood vessel density. High-level GFP-expressing tumor cell lines made it possible to acquire the high-resolution real-time fluorescent optical images of angiogenesis in both primary tumors and their metastatic lesions in various human and rodent tumor models by means of a light-based imaging system. Intravital images of angiogenesis onset and development were acquired and quantified from a GFP- expressing orthotopically-growing human prostate tumor over a 19-day period. Whole-body optical imaging visualized vessel density increasing linearly over a 20-week period in orthotopically-growing, GFP-expressing human breast tumor MDA-MB-435. Vessels in an orthotopically-growing GFP- expressing Lewis lung carcinoma tumor were visualized through the chest wall via a reversible skin flap. These clinically-relevant angiogenesis mouse models can be used for real-time in vivo evaluation of agents inhibiting or promoting tumor angiogenesis in physiological micro- environments.

Review: Cerebral microvascular pathology in aging and neurodegeneration

PubMed Central

Brown, William R.; Thore, Clara R.

2010-01-01

This review of age-related brain microvascular pathologies focuses on topics studied by this laboratory, including anatomy of the blood supply, tortuous vessels, venous collagenosis, capillary remnants, vascular density, and microembolic brain injury. Our studies feature thick sections, large blocks embedded in celloidin, and vascular staining by alkaline phosphatase (AP). This permits study of the vascular network in three dimensions, and the differentiation of afferent from efferent vessels. Current evidence suggests that there is decreased vascular density in aging, Alzheimer’s disease (AD), and leukoaraiosis (LA), and cerebrovascular dysfunction precedes and accompanies cognitive dysfunction and neurodegeneration. A decline in cerebrovascular angiogenesis may inhibit recovery from hypoxia-induced capillary loss. Cerebral blood flow (CBF) is inhibited by tortuous arterioles and deposition of excessive collagen in veins and venules. Misery perfusion due to capillary loss appears to occur before cell loss in LA, and CBF is also reduced in the normal-appearing white matter. Hypoperfusion occurs early in AD, inducing white matter lesions and correlating with dementia. In vascular dementia, cholinergic reductions are correlated with cognitive impairment, and cholinesterase inhibitors have some benefit. Most lipid microemboli from cardiac surgery pass through the brain in a few days, but some remain for weeks. They can cause what appears to be a type of vascular dementia years after surgery. Donepezil has shown some benefit. Emboli, such as clots, cholesterol crystals, and microspheres can be extruded through the walls of cerebral vessels, but there is no evidence yet that lipid emboli undergo such extravasation. PMID:20946471

Anatomical features associated with water transport in imperforate tracheary elements of vessel-bearing angiosperms

PubMed Central

Sano, Yuzou; Morris, Hugh; Shimada, Hiroshi; Ronse De Craene, Louis P.; Jansen, Steven

2011-01-01

Background and Aims Imperforate tracheary elements (ITEs) in wood of vessel-bearing angiosperms may or may not transport water. Despite the significance of hydraulic transport for defining ITE types, the combination of cell structure with water transport visualization in planta has received little attention. This study provides a quantitative analysis of structural features associated with the conductive vs. non-conductive nature of ITEs. Methods Visualization of water transport was studied in 15 angiosperm species by dye injection and cryo-scanning electron microscopy. Structural features of ITEs were examined using light and electron microscopy. Key Results ITEs connected to each other by pit pairs with complete pit membranes contributed to water transport, while cells showing pit membranes with perforations up to 2 µm were hydraulically not functional. A close relationship was found between pit diameter and pit density, with both characters significantly higher in conductive than in non-conductive cells. In species with both conductive and non-conductive ITEs, a larger diameter was characteristic of the conductive cells. Water transport showed no apparent relationship with the length of ITEs and vessel grouping. Conclusions The structure and density of pits between ITEs represent the main anatomical characters determining water transport. The pit membrane structure of ITEs provides a reliable, but practically challenging, criterion to determine their conductive status. It is suggested that the term tracheids should strictly be used for conductive ITEs, while fibre-tracheids and libriform fibres are non-conductive. PMID:21385773

Highly efficient nonrigid motion‐corrected 3D whole‐heart coronary vessel wall imaging

