An immunohistochemical screening of neurochemical markers in fungiform papillae and taste buds of the anterior rat tongue.

PubMed

Astbäck, J; Arvidson, K; Johansson, O

1997-02-01

The occurrence and distribution of several neurochemical markers were investigated. Numerous nerve fibres were shown, using antibodies to protein gene product (PGP) 9.5, neurone-specific enolase, calcitonin gene-related peptide (CGRP), substance P. neurokinin A or protein S-100. The presence of vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine amide (PHI), neuropeptide tyrosine, dopamine-beta-hydroxylase (DBH), cholecystokinin/gastrin, glutamate and galanin was more scarce. Nerve fibres containing these above-mentioned markers were found at several locations, i.e. in the epithelium, connective tissue, and around blood vessels. In the taste buds, numerous PGP 9.5, neurone-specific enolase-, CGRP-, substance P-, neurokinin A- and protein S-100-containing structures were found, but few VIP and galanin ones. No immunoreactivity was found with antibodies against somatostatin, bombesin, enkephalin or dynorphin. These findings extend knowledge about the general as well as the neurochemical messenger-based innervation of rat fungiform papillae, forming a firm basis for future functional investigations of normal, experimental and also clinical materials.

Regulation of endothelium-derived vasoactive autacoid production by hemodynamic forces.

PubMed

Busse, Rudi; Fleming, Ingrid

2003-01-01

Endothelial cells, which are situated at the interface between blood and the vessel wall, have a crucial role in controlling vascular tone and homeostasis, particularly in determining the expression of pro-atherosclerotic and anti-atherosclerotic genes. Many of these effects are mediated by changes in the generation and release of endothelium-derived autacoids [from the Greek autos (self) and akos (remedy)], which are generally short-lived and locally acting. In vivo, endothelial cells are constantly subjected to mechanical stimulation, which in turn determines the acute production of autacoids and the levels of autacoid-producing enzymes.

Safety of peripheral intravenous administration of vasoactive medication.

PubMed

Cardenas-Garcia, Jose; Schaub, Karen F; Belchikov, Yuly G; Narasimhan, Mangala; Koenig, Seth J; Mayo, Paul H

2015-09-01

Central venous access is commonly performed to administer vasoactive medication. The administration of vasoactive medication via peripheral intravenous access is a potential method of reducing the need for central venous access. The aim of this study was to evaluate the safety of vasoactive medication administered through peripheral intravenous access. Over a 20-month period starting in September 2012, we monitored the use of vasoactive medication via peripheral intravenous access in an 18-bed medical intensive care unit. Norepinephrine, dopamine, and phenylephrine were all approved for use through peripheral intravenous access. A total of 734 patients (age 72 ± 15 years, male/female 398/336, SAPS II score 75 ± 15) received vasoactive medication via peripheral intravenous access 783 times. Vasoactive medication used was norepinephrine (n = 506), dopamine (n = 101), and phenylephrine (n = 176). The duration of vasoactive medication via peripheral intravenous access was 49 ± 22 hours. Extravasation of the peripheral intravenous access during administration of vasoactive medication occurred in 19 patients (2%) without any tissue injury following treatment, with local phentolamine injection and application of local nitroglycerin paste. There were 95 patients (13%) receiving vasoactive medication through peripheral intravenous access who eventually required central intravenous access. Administration of norepinephrine, dopamine, or phenylephrine by peripheral intravenous access was feasible and safe in this single-center medical intensive care unit. Extravasation from the peripheral intravenous line was uncommon, and phentolamine with nitroglycerin paste were effective in preventing local ischemic injury. Clinicians should not regard the use of vasoactive medication is an automatic indication for central venous access. © 2015 Society of Hospital Medicine.

Two ways to feel the pressure: an endothelial Ca(2+) entry channel with dual mechanosensitivity.

PubMed

Groschner, Klaus

2002-01-01

One impressive function of the vascular endothelium is its ability to adjust the release of vasoactive mediators such as NO and PGI(2) almost instantaneously to changes in blood flow or blood pressure. Besides this fast feedback response to hemodynamic alterations, the endothelium is subject to long-term adaptations that are crucial for prevention of pathological processes such as atherogenesis. Among the various signals that are sensed by endothelial cells, mechanical forces which arise from pulsatile blood flow are probably most important for fast as well as long-term control of blood vessel function by the endothelium.

Validation of the Vasoactive-Inotropic Score in Pediatric Sepsis.

PubMed

McIntosh, Amanda M; Tong, Suhong; Deakyne, Sara J; Davidson, Jesse A; Scott, Halden F

2017-08-01

To assess the validity of Vasoactive-Inotropic Score as a scoring system for cardiovascular support and surrogate outcome in pediatric sepsis. Secondary retrospective analysis of a single-center sepsis registry. Freestanding children's hospital and tertiary referral center. Children greater than 60 days and less than 18 years with sepsis identified in the emergency department between January 2012 and June 2015 treated with at least one vasoactive medication within 48 hours of admission to the PICU. None. Vasoactive-Inotropic Score was abstracted at 6, 12, 24, and 48 hours post ICU admission. Primary outcomes were ventilator days and ICU length of stay. The secondary outcome was a composite outcome of cardiac arrest/extracorporeal membrane oxygenation/in-hospital mortality. One hundred thirty-eight patients met inclusion criteria. Most common infectious sources were pneumonia (32%) and bacteremia (23%). Thirty-three percent were intubated and mortality was 6%. Of the time points assessed, Vasoactive-Inotropic Score at 48 hours showed the strongest correlation with ICU length of stay (r = 0.53; p < 0.0001) and ventilator days (r = 0.52; p < 0.0001). On multivariable analysis, Vasoactive-Inotropic Score at 48 hours was a strong independent predictor of primary outcomes and intubation. For every unit increase in Vasoactive-Inotropic Score at 48 hours, there was a 13% increase in ICU length of stay (p < 0.001) and 8% increase in ventilator days (p < 0.01). For every unit increase in Vasoactive-Inotropic Score at 12 hours, there was a 14% increase in odds of having the composite outcome (p < 0.01). Vasoactive-Inotropic Score in pediatric sepsis patients is independently associated with important clinically relevant outcomes including ICU length of stay, ventilator days, and cardiac arrest/extracorporeal membrane oxygenation/mortality. Vasoactive-Inotropic Score may be a useful surrogate outcome in pediatric sepsis.

Calcitonin gene-related peptide stimulates proliferation of human endothelial cells.

PubMed Central

Haegerstrand, A; Dalsgaard, C J; Jonzon, B; Larsson, O; Nilsson, J

1990-01-01

The effects of the vasoactive perivascular neuropeptides calcitonin gene-related peptide (CGRP), neurokinin A (NKA), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) on proliferation of cultured human umbilical vein endothelial cells (HUVECs) were investigated. CGRP was shown to increase both cell number and DNA synthesis, whereas NKA, NPY, and VIP were ineffective. 125I-labeled CGRP was shown to bind to HUVECs and this binding was displaced by addition of unlabeled CGRP, suggesting the existence of specific CGRP receptors. The effect of CGRP on formation of adenosine 3',5'-cyclic monophosphate (cAMP) and inositol phosphates (InsP), two intracellular messengers known to be involved in regulation of cell proliferation, was investigated. CGRP stimulated cAMP formation but was without effect on the formation of InsP. Proliferation, as well as cAMP formation, was also stimulated by cholera toxin. Basic fibroblast growth factor stimulated growth without affecting cAMP or InsP formation, whereas thrombin, which increased InsP formation, did not stimulate proliferation. We thus suggest that CGRP may act as a local factor stimulating proliferation of endothelial cells; that the mechanism of action is associated with cAMP formation; and that this effect of CGRP may be important for formation of new vessels during physiological and pathophysiological events such as ischemia, inflammation, and wound healing. PMID:2159144

Calcitonin gene-related peptide stimulates proliferation of human endothelial cells.

PubMed

Haegerstrand, A; Dalsgaard, C J; Jonzon, B; Larsson, O; Nilsson, J

1990-05-01

The effects of the vasoactive perivascular neuropeptides calcitonin gene-related peptide (CGRP), neurokinin A (NKA), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) on proliferation of cultured human umbilical vein endothelial cells (HUVECs) were investigated. CGRP was shown to increase both cell number and DNA synthesis, whereas NKA, NPY, and VIP were ineffective. 125I-labeled CGRP was shown to bind to HUVECs and this binding was displaced by addition of unlabeled CGRP, suggesting the existence of specific CGRP receptors. The effect of CGRP on formation of adenosine 3',5'-cyclic monophosphate (cAMP) and inositol phosphates (InsP), two intracellular messengers known to be involved in regulation of cell proliferation, was investigated. CGRP stimulated cAMP formation but was without effect on the formation of InsP. Proliferation, as well as cAMP formation, was also stimulated by cholera toxin. Basic fibroblast growth factor stimulated growth without affecting cAMP or InsP formation, whereas thrombin, which increased InsP formation, did not stimulate proliferation. We thus suggest that CGRP may act as a local factor stimulating proliferation of endothelial cells; that the mechanism of action is associated with cAMP formation; and that this effect of CGRP may be important for formation of new vessels during physiological and pathophysiological events such as ischemia, inflammation, and wound healing.

Validation of the Vasoactive-Inotropic Score in Pediatric Sepsis*

PubMed Central

Tong, Suhong; Deakyne, Sara J.; Davidson, Jesse A.; Scott, Halden F.

2017-01-01

Objectives: To assess the validity of Vasoactive-Inotropic Score as a scoring system for cardiovascular support and surrogate outcome in pediatric sepsis. Design: Secondary retrospective analysis of a single-center sepsis registry. Setting: Freestanding children’s hospital and tertiary referral center. Patients: Children greater than 60 days and less than 18 years with sepsis identified in the emergency department between January 2012 and June 2015 treated with at least one vasoactive medication within 48 hours of admission to the PICU. Interventions: None. Measurements and Main Results: Vasoactive-Inotropic Score was abstracted at 6, 12, 24, and 48 hours post ICU admission. Primary outcomes were ventilator days and ICU length of stay. The secondary outcome was a composite outcome of cardiac arrest/extracorporeal membrane oxygenation/in-hospital mortality. One hundred thirty-eight patients met inclusion criteria. Most common infectious sources were pneumonia (32%) and bacteremia (23%). Thirty-three percent were intubated and mortality was 6%. Of the time points assessed, Vasoactive-Inotropic Score at 48 hours showed the strongest correlation with ICU length of stay (r = 0.53; p < 0.0001) and ventilator days (r = 0.52; p < 0.0001). On multivariable analysis, Vasoactive-Inotropic Score at 48 hours was a strong independent predictor of primary outcomes and intubation. For every unit increase in Vasoactive-Inotropic Score at 48 hours, there was a 13% increase in ICU length of stay (p < 0.001) and 8% increase in ventilator days (p < 0.01). For every unit increase in Vasoactive-Inotropic Score at 12 hours, there was a 14% increase in odds of having the composite outcome (p < 0.01). Conclusions: Vasoactive-Inotropic Score in pediatric sepsis patients is independently associated with important clinically relevant outcomes including ICU length of stay, ventilator days, and cardiac arrest/extracorporeal membrane oxygenation/mortality. Vasoactive-Inotropic Score may be a useful surrogate outcome in pediatric sepsis. PMID:28486385

Learning to manage vasoactive drugs-A qualitative interview study with critical care nurses.

PubMed

Häggström, Marie; Bergsman, Ann-Christin; Månsson, Ulrika; Holmström, Malin Rising

2017-04-01

Being a nurse in an intensive care unit entails caring for seriously ill patients. Vasoactive drugs are one of the tools that are used to restore adequate circulation. Critical care nurses often manage and administer these potent drugs after medical advice from physicians. To describe the experiences of critical care nurses learning to manage vasoactive drugs, and to highlight the competence required to manage vasoactive drugs. Twelve critical care nurses from three hospitals in Sweden were interviewed. Qualitative content analysis was applied. The theme "becoming proficient requires accuracy, practice and precaution" illustrated how critical care nurses learn to manage vasoactive drugs. Learning included developing cognitive, psychomotor, and effective skills. Sources for knowledge refers to specialist education combined with practical exercises, collegial support, and accessible routine documents. The competence required to manage vasoactive drugs encompassed well-developed safety thinking that included being careful, in control, and communicating failures. Specific skills were required such as titrating doses, being able to analyse and evaluate the technological assessments, adapting to the situation, and staying calm. Learning to manage vasoactive drugs requires a supportive introduction for novices, collegial support, lifelong learning, and a culture of safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

Disruption of astrocyte-vascular coupling and the blood-brain barrier by invading glioma cells

PubMed Central

Watkins, Stacey; Robel, Stefanie; Kimbrough, Ian F.; Robert, Stephanie M.; Ellis-Davies, Graham; Sontheimer, Harald

2014-01-01

Astrocytic endfeet cover the entire cerebral vasculature and serve as exchange sites for ions, metabolites, and energy substrates from the blood to the brain. They maintain endothelial tight junctions that form the blood-brain barrier (BBB) and release vasoactive molecules that regulate vascular tone. Malignant gliomas are highly invasive tumors that use the perivascular space for invasion and co-opt existing vessels as satellite tumors form. Here we use a clinically relevant mouse model of glioma and find that glioma cells, as they populate the perivascular space of pre-existing vessels, displace astrocytic endfeet from endothelial or vascular smooth muscle cells. This causes a focal breach in the BBB. Furthermore, astrocyte-mediated gliovascular coupling is lost, and glioma cells seize control over regulation of vascular tone through Ca2+-dependent release of K+. These findings have important clinical implications regarding blood flow in the tumor-associated brain and the ability to locally deliver chemotherapeutic drugs in disease. PMID:24943270

Acrolein generation stimulates hypercontraction in isolated human blood vessels

PubMed Central

Conklin, D.J.; Bhatnagar, A.; Cowley, H.R.; Johnson, G.H.; Wiechmann, R.J.; Sayre, L.M.; Trent, M.B.; Boor, P.J.

2012-01-01

Increased risk of vasospasm, a spontaneous hyperconstriction, is associated with atherosclerosis, cigarette smoking, and hypertension—all conditions involving oxidative stress, lipid peroxidation, and inflammation. To test the role of the lipid peroxidation- and inflammation-derived aldehyde, acrolein, in human vasospasm, we developed an ex vivo model using human coronary artery bypass graft (CABG) blood vessels and a demonstrated acrolein precursor, allylamine. Allylamine induces hypercontraction in isolated rat coronary artery in a semicarbazide-sensitive amine oxidase activity (SSAO) dependent manner. Isolated human CABG blood vessels (internal mammary artery, radial artery, saphenous vein) were used to determine: (1) vessel responses and sensitivity to acrolein, allylamine, and H2O2 exposure (1 μM–1 mM), (2) SSAO dependence of allylamine-induced effects using SSAO inhibitors (semicarbazide, 1 mM; MDL 72274-E, active isomer; MDL 72274-Z, inactive isomer; 100 μM), (3) the vasoactive effects of two other SSAO amine substrates, benzylamine and methylamine, and (4) the contribution of extracellular Ca2+ to hypercontraction. Acrolein or allylamine but not H2O2, benzylamine, or methylamine stimulated spontaneous and pharmacologically intractable hypercontraction in CABG blood vessels that was similar to clinical vasospasm. Allylamine-induced hypercontraction and blood vessel SSAO activity were abolished by pretreatment with semicarbazide or MDL 72274-E but not by MDL 72274-Z. Allylamine-induced hypercontraction also was significantly attenuated in Ca2+-free buffer. In isolated aorta of spontaneously hypertensive rat, allylamine-induced an SSAO-dependent contraction and enhanced norepinephrine sensitivity but not in Sprague–Dawley rat aorta. We conclude that acrolein generation in the blood vessel wall increases human susceptibility to vasospasm, an event that is enhanced in hypertension. PMID:17095030

Effect of demedullation on freezing injury in hind limbs of rats

NASA Astrophysics Data System (ADS)

Dhingra, Shashi; Bhatia, B.; Chhina, G. S.; Singh, Baldev

1987-09-01

Freezing incidence and tissue loss on exposure of hind limbs of female Wistar rats to freezing mixture was reduced by demedullation 6 days prior to cold exposure (p<0.01 and p<0.001 respectively); demedullation 1 h after freezing injury had no effect on tissue loss. Noradrenaline (1 mg/kg i.p.) 5 min before exposure increased the freezing incidence in intact (p<0.05) as well as in demedullated rats (p<0.01), with no effect on tissue loss. Adrenaline (500 mg/kg i.p.) had no effect on either. A sustained fall in plasma adrenaline after demedullation leading to reduced reactivity of the blood vessels to some vasoactive agents is postulated.

Melanopsin mediates light-dependent relaxation in blood vessels.

PubMed

Sikka, Gautam; Hussmann, G Patrick; Pandey, Deepesh; Cao, Suyi; Hori, Daijiro; Park, Jong Taek; Steppan, Jochen; Kim, Jae Hyung; Barodka, Viachaslau; Myers, Allen C; Santhanam, Lakshmi; Nyhan, Daniel; Halushka, Marc K; Koehler, Raymond C; Snyder, Solomon H; Shimoda, Larissa A; Berkowitz, Dan E

2014-12-16

Melanopsin (opsin4; Opn4), a non-image-forming opsin, has been linked to a number of behavioral responses to light, including circadian photo-entrainment, light suppression of activity in nocturnal animals, and alertness in diurnal animals. We report a physiological role for Opn4 in regulating blood vessel function, particularly in the context of photorelaxation. Using PCR, we demonstrate that Opn4 (a classic G protein-coupled receptor) is expressed in blood vessels. Force-tension myography demonstrates that vessels from Opn4(-/-) mice fail to display photorelaxation, which is also inhibited by an Opn4-specific small-molecule inhibitor. The vasorelaxation is wavelength-specific, with a maximal response at ∼430-460 nm. Photorelaxation does not involve endothelial-, nitric oxide-, carbon monoxide-, or cytochrome p450-derived vasoactive prostanoid signaling but is associated with vascular hyperpolarization, as shown by intracellular membrane potential measurements. Signaling is both soluble guanylyl cyclase- and phosphodiesterase 6-dependent but protein kinase G-independent. β-Adrenergic receptor kinase 1 (βARK 1 or GRK2) mediates desensitization of photorelaxation, which is greatly reduced by GRK2 inhibitors. Blue light (455 nM) regulates tail artery vasoreactivity ex vivo and tail blood blood flow in vivo, supporting a potential physiological role for this signaling system. This endogenous opsin-mediated, light-activated molecular switch for vasorelaxation might be harnessed for therapy in diseases in which altered vasoreactivity is a significant pathophysiologic contributor.

pH-driven colloidal transformations based on the vasoactive drug nicergoline.

PubMed

Salentinig, Stefan; Tangso, Kristian J; Hawley, Adrian; Boyd, Ben J

2014-12-16

The structure of colloidal self-assembled drug delivery systems can be influenced by intermolecular interactions between drug and amphiphilic molecules, and is important to understand in the context of designing improved delivery systems. Controlling these structures can enable controlled or targeted release systems for poorly water-soluble drugs. Here we present the interaction of the hydrophobic vasoactive drug nicergoline with the internal structure of nanostructured emulsion particles based on the monoglyceride-water system. Addition of this drug leads to modification of the internal bicontinuous cubic structure to generate highly pH-responsive systems. The colloidal structures were characterized with small-angle X-ray scattering and visualized using cryogenic transmission electron microscopy. Reversible transformations to inverse micelles at high pH, vesicles at low pH, and the modification of the spacing of the bicontinuous cubic structure at intermediate pH were observed, and enabled the in situ determination of an apparent pKa for the drug in this system--a difficult task using solution-based approaches. The characterization of this phase behavior is also highly interesting for the design of pH-responsive controlled release systems for poorly water-soluble drug molecules.

Delivery of platinum(IV) drug to subcutaneous tumor and lung metastasis using bradykinin-potentiating peptide-decorated chitosan nanoparticles.

PubMed

Wang, Xin; Yang, Chenchen; Zhang, Yajun; Zhen, Xu; Wu, Wei; Jiang, Xiqun

2014-08-01

Selectively activating tumor vessels to increase drug delivery and reduce interstitial fluid pressure of tumors is actively pursued. Here we developed a vasoactive peptide-decorated chitosan nanoparticles for enhancing drug accumulation and penetration in subcutaneous tumor and lung metastasis. The vasoactive peptide used here is bradykinin-potentiating peptide (BPP) containing 9 amino acid residues and the drug is bioreductively sensitive platinum(IV) compound which becomes cisplatin in intracellular reductive environments. Both peptide and drug are covalently linked with chitosan nanoparticles with a diameter of 120 nm. We demonstrate that BPP-decorated chitosan nanoparticles increase the tumorous vascular permeability and reduce the interstitial fluid pressure of tumor simultaneously, both of which improve the penetration of nanoparticles in tumor tissues. The in vivo biodistribution and tumor inhibition examinations demonstrate that the BPP-decorated nanoparticle formulation has more superior efficacy in enhancing drug accumulation in tumor, restraining tumor growth and prolonging the lifetime of tumor-bearing mice than free drug and non-decorated nanoparticle formulation. Meanwhile, the drug accumulation in the lung with metastasis reaches 17% and 20% injected dose per gram of lung for the chitosan nanoparticles without and with BPP decoration, respectively, which is 10-fold larger than that of free cisplatin. The examination of lung metastasis inhibition further indicates that BPP-decorated chitosan nanoparticle formulations can more effectively inhibit lung metastasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Peptidergic innervation of the human male genital tract.

PubMed

Gu, J; Polak, J M; Probert, L; Islam, K N; Marangos, P J; Mina, S; Adrian, T E; McGregor, G P; O'Shaughnessy, D J; Bloom, S R

1983-08-01

Four peptides--vasoactive intestinal polypeptide, substance P, somatostatin and a peptide-like avian pancreatic polypeptide--have been found in nerves of the human male genitalia using highly sensitive and specific methods of immunocytochemistry and radioimmunoassay. Five other peptides (met-enkephalin, leu-enkephalin, neurotensin, bombesin and cholecystokinin-8) were absent. Vasoactive intestinal polypeptide was the most abundant peptide, its highest concentration being in the proximal corpus cavernosum. Immunoelectron microscopy localized this peptide to large (97 +/- 20 nm), round, electron-dense granules of p-type nerve terminals. Vasoactive intestinal polypeptide-immunoreactive neuronal cell bodies were found in the prostate gland and the root of the corpus cavernosum. Substance P immunoreactive material was present in smaller concentration and was mainly localized in nerves around the corpuscular receptors of the glans penis. Somatostatin immunoreactive nerves were associated mainly with the smooth muscle of the seminal vesicle and the vas deferens. When antiserum to avian pancreatic polypeptide was applied, certain nerves were stained, particularly in the vas deferens, the prostate gland and the seminal vesicle. However, chromatography detected no pure avian pancreatic polypeptide suggesting the presence of a structurally related substance, possibly neuropeptide Y, which cross-reacts with the avian pancreatic polypeptide antiserum. Similar distributions between vasoactive intestinal polypeptide-immunoreactive and acetylcholinesterase-positive nerves and between avian pancreatic polypeptide-immunoreactive and adrenergic nerves were observed. A general neuronal marker, neuron-specific enolase, was used to investigate the general pattern of the organ's innervation. The abundance and distribution patterns of these peptide-immunoreactive nerves indicate that they may play important roles in the male sexual physiology.

Constitutive nitric oxide synthase activation is a significant route for nitroglycerin-mediated vasodilation

PubMed Central

Bonini, Marcelo G.; Stadler, Krisztian; de Oliveira Silva, Sueli; Corbett, Jean; Dore, Michael; Petranka, John; Fernandes, Denise C.; Tanaka, Leonardo Y.; Duma, Danielle; Laurindo, Francisco R. M.; Mason, Ronald P.

2008-01-01

The physiological effects of nitroglycerin as a potent vasodilator have long been documented. However, the molecular mechanisms by which nitroglycerin exerts its biological functions are still a matter of intense debate. Enzymatic pathways converting nitroglycerin to vasoactive compounds have been identified, but none of them seems to fully account for the reported clinical observations. Here, we demonstrate that nitroglycerin triggers constitutive nitric oxide synthase (NOS) activation, which is a major source of NO responsible for low-dose (1–10 nM) nitroglycerin-induced vasorelaxation. Our studies in cell cultures, isolated vessels, and whole animals identified endothelial NOS activation as a fundamental requirement for nitroglycerin action at pharmacologically relevant concentrations in WT animals. PMID:18562300

Baroreflex buffering and susceptibility to vasoactive drugs

NASA Technical Reports Server (NTRS)

Jordan, Jens; Tank, Jens; Shannon, John R.; Diedrich, Andre; Lipp, Axel; Schroder, Christoph; Arnold, Guy; Sharma, Arya M.; Biaggioni, Italo; Robertson, David;

Melanopsin mediates light-dependent relaxation in blood vessels

PubMed Central

Sikka, Gautam; Hussmann, G. Patrick; Pandey, Deepesh; Cao, Suyi; Hori, Daijiro; Park, Jong Taek; Steppan, Jochen; Kim, Jae Hyung; Barodka, Viachaslau; Myers, Allen C.; Santhanam, Lakshmi; Nyhan, Daniel; Halushka, Marc K.; Koehler, Raymond C.; Snyder, Solomon H.; Shimoda, Larissa A.; Berkowitz, Dan E.

2014-01-01

Melanopsin (opsin4; Opn4), a non-image-forming opsin, has been linked to a number of behavioral responses to light, including circadian photo-entrainment, light suppression of activity in nocturnal animals, and alertness in diurnal animals. We report a physiological role for Opn4 in regulating blood vessel function, particularly in the context of photorelaxation. Using PCR, we demonstrate that Opn4 (a classic G protein-coupled receptor) is expressed in blood vessels. Force-tension myography demonstrates that vessels from Opn4−/− mice fail to display photorelaxation, which is also inhibited by an Opn4-specific small-molecule inhibitor. The vasorelaxation is wavelength-specific, with a maximal response at ∼430–460 nm. Photorelaxation does not involve endothelial-, nitric oxide-, carbon monoxide-, or cytochrome p450-derived vasoactive prostanoid signaling but is associated with vascular hyperpolarization, as shown by intracellular membrane potential measurements. Signaling is both soluble guanylyl cyclase- and phosphodiesterase 6-dependent but protein kinase G-independent. β-Adrenergic receptor kinase 1 (βARK 1 or GRK2) mediates desensitization of photorelaxation, which is greatly reduced by GRK2 inhibitors. Blue light (455 nM) regulates tail artery vasoreactivity ex vivo and tail blood blood flow in vivo, supporting a potential physiological role for this signaling system. This endogenous opsin-mediated, light-activated molecular switch for vasorelaxation might be harnessed for therapy in diseases in which altered vasoreactivity is a significant pathophysiologic contributor. PMID:25404319

Effect of Flow on Gene Regulation in Smooth Muscle Cells and Macromolecular Transport Across Endothelial Cell Monolayers

NASA Technical Reports Server (NTRS)

McIntire, Larry V.; Wagner, John E.; Papadaki, Maria; Whitson, Peggy A.; Eskin, Suzanne G.

1996-01-01

Endothelial cells line all of the vessels of the circulatory system, providing a non-thrombogenic conduit for blood flow; they regulate many complex functions in the vasculature, such as coagulation, fibrinolysis, platelet aggregation, vessel tone and growth, and leukocyte traffic; and they form the principal barrier to transport of substances between the blood and the surrounding tissue space. The permeability of endothelial cell changes with environmental stimuli; shear stress, in particular, applied either in vivo, or in vitro, induces changes in protein expression and secretion of vasoactive factors by endothelial cells. The ability to study the effects of shear on the macromolecular permeability of the cerebral vasculature is particularly important, since in no other place is the barrier function of the endothelium more important than in the brain. The endothelial cells of this organ have developed special barrier properties that keep the cerebral system from experiencing any drastic change in composition; together with glial cells, they form the blood brain barrier (BBB). We have studied the effect of flow on bovine BBB using flow chambers and tissue culture systems.

Change of optical properties of the breast tissues under the influence of pharmacological agents

NASA Astrophysics Data System (ADS)

Naumov, Sergey A.; Vovk, Sergey M.; Pushkarev, Sergey V.; Volovodenko, Vitaly A.

2001-05-01

The influence of vasoactive pharmacological agents (VPhA) on the spectral characteristics of the breast tissues in vivo has been studied. The effect of adrenaline and its antagonist dibazole on the character of diffuse reflection spectra of the breast registered during puncture biopsy were investigated. Adrenaline and dibazole were injected both locally, i.e. to the examined breast tissue and subcutaneously to the shoulder. The choice of this or that VPhA was caused by the functional condition of an examinee. It has been shown that the main functional units of the stroma of parenchymatous organs and their tumors responsible for the state of spectral characteristics in vivo are considered to be the vessels. The cancerous tissue has a lesser pronounced response compared to the normal one that is indicative of the functional inferiority of the tumor vessels and it is confirmed by the results of morphological examinations including the ultrastructural level. Thus, using VPhA it is possible to have an influence on characteristics of diffuse reflection spectra of the examined tissues in vivo and make diagnostics more effectively.

X-ray intravital microscopy for functional imaging in rat hearts using synchrotron radiation coronary microangiography

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

Umetani, K.; Fukushima, K.

2013-03-15

An X-ray intravital microscopy technique was developed to enable in vivo visualization of the coronary, cerebral, and pulmonary arteries in rats without exposure of organs and with spatial resolution in the micrometer range and temporal resolution in the millisecond range. We have refined the system continually in terms of the spatial resolution and exposure time. X-rays transmitted through an object are detected by an X-ray direct-conversion type detector, which incorporates an X-ray SATICON pickup tube. The spatial resolution has been improved to 6 {mu}m, yielding sharp images of small arteries. The exposure time has been shortened to around 2 msmore » using a new rotating-disk X-ray shutter, enabling imaging of beating rat hearts. Quantitative evaluations of the X-ray intravital microscopy technique were extracted from measurements of the smallest-detectable vessel size and detection of the vessel function. The smallest-diameter vessel viewed for measurements is determined primarily by the concentration of iodinated contrast material. The iodine concentration depends on the injection technique. We used ex vivo rat hearts under Langendorff perfusion for accurate evaluation. After the contrast agent is injected into the origin of the aorta in an isolated perfused rat heart, the contrast agent is delivered directly into the coronary arteries with minimum dilution. The vascular internal diameter response of coronary arterial circulation is analyzed to evaluate the vessel function. Small blood vessels of more than about 50 {mu}m diameters were visualized clearly at heart rates of around 300 beats/min. Vasodilation compared to the control was observed quantitatively using drug manipulation. Furthermore, the apparent increase in the number of small vessels with diameters of less than about 50 {mu}m was observed after the vasoactive agents increased the diameters of invisible small blood vessels to visible sizes. This technique is expected to offer the potential for direct investigation of mechanisms of vascular dysfunctions.« less

Neurochemical markers of human fungiform papillae and taste buds.

PubMed

Astbäck, J; Arvidson, K; Johansson, O

1995-11-10

The presence of distribution of several neurochemical markers in human fungiform papillae and taste buds were investigated by the immunohistochemical technique. The gustatory cells of the taste buds are in synaptic contact with sensory nerve endings, and considering the taste buds strictly as specialized sensory organs, the amounts and distribution of some of the neurochemical markers were different to what we expected. For example, few structures showed immunoreactivity to the tachykinins substance P (SP), calcitonin gene-related peptide (CGRP), and neurokinin A (NKA) also for the peptides vasoactive intestinal polypeptide (VIP), neuropeptide tyrosine (NPY) and galanin, low amounts of immunoreactivity occurred. On the other hand, using antibodies to protein gene product 9.5 (PGP 9.5), protein S-100, and glutamate, numerous nerve fibres and/or immunoreactive cells were found in the fungiform papillae, in the epithelium, in the connective tissue and around blood vessels, as well as in or near taste buds. Incubation with the antibodies against somatostatin, enkephalin, bombesin, peptide histidine isoleucine amide (PHI), cholecystokinin (CCK)/gastrin and dopamine-beta-hydroxylase (DBH) was negative for the fungiform papillae. In conclusion, the present study has shown several immunoreactive structures using antibodies against certain neurochemical markers. Further investigations will hopefully correlate these morphological findings with functional taste perception data. Future studies of patients with taste disorders or other pathological changes correlated with taste and tongue will also be of utmost importance.

The Impact of Microgravity and Hypergravity on Endothelial Cells

PubMed Central

Maier, Jeanette A. M.

2015-01-01

The endothelial cells (ECs), which line the inner surface of vessels, play a fundamental role in maintaining vascular integrity and tissue homeostasis, since they regulate local blood flow and other physiological processes. ECs are highly sensitive to mechanical stress, including hypergravity and microgravity. Indeed, they undergo morphological and functional changes in response to alterations of gravity. In particular microgravity leads to changes in the production and expression of vasoactive and inflammatory mediators and adhesion molecules, which mainly result from changes in the remodelling of the cytoskeleton and the distribution of caveolae. These molecular modifications finely control cell survival, proliferation, apoptosis, migration, and angiogenesis. This review summarizes the state of the art on how microgravity and hypergravity affect cultured ECs functions and discusses some controversial issues reported in the literature. PMID:25654101

The impact of microgravity and hypergravity on endothelial cells.

PubMed

Maier, Jeanette A M; Cialdai, Francesca; Monici, Monica; Morbidelli, Lucia

2015-01-01

The endothelial cells (ECs), which line the inner surface of vessels, play a fundamental role in maintaining vascular integrity and tissue homeostasis, since they regulate local blood flow and other physiological processes. ECs are highly sensitive to mechanical stress, including hypergravity and microgravity. Indeed, they undergo morphological and functional changes in response to alterations of gravity. In particular microgravity leads to changes in the production and expression of vasoactive and inflammatory mediators and adhesion molecules, which mainly result from changes in the remodelling of the cytoskeleton and the distribution of caveolae. These molecular modifications finely control cell survival, proliferation, apoptosis, migration, and angiogenesis. This review summarizes the state of the art on how microgravity and hypergravity affect cultured ECs functions and discusses some controversial issues reported in the literature.

Localisation of the neuropeptide PACAP and its receptors in the rat parathyroid and thyroid glands.

PubMed

Fahrenkrug, Jan; Hannibal, Jens

2011-03-01

PACAP (pituitary adenylate cyclase activating polypeptide) is widely distributed neuropeptide acting via three subtypes of receptors, PAC(1), VPAC(1) and VPAC(2). Here we examined the localisation and nature of PACAP-immunoreactive nerves in the rat thyroid and parathyroid glands and defined the distribution of PAC(1), VPAC(1) and VPAC(2) receptor mRNA's. In the parathyroid gland a large number of nerve fibres displaying PACAP-immunoreactivity were distributed beneath the capsule, around blood vessels and close to glandular cells. Most of the PACAP-nerves were sensory, since they co-stored CGRP (calcitonin-gene-related peptide) and were sensitive to capsaicin-treatment. mRNA's for PAC(1) and VPAC(2) receptors occurred in the parathyroid gland, mainly located in the glandular cells. In the thyroid gland PACAP-immunoreactive nerve fibres were associated with blood vessels, thyroid follicles and parafollicular C-cells. A high degree of co-existence between PACAP and VIP (vasoactive intestinal polypeptide) was observed in the intrathyroid nerve fibres and cell bodies of the thyroid ganglion indicating a common origin for the two peptides. A minor population of PACAP-immunoreactive nerve fibres with relation to blood vessels co-stored NPY (neuropeptide Y), whereas only a few fibres co-stored CGRP. PAC(1) and VPAC(1) receptor mRNA's occurred in follicular cells and blood vessels, whereas the expression of the VPAC(2) receptor was low. The findings suggest that PACAP plays a role in the regulation of parathyroid and thyroid blood flow and hormone secretion. Copyright © 2010 Elsevier Inc. All rights reserved.

Modification of the rat aortic wall during ageing; possible relation with decrease of peptidergic innervation.

PubMed

Connat, J L; Busseuil, D; Gambert, S; Ody, M; Tébaldini, M; Gamboni, S; Faivre, B; Quiquerez, A L; Millet, M; Michaut, P; Rochette, L

2001-12-01

Structural changes of the male rat aorta were followed from birth to old age in male and female rats. In males, the vessel media width and area progressively increase concomitantly with a decrease of nuclei density during ageing, suggesting an hypertrophy of the smooth muscle cells. These correlations were however not evidenced in females. TUNEL-positive cells were found in media of 4 and 6 months in both sexes, mainly on the luminal side and in the adventitia. When biochemical markers were investigated with immunohistochemistry, media was uniformly stained by the anti-vimentin and anti-alpha-smooth actin at all stages investigated. On the contrary, the surface of media stained with anti-desmin decreased during ageing, especially on the luminal side. As observed with electron microscopy, with ageing the endothelium is replaced by small cells with pseudopodia adhering to the vestigial elastic lamina and infiltrating into the extracellular matrix left after the disappearance of smooth muscle cells. In addition, in the older rats (25-29 months) the elastic laminae are completely disorganised. Hypertrophy of the smooth muscle cells was confirmed by this approach. In parallel to this study, perivascular peptidergic innervation was stained with antibodies against calcitonin gene-related peptide (CGRP), substance P (SP), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) at different ages during the whole life of rats. These peptides are present in stages younger than 6 months, then gradually disappear. In one year animals and older, the peptidergic innervation has totally disappeared. We discuss the possible role of peptidergic innervation in the control of the vessel wall cellular stability during ageing.

The CGTCA sequence motif is essential for biological activity of the vasoactive intestinal peptide gene cAMP-regulated enhancer.

PubMed Central

Fink, J S; Verhave, M; Kasper, S; Tsukada, T; Mandel, G; Goodman, R H

1988-01-01

cAMP-regulated transcription of the human vasoactive intestinal peptide gene is dependent upon a 17-base-pair DNA element located 70 base pairs upstream from the transcriptional initiation site. This element is similar to sequences in other genes known to be regulated by cAMP and to sequences in several viral enhancers. We have demonstrated that the vasoactive intestinal peptide regulatory element is an enhancer that depends upon the integrity of two CGTCA sequence motifs for biological activity. Mutations in either of the CGTCA motifs diminish the ability of the element to respond to cAMP. Enhancers containing the CGTCA motif from the somatostatin and adenovirus genes compete for binding of nuclear proteins from C6 glioma and PC12 cells to the vasoactive intestinal peptide enhancer, suggesting that CGTCA-containing enhancers interact with similar transacting factors. Images PMID:2842787

Gene regulation by mechanical forces

NASA Technical Reports Server (NTRS)

Oluwole, B. O.; Du, W.; Mills, I.; Sumpio, B. E.

1997-01-01

Endothelial cells are subjected to various mechanical forces in vivo from the flow of blood across the luminal surface of the blood vessel. The purpose of this review was to examine the data available on how these mechanical forces, in particular cyclic strain, affect the expression and regulation of endothelial cell function. Studies from various investigators using models of cyclic strain in vitro have shown that various vasoactive mediators such as nitric oxide and prostacyclin are induced by the effect of mechanical deformation, and that the expression of these mediators may be regulated at the transcription level by mechanical forces. There also seems to be emerging evidence that endothelial cells may also act as mechanotransducers, whereby the transmission of external forces induces various cytoskeletal changes and second messenger cascades. Furthermore, it seems these forces may act on specific response elements of promoter genes.

Inhibitors of peptidases: how they influence the biological activities of substance P, neurokinins, kinins and angiotensins in isolated vessels.

PubMed

Rouissi, N; Nantel, F; Drapeau, G; Rhaleb, N E; Dion, S; Regoli, D

1990-01-01

Myotropic effects of various peptides were measured in three isolated vessels, the dog carotid artery, the rabbit pulmonary artery and the rat portal vein in the absence and in presence of several peptidase inhibitors, in order to evaluate the interference by metabolism with the peptides' biological activities. After adequate controls, captopril (4.6 x 10(-6) mol/l), thiorphan (1.0 x 10(-6) mol/l), phosphoramidon (4.6 x 10(-6) mol/l), chymostatin (1 mg/l), bestatin (8.1 x 10(-6) mol/l) or bacitracin (1.4 x 10(-5) mol/l) were left in contact with the tissues for 20-40 min to inhibit tissue peptidases before measuring again the biological effects of the various peptides. In some experiments, mergetpa (5.4 x 10(-6) mol/l) was used. All peptidase inhibitors were inactive on their own and only captopril potentiated the effects of substance P, neurokinins, bradykinin and inhibited angiotensin I in two preparations, the dog carotid artery, the rat portal vein, and, excluding bradykinin, also in the rabbit pulmonary artery. Captopril and thiorphan significantly potentiated the maximal response of the rat portal vein to substance P and mergetpa inhibited completely the effect of bradykinin on the rabbit pulmonary artery. The present findings suggest that the most active proteolytic enzyme interfering with the biological effects of vasoactive peptides on three isolated vessels is the angiotensin-converting enzyme (kininase II).

Vasoactivity of rucaparib, a PARP-1 inhibitor, is a complex process that involves myosin light chain kinase, P2 receptors, and PARP itself.

PubMed

McCrudden, Cian M; O'Rourke, Martin G; Cherry, Kim E; Yuen, Hiu-Fung; O'Rourke, Declan; Babur, Muhammad; Telfer, Brian A; Thomas, Huw D; Keane, Patrick; Nambirajan, Thiagarajan; Hagan, Chris; O'Sullivan, Joe M; Shaw, Chris; Williams, Kaye J; Curtin, Nicola J; Hirst, David G; Robson, Tracy

2015-01-01

Therapeutic inhibition of poly(ADP-ribose) polymerase (PARP), as monotherapy or to supplement the potencies of other agents, is a promising strategy in cancer treatment. We previously reported that the first PARP inhibitor to enter clinical trial, rucaparib (AG014699), induced vasodilation in vivo in xenografts, potentiating response to temozolomide. We now report that rucaparib inhibits the activity of the muscle contraction mediator myosin light chain kinase (MLCK) 10-fold more potently than its commercially available inhibitor ML-9. Moreover, rucaparib produces additive relaxation above the maximal degree achievable with ML-9, suggesting that MLCK inhibition is not solely responsible for dilation. Inhibition of nitric oxide synthesis using L-NMMA also failed to impact rucaparib's activity. Rucaparib contains the nicotinamide pharmacophore, suggesting it may inhibit other NAD+-dependent processes. NAD+ exerts P2 purinergic receptor-dependent inhibition of smooth muscle contraction. Indiscriminate blockade of the P2 purinergic receptors with suramin abrogated rucaparib-induced vasodilation in rat arterial tissue without affecting ML-9-evoked dilation, although the specific receptor subtypes responsible have not been unequivocally identified. Furthermore, dorsal window chamber and real time tumor vessel perfusion analyses in PARP-1-/- mice indicate a potential role for PARP in dilation of tumor-recruited vessels. Finally, rucaparib provoked relaxation in 70% of patient-derived tumor-associated vessels. These data provide tantalising evidence of the complexity of the mechanism underlying rucaparib-mediated vasodilation.

Substance-specific importance of EGFR for vascular smooth muscle cells motility in primary culture.

PubMed

Schreier, Barbara; Schwerdt, Gerald; Heise, Christian; Bethmann, Daniel; Rabe, Sindy; Mildenberger, Sigrid; Gekle, Michael

2016-07-01

Besides their importance for the vascular tone, vascular smooth muscle cells (VSMC) also contribute to pathophysiological vessel alterations. Various G-protein coupled receptor ligands involved in vascular dysfunction and remodeling can transactivate the epidermal growth factor receptor (EGFR) of VSMC, yet the importance of EGFR transactivation for the VSMC phenotype is incompletely understood. The aims of this study were (i) to characterize further the importance of the VSMC-EGFR for proliferation, migration and marker gene expression for inflammation, fibrosis and reactive oxygen species (ROS) homeostasis and (ii) to test the hypothesis that vasoactive substances (endothelin-1, phenylephrine, thrombin, vasopressin and ATP) rely differentially on the EGFR with respect to the abovementioned phenotypic alterations. In primary, aortic VSMC from mice without conditional deletion of the EGFR, proliferation, migration, marker gene expression (inflammation, fibrosis and ROS homeostasis) and cell signaling (ERK 1/2, intracellular calcium) were analyzed. VSMC-EGFR loss reduced collective cell migration and single cell migration probability, while no difference between the genotypes in single cell velocity, chemotaxis or marker gene expression could be observed under control conditions. EGF promoted proliferation, collective cell migration, chemokinesis and chemotaxis and leads to a proinflammatory gene expression profile in wildtype but not in knockout VSMC. Comparing the impact of five vasoactive substances (all reported to transactivate EGFR and all leading to an EGFR dependent increase in ERK1/2 phosphorylation), we demonstrate that the importance of EGFR for their action is substance-dependent and most apparent for crowd migration but plays a minor role for gene expression regulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Innervation pattern of the preocular human central retinal artery.

PubMed

Bergua, Antonio; Kapsreiter, Markus; Neuhuber, Winfried L; Reitsamer, Herbert A; Schrödl, Falk

2013-05-01

The central retinal artery (CRA) is the main vessel for inner retinal oxygen and nutrition supply. While the intraocular branches lack autonomic innervation, the innervation pattern of the extra-ocular part of this vessel along its course within the optic nerve is poorly investigated. This part however is essential for maintenance of retinal blood supply, in physiological and pathological conditions. Therefore, the aim of this study was the characterization of the autonomic innervation of the preocular CRA in humans with morphological methods. Meeting the Declaration of Helsinki, eyes of body or cornea donors were processed for single or double immunohistochemistry against tyrosine hydroxilase (TH), dopamine-β-hydroxylase (DBH), choline acetyl-transferase (ChAT), vesicular acetylcholine transporter (VAChT), neuronal nitric oxide synthase (nNOS), calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP), and cytochemistry for NADPH-diaphorase (NADPH-d). For documentation, light-, fluorescence-, and confocal laser-scanning microscopy were used. TH and DBH immunoreactive nerve fibres were detected in the CRA vessel wall, although a distinct perivascular plexus was missing. Further, nerve fibres immunoreactive for ChAT and VAChT were found, while CGRP, SP, and VIP were not detected. NADPH-d staining revealed scattered nerve fibres in the adventitia of the CRA and in close vicinity; however, nNOS-immunostaining could not confirm this finding. The CRA receives adrenergic and cholinergic innervations, indicating sympathetic and parasympathetic components, respectively. Remarkably, a peptidergic primary afferent innervation was missing. Since clinical results suggest an autoregulation of intraretinal vessels, further studies are needed to clarify the impact of CRA innervation for retinal perfusion. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vasoactive intestinal polypeptide microinjections into the oral pontine tegmentum enhance rapid eye movement sleep in the rat.

PubMed

Bourgin, P; Lebrand, C; Escourrou, P; Gaultier, C; Franc, B; Hamon, M; Adrien, J

1997-03-01

Rapid eye movement sleep can be elicited in the rat by microinjection of the cholinergic agonist carbachol into the oral pontine reticular nucleus. Intracerebroventricular administration, during the light period, of vasoactive intestinal peptide enhances rapid eye movement sleep in several species. Since this peptide is co-localized with acetylcholine in many neurons in the central nervous system, it was assumed that the oral pontine tegmentum could also be one target for vasoactive intestinal peptide to induce rapid eye movement sleep. This hypothesis was tested by recording the sleep-wakefulness cycle in freely-moving rats injected with vasoactive intestinal peptide or its fragments (1-12 and 10-28) directly into the oral pontine reticular nucleus. when administered into the posterior part of this nucleus, vasoactive intestinal peptide at 1 and 10 ng (in 0.1 microliter of saline), but not its fragments, induced a 2-fold enhancement of rapid eye movement sleep during 4 h, at the expense of wakefulness. At the dose of 10 ng, a significant increase in rapid eye movement sleep persisted for up to 8 h. Moreover, when the peptide was injected into the centre of the positive zone, rapid eye movement sleep was enhanced during three to eight consecutive days. These data provide the first evidence that rapid eye movement sleep can be elicited at both short- and long-term by a single intracerebral microinjection of vasoactive intestinal peptide. Peptidergic mechanisms, possibly in association with cholinergic mechanisms, within the caudal part of the oral pontine reticular nucleus may play a critical role in the long-term regulation of rapid eye movement sleep in rats.

Vasoactive intestinal peptide stimulates tracheal submucosal gland secretion in ferret

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

Peatfield, A.C.; Barnes, P.J.; Bratcher, C.

1983-07-01

We studied the effect of vasoactive intestinal peptide (VIP) on the output of 35S-labeled macromolecules from ferret tracheal explants either placed in beakers or suspended in modified Ussing chambers. In Ussing chamber experiments, the radiolabel precursor, sodium (35S)sulfate, and all drugs were placed on the submucosal side of the tissue. Washings were collected at 30-min intervals from the luminal side and were dialyzed to remove unbound 35S, leaving radiolabeled macromolecules. Vasoactive intestinal peptide at 3 X 10(-7) M stimulated bound 35S output by a mean of + 252.6% (n . 14). The VIP response was dose-dependent with a near maximalmore » response and a half maximal response at approximately 10(-6) M and 10(-8), M, respectively. The VIP effect was not inhibited by a mixture of tetrodotoxin, atropine, I-propranolol, and phentolamine. Vasoactive intestinal peptide had no effect on the electrical properties of the of the tissues. We conclude that VIP stimulates output of sulfated-macromolecules from ferret tracheal submucosal glands without stimulating ion transport. Our studies also suggest that VIP acts on submucosal glands via specific VIP receptors. Vasoactive intestinal peptide has been shown to increase intracellular levels of cyclic AMP, and we suggest that this may be the mechanism for its effect on the output of macromolecules. This mechanism may be important in the neural regulation of submucosal gland secretion.« less

Pancreatic neuroendocrine neoplasms: a current summary of diagnostic, prognostic, and differential diagnostic information.

PubMed

Wick, M R; Graeme-Cook, F M

2001-06-01

Pancreatic endocrine tumors (PETs) continue to be challenging diagnostic and prognostic lesions in surgical pathology and clinical medicine. These neoplasms can be graded into 1 of 3 tiers, based on histologic characteristics in likeness to epithelial neuroendocrine tumors in other anatomic sites. However, grade 1 tumors are by far the most common and are the most difficult to prognosticate. The most helpful features by which to gauge the behavior of such lesions include size (3 cm or larger); mitotic activity (2 or more mitoses per 10 high-power [x400] microscopic fields); marked nuclear atypia, especially with atypical mitoticfigures; predominant tumor synthesis of gastrin, vasoactive intestinal polypeptide, somatostatin, glucagon, calcitonin, or adrenocorticotropic hormone; complete nonfunctionality of the tumor at an immunohistochemical level; or invasion of blood vessels, nerves, or adjacent organs by the neoplasm. Differential diagnosis of PETs includes lesions such as solid-pseudopapillary neoplasms, acinar carcinomas, metastatic neuroendocrine tumors, and plasmacytomas.

Neural control of renal function: cardiovascular implications.

PubMed

DiBona, G F

1989-06-01

The innervation of the kidney serves to function of its component parts, for example, the blood vessels, the nephron (glomerulus, tubule), and the juxtaglomerular apparatus. Alterations in efferent renal sympathetic nerve activity produce significant changes in renal blood flow, glomerular filtration rate, the reabsorption of water, sodium, and other ions, and the release of renin, prostaglandins, and other vasoactive substances. These functional effects contribute significantly to the renal regulation of total body sodium and fluid volumes with important implications for the control of arterial pressure. The renal nerves, both efferent and afferent, are known to be important contributors to the pathogenesis of hypertension. In addition, the efferent renal nerves participate in the mediation of the excessive renal sodium retention, which characterizes edema-forming states such as congestive heart failure. Thus, the renal nerves play an important role in overall cardiovascular homeostasis in both normal and pathological conditions.

[Blood oxygen transport, prooxidant -- antioxidant status, and vasoactive characteristics of vascular endothelium in rats treated with endotoxin and taurine].

PubMed

Milosh, T S; Maksimovich, N E

2014-01-01

Experiments on a group of 74 pregnant rats upon intramuscular introduction of E. coli lipopolysaccharides during pregnancy revealed the correction effect of taurine on the blood oxygen transport function, prooxidant - antioxidant status, and vasoactive characteristics of vascular endothelium.

Effects of PPARγ Agonist Pioglitazone on Redox-Sensitive Cellular Signaling in Young Spontaneously Hypertensive Rats

PubMed Central

Dovinová, Ima; Barancik, Miroslav; Zorad, Stefan; Gajdosechová, Lucia; Gresová, Linda; Cacanyiova, Sona; Kristek, Frantisek; Balis, Peter; Chan, Julie Y. H.

2013-01-01

PPARγ receptor plays an important role in oxidative stress response. Its agonists can influence vascular contractility in experimental hypertension. Our study was focused on the effects of a PPARγ agonist pioglitazone (PIO) on blood pressure regulation, vasoactivity of vessels, and redox-sensitive signaling at the central (brainstem, BS) and peripheral (left ventricle, LV) levels in young prehypertensive rats. 5-week-old SHR were treated either with PIO (10 mg/kg/day, 2 weeks) or with saline using gastric gavage. Administration of PIO significantly slowed down blood pressure increase and improved lipid profile and aortic relaxation after insulin stimulation. A significant increase in PPARγ expression was found only in BS, not in LV. PIO treatment did not influence NOS changes, but had tissue-dependent effect on SOD regulation and increased SOD activity, observed in LV. The treatment with PIO differentially affected also the levels of other intracellular signaling components: Akt kinase increased in the the BS, while β-catenin level was down-regulated in the BS and up-regulated in the LV. We found that the lowering of blood pressure in young SHR can be connected with insulin sensitivity of vessels and that β-catenin and SOD levels are important agents mediating PIO effects in the BS and LV. PMID:24454335

In-vivo Fourier domain optical coherence tomography as a new tool for investigation of vasodynamics in the mouse model.

PubMed

Meissner, Sven; Müller, Gregor; Walther, Julia; Morawietz, Henning; Koch, Edmund

2009-01-01

In-vivo imaging of the vascular system can provide novel insight into the dynamics of vasoconstriction and vasodilation. Fourier domain optical coherence tomography (FD-OCT) is an optical, noncontact imaging technique based on interferometry of short-coherent near-infrared light with axial resolution of less than 10 microm. In this study, we apply FD-OCT as an in-vivo imaging technique to investigate blood vessels in their anatomical context using temporally resolved image stacks. Our chosen model system is the murine saphenous artery and vein, due to their small inner vessel diameters, sensitive response to vasoactive stimuli, and advantageous anatomical position. The vascular function of male wild-type mice (C57BL/6) is determined at the ages of 6 and 20 weeks. Vasoconstriction is analyzed in response to dermal application of potassium (K(+)), and vasodilation in response to sodium nitroprusside (SNP). Vasodynamics are quantified from time series (75 sec, 4 frames per sec, 330 x 512 pixels per frame) of cross sectional images that are analyzed by semiautomated image processing software. The morphology of the saphenous artery and vein is determined by 3-D image stacks of 512 x 512 x 512 pixels. Using the FD-OCT technique, we are able to demonstrate age-dependent differences in vascular function and vasodynamics.

Agmatine Modulation of Noradrenergic Neurotransmission in Isolated Rat Blood Vessels.

PubMed

Török, Jozef; Zemančíková, Anna

2016-06-30

Agmatine, a vasoactive metabolite of L-arginine, is widely distributed in mammalian tissues including blood vessels. Agmatine binding to imidazoline and α₂-adrenoceptors induces a variety of physiological and pharmacological effects. We investigated the effect of agmatine on contractile responses of the rat pulmonary artery and portal vein induced by electrical stimulation of perivascular nerves and by exogenous adrenergic substances. Experiments were performed on isolated segments of rat main pulmonary artery and its extralobular branches, and portal vein suspended in organ bath containing modified Krebs bicarbonate solution and connected to a force-displacement transducer for isometric tension recording. Electrical field stimulation (EFS) produced tetrodotoxin-sensitive contractile responses of pulmonary artery and portal vein. Besides the well known vasorelaxant actions, we found that agmatine also produced a concentration-dependent inhibition of neurogenic contractions induced by EFS in pulmonary arteries; however, the agmatine treatment did not influence the responses to exogenous noradrenaline. The inhibitory effect on EFS-induced contractions was not abolished by the α₂-adrenoceptor antagonist rauwolscine. In portal vein, in contrast, agmatine increased spontaneous mechanical contractions and enhanced the contractions induced by EFS. The results suggest that agmatine can significantly influence vascular function of pulmonary arteries and portal veins by modulating sympathetically mediated vascular contractions by pre- and postsynaptic mechanisms.

Effect of grazing seedhead-suppressed tall fescue pasture on the vasoactivity of serotonin receptors

USDA-ARS?s Scientific Manuscript database

Previous research has demonstrated that exposure to ergot alkaloids reduces vasoactivity of serotonin (5HT) receptors. Chemical suppression of tall fescue seedhead production is a tool to reduce the level of exposure to ergot alkaloids by a grazing animal. Therefore, the objective was to evaluate co...

Increasing proportions of tyrosine hydroxylase-immunoreactive interneurons colocalize with choline acetyltransferase or vasoactive intestinal peptide in the developing rat cerebral cortex

PubMed Central

Asmus, Stephen E.; Cocanougher, Benjamin T.; Allen, Donald L.; Boone, John B.; Brooks, Elizabeth A.; Hawkins, Sarah M.; Hench, Laura A.; Ijaz, Talha; Mayfield, Meredith N.

2011-01-01

Cortical interneurons are critical for information processing, and their dysfunction has been implicated in neurological disorders. One subset of this diverse cell population expresses tyrosine hydroxylase (TH) during postnatal rat development. Cortical TH-immunoreactive neurons appear at postnatal day (P) 16. The number of TH cells sharply increases between P16 and P20 and subsequently decreases to adult values. The absence of apoptotic markers in these cells suggests that the reduction in cell number is not due to cell death but is due to a decline in TH production. Cortical TH cells lack all additional catecholaminergic enzymes, and many coexpress GABA and calretinin, but little else is known about their phenotype or function. Because interneurons containing choline acetyltransferase (ChAT) or vasoactive intestinal peptide (VIP) share characteristics with cortical TH neurons, the coexpression of TH with ChAT or VIP was examined throughout the neocortex at P16, P20, and P30. The proportions of TH cell profiles double-labeled for ChAT or VIP significantly increased between P16 and P30. Based on their proximity to blood vessels, intrinsic cholinergic and VIPergic cells have been hypothesized to regulate cortical microcirculation. Labeling with the gliovascular marker aquaporin-4 revealed that at least half of the TH cells were apposed to microvessels at these ages, and many of these cells contained ChAT or VIP. Cortical TH neurons did not coproduce nitric oxide synthase. These results suggest that increasing proportions of cortical TH neurons express ChAT or VIP developmentally and that a subset of these TH neurons may regulate local blood flow. PMID:21295554

Is chronic fatigue syndrome an autoimmune disorder of endogenous neuropeptides, exogenous infection and molecular mimicry?

PubMed

Staines, Donald R

2004-01-01

Chronic fatigue syndrome is a disorder characterised by prolonged fatigue and debility and is mostly associated with post-infection sequelae although ongoing infection is unproven. Immunological aberration is likely and this may prove to be associated with an expanding group of vasoactive neuropeptides in the context of molecular mimicry and inappropriate immunological memory. Vasoactive neuropeptides including vasoactive intestinal peptide (VIP) and pituitary adenylate activating polypeptide (PACAP) belong to the secretin/glucagon superfamily and act as hormones, neurotransmitters, immune modulators and neurotrophes. They are readily catalysed to smaller peptide fragments by antibody hydrolysis. They and their binding sites are immunogenic and are known to be associated with a range of autoimmune conditions. Vasoactive neuropeptides are widely distributed in the body particularly in the central, autonomic and peripheral nervous systems and have been identified in the gut, adrenal gland, reproductive organs, vasculature, blood cells and other tissues. They have a vital role in maintaining vascular flow in organs, and in thermoregulation, memory and concentration. They are co-transmitters for acetylcholine, nitric oxide, endogenous opioids and insulin, are potent immune regulators with primarily anti-inflammatory activity, and have a significant role in protection of the nervous system to toxic assault, promotion of neural development and the maintenance of homeostasis. This paper describes a biologically plausible mechanism for the development of CFS based on loss of immunological tolerance to the vasoactive neuropeptides following infection, significant physical exercise or de novo. It is proposed that release of these substances is accompanied by a loss of tolerance either to them or their receptor binding sites in CFS. Such an occurrence would have predictably serious consequences resulting from compromised function of the key roles these substances perform. All documented symptoms of CFS are explained by vasoactive neuropeptide compromise, namely fatigue and nervous system dysfunction through impaired acetylcholine activity, myalgia through nitric oxide and endogenous opioid dysfunction, chemical sensitivity through peroxynitrite and adenosine dysfunction, and immunological disturbance through changes in immune modulation. Perverse immunological memory established against these substances or their receptors may be the reason for the protracted nature of this condition. The novel status of these substances together with their extremely small concentrations in blood and tissues means that clinical research into them is still in its infancy. A biologically plausible theory of CFS causation associated with vasoactive neuropeptide dysfunction would promote a coherent and systematic approach to research into this and other possibly associated disabling conditions.

Postnatal development of autonomic and sensory innervation of thoracic hairy skin in the rat. A histochemical, immunocytochemical, and radioenzymatic study.

PubMed

Schotzinger, R J; Landis, S C

1990-05-01

Histochemical, immunocytochemical, and radioenzymatic techniques were used to examine the neurotransmitter-related properties of the innervation of thoracic hairy skin in rats during adulthood and postnatal development. In the adult, catecholamine-containing fibers were associated with blood vessels and piloerector muscles, and ran in nerve bundles throughout the dermis. The distribution of tyrosine hydroxylase (TH)-immunoreactive (IR) fibers was identical. Neuronal fibers displaying neuropeptide Y (NPY) immunoreactivity were seen in association with blood vessels. Double-labeling studies suggested that most, if not all, NPY-IR fibers were also TH-IR and likewise most, if not all, vessel-associated TH-IR fibers were also NPY-IR. Calcitonin gene-related peptide (CGRP)-IR fibers were observed near and penetrating into the epidermis, in close association with hair follicles and blood vessels, and in nerve bundles. A similar distribution of substance P (SP)-IR fibers was evident. In adult animals treated as neonates with the sympathetic neurotoxin 6-hydroxydopamine, a virtual absence of TH-IR and NPY-IR fibers was observed, whereas the distribution of CGRP-IR and SP-IR fibers appeared unaltered. During postnatal development, a generalized increase in the number, fluorescence intensity, and varicose morphology of neuronal fibers displaying catecholamine fluorescence, NPY-IR, CGRP-IR, and SP-IR was observed. By postnatal day 21, the distribution of the above fibers had reached essentially adult levels, although the density of epidermal-associated CGRP-IR and SP-IR fibers was significantly greater than in the adult. The following were not evident in thoracic hairy skin at any timepoint examined: choline acetyltransferase activity, acetylcholinesterase histochemical staining or immunoreactivity, fibers displaying immunoreactivity to vasoactive intestinal peptide, cholecystokinin, or leucine-enkephalin. The present study demonstrates that the thoracic hairy skin in developing and adult rats receives an abundant sympathetic catecholaminergic and sensory innervation, but not a cholinergic innervation.

Vasoactive intestinal polypeptide (VIP) innervation of the human eyelid glands.

PubMed

Seifert, P; Spitznas, M

1999-06-01

This study was conducted to obtain morphological proof of innervating nerve fibres in the glands of the human eyelid (accessory lacrimal glands of Wolfring, meibomian glands, goblet cells, glands of Zeis, glands of Moll, sweat glands, glands of lanugo hair follicles) and identification of the secretomotorically active neuropeptide vasoactive intestinal polypeptide (VIP) as a common transmitter. Epoxy-embedded ultrathin sections of tissue samples from human eyelids were studied using electron microscopy. Paraffin sections fixed in Bouin-Hollande solution were immunostained with rabbit antiserum against VIP. With the electron microscope we were able to identify nerves in the glandular stroma of all the glands examined with the exception of goblet cells. Intraepithelial single axons were only seen in the parenchyma of Wolfring glands. The morphological findings corresponded with the immunological finding of VIP-positive, nerve-like structures in the same locations, with the exception of lanugo hair follicle glands, and goblet cells. Our findings indicate that the glands of the eyelids and main lacrimal gland represent a functional unit with VIP as a possible common stimulating factor. Copyright 1999 Academic Press.

Magnesium sulphate and (123)I-MIBG in pheochromocytoma: Two useful techniques for a complicated disease.

PubMed

Vendrell, M; Martín, N; Tejedor, A; Ortiz, J T; Muxí, À; Taurà, P

2016-01-01

Pheochromocytoma is a tumour of the chromaffin tissue. It may, through catecholamine release, have deleterious effects on myocardial structure. A 48-year-old woman with a history of hypertension and type II diabetes mellitus (ASA II) was diagnosed of pheochromocytoma-induced myocarditis, which caused severe cardiogenic shock, with an ejection fraction of 20%. Extreme blood pressure swings required aggressive therapy with vasoactive drugs (norepinephrine and dopamine) and an intra-aortic balloon pump, despite which severe haemodynamic instability persisted. Finally, the use of magnesium sulphate allowed for cardiovascular stabilization and weaning off vasoactive drugs prior to surgery. (123)I-metaiodobenzylguanidine scintigraphy helps not only to functionally confirm tumour tissue, but also to assess severity and prognosis of cardiac failure. Prognosis of pheochromocytoma-induced heart failure can be very poor. The use of these two well-known and relatively simple 'tools' for treatment and prognosis is a helpful option to keep in mind. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Vasoactive Intestinal Peptide Inhibits Human Small-Cell Lung Cancer Proliferation in vitro and in vivo

NASA Astrophysics Data System (ADS)

Maruno, Kaname; Absood, Afaf; Said, Sami I.

1998-11-01

Small-cell lung carcinoma (SCLC) is an aggressive, rapidly growing and metastasizing, and highly fatal neoplasm. We report that vasoactive intestinal peptide inhibits the proliferation of SCLC cells in culture and dramatically suppresses the growth of SCLC tumor-cell implants in athymic nude mice. In both cases, the inhibition was mediated apparently by a cAMP-dependent mechanism, because the inhibition was enhanced by the adenylate cyclase activator forskolin and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine in proportion to increases in intracellular cAMP levels, and the inhibition was abolished by selective inhibition of cAMP-dependent protein kinase. If confirmed in clinical trials, this antiproliferative action of vasoactive intestinal peptide may offer a new and promising means of suppressing SCLC in human subjects, without the toxic side effects of chemotherapeutic agents.

cAMP signalling in the vasculature: the role of Epac (exchange protein directly activated by cAMP).

PubMed

Roberts, Owain Llŷr; Dart, Caroline

2014-02-01

The second messenger cAMP plays a central role in mediating vascular smooth muscle relaxation in response to vasoactive transmitters and in strengthening endothelial cell-cell junctions that regulate the movement of solutes, cells and macromolecules between the blood and the surrounding tissue. The vasculature expresses three cAMP effector proteins: PKA (protein kinase A), CNG (cyclic-nucleotide-gated) ion channels, and the most recently discovered Epacs (exchange proteins directly activated by cAMP). Epacs are a family of GEFs (guanine-nucleotide-exchange factors) for the small Ras-related GTPases Rap1 and Rap2, and are being increasingly implicated as important mediators of cAMP signalling, both in their own right and in parallel with the prototypical cAMP target PKA. In the present paper, we review what is currently known about the role of Epac within blood vessels, particularly with regard to the regulation of vascular tone, endothelial barrier function and inflammation.

Factors Associated with the Incidence and Severity of New-Onset Atrial Fibrillation in Adult Critically Ill Patients

PubMed Central

Leichtweis, Gustavo Elias; Andriolo, Luiza; Delevatti, Yasmim A.; Jorge, Amaury C.; Fumagalli, Andreia C.; Santos, Luiz Claudio; Miura, Cecilia K.; Saito, Sergio K.

2017-01-01

Background Acute Atrial Fibrillation (AF) is common in critically ill patients, with significant morbidity and mortality; however, its incidence and severity in Intensive Care Units (ICUs) from low-income countries are poorly studied. Additionally, impact of vasoactive drugs on its incidence and severity is still not understood. This study aimed to assess epidemiology and risk factors for acute new-onset AF in critically ill adult patients and the role of vasoactive drugs. Method Cohort performed in seven general ICUs (including cardiac surgery) in three cities in Paraná State (southern Brazil) for 45 days. Patients were followed until hospital discharge. Results Among 430 patients evaluated, the incidence of acute new-onset AF was 11.2%. Patients with AF had higher ICU and hospital mortality. Vasoactive drugs use (norepinephrine and dobutamine) was correlated with higher incidence of AF and higher mortality in patients with AF; vasopressin (though used in few patients) had no effect on development of AF. Conclusions In general ICU patients, incidence of new-onset AF was 11.2% with a high impact on morbidity and mortality, particularly associated with the presence of Acute Renal Failure. The use of vasoactive drugs (norepinephrine and dobutamine) could lead to a higher incidence of new-onset AF-associated morbidity and mortality. PMID:28702263

Factors Associated with the Incidence and Severity of New-Onset Atrial Fibrillation in Adult Critically Ill Patients.

PubMed

Duarte, Péricles A D; Leichtweis, Gustavo Elias; Andriolo, Luiza; Delevatti, Yasmim A; Jorge, Amaury C; Fumagalli, Andreia C; Santos, Luiz Claudio; Miura, Cecilia K; Saito, Sergio K

2017-01-01

Acute Atrial Fibrillation (AF) is common in critically ill patients, with significant morbidity and mortality; however, its incidence and severity in Intensive Care Units (ICUs) from low-income countries are poorly studied. Additionally, impact of vasoactive drugs on its incidence and severity is still not understood. This study aimed to assess epidemiology and risk factors for acute new-onset AF in critically ill adult patients and the role of vasoactive drugs. Cohort performed in seven general ICUs (including cardiac surgery) in three cities in Paraná State (southern Brazil) for 45 days. Patients were followed until hospital discharge. Among 430 patients evaluated, the incidence of acute new-onset AF was 11.2%. Patients with AF had higher ICU and hospital mortality. Vasoactive drugs use (norepinephrine and dobutamine) was correlated with higher incidence of AF and higher mortality in patients with AF; vasopressin (though used in few patients) had no effect on development of AF. In general ICU patients, incidence of new-onset AF was 11.2% with a high impact on morbidity and mortality, particularly associated with the presence of Acute Renal Failure. The use of vasoactive drugs (norepinephrine and dobutamine) could lead to a higher incidence of new-onset AF-associated morbidity and mortality.

Isolation and amino acid sequences of opossum vasoactive intestinal polypeptide and cholecystokinin octapeptide.

PubMed Central

Eng, J; Yu, J; Rattan, S; Yalow, R S

1992-01-01

Evolutionary history suggests that the marsupials entered South America from North America about 75 million years ago and subsequently dispersed into Australia before the separation between South America and Antarctica-Australia. A question of interest is whether marsupial peptides resemble the corresponding peptides of Old or New World mammals. Previous studies had shown that "little" gastrin of the North American marsupial, the opossum, is identical in length to that of the New World mammals, the guinea pig and chinchilla. In this report, we demonstrate that opossum cholecystokinin octapeptide, like that of the Australian marsupials, the Eastern quoll and the Tamar wallaby, is identical to the cholecystokinin octapeptide of Old World mammals and differs from that of the guinea pig and chinchilla. However, opossum vasoactive intestinal polypeptide differs from the usual Old World mammalian vasoactive intestinal polypeptide in five sites: [sequence; see text]. PMID:1542675

Modulation of inflammation by vasoactive intestinal peptide and bombesin: lack of effects on neutrophil apoptosis.

PubMed

Djanani, Angela M; Kähler, Ch M

2002-01-01

Inhibition of neutrophil apoptosis has been identified as a prominent feature in chronic inflammation, parenchymal damage, and unresolved organ dysfunction. Lung injury animal models suggest that the neuropeptides vasoactive intestinal peptide and bombesin are protective. Therefore, in vitro effects of VIP and bombesin on apoptosis of normal human neutrophils were tested. For measuring effects on cell survival and apoptosis, trypan dye exclusion, colorimetric MTT assay to assess cell survival, and caspase-3 assay and annexin-V binding for analysing apoptosis rates were used. Foetal calf serum, Fas ligand, and tumour necrosis factor-alpha served as modulatory control agents; survival-promoting and apoptosis-inducing activities of the respective agents were confirmed. Vasoactive intestinal peptide and bombesin, however, failed to significantly affect cell death in neutrophils. Data suggest that direct regulation of neutrophil apoptosis is unlikely to be among the mechanisms of lung-protective actions of VIP and bombesin.

Enhancement of allergic skin wheal responses in patients with atopic eczema/dermatitis syndrome by playing video games or by a frequently ringing mobile phone.

PubMed

Kimata, H

2003-06-01

Playing video games causes physical and psychological stress, including increased heart rate and blood pressure and aggression-related feelings. Use of mobile phones is very popular in Japan, and frequent ringing is a common and intrusive part of Japanese life. Atopic eczema/dermatitis syndrome is often exacerbated by stress. Stress increases serum IgE levels, skews cytokine pattern towards Th2 type, enhances allergen-induced skin wheal responses, and triggers mast cell degranulation via substance P, vasoactive intestinal peptide and nerve growth factor. (1). In the video game study, normal subjects (n = 25), patients with allergic rhinitis (n = 25) or atopic eczema/dermatitis syndrome (n = 25) played a video game (STREET FIGHTER II) for 2 h. Before and after the study, allergen-induced wheal responses, plasma levels of substance P, vasoactive intestinal peptide and nerve growth factor, and in vitro production of total IgE, antihouse dust mite IgE and cytokines were measured. (2). In the mobile phone study, normal subjects (n = 27), patients with allergic rhinitis (n = 27) or atopic eczema/dermatitis syndrome (n = 27) were exposed to 30 incidences of ringing mobile phones during 30 min. Before and after the study, allergen-induced wheal responses, plasma levels of substance P, vasoactive intestinal peptide and nerve growth factor were measured. Playing video games had no effect on the normal subjects or the patients with allergic rhinitis. In contrast, playing video games significantly enhanced allergen-induced skin wheal responses and increased plasma levels of substance P, vasoactive intestinal peptide and nerve growth factors in the patients with atopic eczema/dermatitis syndrome. Moreover, playing video games enhanced in vitro production of total IgE and anti-house dust mite IgE with concomitant increased production of IL-4, IL-10 and IL-13 and decreased production of IFN-gamma and IL-12 in the patients with atopic eczema/dermatitis syndrome. However, exposure to frequently ringing mobile phones significantly enhanced allergen-induced skin wheal responses, plasma levels of substance P, vasoactive intestinal peptide and nerve growth factors in the patients with atopic eczema/dermatitis syndrome, but not in the normal subjects or the patients with allergic rhinitis. Playing video games enhanced allergic responses with a concomitant increased release of substance P, vasoactive intestinal peptide and nerve growth factor, and skewing of the cytokine pattern toward Th2 type in the patients with atopic eczema/dermatitis syndrome. In addition, exposure to frequently ringing mobile phones also enhanced allergic responses with a concomitant increased release of substance P, vasoactive intestinal peptide and nerve growth factor Collectively, high technology causes stress, which in turn may aggravate symptoms of atopic eczema/dermatitis syndrome.

Circumferentially aligned fibers guided functional neoartery regeneration in vivo.

PubMed

Zhu, Meifeng; Wang, Zhihong; Zhang, Jiamin; Wang, Lina; Yang, Xiaohu; Chen, Jingrui; Fan, Guanwei; Ji, Shenglu; Xing, Cheng; Wang, Kai; Zhao, Qiang; Zhu, Yan; Kong, Deling; Wang, Lianyong

2015-08-01

An ideal vascular graft should have the ability to guide the regeneration of neovessels with structure and function similar to those of the native blood vessels. Regeneration of vascular smooth muscle cells (VSMCs) with circumferential orientation within the grafts is crucial for functional vascular reconstruction in vivo. To date, designing and fabricating a vascular graft with well-defined geometric cues to facilitate simultaneously VSMCs infiltration and their circumferential alignment remains a great challenge and scarcely reported in vivo. Thus, we have designed a bi-layered vascular graft, of which the internal layer is composed of circumferentially aligned microfibers prepared by wet-spinning and an external layer composed of random nanofibers prepared by electrospinning. While the internal circumferentially aligned microfibers provide topographic guidance for in vivo regeneration of circumferentially aligned VSMCs, the external random nanofibers can offer enhanced mechanical property and prevent bleeding during and after graft implantation. VSMCs infiltration and alignment within the scaffold was then evaluated in vitro and in vivo. Our results demonstrated that the circumferentially oriented VSMCs and longitudinally aligned ECs were successfully regenerated in vivo after the bi-layered vascular grafts were implanted in rat abdominal aorta. No formation of thrombosis or intimal hyperplasia was observed up to 3 month post implantation. Further, the regenerated neoartery exhibited contraction and relaxation property in response to vasoactive agents. This new strategy may bring cell-free small diameter vascular grafts closer to clinical application. Copyright © 2015 Elsevier Ltd. All rights reserved.

Association of vasoactive intestinal peptide with polymer-grafted liposomes: structural aspects for pulmonary delivery.

PubMed

Stark, Brigitte; Debbage, Paul; Andreae, Fritz; Mosgoeller, Wilhelm; Prassl, Ruth

2007-03-01

A polymer-grafted liposomal formulation that has the potential to be developed for aerosolic pulmonary delivery of vasoactive intestinal peptide (VIP), a potent vasodilatory neuropeptide, is described. As VIP is prone to rapid proteolytic degradation in the microenvironment of the lung a proper delivery system is required to increase the half-life and bioavailability of the peptide. Here we investigate structural parameters of unilamellar liposomes composed of palmitoyl-oleoyl-phosphatidylcholine, lyso-stearyl-phosphatidylglycerol and distearyl-phosphatidyl-ethanolamine covalently linked to polyethylene glycol 2000, and report on VIP-lipid interaction mechanisms. We found that the cationic VIP is efficiently entrapped by the negatively charged spherical liposomes and becomes converted to an amphipathic alpha-helix. By fluorescence spectroscopy using single Trp-modified VIP we could show that VIP is closely associated to the membrane. Our data suggest that the N-terminal random-coiled domain is embedded in the interfacial headgroup region of the phospholipid bilayer. By doing so, neither the bilayer thickness of the lipid membrane nor the mobility of the phospholipid acyl chains are affected as shown by small angle X-ray scattering and electron spin resonance spectroscopy. Finally, in an ex vivo lung arterial model system we found that liposomal-associated VIP is recognized by its receptors to induce vasodilatory effects with comparable high relaxation efficiency as free VIP but with a significantly retarded dilatation kinetics. In conclusion, we have designed and characterized a liposomal formulation that is qualified to entrap biologically active VIP and displays structural features to be considered for delivery of VIP to the lung.

Microvascular dysfunction with increased vascular leakage response in mice systemically exposed to arsenic.

PubMed

Chen, Shih-Chieh; Huang, Shin-Yin; Lu, Chi-Yu; Hsu, Ya-Hung; Wang, Dean-Chuan

2014-09-01

The mechanisms underlying cardiovascular disease induced by arsenic exposure are not completely understood. The objectives of this study were to investigate whether arsenic-fed mice have an increased vascular leakage response to vasoactive agents and whether enhanced type-2 protein phosphatase (PP2A) activity is involved in mustard oil-induced leakage. ICR mice were fed water or sodium arsenite (20 mg/kg) for 4 or 8 weeks. The leakage response to vasoactive agents was quantified using the Evans blue (EB) technique or vascular labeling with carbon particles. Increased EB leakage and high density of carbon-labeled microvessels were detected in arsenic-fed mice treated with mustard oil. Histamine induced significantly higher vascular leakage in arsenic-fed mice than in water-fed mice. Pretreatment with the PP2A inhibitor okadaic acid or the neurokinin 1 receptor (NK1R) blocker RP67580 significantly reduced mustard oil-induced vascular leakage in arsenic-fed mice. The protein levels of PP2Ac and NK1R were similar in both groups. PP2A activity was significantly higher in the arsenic-fed mice compared with the control group. These findings indicate that microvessels generally respond to vasoactive agents, and that the increased PP2A activity is involved in mustard oil-induced vascular leakage in arsenic-fed mice. Arsenic may initiate endothelial dysfunction, resulting in vascular leakage in response to vasoactive agents.

Effect of co-medication on the pharmacokinetic parameters of phenobarbital in asphyxiated newborns.

PubMed

Šíma, M; Pokorná, P; Hronová, K; Slanař, O

2015-01-01

Phenobarbital is an anticonvulsive drug widely used in newborns with hypoxic-ischemic encephalopathy. The objective of our study was to describe possible effect of frequently co-administered medications (dopamine, dobutamine, norepinephrine, furosemide, phenytoin, and analgesics) on the phenobarbital pharmacokinetics in full term newborns with hypoxic-ischemic encephalopathy. Phenobarbital pharmacokinetic parameters (standardized intravenous loading dose was 10-20 mg/kg, maintenance dose 2-6 mg/kg/day) were computed using non-compartmental analysis. Co-medication was evaluated throughout the whole treatment period up to 5 days. Volume of distribution, clearance, and half-life median values (95 % CI) for phenobarbital in the whole study population (n=37) were 0.48 (0.41-0.56) l/kg, 0.0034 (0.0028-0.0040) l/h/kg, and 93.7 (88.1-99.2) h, respectively. Phenobarbital pharmacokinetic parameters were not significantly affected by vasoactive drugs (dopamine, dobutamine, and norepinephrine), furosemide, phenytoin, or analgesics. Furthermore, no dose-dependent alteration of phenobarbital pharmacokinetic parameters was noted for vasoactive medication at doses equivalent to cumulative vasoactive-inotropic score (area under the curve in a plot of vasoactive-inotropic score against time) 143.2-8473.6, furosemide at cumulative doses of 0.2-42.9 mg/kg, or phenytoin at cumulative doses of 10.3-46.2 mg/kg. Phenobarbital pharmacokinetics was not affected by investigated co-administered drugs used in newborns with hypoxic-ischemic encephalopathy in real clinical settings.

Infection-Mediated Vasoactive Peptides Modulate Cochlear Uptake of Fluorescent Gentamicin

PubMed Central

Koo, Ja-Won; Wang, Qi; Steyger, Peter S.

2011-01-01

Inflammatory mediators released during bacterial infection include vasoactive peptides such as histamine and serotonin, and their serum levels are frequently elevated. These peptides also modulate the vascular permeability of endothelial cells lining the blood-brain and blood-labyrinth barriers (BLB). These peptides may also modulate the permeability of the BLB to ototoxic aminoglycoside antibiotics prescribed to resolve bacterial sepsis. To test this hypothesis, we compared the effect of histamine and serotonin on the cochlear distribution of fluorescently conjugated gentamicin (GTTR) in control animals at 0.5, 1 and 3 h after injection of GTTR. The intensity of GTTR fluorescence was attenuated at 1 h in the histamine group compared to control mice, and more intense 3 h after injection (p < 0.05). In the serotonin group, the intensity of GTTR fluorescence was attenuated at 0.5 and 1 h (p < 0.05) and was increased at 3 h compared to control animals, where GTTR intensities peaked at 1 h and then plateaued or was slightly decreased at 3 h. This biphasic pattern of modulation was statistically significant in the apical turn of the cochlea. No difference in the intensity of GTTR fluorescence was observed in kidney proximal tubules. Systemic increases in serum levels of vasoactive peptides can modulate cochlear uptake of gentamicin, likely via permeability changes in the BLB. Conditions that influence serum levels of vasoactive peptides may potentiate aminoglycoside ototoxicity. PMID:21196726

Superconducting magnetic energy storage apparatus structural support system

DOEpatents

Withers, Gregory J.; Meier, Stephen W.; Walter, Robert J.; Child, Michael D.; DeGraaf, Douglas W.

1992-01-01

A superconducting magnetic energy storage apparatus comprising a cylindrical superconducting coil; a cylindrical coil containment vessel enclosing the coil and adapted to hold a liquid, such as liquefied helium; and a cylindrical vacuum vessel enclosing the coil containment vessel and located in a restraining structure having inner and outer circumferential walls and a floor; the apparatus being provided with horizontal compression members between (1) the coil and the coil containment vessel and (2) between the coil containment vessel and the vacuum vessel, compression bearing members between the vacuum vessel and the restraining structure inner and outer walls, vertical support members (1) between the coil bottom and the coil containment vessel bottom and (2) between the coil containment vessel bottom and the vacuum vessel bottom, and external supports between the vacuum vessel bottom and the restraining structure floor, whereby the loads developed by thermal and magnetic energy changes in the apparatus can be accommodated and the structural integrity of the apparatus be maintained.

Evacuated optical structure comprising optical bench mounted to sidewall of vacuum chamber in a manner which inhibits deflection and rotation of the optical bench

DOEpatents

Bowers, Joel M.

1994-01-01

An improved evacuated optical structure is disclosed comprising an optical bench mounted in a vacuum vessel in a manner which inhibits transmission of movement of the vacuum vessel to the optical bench, yet provides a compact and economical structure. The vacuum vessel is mounted, through a sidewall thereof, to a support wall at four symmetrically positioned and spaced apart areas, each of which comprises a symmetrically positioned group of mounting structures passing through the sidewall of the vacuum vessel. The optical bench is pivotally secured to the vacuum vessel by four symmetrically spaced apart bolts and spherical bearings, each of which is centrally positioned within one of the four symmetrically positioned groups of vacuum vessel mounting structures. Cover plates and o-ring seals are further provided to seal the vacuum vessel mounting structures from the interior of the vacuum vessel, and venting bores are provided to vent trapped gases in the bores used to secure the cover plates and o-rings to the vacuum vessel. Provision for detecting leaks in the mounting structures from the rear surface of the vacuum vessel sidewall facing the support wall are also provided. Deflection to the optical bench within the vacuum vessel is further minimized by tuning the structure for a resonant frequency of at least 100 Hertz.

Evacuated optical structure comprising optical bench mounted to sidewall of vacuum chamber in a manner which inhibits deflection and rotation of the optical bench

DOEpatents

Bowers, J.M.