PubMed Central

Atkinson, David; Henningsson, Markus; Botnar, Rene M.; Prieto, Claudia

2016-01-01

Purpose To develop a respiratory motion correction framework to accelerate free‐breathing three‐dimensional (3D) whole‐heart coronary lumen and coronary vessel wall MRI. Methods We developed a 3D flow‐independent approach for vessel wall imaging based on the subtraction of data with and without T2‐preparation prepulses acquired interleaved with image navigators. The proposed method corrects both datasets to the same respiratory position using beat‐to‐beat translation and bin‐to‐bin nonrigid corrections, producing coregistered, motion‐corrected coronary lumen and coronary vessel wall images. The proposed method was studied in 10 healthy subjects and was compared with beat‐to‐beat translational correction (TC) and no motion correction for the left and right coronary arteries. Additionally, the coronary lumen images were compared with a 6‐mm diaphragmatic navigator gated and tracked scan. Results No significant differences (P > 0.01) were found between the proposed method and the gated and tracked scan for coronary lumen, despite an average improvement in scan efficiency to 96% from 59%. Significant differences (P < 0.01) were found in right coronary artery vessel wall thickness, right coronary artery vessel wall sharpness, and vessel wall visual score between the proposed method and TC. Conclusion The feasibility of a highly efficient motion correction framework for simultaneous whole‐heart coronary lumen and vessel wall has been demonstrated. Magn Reson Med 77:1894–1908, 2017. © 2016 International Society for Magnetic Resonance in Medicine PMID:27221073

50 CFR 300.209 - Alternative procedures for nations identified as having vessels engaged in shark catch that are...

Code of Federal Regulations, 2014 CFR

2014-10-01

... identified as having vessels engaged in shark catch that are not certified in this subpart. 300.209 Section... identified as having vessels engaged in shark catch that are not certified in this subpart. (a) These... not target or incidentally catch sharks, or were harvested by practices that— (1) Are comparable to...

50 CFR 300.209 - Alternative procedures for nations identified as having vessels engaged in shark catch that are...

Code of Federal Regulations, 2013 CFR

2013-10-01

... identified as having vessels engaged in shark catch that are not certified in this subpart. 300.209 Section... identified as having vessels engaged in shark catch that are not certified in this subpart. (a) These... not target or incidentally catch sharks, or were harvested by practices that— (1) Are comparable to...

Characterization of cardiac quiescence from retrospective cardiac computed tomography using a correlation-based phase-to-phase deviation measure

PubMed Central

Wick, Carson A.; McClellan, James H.; Arepalli, Chesnal D.; Auffermann, William F.; Henry, Travis S.; Khosa, Faisal; Coy, Adam M.; Tridandapani, Srini

2015-01-01

Purpose: Accurate knowledge of cardiac quiescence is crucial to the performance of many cardiac imaging modalities, including computed tomography coronary angiography (CTCA). To accurately quantify quiescence, a method for detecting the quiescent periods of the heart from retrospective cardiac computed tomography (CT) using a correlation-based, phase-to-phase deviation measure was developed. Methods: Retrospective cardiac CT data were obtained from 20 patients (11 male, 9 female, 33–74 yr) and the left main, left anterior descending, left circumflex, right coronary artery (RCA), and interventricular septum (IVS) were segmented for each phase using a semiautomated technique. Cardiac motion of individual coronary vessels as well as the IVS was calculated using phase-to-phase deviation. As an easily identifiable feature, the IVS was analyzed to assess how well it predicts vessel quiescence. Finally, the diagnostic quality of the reconstructed volumes from the quiescent phases determined using the deviation measure from the vessels in aggregate and the IVS was compared to that from quiescent phases calculated by the CT scanner. Three board-certified radiologists, fellowship-trained in cardiothoracic imaging, graded the diagnostic quality of the reconstructions using a Likert response format: 1 = excellent, 2 = good, 3 = adequate, 4 = nondiagnostic. Results: Systolic and diastolic quiescent periods were identified for each subject from the vessel motion calculated using the phase-to-phase deviation measure. The motion of the IVS was found to be similar to the aggregate vessel (AGG) motion. The diagnostic quality of the coronary vessels for the quiescent phases calculated from the aggregate vessel (PAGG) and IVS (PIV S) deviation signal using the proposed methods was comparable to the quiescent phases calculated by the CT scanner (PCT). The one exception was the RCA, which improved for PAGG for 18 of the 20 subjects when compared to PCT (PCT = 2.48; PAGG = 2.07, p = 0.001). Conclusions: A method for quantifying the motion of specific coronary vessels using a correlation-based, phase-to-phase deviation measure was developed and tested on 20 patients receiving cardiac CT exams. The IVS was found to be a suitable predictor of vessel quiescence. The diagnostic quality of the quiescent phases detected by the proposed methods was comparable to those calculated by the CT scanner. The ability to quantify coronary vessel quiescence from the motion of the IVS can be used to develop new CTCA gating techniques and quantify the resulting potential improvement in CTCA image quality. PMID:25652511