1994-04-19

An improved evacuated optical structure is disclosed comprising an optical bench mounted in a vacuum vessel in a manner which inhibits transmission of movement of the vacuum vessel to the optical bench, yet provides a compact and economical structure. The vacuum vessel is mounted, through a sidewall thereof, to a support wall at four symmetrically positioned and spaced apart areas, each of which comprises a symmetrically positioned group of mounting structures passing through the sidewall of the vacuum vessel. The optical bench is pivotally secured to the vacuum vessel by four symmetrically spaced apart bolts and spherical bearings, each of which is centrally positioned within one of the four symmetrically positioned groups of vacuum vessel mounting structures. Cover plates and o-ring seals are further provided to seal the vacuum vessel mounting structures from the interior of the vacuum vessel, and venting bores are provided to vent trapped gases in the bores used to secure the cover plates and o-rings to the vacuum vessel. Provision for detecting leaks in the mounting structures from the rear surface of the vacuum vessel sidewall facing the support wall are also provided. Deflection to the optical bench within the vacuum vessel is further minimized by tuning the structure for a resonant frequency of at least 100 Hertz. 10 figures.

Modulation of bicarbonate secretion in rabbit duodenum: the role of calcium.

PubMed

Hogan, D L; Yao, B; Isenberg, J I

1998-01-01

Surface epithelial bicarbonate secretion protects the proximal duodenum from acid peptic injury. Cyclic adenosine monophosphate and calcium serve as intracellular mediators of intestinal transport. Experiments were performed to examine whether calcium participates in duodenal bicarbonate transport. Stripped duodenal mucosa from rabbits was studied in Ussing chambers. HCO3- transport was stimulated by the calcium ionophore A23187, carbachol, vasoactive intestinal peptide, prostaglandin E2, dibutyryl-cyclic adenosine monophosphate, and electrical field stimulation. A23187 stimulated HCO3- secretion and Isc; tetrodotoxin failed to inhibit this effect. The calcium-channel blocker verapamil abolished HCO3- secretion stimulated by carbachol, vasoactive intestinal peptide, and electrical field stimulation, but failed to alter basal, prostaglandin E2- or dibutyryl-cyclic adenosine monophosphate-stimulated HCO3- secretion. Therefore, calcium is likely required during stimulation of duodenal epithelial HCO3- transport by carbachol, vasoactive intestinal peptide, and electrical field stimulation. Prostaglandin E2 and dibutyryl-cyclic adenosine monophosphate appear to activate duodenal HCO3- secretion by a calcium-independent pathway(s).

Biochemical factors modulating female genital sexual arousal physiology.

PubMed

Traish, Abdulmaged M; Botchevar, Ella; Kim, Noel N

2010-09-01

Female genital sexual arousal responses are complex neurophysiological processes consisting of central and peripheral components that occur following sexual stimulation. The peripheral responses in sexual arousal include genital vasocongestion, engorgement and lubrication resulting from a surge of vaginal and clitoral blood flow. These hemodynamic events are mediated by a host of neurotransmitters and vasoactive agents. To discuss the role of various biochemical factors modulating female genital sexual arousal responses. A comprehensive literature review was conducted using the PubMed database and citations were selected, based on topical relevance, and examined for study methodology and major findings. Data from peer-reviewed publications. Adrenergic as well as non-adrenergic non-cholinergic neurotransmitters play an important role in regulating genital physiological responses by mediating vascular and non-vascular smooth muscle contractility. Vasoactive peptides and neuropeptides also modulate genital sexual responses by regulating vascular and non-vascular smooth muscle cells and epithelial function. The endocrine milieu, particularly sex steroid hormones, is critical in the maintenance of tissue structure and function. Reduced levels of estrogens and androgen are associated with dramatic alterations in genital tissue structure, including the nerve network, as well as the response to physiological modulators. Furthermore, estrogen and androgen deficiency is associated with reduced expression of sex steroid receptors and most importantly with attenuated genital blood flow and lubrication in response to pelvic nerve stimulation. This article provides an integrated framework describing the physiological and molecular basis of various pathophysiological conditions associated with female genital sexual arousal dysfunction. © 2010 International Society for Sexual Medicine.

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.

Deficient Vasoactive Intestinal Peptide Innervation in the Sweat Glands of Cystic Fibrosis Patients

NASA Astrophysics Data System (ADS)

Heinz-Erian, Peter; Dey, Richard D.; Flux, Marinus; Said, Sami I.

1985-09-01

The innervation of acini and ducts of eccrine sweat glands by immunoreactive, vasoactive intestinal peptide--containing nerve fibers was sharply reduced in seven patients with cystic fibrosis compared to eight normal subjects. The decrease in innervation by this neuropeptide, which has been shown to promote blood flow and the movement of water and chloride across epithelial surfaces in other systems, may be a basic mechanism for the decreased water content and relative impermeability of the epithelium to chloride and other ions that characterize cystic fibrosis.

Evidence against vasoactive intestinal polypeptide (VIP) as a dilator and in favour of substance P as a constrictor in airway neurogenic responses.

PubMed

Karlsson, J A; Persson, C G

1983-07-01

Propranolol-resistant neurogenic relaxation persisted in (carbachol-contracted) guinea-pig tracheae already relaxed by supramaximal concentrations of vasoactive intestinal polypeptide (VIP). Also, VIP relaxed preparations that were under neurogenic inhibition. In hilus bronchi, about 60% of a neurogenic contraction was atropine-resistant. (Arg5, D-Trp7.9) SP 5-11 specifically antagonized this contraction and those produced by exogenous substance P. Substance P, but not VIP, seems to be involved in nerve-mediated effects on guinea-pig airway tone.

Automatic detection of lung vessel bifurcation in thoracic CT images

NASA Astrophysics Data System (ADS)

Maduskar, Pragnya; Vikal, Siddharth; Devarakota, Pandu

2011-03-01

Computer-aided diagnosis (CAD) systems for detection of lung nodules have been an active topic of research for last few years. It is desirable that a CAD system should generate very low false positives (FPs) while maintaining high sensitivity. This work aims to reduce the number of false positives occurring at vessel bifurcation point. FPs occur quite frequently on vessel branching point due to its shape which can appear locally spherical due to the intrinsic geometry of intersecting tubular vessel structures combined with partial volume effects and soft tissue attenuation appearance surrounded by parenchyma. We propose a model-based technique for detection of vessel branching points using skeletonization, followed by branch-point analysis. First we perform vessel structure enhancement using a multi-scale Hessian filter to accurately segment tubular structures of various sizes followed by thresholding to get binary vessel structure segmentation [6]. A modified Reebgraph [7] is applied next to extract the critical points of structure and these are joined by a nearest neighbor criterion to obtain complete skeletal model of vessel structure. Finally, the skeletal model is traversed to identify branch points, and extract metrics including individual branch length, number of branches and angle between various branches. Results on 80 sub-volumes consisting of 60 actual vessel-branching and 20 solitary solid nodules show that the algorithm identified correctly vessel branching points for 57 sub-volumes (95% sensitivity) and misclassified 2 nodules as vessel branch. Thus, this technique has potential in explicit identification of vessel branching points for general vessel analysis, and could be useful in false positive reduction in a lung CAD system.

46 CFR 28.385 - Structural fire protection for vessels that operate with more than 49 individuals on board.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Requirements for Vessels...) Construction. The hull, structural bulkheads, columns and stanchions must be composed of steel. Superstructures...

Non-invasive method and apparatus for measuring pressure within a pliable vessel

NASA Technical Reports Server (NTRS)

Shimizu, M. (Inventor)

1983-01-01

A non-invasive method and apparatus is disclosed for measuring pressure within a pliable vessel such as a blood vessel. The blood vessel is clamped by means of a clamping structure having a first portion housing a pressure sensor and a second portion extending over the remote side of the blood vessel for pressing the blood vessel into engagement with the pressure sensing device. The pressure sensing device includes a flat deflectable diaphragm portion arranged to engage a portion of the blood vessel flattened against the diaphragm by means of the clamp structure. In one embodiment, the clamp structure includes first and second semicylindrical members held together by retaining rings. In a second embodiment the clamp structure is of one piece construction having a solid semicylindrical portion and a hollow semicylindrical portion with a longitudinal slot in the follow semicylindrical portion through which a slip the blood vessel. In a third embodiment, an elastic strap is employed for clamping the blood vessel against the pressure sensing device.

Red cell substitutes.

PubMed

Winslow, Robert M

2007-01-01

Oxygen-carrying plasma expanders (blood substitutes) have been sought for over a century. Development of current products is a result of evolution in the understanding of proteins in general, of hemoglobin in particular, and of how cell-free hemoglobin interacts with the control of local blood flow to ensure adequate tissue oxygenation. Hemoglobin-based products are considered in four "generations" corresponding to major improvements. First-generation products consisted of hemoglobin, freed of red cell membranes (stroma-free hemoglobin [SFH]), which was renal toxic and vasoactive. Second-generation products were polymerized with aldehyde reagents to reduce or eliminate the renal toxicity, but the products were heterogeneous and still vasoactive. Third-generation products employed more specific intramolecular crosslinking to eliminate polymerization and promote homogeneity, but they also remained vasoactive. Fourth-generation products are based on a new understanding of the way in which microvascular blood flow is controlled and the influence of O(2) delivery to vascular walls. After more than a century of research, one of these new solutions should find use as an alternative to red cells for transfusion in certain clinical settings.

Active immunization against endothelin-1 is associated with a decrease in plasma endothelin-1 and changes in vascular reactivity.

PubMed

Grafov, M A; Gavrilova, S A; Rubina AYu; Masenko, V P; Medvedeva, N A

2000-11-01

Exogenous endothelin-1 (ET-1) or high concentrations of the peptide in pathological conditions have marked effects on vascular reactivity. In order to evaluate the role of endogenous ET-1 we investigated responsiveness of conduit (aorta) and of resistant-like (tail artery) vessels in ET-1-deficient rats. Elimination of circulating ET-1 was achieved by active immunization of Wistar rats with a peptide-haemocyanin conjugate (anti-ET-1 group), leading to a marked reduction in plasma level of the peptide in comparison with that of vehicle-treated animals (control group): 1.9 fmol/ml vs 4.9 fmol/ml, respectively. The immunization was associated with a slight elevation of mean arterial pressure, whereas heart rate remained unchanged. In the anti-ET-1 group rings of isolated aorta displayed reduced sensitivity to ET-1: EC50 = 6.57 nM vs 2.95 nM in the control group. Tail arteries of the ET-1-deficient rats showed diminished responses to ET-1, the maximal rise in perfusion pressure: +5.2 mmHg vs +13.6 mmHg in the control group. After immunization, rings of isolated aorta displayed no changes in endothelium-dependent relaxation to acetylcholine (Ach, EC50 = 0.20 microM vs 0.35 microM in the control group), whereas experiments on perfused tail artery showed a twofold reduction in Ach effects. Thus, depletion of circulating ET-1 induces slight changes in haemodynamics associated with altered vessel responsiveness to vasoactive substances.

PAF involvement in dermal extravasation in the reverse passive Arthus reaction

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

Deacon, R.W.; Melden, M.K.; Saunders, R.N.

The reverse passive erthus reaction (RPAR) is characterized by PMN infiltration, increased vascular permeability leading to plasma extravasation and vessel damage. In the skin RPAR is an inflammatory response initiated by deposition of immune complexes and attributed to complement activation. As PAF can elicit similar dermal reactions, they examined the PAF antagonist SRI 63-072 in the RPAR. Guinea pigs were given an i.v. injection of /sup 125/I-BSA (Ag-20 mg/kg with 20 mg/kg Evan's blue as a permeability tracer), followed by intradermal (i.d.) injections (0.1 ml/site) of anti-BSA antibodies (Ab). After 30 min, dermal sites (2 cm diam.) were removed, countedmore » and the ..mu..l plasma/site (over background counts) calculated from plasma radioactivity measurements. The plasma leakage (..mu..l plasma/site) was dose-dependent upon Ab dose (6-200 ..mu..g/site). At the ultrastructural level, the presence of neutrophils and eosinophils were observed in the extravascular spaces. The luminal endothelium exhibited cytotoxic characteristics and loss of junctional integrity. SRI 63-072 exhibited 50% maximal inhibition when given i.d. with the Ab (0.1 ..mu..g/site) but only 5-10% when given at 3.0 mg/kg i.v. with Ag. No further inhibition of dermal extravasation was observed using SRI 63-441, a competitive receptor antagonist with 3-30 fold the in vivo potency of SRI 63-072. As dermal extravasation in RPAR is only partially inhibited by a PAF antagonist, it appears that other vasoactive mediators, possibly histamine, may be influencing vessel permeability as well.« less

Copper induces vasorelaxation and antagonizes noradrenaline-induced vasoconstriction in rat mesenteric artery.

PubMed

Wang, Yu-Chun; Hu, Chao-Wei; Liu, Ming-Yu; Jiang, Hong-Chao; Huo, Rong; Dong, De-Li

2013-01-01

Copper is an essential trace element for normal cellular function and contributes to critical physiological or pathological processes. The aim of the study was to investigate the effects of copper on vascular tone of rat mesenteric artery and compare the effects of copper on noradrenaline (NA) and high K(+) induced vasoconstriction. The rat mesenteric arteries were isolated and the vessel tone was measured by using multi wire myograph system in vitro. Blood pressure of carotid artery in rabbits was measured by using physiological data acquisition and analysis system in vivo. Copper dose-dependently blunted NA-induced vasoconstriction of rat mesenteric artery. Copper-induced vasorelaxation was inhibited when the vessels were pretreated with NG-nitro-L-arginine methyl ester (L-NAME). Copper did not blunt high K(+)-induced vasoconstriction. Copper preincubation inhibited NA-evoked vasoconstriction and the inhibition was not affected by the presence of L-NAME. Copper preincubation showed no effect on high K(+)-evoked vasoconstriction. Copper chelator diethyldithiocarbamate trihydrate (DTC) antagonized the vasoactivity induced by copper in rat mesenteric artery. In vivo experiments showed that copper injection (iv) significantly decreased blood pressure of rabbits and NA or DTC injection (iv) did not rescue the copper-induced hypotension and animal death. Copper blunted NA but not high K(+)-induced vasoconstriction of rat mesenteric artery. The acute effect of copper on NA-induced vasoconstriction was depended on nitric oxide (NO), but the effect of copper pretreatment on NA-induced vasoconstriction was independed on NO, suggesting that copper affected NA-induced vasoconstriction by two distinct mechanisms. © 2013 S. Karger AG, Basel.

beta(2)-adrenoceptor antagonist ICI 118,551 decreases pulmonary vascular tone in mice via a G(i/o) protein/nitric oxide-coupled pathway.

PubMed

Wenzel, Daniela; Knies, Ralf; Matthey, Michaela; Klein, Alexandra M; Welschoff, Julia; Stolle, Vanessa; Sasse, Philipp; Röll, Wilhelm; Breuer, Johannes; Fleischmann, Bernd K

2009-07-01

beta(2)-adrenoceptors are important modulators of vascular tone, particularly in the pulmonary circulation. Because neurohormonal activation occurs in pulmonary arterial hypertension, we have investigated the effect of different adrenergic vasoactive substances on tone regulation in large and small pulmonary arteries, as well as in systemic vessels of mice. We found that the beta(2)-adrenoceptor antagonist ICI 118,551 (ICI) evoked a decrease of vascular tone in large pulmonary arteries and reduced the sensitivity of pulmonary arteries toward different contracting agents, eg, norepinephrine, serotonin, or endothelin. ICI proved to act specifically on pulmonary vessels, because it shifted the dose-response curve of norepinephrine to the right in pulmonary arteries, whereas there was no effect in the aorta. Pharmacological experiments proved that the right shift of the norepinephrine dose-response curve by ICI was mediated via a beta(2)-adrenoceptor/G(i/o) protein-dependent pathway enhancing NO production in the endothelium; these results were corroborated in beta-adrenoceptor and endothelial NO synthase knockout mice where ICI had no effect. ICI increased vascular lumen diameter in lung sections and reduced pulmonary arterial pressure under normoxia and under hypoxia in the isolated perfused lung model. These effects were found to be physiologically relevant, because ICI specifically decreased pulmonary but not systemic blood pressure in vivo. Thus, the beta(2)-adrenoceptor antagonist ICI is a pulmonary arterial-specific vasorelaxant and, therefore, a potentially interesting novel therapeutic agent for the treatment of pulmonary arterial hypertension.

Evidence against vasoactive intestinal polypeptide (VIP) as a dilator and in favour of substance P as a constrictor in airway neurogenic responses.

PubMed Central

Karlsson, J. A.; Persson, C. G.

1983-01-01

Propranolol-resistant neurogenic relaxation persisted in (carbachol-contracted) guinea-pig tracheae already relaxed by supramaximal concentrations of vasoactive intestinal polypeptide (VIP). Also, VIP relaxed preparations that were under neurogenic inhibition. In hilus bronchi, about 60% of a neurogenic contraction was atropine-resistant. (Arg5, D-Trp7.9) SP 5-11 specifically antagonized this contraction and those produced by exogenous substance P. Substance P, but not VIP, seems to be involved in nerve-mediated effects on guinea-pig airway tone. PMID:6197124

Effects of vasoactive intestinal peptide and pancreatic polypeptide in rabbit intestine.

PubMed Central

Camilleri, M; Cooper, B T; Adrian, T E; Bloom, S R; Chadwick, V S

1981-01-01

The effects of porcine vasoactive intestinal peptide (VIP) and bovine pancreatic polypeptide (PP) on jejunal, ileal, and colonic fluid transport were studied in the rabbit. VIP produced secretion in the small intestine (jejunum greater than ileum) but did not affect absorption in the colon. PP had no secretory effects in jejunum, ileum, or colon. The small intestinal secretion induced by VIP was not associated with raised cAMP concentrations in the mucosa; this suggests that the secretory effects of VIP in vivo are mediated by a mechanism other than stimulation of adenylate cyclase. PMID:6257593

Tumor Blood Vessel Dynamics

NASA Astrophysics Data System (ADS)

Munn, Lance

2009-11-01

``Normalization'' of tumor blood vessels has shown promise to improve the efficacy of chemotherapeutics. In theory, anti-angiogenic drugs targeting endothelial VEGF signaling can improve vessel network structure and function, enhancing the transport of subsequent cytotoxic drugs to cancer cells. In practice, the effects are unpredictable, with varying levels of success. The predominant effects of anti-VEGF therapies are decreased vessel leakiness (hydraulic conductivity), decreased vessel diameters and pruning of the immature vessel network. It is thought that each of these can influence perfusion of the vessel network, inducing flow in regions that were previously sluggish or stagnant. Unfortunately, when anti-VEGF therapies affect vessel structure and function, the changes are dynamic and overlapping in time, and it has been difficult to identify a consistent and predictable normalization ``window'' during which perfusion and subsequent drug delivery is optimal. This is largely due to the non-linearity in the system, and the inability to distinguish the effects of decreased vessel leakiness from those due to network structural changes in clinical trials or animal studies. We have developed a mathematical model to calculate blood flow in complex tumor networks imaged by two-photon microscopy. The model incorporates the necessary and sufficient components for addressing the problem of normalization of tumor vasculature: i) lattice-Boltzmann calculations of the full flow field within the vasculature and within the tissue, ii) diffusion and convection of soluble species such as oxygen or drugs within vessels and the tissue domain, iii) distinct and spatially-resolved vessel hydraulic conductivities and permeabilities for each species, iv) erythrocyte particles advecting in the flow and delivering oxygen with real oxygen release kinetics, v) shear stress-mediated vascular remodeling. This model, guided by multi-parameter intravital imaging of tumor vessel structure and function, provides a tool for identifying the structural and functional determinants of tumor vessel normalization.

Vasoactive exposures during pregnancy and risk of microtia.

PubMed

Van Bennekom, Carla M; Mitchell, Allen A; Moore, Cynthia A; Werler, Martha M

2013-01-01

Little is known about the etiology of nonsyndromic microtia. This study investigated the hypothesis that microtia is caused by vascular disruption. The study analyzed data from the population-based National Birth Defects Prevention Study (NBDPS) for deliveries between 1997 and 2005. Four hundred eleven nonsyndromic cases of microtia, with or without additional defects, were compared to 6560 nonmalformed infants with respect to maternal exposures to vasoactive medications and smoking during the periconceptional period and conditions that have previously been associated with vascular events (multiple gestation, maternal history of type 1, type 2, or gestational diabetes, and hypertension). Odds ratios (ORs) were estimated with multivariable models, controlling for the effects of race/ethnicity, education, periconceptional folic acid use, and study center. Risk estimates for vasoactive medications and smoking were not meaningfully increased. Maternal type 1/2 diabetes was diagnosed before or during the index pregnancy in 4% and 1% of cases, respectively, compared to 1% and 0.05% of controls; the adjusted OR for these two groups combined was 7.2 (95% confidence interval [CI], 3.9-13.1). Gestational diabetes was observed for 9% of cases and 6% of controls; the OR was moderately elevated (OR, 1.4; 95% CI, 0.9-2.0). ORs were also increased for multiple gestations (OR, 2.5; 95% CI, 1.5-4.2) and pre-existing hypertension (OR, 1.6; 95% CI, 1.0-2.5). Because ORs were only elevated for diabetes and not for vasoactive exposures or other potential vascular events, findings suggest that some microtia occurrences may be part of the diabetic embryopathy rather than manifestations of vascular disruption. Birth Defects Research (Part A), 2013. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc.

46 CFR 116.300 - Structural design.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Structure § 116.300 Structural design. Except as otherwise allowed by this subpart, a vessel must comply... the vessel. (a) Steel hull vessels: (1) Rules and Regulations for the Classification of Yachts and Small Craft, Lloyd's Register of Shipping (Lloyd's); or (2) Rules for Building and Classing Steel...

46 CFR 116.300 - Structural design.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Structure § 116.300 Structural design. Except as otherwise allowed by this subpart, a vessel must comply... the vessel. (a) Steel hull vessels: (1) Rules and Regulations for the Classification of Yachts and Small Craft, Lloyd's Register of Shipping (Lloyd's); or (2) Rules for Building and Classing Steel...

46 CFR 116.300 - Structural design.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Structure § 116.300 Structural design. Except as otherwise allowed by this subpart, a vessel must comply... the vessel. (a) Steel hull vessels: (1) Rules and Regulations for the Classification of Yachts and Small Craft, Lloyd's Register of Shipping (Lloyd's); or (2) Rules for Building and Classing Steel...

46 CFR 116.300 - Structural design.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Structure § 116.300 Structural design. Except as otherwise allowed by this subpart, a vessel must comply... the vessel. (a) Steel hull vessels: (1) Rules and Regulations for the Classification of Yachts and Small Craft, Lloyd's Register of Shipping (Lloyd's); or (2) Rules for Building and Classing Steel...

46 CFR 116.300 - Structural design.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Structure § 116.300 Structural design. Except as otherwise allowed by this subpart, a vessel must comply... the vessel. (a) Steel hull vessels: (1) Rules and Regulations for the Classification of Yachts and Small Craft, Lloyd's Register of Shipping (Lloyd's); or (2) Rules for Building and Classing Steel...

Integrated head package for top mounted nuclear instrumentation

DOEpatents

Malandra, Louis J.; Hornak, Leonard P.; Meuschke, Robert E.

1993-01-01

A nuclear reactor such as a pressurized water reactor has an integrated head package providing structural support and increasing shielding leading toward the vessel head. A reactor vessel head engages the reactor vessel, and a control rod guide mechanism over the vessel head raises and lowers control rods in certain of the thimble tubes, traversing penetrations in the reactor vessel head, and being coupled to the control rods. An instrumentation tube structure includes instrumentation tubes with sensors movable into certain thimble tubes disposed in the fuel assemblies. Couplings for the sensors also traverse penetrations in the reactor vessel head. A shroud is attached over the reactor vessel head and encloses the control rod guide mechanism and at least a portion of the instrumentation tubes when retracted. The shroud forms a structural element of sufficient strength to support the vessel head, the control rod guide mechanism and the instrumentation tube structure, and includes radiation shielding material for limiting passage of radiation from retracted instrumentation tubes. The shroud is thicker at the bottom adjacent the vessel head, where the more irradiated lower ends of retracted sensors reside. The vessel head, shroud and contents thus can be removed from the reactor as a unit and rested safely and securely on a support.

[Comparison of efficacy of different neurometabolic and vasoactive medicines in ischemic stroke patients's rehabilitation].

PubMed

Galkin, A S; Koval'chuk, V V; Gusev, A O

2011-01-01

The aim of present investigation is research of influence of vasoactive and neurometabolic medicines in stroke patients's rehabilitation. We had analysed 280 stroke patients. The degree of rehabilitation had been defined with the help of Barthel and Lindmark scales. The degree of cognitive functions's rehabilitation had been defined with the help of MMSE scale. For every medicine coefficients of efficiency were calculated. As the result of the present investigation the medicine's efficiency was found out. The most efficient medicines in ischaemic stroke patients's rehabilitation among the investigated ones are the medicines which activate the neuronal metabolism, first of all,--ceraxon (citicoline).

Robust linear parameter-varying control of blood pressure using vasoactive drugs

NASA Astrophysics Data System (ADS)

Luspay, Tamas; Grigoriadis, Karolos

2015-10-01

Resuscitation of emergency care patients requires fast restoration of blood pressure to a target value to achieve hemodynamic stability and vital organ perfusion. A robust control design methodology is presented in this paper for regulating the blood pressure of hypotensive patients by means of the closed-loop administration of vasoactive drugs. To this end, a dynamic first-order delay model is utilised to describe the vasoactive drug response with varying parameters that represent intra-patient and inter-patient variability. The proposed framework consists of two components: first, an online model parameter estimation is carried out using a multiple-model extended Kalman-filter. Second, the estimated model parameters are used for continuously scheduling a robust linear parameter-varying (LPV) controller. The closed-loop behaviour is characterised by parameter-varying dynamic weights designed to regulate the mean arterial pressure to a target value. Experimental data of blood pressure response of anesthetised pigs to phenylephrine injection are used for validating the LPV blood pressure models. Simulation studies are provided to validate the online model estimation and the LPV blood pressure control using phenylephrine drug injection models representing patients showing sensitive, nominal and insensitive response to the drug.

Vasoactive drugs and the gut: is there anything new?

PubMed

Woolsey, Cheryl A; Coopersmith, Craig M

2006-04-01

Systemic changes in blood pressure and cardiac output induced by pressors and inotropes do not always correlate to improvements in regional perfusion. Since the gut is often referred to as the 'motor' of the systemic inflammatory response syndrome, the impact of vasoactive agents on splanchnic perfusion has theoretical importance. This review will highlight recent studies examining secondary effects of vasoactive agents on intestinal perfusion, metabolism, and barrier function. Norepinephrine has minimal impact on mesenteric blood flow although the combination of norepinephrine and dobutamine increases splanchnic blood flow in sepsis. Dopamine also increases mesenteric blood flow although this may be associated with negative hepatic energy balance at high does. Vasopressin and epinephrine both have negative effects on splanchnic blood flow. Newer inodilators levosimendan and olprinone preferentially improve mesenteric perfusion in animal models. Secondary effects of norepinephrine and dopamine on splanchnic perfusion are minor compared with their systemic effects. While vasopressin usage is increasing in the intensive care unit, caution should be used because of its adverse effects on gut perfusion. Experimental agents for the treatment of heart failure have beneficial gut-specific effects although the clinical significance of this is currently limited by their availability.

Exploration of the immunoreactivity of the Traditional Chinese medicine Shenrouyangzhentang to vasoactive intestinal polypeptide

PubMed Central

Gu, Yu-Chun; Chen, De-Zhen

1997-01-01

AIM: To study the immunoreactivity of the Chinese medicine Shenrouyangzhentang to vasoactive intestinal polypeptide (VIP) and its therapeutic mechanism. METHODS: The immunoreactivity of the Chinese medicine Shenrouyangzhentang to VIP was detected in the plasma of 20 normal people and 20 patients with Piyinxu (Spleen Yin deficiency) using the radioimmunoassay (RIA) method. RESULTS: The maximum binding rate B0/T was 53.29%, the non-specific binding rate N0/T was 1.170%, and the VIP standard curve was Y = 0.81983 + 0.44319X - 0.28927X2, R2 = 0.990. The VIP content in Shenrouyangzhentang was 106.6 ng/L ± 20 ng/L), while it was 90.16 ng/L ± 15 ng/L in normal human plasma and 63.25 ng/L ± 11 ng/L in the plasma of Pixinxu patients. The difference between normal plasma and Pixinxu patient plasma was statistically significant (P < 0.05). CONCLUSION: The Chinese medicine Shenrouyangzhentang demonstrated VIP immunoreactivity similar to that of normal plasma. The (vasoactive intestinal polypeptide) VIP content in Pixinxu patient plasma was lower than that in healthy subjects (P < 0.05). PMID:27041949

Conformable pressure vessel for high pressure gas storage

DOEpatents

Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

2016-01-12

A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

Recertification of the air and methane storage vessels at the Langley 8-foot high-temperature structures tunnel

NASA Technical Reports Server (NTRS)

Hudson, C. M.; Girouard, R. L.; Young, C. P., Jr.; Petley, D. H.; Hudson, J. L., Jr.; Hudgins, J. L.

1977-01-01

This center operates a number of sophisticated wind tunnels in order to fulfill the needs of its researchers. Compressed air, which is kept in steel storage vessels, is used to power many of these tunnels. Some of these vessels have been in use for many years, and Langley is currently recertifying these vessels to insure their continued structural integrity. One of the first facilities to be recertified under this program was the Langley 8-foot high-temperature structures tunnel. This recertification involved (1) modification, hydrotesting, and inspection of the vessels; (2) repair of all relevant defects; (3) comparison of the original design of the vessel with the current design criteria of Section 8, Division 2, of the 1974 ASME Boiler and Pressure Vessel Code; (4) fracture-mechanics, thermal, and wind-induced vibration analyses of the vessels; and (5) development of operating envelopes and a future inspection plan for the vessels. Following these modifications, analyses, and tests, the vessels were recertified for operation at full design pressure (41.4 MPa (6000 psi)) within the operating envelope developed.

Application of a newly built semi-submersible vessel for transportation of a tension leg platform

NASA Astrophysics Data System (ADS)

Zhang, Dagang; Sun, Weiying; Fan, Zhixia

2012-09-01

Transportation of tension leg platform (TLP) structures for a long distance has always been associated with the use of a heavy semi-transport vessel. The requirements of this type of vessel are always special, and their availability is limited. To prepare for the future development of South China Sea deepwater projects, the China Offshore Oil Engineering Corporation has recently built a heavy lift transport vessel-Hai Yang Shi You 278. This semi-submersible vessel has a displacement capacity of 50k DWT, and a breath of 42 meters. Understanding the vessel's applicability and preparing it for use in future deepwater projects are becoming imminent needs. This paper reviews the current critical issues associated with TLP transportation and performs detailed analysis of the designed TLP during load-out and transportation. The newly built COOEC transportation vessel HYSY 278 was applied to dry transport of the TLP structure from the COOEC fabrication yard in Qingdao to an oil field in South China Sea. The entire process included the load-out of the TLP structure from the landsite of the fabrication yard, the offloading and float-on of the platform from the vessel, the dry transport of the TLP over a long distance, and the final offloading of the platform. Both hydrodynamic and structure analysis were performed to evaluate the behavior of the transport vessel and TLP structure. Special attention was paid to critical areas associated with the use of this new vessel, along with any potential limitations. The results demonstrate that HYSY 278 can effectively be used for transporting the structure with proper arrangement and well-prepared operation. The procedure and details were presented on the basis of the study results. Special attention was also given to discussion on future use based on the results from the analysis.

Recent advances in lightweight, filament-wound composite pressure vessel technology

NASA Technical Reports Server (NTRS)

Lark, R. F.

1977-01-01

A review of recent advances is presented for lightweight, high performance composite pressure vessel technology that covers the areas of design concepts, fabrication procedures, applications, and performance of vessels subjected to single cycle burst and cyclic fatigue loading. Filament wound fiber/epoxy composite vessels were made from S glass, graphite, and Kevlar 49 fibers and were equipped with both structural and nonstructural liners. Pressure vessels structural efficiencies were attained which represented weight savings, using different liners, of 40 to 60 percent over all titanium pressure vessels. Significant findings in each area are summarized.

Experience of 14 years of emergency reconstruction of electrical injuries.

PubMed

Zhu, Zhi-Xiang; Xu, Xiao-Guang; Li, Wei-Ping; Wang, Dao-Xin; Zhang, Li-Yong; Chen, Li-Ying; Liu, Tian-yi

2003-02-01

Although there have been great advances in the treatment of electrical injuries in the last 20 years, the extremity loss ratio in electrical injuries remains at an unacceptably high level. The primary cause is due to the progressive tissue necrosis which results in the continuous extension of necrosis in the wound, leading to loss of the whole injured extremity. This study reports attempts to break the dangerous tissue necrosis circle and save the form and function of damaged extremities. After 14 years of systematic experimental and clinical studies a successful comprehensive urgent reconstruction alternative (CURA) for electrical injuries is proposed. CURA includes: debriding the wound as early as possible after injury; preserving the vital tissue structures as much as possible, such as nerves, vessels, joints, tendons, bone, even though they have undergone devitalization or local necrosis; repairing these vital tissues during the first surgery if functional reconstruction requires it; protecting the wound bed by covering with tissue flaps of rich blood supply; improving flap survival through moist dressings supported by continuous irrigation beneath the flaps for a 24-72h period after surgery with measures to control local infection; and last, giving general systemic treatment with vasoactive agents and antibiotics. Four hundred and fifty nine wounds in 155 patients suffering from electrical injuries have been successfully treated with this technique between 1986 and 2000 and are reported in this paper. Satisfactory results were obtained with the extremity loss proportion reduced to less than 9% compared with 41.5% during the 10 years before 1984 in the same hospital. The authors suggest that CURA is an effective and workable method for treatment of electrical injuries.

Inhibition of CD26/DPP IV attenuates ischemia/reperfusion injury in orthotopic mouse lung transplants: the pivotal role of vasoactive intestinal peptide.

PubMed

Jungraithmayr, Wolfgang; De Meester, Ingrid; Matheeussen, Veerle; Inci, Ilhan; Augustyns, Koen; Scharpé, Simon; Weder, Walter; Korom, Stephan

2010-04-01

The T cell activation Ag CD26/dipeptidylpeptidase IV (DPP IV) combines co-stimulatory and enzymatic properties. Catalytically, it functions as an exopeptidase, modulating biological activity of key chemokines and peptides. Here we investigated the effect of organ-specific inhibition of DPP IV catalytic activity on ischemia/reperfusion injury after extended ischemia in the mouse model of orthotopic single lung transplantation. C57BL/6 mice were syngeneically, transplanted, grafts were perfused and stored in Perfadex with (treated) or without (control) a DPP IV enzymatic activity inhibitor (AB192). Transplantation was performed after 18h cold ischemia time; following 2-h reperfusion, grafts were analyzed for oxygenation, thiobarbituric acid-reactive substances, histomorphology, and immunohistochemistry was performed for leukocyte Ag 6, myeloperoxidase, hemoxygenase 1, vasoactive intestinal protein (VIP), and real-time PCR for VIP. Treatment with the DPP IV inhibitor AB192 resulted in significant improvement of gas exchange, less lipid oxidation, preservation of parenchymal ultrastructure, reduced neutrophil infiltration, reduced myeloperoxidase expression, increased hemoxygenase 1 expression, pronounced expression of VIP in alveolar macrophages and increased mRNA expression of VIP. Inhibition of intragraft DPP IV catalytic activity with AB192 strikingly ameliorates ischemia/reperfusion injury after extended ischemia. Furthermore, preservation of endogenous intragraft VIP levels correlate with maintaining lung function and structural integrity. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Mast cell chymase reduces the toxicity of Gila monster venom, scorpion venom, and vasoactive intestinal polypeptide in mice

PubMed Central

Akahoshi, Mitsuteru; Song, Chang Ho; Piliponsky, Adrian M.; Metz, Martin; Guzzetta, Andrew; Åbrink, Magnus; Schlenner, Susan M.; Feyerabend, Thorsten B.; Rodewald, Hans-Reimer; Pejler, Gunnar; Tsai, Mindy; Galli, Stephen J.

2011-01-01

Mast cell degranulation is important in the pathogenesis of anaphylaxis and allergic disorders. Many animal venoms contain components that can induce mast cell degranulation, and this has been thought to contribute to the pathology and mortality caused by envenomation. However, we recently reported evidence that mast cells can enhance the resistance of mice to the venoms of certain snakes and that mouse mast cell–derived carboxypeptidase A3 (CPA3) can contribute to this effect. Here, we investigated whether mast cells can enhance resistance to the venom of the Gila monster, a toxic component of that venom (helodermin), and the structurally similar mammalian peptide, vasoactive intestinal polypeptide (VIP). Using 2 types of mast cell–deficient mice, as well as mice selectively lacking CPA3 activity or the chymase mouse mast cell protease-4 (MCPT4), we found that mast cells and MCPT4, which can degrade helodermin, can enhance host resistance to the toxicity of Gila monster venom. Mast cells and MCPT4 also can limit the toxicity associated with high concentrations of VIP and can reduce the morbidity and mortality induced by venoms from 2 species of scorpions. Our findings support the notion that mast cells can enhance innate defense by degradation of diverse animal toxins and that release of MCPT4, in addition to CPA3, can contribute to this mast cell function. PMID:21926462

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.

[Watermelon stomach: Chronic renal failure and/or imatinib?].

PubMed

Montagnac, Richard; Blaison, Dominique; Brahimi, Saïd; Schendel, Adeline; Levasseur, Thomas; Takin, Romulus

2015-11-01

Watermelon stomach or gastric antral vascular ectasia (GAVE) syndrome is an uncommon cause of sometimes severe upper gastro-intestinal bleeding. Essentially based on a pathognomonic endoscopic appearance, its diagnosis may be unrecognised because mistaken with portal hypertensive gastropathy, while treatment of these two entities is different. Its etiopathogeny remains still unclear, even if it is frequently associated with different systemic illnesses as hepatic cirrhosis, autoimmune disorders and chronic renal failure. The mechanism inducing these vascular ectasia may be linked with mechanical stress on submucosal vessels due to antropyloric peristaltic motility dysfunction modulated by neurohormonal vasoactive alterations. Because medical therapies are not very satisfactory, among the endoscopic modalities, argon plasma coagulation seems to be actually the first-line treatment because the most effective and safe. However, surgical antrectomy may be sometimes necessary. Recently GAVE syndrome appeared as a new adverse reaction of imatinib mesylate, one of the tyrosine kinase inhibitors used in chronic myeloid leukemia, and we report here the observation of such a pathology in one patient treated at the same time by haemodialysis and by imatinib mesylate for chronic myeloid leukemia. Copyright © 2015 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Pro-angiogenic cell-based therapy for the treatment of ischemic cardiovascular diseases.

PubMed

Silvestre, Jean-Sébastien

2012-10-01

Pro-angiogenic cell therapy has emerged as a promising option to treat patients with acute myocardial infarction or with critical limb ischemia. Exciting pre-clinical studies have prompted the initiation of numerous clinical trials based on administration of stem/progenitor cells with pro-angiogenic potential. Most of the clinical studies performed so far have used bone marrow-derived or peripheral blood-derived mononuclear cells and showed, overall, a modest but significant benefit on tissue remodeling and function in patients with ischemic diseases. These mixed results pave the way for the development of strategies to overcome the limitation of autologous cell therapy and to propose more efficient approaches. Such strategies include pretreatment of cells with activators to augment cell recruitment and survival in the ischemic target area and/or the improvement of cell functions such as their paracrine ability to release proangiogenic factors and vasoactive molecules. In addition, efforts should be directed towards stimulation of both angiogenesis and vessel maturation, the development of a composite product consisting of stem/progenitor cells encapsulated in a biomaterial and the use of additional sources of regenerative cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Novel Vasoactive Proline-Rich Oligopeptide from the Skin Secretion of the Frog Brachycephalus ephippium.

PubMed

Arcanjo, Daniel Dias Rufino; Vasconcelos, Andreanne Gomes; Comerma-Steffensen, Simón Gabriel; Jesus, Joilson Ramos; Silva, Luciano Paulino; Pires Júnior, Osmindo Rodrigues; Costa-Neto, Claudio Miguel; Oliveira, Eduardo Brandt; Migliolo, Ludovico; Franco, Octávio Luiz; Restini, Carolina Baraldi Araújo; Paulo, Michele; Bendhack, Lusiane Maria; Bemquerer, Marcelo Porto; Oliveira, Aldeidia Pereira; Simonsen, Ulf; Leite, José Roberto de Souza de Almeida

2015-01-01

Proline-rich oligopeptides (PROs) are a large family which comprises the bradykinin-potentiating peptides (BPPs). They inhibit the activity of the angiotensin I-converting enzyme (ACE) and have a typical pyroglutamyl (Pyr)/proline-rich structure at the N- and C-terminus, respectively. Furthermore, PROs decrease blood pressure in animals. In the present study, the isolation and biological characterization of a novel vasoactive BPP isolated from the skin secretion of the frog Brachycephalus ephippium is described. This new PRO, termed BPP-Brachy, has the primary structure WPPPKVSP and the amidated form termed BPP-BrachyNH2 inhibits efficiently ACE in rat serum. In silico molecular modeling and docking studies suggest that BPP-BrachyNH2 is capable of forming a hydrogen bond network as well as multiple van der Waals interactions with the rat ACE, which blocks the access of the substrate to the C-domain active site. Moreover, in rat thoracic aorta BPP-BrachyNH2 induces potent endothelium-dependent vasodilatation with similar magnitude as captopril. In DAF-FM DA-loaded aortic cross sections examined by confocal microscopy, BPP-BrachyNH2 was found to increase the release of nitric oxide (NO). Moreover, BPP-BrachyNH2 was devoid of toxicity in endothelial and smooth muscle cell cultures. In conclusion, the peptide BPP-BrachyNH2 has a novel sequence being the first BPP isolated from the skin secretion of the Brachycephalidae family. This opens for exploring amphibians as a source of new biomolecules. The BPP-BrachyNH2 is devoid of cytotoxicity and elicits endothelium-dependent vasodilatation mediated by NO. These findings open for the possibility of potential application of these peptides in the treatment of endothelial dysfunction and cardiovascular diseases.

A Novel Vasoactive Proline-Rich Oligopeptide from the Skin Secretion of the Frog Brachycephalus ephippium

PubMed Central

Arcanjo, Daniel Dias Rufino; Vasconcelos, Andreanne Gomes; Comerma-Steffensen, Simón Gabriel; Jesus, Joilson Ramos; Silva, Luciano Paulino; Pires, Osmindo Rodrigues; Costa-Neto, Claudio Miguel; Oliveira, Eduardo Brandt; Migliolo, Ludovico; Franco, Octávio Luiz; Restini, Carolina Baraldi Araújo; Paulo, Michele; Bendhack, Lusiane Maria; Bemquerer, Marcelo Porto; Oliveira, Aldeidia Pereira; Simonsen, Ulf; Leite, José Roberto de Souza de Almeida

2015-01-01

Proline-rich oligopeptides (PROs) are a large family which comprises the bradykinin-potentiating peptides (BPPs). They inhibit the activity of the angiotensin I-converting enzyme (ACE) and have a typical pyroglutamyl (Pyr)/proline-rich structure at the N- and C-terminus, respectively. Furthermore, PROs decrease blood pressure in animals. In the present study, the isolation and biological characterization of a novel vasoactive BPP isolated from the skin secretion of the frog Brachycephalus ephippium is described. This new PRO, termed BPP-Brachy, has the primary structure WPPPKVSP and the amidated form termed BPP-BrachyNH2 inhibits efficiently ACE in rat serum. In silico molecular modeling and docking studies suggest that BPP-BrachyNH2 is capable of forming a hydrogen bond network as well as multiple van der Waals interactions with the rat ACE, which blocks the access of the substrate to the C-domain active site. Moreover, in rat thoracic aorta BPP-BrachyNH2 induces potent endothelium-dependent vasodilatation with similar magnitude as captopril. In DAF-FM DA-loaded aortic cross sections examined by confocal microscopy, BPP-BrachyNH2 was found to increase the release of nitric oxide (NO). Moreover, BPP-BrachyNH2 was devoid of toxicity in endothelial and smooth muscle cell cultures. In conclusion, the peptide BPP-BrachyNH2 has a novel sequence being the first BPP isolated from the skin secretion of the Brachycephalidae family. This opens for exploring amphibians as a source of new biomolecules. The BPP-BrachyNH2 is devoid of cytotoxicity and elicits endothelium-dependent vasodilatation mediated by NO. These findings open for the possibility of potential application of these peptides in the treatment of endothelial dysfunction and cardiovascular diseases. PMID:26661890

Molecular Cloning and Characterization of Two Pig Vasoactive Intestinal Polypeptide Receptors (VPAC1-R and VPAC2-R)

PubMed Central

He, Xiaping; Meng, Fengyan; Wang, Yajun

2014-01-01

We here report the cloning, tissue expression, and functional analyses of the two pig vasoactive intestinal polypeptide (VIP) receptors (pVPAC1-R and pVPAC2-R). The cloned full-length pVPAC1-R and pVPAC2-R share high structural similarity with their mammalian counterparts. Functional assay revealed that the full-length pVPAC1-R and pVPAC2-R-expressed Chinese hamster ovary (CHO) cells could be activated by pVIP and pPACAP38 potently, indicating that pVPAC1-R and pVPAC2-R are capable of binding VIP and pituitary adenylate cyclase-activating polypeptide (PACAP). In addition to the identification of the transcripts encoding the two full-length receptors, multiple splice transcript variants were isolated. Comparison with the pig genome database revealed that pVPAC1-R and pVPAC2-R share a unique gene structure with 14 exons different from other vertebrates. Reverse transcription and polymerase chain reaction (RT-PCR) assays further showed that the transcript encoding the full-length pVPAC2-R is widely expressed in all adult tissues whereas the splice variants of pVPAC1-R are predominantly expressed in all tissues instead of the transcript encoding the full-length receptor, hinting that pVPAC2-R may play more important roles than pVPAC1-R in mediating VIP and PACAP actions. Our present findings help to elucidate the important role of VIP and PACAP and promote to rethink of their species-specific physiological roles including their actions in regulation of phenotypic traits in pigs. PMID:24520933

Predicting Structural Behavior of Filament Wound Composite Pressure Vessel Using Three Dimensional Shell Analysis

NASA Astrophysics Data System (ADS)

Madhavi, M.; Venkat, R.

2014-01-01

Fiber reinforced polymer composite materials with their higher specific strength, moduli and tailorability characteristics will result in reduction of weight of the structure. The composite pressure vessels with integrated end domes develop hoop stresses that are twice longitudinal stresses and when isotropic materials like metals are used for development of the hardware and the material is not fully utilized in the longitudinal/meridional direction resulting in over weight components. The determination of a proper winding angles and thickness is very important to decrease manufacturing difficulties and to increase structural efficiency. In the present study a methodology is developed to understand structural characteristics of filament wound pressure vessels with integrated end domes. Progressive ply wise failure analysis of composite pressure vessel with geodesic end domes is carried out to determine matrix crack failure, burst pressure values at various positions of the shell. A three dimensional finite element analysis is computed to predict the deformations and stresses in the composite pressure vessel. The proposed method could save the time to design filament wound structures, to check whether the ply design is safe for the given input conditions and also can be adapted to non-geodesic structures. The results can be utilized to understand structural characteristics of filament wound pressure vessels with integrated end domes. This approach can be adopted for various applications like solid rocket motor casings, automobile fuel storage tanks and chemical storage tanks. Based on the predictions a composite pressure vessel is designed and developed. Hydraulic test is performed on the composite pressure vessel till the burst pressure.

Zone-specific remodeling of tumor blood vessels affects tumor growth.

PubMed

Tilki, Derya; Kilic, Nerbil; Sevinc, Sema; Zywietz, Friedrich; Stief, Christian G; Ergun, Suleyman

2007-11-15

Chaotic organization, abnormal leakiness, and structural instability are characteristics of tumor vessels. However, morphologic events of vascular remodeling in relation to tumor growth are not sufficiently studied yet. By using the rat rhabdomyosarcoma tumor model vascular morphogenesis was studied by light and electron microscopy and immunohistochemistry in relation to tumor regions such as tumor surrounding (TSZ), marginal (TMZ), intermediate (TIZ), and center (TCZ) zones. The analyses revealed that blood vessels of TSZ display a regular ultrastructure, whereas blood vessels of TMZ showed a chaotic organization and unstable structure with a diffuse or even lacking basal lamina, and missing or irregular assembled periendothelial cells. In contrast, blood vessels of TIZ and TCZ exhibited a more or less stabilized vessel structure with increased diameter. Correspondingly, normal assembly of alpha-smooth-muscle-actin (alpha-SMA)-positive cells into the vessel wall was observed in blood vessels of TSZ, TIZ, and TCZ. Also, Ang1 immunostaining was strongest in large vessels of TIZ and TCZ, whereas Ang2 staining was prominent in small vessels of TIZ. Tie2 staining was detectable in small and large vessels of all tumor zones. Immunostaining for alpha(v)beta(3)-integrin was strongest in small vessels of TMZ, whereas large vessels of TIZ and TCZ were almost negative. The results indicate a zone-specific remodeling of tumor blood vessels by stabilization of vessels in TIZ and TCZ, whereas small vessels of these zones obviously undergo regression leading to tumor necrosis. Thus, a better understanding of vascular remodeling and stabilization in tumors would enable new strategies in tumor therapy and imaging. (c) 2007 American Cancer Society.

Hypoxic pulmonary vasodilation: a paradigm shift with a hydrogen sulfide mechanism

PubMed Central

Whitfield, Nathan L.; Bearden, Shawn E.; St. Leger, Judy; Nilson, Erika; Gao, Yan; Madden, Jane A.

2010-01-01

Hypoxic pulmonary vasoconstriction (HVC), an intrinsic and assumed ubiquitous response of mammalian pulmonary blood vessels, matches regional ventilation to perfusion via an unknown O2-sensing mechanism. Global pulmonary hypoxia experienced by individuals suffering from chronic obstructive pulmonary disease or numerous hypoventilation syndromes, including sleep apnea, often produces maladaptive pulmonary hypertension, but pulmonary hypertension is not observed in diving mammals, where profound hypoxia is routine. Here we examined the response of cow and sea lion pulmonary arteries (PA) to hypoxia and observed the expected HVC in the former and a unique hypoxic vasodilation in resistance vessels in the latter. We then used this disparate response to examine the O2-sensing mechanism. In both animals, exogenous H2S mimicked the vasoactive effects of hypoxia in isolated PA. H2S-synthesizing enzymes, cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfur transferase, were identified in lung tissue from both animals by one-dimensional Western blot analysis and immunohistochemistry. The relationship between H2S production/consumption and O2 was examined in real time by use of amperometric H2S and O2 sensors. H2S was produced by sea lion and cow lung homogenate in the absence of O2, but it was rapidly consumed when O2 was present. Furthermore, consumption of exogenous H2S by cow lung homogenate, PA smooth muscle cells, and heart mitochondria was O2 dependent and exhibited maximal sensitivity at physiologically relevant Po2 levels. These studies show that HVC is not an intrinsic property of PA and provide further evidence for O2-dependent H2S metabolism in O2 sensing. PMID:19889863

Cutaneous vasoregulation during short- and long-term aerial acclimation in the amphibious mangrove rivulus, Kryptolebias marmoratus.

PubMed

Cooper, C A; Litwiller, S L; Murrant, C L; Wright, P A

2012-03-01

The mangrove rivulus (Kryptolebias marmoratus) is an amphibious fish and evidence suggests that the cutaneous surface is the primary site of gas exchange during emersion. The aim of this study was to determine whether cutaneous blood vessels were regulated in the caudal fin during the initial transition from water to aerial exposure, and after 10 days of aerial acclimation. Acute changes (first 3 min following emersion) in the cutaneous vessels diameter were measured in real-time on live fish using light microscopy. The data show that under control conditions, only arterioles in the caudal fin were vasoactive. During the first 20s of aerial acclimation the arterioles significantly constricted (-2.1 ± 0.4 μm), which was followed immediately by a relaxation (from 40 to 180 s). This vasoconstriction was eliminated with the addition of phentolamine (50 μmoll(-1)), which indicates that the vasoconstriction was mediated by α-adrenoreceptors. Longer-term changes in the cutaneous surface vasculature were determined using fluorescent immunohistochemistry and antibodies for the endothelial marker, CD31. Fish aerially acclimated for 10 days exhibited significantly higher levels of endothelial fluorescence in the caudal fin when compared to control fish in water, indicating endothelial cell production (i.e. angiogenesis). These data combined show that for every emersion episode, there is an initial α-adrenergic mediated vasoconstriction, which is most likely, a stress response. This is then followed by a long-term acclimation involving an upregulation in endothelial cell production, which would subsequently enhance blood perfusion to the cutaneous surface and potentially increase the capacity for gas exchange with the external environment. Copyright © 2011 Elsevier Inc. All rights reserved.

[Management of cerebral small vessel disease for the diagnosis and treatment of dementia].

PubMed

Ihara, Masafumi

2013-07-01

With the demographic shift in life expectancy inexorably increasing in developed countries, dementia is set to become one of the most important health problems worldwide. In recent years, cerebral small vessel disease (SVD) has received much attention as an important cause of dementia. The reason for this is twofold: firstly, arteriosclerosis (type 1 SVD) is the leading cause of vascular cognitive impairment, and secondly, cerebral amyloid angiopathy (CAA; type 2 SVD) is an almost invariable accompaniment of Alzheimer's disease. SVD is known to induce a variety of pathological changes; for example, type 1 SVD results in lacunar infarction, deep microbleeds, and white matter damage, while type 2 SVD leads to cortical microinfarcts, lobar microbleeds, and white matter damage. SVD is considered a spectrum of abnormalities, with the majority of patients experiencing symptoms from both type 1 and type 2 SVD as the disease progresses. The discouraging results of immunotherapy clinical trials for Alzheimer's disease have shifted the scientific attention from the classical neuron-centric approach towards a novel neurovascular approach. As arteries stiffen with age or with other co-morbid factors such as life-related diseases, amyloid β (Aβ) synthesis becomes upregulated, resulting in the deposition of insoluble Aβ not only in the parenchyma as senile plaques but also in the perivascular drainage pathways as CAA. Therefore, therapeutic strategies such as vasoactive drugs that enhance the patency of this Aβ drainage pathway may facilitate Aβ removal and help prevent cognitive decline in the elderly. Based on this emerging paradigm, clinical trials are warranted to investigate whether a neurovascular therapeutic approach can effectively halt cognitive decline and act as a preemptive medicine for patients at risk of dementia.

[Substance P and vasoactive intestinal peptide in patients with progressive scleroderma. Determination of plasma level before and after autogenic training].

PubMed

Haustein, U F; Weber, B; Seikowski, K

1995-02-01

In 12 patients suffering from systemic sclerosis (SSc) the influence of autogenic training on the plasma level of the neuropeptides substance P and vasoactive intestinal peptide (VIP) was studied. Compared with healthy controls the SSc patients exhibited significantly elevated levels of substance P (mean +/- SD: 7.1 +/- 3.2 pmol/l vs 1.6 +/- 1.6 pmol/l). Apart from variations the VIP plasma concentration did not significantly differ from that in healthy controls (mean +/- SD 10.7 +/- 7.1 pmol/l versus 12.0 +/- 5.3 pmol/l). Autogenic training did not bring about any significant changes in the plasma levels of neuropeptides.

Automatic multiscale enhancement and segmentation of pulmonary vessels in CT pulmonary angiography images for CAD applications

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

Zhou Chuan; Chan, H.-P.; Sahiner, Berkman

2007-12-15

The authors are developing a computerized pulmonary vessel segmentation method for a computer-aided pulmonary embolism (PE) detection system on computed tomographic pulmonary angiography (CTPA) images. Because PE only occurs inside pulmonary arteries, an automatic and accurate segmentation of the pulmonary vessels in 3D CTPA images is an essential step for the PE CAD system. To segment the pulmonary vessels within the lung, the lung regions are first extracted using expectation-maximization (EM) analysis and morphological operations. The authors developed a 3D multiscale filtering technique to enhance the pulmonary vascular structures based on the analysis of eigenvalues of the Hessian matrix atmore » multiple scales. A new response function of the filter was designed to enhance all vascular structures including the vessel bifurcations and suppress nonvessel structures such as the lymphoid tissues surrounding the vessels. An EM estimation is then used to segment the vascular structures by extracting the high response voxels at each scale. The vessel tree is finally reconstructed by integrating the segmented vessels at all scales based on a 'connected component' analysis. Two CTPA cases containing PEs were used to evaluate the performance of the system. One of these two cases also contained pleural effusion disease. Two experienced thoracic radiologists provided the gold standard of pulmonary vessels including both arteries and veins by manually tracking the arterial tree and marking the center of the vessels using a computer graphical user interface. The accuracy of vessel tree segmentation was evaluated by the percentage of the 'gold standard' vessel center points overlapping with the segmented vessels. The results show that 96.2% (2398/2494) and 96.3% (1910/1984) of the manually marked center points in the arteries overlapped with segmented vessels for the case without and with other lung diseases. For the manually marked center points in all vessels including arteries and veins, the segmentation accuracy are 97.0% (4546/4689) and 93.8% (4439/4732) for the cases without and with other lung diseases, respectively. Because of the lack of ground truth for the vessels, in addition to quantitative evaluation of the vessel segmentation performance, visual inspection was conducted to evaluate the segmentation. The results demonstrate that vessel segmentation using our method can extract the pulmonary vessels accurately and is not degraded by PE occlusion to the vessels in these test cases.« less

Automated method for the identification and analysis of vascular tree structures in retinal vessel network

NASA Astrophysics Data System (ADS)

Joshi, Vinayak S.; Garvin, Mona K.; Reinhardt, Joseph M.; Abramoff, Michael D.

2011-03-01

Structural analysis of retinal vessel network has so far served in the diagnosis of retinopathies and systemic diseases. The retinopathies are known to affect the morphologic properties of retinal vessels such as course, shape, caliber, and tortuosity. Whether the arteries and the veins respond to these changes together or in tandem has always been a topic of discussion. However the diseases such as diabetic retinopathy and retinopathy of prematurity have been diagnosed with the morphologic changes specific either to arteries or to veins. Thus a method describing the separation of retinal vessel trees imaged in a two dimensional color fundus image may assist in artery-vein classification and quantitative assessment of morphologic changes particular to arteries or veins. We propose a method based on mathematical morphology and graph search to identify and label the retinal vessel trees, which provides a structural mapping of vessel network in terms of each individual primary vessel, its branches and spatial positions of branching and cross-over points. The method was evaluated on a dataset of 15 fundus images resulting into an accuracy of 92.87 % correctly assigned vessel pixels when compared with the manual labeling of separated vessel trees. Accordingly, the structural mapping method performs well and we are currently investigating its potential in evaluating the characteristic properties specific to arteries or veins.

[Acute myocardial infarction after wasp sting without anaphylactic reaction].

PubMed

Bongo, Angelo Sante; Fornaro, Gianluigi; Sansa, Mara; Macciò, Sergio; Rognoni, Andrea

2005-03-01

Bites of hymenopterans (bees, wasps and hornets) are very frequent phenomena that can stir up allergical reactions in venom-susceptible patients but that seldom provoke acute myocardial infarction. In the literature we can find case reports of myocardial infarction after bites of hymenopterans, and preceded by an allergic reaction (sometimes with angiographic evidence of undamaged coronary arteries). The pathophysiological determinant seems to be related to the chemical composition of hymenopterans venom, basically made up by vasoactive and thrombogenic substances able to create vasospasm and coronary thrombosis. Our report refers to a 65-year-old male patient without prior cardiological and allergic events who, bitten by a sharm of three bees, complains of an acute large anterior myocardial infarction with angiographic evidence of thrombotic lesion of the proximal left anterior descending artery treated with direct stenting with procedural success, without showing allergical symptoms. The pathophysiological determinant seems to be related to the release of vasoactive amines and thrombogenic substances contained into the hymenopterans venom, the former able to produce vasospasm, the latter able to create diffuse thrombosis. The use of adrenaline itself to counteract the possible systemic allergic reaction appears to advise against the treatment of patients with cardiological symptoms or coronary artery disease and because of its strong vasoactive activity (it leads, in fact, to vasoconstriction) and thrombogenic effects.

Recent advances in lightweight, filament-wound composite pressure vessel technology

NASA Technical Reports Server (NTRS)

Lark, R. F.

1977-01-01

A review of recent advances is presented for lightweight, high-performance composite pressure vessel technology that covers the areas of design concepts, fabrication procedures, applications, and performance of vessels subjected to single-cycle burst and cyclic fatigue loading. Filament-wound fiber/epoxy composite vessels were made from S-glass, graphite, and Kevlar 49 fibers and were equipped with both structural and nonstructural liners. Pressure vessel structural efficiencies were attained which represented weight savings, using different liners, of 40 to 60 percent over all-titanium pressure vessels. Significant findings in each area are summarized including data from current NASA-Lewis Research Center contractual and in-house programs.

Flexible Composite-Material Pressure Vessel

NASA Technical Reports Server (NTRS)

Brown, Glen; Haggard, Roy; Harris, Paul A.

2003-01-01

A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure vessels made of rigid composite materials. The vessel would be designed as a structural shell wherein the fibers would be predominantly bias-oriented, the orientations being optimized to make the fibers bear the tensile loads in the structure. Such efficient use of tension-bearing fibers would minimize or eliminate the need for stitching and fill (weft) fibers for strength. The vessel could be fabricated by techniques adapted from filament winding of prior composite-material vessels, perhaps in conjunction with the use of dry film adhesives. In addition to the high-bias main-body substructure described above, the vessel would include a low-bias end substructure to complete coverage and react peak loads. Axial elements would be overlaid to contain damage and to control fiber orientation around side openings. Fiber ring structures would be used as interfaces for connection to ancillary hardware.

Numerical investigation of hyperelastic wall deformation characteristics in a micro-scale stenotic blood vessel

NASA Astrophysics Data System (ADS)

Cheema, Taqi Ahmad; Park, Cheol Woo

2013-08-01

Stenosis is the drastic reduction of blood vessel diameter because of cholesterol accumulation in the vessel wall. In addition to the changes in blood flow characteristics, significant changes occur in the mechanical behavior of a stenotic blood vessel. We conducted a 3-D study of such behavior in micro-scale blood vessels by considering the fluid structure interaction between blood flow and vessel wall structure. The simulation consisted of one-way coupled analysis of blood flow and the resulting structural deformation without a moving mesh. A commercial code based on a finite element method with a hyperelastic material model (Neo-Hookean) of the wall was used to calculate wall deformation. Three different cases of stenosis severity and aspect ratios with and without muscles around the blood vessel were considered. The results showed that the wall deformation in a stenotic channel is directly related to stenosis severity and aspect ratio. The presence of muscles reduces the degree of deformation even in very severe stenosis.

Cerebral vessels segmentation for light-sheet microscopy image using convolutional neural networks

NASA Astrophysics Data System (ADS)

Hu, Chaoen; Hui, Hui; Wang, Shuo; Dong, Di; Liu, Xia; Yang, Xin; Tian, Jie

2017-03-01

Cerebral vessel segmentation is an important step in image analysis for brain function and brain disease studies. To extract all the cerebrovascular patterns, including arteries and capillaries, some filter-based methods are used to segment vessels. However, the design of accurate and robust vessel segmentation algorithms is still challenging, due to the variety and complexity of images, especially in cerebral blood vessel segmentation. In this work, we addressed a problem of automatic and robust segmentation of cerebral micro-vessels structures in cerebrovascular images acquired by light-sheet microscope for mouse. To segment micro-vessels in large-scale image data, we proposed a convolutional neural networks (CNNs) architecture trained by 1.58 million pixels with manual label. Three convolutional layers and one fully connected layer were used in the CNNs model. We extracted a patch of size 32x32 pixels in each acquired brain vessel image as training data set to feed into CNNs for classification. This network was trained to output the probability that the center pixel of input patch belongs to vessel structures. To build the CNNs architecture, a series of mouse brain vascular images acquired from a commercial light sheet fluorescence microscopy (LSFM) system were used for training the model. The experimental results demonstrated that our approach is a promising method for effectively segmenting micro-vessels structures in cerebrovascular images with vessel-dense, nonuniform gray-level and long-scale contrast regions.

46 CFR 176.600 - Drydock and internal structural examination intervals.

Code of Federal Regulations, 2010 CFR

2010-10-01

... States port, it must undergo the required examination before sailing. (c) If your vessel is not operated... exclusively by divers, the vessel must undergo two alternate hull exams and two internal structural exams within any five-year period. If a vessel completes a satisfactory alternate hull exam, with the...

Principle of relative positioning of structures in the human body☆

PubMed Central

Meng, Buliang; Pang, Ailan; Li, Ming

2013-01-01

The arrangement of various biological structures should generally ensure the safety of crucial structures and increase their working efficiency; however, other principles governing the relative positions of structures in humans have not been reported. The present study therefore investigated other principles using nerves and their companion vessels in the human body as an example. Nerves and blood vessels usually travel together and in the most direct way towards their targets. Human embryology, histology, and gross anatomy suggest that there are many possible positions for these structures during development. However, for mechanical reasons, tougher or stronger structures should take priority. Nerves are tougher than most other structures, followed by arteries, veins, and lymphatic vessels. Nerves should therefore follow the most direct route, and be followed by the arteries, veins, and lymphatic vessels. This general principle should be applicable to all living things. PMID:25206733

33 CFR 104.305 - Vessel Security Assessment (VSA) requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... security; (ii) Structural integrity; (iii) Personnel protection systems; (iv) Procedural policies; (v... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Vessel Security Assessment (VSA... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Assessment (VSA) § 104.305 Vessel...

33 CFR 104.305 - Vessel Security Assessment (VSA) requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... security; (ii) Structural integrity; (iii) Personnel protection systems; (iv) Procedural policies; (v... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Vessel Security Assessment (VSA... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Assessment (VSA) § 104.305 Vessel...

33 CFR 104.305 - Vessel Security Assessment (VSA) requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... security; (ii) Structural integrity; (iii) Personnel protection systems; (iv) Procedural policies; (v... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Vessel Security Assessment (VSA... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Assessment (VSA) § 104.305 Vessel...

33 CFR 104.305 - Vessel Security Assessment (VSA) requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... security; (ii) Structural integrity; (iii) Personnel protection systems; (iv) Procedural policies; (v... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Vessel Security Assessment (VSA... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Assessment (VSA) § 104.305 Vessel...

33 CFR 104.305 - Vessel Security Assessment (VSA) requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... security; (ii) Structural integrity; (iii) Personnel protection systems; (iv) Procedural policies; (v... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Vessel Security Assessment (VSA... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Assessment (VSA) § 104.305 Vessel...

In-situ structural integrity evaluation for high-power pulsed spallation neutron source - Effects of cavitation damage on structural vibration

NASA Astrophysics Data System (ADS)

Wan, Tao; Naoe, Takashi; Futakawa, Masatoshi

2016-01-01

A double-wall structure mercury target will be installed at the high-power pulsed spallation neutron source in the Japan Proton Accelerator Research Complex (J-PARC). Cavitation damage on the inner wall is an important factor governing the lifetime of the target-vessel. To monitor the structural integrity of the target vessel, displacement velocity at a point on the outer surface of the target vessel is measured using a laser Doppler vibrometer (LDV). The measured signals can be used for evaluating the damage inside the target vessel because of cyclic loading and cavitation bubble collapse caused by pulsed-beam induced pressure waves. The wavelet differential analysis (WDA) was applied to reveal the effects of the damage on vibrational cycling. To reduce the effects of noise superimposed on the vibration signals on the WDA results, analysis of variance (ANOVA) and analysis of covariance (ANCOVA), statistical methods were applied. Results from laboratory experiments, numerical simulation results with random noise added, and target vessel field data were analyzed by the WDA and the statistical methods. The analyses demonstrated that the established in-situ diagnostic technique can be used to effectively evaluate the structural response of the target vessel.

Vasoactive intestinal peptide is a local mediator in a gut-brain neural axis activating intestinal gluconeogenesis.

PubMed

De Vadder, F; Plessier, F; Gautier-Stein, A; Mithieux, G

2015-03-01

Intestinal gluconeogenesis (IGN) promotes metabolic benefits through activation of a gut-brain neural axis. However, the local mediator activating gluconeogenic genes in the enterocytes remains unknown. We show that (i) vasoactive intestinal peptide (VIP) signaling through VPAC1 receptor activates the intestinal glucose-6-phosphatase gene in vivo, (ii) the activation of IGN by propionate is counteracted by VPAC1 antagonism, and (iii) VIP-positive intrinsic neurons in the submucosal plexus are increased under the action of propionate. These data support the role of VIP as a local neuromodulator released by intrinsic enteric neurons and responsible for the induction of IGN through a VPAC1 receptor-dependent mechanism in enterocytes. © 2015 John Wiley & Sons Ltd.

Clinicopathological study of pancreatic and ganglioneuroblastoma tumours secreting vasoactive intestinal polypeptide (vipomas).

PubMed

Long, R G; Bryant, M G; Mitchell, S J; Adrian, T E; Polak, J M; Bloom, S R

1981-05-30

During a six-year period (1973-9) 52 patients with pancreatic tumours and 10 with ganglioneuroblastomas were found to have raised plasma vasoactive intestinal polypeptide (VIP) concentrations. All the patients had severe secretory diarrhoea, weight loss, dehydration, hypokalaemic acidosis, and a raised plasma urea concentration. Reduced gastric acid secretion was seen in 72% of patients. Plasma VIP concentrations were not raised in patients with diarrhoea due to other types of tumour or disease or in hormone-secreting tumours not associated with diarrhoea. Plasma VIP measurement may therefore give clinical guidance in a patient with persistent watery diarrhoea and hypokalaemic acidosis. Surgical excision was clearly the treatment of choice, but metastatic pancreatic tumours usually responded to streptozotocin.

Clinicopathological study of pancreatic and ganglioneuroblastoma tumours secreting vasoactive intestinal polypeptide (vipomas).

PubMed Central

Long, R G; Bryant, M G; Mitchell, S J; Adrian, T E; Polak, J M; Bloom, S R

1981-01-01

During a six-year period (1973-9) 52 patients with pancreatic tumours and 10 with ganglioneuroblastomas were found to have raised plasma vasoactive intestinal polypeptide (VIP) concentrations. All the patients had severe secretory diarrhoea, weight loss, dehydration, hypokalaemic acidosis, and a raised plasma urea concentration. Reduced gastric acid secretion was seen in 72% of patients. Plasma VIP concentrations were not raised in patients with diarrhoea due to other types of tumour or disease or in hormone-secreting tumours not associated with diarrhoea. Plasma VIP measurement may therefore give clinical guidance in a patient with persistent watery diarrhoea and hypokalaemic acidosis. Surgical excision was clearly the treatment of choice, but metastatic pancreatic tumours usually responded to streptozotocin. PMID:6786616

Structural Integrity of Gas-Filled Composite Overwrapped Pressure Vessels Subjected to Orbital Debris Impact

NASA Astrophysics Data System (ADS)

Telichev, Igor; Cherniaev, Aleksandr

Gas-filled pressure vessels are extensively used in spacecraft onboard systems. During operation on the orbit they exposed to the space debris environment. Due to high energies they contain, pressure vessels have been recognized as the most critical spacecraft components requiring protection from orbital debris impact. Major type of pressurized containers currently used in spacecraft onboard systems is composite overwrapped pressure vessels (COPVs) manufactured by filament winding. In the present work we analyze the structural integrity of vessels of this kind in case of orbital debris impact at velocities ranging from 2 to 10 km/s. Influence of such parameters as projectile energy, shielding standoff, internal pressure and filament winding pattern on COPVs structural integrity has been investigated by means of numerical and physical experiments.

Numerical modelling of electromagnetic loads on fusion device structures

NASA Astrophysics Data System (ADS)

Bettini, Paolo; Furno Palumbo, Maurizio; Specogna, Ruben

2014-03-01

In magnetic confinement fusion devices, during abnormal operations (disruptions) the plasma begins to move rapidly towards the vessel wall in a vertical displacement event (VDE), producing plasma current asymmetries, vessel eddy currents and open field line halo currents, each of which can exert potentially damaging forces upon the vessel and in-vessel components. This paper presents a methodology to estimate electromagnetic loads, on three-dimensional conductive structures surrounding the plasma, which arise from the interaction of halo-currents associated to VDEs with a magnetic field of the order of some Tesla needed for plasma confinement. Lorentz forces, calculated by complementary formulations, are used as constraining loads in a linear static structural analysis carried out on a detailed model of the mechanical structures of a representative machine.

Distribution of vasotocin- and vasoactive intestinal peptide-like immunoreactivity in the brain of blue tit (Cyanistes coeruleus)

PubMed Central

Montagnese, Catherine M.; Székely, Tamás; Csillag, András; Zachar, Gergely

2015-01-01

Blue tits (Cyanistes coeruleus) are songbirds, used as model animals in numerous studies covering a wide field of research. Nevertheless, the distribution of neuropeptides in the brain of this avian species remains largely unknown. Here we present some of the first results on distribution of Vasotocine (AVT) and Vasoactive intestinal peptide (VIP) in the brain of males and females of this songbird species, using immunohistochemistry mapping. The bulk of AVT-like cells are found in the hypothalamic supraoptic, paraventricular and suprachiasmatic nuclei, bed nucleus of the stria terminalis, and along the lateral forebrain bundle. Most AVT-like fibers course toward the median eminence, some reaching the arcopallium, and lateral septum. Further terminal fields occur in the dorsal thalamus, ventral tegmental area and pretectal area. Most VIP-like cells are in the lateral septal organ and arcuate nucleus. VIP-like fibers are distributed extensively in the hypothalamus, preoptic area, lateral septum, diagonal band of Broca. They are also found in the bed nucleus of the stria terminalis, amygdaloid nucleus of taenia, robust nucleus of the arcopallium, caudo-ventral hyperpallium, nucleus accumbens and the brainstem. Taken together, these results suggest that both AVT and VIP immunoreactive structures show similar distribution to other avian species, emphasizing evolutionary conservatism in the history of vertebrates. The current study may enable future investigation into the localization of AVT and VIP, in relation to behavioral and ecological traits in the brain of tit species. PMID:26236200

Relationship between retinal blood flow and arterial oxygen

PubMed Central

Cheng, Richard W.; Yusof, Firdaus; Tsui, Edmund; Jong, Monica; Duffin, James; Flanagan, John G.; Fisher, Joseph A.

2016-01-01

Key points Vascular reactivity, the response of the vessels to a vasoactive stimulus such as hypoxia and hyperoxia, can be used to assess the vascular range of adjustment in which the vessels are able to compensate for changes in PO2.Previous studies in the retina have not accurately quantified retinal vascular responses and precisely targeted multiple PaO2 stimuli at the same time as controlling the level of carbon dioxide, thus precluding them from modelling the relationship between retinal blood flow and oxygen.The present study modelled the relationship between retinal blood flow and PaO2, showing them to be a combined linear and hyperbolic function.This model demonstrates that the resting tonus of the vessels is at the mid‐point and that they have great vascular range of adjustment, compensating for decreases in oxygen above a P ETC O2 of 32–37 mmHg but being limited below this threshold. Abstract Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia) but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modelled in the retina, particularly in the vascular reserve and resting tonus of the vessels. The present study aimed to determine the limitations of the retinal vasculature by modelling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for eight different blood gas conditions, with the end‐tidal partial pressure of oxygen (P ETC O2) ranging from 40–500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon laser blood flowmeter (Canon Inc., Tokyo, Japan) during the first visit and using Doppler spectral domain optical coherence tomography during the second visit. We determined that the relationship between RBF and PaO2 can be modelled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content for all stages of hypoxia used in the present study but can no longer compensate below a P ETC O2 of 32–37 mmHg. These vessels have a great vascular range of adjustment, increasing diameter (8.5% arteriolar and 21% total venous area) with hypoxia (40 mmHg P ETC O2; P < 0.001) and decreasing diameter (6.9% arteriolar and 23% total venous area) with hyperoxia (500 mmHg P ETC O2; P < 0.001) to the same extent. This indicates that the resting tonus is near the mid‐point of the adjustment ranges at resting PaO2 where sensitivity is maximum. PMID:26607393

Relationship between retinal blood flow and arterial oxygen.

PubMed

Cheng, Richard W; Yusof, Firdaus; Tsui, Edmund; Jong, Monica; Duffin, James; Flanagan, John G; Fisher, Joseph A; Hudson, Chris

2016-02-01

Vascular reactivity, the response of the vessels to a vasoactive stimulus such as hypoxia and hyperoxia, can be used to assess the vascular range of adjustment in which the vessels are able to compensate for changes in PO2. Previous studies in the retina have not accurately quantified retinal vascular responses and precisely targeted multiple PaO2 stimuli at the same time as controlling the level of carbon dioxide, thus precluding them from modelling the relationship between retinal blood flow and oxygen. The present study modelled the relationship between retinal blood flow and PaO2, showing them to be a combined linear and hyperbolic function. This model demonstrates that the resting tonus of the vessels is at the mid-point and that they have great vascular range of adjustment, compensating for decreases in oxygen above a PETCO2 of 32-37 mmHg but being limited below this threshold. Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia) but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modelled in the retina, particularly in the vascular reserve and resting tonus of the vessels. The present study aimed to determine the limitations of the retinal vasculature by modelling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for eight different blood gas conditions, with the end-tidal partial pressure of oxygen (PETCO2) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon laser blood flowmeter (Canon Inc., Tokyo, Japan) during the first visit and using Doppler spectral domain optical coherence tomography during the second visit. We determined that the relationship between RBF and PaO2 can be modelled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content for all stages of hypoxia used in the present study but can no longer compensate below a PETCO2 of 32-37 mmHg. These vessels have a great vascular range of adjustment, increasing diameter (8.5% arteriolar and 21% total venous area) with hypoxia (40 mmHg P ETC O2; P < 0.001) and decreasing diameter (6.9% arteriolar and 23% total venous area) with hyperoxia (500 mmHg PETCO2; P < 0.001) to the same extent. This indicates that the resting tonus is near the mid-point of the adjustment ranges at resting PaO2 where sensitivity is maximum. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Could Nano-Structured Materials Enable the Improved Pressure Vessels for Deep Atmospheric Probes?

NASA Technical Reports Server (NTRS)

Srivastava, D.; Fuentes, A.; Bienstock, B.; Arnold, J. O.

2005-01-01

A viewgraph presentation on the use of Nano-Structured Materials to enable pressure vessel structures for deep atmospheric probes is shown. The topics include: 1) High Temperature/Pressure in Key X-Environments; 2) The Case for Use of Nano-Structured Materials Pressure Vessel Design; 3) Carbon based Nanomaterials; 4) Nanotube production & purification; 5) Nanomechanics of Carbon Nanotubes; 6) CNT-composites: Example (Polymer); 7) Effect of Loading sequence on Composite with 8% by volume; 8) Models for Particulate Reinforced Composites; 9) Fullerene/Ti Composite for High Strength-Insulating Layer; 10) Fullerene/Epoxy Composite for High Strength-Insulating Layer; 11) Models for Continuous Fiber Reinforced Composites; 12) Tensile Strength for Discontinuous Fiber Composite; 13) Ti + SWNT Composites: Thermal/Mechanical; 14) Ti + SWNT Composites: Tensile Strength; and 15) Nano-structured Shell for Pressure Vessels.

Automated artery-venous classification of retinal blood vessels based on structural mapping method

NASA Astrophysics Data System (ADS)

Joshi, Vinayak S.; Garvin, Mona K.; Reinhardt, Joseph M.; Abramoff, Michael D.

2012-03-01

Retinal blood vessels show morphologic modifications in response to various retinopathies. However, the specific responses exhibited by arteries and veins may provide a precise diagnostic information, i.e., a diabetic retinopathy may be detected more accurately with the venous dilatation instead of average vessel dilatation. In order to analyze the vessel type specific morphologic modifications, the classification of a vessel network into arteries and veins is required. We previously described a method for identification and separation of retinal vessel trees; i.e. structural mapping. Therefore, we propose the artery-venous classification based on structural mapping and identification of color properties prominent to the vessel types. The mean and standard deviation of each of green channel intensity and hue channel intensity are analyzed in a region of interest around each centerline pixel of a vessel. Using the vector of color properties extracted from each centerline pixel, it is classified into one of the two clusters (artery and vein), obtained by the fuzzy-C-means clustering. According to the proportion of clustered centerline pixels in a particular vessel, and utilizing the artery-venous crossing property of retinal vessels, each vessel is assigned a label of an artery or a vein. The classification results are compared with the manually annotated ground truth (gold standard). We applied the proposed method to a dataset of 15 retinal color fundus images resulting in an accuracy of 88.28% correctly classified vessel pixels. The automated classification results match well with the gold standard suggesting its potential in artery-venous classification and the respective morphology analysis.

Vesselness propagation: a fast interactive vessel segmentation method

NASA Astrophysics Data System (ADS)

Cai, Wenli; Dachille, Frank; Harris, Gordon J.; Yoshida, Hiroyuki

2006-03-01

With the rapid development of multi-detector computed tomography (MDCT), resulting in increasing temporal and spatial resolution of data sets, clinical use of computed tomographic angiography (CTA) is rapidly increasing. Analysis of vascular structures is much needed in CTA images; however, the basis of the analysis, vessel segmentation, can still be a challenging problem. In this paper, we present a fast interactive method for CTA vessel segmentation, called vesselness propagation. This method is a two-step procedure, with a pre-processing step and an interactive step. During the pre-processing step, a vesselness volume is computed by application of a CTA transfer function followed by a multi-scale Hessian filtering. At the interactive stage, the propagation is controlled interactively in terms of the priority of the vesselness. This method was used successfully in many CTA applications such as the carotid artery, coronary artery, and peripheral arteries. It takes less than one minute for a user to segment the entire vascular structure. Thus, the proposed method provides an effective way of obtaining an overview of vascular structures.

46 CFR 190.01-5 - Vessels subject to load line.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Vessels subject to load line. 190.01-5 Section 190.01-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Hull Structure § 190.01-5 Vessels subject to load line. (a) For vessels assigned a...

Development of FB-MultiPier dynamic vessel-collision analysis models, phase 2.

DOT National Transportation Integrated Search

2014-07-01

Massive waterway vessels such as barges regularly transit navigable waterways in the U.S. During passages that fall within : the vicinity of bridge structures, vessels may (under extreme circumstances) deviate from the intended vessel transit path. A...

Brain blood vessel segmentation using line-shaped profiles

NASA Astrophysics Data System (ADS)

Babin, Danilo; Pižurica, Aleksandra; De Vylder, Jonas; Vansteenkiste, Ewout; Philips, Wilfried

2013-11-01

Segmentation of cerebral blood vessels is of great importance in diagnostic and clinical applications, especially for embolization of cerebral aneurysms and arteriovenous malformations (AVMs). In order to perform embolization of the AVM, the structural and geometric information of blood vessels from 3D images is of utmost importance. For this reason, the in-depth segmentation of cerebral blood vessels is usually done as a fusion of different segmentation techniques, often requiring extensive user interaction. In this paper we introduce the idea of line-shaped profiling with an application to brain blood vessel and AVM segmentation, efficient both in terms of resolving details and in terms of computation time. Our method takes into account both local proximate and wider neighbourhood of the processed pixel, which makes it efficient for segmenting large blood vessel tree structures, as well as fine structures of the AVMs. Another advantage of our method is that it requires selection of only one parameter to perform segmentation, yielding very little user interaction.

GAS COOLED NUCLEAR REACTORS

DOEpatents

Long, E.; Rodwell, W.

1958-06-10

A gas-cooled nuclear reactor consisting of a graphite reacting core and reflector structure supported in a containing vessel is described. A gas sealing means is included for sealing between the walls of the graphite structure and containing vessel to prevent the gas coolant by-passing the reacting core. The reacting core is a multi-sided right prismatic structure having a pair of parallel slots around its periphery. The containing vessel is cylindrical and has a rib on its internal surface which supports two continuous ring shaped flexible web members with their radially innermost ends in sealing engagement within the radially outermost portion of the slots. The core structure is supported on ball bearings. This design permits thermal expansion of the core stracture and vessel while maintainirg a peripheral seal between the tvo elements.

Patch-based automatic retinal vessel segmentation in global and local structural context.

PubMed

Cao, Shuoying; Bharath, Anil A; Parker, Kim H; Ng, Jeffrey

2012-01-01

In this paper, we extend our published work [1] and propose an automated system to segment retinal vessel bed in digital fundus images with enough adaptability to analyze images from fluorescein angiography. This approach takes into account both the global and local context and enables both vessel segmentation and microvascular centreline extraction. These tools should allow researchers and clinicians to estimate and assess vessel diameter, capillary blood volume and microvascular topology for early stage disease detection, monitoring and treatment. Global vessel bed segmentation is achieved by combining phase-invariant orientation fields with neighbourhood pixel intensities in a patch-based feature vector for supervised learning. This approach is evaluated against benchmarks on the DRIVE database [2]. Local microvascular centrelines within Regions-of-Interest (ROIs) are segmented by linking the phase-invariant orientation measures with phase-selective local structure features. Our global and local structural segmentation can be used to assess both pathological structural alterations and microemboli occurrence in non-invasive clinical settings in a longitudinal study.

Octreotide Injection

MedlinePlus

... to decrease the amount of growth hormone (a natural substance) produced by people with acromegaly (condition in ... by carcinoid tumors (slow-growing tumors that release natural substances that can cause symptoms) and vasoactive intestinal ...

Watery diarrhea syndrome in an adult with ganglioneuroma-pheochromocytoma: identification of vasoactive intestinal peptide, calcitonin, and catecholamines and assessment of their biologic activity.

PubMed

Trump, D L; Livingston, J N; Baylin, S B

1977-10-01

A case of adult ganglioneuroma-pheochromocytoma with an associated watery diarrhea syndrome is reported. High levels of vasoactive intestinal peptide (VIP) were found in preoperative serum and in tumor tissue. The serum VIP levels fell to normal, and the watery diarrhae syndrome completely ceased following removal of the tumor. In addition to containing VIP, the tumor was rich in catecholamines, and calcitonin. Peptide hormone-containing extracts and catecholamine extracts from the tumor both activated the adenyl cyclase system and increased lipolytic activity in a preparation of isolated rat fat cells. The findings in this patient further link VIP with neural crest tissues, and suggest the importance of determining catecholamine levels in patients with the watery diarrhea syndrome.