Characterization of cardiac quiescence from retrospective cardiac computed tomography using a correlation-based phase-to-phase deviation measure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wick, Carson A.; McClellan, James H.; Arepalli, Chesnal D.

2015-02-15

Purpose: Accurate knowledge of cardiac quiescence is crucial to the performance of many cardiac imaging modalities, including computed tomography coronary angiography (CTCA). To accurately quantify quiescence, a method for detecting the quiescent periods of the heart from retrospective cardiac computed tomography (CT) using a correlation-based, phase-to-phase deviation measure was developed. Methods: Retrospective cardiac CT data were obtained from 20 patients (11 male, 9 female, 33–74 yr) and the left main, left anterior descending, left circumflex, right coronary artery (RCA), and interventricular septum (IVS) were segmented for each phase using a semiautomated technique. Cardiac motion of individual coronary vessels as wellmore » as the IVS was calculated using phase-to-phase deviation. As an easily identifiable feature, the IVS was analyzed to assess how well it predicts vessel quiescence. Finally, the diagnostic quality of the reconstructed volumes from the quiescent phases determined using the deviation measure from the vessels in aggregate and the IVS was compared to that from quiescent phases calculated by the CT scanner. Three board-certified radiologists, fellowship-trained in cardiothoracic imaging, graded the diagnostic quality of the reconstructions using a Likert response format: 1 = excellent, 2 = good, 3 = adequate, 4 = nondiagnostic. Results: Systolic and diastolic quiescent periods were identified for each subject from the vessel motion calculated using the phase-to-phase deviation measure. The motion of the IVS was found to be similar to the aggregate vessel (AGG) motion. The diagnostic quality of the coronary vessels for the quiescent phases calculated from the aggregate vessel (P{sub AGG}) and IVS (P{sub IV} {sub S}) deviation signal using the proposed methods was comparable to the quiescent phases calculated by the CT scanner (P{sub CT}). The one exception was the RCA, which improved for P{sub AGG} for 18 of the 20 subjects when compared to P{sub CT} (P{sub CT} = 2.48; P{sub AGG} = 2.07, p = 0.001). Conclusions: A method for quantifying the motion of specific coronary vessels using a correlation-based, phase-to-phase deviation measure was developed and tested on 20 patients receiving cardiac CT exams. The IVS was found to be a suitable predictor of vessel quiescence. The diagnostic quality of the quiescent phases detected by the proposed methods was comparable to those calculated by the CT scanner. The ability to quantify coronary vessel quiescence from the motion of the IVS can be used to develop new CTCA gating techniques and quantify the resulting potential improvement in CTCA image quality.« less

Retinal vessel diameters and reactivity in diabetes mellitus and/or cardiovascular disease.