Evidence for circulatory benefits of resveratrol in humans.

PubMed

Wong, Rachel H X; Coates, Alison M; Buckley, Jonathan D; Howe, Peter R C

2013-07-01

Impairments of endothelial function, which can be assessed noninvasively by flow-mediated dilation (FMD) of the brachial artery, contribute to the development of cardiovascular disease. Associations between FMD and cognition suggest a vascular component in the loss of cognitive function. Certain vasoactive nutrients that have been shown to improve FMD may also have the potential to enhance cerebral perfusion and cognition. Preclinical studies show that trans-resveratrol can enhance nitric oxide bioavailability, thereby increasing endothelium-dependent vasodilation. We have now shown that acute administration of resveratrol elicits dose-dependent increases of FMD with greater potency than other vasoactive nutrients and that this benefit is sustained following regular consumption. We describe the potential implications of this vasodilator benefit of resveratrol and its role in enhancing cerebrovascular and cognitive functions. © 2013 New York Academy of Sciences.

Tissue heterogeneity in structure and conductivity contribute to cell survival during irreversible electroporation ablation by “electric field sinks”

PubMed Central

Golberg, Alexander; Bruinsma, Bote G.; Uygun, Basak E.; Yarmush, Martin L.

2015-01-01

Irreversible electroporation (IRE) is an emerging, minimally invasive technique for solid tumors ablation, under clinical investigation for cancer therapy. IRE affects only the cell membrane, killing cells while preserving the extracellular matrix structure. Current reports indicate tumors recurrence rate after IRE averaging 31% of the cases, of which 10% are local recurrences. The mechanisms for these recurrences are not known and new explanations for incomplete cell death are needed. Using finite elements method for electric field distribution, we show that presence of vascular structures with blood leads to the redistribution of electric fields leading to the areas with more than 60% reduced electric field strength in proximity to large blood vessels and clustered vessel structures. In an in vivo rat model of liver IRE ablation, we show that cells located in the proximity of larger vessel structures and in proximity of clustered vessel structures appear less affected by IRE ablation than cells in the tissue parenchyma or in the proximity of small, more isolated vessels. These findings suggest a role for “electric field sinks” in local tumors recurrences after IRE and emphasize the importance of the precise mapping of the targeted organ structure and conductivity for planning of electroporation procedures. PMID:25684630

Tissue heterogeneity in structure and conductivity contribute to cell survival during irreversible electroporation ablation by "electric field sinks".

PubMed

Golberg, Alexander; Bruinsma, Bote G; Uygun, Basak E; Yarmush, Martin L

2015-02-16

Irreversible electroporation (IRE) is an emerging, minimally invasive technique for solid tumors ablation, under clinical investigation for cancer therapy. IRE affects only the cell membrane, killing cells while preserving the extracellular matrix structure. Current reports indicate tumors recurrence rate after IRE averaging 31% of the cases, of which 10% are local recurrences. The mechanisms for these recurrences are not known and new explanations for incomplete cell death are needed. Using finite elements method for electric field distribution, we show that presence of vascular structures with blood leads to the redistribution of electric fields leading to the areas with more than 60% reduced electric field strength in proximity to large blood vessels and clustered vessel structures. In an in vivo rat model of liver IRE ablation, we show that cells located in the proximity of larger vessel structures and in proximity of clustered vessel structures appear less affected by IRE ablation than cells in the tissue parenchyma or in the proximity of small, more isolated vessels. These findings suggest a role for "electric field sinks" in local tumors recurrences after IRE and emphasize the importance of the precise mapping of the targeted organ structure and conductivity for planning of electroporation procedures.

Segmentation of hepatic artery in multi-phase liver CT using directional dilation and connectivity analysis

NASA Astrophysics Data System (ADS)

Wang, Lei; Schnurr, Alena-Kathrin; Zidowitz, Stephan; Georgii, Joachim; Zhao, Yue; Razavi, Mohammad; Schwier, Michael; Hahn, Horst K.; Hansen, Christian

2016-03-01

Segmentation of hepatic arteries in multi-phase computed tomography (CT) images is indispensable in liver surgery planning. During image acquisition, the hepatic artery is enhanced by the injection of contrast agent. The enhanced signals are often not stably acquired due to non-optimal contrast timing. Other vascular structure, such as hepatic vein or portal vein, can be enhanced as well in the arterial phase, which can adversely affect the segmentation results. Furthermore, the arteries might suffer from partial volume effects due to their small diameter. To overcome these difficulties, we propose a framework for robust hepatic artery segmentation requiring a minimal amount of user interaction. First, an efficient multi-scale Hessian-based vesselness filter is applied on the artery phase CT image, aiming to enhance vessel structures with specified diameter range. Second, the vesselness response is processed using a Bayesian classifier to identify the most probable vessel structures. Considering the vesselness filter normally performs not ideally on the vessel bifurcations or the segments corrupted by noise, two vessel-reconnection techniques are proposed. The first technique uses a directional morphological operator to dilate vessel segments along their centerline directions, attempting to fill the gap between broken vascular segments. The second technique analyzes the connectivity of vessel segments and reconnects disconnected segments and branches. Finally, a 3D vessel tree is reconstructed. The algorithm has been evaluated using 18 CT images of the liver. To quantitatively measure the similarities between segmented and reference vessel trees, the skeleton coverage and mean symmetric distance are calculated to quantify the agreement between reference and segmented vessel skeletons, resulting in an average of 0:55+/-0:27 and 12:7+/-7:9 mm (mean standard deviation), respectively.

Human Vascular Microphysiological System for in vitro Drug Screening.

PubMed

Fernandez, C E; Yen, R W; Perez, S M; Bedell, H W; Povsic, T J; Reichert, W M; Truskey, G A

2016-02-18

In vitro human tissue engineered human blood vessels (TEBV) that exhibit vasoactivity can be used to test human toxicity of pharmaceutical drug candidates prior to pre-clinical animal studies. TEBVs with 400-800 μM diameters were made by embedding human neonatal dermal fibroblasts or human bone marrow-derived mesenchymal stem cells in dense collagen gel. TEBVs were mechanically strong enough to allow endothelialization and perfusion at physiological shear stresses within 3 hours after fabrication. After 1 week of perfusion, TEBVs exhibited endothelial release of nitric oxide, phenylephrine-induced vasoconstriction, and acetylcholine-induced vasodilation, all of which were maintained up to 5 weeks in culture. Vasodilation was blocked with the addition of the nitric oxide synthase inhibitor L-N(G)-Nitroarginine methyl ester (L-NAME). TEBVs elicited reversible activation to acute inflammatory stimulation by TNF-α which had a transient effect upon acetylcholine-induced relaxation, and exhibited dose-dependent vasodilation in response to caffeine and theophylline. Treatment of TEBVs with 1 μM lovastatin for three days prior to addition of Tumor necrosis factor - α (TNF-α) blocked the injury response and maintained vasodilation. These results indicate the potential to develop a rapidly-producible, endothelialized TEBV for microphysiological systems capable of producing physiological responses to both pharmaceutical and immunological stimuli.

Cerebral Microvascular and Systemic Effects Following Intravenous Administration of the Perfluorocarbon Emulsion Perftoran

PubMed Central

Abutarboush, Rania; Saha, Biswajit K.; Mullah, Saad H.; Arnaud, Francoise G.; Haque, Ashraful; Aligbe, Chioma; Pappas, Georgina; Auker, Charles R.; McCarron, Richard M.; Moon-Massat, Paula F.; Scultetus, Anke H.

2016-01-01

Oxygen-carrying perfluorocarbon (PFC) fluids have the potential to increase tissue oxygenation during hypoxic states and to reduce ischemic cell death. Regulatory approval of oxygen therapeutics was halted due to concerns over vasoconstrictive side effects. The goal of this study was to assess the potential vasoactive properties of Perftoran by measuring brain pial arteriolar diameters in a healthy rat model. Perftoran, crystalloid (saline) or colloid (Hextend) solutions were administered as four sequential 30 min intravenous (IV) infusions, thus allowing an evaluation of cumulative dose-dependent effects. There were no overall changes in diameters of small-sized (<50 μm) pial arterioles within the Perftoran group, while both saline and Hextend groups exhibited vasoconstriction. Medium-sized arterioles (50–100 μm) showed minor (~8–9%) vasoconstriction within saline and Hextend groups and only ~5% vasoconstriction within the Perftoran group. For small- and medium-sized pial arterioles, the mean percent change in vessel diameters was not different among the groups. Although there was a tendency for arterial blood pressures to increase with Perftoran, pressures were not different from the other two groups. These data show that Perftoran, when administered to healthy anesthetized rats, does not cause additional vasoconstriction in cerebral pial arterioles or increase systemic blood pressure compared with saline or Hextend. PMID:27869709

Cerebral Microvascular and Systemic Effects Following Intravenous Administration of the Perfluorocarbon Emulsion Perftoran.

PubMed

Abutarboush, Rania; Saha, Biswajit K; Mullah, Saad H; Arnaud, Francoise G; Haque, Ashraful; Aligbe, Chioma; Pappas, Georgina; Auker, Charles R; McCarron, Richard M; Moon-Massat, Paula F; Scultetus, Anke H

2016-11-18

Oxygen-carrying perfluorocarbon (PFC) fluids have the potential to increase tissue oxygenation during hypoxic states and to reduce ischemic cell death. Regulatory approval of oxygen therapeutics was halted due to concerns over vasoconstrictive side effects. The goal of this study was to assess the potential vasoactive properties of Perftoran by measuring brain pial arteriolar diameters in a healthy rat model. Perftoran, crystalloid (saline) or colloid (Hextend) solutions were administered as four sequential 30 min intravenous (IV) infusions, thus allowing an evaluation of cumulative dose-dependent effects. There were no overall changes in diameters of small-sized (<50 μm) pial arterioles within the Perftoran group, while both saline and Hextend groups exhibited vasoconstriction. Medium-sized arterioles (50-100 μm) showed minor (~8-9%) vasoconstriction within saline and Hextend groups and only ~5% vasoconstriction within the Perftoran group. For small- and medium-sized pial arterioles, the mean percent change in vessel diameters was not different among the groups. Although there was a tendency for arterial blood pressures to increase with Perftoran, pressures were not different from the other two groups. These data show that Perftoran, when administered to healthy anesthetized rats, does not cause additional vasoconstriction in cerebral pial arterioles or increase systemic blood pressure compared with saline or Hextend.

Successful Implantation of Bioengineered, Intrinsically Innervated, Human Internal Anal Sphincter

PubMed Central

Raghavan, Shreya; Gilmont, Robert R.; Miyasaka, Eiichi A.; Somara, Sita; Srinivasan, Shanthi; Teitelbaum, Daniel H; Bitar, Khalil N.

2011-01-01

Background & Aims To restore fecal continence, the weakened pressure of the internal anal sphincter (IAS) must be increased. We bioengineered intrinsically innervated human IAS, to emulate sphincteric physiology, in vitro. Methods We co-cultured human IAS circular smooth muscle with immortomouse fetal enteric neurons. We investigated the ability of bioengineered innervated human IAS, implanted in RAG1−/− mice, to undergo neovascularization and preserve the physiology of the constituent myogenic and neuronal components. Results The implanted IAS was neovascularized in vivo; numerous blood vessels were observed with no signs of inflammation or infection. Real-time force acquisition from implanted and pre-implant IAS showed distinct characteristics of IAS physiology. Features included the development of spontaneous myogenic basal tone; relaxation of 100% of basal tone in response to inhibitory neurotransmitter vasoactive intestinal peptide (VIP) and direct electrical field stimulation of the intrinsic innervation; inhibition of nitrergic and VIPergic EFS-induced relaxation (by antagonizing nitric oxide synthesis or receptor interaction); contraction in response to cholinergic stimulation with acetylcholine; and intact electromechanical coupling (evidenced by direct response to potassium chloride). Implanted, intrinsically innervated bioengineered human IAS tissue preserved the integrity and physiology of myogenic and neuronal components. Conclusion Intrinsically innervated human IAS bioengineered tissue can be successfully implanted in mice. This approach might be used to treat patients with fecal incontinence. PMID:21463628

Bronchial mucosal immunoreactivity of sensory neuropeptides in severe airway diseases.

PubMed

Chanez, P; Springall, D; Vignola, A M; Moradoghi-Hattvani, A; Polak, J M; Godard, P; Bousquet, J

1998-09-01

Neuropeptides act on most of the components of the bronchial environment. They influence bronchomotor tone and bronchial vascular caliber and permeability. To investigate the nonadrenergic, noncholinergic system within the airways in asthma and chronic bronchitis, we performed endobronchial biopsies in 16 normal human volunteers, 49 patients with asthma of varying severity, including 16 patients treated with oral corticosteroids, and 13 patients with chronic bronchitis. Frozen sections of biopsies stained with specific antibodies against the neural marker PGP 9.5, vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), and neuropeptide Y (NPY) were analyzed for the presence of nerves through indirect immunofluorescence. Nerves were present in most of the biopsies and were found within and below the epithelium and adjacent to smooth muscle, glands, and blood vessels. By comparison with those in normal subjects, the numbers of VIP-immunoreactive nerves were not significantly decreased in patients with asthma and chronic bronchitis, but NPY-immunoreactive nerves were significantly decreased in the smooth muscle of these latter two groups of patients (p < 0.005). There was no correlation between disease severity and the number of nerves found in the biopsies. This study does not confirm previous findings in autopsy material of some defects in sensory and VIP-containing nerves in severe asthma.

[Changes in prescription patterns for peripheral and cerebral vasoactive drugs before and after establishing prescription standards in France].

PubMed

Vuittenez, F; Guignard, E; Comte, S

1999-01-23

Assess changes in the number of prescriptions for peripheral and cerebral vasoactive drugs for the treatment of lower limb arteritis and cerebrovascular disease since the promulgation in 1995 of prescription standards for the treatment of lower limb arteritis. Assess compliance to prescription standards with a detailed analysis of patient features, prescriptions written for lower limb arteritis, cerebrovascular disease and concomitant diseases and evaluate changes in treatment costs for lower limb arteritis and cerebrovascular disease as well as cost of the full prescription, including treatments for associated diseases. This study was based on data recorded during the Permanent Study of Medical Prescriptions conducted from March 1994 to February 1995 and from March 1995 to February 1996 by the IMS. Prescription costs were established from the National Description Files of the IMS. Treatment costs were expressed as public price (FF) tax included. Prescriptions meeting the following criteria were selected for each period: prescriptions written by general practitioners for drugs with peripheral and cerebral vasoactivity (excepting calcium antagonists with a cerebral target) belonging to the Anatomic Therapeutic Classes C4A1 of the European Pharmaceutical Marketing Research Association, Bromly 1996; prescriptions for diagnoses 447.6 (arteritis) and 437.9 (cerebrovascular disease) according to the 9th WHO classification. A random sample of 500 prescriptions was selected to calculate costs. Since the advent of the prescription standards in 1995, prescriptions have dropped off by 6.3% for lower limb arteritis and by 14.8% for cerebrovascular disease. There was a 3.7 point decline in the percentage of multiple prescriptions of vasoactive drugs for lower limb arteritis (21.7% prior to March 1995 versus 18% after promulgation of the prescription standards, p > 0.1) and a 1.8 increase in the percentage of multiple prescriptions for cerebrovascular disease (14% prior to March 1995 and 15.8% after promulgation of the prescription standards, p > 0.1). For the treatment of lower limb arteritis, prescription costs fell by a mean 9% per prescription and for the treatment of cerebrovascular disease they rose by a mean 7% per prescription. The price rise, due to multiple prescriptions of vasoactive drugs was 190 FF per prescription for lower limb arteritis and 104 FF per prescription for cerebrovascular disease. Despite the retrospective nature of this study where confounding factors could not be controlled, our findings are in agreement with those reported earlier suggesting that cost containment policy implemented by the prescription standards has had little efficacy. In patients with arterial disease of the lower limbs, the percentage of prescriptions not complying with the recommended standards decreased by one-third to one-half over a 2-year period since the prescription standards were first announced in 1994.

Allergies and Headache

MedlinePlus

... headache continues to be controversial. Many patients with migraine headache attribute their reactions to certain foods as ... majority of foods that play a role in migraine contain vasoactive or neuroactive amino acids such as ...

Vasoactive intestinal peptide test

MedlinePlus

... found in cells in the nervous system and gut. VIP has many functions, including relaxing certain muscles, triggering release of hormones from the pancreas, gut, and hypothalamus, and increasing the amount of water ...

Roi Detection and Vessel Segmentation in Retinal Image

NASA Astrophysics Data System (ADS)

Sabaz, F.; Atila, U.

2017-11-01

Diabetes disrupts work by affecting the structure of the eye and afterwards leads to loss of vision. Depending on the stage of disease that called diabetic retinopathy, there are sudden loss of vision and blurred vision problems. Automated detection of vessels in retinal images is a useful study to diagnose eye diseases, disease classification and other clinical trials. The shape and structure of the vessels give information about the severity of the disease and the stage of the disease. Automatic and fast detection of vessels allows for a quick diagnosis of the disease and the treatment process to start shortly. ROI detection and vessel extraction methods for retinal image are mentioned in this study. It is shown that the Frangi filter used in image processing can be successfully used in detection and extraction of vessels.

Relation of pulmonary vessel size to transfer factor in subjects with airflow obstruction

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

Musk, A.W.

In a group of 61 consecutive patients undergoing assessment of airflow obstruction, a significant linear relation was demonstrated between measurements of the diameter of the midzonal pulmonary vessels on the plain chest radiographs and transfer factor (diffusing capacity for carbon monoxide) (r = 0.46, p < 0.001). Since reduction in transfer factor has been shown to relate to structural emphysema, reduction in midzone vessel caliber implies the same. However, in the individual patient neither the transfer factor nor structural emphysema can be reliably predicted from midzone vessel diameters alone.

Vascular depression consensus report - a critical update.

PubMed

Aizenstein, Howard J; Baskys, Andrius; Boldrini, Maura; Butters, Meryl A; Diniz, Breno S; Jaiswal, Manoj Kumar; Jellinger, Kurt A; Kruglov, Lev S; Meshandin, Ivan A; Mijajlovic, Milija D; Niklewski, Guenter; Pospos, Sarah; Raju, Keerthy; Richter, Kneginja; Steffens, David C; Taylor, Warren D; Tene, Oren

2016-11-03

Vascular depression is regarded as a subtype of late-life depression characterized by a distinct clinical presentation and an association with cerebrovascular damage. Although the term is commonly used in research settings, widely accepted diagnostic criteria are lacking and vascular depression is absent from formal psychiatric manuals such as the Diagnostic and Statistical Manual of Mental Disorders, 5 th edition - a fact that limits its use in clinical settings. Magnetic resonance imaging (MRI) techniques, showing a variety of cerebrovascular lesions, including extensive white matter hyperintensities, subcortical microvascular lesions, lacunes, and microinfarcts, in patients with late life depression, led to the introduction of the term "MRI-defined vascular depression". This diagnosis, based on clinical and MRI findings, suggests that vascular lesions lead to depression by disruption of frontal-subcortical-limbic networks involved in mood regulation. However, despite multiple MRI approaches to shed light on the spatiotemporal structural changes associated with late life depression, the causal relationship between brain changes, related lesions, and late life depression remains controversial. While postmortem studies of elderly persons who died from suicide revealed lacunes, small vessel, and Alzheimer-related pathologies, recent autopsy data challenged the role of these lesions in the pathogenesis of vascular depression. Current data propose that the vascular depression connotation should be reserved for depressed older patients with vascular pathology and evident cerebral involvement. Based on current knowledge, the correlations between intra vitam neuroimaging findings and their postmortem validity as well as the role of peripheral markers of vascular disease in late life depression are discussed. The multifold pathogenesis of vascular depression as a possible subtype of late life depression needs further elucidation. There is a need for correlative clinical, intra vitam structural and functional MRI as well as postmortem MRI and neuropathological studies in order to confirm the relationship between clinical symptomatology and changes in specific brain regions related to depression. To elucidate the causal relationship between regional vascular brain changes and vascular depression, animal models could be helpful. Current treatment options include a combination of vasoactive drugs and antidepressants, but the outcomes are still unsatisfying.

Tubular inverse opal scaffolds for biomimetic vessels

NASA Astrophysics Data System (ADS)

Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

2016-07-01

There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03173k

Rotating plug bearing and seal

DOEpatents

Wade, Elman E.

1977-01-01

A bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing.

46 CFR 177.330 - Sailing vessels.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Sailing vessels. 177.330 Section 177.330 Shipping COAST...) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.330 Sailing vessels. The design, materials, and construction of masts, posts, yards, booms, bowsprits, and standing rigging on a sailing vessel must be suitable...

46 CFR 177.330 - Sailing vessels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Sailing vessels. 177.330 Section 177.330 Shipping COAST...) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.330 Sailing vessels. The design, materials, and construction of masts, posts, yards, booms, bowsprits, and standing rigging on a sailing vessel must be suitable...

46 CFR 116.330 - Sailing vessels.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Sailing vessels. 116.330 Section 116.330 Shipping COAST... Structure § 116.330 Sailing vessels. The design, materials, and construction of masts, posts, yards, booms, bowsprits, and standing rigging on a sailing vessel must be suitable for the intended service. The hull...

46 CFR 116.330 - Sailing vessels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Sailing vessels. 116.330 Section 116.330 Shipping COAST... Structure § 116.330 Sailing vessels. The design, materials, and construction of masts, posts, yards, booms, bowsprits, and standing rigging on a sailing vessel must be suitable for the intended service. The hull...

43 CFR 423.38 - Operating vessels on Reclamation waters.

Code of Federal Regulations, 2011 CFR

2011-10-01

... official. (i) You must not attach or anchor a vessel to structures such as locks, dams, regulatory or navigational buoys, or other structures not designed for such purpose. (j) You must display an international...

43 CFR 423.38 - Operating vessels on Reclamation waters.

Code of Federal Regulations, 2010 CFR

2010-10-01

... official. (i) You must not attach or anchor a vessel to structures such as locks, dams, regulatory or navigational buoys, or other structures not designed for such purpose. (j) You must display an international...

The structural characteristics and expression of neuropeptides in the esophagus of patients with congenital esophageal atresia and tracheoesophageal fistula.

PubMed

Li, Kai; Zheng, Shan; Xiao, Xianmin; Wang, Qihong; Zhou, Yiming; Chen, Lian

2007-08-01

The aim of this study was to investigate the structural characteristics and the expression of a group of neuropeptides in the esophagus of patients with congenital esophageal atresia and tracheoesophageal fistula (EA-TEF), as well to elucidate the roles of these neuropeptides in the pathogenesis of postoperative incoordination of esophagus after successful surgical repair of EA-TEF. Twenty-four specimens from distal tracheoesophageal fistulas of patients with EA-TEF (EA-TEF group) and 10 esophageal specimens from neonates who died of nonesophageal diseases (control group) were studied. All of the specimens were subjected to routine pathologic study, ultrastructural observation, and immunohistochemical staining for neuron-specific enolase, substance P, vasoactive intestinal polypeptide, and nitric oxide synthase. In the EA-TEF group, mitochondria were distributed along the membrane of smooth muscle cell, whereas mitochondria in the control group were distributed along the karyotheca of the smooth muscle cells. The ratio of granulated vesicles to clear vesicles in the varicosity of the intramuscular motor nerve ending of the EA-TEF group (0.520 +/- 0.137) was much higher than that in the control group (0.192 +/- 0.020, P < .05). The percentages of specimens shown to have positive expression of neuron-specific enolase and substance P in the EA-TEF group (20.8% and 12.5%, respectively) were significantly lower than those in the control group (90% and 80% respectively, P < .05). The percentages of specimens shown to have positive expression of vasoactive intestinal polypeptide and nitric oxide synthase in the EA-TEF group (83.3% and 75%, respectively) were significantly higher than that in the control group (30% and 10% respectively, P < .05). Imbalance of neurotransmitters excretion in nerve vesicle, abnormal intrinsic dysplasia of nerve plexus and increased expression of certain neuropeptides were the main characteristics of esophagus with abnormal intrinsic innervation, which may be responsible for the postoperative esophageal dysfunction of EA-TEF.

46 CFR 177.300 - Structural design.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.300 Structural design. Except as otherwise allowed by this... (incorporated by reference, see 46 CFR 175.600); (b) Steel hull vessels: (1) Lloyd's Yachts and Small Craft; or (2) ABS Steel Vessel Rules (< 61 Meters)(incorporated by reference, see 46 CFR 175.600); (c) Fiber...

46 CFR 177.300 - Structural design.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.300 Structural design. Except as otherwise allowed by this... (incorporated by reference, see 46 CFR 175.600); (b) Steel hull vessels: (1) Lloyd's Yachts and Small Craft; or (2) ABS Steel Vessel Rules (<61 Meters)(incorporated by reference, see 46 CFR 175.600); (c) Fiber...

46 CFR 177.300 - Structural design.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.300 Structural design. Except as otherwise allowed by this... (incorporated by reference, see 46 CFR 175.600); (b) Steel hull vessels: (1) Lloyd's Yachts and Small Craft; or (2) ABS Steel Vessel Rules (<61 Meters)(incorporated by reference, see 46 CFR 175.600); (c) Fiber...

46 CFR 177.300 - Structural design.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.300 Structural design. Except as otherwise allowed by this... (incorporated by reference, see 46 CFR 175.600); (b) Steel hull vessels: (1) Lloyd's Yachts and Small Craft; or (2) ABS Steel Vessel Rules (< 61 Meters)(incorporated by reference, see 46 CFR 175.600); (c) Fiber...

46 CFR 177.300 - Structural design.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.300 Structural design. Except as otherwise allowed by this... (incorporated by reference, see 46 CFR 175.600); (b) Steel hull vessels: (1) Lloyd's Yachts and Small Craft; or (2) ABS Steel Vessel Rules (< 61 Meters)(incorporated by reference, see 46 CFR 175.600); (c) Fiber...

Calcitonin

MedlinePlus

... Cancer Therapy Glucose Tests Gonorrhea Testing Gram Stain Growth Hormone Haptoglobin hCG Pregnancy hCG Tumor Marker HDL Cholesterol ... pancreatic tumors called VIPomas (associated with vasoactive intestinal peptide (VIP) hormone production). Concentrations of calcitonin may be increased with ...

TUNING IMMUNE TOLERANCE WITH VASOACTIVE INTESTINAL PEPTIDE: A NEW THERAPEUTIC APPROACH FOR IMMUNE DISORDERS

PubMed Central

POZO, DAVID; GONZALEZ-REY, ELENA; CHORNY, ALEJO; ANDERSON, PER; VARELA, NIEVES; DELGADO, MARIO

2007-01-01

The induction of immune tolerance is essential for the maintenance of immune homeostasis and to limit the occurrence of exacerbated inflammatory and autoimmune conditions. Multiple mechanisms act together to ensure self-tolerance, including central clonal deletion, cytokine deviation and induction of regulatory T cells. Identifying the factors that regulate these processes is crucial for the development of new therapies of autoimmune diseases and transplantation. The vasoactive intestinal peptide (VIP) is a well-characterized endogenous anti-inflammatory neuropeptide with therapeutic potential for a variety of immune disorders. Here we examine the latest research findings, which indicate that VIP participates in maintaining immune tolerance in two distinct ways: by regulating the balance between pro-inflammatory and anti-inflammatory factors, and by inducing the emergence of regulatory T cells with suppressive activity against autoreactive T-cell effectors. PMID:17521775

Clostridium difficile suppresses colonic vasoactive intestinal peptide associated with altered motility.

PubMed

Nassif, A; Longo, W E; Sexe, R; Stratton, M; Standeven, J; Vernava, A M; Kaminski, D L

1995-01-01

We investigated whether Clostridium difficile toxin alters colonic tissue levels of vasoactive intestinal peptide (VIP) at the expense of changes in colonic motility in the isolated perfused rabbit left colon. Colonic inflammation was induced by the intracolonic administration of 10(-8) M C. difflcile toxin. Strain gauge transducers were sewn onto the serosal surface of the colon to evaluate colonic motility. C. difflcile administration produced histologic changes consistent with epithelial damage. This was associated with an increased production of prostaglandin E(2) and thromboxane B(2). Tissue levels of VIP but not substance P were significantly reduced. This was associated with an increased number of contractions per minute and an average force of each colonic contraction. These results suggest that tissue levels of VIP are suppressed by C. difflcile and may participate in colonic dysmotility during active inflammation.

In-hospital pediatric cardiac arrest in Spain.

PubMed

López-Herce, Jesús; del Castillo, Jimena; Cañadas, Sonia; Rodríguez-Núñez, Antonio; Carrillo, Angel

2014-03-01

The objective was to analyze the characteristics and prognostic factors of in-hospital pediatric cardiac arrest in Spain. A prospective observational study was performed to examine in-hospital pediatric cardiac arrest. Two hundred children were studied, aged between 1 month and 18 years, with in-hospital cardiac arrest. Univariate and multivariate logistic regression analyses were performed to assess the influence of each factor on survival to hospital discharge. Return of spontaneous circulation was achieved in 74% of the patients and 41% survived to hospital discharge. The survival rate was significantly higher than that reported in a previous Spanish study 10 years earlier (25.9%). In the univariate analysis, the factors related to mortality were body weight higher than 10 kg; continuous infusion of vasoactive drugs prior to cardiac arrest; sepsis and neurological disorders as causes of cardiac arrest, the need for treatment with adrenaline, bicarbonate, and volume expansion, and prolonged cardiopulmonary resuscitation. In the multivariate analysis, the factors related to mortality were hematologic/oncologic diseases, continuous infusion of vasoactive drugs prior to cardiac arrest, cardiopulmonary resuscitation for more than 20 min, and treatment with bicarbonate and volume expansion. Survival after in-hospital cardiac arrest in children has significantly improved in recent years. The factors related to in-hospital mortality were hematologic/oncologic diseases, continuous infusion of vasoactive drugs prior to cardiac arrest, the duration of cardiopulmonary resuscitation, and treatment with bicarbonate and volume expansion. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

Optimization study on structural analyses for the J-PARC mercury target vessel

NASA Astrophysics Data System (ADS)

Guan, Wenhai; Wakai, Eiichi; Naoe, Takashi; Kogawa, Hiroyuki; Wakui, Takashi; Haga, Katsuhiro; Takada, Hiroshi; Futakawa, Masatoshi

2018-06-01

The spallation neutron source at the Japan Proton Accelerator Research Complex (J-PARC) mercury target vessel is used for various materials science studies, work is underway to achieve stable operation at 1 MW. This is very important for enhancing the structural integrity and durability of the target vessel, which is being developed for 1 MW operation. In the present study, to reduce thermal stress and relax stress concentrations more effectively in the existing target vessel in J-PARC, an optimization approach called the Taguchi method (TM) is applied to thermo-mechanical analysis. The ribs and their relative parameters, as well as the thickness of the mercury vessel and shrouds, were selected as important design parameters for this investigation. According to the analytical results of 18 model types designed using the TM, the optimal design was determined. It is characterized by discrete ribs and a thicker vessel wall than the current design. The maximum thermal stresses in the mercury vessel and the outer shroud were reduced by 14% and 15%, respectively. Furthermore, it was indicated that variations in rib width, left/right rib intervals, and shroud thickness could influence the maximum thermal stress performance. It is therefore concluded that the TM was useful for optimizing the structure of the target vessel and to reduce the thermal stress in a small number of calculation cases.

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.

The topography, architecture and structure of the enteric nervous system in the jejunum and ileum of cattle

PubMed Central

BALEMBA, O. B.; MBASSA, G. K.; SEMUGURUKA, W. D.; ASSEY, R. J.; KAHWA, C. K. B.; HAY-SCHMIDT, A.; DANTZER, V.

1999-01-01

To date, there appear to have been no detailed and clear descriptions of the nerve plexuses and their subdivisions in the intestine of cattle. In this study, the enteric nervous system in the jejunum and ileum of 12 1-y-old calves was examined using neurofilament protein and vasoactive intestinal peptide immunohistochemistry in wholemounts and paraffin sections combined with staining of paraffin and historesin sections with haematoxylin and eosin. The main organisation of the plexuses was similar to that of the pig, horse and man with external and internal submucous plexuses being morphologically distinct, with further subdivisions of the internal submucous plexus into the external and internal subplexuses. However, in contrast to pig, horse and man, the submucous layer was firmly attached to the inner circular muscle layer. The myenteric plexus was well developed with large ganglia, and primary and secondary nerve strands. Its main axis was oriented parallel to the outer longitudinal smooth muscle; large ganglia and primary nerve strands fused to form complex ganglia, and 2 types of tertiary nerve strands were observed. Antibodies to neurofilament proteins and vasoactive intestinal peptide revealed adendritic, pseudouniaxonal or multiaxonal type II neurons only in the myenteric and submucous plexuses. This appears to be the first report of the identification of isolated uniaxonal, multidendritic type IV neurons in the mucous pericryptal plexus. The new information presented here provides further evidence for the existence of anatomical and functional differences between the external and internal submucous plexuses and for supporting the nomenclature proposed earlier. PMID:10473287

46 CFR 42.13-5 - Strength of vessel.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Strength of vessel. 42.13-5 Section 42.13-5 Shipping... General Rules for Determining Load Lines § 42.13-5 Strength of vessel. (a) The assigning and issuing authority shall satisfy itself that the general structural strength of the vessel is sufficient for the...

Mass Spectrometry and Antibody-Based Characterization of Blood Vessels from Brachylophosaurus canadensis

PubMed Central

Cleland, Timothy P.; Schroeter, Elena R.; Zamdborg, Leonid; Zheng, Wenxia; Lee, Ji Eun; Tran, John C.; Bern, Marshall; Duncan, Michael B.; Lebleu, Valerie S.; Ahlf, Dorothy R.; Thomas, Paul M.; Kalluri, Raghu; Kelleher, Neil L.; Schweitzer, Mary H.

2016-01-01

Structures similar to blood vessels in location, morphology, flexibility, and transparency have been recovered after demineralization of multiple dinosaur cortical bone fragments from multiple specimens, some of which are as old as 80 Ma. These structures were hypothesized to be either endogenous to the bone (i.e., of vascular origin) or the result of biofilm colonizing the empty osteonal network after degradation of original organic components. Here, we test the hypothesis that these structures are endogenous and thus retain proteins in common with extant archosaur blood vessels that can be detected with high-resolution mass spectrometry and confirmed by immunofluorescence. Two lines of evidence support this hypothesis. First, peptide sequencing of Brachylophosaurus canadensis blood vessel extracts is consistent with peptides comprising extant archosaurian blood vessels and is not consistent with a bacterial, cellular slime mold, or fungal origin. Second, proteins identified by mass spectrometry can be localized to the tissues using antibodies specific to these proteins, validating their identity. Data are available via ProteomeXchange with identifier PXD001738. PMID:26595531

Tubular inverse opal scaffolds for biomimetic vessels.

PubMed

Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

2016-07-14

There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.

Mass Spectrometry and Antibody-Based Characterization of Blood Vessels from Brachylophosaurus canadensis.

PubMed

Cleland, Timothy P; Schroeter, Elena R; Zamdborg, Leonid; Zheng, Wenxia; Lee, Ji Eun; Tran, John C; Bern, Marshall; Duncan, Michael B; Lebleu, Valerie S; Ahlf, Dorothy R; Thomas, Paul M; Kalluri, Raghu; Kelleher, Neil L; Schweitzer, Mary H

2015-12-04

Structures similar to blood vessels in location, morphology, flexibility, and transparency have been recovered after demineralization of multiple dinosaur cortical bone fragments from multiple specimens, some of which are as old as 80 Ma. These structures were hypothesized to be either endogenous to the bone (i.e., of vascular origin) or the result of biofilm colonizing the empty osteonal network after degradation of original organic components. Here, we test the hypothesis that these structures are endogenous and thus retain proteins in common with extant archosaur blood vessels that can be detected with high-resolution mass spectrometry and confirmed by immunofluorescence. Two lines of evidence support this hypothesis. First, peptide sequencing of Brachylophosaurus canadensis blood vessel extracts is consistent with peptides comprising extant archosaurian blood vessels and is not consistent with a bacterial, cellular slime mold, or fungal origin. Second, proteins identified by mass spectrometry can be localized to the tissues using antibodies specific to these proteins, validating their identity. Data are available via ProteomeXchange with identifier PXD001738.

Beyond Frangi: an improved multiscale vesselness filter

NASA Astrophysics Data System (ADS)

Jerman, Tim; Pernuš, Franjo; Likar, Boštjan; Špiclin, Žiga

2015-03-01

Vascular diseases are among the top three causes of death in the developed countries. Effective diagnosis of vascular pathologies from angiographic images is therefore very important and usually relies on segmentation and visualization of vascular structures. To enhance the vascular structures prior to their segmentation and visualization, and to suppress non-vascular structures and image noise, the filters enhancing vascular structures are used extensively. Even though several enhancement filters are widely used, the responses of these filters are typically not uniform between vessels of different radii and, compared to the response in the central part of vessels, their response is lower at vessels' edges and bifurcations, and vascular pathologies like aneurysm. In this paper, we propose a novel enhancement filter based on ratio of multiscale Hessian eigenvalues, which yields a close-to-uniform response in all vascular structures and accurately enhances the border between the vascular structures and the background. The proposed and four state-of-the-art enhancement filters were evaluated and compared on a 3D synthetic image containing tubular structures and a clinical dataset of 15 cerebral 3D digitally subtracted angiograms with manual expert segmentations. The evaluation was based on quantitative metrics of segmentation performance, computed as area under the precision-recall curve, signal-to-noise ratio of the vessel enhancement and the response uniformity within vascular structures. The proposed filter achieved the best scores in all three metrics and thus has a high potential to further improve the performance of existing or encourage the development of more advanced methods for segmentation and visualization of vascular structures.

The Pig Olfactory Brain: A Primer

PubMed Central

Feldman, Sanford; Osterberg, Stephen K.

2016-01-01

Despite the fact that pigs are reputed to have excellent olfactory abilities, few studies have examined regions of the pig brain involved in the sense of smell. The present study provides an overview of the olfactory bulb, anterior olfactory nucleus, and piriform cortex of adult pigs using several approaches. Nissl, myelin, and Golgi stains were used to produce a general overview of the organization of the regions and confocal microscopy was employed to examine 1) projection neurons, 2) GABAergic local circuit neurons that express somatostatin, parvalbumin, vasoactive intestinal polypeptide, or calretinin, 3) neuromodulatory fibers (cholinergic and serotonergic), and 4) glia (astrocytes and microglia). The findings revealed that pig olfactory structures are quite large, highly organized and follow the general patterns observed in mammals. PMID:26936231

The prospect of modern thermomechanics in structural integrity calculations of large-scale pressure vessels

NASA Astrophysics Data System (ADS)

Fekete, Tamás

2018-05-01

Structural integrity calculations play a crucial role in designing large-scale pressure vessels. Used in the electric power generation industry, these kinds of vessels undergo extensive safety analyses and certification procedures before deemed feasible for future long-term operation. The calculations are nowadays directed and supported by international standards and guides based on state-of-the-art results of applied research and technical development. However, their ability to predict a vessel's behavior under accidental circumstances after long-term operation is largely limited by the strong dependence of the analysis methodology on empirical models that are correlated to the behavior of structural materials and their changes during material aging. Recently a new scientific engineering paradigm, structural integrity has been developing that is essentially a synergistic collaboration between a number of scientific and engineering disciplines, modeling, experiments and numerics. Although the application of the structural integrity paradigm highly contributed to improving the accuracy of safety evaluations of large-scale pressure vessels, the predictive power of the analysis methodology has not yet improved significantly. This is due to the fact that already existing structural integrity calculation methodologies are based on the widespread and commonly accepted 'traditional' engineering thermal stress approach, which is essentially based on the weakly coupled model of thermomechanics and fracture mechanics. Recently, a research has been initiated in MTA EK with the aim to review and evaluate current methodologies and models applied in structural integrity calculations, including their scope of validity. The research intends to come to a better understanding of the physical problems that are inherently present in the pool of structural integrity problems of reactor pressure vessels, and to ultimately find a theoretical framework that could serve as a well-grounded theoretical foundation for a new modeling framework of structural integrity. This paper presents the first findings of the research project.

Tumor vessel normalization by the PI3K inhibitor HS-173 enhances drug delivery.

PubMed

Kim, Soo Jung; Jung, Kyung Hee; Son, Mi Kwon; Park, Jung Hee; Yan, Hong Hua; Fang, Zhenghuan; Kang, Yeo Wool; Han, Boreum; Lim, Joo Han; Hong, Soon-Sun

2017-09-10

Tumor vessels are leaky and immature, which causes poor oxygen and nutrient supply to tumor vessels and results in cancer cell metastasis to distant organs. This instability of tumor blood vessels also makes it difficult for anticancer drugs to penetrate and reach tumors. Numerous tumor vessel normalization approaches have been investigated for improving drug delivery into tumors. In this study, we investigated whether phosphoinositide 3-kinase (PI3K) inhibitors are able to improve vascular structure and function over the prolonged period necessary to achieve effective vessel normalization. The PI3K inhibitors, HS-173 and BEZ235 potently suppressed tumor growth and hypoxia, and increased tumor apoptosis in animal models. PI3K inhibitors also induced a regular, flat monolayer of endothelial cells (ECs) in vessels, improving stability of vessel structure, and normalized tumor vessels by increasing vascular maturity, pericyte coverage, basement membrane thickness, and tight-junctions. These effects resulted in a decrease in tumor vessel tortuosity and vessel thinning, and improved vessel function and blood flow. The tumor vessel stabilization effect of the PI3K inhibitor HS-173 also decreased the number of metastatic lung nodules in vivo metastasis model. Furthermore, HS-173 improved the delivery of doxorubicin into the tumor region, enhancing its anticancer effects. Mechanistic studies suggested that PI3K inhibitor HS-173-induced vessel normalization reflected changes in endothelial Notch signaling. Taken together, our findings indicate that vessel normalization by PI3K inhibitors restrained tumor growth and metastasis while improving chemotherapy by enhancing drug delivery into the tumor, suggesting that HS-173 may have a therapeutic value as an enhancer or an anticancer drug. Copyright © 2017 Elsevier B.V. All rights reserved.

Secondary flow vortical structures in a 180∘ elastic curved vessel with torsion under steady and pulsatile inflow conditions

NASA Astrophysics Data System (ADS)

Najjari, Mohammad Reza; Plesniak, Michael W.

2018-01-01

Secondary flow structures in a 180∘ curved pipe model of an artery are studied using particle image velocimetry. Both steady and pulsatile inflow conditions are investigated. In planar curved pipes with steady flow, multiple (two, four, six) vortices are detected. For pulsatile flow, various pairs of vortices, i.e., Dean, deformed-Dean, Lyne-type, and split-Dean, are present in the cross section of the pipe at 90∘ into the bend. The effects of nonplanar curvature (torsion) and vessel dilatation on these vortical structures are studied. Torsion distorts the symmetric secondary flows (which exist in planar curvatures) and can result in formation of more complex vortical structures. For example, the split-Dean and Lyne-type vortices with same rotation direction originating from opposite sides of the cross section tend to merge together in pulsatile flow. The vortical structures in elastic vessels with dilatation (0.61%-3.23%) are also investigated and the results are compared with rigid model results. It was found that the secondary flow structures in rigid and elastic models are similar, and hence the local compliance of the vessel does not affect the morphology of secondary flow structures.

Patient-specific computational modeling of blood flow in the pulmonary arterial circulation.

PubMed

Kheyfets, Vitaly O; Rios, Lourdes; Smith, Triston; Schroeder, Theodore; Mueller, Jeffrey; Murali, Srinivas; Lasorda, David; Zikos, Anthony; Spotti, Jennifer; Reilly, John J; Finol, Ender A

2015-07-01

Computational fluid dynamics (CFD) modeling of the pulmonary vasculature has the potential to reveal continuum metrics associated with the hemodynamic stress acting on the vascular endothelium. It is widely accepted that the endothelium responds to flow-induced stress by releasing vasoactive substances that can dilate and constrict blood vessels locally. The objectives of this study are to examine the extent of patient specificity required to obtain a significant association of CFD output metrics and clinical measures in models of the pulmonary arterial circulation, and to evaluate the potential correlation of wall shear stress (WSS) with established metrics indicative of right ventricular (RV) afterload in pulmonary hypertension (PH). Right Heart Catheterization (RHC) hemodynamic data and contrast-enhanced computed tomography (CT) imaging were retrospectively acquired for 10 PH patients and processed to simulate blood flow in the pulmonary arteries. While conducting CFD modeling of the reconstructed patient-specific vasculatures, we experimented with three different outflow boundary conditions to investigate the potential for using computationally derived spatially averaged wall shear stress (SAWSS) as a metric of RV afterload. SAWSS was correlated with both pulmonary vascular resistance (PVR) (R(2)=0.77, P<0.05) and arterial compliance (C) (R(2)=0.63, P<0.05), but the extent of the correlation was affected by the degree of patient specificity incorporated in the fluid flow boundary conditions. We found that decreasing the distal PVR alters the flow distribution and changes the local velocity profile in the distal vessels, thereby increasing the local WSS. Nevertheless, implementing generic outflow boundary conditions still resulted in statistically significant SAWSS correlations with respect to both metrics of RV afterload, suggesting that the CFD model could be executed without the need for complex outflow boundary conditions that require invasively obtained patient-specific data. A preliminary study investigating the relationship between outlet diameter and flow distribution in the pulmonary tree offers a potential computationally inexpensive alternative to pressure based outflow boundary conditions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Fetal Growth Restriction Induces Heterogeneous Effects on Vascular Biomechanical and Functional Properties in Guinea Pigs (Cavia porcellus)

PubMed Central

Cañas, Daniel; Herrera, Emilio A.; García-Herrera, Claudio; Celentano, Diego; Krause, Bernardo J.

2017-01-01

Aim: Fetal growth restriction (FGR) is associated with a variety of cardiometabolic diseases in adulthood which could involve remodeling processes of the vascular walls that could start in the fetal period. However, there is no consensus whether this remodeling affects in a similar way the whole vascular system. We aimed to determine the effects of FGR on the vasoactive and biomechanical properties of umbilical and systemic vessels in fetal guinea pigs. Methods: FGR was induced by implanting ameroid occluders at mid-gestation in uterine arteries of pregnant guinea pigs, whilst the control group was exposed to simulated surgery. At the term of gestation, systemic arteries (aorta, carotid and femoral) and umbilical vessels were isolated to determine ex vivo contractile and biomechanical responses (stretch-stress until rupture) on a wire myograph, as well as opening angle and residual stresses. Histological characteristics in tissue samples were measured by van Gieson staining. Results: Aorta and femoral arteries from FGR showed an increased in biomechanical markers of stiffness (p < 0.01), contractile capacity (p < 0.05) and relative media thickness (p < 0.01), but a reduced internal diameter (p < 0.001), compared with controls. There were no differences in the biomechanical properties of carotid and umbilical from control and FGR fetuses, but FGR umbilical arteries had a decreased contractile response to KCl (p < 0.05) along with a reduced relative media thickness (p < 0.05). Conclusion: Altogether, these changes in functional, mechanical and morphological properties suggest that FGR is associated with a heterogeneous pro-constrictive vascular remodeling affecting mainly the lower body fetal arteries. These effects would be set during a pathologic pregnancy in order to sustain the fetal blood redistribution in the FGR and may persist up to adulthood increasing the risk of a cardiovascular disease. PMID:28344561

Atherosclerotic plaque rupture and thrombosis. Evolving concepts.

PubMed

Fuster, V; Stein, B; Ambrose, J A; Badimon, L; Badimon, J J; Chesebro, J H

1990-09-01

Rupture of an atherosclerotic plaque associated with partial or complete thrombotic vessel occlusion is fundamental to the development of ischemic coronary syndromes. Plaques that produce only mild-to-moderate angiographic luminal stenosis are frequently those that undergo abrupt disruption, leading to unstable angina or acute myocardial infarction. Plaques with increased lipid content appear more prone to rupture, particularly when the lipid pool is localized eccentrically within the intima. Macrophages appear to play an important role in atherogenesis, perhaps by participating in the uptake and metabolism of lipoproteins, secretion of growth factors, and production of enzymes and toxic metabolites that may facilitate plaque rupture. In addition, the particular composition or configuration of a plaque and the hemodynamic forces to which it is exposed may determine its susceptibility to disruption. Exposure of collagen, lipids, and smooth muscle cells after plaque rupture leads to the activation of platelets and the coagulation cascade system. The resulting thrombus may lead to marked reduction in myocardial perfusion and the development of an unstable coronary syndrome, or it may become organized and incorporated into the diseased vessel, thus contributing to the progression of atherosclerosis. In unstable angina, plaque disruption leads to thrombosis, which is usually labile and results in only a transient reduction in myocardial perfusion. Release of vasoactive substances, arterial spasm, or increases in myocardial oxygen demand may contribute to ischemia. In acute myocardial infarction, plaque disruption results in a more persistent thrombotic vessel occlusion; the extent of necrosis depends on the size of the artery, the duration of occlusion, the presence of collateral flow, and the integrity of the fibrinolytic system. Thrombi that undergo lysis expose a highly thrombogenic surface to the circulating blood, which has the capacity of activating platelets and the coagulation cascade system and may lead to thrombotic reocclusion. Measurements aimed at reversing the process of atherosclerosis via cholesterol reduction and enhanced high density lipoprotein activity are encouraging. Active research is being focused on the development of new antithrombotic tools, such as inhibitors of thrombin, thromboxane, and serotonin receptor antagonists, and monoclonal antibodies aimed at blocking platelet membrane receptors or adhesive proteins. These compounds may prove useful when immediate and potent inhibition of the hemostatic system is desired. Intensive research is still needed in the areas of pathogenesis and therapeutic intervention in atherosclerosis.

Effect of blood vessels on light distribution in optogenetic stimulation of cortex.

PubMed

Azimipour, Mehdi; Atry, Farid; Pashaie, Ramin

2015-05-15

In this Letter, the impact of blood vessels on light distribution during photostimulation of cortical tissue in small rodents is investigated. Brain optical properties were extracted using a double-integrating sphere setup, and optical coherence tomography was used to image cortical vessels and capillaries to generate a three-dimensional angiogram of the cortex. By combining these two datasets, a complete volumetric structure of the cortical tissue was developed and linked to a Monte Carlo code which simulates light propagation in this inhomogeneous structure and illustrates the effect of blood vessels on the penetration depth and pattern preservation in optogenetic stimulation.

Boiling water reactor radiation shielded Control Rod Drive Housing Supports

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

Baversten, B.; Linden, M.J.

1995-03-01

The Control Rod Drive (CRD) mechanisms are located in the area below the reactor vessel in a Boiling Water Reactor (BWR). Specifically, these CRDs are located between the bottom of the reactor vessel and above an interlocking structure of steel bars and rods, herein identified as CRD Housing Supports. The CRD Housing Supports are designed to limit the travel of a Control Rod and Control Rod Drive in the event that the CRD vessel attachement went to fail, allowing the CRD to be ejected from the vessel. By limiting the travel of the ejected CRD, the supports prevent a nuclearmore » overpower excursion that could occur as a result of the ejected CRD. The Housing Support structure must be disassembled in order to remove CRDs for replacement or maintenance. The disassembly task can require a significant amount of outage time and personnel radiation exposure dependent on the number and location of the CRDs to be changed out. This paper presents a way to minimize personal radiation exposure through the re-design of the Housing Support structure. The following paragraphs also delineate a method of avoiding the awkward, manual, handling of the structure under the reactor vessel during a CRD change out.« less

Tall fescue ergot alkaloids are vasoactive in equine vasculature

USDA-ARS?s Scientific Manuscript database

Mares grazing endophyte-infected (Epichloë coenophiala) tall fescue (Lolium arundinaceum) typically exhibit reproductive dysfunction rather than problems associated with peripheral vasoconstriction as a primary sign of the fescue toxicosis syndrome. Research using Doppler ultrasonography demonstrate...

Frog secretions and hunting magic in the upper Amazon: identification of a peptide that interacts with an adenosine receptor.

PubMed Central

Daly, J W; Caceres, J; Moni, R W; Gusovsky, F; Moos, M; Seamon, K B; Milton, K; Myers, C W

1992-01-01

A frog used for "hunting magic" by several groups of Panoan-speaking Indians in the borderline between Brazil and Peru is identified as Phyllomedusa bicolor. This frog's skin secretion, which the Indians introduce into the body through fresh burns, is rich in peptides. These include vasoactive peptides, opioid peptides, and a peptide that we have named adenoregulin, with the sequence GLWSKIKEVGKEAAKAAAKAAGKAALGAVSEAV as determined from mass spectrometry and Edman degradation. The natural peptide may contain a D amino acid residue, since it is not identical in chromatographic properties to the synthetic peptide. Adenoregulin enhances binding of agonists to A1 adenosine receptors; it is accompanied in the skin secretion by peptides that inhibit binding. The vasoactive peptide sauvagine, the opioid peptides, and adenoregulin and related peptides affect behavior in mice and presumably contribute to the behavioral sequelae observed in humans. Images PMID:1438301

Frog secretions and hunting magic in the upper Amazon: identification of a peptide that interacts with an adenosine receptor.

PubMed

Daly, J W; Caceres, J; Moni, R W; Gusovsky, F; Moos, M; Seamon, K B; Milton, K; Myers, C W

1992-11-15

A frog used for "hunting magic" by several groups of Panoan-speaking Indians in the borderline between Brazil and Peru is identified as Phyllomedusa bicolor. This frog's skin secretion, which the Indians introduce into the body through fresh burns, is rich in peptides. These include vasoactive peptides, opioid peptides, and a peptide that we have named adenoregulin, with the sequence GLWSKIKEVGKEAAKAAAKAAGKAALGAVSEAV as determined from mass spectrometry and Edman degradation. The natural peptide may contain a D amino acid residue, since it is not identical in chromatographic properties to the synthetic peptide. Adenoregulin enhances binding of agonists to A1 adenosine receptors; it is accompanied in the skin secretion by peptides that inhibit binding. The vasoactive peptide sauvagine, the opioid peptides, and adenoregulin and related peptides affect behavior in mice and presumably contribute to the behavioral sequelae observed in humans.

Methylene blue, midodrine, and pseudoephedrine: a review of alternative agents for refractory hypotension in the intensive care unit.

PubMed

Van Berkel, Megan A; Fuller, Laura A; Alexandrov, Anne W; Jones, G Morgan

2015-01-01

Hypotensive episodes are common among patients in the intensive care unit and can lead to multiorgan failure if uncontrolled. Fluid administration and continuous infusion of vasoactive agents are frequently used for management of hypotension; however, both therapies may be associated with adverse effects including pulmonary edema and tissue necrosis. In addition, availability of these first-line agents has been impacted by the increasing occurrence of drug shortages. Methylene blue, pseudoephedrine, and midodrine have been considered potential alternatives to standard therapy. These agents may not only be used when first-line agents are unavailable due to shortages, but they may also aid in reducing the cumulative dose of other vasoactive agents used. The purpose of this review was to discuss strategies for the safe and effective use of methylene blue, pseudoephedrine, and midodrine for the treatment of hypotension in the critically ill.

Clostridium difficile suppresses colonic vasoactive intestinal peptide associated with altered motility

PubMed Central

Nassif, A.; Sexe, R.; Stratton, M.; Standeven, J.; Vernava, A. M.; Kaminski, D. L.

1995-01-01

We investigated whether Clostridium difficile toxin alters colonic tissue levels of vasoactive intestinal peptide (VIP) at the expense of changes in colonic motility in the isolated perfused rabbit left colon. Colonic inflammation was induced by the intracolonic administration of 10−8 M C. difflcile toxin. Strain gauge transducers were sewn onto the serosal surface of the colon to evaluate colonic motility. C. difflcile administration produced histologic changes consistent with epithelial damage. This was associated with an increased production of prostaglandin E2 and thromboxane B2. Tissue levels of VIP but not substance P were significantly reduced. This was associated with an increased number of contractions per minute and an average force of each colonic contraction. These results suggest that tissue levels of VIP are suppressed by C. difflcile and may participate in colonic dysmotility during active inflammation. PMID:18475679

Retinal blood vessel extraction using tunable bandpass filter and fuzzy conditional entropy.

PubMed

Sil Kar, Sudeshna; Maity, Santi P

2016-09-01

Extraction of blood vessels on retinal images plays a significant role for screening of different opthalmologic diseases. However, accurate extraction of the entire and individual type of vessel silhouette from the noisy images with poorly illuminated background is a complicated task. To this aim, an integrated system design platform is suggested in this work for vessel extraction using a sequential bandpass filter followed by fuzzy conditional entropy maximization on matched filter response. At first noise is eliminated from the image under consideration through curvelet based denoising. To include the fine details and the relatively less thick vessel structures, the image is passed through a bank of sequential bandpass filter structure optimized for contrast enhancement. Fuzzy conditional entropy on matched filter response is then maximized to find the set of multiple optimal thresholds to extract the different types of vessel silhouettes from the background. Differential Evolution algorithm is used to determine the optimal gain in bandpass filter and the combination of the fuzzy parameters. Using the multiple thresholds, retinal image is classified as the thick, the medium and the thin vessels including neovascularization. Performance evaluated on different publicly available retinal image databases shows that the proposed method is very efficient in identifying the diverse types of vessels. Proposed method is also efficient in extracting the abnormal and the thin blood vessels in pathological retinal images. The average values of true positive rate, false positive rate and accuracy offered by the method is 76.32%, 1.99% and 96.28%, respectively for the DRIVE database and 72.82%, 2.6% and 96.16%, respectively for the STARE database. Simulation results demonstrate that the proposed method outperforms the existing methods in detecting the various types of vessels and the neovascularization structures. The combination of curvelet transform and tunable bandpass filter is found to be very much effective in edge enhancement whereas fuzzy conditional entropy efficiently distinguishes vessels of different widths. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Fast vessel segmentation in retinal images using multi-scale enhancement and second-order local entropy

NASA Astrophysics Data System (ADS)

Yu, H.; Barriga, S.; Agurto, C.; Zamora, G.; Bauman, W.; Soliz, P.

2012-03-01

Retinal vasculature is one of the most important anatomical structures in digital retinal photographs. Accurate segmentation of retinal blood vessels is an essential task in automated analysis of retinopathy. This paper presents a new and effective vessel segmentation algorithm that features computational simplicity and fast implementation. This method uses morphological pre-processing to decrease the disturbance of bright structures and lesions before vessel extraction. Next, a vessel probability map is generated by computing the eigenvalues of the second derivatives of Gaussian filtered image at multiple scales. Then, the second order local entropy thresholding is applied to segment the vessel map. Lastly, a rule-based decision step, which measures the geometric shape difference between vessels and lesions is applied to reduce false positives. The algorithm is evaluated on the low-resolution DRIVE and STARE databases and the publicly available high-resolution image database from Friedrich-Alexander University Erlangen-Nuremberg, Germany). The proposed method achieved comparable performance to state of the art unsupervised vessel segmentation methods with a competitive faster speed on the DRIVE and STARE databases. For the high resolution fundus image database, the proposed algorithm outperforms an existing approach both on performance and speed. The efficiency and robustness make the blood vessel segmentation method described here suitable for broad application in automated analysis of retinal images.

33 CFR Appendix I to Subpart A of... - Vessel Dimensions

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Vessel Dimensions I Appendix I to... Subpart A of Part 401—Vessel Dimensions Structures are located at a number of Seaway locks which, when... of 23.2 m. For vessels that have a beam width less than this and that have dimensions exceeding the...

33 CFR Appendix I to Subpart A of... - Vessel Dimensions

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Vessel Dimensions I Appendix I to... Subpart A of Part 401—Vessel Dimensions Structures are located at a number of Seaway locks which, when... of 23.2 m. For vessels that have a beam width less than this and that have dimensions exceeding the...

33 CFR Appendix I to Subpart A of... - Vessel Dimensions

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Vessel Dimensions I Appendix I to... Subpart A of Part 401—Vessel Dimensions Structures are located at a number of Seaway locks which, when... of 23.2 m. For vessels that have a beam width less than this and that have dimensions exceeding the...

33 CFR Appendix I to Subpart A of... - Vessel Dimensions

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Vessel Dimensions I Appendix I to... Subpart A of Part 401—Vessel Dimensions Structures are located at a number of Seaway locks which, when... of 23.2 m. For vessels that have a beam width less than this and that have dimensions exceeding the...

33 CFR Appendix I to Subpart A of... - Vessel Dimensions

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Vessel Dimensions I Appendix I to... Subpart A of Part 401—Vessel Dimensions Structures are located at a number of Seaway locks which, when... of 23.2 m. For vessels that have a beam width less than this and that have dimensions exceeding the...

A Morphological Hessian Based Approach for Retinal Blood Vessels Segmentation and Denoising Using Region Based Otsu Thresholding

PubMed Central

BahadarKhan, Khan; A Khaliq, Amir; Shahid, Muhammad

2016-01-01

Diabetic Retinopathy (DR) harm retinal blood vessels in the eye causing visual deficiency. The appearance and structure of blood vessels in retinal images play an essential part in the diagnoses of an eye sicknesses. We proposed a less computational unsupervised automated technique with promising results for detection of retinal vasculature by using morphological hessian based approach and region based Otsu thresholding. Contrast Limited Adaptive Histogram Equalization (CLAHE) and morphological filters have been used for enhancement and to remove low frequency noise or geometrical objects, respectively. The hessian matrix and eigenvalues approach used has been in a modified form at two different scales to extract wide and thin vessel enhanced images separately. Otsu thresholding has been further applied in a novel way to classify vessel and non-vessel pixels from both enhanced images. Finally, postprocessing steps has been used to eliminate the unwanted region/segment, non-vessel pixels, disease abnormalities and noise, to obtain a final segmented image. The proposed technique has been analyzed on the openly accessible DRIVE (Digital Retinal Images for Vessel Extraction) and STARE (STructured Analysis of the REtina) databases along with the ground truth data that has been precisely marked by the experts. PMID:27441646

A comparison of methods for evaluating structure during ship collisions

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

Ammerman, D.J.; Daidola, J.C.

1996-10-01

A comparison is provided of the results of various methods for evaluating structure during a ship-to-ship collision. The baseline vessel utilized in the analyses is a 67.4 meter in length displacement hull struck by an identical vessel traveling at speeds ranging from 10 to 30 knots. The structural response of the struck vessel and motion of both the struck and striking vessels are assessed by finite element analysis. These same results are then compared to predictions utilizing the {open_quotes}Tanker Structural Analysis for Minor Collisions{close_quotes} (TSAMC) Method, the Minorsky Method, the Haywood Collision Process, and comparison to full-scale tests. Consideration ismore » given to the nature of structural deformation, absorbed energy, penetration, rigid body motion, and virtual mass affecting the hydrodynamic response. Insights are provided with regard to the calibration of the finite element model which was achievable through utilizing the more empirical analyses and the extent to which the finite element analysis is able to simulate the entire collision event. 7 refs., 8 figs., 4 tabs.« less

46 CFR 356.9 - Tiered ownership structures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 8 2010-10-01 2010-10-01 false Tiered ownership structures. 356.9 Section 356.9 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MISCELLANEOUS REQUIREMENTS FOR VESSELS OF 100 FEET OR GREATER IN REGISTERED LENGTH TO OBTAIN A FISHERY ENDORSEMENT TO THE VESSEL'S DOCUMENTATION...

46 CFR 356.9 - Tiered ownership structures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 8 2011-10-01 2011-10-01 false Tiered ownership structures. 356.9 Section 356.9 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MISCELLANEOUS REQUIREMENTS FOR VESSELS OF 100 FEET OR GREATER IN REGISTERED LENGTH TO OBTAIN A FISHERY ENDORSEMENT TO THE VESSEL'S DOCUMENTATION...

Glass Membrane For Controlled Diffusion Of Gases

DOEpatents

Shelby, James E.; Kenyon, Brian E.

2001-05-15

A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.

Structural response of 1/20-scale models of the Clinch River Breeder Reactor to a simulated hypothetical core-disruptive accident

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-s 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, and an upper internals structure (UIS).« less

Design of a dee vacuum vessel for Doublet III

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

Davis, L.G.

1983-04-01

The Doublet III tokamak is to be modified wherein the original 'doublet' plasma containment vacuum vessel will be exchanged with one of a large dee-shaped cross section. The basic dimensions of the dee vessel will allow plasmas of 1.7-m major radius, 0.7-m minor radius, and a vertical elongation of 1.8. Installation of a large dee vessel in Doublet III is made possible by the demountable toroidal field coils and the large, low-ripple volume they include. Ripple at the plasma edge will be less than one percent. The plasma parameters affecting the design of the vessel will be reviewed including plasmamore » current, power, disruption time, allowable error field, impurity control techniques, pulse length, and limiter schemes. A driving requirement for the design of the vessel is to maximize the access to the plasma for auxiliary heating (both neutral beam injection and radio frequency heating), diagnostics, developmental component and material testing, and pumping. The dee vessel is structurally designed along the same lines as the present vessel: an Inconel 625, all-welded, continuous chamber in a corrugated sandwich construction. An overview of the vessel design and its solutions to the design criteria will be presented. An overview will also be presented of the entire modification project which includes replacement of some coils, and addition of support structure, limiters and vessel armor, and power system components.« less

29 CFR 1910.402 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Code or equivalent: ASME (American Society of Mechanical Engineers) Boiler and Pressure Vessel Code... pressure: The pressure at which a pressure containment device would fail structurally. Cylinder: A pressure vessel for the storage of gases. Decompression chamber: A pressure vessel for human occupancy such as a...

29 CFR 1910.402 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Code or equivalent: ASME (American Society of Mechanical Engineers) Boiler and Pressure Vessel Code... pressure: The pressure at which a pressure containment device would fail structurally. Cylinder: A pressure vessel for the storage of gases. Decompression chamber: A pressure vessel for human occupancy such as a...

29 CFR 1910.402 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Code or equivalent: ASME (American Society of Mechanical Engineers) Boiler and Pressure Vessel Code... pressure: The pressure at which a pressure containment device would fail structurally. Cylinder: A pressure vessel for the storage of gases. Decompression chamber: A pressure vessel for human occupancy such as a...

Analysis and Visualization of Nerve Vessel Contacts for Neurovascular Decompression

NASA Astrophysics Data System (ADS)

Süßmuth, Jochen; Piazza, Alexander; Enders, Frank; Naraghi, Ramin; Greiner, Günther; Hastreiter, Peter

Neurovascular compression syndromes are caused by a pathological contact between cranial nerves and vascular structures at the surface of the brainstem. Aiming at improved pre-operative analysis of the target structures, we propose calculating distance fields to provide quantitative information of the important nerve-vessel contacts. Furthermore, we suggest reconstructing polygonal models for the nerves and vessels. Color-coding with the respective distance information is used for enhanced visualization. Overall, our new strategy contributes to a significantly improved clinical understanding.

Pharmacological potential of exercise and RAS vasoactive peptides for prevention of diseases.

PubMed

Petriz, Bernardo de Assis; de Almeida, Jeeser Alves; Migliolo, Ludovico; Franco, Octavio Luiz

2013-09-01

The Renin-Angiotensin-System (RAS) molecular network has been widely studied, especially with attention to angiotensin II, the main effector peptide among RAS. The relation of Ang II to hypertension pathogenesis has led to research being extended to other molecules from the RAS, such as angiotensin III and IV, angiotensin (1-5), and angiotensin (1-9). Moreover, great pharmacologic advances have been made in hypertension treatment by inhibiting renin and angiotensin converting enzymes and blocking the bonding of angiotensin II to its receptor AT1. Thus, RAS molecular signaling and its effect on blood pressure as well as its relationship to renal function and cardiovascular disease are still being investigated. It is a great challenge to fully cover and understand all molecules from the RAS, especially those that interfere with or have vasoactive properties. Some of these targets respond to exercise, stimulating nitric oxide synthesis and endothelial vasodilation. The activation of these specific molecules via exercise is a systematic way of controlling high blood pressure without pharmacological treatment. Angiotensin (1-7) has been focused due to its vasodilation properties and its responses to exercise, improving vascular function. Thus, stimulation of the ACE2/Ang (1-7)/Mas axis has been gaining ground as a prospective clinical means to attenuate cardiovascular diseases such as hypertension by modulating RAS activity. This review focuses on the vasoactive peptides from the RAS, their responses to exercise and possible trends for pharmacological development. In several cases where exercise training is not achievable, cardiovascular drug therapy with vasodilator peptides may possibly be an option.

Effects of soya oligosaccharides and soya oligopeptides on lipid metabolism in hyperlipidaemic rats.

PubMed

Xie, Shali; Zhu, Jundong; Zhang, Yanqi; Shi, Kai; Shi, Yuangang; Ma, Xiao

2012-08-01

In the present study, we aimed to examine the effects of soya oligosaccharides (SOS) and soya oligopeptides (SOP) on blood lipid levels, release of vasoactive substances, antioxidant activity and faecal bile acid (FBA) excretion in rats fed a high-fat diet (HFD). Male Sprague-Dawley rats were evenly divided into five groups according to diets as follows: regular diet (control), HFD, HFD enriched with 2 % of SOS (SOS), HFD enriched with 3 % of SOP (SOP) and HFD enriched with 2 % SOS and 3 % SOP (SOSP). The results showed that SOS and SOP significantly reduced plasma total cholesterol, LDL-cholesterol and TAG, whereas HDL-cholesterol concentration was significantly increased. Furthermore, SOS and SOP reduced plasma apoB, apoE and the apoB:apoAI ratio, whereas apoAI was significantly increased. Moreover, SOS and SOP also reduced plasma thromboxane A₂ (TXA₂) and the TXA₂:prostacyclin (PGI₂) ratio, whereas plasma PGI₂ and nitric oxide were significantly increased. In addition, SOS and SOP significantly reduced serum and liver malondialdehyde concentrations and increased FBA excretion. However, we did not observe obvious influences of SOS and SOP on superoxide dismutase activities in the liver of HFD-fed rats. The combination of 2 % SOS and 3 % SOP showed a more marked effect than SOS or SOP alone in improving the lipid profile, release of vasoactive substances and increasing FBA excretion (P < 0.05). In summary, SOS and SOP might help prevent atherosclerosis through improving abnormal blood lipid levels, regulating vasoactive substances and protecting against oxidative stress.

The effects of delivery route and anesthesia type on early postnatal weight loss in newborns: the role of vasoactive hormones.

PubMed

Okumus, Nurullah; Atalay, Yildiz; Onal, Eray E; Turkyilmaz, Canan; Senel, Saliha; Gunaydin, Berrin; Pasaoglu, Hatice; Koc, Esin; Ergenekon, Ebru; Unal, Suna

2011-01-01

To investigate the effects of delivery route and maternal anesthesia type and the roles of vasoactive hormones on early postnatal weight loss in term newborns. Ninety-four term infants delivered vaginally (group 1, n=31), cesarean section (C/S) with general anesthesia (GA) (group 2, n=29), and C/S with epidural anesthesia (EA) (group 3, n=34) were included in this study. All infants were weighed at birth and on the second day of life and intravenous (IV) fluid infused to the mothers for the last 6 h prior to delivery was recorded. Serum electrolytes, osmolality, N-terminal proANP (NT-proANP), brain natriuretic peptide (BNP), aldosterone and plasma antidiuretic hormone (ADH) concentrations were measured at cord blood and on the second day of life. Our research showed that postnatal weight loss of infants was higher in C/S than vaginal deliveries (5.7% vs. 1.3%) (p < 0.0001) and in EA group than GA group (6.8% vs. 4.3%) (p < 0.0001). Postnatal weight losses were correlated with IV fluid volume infused to the mothers for the last 6 h prior to delivery (R = 0.814, p = 0.000) and with serum NT-proANP (R = 0.418, p = 0.000), BNP (R = 0.454, p = 0.000), and ADH (R = 0.509, p = 0.000) but not with aldosterone concentrations (p > 0.05). Large amounts of IV fluid given to the mothers who were applied EA prior to the delivery affect their offsprings' postnatal weight loss via certain vasoactive hormones.

Reconstruction of vessel structures from serial whole slide sections of murine liver samples

NASA Astrophysics Data System (ADS)

Schwier, Michael; Hahn, Horst K.; Dahmen, Uta; Dirsch, Olaf

2013-03-01

Image-based analysis of the vascular structures of murine liver samples is an important tool for scientists to understand liver physiology and morphology. Typical assessment methods are MicroCT, which allows for acquiring images of the whole organ while lacking resolution for fine details, and confocal laser scanning microscopy, which allows detailed insights into fine structures while lacking the broader context. Imaging of histological serial whole slide sections is a recent technology able to fill this gap, since it provides a fine resolution up to the cellular level, but on a whole organ scale. However, whole slide imaging is a modality providing only 2D images. Therefore the challenge is to use stacks of serial sections from which to reconstruct the 3D vessel structures. In this paper we present a semi-automatic procedure to achieve this goal. We employ an automatic method that detects vessel structures based on continuity and shape characteristics. Furthermore it supports the user to perform manual corrections where required. With our methods we were able to successfully extract and reconstruct vessel structures from a stack of 100 and a stack of 397 serial sections of a mouse liver lobe, thus proving the potential of our approach.

Is It True That Certain Foods Worsen Anxiety and Others Have a Calming Effect?

MedlinePlus

... degree of hypohydration adversely influences cognition: A mediator analysis. American Journal of Clinical Nutrition. 2016;104:603. Skypala IJ, et al. Sensitivity to food additives, vaso-active amines and salicylates: A review ...

50 CFR 648.11 - At-sea sea sampler/observer coverage.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Identification of the management, organizational structure, and ownership structure of the applicant's business... crew. (2) Allow the sea sampler/observer access to and use of the vessel's communications equipment and... navigation equipment and personnel upon request to determine the vessel's position. (4) Notify the sea...

Lung vessel segmentation in CT images using graph-cuts

NASA Astrophysics Data System (ADS)

Zhai, Zhiwei; Staring, Marius; Stoel, Berend C.

2016-03-01

Accurate lung vessel segmentation is an important operation for lung CT analysis. Filters that are based on analyzing the eigenvalues of the Hessian matrix are popular for pulmonary vessel enhancement. However, due to their low response at vessel bifurcations and vessel boundaries, extracting lung vessels by thresholding the vesselness is not sufficiently accurate. Some methods turn to graph-cuts for more accurate segmentation, as it incorporates neighbourhood information. In this work, we propose a new graph-cuts cost function combining appearance and shape, where CT intensity represents appearance and vesselness from a Hessian-based filter represents shape. Due to the amount of voxels in high resolution CT scans, the memory requirement and time consumption for building a graph structure is very high. In order to make the graph representation computationally tractable, those voxels that are considered clearly background are removed from the graph nodes, using a threshold on the vesselness map. The graph structure is then established based on the remaining voxel nodes, source/sink nodes and the neighbourhood relationship of the remaining voxels. Vessels are segmented by minimizing the energy cost function with the graph-cuts optimization framework. We optimized the parameters used in the graph-cuts cost function and evaluated the proposed method with two manually labeled sub-volumes. For independent evaluation, we used 20 CT scans of the VESSEL12 challenge. The evaluation results of the sub-volume data show that the proposed method produced a more accurate vessel segmentation compared to the previous methods, with F1 score 0.76 and 0.69. In the VESSEL12 data-set, our method obtained a competitive performance with an area under the ROC curve of 0.975, especially among the binary submissions.

Electron-immunocytochemical studies of perivascular nerves of mesenteric and renal arteries of golden hamsters during and after arousal from hibernation

PubMed Central

SAITONGDEE, PORNCHARN; MILNER, PAMELA; LOESCH, ANDRZEJ; KNIGHT, GILLIAN; BURNSTOCK, GEOFFREY

1999-01-01

Electron immunocytochemistry was used to examine perivascular nerves of hamster mesenteric and renal arteries during hibernation and 2 h after arousal from hibernation. Vessels from cold-exposed but nonhibernating, and normothermic control hamsters were also examined. During hibernation the percentage of axon profiles in mesenteric and renal arteries that were immunopositive for markers of sympathetic nerves, tyrosine hydroxylase (TH) and neuropeptide Y (NPY), were increased 2–3 fold compared with normothermic and cold control animals. This increase was reduced markedly only 2 h after arousal from hibernation. The small percentage of nitric oxide synthase-1-positive axon profiles found in mesenteric (but not renal) arteries was also increased during hibernation and returned towards control values after arousal. In contrast, the percentage of perivascular axons immunostaining for vasoactive intestinal polypeptide (VIP), a marker for parasympathetic nerves, was reduced in mesenteric arteries during hibernation. There was no labelling of perivascular nerves for substance P in either mesenteric or renal arteries. It is suggested that the increase in percentage of TH- and NPY-immunostained perivascular nerves may account for the increased vasoconstriction associated with high vascular resistance that is known to occur during hibernation. The reduction in the percentage of axons positive for VIP in hibernating animals would contribute to this mechanism since this neuropeptide is a vasodilator. PMID:10473299

2D Fast Vessel Visualization Using a Vessel Wall Mask Guiding Fine Vessel Detection

PubMed Central

Raptis, Sotirios; Koutsouris, Dimitris

2010-01-01

The paper addresses the fine retinal-vessel's detection issue that is faced in diagnostic applications and aims at assisting in better recognizing fine vessel anomalies in 2D. Our innovation relies in separating key visual features vessels exhibit in order to make the diagnosis of eventual retinopathologies easier to detect. This allows focusing on vessel segments which present fine changes detectable at different sampling scales. We advocate that these changes can be addressed as subsequent stages of the same vessel detection procedure. We first carry out an initial estimate of the basic vessel-wall's network, define the main wall-body, and then try to approach the ridges and branches of the vasculature's using fine detection. Fine vessel screening looks into local structural inconsistencies in vessels properties, into noise, or into not expected intensity variations observed inside pre-known vessel-body areas. The vessels are first modelled sufficiently but not precisely by their walls with a tubular model-structure that is the result of an initial segmentation. This provides a chart of likely Vessel Wall Pixels (VWPs) yielding a form of a likelihood vessel map mainly based on gradient filter's intensity and spatial arrangement parameters (e.g., linear consistency). Specific vessel parameters (centerline, width, location, fall-away rate, main orientation) are post-computed by convolving the image with a set of pre-tuned spatial filters called Matched Filters (MFs). These are easily computed as Gaussian-like 2D forms that use a limited range sub-optimal parameters adjusted to the dominant vessel characteristics obtained by Spatial Grey Level Difference statistics limiting the range of search into vessel widths of 16, 32, and 64 pixels. Sparse pixels are effectively eliminated by applying a limited range Hough Transform (HT) or region growing. Major benefits are limiting the range of parameters, reducing the search-space for post-convolution to only masked regions, representing almost 2% of the 2D volume, good speed versus accuracy/time trade-off. Results show the potentials of our approach in terms of time for detection ROC analysis and accuracy of vessel pixel (VP) detection. PMID:20706682

Secondary flow structures in a 180∘ elastic curved vessel with torsion under steady and pulsatile inflow conditions

NASA Astrophysics Data System (ADS)

Najjari, Mohammad Reza; Plesniak, Michael W.

2017-11-01

Secondary flow vortical structures were investigated in an elastic 180° curved pipe with and without torsion under steady and pulsatile flow using particle image velocimetry (PIV). The elastic thin-walled curved pipes were constructed using Sylgard 184, and inserted into a bath of refractive index matched fluid to perform PIV. A vortex identification method was employed to identify various vortical structures in the flow. The secondary flow structures in the planar compliant model with dilatation of 0.61%-3.23% under pulsatile flow rate were compared with the rigid vessel model results, and it was found that local vessel compliance has a negligible effect on secondary flow morphology. The secondary flow structures were found to be more sensitive to out of plane curvature (torsion) than to vessel compliance. Torsion distorts the symmetry of secondary flow and results in more complex vortical structures in both steady and pulsatile flows. In high Re number steady flow with torsion, a single dominant vortical structure can be detected at the middle of the 90° cross section. In pulsatile flow with torsion, the split-Dean and Lyne-type vortices with same rotation direction originating from opposite sides of the cross section tend to merge together. supported by GW Center for Biomimetics and Bioinspired Engineering.

Osteoblasts extracellular matrix induces vessel like structures through glycosylated collagen I

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

Palmieri, D.; Valli, M.; Viglio, S.

2010-03-10

Extracellular matrix (ECM) plays a fundamental role in angiogenesis affecting endothelial cells proliferation, migration and differentiation. Vessels-like network formation in vitro is a reliable test to study the inductive effects of ECM on angiogenesis. Here we utilized matrix deposed by osteoblasts as substrate where the molecular and structural complexity of the endogenous ECM is preserved, to test if it induces vessel-like network formation by endothelial cells in vitro. ECM is more similar to the physiological substrate in vivo than other substrates previously utilized for these studies in vitro. Osteogenic ECM, prepared in vitro from mature osteoblasts at the phase ofmore » maximal deposition and glycosylation of collagen I, induces EAhy926, HUVEC, and HDMEC endothelial cells to form vessels-like structures and promotes the activation of metalloproteinase-2 (MMP-2); the functionality of the p-38/MAPK signaling pathway is required. Osteogenic ECM also induces a transient increase of CXCL12 and a decrease of the receptor CXCR4. The induction of vessel-like networks is dependent from proper glycosylation of collagens and does not occur on osteogenic ECMs if deglycosylated by -galactosidase or on less glycosylated ECMs derived from preosteoblasts and normal fibroblasts, while is sustained on ECM from osteogenesis imperfecta fibroblasts only when their mutation is associated with over-glycosylation of collagen type I. These data support that post-translational glycosylation has a role in the induction in endothelial cells in vitro of molecules conductive to self-organization in vessels-like structures.« less

Simulation of NO and O2 transport facilitated by polymerized hemoglobin solutions in an arteriole that takes into account wall shear stress-induced NO production.

PubMed

Zhou, Yipin; Cabrales, Pedro; Palmer, Andre F

2012-03-01

A mathematical model was developed to study nitric oxide (NO) and oxygen (O(2)) transport in an arteriole and surrounding tissues exposed to a mixture of red blood cells (RBCs) and hemoglobin (Hb)-based O(2) carriers (HBOCs). A unique feature of this model is the inclusion of blood vessel wall shear stress-induced production of endothelial-derived NO, which is very sensitive to the viscosity of the RBC and HBOC mixture traversing the blood vessel lumen. Therefore in this study, a series of polymerized bovine Hb (PolyHb) solutions with high viscosity, varying O(2) affinities, NO dioxygenation rate constants and O(2) dissociation rate constants that were previously synthesized and characterized by our group was evaluated via mathematical modeling, in order to investigate the effect of these biophysical properties on the transport of NO and O(2) in an arteriole and its surrounding tissues subjected to anemia with the commercial HBOC Oxyglobin® and cell-free bovine Hb (bHb) serving as appropriate controls. The computer simulation results indicated that transfusion of high viscosity PolyHb solutions promoted blood vessel wall shear stress dependent generation of the vasodilator NO, especially in the blood vessel wall and should transport enough NO inside the smooth muscle layer to activate vasodilation compared to the commercial HBOC Oxyglobin® and cell-free bHb. However, NO scavenging in the arteriole lumen was unavoidable due to the intrinsic high NO dioxygenation rate constant of the HBOCs being studied. This study also observed that all PolyHbs could potentially improve tissue oxygenation under hypoxic conditions, while low O(2) affinity PolyHbs were more effective in oxygenating tissues under normoxic conditions compared with high O(2) affinity PolyHbs. In addition, all ultrahigh molecular weight PolyHbs displayed higher O(2) transfer rates than the commercial HBOC Oxyglobin® and cell-free bHb. Therefore, these results suggest that ultrahigh molecular weight PolyHb solutions could be used as safe and efficacious O(2) carriers for use in transfusion medicine. It also suggests that future generations of PolyHb solutions should possess lower NO dioxygenation reaction rate constants in order to reduce NO scavenging, while maintaining high solution viscosity to take advantage of wall shear stress-induced NO production. Taken together, we suggest that this mathematical model can be used to predict the vasoactivity of HBOCs and help guide the design and optimization of the next generation of HBOCs for use in transfusion medicine. Copyright © 2011 Elsevier B.V. All rights reserved.

Carbon Monoxide and Nitric Oxide Mediate Cytoskeletal Reorganization in Microvascular Cells via Vasodilator-Stimulated Phosphoprotein Phosphorylation

PubMed Central

Li Calzi, Sergio; Purich, Daniel L.; Chang, Kyung Hee; Afzal, Aqeela; Nakagawa, Takahiko; Busik, Julia V.; Agarwal, Anupam; Segal, Mark S.; Grant, Maria B.

2008-01-01

OBJECTIVE— We examined the effect of the vasoactive agents carbon monoxide (CO) and nitric oxide (NO) on the phosphorylation and intracellular redistribution of vasodilator-stimulated phosphoprotein (VASP), a critical actin motor protein required for cell migration that also controls vasodilation and platelet aggregation. RESEARCH DESIGN AND METHODS— We examined the effect of donor-released CO and NO in endothelial progenitor cells (EPCs) and platelets from nondiabetic and diabetic subjects and in human microvascular endothelial cells (HMECs) cultured under low (5.5 mmol/l) or high (25 mmol/l) glucose conditions. VASP phosphorylation was evaluated using phosphorylation site-specific antibodies. RESULTS— In control platelets, CO selectively promotes phosphorylation at VASP Ser-157, whereas NO promotes phosphorylation primarily at Ser-157 and also at Ser-239, with maximal responses at 1 min with both agents on Ser-157 and at 15 min on Ser-239 with NO treatment. In diabetic platelets, neither agent resulted in VASP phosphorylation. In nondiabetic EPCs, NO and CO increased phosphorylation at Ser-239 and Ser-157, respectively, but this response was markedly reduced in diabetic EPCs. In endothelial cells cultured under low glucose conditions, both CO and NO induced phosphorylation at Ser-157 and Ser-239; however, this response was completely lost when cells were cultured under high glucose conditions. In control EPCs and in HMECs exposed to low glucose, VASP was redistributed to filopodia-like structures following CO or NO exposure; however, redistribution was dramatically attenuated under high glucose conditions. CONCLUSIONS— Vasoactive gases CO and NO promote cytoskeletal changes through site- and cell type–specific VASP phosphorylation, and in diabetes, blunted responses to these agents may lead to reduced vascular repair and tissue perfusion. PMID:18559661

Increased endothelial apoptotic cell density in human diabetic erectile tissue--comparison with clinical data.