PubMed

Heitmar, R; Lip, G Y H; Ryder, R E; Blann, A D

2017-04-26

Retinal vessel calibre and vascular dilation/constriction in response to flicker light provocation may provide a measure distinguishing patients suffering from diabetes mellitus and/or cardiovascular disease. One hundred and sixteen age and sex matched patients with diabetes mellitus (DM), cardiovascular disease (CVD) and both DM and CVD (DM + CVD) underwent systemic and intraocular pressure measurements. Retinal vessel calibres were assessed using a validated computer-based program to compute central retinal artery and vein equivalents (CRVE) from monochromatic retinal images. Vessel dilation and constriction responses to flicker light provocation were assessed by continuous retinal vessel diameter recordings. Plasma endothelial markers von Willebrand factor (vWf) and soluble E selectin (sEsel) were measured by ELISA. Retinal vessel calibres were comparable across groups but CRVE correlated significantly with disease duration in DM patients (r = 0.57, p < 0.001). Patients suffering DM only exhibited reduced arterial vasomotion at rest and reduced arterial constriction following flicker light induced vessel dilation compared to patients with CVD and those suffering both CVD + DM (p = 0.030). Patients suffering from CVD + DM exhibited significant differences between each flicker cycle in regards to arterial maximum constriction (p = 0.006) and time needed to reach arterial maximum dilation (p = 0.004), whereas the other two groups did not show such inconsistencies between individual flicker cycles. vWf was raised in CVD + DM compared to the other two groups (p ≤ 0.02), whilst sEsel was raised in CVD + DM compared to DM alone (p = 0.044). Dynamic retinal vascular calibres as obtained by continuous diameter measurements using flicker light provocation can reveal subtle differences between groups suffering from CVD with and without DM. This difference in reaction pattern and lack of arterial constriction in DM may provide a suitable marker to monitor progression.

Method for the generation of variable density metal vapors which bypasses the liquidus phase

DOEpatents

Kunnmann, Walter; Larese, John Z.

2001-01-01

The present invention provides a method for producing a metal vapor that includes the steps of combining a metal and graphite in a vessel to form a mixture; heating the mixture to a first temperature in an argon gas atmosphere to form a metal carbide; maintaining the first temperature for a period of time; heating the metal carbide to a second temperature to form a metal vapor; withdrawing the metal vapor and the argon gas from the vessel; and separating the metal vapor from the argon gas. Metal vapors made using this method can be used to produce uniform powders of the metal oxide that have narrow size distribution and high purity.

Come On Down! Galapagos Rift Expedition--Grades 7-8. Overview: Ocean Exploration.

ERIC Educational Resources Information Center

National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

These activities are designed to teach about ocean exploration. Students are expected to research the development and implementation of a research vessel/vehicle used for deep ocean exploration, calculate the density of objects by determining the mass and volume, and construct a device that exhibits neutral buoyancy. The activity provides learning…

Scaling and design analyses of a scaled-down, high-temperature test facility for experimental investigation of the initial stages of a VHTR air-ingress accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arcilesi, David J.; Ham, Tae Kyu; Kim, In Hun

2015-07-01

A critical event in the safety analysis of the very high-temperature gas-cooled reactor (VHTR) is an air-ingress accident. This accident is initiated, in its worst case scenario, by a double-ended guillotine break of the coaxial cross vessel, which leads to a rapid reactor vessel depressurization. In a VHTR, the reactor vessel is located within a reactor cavity that is filled with air during normal operating conditions. Following the vessel depressurization, the dominant mode of ingress of an air–helium mixture into the reactor vessel will either be molecular diffusion or density-driven stratified flow. The mode of ingress is hypothesized to dependmore » largely on the break conditions of the cross vessel. Since the time scales of these two ingress phenomena differ by orders of magnitude, it is imperative to understand under which conditions each of these mechanisms will dominate in the air ingress process. Computer models have been developed to analyze this type of accident scenario. There are, however, limited experimental data available to understand the phenomenology of the air-ingress accident and to validate these models. Therefore, there is a need to design and construct a scaled-down experimental test facility to simulate the air-ingress accident scenarios and to collect experimental data. The current paper focuses on the analyses performed for the design and operation of a 1/8th geometric scale (by height and diameter), high-temperature test facility. A geometric scaling analysis for the VHTR, a time scale analysis of the air-ingress phenomenon, a transient depressurization analysis of the reactor vessel, a hydraulic similarity analysis of the test facility, a heat transfer characterization of the hot plenum, a power scaling analysis for the reactor system, and a design analysis of the containment vessel are discussed.« less

Proper Calcium Use: Vitamin K2 as a Promoter of Bone and Cardiovascular Health.

PubMed

Maresz, Katarzyna

2015-02-01

Inadequate calcium intake can lead to decreased bone mineral density, which can increase the risk of bone fractures. Supplemental calcium promotes bone mineral density and strength and can prevent osteoporosis. Recent scientific evidence, however, suggests that elevated consumption of calcium supplements may raise the risk for heart disease and can be connected with accelerated deposit of calcium in blood-vessel walls and soft tissues. In contrast, vitamin K2 is associated with the inhibition of arterial calcification and arterial stiffening. An adequate intake of vitamin K2 has been shown to lower the risk of vascular damage because it activates matrix GLA protein (MGP), which inhibits the deposits of calcium on the walls. Vitamin K, particularly as vitamin K2, is nearly nonexistent in junk food, with little being consumed even in a healthy Western diet. Vitamin K deficiency results in inadequate activation of MGP, which greatly impairs the process of calcium removal and increases the risk of calcification of the blood vessels. An increased intake of vitamin K2 could be a means of lowering calcium-associated health risks.

Detection and imaging of the reconstituted pyropheophorbide-cholesterol oleate labeled low-density lipoprotein in the HepG2 tumor

NASA Astrophysics Data System (ADS)

Blessington, Dana M.; Zhang, Zhihong; Li, Hui; Zhang, Min; Zhou, Lanlan; Glickson, Jerry D.; Zheng, Gang; Chance, Britton

2003-07-01

We utilized the nude mouse model bearing the human hepatoblastoma G2 (HepG2) tumor and B-16 Murine Melanoma tumor to study the delivery and detection of the reconstituted Pyropheophorbide Cholesterol Oleate (r-pyroCE) molecular beacon. The delivery vehicle, low-density lipoprotein (LDL), labeled with the porphyrin derivative, was employed in response of the overexpression of LDL receptors in the HepG2 tumor. The B-16 melanoma tumor was also observed in this study for its overexpression of the LDL receptors. The tumors were imaged using the 3D low temperature scanner to produce images throughout several sliced sections of each tumor. The fluorescence signal of the pyropheophorbide was detected at 720nm when excited at 670nm in the tumor tissue. The uniform distribution of the signal in the HepG2 tumor shows extravasation of the beacon from the blood vessels. The B-16 tumor did not exhibit strong fluorescent signals and successful delivery as the HepG2 tumor outside the blood vessels and into the tumor tissue.

On the Analysis of Clustering in an Irradiated Low Alloy Reactor Pressure Vessel Steel Weld.

PubMed

Lindgren, Kristina; Stiller, Krystyna; Efsing, Pål; Thuvander, Mattias

2017-04-01

Radiation induced clustering affects the mechanical properties, that is the ductile to brittle transition temperature (DBTT), of reactor pressure vessel (RPV) steel of nuclear power plants. The combination of low Cu and high Ni used in some RPV welds is known to further enhance the DBTT shift during long time operation. In this study, RPV weld samples containing 0.04 at% Cu and 1.6 at% Ni were irradiated to 2.0 and 6.4×1023 n/m2 in the Halden test reactor. Atom probe tomography (APT) was applied to study clustering of Ni, Mn, Si, and Cu. As the clusters are in the nanometer-range, APT is a very suitable technique for this type of study. From APT analyses information about size distribution, number density, and composition of the clusters can be obtained. However, the quantification of these attributes is not trivial. The maximum separation method (MSM) has been used to characterize the clusters and a detailed study about the influence of the choice of MSM cluster parameters, primarily on the cluster number density, has been undertaken.

Nonlinear Burn Control in Tokamaks using Heating, Non-axisymmetric Magnetic Fields, Isotopic fueling and Impurity injection

NASA Astrophysics Data System (ADS)

Pajares, Andres; Schuster, Eugenio

2016-10-01

Plasma density and temperature regulation in future tokamaks such as ITER is arising as one of the main problems in nuclear-fusion control research. The problem, known as burn control, is to regulate the amount of fusion power produced by the burning plasma while avoiding thermal instabilities. Prior work in the area of burn control considered different actuators, such as modulation of the auxiliary power, modulation of the fueling rate, and controlled impurity injection. More recently, the in-vessel coil system was suggested as a feasible actuator since it has the capability of modifying the plasma confinement by generating non-axisymmetric magnetic fields. In this work, a comprehensive, model-based, nonlinear burn control strategy is proposed to integrate all the previously mentioned actuators. A model to take into account the influence of the in-vessel coils on the plasma confinement is proposed based on the plasma collisionality and the density. A simulation study is carried out to show the capability of the controller to drive the system between different operating points while rejecting perturbations. Supported by the US DOE under DE-SC0010661.