PubMed

Costa, Carla; Soares, Raquel; Castela, Angela; Adães, Sara; Hastert, Véronique; Vendeira, Pedro; Virag, Ronald

2009-03-01

Erectile dysfunction (ED) is a common complication of diabetes. Endothelial cell (EC) dysfunction is one of the main mechanisms of diabetic ED. However, loss of EC integrity has never been assessed in human diabetic corpus cavernosum. To identify and quantify apoptotic cells in human diabetic and normal erectile tissue and to compare these results with each patient's clinical data and erection status. Eighteen cavernosal samples were collected, 13 from diabetics with ED and 5 from nondiabetic individuals. Cavernosal structure and cell proliferation status were evaluated by immunohistochemistry. Tissue integrity was assessed by terminal transferase dUTP nick end labeling assay, an index of apoptotic cell density (ACD) established and compared with each patient age, type of diabetes, arterial risk factors number, arterial/veno-occlusive disease, response to intracavernous vasoactive injections (ICI), and penile nitric oxide release test (PNORT). Establish an index of ACD and correlate those results with patient clinical data. Nondiabetic samples presented few scattered cells in apoptosis and an ACD of 7.15 +/- 0.44 (mean apoptotic cells/tissue area mm(2) +/- standard error). The diabetic group showed an increased ACD of 23.82 +/- 1.53, and apoptotic cells were located specifically at vascular sites. Rehabilitation of these endothelial lesions seemed impaired, as no evidence of EC proliferation was observed. Furthermore, higher ACD in diabetic individuals correlated to poor response to PNORT and to ICI. We provided evidence for the first time that loss of cavernosal EC integrity is a crucial event involved in diabetic ED. Furthermore, we were able to establish a threshold between ACD values and cavernosal tissue functionality, as assessed by PNORT and vasoactive ICI.

Making Large Composite Vessels Without Autoclaves

NASA Technical Reports Server (NTRS)

Sigur, W. A.

1989-01-01

Method for making fiber-reinforced composite structure relies on heating and differential thermal expansion to provide temperature and pressure necessary to develop full strength, without having to place structure in large, expensive autoclave. Layers of differentially expanding material squeeze fiber-reinforce composite between them when heated. Method suitable for such cylindrical structures as pressure vessels and tanks. Used for both resin-matrix and metal-matrix composites.

VASCULAR AND THROMBOGENIC EFFECTS OF PULMONARY EXPOSURE TO LIBBY AMPHIBOLE

EPA Science Inventory

Acute pulmonary injury and chronic disease can impact the systemic vasculature through the release of inflammogenic and vasoactive mediators from the lung into the circulation. Exposure to Libby amphibole (LA) asbestos is associated with increased human cardiovascular mortality a...

Renal blood flow and oxygenation drive nephron progenitor differentiation.

PubMed

Rymer, Christopher; Paredes, Jose; Halt, Kimmo; Schaefer, Caitlin; Wiersch, John; Zhang, Guangfeng; Potoka, Douglas; Vainio, Seppo; Gittes, George K; Bates, Carlton M; Sims-Lucas, Sunder

2014-08-01

During kidney development, the vasculature develops via both angiogenesis (branching from major vessels) and vasculogenesis (de novo vessel formation). The formation and perfusion of renal blood vessels are vastly understudied. In the present study, we investigated the regulatory role of renal blood flow and O2 concentration on nephron progenitor differentiation during ontogeny. To elucidate the presence of blood flow, ultrasound-guided intracardiac microinjection was performed, and FITC-tagged tomato lectin was perfused through the embryo. Kidneys were costained for the vasculature, ureteric epithelium, nephron progenitors, and nephron structures. We also analyzed nephron differentiation in normoxia compared with hypoxia. At embryonic day 13.5 (E13.5), the major vascular branches were perfused; however, smaller-caliber peripheral vessels remained unperfused. By E15.5, peripheral vessels started to be perfused as well as glomeruli. While the interior kidney vessels were perfused, the peripheral vessels (nephrogenic zone) remained unperfused. Directly adjacent and internal to the nephrogenic zone, we found differentiated nephron structures surrounded and infiltrated by perfused vessels. Furthermore, we determined that at low O2 concentration, little nephron progenitor differentiation was observed; at higher O2 concentrations, more differentiation of the nephron progenitors was induced. The formation of the developing renal vessels occurs before the onset of blood flow. Furthermore, renal blood flow and oxygenation are critical for nephron progenitor differentiation. Copyright © 2014 the American Physiological Society.

Distributed sensing of Composite Over-wrapped Pressure Vessel using Fiber-Bragg Gratings at Ambient and Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Grant, Joseph

2005-01-01

Fiber Bragg gratings are use to monitor the structural properties of composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in laminate structure. The fiber Bragg sensors are both embedded within the composite laminates and bonded to the surface of the vessel with varying orientations with respect to the carbon fiber in the epoxy matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 2800 psi. This is done at both ambient and cryogenic temperatures using water and liquid nitrogen. The recorded response is compared with the response from conventional strain gauge also present on the vessel. Additionally, several vessels were tested that had been damaged to simulate different type of events, such as cut tow, delimitation and impact damage.

Distributed Sensing of Composite Over-wrapped Pressure Vessel Using Fiber-Bragg Gratings at Ambient and Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Grant, Joseph

2004-01-01

Fiber Bragg gratings are use to monitor the structural properties of composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in laminate structure. The fiber Bragg sensors are both embedded within the composite laminates and bonded to the surface of the vessel with varying orientations with respect to the carbon fiber in the epoxy matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 2800 psi. This is done at both ambient and cryogenic temperatures using water and liquid nitrogen. The recorded response is compared with the response from conventional strain gauge also present on the vessel. Additionally, several vessels were tested that had been damaged to simulate different type of events, such as cut tow, delimitation and impact damage.

Cadaver study of anatomic landmark identification for placing ankle arthroscopy portals.

PubMed

Scheibling, B; Koch, G; Clavert, P

2017-05-01

Arthroscopy-assisted surgery is now widely used at the ankle for osteochondral lesions of the talus, anterior and posterior impingement syndromes, talocrural or subtalar fusion, foreign body removal, and ankle instability. Injuries to the vessels and nerves may occur during these procedures. To determine whether ultrasound topographic identification of vulnerable structures decreased the risk of iatrogenic injuries to vessels, nerves, and tendons and influenced the distance separating vulnerable structures from the arthroscope introduced through four different portals. Ultrasonography to identify vulnerable structures before or during arthroscopic surgery on the ankle may be useful. Twenty fresh cadaver ankles from body donations to the anatomy institute in Strasbourg, France, were divided into two equal groups. Preoperative ultrasonography to mark the trajectories of vessels, nerves, and tendons was performed in one group but not in the other. The portals were created using a 4-mm trocar. Each portal was then dissected. The primary evaluation criterion was the presence or absence of injuries to vessels, nerves, and tendons. The secondary evaluation criterion was the distance between these structures and the arthroscope. No tendon injuries occurred with ultrasonography. Without ultrasonography, there were two full-thickness tendon lesions, one to the extensor hallucis longus and the other to the Achilles tendon. Furthermore, with the anterolateral, anteromedial, and posteromedial portals, the distance separating the vessels and nerves from the arthroscope was greater with than without ultrasonography (P=0.041, P=0.005, and P=0.002), respectively; no significant difference was found with the anterior portal. Preoperative ultrasound topographic identification decreases the risk of iatrogenic injury to the vessels, nerves, and tendons during ankle arthroscopy and places these structures at a safer distance from the arthroscope. Our hypothesis was confirmed. IV, cadaver study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Dipeptidyl peptidase IV activity and/or structure homologs: Contributing factors in the pathogenesis of rheumatoid arthritis?

PubMed Central

Sedo, Aleksi; Duke-Cohan, Jonathan S; Balaziova, Eva; Sedova, Liliana R

2005-01-01

Several of the proinflammatory peptides involved in rheumatoid arthritis pathogenesis, including peptides induced downstream of tumor necrosis factor-α as well as the monocyte/T cell-attracting chemokines RANTES and stromal cell-derived factor (SDF)-1α and the neuropeptides vasoactive intestinal peptide (VIP) and substance P, have their biological half-lives controlled by dipeptidyl peptidase IV (DPPIV). Proteolysis by DPPIV regulates not only the half-life but also receptor preference and downstream signaling. In this article, we examine the role of DPPIV homologs, including CD26, the canonical DPPIV, and their substrates in the pathogenesis of rheumatoid arthritis. The differing specific activities of the DPPIV family members and their differential inhibitor response provide new insights into therapeutic design. PMID:16277701

Skeletonization applied to magnetic resonance angiography images

NASA Astrophysics Data System (ADS)

Nystroem, Ingela

1998-06-01

When interpreting and analyzing magnetic resonance angiography images, the 3D overall tree structure and the thickness of the blood vessels are of interest. This shape information may be easier to obtain from the skeleton of the blood vessels. Skeletonization of digital volume objects denotes either reduction to a 2D structure consisting of 3D surfaces, and curves, or reduction to a 1D structure consisting of 3D curves only. Thin elongated objects, such as blood vessels, are well suited for reduction to curve skeletons. Our results indicate that the tree structure of the vascular system is well represented by the skeleton. Positions for possible artery stenoses may be identified by locating local minima in curve skeletons, where the skeletal voxels are labeled with the distance to the original background.

Fpga based hardware synthesis for automatic segmentation of retinal blood vessels in diabetic retinopathy images.

PubMed

Sivakamasundari, J; Kavitha, G; Sujatha, C M; Ramakrishnan, S

2014-01-01

Diabetic Retinopathy (DR) is a disorder that affects the structure of retinal blood vessels due to long-standing diabetes mellitus. Real-Time mass screening system for DR is vital for timely diagnosis and periodic screening to prevent the patient from severe visual loss. Human retinal fundus images are widely used for an automated segmentation of blood vessel and diagnosis of various blood vessel disorders. In this work, an attempt has been made to perform hardware synthesis of Kirsch template based edge detection for segmentation of blood vessels. This method is implemented using LabVIEW software and is synthesized in field programmable gate array board to yield results in real-time application. The segmentation of blood vessels using Kirsch based edge detection is compared with other edge detection methods such as Sobel, Prewitt and Canny. The texture features such as energy, entropy, contrast, mean, homogeneity and structural feature namely ratio of vessel to vessel free area are obtained from the segmented images. The performance of segmentation is analysed in terms of sensitivity, specificity and accuracy. It is observed from the results that the Kirsch based edge detection technique segmented the edges of blood vessels better than other edge detection techniques. The ratio of vessel to vessel free area classified the normal and DR affected retinal images more significantly than other texture based features. FPGA based hardware synthesis of Kirsch edge detection method is able to differentiate normal and diseased images with high specificity (93%). This automated segmentation of retinal blood vessels system could be used in computer-assisted diagnosis for diabetic retinopathy screening in real-time application.

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

Modulation of Endothelial Glycocalyx Structure under Inflammatory Conditions

PubMed Central

Kolářová, Hana; Ambrůzová, Barbora; Švihálková Šindlerová, Lenka; Klinke, Anna; Kubala, Lukáš

2014-01-01

The glycocalyx of the endothelium is an intravascular compartment that creates a barrier between circulating blood and the vessel wall. The glycocalyx is suggested to play an important role in numerous physiological processes including the regulation of vascular permeability, the prevention of the margination of blood cells to the vessel wall, and the transmission of shear stress. Various theoretical models and experimental approaches provide data about changes to the structure and functions of the glycocalyx under various types of inflammatory conditions. These alterations are suggested to promote inflammatory processes in vessels and contribute to the pathogenesis of number of diseases. In this review we summarize current knowledge about the modulation of the glycocalyx under inflammatory conditions and the consequences for the course of inflammation in vessels. The structure and functions of endothelial glycocalyx are briefly discussed in the context of methodological approaches regarding the determination of endothelial glycocalyx and the uncertainty and challenges involved in glycocalyx structure determination. In addition, the modulation of glycocalyx structure under inflammatory conditions and the possible consequences for pathogenesis of selected diseases and medical conditions (in particular, diabetes, atherosclerosis, ischemia/reperfusion, and sepsis) are summarized. Finally, therapeutic strategies to ameliorate glycocalyx dysfunction suggested by various authors are discussed. PMID:24803742

MicroCT angiography detects vascular formation and regression in skin wound healing

PubMed Central

Urao, Norifumi; Okonkwo, Uzoagu A.; Fang, Milie M.; Zhuang, Zhen W.; Koh, Timothy J.; DiPietro, Luisa A.

2016-01-01

Properly regulated angiogenesis and arteriogenesis are essential for effective wound healing. Tissue injury induces robust new vessel formation and subsequent vessel maturation, which involves vessel regression and remodeling. Although formation of functional vasculature is essential for healing, alterations in vascular structure over the time course of skin wound healing are not well understood. Here, using high-resolution ex vivo X-ray micro-computed tomography (microCT), we describe the vascular network during healing of skin excisional wounds with highly detailed three-dimensional (3D) reconstructed images and associated quantitative analysis. We found that relative vessel volume, surface area and branching number are significantly decreased in wounds from day 7 to day 14 and 21. Segmentation and skeletonization analysis of selected branches from high-resolution images as small as 2.5 μm voxel size show that branching orders are decreased in the wound vessels during healing. In histological analysis, we found that the contrast agent fills mainly arterioles, but not small capillaries nor large veins. In summary, high-resolution microCT revealed dynamic alterations of vessel structures during wound healing. This technique may be useful as a key tool in the study of the formation and regression of wound vessels. PMID:27009591

46 CFR 115.600 - Drydock examination, internal structural examination, and underwater survey intervals.

Code of Federal Regulations, 2010 CFR

2010-10-01

... a United States port, it must undergo the required examination before sailing. (c) If your vessel is... hull exams and two internal structural exams within any five-year period. If a vessel completes a satisfactory alternate hull exam, with the underwater survey portion conducted predominantly by an approved...

46 CFR 177.340 - Alternate design considerations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Alternate design considerations. 177.340 Section 177.340 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.340 Alternate design considerations. When the structure of vessel is of novel design,...

46 CFR 177.340 - Alternate design considerations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Alternate design considerations. 177.340 Section 177.340 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.340 Alternate design considerations. When the structure of vessel is of novel design,...

46 CFR 177.340 - Alternate design considerations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Alternate design considerations. 177.340 Section 177.340 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Hull Structure § 177.340 Alternate design considerations. When the structure of vessel is of novel design,...

Structural integrity of a confinement vessel for testing nuclear fuels for space propulsion

NASA Astrophysics Data System (ADS)

Bergmann, V. L.

Nuclear propulsion systems for rockets could significantly reduce the travel time to distant destinations in space. However, long before such a concept can become reality, a significant effort must be invested in analysis and ground testing to guide the development of nuclear fuels. Any testing in support of development of nuclear fuels for space propulsion must be safely contained to prevent the release of radioactive materials. This paper describes analyses performed to assess the structural integrity of a test confinement vessel. The confinement structure, a stainless steel pressure vessel with bolted flanges, was designed for operating static pressures in accordance with the ASME Boiler and Pressure Vessel Code. In addition to the static operating pressures, the confinement barrier must withstand static overpressures from off-normal conditions without releasing radioactive material. Results from axisymmetric finite element analyses are used to evaluate the response of the confinement structure under design and accident conditions. For the static design conditions, the stresses computed from the ASME code are compared with the stresses computed by the finite element method.

Systemic and Vascular Alterations in Healthy and Cardiovascular Compromised Rats Exposed to Libby Amphibole

EPA Science Inventory

Rationale: Acute pulmonary injury and chronic disease can impact systemic vasculature because the lung capillary network can release inflammogenic and vasoactive mediators into the circulation. Occupational exposure to Libby amphibole (LA) type asbestos is associated with increas...

VANADYL SULFATE INHIBITS NO PRODUCTION VIA THREONINE PHOSPHORYLATION OF ENOS

EPA Science Inventory

Exposure to excessive vanadium (V) occurs in some occupations and with consumption of some dietary regimens for weight reduction and body-building. Because vanadium is vasoactive, individuals exposed to excessive V may develop adverse vascular effects. We showed previously that v...

Brain vascular image segmentation based on fuzzy local information C-means clustering

NASA Astrophysics Data System (ADS)

Hu, Chaoen; Liu, Xia; Liang, Xiao; Hui, Hui; Yang, Xin; Tian, Jie

2017-02-01

Light sheet fluorescence microscopy (LSFM) is a powerful optical resolution fluorescence microscopy technique which enables to observe the mouse brain vascular network in cellular resolution. However, micro-vessel structures are intensity inhomogeneity in LSFM images, which make an inconvenience for extracting line structures. In this work, we developed a vascular image segmentation method by enhancing vessel details which should be useful for estimating statistics like micro-vessel density. Since the eigenvalues of hessian matrix and its sign describes different geometric structure in images, which enable to construct vascular similarity function and enhance line signals, the main idea of our method is to cluster the pixel values of the enhanced image. Our method contained three steps: 1) calculate the multiscale gradients and the differences between eigenvalues of Hessian matrix. 2) In order to generate the enhanced microvessels structures, a feed forward neural network was trained by 2.26 million pixels for dealing with the correlations between multi-scale gradients and the differences between eigenvalues. 3) The fuzzy local information c-means clustering (FLICM) was used to cluster the pixel values in enhance line signals. To verify the feasibility and effectiveness of this method, mouse brain vascular images have been acquired by a commercial light-sheet microscope in our lab. The experiment of the segmentation method showed that dice similarity coefficient can reach up to 85%. The results illustrated that our approach extracting line structures of blood vessels dramatically improves the vascular image and enable to accurately extract blood vessels in LSFM images.

Automatic detection and segmentation of vascular structures in dermoscopy images using a novel vesselness measure based on pixel redness and tubularness

NASA Astrophysics Data System (ADS)

Kharazmi, Pegah; Lui, Harvey; Stoecker, William V.; Lee, Tim

2015-03-01

Vascular structures are one of the most important features in the diagnosis and assessment of skin disorders. The presence and clinical appearance of vascular structures in skin lesions is a discriminating factor among different skin diseases. In this paper, we address the problem of segmentation of vascular patterns in dermoscopy images. Our proposed method is composed of three parts. First, based on biological properties of human skin, we decompose the skin to melanin and hemoglobin component using independent component analysis of skin color images. The relative quantities and pure color densities of each component were then estimated. Subsequently, we obtain three reference vectors of the mean RGB values for normal skin, pigmented skin and blood vessels from the hemoglobin component by averaging over 100000 pixels of each group outlined by an expert. Based on the Euclidean distance thresholding, we generate a mask image that extracts the red regions of the skin. Finally, Frangi measure was applied to the extracted red areas to segment the tubular structures. Finally, Otsu's thresholding was applied to segment the vascular structures and get a binary vessel mask image. The algorithm was implemented on a set of 50 dermoscopy images. In order to evaluate the performance of our method, we have artificially extended some of the existing vessels in our dermoscopy data set and evaluated the performance of the algorithm to segment the newly added vessel pixels. A sensitivity of 95% and specificity of 87% were achieved.

Traversing and labeling interconnected vascular tree structures from 3D medical images

NASA Astrophysics Data System (ADS)

O'Dell, Walter G.; Govindarajan, Sindhuja Tirumalai; Salgia, Ankit; Hegde, Satyanarayan; Prabhakaran, Sreekala; Finol, Ender A.; White, R. James

2014-03-01

Purpose: Detailed characterization of pulmonary vascular anatomy has important applications for the diagnosis and management of a variety of vascular diseases. Prior efforts have emphasized using vessel segmentation to gather information on the number or branches, number of bifurcations, and branch length and volume, but accurate traversal of the vessel tree to identify and repair erroneous interconnections between adjacent branches and neighboring tree structures has not been carefully considered. In this study, we endeavor to develop and implement a successful approach to distinguishing and characterizing individual vascular trees from among a complex intermingling of trees. Methods: We developed strategies and parameters in which the algorithm identifies and repairs false branch inter-tree and intra-tree connections to traverse complicated vessel trees. A series of two-dimensional (2D) virtual datasets with a variety of interconnections were constructed for development, testing, and validation. To demonstrate the approach, a series of real 3D computed tomography (CT) lung datasets were obtained, including that of an anthropomorphic chest phantom; an adult human chest CT; a pediatric patient chest CT; and a micro-CT of an excised rat lung preparation. Results: Our method was correct in all 2D virtual test datasets. For each real 3D CT dataset, the resulting simulated vessel tree structures faithfully depicted the vessel tree structures that were originally extracted from the corresponding lung CT scans. Conclusion: We have developed a comprehensive strategy for traversing and labeling interconnected vascular trees and successfully implemented its application to pulmonary vessels observed using 3D CT images of the chest.

Recent Advances in the Gastric Mucosal Protection Against Stress-induced Gastric Lesions. Importance of Renin-angiotensin Vasoactive Metabolites, Gaseous Mediators and Appetite Peptides.

PubMed

Brzozowski, Tomasz; Magierowska, Katarzyna; Magierowski, Marcin; Ptak-Belowska, Agata; Pajdo, Robert; Kwiecien, Slawomir; Olszanecki, Rafal; Korbut, Ryszard

2017-01-01

Stress is known to cause severe adverse effects in the human gastrointestinal tract including mucosal microbleedings and erosions or even gastric ulceration but the mechanism of these complications has not been fully elucidated. The pathogenesis of stress-induced gastric damage involves the fall in Gastric Blood Flow (GBF), an increase in gastric acid secretion and gastric motility, enhanced adrenergic and cholinergic nerve activity and the rise in gastric mucosal generation of reactive oxygen species. The gastric mucosal defense mechanisms against the deleterious effect of stress include the activation of the hypothalamic-pituitary-adrenal axis which has been linked with glucocorticoids release capable of counteracting of stress-induced gastric lesions. Here we summarize the novel gastroprotective mechanisms against stress damage exhibited by angiotensin-(1-7), the newly discovered metabolite of Renin-Angiotensin System (RAS), the gaseous mediators such as nitric oxide (NO), hydrogen sulfide (H2S) or Carbon Monoxide (CO), and the food intake controlling peptides ghrelin, nesfatin- 1 and apelin possibly acting via brain-gut axis. These bioactive molecules such as RAS vasoactive metabolite angiotensin-(1-7) and appetite peptides have been shown to afford gastroprotective effect against stressinduced gastric lesions mainly mediated by an increase in gastric microcirculation. Gaseous mediators protect the gastric mucosa against stress lesions by mechanism involving the activation of PG/COX and CO/HO-1 biosynthetic pathways, and their anti-inflammatory and anti-oxidizing properties. Thus, these new components add new mechanistic aspects to the common cooperation of NO/NO-synthase, PG/COX systems and vasoactive sensory neuropeptides including CGRP but their gastroprotective efficacy against experimental stress ulcerogenesis requires the confirmation in human clinical trials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Radiolabeling and in vitro and in vivo characterization of [18F]FB-[R(8,15,21), L17]-VIP as a PET imaging agent for tumor overexpressed VIP receptors.

PubMed

Cheng, Dengfeng; Yin, Duanzhi; Li, Gucai; Wang, Mingwei; Li, Shiqiang; Zheng, Mingqiang; Cai, Hancheng; Wang, Yongxian

2006-12-01

In an effort to develop a peptide-based radiopharmaceutical for the detection of tumors overexpressed vasoactive intestinal peptide receptors with positron emission tomography, we have prepared a novel [R(8,15,21), L17]-VIP peptide for 18F-labeling. This peptide inhibited 125I-VIP binding to rats lung membranes with high affinity [half-maximal inhibitory concentrations (IC50) of 0.12 nm]. Additionally, [R(8,15,21), L17]-VIP showed higher stability than native vasoactive intestinal peptide in vivo of mice. With N-succinimidyl 4-[18F] fluorobenzoate as labeling prosthetic group, [18F]FB-[R(8,15,21), L17]-VIP was obtained in >99% radiochemical purity within 100 min in decay-for-corrected radiochemical yield of 33.6 +/- 3% (n = 5) and a specific radioactivity 255 GBq/micromol at the end of synthesis. Stability of [18F]FB-[R(8,15,21), L17]-VIP in vitro and in vivo were investigated. Biodistribution of this trace was carried out in mice with induced C26 colorectal tumor. Fast clearance of [18F]FB-[R(8,15,21), L17]-VIP from non-target tissues and specific uptakes by tumors realized higher tumor-to-muscle ratio (3.55) and tumor-to-blood ratio (2.37) 60 min postinjection. Clear difference was observed between the blocking and unblocking experiments in biodistribution and whole body radioautography. [18F]FB-[R(8,15,21), L17]-VIP has demonstrated its potential for diagnosing tumors overexpressed vasoactive intestinal peptide receptors both in vitro and in vivo.

Global Epidemiology of Pediatric Severe Sepsis: The Sepsis Prevalence, Outcomes, and Therapies Study

PubMed Central

Weiss, Scott L.; Pappachan, John; Wheeler, Derek; Jaramillo-Bustamante, Juan C.; Salloo, Asma; Singhi, Sunit C.; Erickson, Simon; Roy, Jason A.; Bush, Jenny L.; Nadkarni, Vinay M.; Thomas, Neal J.

2015-01-01

Rationale: Limited data exist about the international burden of severe sepsis in critically ill children. Objectives: To characterize the global prevalence, therapies, and outcomes of severe sepsis in pediatric intensive care units to better inform interventional trials. Methods: A point prevalence study was conducted on 5 days throughout 2013–2014 at 128 sites in 26 countries. Patients younger than 18 years of age with severe sepsis as defined by consensus criteria were included. Outcomes were severe sepsis point prevalence, therapies used, new or progressive multiorgan dysfunction, ventilator- and vasoactive-free days at Day 28, functional status, and mortality. Measurements and Main Results: Of 6,925 patients screened, 569 had severe sepsis (prevalence, 8.2%; 95% confidence interval, 7.6–8.9%). The patients’ median age was 3.0 (interquartile range [IQR], 0.7–11.0) years. The most frequent sites of infection were respiratory (40%) and bloodstream (19%). Common therapies included mechanical ventilation (74% of patients), vasoactive infusions (55%), and corticosteroids (45%). Hospital mortality was 25% and did not differ by age or between developed and resource-limited countries. Median ventilator-free days were 16 (IQR, 0–25), and vasoactive-free days were 23 (IQR, 12–28). Sixty-seven percent of patients had multiorgan dysfunction at sepsis recognition, with 30% subsequently developing new or progressive multiorgan dysfunction. Among survivors, 17% developed at least moderate disability. Sample sizes needed to detect a 5–10% absolute risk reduction in outcomes within interventional trials are estimated between 165 and 1,437 patients per group. Conclusions: Pediatric severe sepsis remains a burdensome public health problem, with prevalence, morbidity, and mortality rates similar to those reported in critically ill adult populations. International clinical trials targeting children with severe sepsis are warranted. PMID:25734408

Benefits of smart pumps for automated changeovers of vasoactive drug infusion pumps: a quasi-experimental study.

PubMed

Cour, M; Hernu, R; Bénet, T; Robert, J M; Regad, D; Chabert, B; Malatray, A; Conrozier, S; Serra, P; Lassaigne, M; Vanhems, P; Argaud, L

2013-11-01

Manual changeover of vasoactive drug infusion pumps (CVIP) frequently lead to haemodynamic instability. Some of the newest smart pumps allow automated CVIP. The aim of this study was to compare automated CVIP with manual 'Quick Change' relays. We performed a prospective, quasi-experimental study, in a university-affiliated intensive care unit (ICU). All adult patients receiving continuous i.v. infusion of vasoactive drugs were included. CVIP were successively performed manually (Phase 1) and automatically (Phase 2) during two 6-month periods. The primary endpoint was the frequency of haemodynamic incidents related to the relays, which were defined as variations of mean arterial pressure >15 mm Hg or heart rate >15 bpm. The secondary endpoints were the nursing time dedicated to relays and the number of interruptions in care because of CVIP. A multivariate mixed effects logistic regression was fitted for analytic analysis. We studied 1329 relays (Phase 1: 681, Phase 2: 648) from 133 patients (Phase 1: 63, Phase 2: 70). Incidents related to CVIP decreased from 137 (20%) in Phase 1 to 73 (11%) in Phase 2 (P<0.001). Automated relays were independently associated with a 49% risk reduction of CVIP-induced incidents (adjusted OR=0.51, 95% confidence interval 0.34-0.77, P=0.001). Time dedicated to the relays and the number of interruptions in care to manage CVIP were also significantly reduced with automated relays vs manual relays (P=0.001). These results demonstrate the benefits of automated CVIP using smart pumps in limiting the frequency of haemodynamic incidents related to relays and in reducing the nursing workload.

ACE2 and vasoactive peptides: novel players in cardiovascular/renal remodeling and hypertension.

PubMed

Mendoza-Torres, Evelyn; Oyarzún, Alejandra; Mondaca-Ruff, David; Azocar, Andrés; Castro, Pablo F; Jalil, Jorge E; Chiong, Mario; Lavandero, Sergio; Ocaranza, María Paz

2015-08-01

The renin-angiotensin system (RAS) is a key component of cardiovascular physiology and homeostasis due to its influence on the regulation of electrolyte balance, blood pressure, vascular tone and cardiovascular remodeling. Deregulation of this system contributes significantly to the pathophysiology of cardiovascular and renal diseases. Numerous studies have generated new perspectives about a noncanonical and protective RAS pathway that counteracts the proliferative and hypertensive effects of the classical angiotensin-converting enzyme (ACE)/angiotensin (Ang) II/angiotensin type 1 receptor (AT1R) axis. The key components of this pathway are ACE2 and its products, Ang-(1-7) and Ang-(1-9). These two vasoactive peptides act through the Mas receptor (MasR) and AT2R, respectively. The ACE2/Ang-(1-7)/MasR and ACE2/Ang-(1-9)/AT2R axes have opposite effects to those of the ACE/Ang II/AT1R axis, such as decreased proliferation and cardiovascular remodeling, increased production of nitric oxide and vasodilation. A novel peptide from the noncanonical pathway, alamandine, was recently identified in rats, mice and humans. This heptapeptide is generated by catalytic action of ACE2 on Ang A or through a decarboxylation reaction on Ang-(1-7). Alamandine produces the same effects as Ang-(1-7), such as vasodilation and prevention of fibrosis, by interacting with Mas-related GPCR, member D (MrgD). In this article, we review the key roles of ACE2 and the vasoactive peptides Ang-(1-7), Ang-(1-9) and alamandine as counter-regulators of the ACE-Ang II axis as well as the biological properties that allow them to regulate blood pressure and cardiovascular and renal remodeling. © The Author(s), 2015.

Treatment with low-dose atorvastatin, losartan, and their combination increases expression of vasoactive-related genes in rat aortas.

PubMed

Lunder, Mojca; Drevenšek, Gorazd; Černe, Darko; Marc, Janja; Janić, Miodrag; Šabovič, Mišo

2013-03-01

Recently it has been shown that statins and angiotensin receptor blockers (ARBs) at low doses express beneficial pleiotropic vascular effects. We aimed to explore whether these drugs at low doses induce the expression of vasoactive-related genes. Sixty adult Wistar rats were treated with low-dose atorvastatin (2 mg/kg), low-dose losartan (5 mg/kg), their combination or saline daily for 4, 6, or 8 weeks. Expression of the vasoactive-related genes endothelin receptor type A (EDNRA), endothelial nitric oxide synthase 3 (NOS3), inducible nitric oxide synthase 2 (NOS2), and angiotensin II receptor type 1 (AGTRL1a) was measured in isolated thoracic aortas. Expression of EDNRA gradually decreased, the lowest values being obtained after 8 weeks (low-dose atorvastatin, losartan [1.6- and 1-7-fold vs controls, respectively; both P < .05], and the combination [2.3-fold vs control, P < .001]). The highest values of NOS3 were obtained after 6 weeks (low-dose atorvastatin, losartan, and their combination, 3.1-fold, P < .01; 3.4-fold, P < .001; and 3.6-fold, P < .001 vs controls, respectively) and then declined after 8 weeks. The combination was more effective in inducing total NOS3 expression when compared to the separate drugs (1.4-fold; P < .05). Importantly, expression of NOS3 was associated with increased plasma NO levels and positively correlated with thoracic aorta relaxation. No changes in expression of NOS2 and AGTRL1a were observed. We showed that low-dose atorvastatin or losartan and especially their combination increases the expression of NOS3 and decreases the expression of EDNRA. These findings are valuable in explaining the effectiveness of the "low-dose pharmacological approach" for improvement in arterial function.

Effect of two oral contraceptives with different ethinyl estradiol and levonorgestrel concentrations on the urinary excretion of biochemical vasoactive markers.

PubMed

Mueck, A O; Seeger, H; Petersen, G; Schulte-Wintrop, E; Wallwiener, D

2001-12-01

In the present study the effect on the urinary excretion of vasoactive markers of two oral contraceptives (OCs), i.e., Leios, containing 0.02 mg ethinyl estradiol and 0.1 mg levonorgestrel, and Stediril 30, containing 0.03 mg ethinyl estradiol and 0.15 mg levonorgestrel, was investigated. cGMP, prostacyclin and its antagonist thromboxane, serotonin, and urodilatin, a natriuretic and diuretic peptide formed in the kidney, were measured as markers. In a comparative, double-blind, randomized, parallel group study, 34 women received Leios and 33 women Stediril 30. Nocturnal urine was collected before treatment and during cyclic treatment after 3 and 12 cycles. Both contraceptives significantly enhanced cGMP excretion after 12 cycles. The prostacyclin metabolite remained unchanged for both formulations, but the excretion of the thromboxane metabolite was significantly decreased after 12 cycles. Thus, the ratio of prostacyclin to thromboxane, crucial for the resulting effect on vascular tone, increased significantly. For the serotonin metabolite, no changes were observed for both contraceptives. The excretion of urodilatin significantly increased for both preparations after 12 cycles compared to the pretreatment values. These results indicate that the low-dose OCs Leios and Stediril 30 may stimulate the production of some vasoactive markers, at least after 12 cycles of treatment. The positive influence of these contraceptives on the various markers investigated may improve vascular tone, impede development of atherosclerosis and arterial thrombosis, and improve water and electrolyte homeostasis. These effects most likely can be attributed to the estrogenic component. Levonorgestrel may elicit no impact on these estrogen-induced changes that, however, seem only to be manifested after a longer treatment period.

Clinical significance of serum cortisol levels following surgery for congenital heart disease.

PubMed

Teagarden, Alicia M; Mastropietro, Christopher W

2017-03-01

Use of hydrocortisone to treat refractory haemodynamic instability in patients recovering from surgery for congenital heart disease is common practice at many centres. We aimed to determine whether there is a relationship between total serum cortisol concentrations and haemodynamic response to this therapy. Material and methods We retrospectively reviewed patients <21 years who underwent cardiac surgery from 2011 to 2013, received hydrocortisone within 72 hours postoperatively, and had total serum cortisol measurements contemporaneous with its administration. Favourable responders were defined as patients in whom, at 24 hours after hydrocortisone initiation, either (1) systolic blood pressure was increased or unchanged and vasoactive-inotrope score was decreased or (2) systolic blood pressure increased by ⩾10% of baseline and vasoactive-inotrope score was unchanged. Variables were compared using t-tests or Mann-Whitney U tests as appropriate. In total, 24 patients were reviewed, with a median age of 1.4 months and range of 0.1-232 months. Among them, 14 (58%) patients responded favourably to hydrocortisone. At 24 hours, the median change in vasoactive-inotrope score was -18% in favourable responders and +31% in those who did not respond favourably, p=0.001. The mean pre-hydrocortisone total serum cortisol in favourable responders was 17.4±10.9 µg/dl compared with 46.1±44.7 µg/dl in those who did not respond favourably, p=0.03. Total serum cortisol obtained before initiation of hydrocortisone was significantly lower in patients who responded favourably to this therapy. Total serum cortisol may therefore be helpful in identifying children recovering from cardiac surgery who may or may not haemodynamically improve with hydrocortisone.

Global epidemiology of pediatric severe sepsis: the sepsis prevalence, outcomes, and therapies study.

PubMed

Weiss, Scott L; Fitzgerald, Julie C; Pappachan, John; Wheeler, Derek; Jaramillo-Bustamante, Juan C; Salloo, Asma; Singhi, Sunit C; Erickson, Simon; Roy, Jason A; Bush, Jenny L; Nadkarni, Vinay M; Thomas, Neal J

2015-05-15

Limited data exist about the international burden of severe sepsis in critically ill children. To characterize the global prevalence, therapies, and outcomes of severe sepsis in pediatric intensive care units to better inform interventional trials. A point prevalence study was conducted on 5 days throughout 2013-2014 at 128 sites in 26 countries. Patients younger than 18 years of age with severe sepsis as defined by consensus criteria were included. Outcomes were severe sepsis point prevalence, therapies used, new or progressive multiorgan dysfunction, ventilator- and vasoactive-free days at Day 28, functional status, and mortality. Of 6,925 patients screened, 569 had severe sepsis (prevalence, 8.2%; 95% confidence interval, 7.6-8.9%). The patients' median age was 3.0 (interquartile range [IQR], 0.7-11.0) years. The most frequent sites of infection were respiratory (40%) and bloodstream (19%). Common therapies included mechanical ventilation (74% of patients), vasoactive infusions (55%), and corticosteroids (45%). Hospital mortality was 25% and did not differ by age or between developed and resource-limited countries. Median ventilator-free days were 16 (IQR, 0-25), and vasoactive-free days were 23 (IQR, 12-28). Sixty-seven percent of patients had multiorgan dysfunction at sepsis recognition, with 30% subsequently developing new or progressive multiorgan dysfunction. Among survivors, 17% developed at least moderate disability. Sample sizes needed to detect a 5-10% absolute risk reduction in outcomes within interventional trials are estimated between 165 and 1,471 [corrected] patients per group. Pediatric severe sepsis remains a burdensome public health problem, with prevalence, morbidity, and mortality rates similar to those reported in critically ill adult populations. International clinical trials targeting children with severe sepsis are warranted.

46 CFR 190.07-90 - Vessels contracted for prior to March 1, 1968.

Code of Federal Regulations, 2010 CFR

2010-10-01

... considered satisfactory so long as they are maintained in good condition to the satisfaction of the Officer in Charge, Marine Inspection. Minor repairs and alterations may be made to the same standards as the... VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 190.07-90 Vessels contracted for prior...

46 CFR 190.01-90 - Vessels contracted for prior to March 1, 1968.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Section 190.01-90 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Hull Structure § 190.01-90 Vessels contracted for prior to March 1... and alterations may be made to the same standards as the original construction. (b) Conversions, major...

Hierarchical and coupling model of factors influencing vessel traffic flow.

PubMed

Liu, Zhao; Liu, Jingxian; Li, Huanhuan; Li, Zongzhi; Tan, Zhirong; Liu, Ryan Wen; Liu, Yi

2017-01-01

Understanding the characteristics of vessel traffic flow is crucial in maintaining navigation safety, efficiency, and overall waterway transportation management. Factors influencing vessel traffic flow possess diverse features such as hierarchy, uncertainty, nonlinearity, complexity, and interdependency. To reveal the impact mechanism of the factors influencing vessel traffic flow, a hierarchical model and a coupling model are proposed in this study based on the interpretative structural modeling method. The hierarchical model explains the hierarchies and relationships of the factors using a graph. The coupling model provides a quantitative method that explores interaction effects of factors using a coupling coefficient. The coupling coefficient is obtained by determining the quantitative indicators of the factors and their weights. Thereafter, the data obtained from Port of Tianjin is used to verify the proposed coupling model. The results show that the hierarchical model of the factors influencing vessel traffic flow can explain the level, structure, and interaction effect of the factors; the coupling model is efficient in analyzing factors influencing traffic volumes. The proposed method can be used for analyzing increases in vessel traffic flow in waterway transportation system.

Hierarchical and coupling model of factors influencing vessel traffic flow

PubMed Central

Liu, Jingxian; Li, Huanhuan; Li, Zongzhi; Tan, Zhirong; Liu, Ryan Wen; Liu, Yi

2017-01-01

Understanding the characteristics of vessel traffic flow is crucial in maintaining navigation safety, efficiency, and overall waterway transportation management. Factors influencing vessel traffic flow possess diverse features such as hierarchy, uncertainty, nonlinearity, complexity, and interdependency. To reveal the impact mechanism of the factors influencing vessel traffic flow, a hierarchical model and a coupling model are proposed in this study based on the interpretative structural modeling method. The hierarchical model explains the hierarchies and relationships of the factors using a graph. The coupling model provides a quantitative method that explores interaction effects of factors using a coupling coefficient. The coupling coefficient is obtained by determining the quantitative indicators of the factors and their weights. Thereafter, the data obtained from Port of Tianjin is used to verify the proposed coupling model. The results show that the hierarchical model of the factors influencing vessel traffic flow can explain the level, structure, and interaction effect of the factors; the coupling model is efficient in analyzing factors influencing traffic volumes. The proposed method can be used for analyzing increases in vessel traffic flow in waterway transportation system. PMID:28414747

notch3 is essential for oligodendrocyte development and vascular integrity in zebrafish

PubMed Central

Zaucker, Andreas; Mercurio, Sara; Sternheim, Nitzan; Talbot, William S.; Marlow, Florence L.

2013-01-01

SUMMARY Mutations in the human NOTCH3 gene cause CADASIL syndrome (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy). CADASIL is an inherited small vessel disease characterized by diverse clinical manifestations including vasculopathy, neurodegeneration and dementia. Here we report two mutations in the zebrafish notch3 gene, one identified in a previous screen for mutations with reduced expression of myelin basic protein (mbp) and another caused by a retroviral insertion. Reduced mbp expression in notch3 mutant embryos is associated with fewer oligodendrocyte precursor cells (OPCs). Despite an early neurogenic phenotype, mbp expression recovered at later developmental stages and some notch3 homozygous mutants survived to adulthood. These mutants, as well as adult zebrafish carrying both mutant alleles together, displayed a striking stress-associated accumulation of blood in the head and fins. Histological analysis of mutant vessels revealed vasculopathy, including: an enlargement (dilation) of vessels in the telencephalon and fin, disorganization of the normal stereotyped arrangement of vessels in the fin, and an apparent loss of arterial morphological structure. Expression of hey1, a well-known transcriptional target of Notch signaling, was greatly reduced in notch3 mutant fins, suggesting that Notch3 acts via a canonical Notch signaling pathway to promote normal vessel structure. Ultrastructural analysis confirmed the presence of dilated vessels in notch3 mutant fins and revealed that the vessel walls of presumed arteries showed signs of deterioration. Gaps in the arterial wall and the presence of blood cells outside of vessels in mutants indicated that compromised vessel structure led to hemorrhage. In notch3 heterozygotes, we found elevated expression of both notch3 itself and target genes, indicating that specific alterations in gene expression due to partial loss of Notch3 function might contribute to the abnormalities observed in heterozygous larvae and adults. Our analysis of zebrafish notch3 mutants indicates that Notch3 regulates OPC development and mbp gene expression in larvae, and maintains vascular integrity in adults. PMID:23720232

Impact of a structured ICU training programme in resource-limited settings in Asia.