The challenge of tree height in Eucalyptus regnans: when xylem tapering overcomes hydraulic resistance.

PubMed

Petit, Giai; Pfautsch, Sebastian; Anfodillo, Tommaso; Adams, Mark A

2010-09-01

*Recent research suggests that increasing conduit tapering progressively reduces hydraulic constraints caused by tree height. Here, we tested this hypothesis using the tallest hardwood species, Eucalyptus regnans. *Vertical profiles of conduit dimensions and vessel density were measured for three mature trees of height 47, 51 and 63 m. *Mean hydraulic diameter (Dh) increased rapidly from the tree apex to the point of crown insertion, with the greatest degree of tapering yet reported (b > 0.33). Conduit tapering was such that most of the total resistance was found close to the apex (82-93% within the first 1 m of stem) and the path length effect was reduced by a factor of 2000. Vessel density (VD) declined from the apex to the base of each tree, with scaling parameters being similar for all trees (a = 4.6; b = -0.5). *Eucalyptus regnans has evolved a novel xylem design that ensures a high hydraulic efficiency. This feature enables the species to grow quickly to heights of 50-60 m, beyond the maximum height of most other hardwood trees.

Optical Coherence Tomography Angiography Characteristics of Iris Melanocytic Tumors

PubMed Central

Skalet, Alison H.; Li, Yan; Lu, Chen D.; Jia, Yali; Lee, ByungKun; Husvogt, Lennart; Maier, Andreas; Fujimoto, James G.; Thomas, Charles R.; Huang, David

2016-01-01

Objective To evaluate tumor vasculature with optical coherence tomography (OCT) angiography (OCTA) in malignant iris melanomas and benign iris lesions. Design Cross-sectional observational clinical study. Participants Patients with iris lesions and healthy volunteers. Methods Eyes were imaged using OCTA systems operating at 1050 and 840 nm wavelengths. Three-dimensional OCTA scans were acquired. Iris melanomas patients treated with radiation therapy were imaged again after I-125 plaque brachytherapy at 6 and 18 months. Main Outcome Measures OCT and OCTA images, qualitative evaluation of iris and tumor vasculature and quantitative vessel density. Results One eye each of eight normal volunteers and nine patients with iris melanomas or benign iris lesions including freckles, nevi, and an iris pigment epithelial (IPE) cyst were imaged. The normal iris has radially-oriented vessels within the stroma on OCTA. Penetration of flow signal in normal iris depended on iris color, with best penetration seen in light to moderately pigmented irides. Iris melanomas demonstrated tortuous and disorganized intratumoral vasculature. In two eyes with nevi there was no increased vascularity; in another, fine vascular loops were noted near an area of ectropion uveae. Iris freckles and the IPE cyst did not have intrinsic vascularity. The vessel density was significantly higher within iris melanomas (34.5%±9.8%, p<0.05) than in benign iris nevi (8.0%±1.4%) or normal irides (8.0%±1.2%). Tumor regression after radiation therapy for melanomas was associated with decreased vessel density. OCTA at 1050 nm provided better visualization of tumor vasculature and penetration through thicker tumors than at 840 nm. But in very thick tumors and highly pigmented lesions even 1050 nm OCTA could not visualize their full thickness. Interpretable OCTA images were obtained in 82% participants in whom imaging was attempted. Conclusions This is the first demonstration of OCTA in iris tumors. OCTA may provide a dye-free, no-injection, cost-effective method for monitoring a variety of tumors including iris melanocytic lesions for growth and vascularity. This could be helpful in evaluating tumors for malignant transformation and response to treatment. Penetration of the OCT beam remains a limitation for highly pigmented tumors, as does the inability to image the entire iris in a single field. PMID:27856029