PubMed

Haniffa, Rashan; Lubell, Yoel; Cooper, Ben S; Mohanty, Sanjib; Alam, Shamsul; Karki, Arjun; Pattnaik, Rajya; Maswood, Ahmed; Haque, R; Pangeni, Raju; Schultz, Marcus J; Dondorp, Arjen M

2017-01-01

To assess the impact on ICU performance of a modular training program in three resource-limited general adult ICUs in India, Bangladesh, and Nepal. A modular ICU training programme was evaluated using performance indicators from June 2009 to June 2012 using an interrupted time series design with an 8 to 15 month pre-intervention and 18 to 24 month post-intervention period. ICU physicians and nurses trained in Europe and the USA provided training for ICU doctors and nurses. The training program consisted of six modules on basic intensive care practices of 2-3 weeks each over 20 months. The performance indicators consisting of ICU mortality, time to ICU discharge, rate at which patients were discharged alive from the ICU, discontinuation of mechanical ventilation or vasoactive drugs and duration of antibiotic use were extracted. Stepwise changes and changes in trends associated with the intervention were analysed. Pre-Training ICU mortality in Rourkela (India), and Patan (Nepal) Chittagong (Bangladesh), was 28%, 41% and 62%, respectively, compared to 30%, 18% and 51% post-intervention. The intervention was associated with a stepwise reduction in cumulative incidence of in-ICU mortality in Chittagong (adjusted subdistribution hazard ratio [aSHR] (95% CI): 0.62 (0.40, 0.97), p = 0.03) and Patan (aSHR 0.16 (0.06, 0.41), p<0.001), but not in Rourkela (aSHR: 1.17 (0.75, 1.82), p = 0.49). The intervention was associated with earlier discontinuation of vasoactive drugs at Rourkela (adjusted hazard ratio for weekly change [aHR] 1.08 (1.03, 1.14), earlier discontinuation of mechanical ventilation in Chittagong (aHR 2.97 (1.24, 7.14), p = 0.02), and earlier ICU discharge in Patan (aHR 1.87 (1.02, 3.43), p = 0.04). This structured training program was associated with a decrease in ICU mortality in two of three sites and improvement of other performance indicators. A larger cluster randomised study assessing process outcomes and longer-term indicators is warranted.

Developing a method of fabricating microchannels using plant root structure

NASA Astrophysics Data System (ADS)

Nakashima, Shota; Tokumaru, Kazuki; Tsumori, Fujio

2018-06-01

Complicated three-dimensional (3D) microchannels are expected to be applied to a lab-on-a-chip, especially an organ-on-a-chip. There are fine microchannel networks such as blood vessels in a living organ. However, it is difficult to recreate the complicated 3D microchannels of real living structures. Plant roots have a similar structure to blood vessels. They spread radially and three-dimensionally, and become thinner as they branch. In this research, we propose a method of fabricating microchannels using a live plant root as a template to mimic a blood vessel structure. We grew a plant in ceramic slurry instead of soil. The slurry consists of ceramic powder, binder and water, so it plays a similar role to soil consisting of fine particles in water. After growing the plant, the roots inside the slurry were burned and a sintered ceramic body with channel structures was obtained by heating. We used two types of slurry with different composition ratios, and compared the internal channel structures before and after sintering.

Optical clearing of the pancreas for visualization of mature β-cells and vessels in mice.

PubMed

Nishimura, Wataru; Sakaue-Sawano, Asako; Takahashi, Satoru; Miyawaki, Atsushi; Yasuda, Kazuki; Noda, Yasuko

2018-05-04

Glucose metabolism is regulated by insulin, which is produced from β-cells in the pancreas. Because insulin is secreted into vessels in response to blood glucose, vascular structures of the pancreas, especially the relationship between vessels and β-cells, are important for physiological and pathological glucose metabolism. Here, we developed a system to visualize vessels surrounding mature β-cells expressing transcription factor MafA in a three-dimensional manner. Optical clearing of the pancreas prevented light scattering of fluorescence driven by the bacterial artificial chromosome (BAC)-mafA promoter in β-cells. Reconstruction of confocal images demonstrated mature β-cells and the glomerular-like structures of β-cell vasculatures labeled with DyLight 488-conjugated lectin in normal mice as well as in low-dose streptozotocin-injected diabetes model mice with reduced β-cell mass. This technological innovation of organ imaging can be used to investigate morphological changes in vascular structures during transplantation, regeneration and diabetes development.

Vasoactive intestinal peptide and electrical activity influence neuronal survival

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

Brenneman, D.E.; Eiden, L.E.

1986-02-01

Blockage of electrical activity in dissociated spinal cord cultures results in a significant loss of neurons during a critical period in development. Decreases in neuronal cell numbers and SVI-labeled tetanus toxin fixation produced by electrical blockage with tetrodotoxin (TTX) were prevented by addition of vasoactive intestinal peptide (VIP) to the nutrient medium. The most effective concentration of VIP was 0.1 nM. At higher concentrations, the survival-enhancing effect of VIP on TTX-treated cultures was attenuated. Addition of the peptide alone had no significant effect on neuronal cell counts or tetanus toxin fixation. With the same experimental conditions, two closely related peptides,more » PHI-27 (peptide, histidyl-isoleucine amide) and secretin, were found not to increase the number of neurons in TTX-treated cultures. Interference with VIP action by VIP antiserum resulted in neuronal losses that were not significantly different from those observed after TTX treatment. These data indicate that under conditions of electrical blockade a neurotrophic action of VIP on neuronal survival can be demonstrated.« less

Contributions of mast cells and vasoactive products, leukotrienes and chymase, to dengue virus-induced vascular leakage

PubMed Central

St John, Ashley L; Rathore, Abhay PS; Raghavan, Bhuvanakantham; Ng, Mah-Lee; Abraham, Soman N

2013-01-01

Dengue Virus (DENV), a flavivirus spread by mosquito vectors, can cause vascular leakage and hemorrhaging. However, the processes that underlie increased vascular permeability and pathological plasma leakage during viral hemorrhagic fevers are largely unknown. Mast cells (MCs) are activated in vivo during DENV infection, and we show that this elevates systemic levels of their vasoactive products, including chymase, and promotes vascular leakage. Treatment of infected animals with MC-stabilizing drugs or a leukotriene receptor antagonist restores vascular integrity during experimental DENV infection. Validation of these findings using human clinical samples revealed a direct correlation between MC activation and DENV disease severity. In humans, the MC-specific product, chymase, is a predictive biomarker distinguishing dengue fever (DF) and dengue hemorrhagic fever (DHF). Additionally, our findings reveal MCs as potential therapeutic targets to prevent DENV-induced vasculopathy, suggesting MC-stabilizing drugs should be evaluated for their effectiveness in improving disease outcomes during viral hemorrhagic fevers. DOI: http://dx.doi.org/10.7554/eLife.00481.001 PMID:23638300

Tissue oxygen demand in regulation of the behavior of the cells in the vasculature.

PubMed

Barvitenko, Nadezhda N; Aslam, Muhammad; Filosa, Jessica; Matteucci, Elena; Nikinmaa, Mikko; Pantaleo, Antonella; Saldanha, Carlota; Baskurt, Oguz K

2013-08-01

The control of arteriolar diameters in microvasculature has been in the focus of studies on mechanisms matching oxygen demand and supply at the tissue level. Functionally, important vascular elements include EC, VSMC, and RBC. Integration of these different cell types into functional units aimed at matching tissue oxygen supply with tissue oxygen demand is only achieved when all these cells can respond to the signals of tissue oxygen demand. Many vasoactive agents that serve as signals of tissue oxygen demand have their receptors on all these types of cells (VSMC, EC, and RBC) implying that there can be a coordinated regulation of their behavior by the tissue oxygen demand. Such functions of RBC as oxygen carrying by Hb, rheology, and release of vasoactive agents are considered. Several common extra- and intracellular signaling pathways that link tissue oxygen demand with control of VSMC contractility, EC permeability, and RBC functioning are discussed. © 2013 John Wiley & Sons Ltd.

Phorbol esters alter adenylate cyclase responses to vasoactive intestinal peptide and forskolin in the GH cell line

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

Summers, S.; Florio, T.; Cronin, M.

1986-05-01

Activation of protein kinase C with phorbol ester modifies cyclic AMP production in several anterior pituitary cell systems. In the GH cell line from a rat pituitary tumor, exposure to phorbol 12-myristate 13-acetate (PMA: 100 nM) for 30 minutes significantly reduces vasoactive intestinal peptide (VIP: 100 nM) stimulated adenylate cyclase (AC) activity in subsequent membrane preparations to 62 + 4% of control (n = 6 independent studies). In contrast, these same membrane preparations respond to forskolin (1 ..mu..M) with significantly more activity, 130 +/- 6% of controls (n = 6 independent studies). Finally, phorbol ester does not block an inhibitorymore » hormone input into the AC system; somatostatin (100 nM) reduction of VIP-stimulated AC activity is not significantly different in membrane preparations from PMA treated and control cells (n = 3 independent studies). These other findings lead the authors to propose that protein kinase C can modify several sites in the AC complex in anterior pituitary cells.« less

Hippocampal asymmetry in exploratory behavior to vasoactive intestinal polypeptide.

PubMed

Ivanova, Margarita; Ternianov, Alexandar; Belcheva, Stiliana; Tashev, Roman; Negrev, Negrin; Belcheva, Iren

2008-06-01

The effects of vasoactive intestinal polypeptide (VIP) microinjected uni- or bilaterally into the CA1 hippocampal area of male Wistar rats at a dose of 10, 50 and 100 ng on exploratory behavior were examined. VIP microinjected bilaterally at a high dose (100 ng) significantly decreased the horizontal movements, while at low doses (10 and 50 ng) had no effect on the exploratory activity. Microinjections of VIP into the left hippocampal CA1 area at doses 50 and 100 ng suppressed the exploratory activity, while right-side VIP administration at a dose 100 ng significantly increased horizontal movements compared to the respective controls. Vertical activity was stimulated only by VIP administered into the right hippocampal CA1 area at the three doses used. Neither bilateral nor left injections of VIP induced changes in the vertical movements. The main finding was the presence of hippocampal asymmetry in exploratory behavior to unilateral microinjections of VIP depending on the dose and the microinjected hemisphere.

Pancreatic cholera syndrome: effect of a synthetic somatostatin analog on intestinal water and ion transport.

PubMed

Santangelo, W C; O'Dorisio, T M; Kim, J G; Severino, G; Krejs, G J

1985-09-01

The effect of a synthetic somatostatin analog was studied in a patient with severe secretory diarrhea due to pancreatic cholera syndrome. Basal intestinal perfusion studies indicated an absence of water and sodium absorption, and active chloride secretion in the small bowel. Intravenous administration of the somatostatin analog (1 microgram/kg.h) changed zero net water movement to absorption (122 mL/30 cm of the jejunum per hour). Chloride secretion changed to absorption (5.0 to 7.9 meq/30 cm.h), and plasma vasoactive intestinal polypeptide concentration was reduced from 330 to 45 pmol/L (normal, less than 51). When the analog was given subcutaneously, 100 micrograms twice daily, stool weight decreased, and plasma vasoactive intestinal polypeptide concentration fell toward the normal range (67 pmol/L). Plasma concentration of pancreatic polypeptide was initially elevated and dropped during intravenous infusion of somatostatin analog but returned to baseline on maintenance therapy with the analog delivered subcutaneously. The patient has not had further diarrhea during 9 months of therapy.

Mediation of the vasoactive properties of diadenosine tetraphosphate via various purinoceptors.

PubMed

van der Giet, M; Jankowski, J; Schlüter, H; Zidek, W; Tepel, M

1998-12-01

The vasoactive properties of P1,P4-diadenosine tetraphosphate (Ap4A) were studied by measuring the effects of perfusion pressure of a rat isolated perfused kidney. The vasoconstrictive response to Ap4A was mediated to a large extent to a P2X receptor which could be shown by inhibition with pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid tetrasodium. The remaining vasoconstriction of Ap4A could be blocked by a 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a selective A1 receptor antagonist In raised tone preparation Ap4A evoked vasodilation when P2 receptors were blocked by suramin. The dilation was not mediated by a P2Y receptor as the effect could not be blocked by suramin. Ap4A induces vasoconstriction via A1 and P2X receptors and vasodilatation via an unidentified receptor which is not a P2Y receptor. Ap4A may play an important role in kidney perfusion and, thus, in blood-pressure control.

Vasoactive intestinal peptide prevents lung injury due to xanthine/xanthine oxidase.

PubMed

Berisha, H; Foda, H; Sakakibara, H; Trotz, M; Pakbaz, H; Said, S I

1990-08-01

Reactive oxygen species mediate injury and inflammation in many tissues. The addition of xanthine and xanthine oxidase to perfused rat lungs led to increases in peak airway pressure and perfusion pressure, pulmonary edema, and increased protein content in bronchoalveolar lavage fluid. Treatment with 1-10 micrograms.kg-1.min-1 of vasoactive intestinal peptide (VIP), a widely distributed neuropeptide, markedly reduced or totally prevented all signs of injury. Simultaneously, VIP also diminished or abolished the associated generation of arachidonate products. Similar protection was provided by catalase (100 micrograms/ml) but not by the VIP-related peptides secretin or glucagon. The pulmonary vasodilator papaverine (0.15 mg/ml) was also ineffective. Injured lungs that were not treated with VIP released large amounts of this peptide in the perfusate. The results indicate that VIP has potent protective activity against injury triggered by xanthine/xanthine oxidase and may be a physiological modulator of inflammatory tissue damage associated with toxic oxygen metabolites.

Intuitive parameter-free visualization of tumor vascularization using rotating connectivity projections

NASA Astrophysics Data System (ADS)

Wiemker, Rafael; Bülow, Thomas; Opfer, Roland; Kabus, Sven; Dharaiya, Ekta

2008-03-01

We present an effective and intuitive visualization of the macro-vasculature of a selected nodule or tumor in three-dimensional image data (e.g. CT, MR, US). For the differential diagnosis of nodules the possible distortion of adjacent vessels is one important clinical criterion. Surface renderings of vessel- and tumor-segmentations depend critically on the chosen parameter- and threshold-values for the underlying segmentation. Therefore we use rotating Maximum Intensity Projections (MIPs) of a volume of interests (VOI) around the selected tumor. The MIP does not require specific parameters, and allows much quicker visual inspection in comparison to slicewise navigation, while the rotation gives depth cues to the viewer. Of the vessel network within the VOI, however, not all vessels are connected to the selected tumor, and it is tedious to sort out which adjacent vessels are in fact connected and which are overlaid only by projection. Therefore we suggest a simple transformation of the original image values into connectivity values. In the derived connectedness-image each voxel value corresponds to the lowest image value encountered on the highest possible pathway from the tumor to the voxel. The advantage of the visualization is that no implicit binary decision is made whether a certain vessel is connected to the tumor or not, but rather the degree of connectedness is visualized as the brightness of the vessel. Non-connected structures disappear, feebly connected structures appear faint, and strongly connected structures remain in their original brightness. The visualization does not depend on delicate threshold values. Promising results have been achieved for pulmonary nodules in CT.

46 CFR 177.315 - Vessels of not more than 19.8 meters (65 feet) in length carrying not more than 12 passengers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Vessels of not more than 19.8 meters (65 feet) in length... Structure § 177.315 Vessels of not more than 19.8 meters (65 feet) in length carrying not more than 12 passengers. The scantlings for a vessel of not more than 19.8 meters (65 feet) in length carrying not more...

46 CFR 177.315 - Vessels of not more than 19.8 meters (65 feet) in length carrying not more than 12 passengers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Vessels of not more than 19.8 meters (65 feet) in length... Structure § 177.315 Vessels of not more than 19.8 meters (65 feet) in length carrying not more than 12 passengers. The scantlings for a vessel of not more than 19.8 meters (65 feet) in length carrying not more...

A robust technique based on VLM and Frangi filter for retinal vessel extraction and denoising.

PubMed

Khan, Khan Bahadar; Khaliq, Amir A; Jalil, Abdul; Shahid, Muhammad

2018-01-01

The exploration of retinal vessel structure is colossally important on account of numerous diseases including stroke, Diabetic Retinopathy (DR) and coronary heart diseases, which can damage the retinal vessel structure. The retinal vascular network is very hard to be extracted due to its spreading and diminishing geometry and contrast variation in an image. The proposed technique consists of unique parallel processes for denoising and extraction of blood vessels in retinal images. In the preprocessing section, an adaptive histogram equalization enhances dissimilarity between the vessels and the background and morphological top-hat filters are employed to eliminate macula and optic disc, etc. To remove local noise, the difference of images is computed from the top-hat filtered image and the high-boost filtered image. Frangi filter is applied at multi scale for the enhancement of vessels possessing diverse widths. Segmentation is performed by using improved Otsu thresholding on the high-boost filtered image and Frangi's enhanced image, separately. In the postprocessing steps, a Vessel Location Map (VLM) is extracted by using raster to vector transformation. Postprocessing steps are employed in a novel way to reject misclassified vessel pixels. The final segmented image is obtained by using pixel-by-pixel AND operation between VLM and Frangi output image. The method has been rigorously analyzed on the STARE, DRIVE and HRF datasets.

Focusing particle concentrator with application to ultrafine particles

DOEpatents

Hering, Susanne; Lewis, Gregory; Spielman, Steven R.

2013-06-11

Technology is presented for the high efficiency concentration of fine and ultrafine airborne particles into a small fraction of the sampled airflow by condensational enlargement, aerodynamic focusing and flow separation. A nozzle concentrator structure including an acceleration nozzle with a flow extraction structure may be coupled to a containment vessel. The containment vessel may include a water condensation growth tube to facilitate the concentration of ultrafine particles. The containment vessel may further include a separate carrier flow introduced at the center of the sampled flow, upstream of the acceleration nozzle of the nozzle concentrator to facilitate the separation of particle and vapor constituents.

46 CFR Appendix A to Part 109 - Navigation and Vessel Inspection Circular No. 4-78-Inspection and Certification of Existing...

Code of Federal Regulations, 2011 CFR

2011-10-01

...” designed and operated to carry out an industrial function at sea. Contemporary U.S. Vessel regulations in... structural designs, industrial equipment and operating procedures incorporated in drilling vessels. To... meet reasonable levels of safety. To this end, the following determinations will be made: • The design...

46 CFR Appendix A to Part 109 - Navigation and Vessel Inspection Circular No. 4-78-Inspection and Certification of Existing...

Code of Federal Regulations, 2014 CFR

2014-10-01

...” designed and operated to carry out an industrial function at sea. Contemporary U.S. Vessel regulations in... structural designs, industrial equipment and operating procedures incorporated in drilling vessels. To... meet reasonable levels of safety. To this end, the following determinations will be made: • The design...

46 CFR Appendix A to Part 109 - Navigation and Vessel Inspection Circular No. 4-78-Inspection and Certification of Existing...

Code of Federal Regulations, 2013 CFR

2013-10-01

...” designed and operated to carry out an industrial function at sea. Contemporary U.S. Vessel regulations in... structural designs, industrial equipment and operating procedures incorporated in drilling vessels. To... meet reasonable levels of safety. To this end, the following determinations will be made: • The design...

46 CFR Appendix A to Part 109 - Navigation and Vessel Inspection Circular No. 4-78-Inspection and Certification of Existing...

Code of Federal Regulations, 2012 CFR

2012-10-01

...” designed and operated to carry out an industrial function at sea. Contemporary U.S. Vessel regulations in... structural designs, industrial equipment and operating procedures incorporated in drilling vessels. To... meet reasonable levels of safety. To this end, the following determinations will be made: • The design...

46 CFR Appendix A to Part 109 - Navigation and Vessel Inspection Circular No. 4-78-Inspection and Certification of Existing...

Code of Federal Regulations, 2010 CFR

2010-10-01

...” designed and operated to carry out an industrial function at sea. Contemporary U.S. Vessel regulations in... structural designs, industrial equipment and operating procedures incorporated in drilling vessels. To... meet reasonable levels of safety. To this end, the following determinations will be made: • The design...

Novel method for edge detection of retinal vessels based on the model of the retinal vascular network and mathematical morphology

NASA Astrophysics Data System (ADS)

Xu, Lei; Zheng, Xiaoxiang; Zhang, Hengyi; Yu, Yajun

1998-09-01

Accurate edge detection of retinal vessels is a prerequisite for quantitative analysis of subtle morphological changes of retinal vessels under different pathological conditions. A novel method for edge detection of retinal vessels is presented in this paper. Methods: (1) Wavelet-based image preprocessing. (2) The signed edge detection algorithm and mathematical morphological operation are applied to get the approximate regions that contain retinal vessels. (3) By convolving the preprocessed image with a LoG operator only on the detected approximate regions of retinal vessels, followed by edges refining, clear edge maps of the retinal vessels are fast obtained. Results: A detailed performance evaluation together with the existing techniques is given to demonstrate the strong features of our method. Conclusions: True edge locations of retinal vessels can be fast detected with continuous structures of retinal vessels, less non- vessel segments left and insensitivity to noise. The method is also suitable for other application fields such as road edge detection.

Assembly & Metrology of First Wall Components of SST-1

NASA Astrophysics Data System (ADS)

Parekh, Tejas; Santra, Prosenjit; Biswas, Prabal; Patel, Hiteshkumar; Paravastu, Yuvakiran; Jaiswal, Snehal; Chauhan, Pradeep; Babu, Gattu Ramesh; A, Arun Prakash; Bhavsar, Dhaval; Raval, Dilip C.; Khan, Ziauddin; Pradhan, Subrata

2017-04-01

First Wall Components (FWC) of SST-1 tokamak, which are in the immediate vicinity of plasma comprises of limiters, divertors, baffles, passive stabilizers are designed to operate long duration (1000 s) discharges of elongated plasma. All FWC consists of a copper alloy heat sink modules with SS cooling tubes brazed onto it, graphite tiles acting as armour material facing the plasma, and are mounted to the vacuum vessels with suitable Inconel support structures at ring & port locations. The FWC are very recently assembled and commissioned successfully inside the vacuum vessel of SST-1 undergoing a meticulous planning of assembly sequence, quality checks at every stage of the assembly process. This paper will present the metrology aspects & procedure of each FWC, both outside the vacuum vessel, and inside the vessel, assembly tolerances, tools, equipment and jig/fixtures, used at each stage of assembly, starting from location of support bases on vessel rings, fixing of copper modules on support structures, around 3800 graphite tile mounting on 136 copper modules with proper tightening torques, till final toroidal and poloidal geometry of the in-vessel components are obtained within acceptable limits, also ensuring electrical continuity of passive stabilizers to form a closed saddle loop, electrical isolation of passive stabilizers from vacuum vessel.

MicroCT angiography detects vascular formation and regression in skin wound healing.

PubMed

Urao, Norifumi; Okonkwo, Uzoagu A; Fang, Milie M; Zhuang, Zhen W; Koh, Timothy J; DiPietro, Luisa A

2016-07-01

Properly regulated angiogenesis and arteriogenesis are essential for effective wound healing. Tissue injury induces robust new vessel formation and subsequent vessel maturation, which involves vessel regression and remodeling. Although formation of functional vasculature is essential for healing, alterations in vascular structure over the time course of skin wound healing are not well understood. Here, using high-resolution ex vivo X-ray micro-computed tomography (microCT), we describe the vascular network during healing of skin excisional wounds with highly detailed three-dimensional (3D) reconstructed images and associated quantitative analysis. We found that relative vessel volume, surface area and branching number are significantly decreased in wounds from day 7 to days 14 and 21. Segmentation and skeletonization analysis of selected branches from high-resolution images as small as 2.5μm voxel size show that branching orders are decreased in the wound vessels during healing. In histological analysis, we found that the contrast agent fills mainly arterioles, but not small capillaries nor large veins. In summary, high-resolution microCT revealed dynamic alterations of vessel structures during wound healing. This technique may be useful as a key tool in the study of the formation and regression of wound vessels. Copyright © 2016 Elsevier Inc. All rights reserved.

Feasibility evaluation of 3D photoacoustic imaging of blood vessel structure using multiple wavelengths with a handheld probe

NASA Astrophysics Data System (ADS)

Uchimoto, Yo; Namita, Takeshi; Kondo, Kengo; Yamakawa, Makoto; Shiina, Tsuyoshi

2018-02-01

Photoacoustic imaging is anticipated for use in portraying blood vessel structures (e.g. neovascularization in inflamed regions). To reduce invasiveness and enhance ease handling, we developed a handheld photoacoustic imaging system using multiple wavelengths. The usefulness of the proposed system was investigated in phantom experiments and in vivo measurements. A silicon tube was embedded into chicken breast meat to simulate the blood vessel. The tube was filled with ovine blood. Then laser light was guided to the phantom surface by an optical fiber bundle close to the linear ultrasound probe. Photoacoustic images were obtained at 750-950 nm wavelengths. Strong photoacoustic signals from the boundary between blood and silicon tube are observed in these images. The shape of photoacoustic spectrum at the boundary resembles that of the HbO2 absorption spectrum at 750-920 nm. In photoacoustic images, similarity between photoacoustic spectrum and HbO2 absorption spectrum was evaluated by calculating the normalized correlation coefficient. Results show high correlation in regions of strong photoacoustic signals in photoacoustic images. These analyses demonstrate the feasibility of portraying blood vessel structures under practical conditions. To evaluate the feasibility of three-dimensional vascular imaging, in vivo experiments were conducted using three wavelengths. A right hand and ultrasound probe were set in degassed water. By scanning a probe, cross-sectional ultrasound and photoacoustic images were obtained at each location. Then, all ultrasound or photoacoustic images were piled up respectively. Then three-dimensional images were constructed. Resultant images portrayed blood vessel-like structures three-dimensionally. Furthermore, to distinguish blood vessels from other tissues (e.g. skin), distinguishing images of them were constructed by comparing photoacoustic signal intensity among three wavelengths. The resultant image portrayed blood vessels as distinguished from surrounding tissues. These results demonstrated the usefulness of the proposed imaging device.

Endophyte-infected tall fescue seed extract induces constriction of bovine vasculature

USDA-ARS?s Scientific Manuscript database

Ergovaline (ERV) has been extensively used to study vasoactive effects of endophyte (Neotyphodium coenophialum) infected tall fescue (Lolium arundinaceum). However preliminary in vitro tests show that an extract of toxic tall fescue seed (E+EXT) is more potent than ERV alone indicating other compoun...

Nitroso-sulfide coupled signaling triggers specific vasoactive effects in the intrarenal arteries of patients with arterial hypertension.

PubMed

Cacanyiova, S; Berenyiova, A; Balis, P; Kristek, F; Grman, M; Ondrias, K; Breza, J; Breza, J

2017-08-01

In normotensive conditions, it has been confirmed that S-nitrosothiols (RSNO), can interact with hydrogen sulfide (H 2 S) and create new substances with specific vasoactive effects. This interaction could also represent a new regulator signaling pathway in conditions of hypertension. Until now, these effects were studied only in normotensive rats, and they have not been carried out in humans yet. We investigated the vasoactive effects of the products of the H 2 S/S-nitrosoglutathione (S/GSNO) interaction in lobar arteries (LA) isolated from the nephrectomized kidneys of patients suffering from arterial hypertension and in renal arteries (RA) of spontaneously hypertensive rats (SHR). The changes in the isometric tension of pre-contracted arteries were evaluated. Acetylcholine-induced vasorelaxation of LA was reduced compared to the effect induced by an NO donor, sodium nitroprusside suggesting an endothelium dysfunction. While 1 μmol/L Na2S had a minimal effect on the vascular tone, the concentration 20 μmol/L evoked a slight vasorelaxation. GSNO at 0.1 μmol/L induced vasorelaxation, which was less pronounced compared to the effect induced by 1 μmol/L. The S/GSNO products (final concentration 0.1 μmol/L) prepared as the mixture of GSNO (0.1 μmol/L) + Na2S (1 μmol/L) induced a higher vasorelaxation compared to GSNO (0.1 μmol/L) alone only in the 5 th minute and without the differences in the speed. On the other hand, the S/GSNO products (final concentration 1 μmol/L) prepared as the mixture of GSNO (1 μmol/L) + Na2S (10 μmol/L) induced a higher and faster vasorelaxation compared to the effect induced by GSNO (1 μmol/L) alone. In RA of SHR this S/GSNO products induced similar vasorelaxation (higher and faster than GSNO) with involvement of HNO (partially) and cGMP as mediators. However, the products of the H 2 S/NO donor (DEA NONOate) manifested differently than S/GSNO indicating the unique interaction between GSNO and H 2 S. In this study, we confirmed for the first time that specific vasoactive effects of coupled nitroso-sulfide signaling were also triggered in human arterial tissue. We suggest that in hypertension, H 2 S in interaction with GSNO regulated a vasoconstrictor-induced increase in arterial tone towards a stronger vasorelaxation compared to GSNO alone or H 2 S alone.

Synergic nitrogen source route to inorganic fullerene-like boron nitride with vessel, hollow sphere, onion, and peanut nanostructures.

PubMed

Xu, Fen; Xie, Yi; Zhang, Xu; Zhang, Shuyuan; Liu, Xianming; Tian, Xiaobo

2004-01-26

In this paper we describe the large-scale synthesis of inorganic fullerene-like (IF-like) hexagonal boron nitride with vessel, hollow sphere, peanut, and onion structures by reacting BBr(3) with the synergic nitrogen sources NaNH(2) and NH(4)Cl at 400-450 degrees C for 6-12 h. The composition of products could be confirmed to be pure boron nitride with hexagonal structures by the XRD patterns and FT-IR, XPS, and EDXA spectra. The representative HRTEM images clearly reveal the layerlike features of the products. Here, the peanut-like structure of the IF-like BN is reported for the first time, and added to the list as one kind of new morphology of BN nanomaterials. The similarity in the structure between h-BN and graphite is responsible for the formation of IF-like BN with nanostructures of vessels, hollow spheres, peanuts, and onions.

Dual-Image Videoangiography During Intracranial Microvascular Surgery.

PubMed

Feletti, Alberto; Wang, Xiangdong; Tanaka, Riki; Yamada, Yasuhiro; Suyama, Daisuke; Kawase, Tsukasa; Sano, Hirotoshi; Kato, Yoko

2017-03-01

Indocyanine green videoangiography (ICG-VA) is a valuable tool to assess vessel and aneurysm patency during neurovascular surgical procedures. However, ICG-VA highlights vascular structures, which appear white over a black background. Anatomic relationships are sometimes difficult to understand at first glance. Dual-image videoangiography (DIVA) enables simultaneous visualization of light and near-infrared fluorescence images of ICG-VA. The DIVA system was mounted on an OPMI Pentero Flow 800 intraoperative microscope. DIVA was used during microsurgical procedures on 5 patients who were operated for aneurysm clipping and superficial temporal artery-middle cerebral artery bypass. DIVA provides real-time simultaneous visualization of aneurysm and vessels and surrounding structures including brain, nerves, and surgical clips. Although visual contrast between vessels and background is higher with standard black-and-white imaging, DIVA makes it easier to understand anatomic relationships between intracranial structures. DIVA also provides better vision of the depth of field. DIVA has the potential to become a widely used intraoperative tool to check patency of intracranial vessels. It should be considered as an adjunct to standard ICG-VA for better understanding of vascular anatomy in relation to surrounding structures and can have an impact on decision making during surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Design, Analysis and R&D of the EAST In-Vessel Components

NASA Astrophysics Data System (ADS)

Yao, Damao; Bao, Liman; Li, Jiangang; Song, Yuntao; Chen, Wenge; Du, Shijun; Hu, Qingsheng; Wei, Jing; Xie, Han; Liu, Xufeng; Cao, Lei; Zhou, Zibo; Chen, Junling; Mao, Xinqiao; Wang, Shengming; Zhu, Ning; Weng, Peide; Wan, Yuanxi

2008-06-01

In-vessel components are important parts of the EAST superconducting tokamak. They include the plasma facing components, passive plates, cryo-pumps, in-vessel coils, etc. The structural design, analysis and related R&D have been completed. The divertor is designed in an up-down symmetric configuration to accommodate both double null and single null plasma operation. Passive plates are used for plasma movement control. In-vessel coils are used for the active control of plasma vertical movements. Each cryo-pump can provide an approximately 45 m3/s pumping rate at a pressure of 10-1 Pa for particle exhaust. Analysis shows that, when a plasma current of 1 MA disrupts in 3 ms, the EM loads caused by the eddy current and the halo current in a vertical displacement event (VDE) will not generate an unacceptable stress on the divertor structure. The bolted divertor thermal structure with an active cooling system can sustain a load of 2 MW/m2 up to a 60 s operation if the plasma facing surface temperature is limited to 1500 °C. Thermal testing and structural optimization testing were conducted to demonstrate the analysis results.

46 CFR 32.70-5 - Hull requirements; general-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., AND HULL REQUIREMENTS Hull Requirements for Steel Hull Tank Vessels Constructed Prior to November 10... Charge, Marine Inspection, shall satisfy himself that the vessel's structure as specified in this section...

46 CFR 32.70-5 - Hull requirements; general-TB/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., AND HULL REQUIREMENTS Hull Requirements for Steel Hull Tank Vessels Constructed Prior to November 10... Charge, Marine Inspection, shall satisfy himself that the vessel's structure as specified in this section...

46 CFR 32.70-5 - Hull requirements; general-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., AND HULL REQUIREMENTS Hull Requirements for Steel Hull Tank Vessels Constructed Prior to November 10... Charge, Marine Inspection, shall satisfy himself that the vessel's structure as specified in this section...

46 CFR 32.70-5 - Hull requirements; general-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., AND HULL REQUIREMENTS Hull Requirements for Steel Hull Tank Vessels Constructed Prior to November 10... Charge, Marine Inspection, shall satisfy himself that the vessel's structure as specified in this section...

46 CFR 69.209 - Calculation of tonnages.

Code of Federal Regulations, 2010 CFR

2010-10-01

....67 LBD/100. (2) The gross tonnage of a vessel with a hull that approximates in shape a rectangular geometric solid (barge-shape) is 0.84 LBD/100. (3) The gross tonnage of a multi-hull vessel is the sum of... structure in tons of 100 cubic feet is added to the tonnage of the hull to establish the vessel's gross...

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.

Non-Axisymmetric Inflatable Pressure Structure (NAIPS) Concept that Enables Mass Efficient Packageable Pressure Vessels with Sealable Openings

NASA Technical Reports Server (NTRS)

Doggett, William R.; Jones, Thomas C.; Kenner, Winfred S.; Moore, David F.; Watson, Judith J.; Warren, Jerry E.; Makino, Alberto; Yount, Bryan; Selig, Molly; Shariff, Khadijah;

Interaction of isoflavones and endophyte-infected tall fescue seed extract on vasoactivity of bovine mesenteric vasculature

USDA-ARS?s Scientific Manuscript database

It was hypothesized that isoflavones may attenuate ergot alkaloid-induced vasoconstriction and possibly alleviate diminished contractility of vasculature after exposure to ergot alkaloids. The objective of this study was to determine if prior incubation of bovine mesenteric vasculature with the isof...

The Beauty and the Beast: Aspects of the Autonomic Nervous System.

PubMed

Corti, Roberto; Binggeli, Christian; Sudano, Isabella; Spieker, Lukas E.; Wenzel, René R.; Lüscher, Thomas F.; Noll, Georg

2000-06-01

Sympathetic nerve activity is altered and is a prognostic factor for many cardiovascular diseases such as hypertension, coronary syndromes, and congestive heart failure. Therefore, the selection of vasoactive drugs for the treatment of these diseases should also take into consideration their effects on the sympathetic nervous system.

Vasoactivity and vasoconstriction changes in cattle related to time off toxic endophyte-infected tall fescue

USDA-ARS?s Scientific Manuscript database

Previous research has indicated that serotonergic and a-adrenergic receptors in peripheral vasculature are affected by exposure of cattle grazing toxic endophyte-infected (E+; Epichlöe coenophialia) tall fescue (Lolium arundinaceum). The objective of this experiment was to determine the period of ti...

Pancreatic tumours produce neurotensin.

PubMed

Blackburn, A M; Bryant, M G; Adrian, T E; Bloom, S R

1981-04-01

Tumour tissue may secrete substances which are not normally secreted by the original tissue. We have found that 6 out of 21 pancreatic tumours producing vasoactive intestinal peptide also produce neurotensin-like peptides. These are sometimes secreted and very high plasma levels of neurotensin-like immunoreactivity may be found in the circulation.

Pressurized water reactor flow skirt apparatus

DOEpatents

Kielb, John F.; Schwirian, Richard E.; Lee, Naugab E.; Forsyth, David R.

2016-04-05

A pressurized water reactor vessel having a flow skirt formed from a perforated cylinder structure supported in the lower reactor vessel head at the outlet of the downcomer annulus, that channels the coolant flow through flow holes in the wall of the cylinder structure. The flow skirt is supported at a plurality of circumferentially spaced locations on the lower reactor vessel head that are not equally spaced or vertically aligned with the core barrel attachment points, and the flow skirt employs a unique arrangement of hole patterns that assure a substantially balanced pressure and flow of the coolant over the entire underside of the lower core support plate.

Vessel abnormalization: another hallmark of cancer? Molecular mechanisms and therapeutic implications.

PubMed

De Bock, Katrien; Cauwenberghs, Sandra; Carmeliet, Peter

2011-02-01

As a result of excessive production of angiogenic molecules, tumor vessels become abnormal in structure and function. By impairing oxygen delivery, abnormal vessels fuel a vicious cycle of non-productive angiogenesis, which creates a hostile microenvironment from where tumor cells escape through leaky vessels and which renders tumors less responsive to chemoradiation. While anti-angiogenic strategies focused on inhibiting new vessel growth and destroying pre-existing vessels, clinical studies showed modest anti-tumor effects. For many solid tumors, anti-VEGF treatment offers greater clinical benefit when combined with chemotherapy. This is partly due to a normalization of the tumor vasculature, which improves cytotoxic drug delivery and efficacy and offers unprecedented opportunities for anti-cancer treatment. Here, we overview key novel molecular players that induce vessel normalization. Copyright © 2010 Elsevier Ltd. All rights reserved.

Control of nasal vasculature and airflow resistance in the dog.

PubMed Central

Lung, M A; Phipps, R J; Wang, J C; Widdicombe, J G

1984-01-01

Nasal vascular and airflow resistances have been measured in dogs, simultaneously on both sides separately. Vascular resistance was measured either by constant flow perfusion of the terminal branch of the maxillary artery (which supplies, via the sphenopalatine artery, the nasal septum, most of the turbinates and the nasal sinuses) or by measuring blood flow through this artery, maintained by the dog's own blood pressure. Airflow resistance was assessed by inserting balloon-tipped endotracheal catheters into the back of each nasal cavity via the nasopharynx, and measuring transnasal pressure at constant airflow through each side of the nose simultaneously. Preliminary experiments indicated that there was 5-10% collateral anastomosis between the two sides. Close-arterial injection of drugs showed different patterns of response. Adrenaline, phenylephrine, chlorpheniramine and low doses of prostaglandin F2 alpha increased vascular resistance and lowered airway resistance. Salbutamol, methacholine and histamine lowered vascular resistance and increased airway resistance. Dobutamine decreased airway resistance with a small increase in vascular resistance. Prostaglandins E1, E2 and F2 alpha (high dose) decreased both vascular and airway resistances. Substance P, eledoisin-related peptide and vasoactive intestinal polypeptide lowered vascular resistance with little change in airway resistance. The results are interpreted in terms of possible drug actions on precapillary resistance vessels, sinusoids and venules, and arteriovenous anastomoses. It is concluded that nasal airway resistance cannot be correlated with vascular resistance or blood flow, since the latter has a complex and ill-defined relationship with nasal vascular blood volume. PMID:6204040

Control of nasal vasculature and airflow resistance in the dog.

PubMed

Lung, M A; Phipps, R J; Wang, J C; Widdicombe, J G

1984-04-01

Nasal vascular and airflow resistances have been measured in dogs, simultaneously on both sides separately. Vascular resistance was measured either by constant flow perfusion of the terminal branch of the maxillary artery (which supplies, via the sphenopalatine artery, the nasal septum, most of the turbinates and the nasal sinuses) or by measuring blood flow through this artery, maintained by the dog's own blood pressure. Airflow resistance was assessed by inserting balloon-tipped endotracheal catheters into the back of each nasal cavity via the nasopharynx, and measuring transnasal pressure at constant airflow through each side of the nose simultaneously. Preliminary experiments indicated that there was 5-10% collateral anastomosis between the two sides. Close-arterial injection of drugs showed different patterns of response. Adrenaline, phenylephrine, chlorpheniramine and low doses of prostaglandin F2 alpha increased vascular resistance and lowered airway resistance. Salbutamol, methacholine and histamine lowered vascular resistance and increased airway resistance. Dobutamine decreased airway resistance with a small increase in vascular resistance. Prostaglandins E1, E2 and F2 alpha (high dose) decreased both vascular and airway resistances. Substance P, eledoisin-related peptide and vasoactive intestinal polypeptide lowered vascular resistance with little change in airway resistance. The results are interpreted in terms of possible drug actions on precapillary resistance vessels, sinusoids and venules, and arteriovenous anastomoses. It is concluded that nasal airway resistance cannot be correlated with vascular resistance or blood flow, since the latter has a complex and ill-defined relationship with nasal vascular blood volume.

A study on the structural characteristics and shape of outfitting equipment support in 300K DWT crude oil tanker

NASA Astrophysics Data System (ADS)

Jeong, K.; Jeong, H.; Ji, M.; Kim, J.; Park, J.; Chung, H.

2015-09-01

With the increase in the size and speed of recently built vessels, the output and speed (rpm) of propulsion or generation engines have continuously increased, and the high-output, highspeed engine has become a major cause of excessive vessel noise and vibration. Accordingly, resonance occurs in the equipment and other outfitting equipment installed in a vessel, and thus, periodic requests for correction are received from ship owners or officers. In this study, to resolve this problem, supports that stably fix the outfitting equipment installed in the engine room of a very large crude oil tanker and provide protection from physical or external shock were classified into seven types for three kinds of widely used standard shapes, and an optimized shape was developed and suggested by analyzing the structural characteristics of the shapes of the supports (the maximum bending moment, maximum bending stress, and maximum deformation) using DNV NATICUS HULL 3D BEAM, a structural analysis program, so that it could be used for the outfitting design of a vessel.

Multinozzle Multichannel Temperature Deposition System for Construction of a Blood Vessel.

PubMed

Liu, Huanbao; Zhou, Huixing; Lan, Haiming; Liu, Fu; Wang, Xuhan

2018-02-01

3D bioprinting is an emerging technology that drives us to construct the complicated tissues and organs consisting of various materials and cells, which has been in widespread use in tissue engineering and organ regeneration. However, the protection and accurate distribution of cells are the most urgent problems to achieve tissue and organ reconstruction. In this article, a multinozzle multichannel temperature deposition and manufacturing (MTDM) system is proposed to fabricate a blood vessel with heterogeneous materials and gradient hierarchical porous structures, which enables not only the reconstruction of a blood vessel with an accurate 3D model structure but also the capacity to distribute bioactive materials such as growth factors, nutrient substance, and so on. In addition, a coaxial focusing nozzle is proposed and designed to extrude the biomaterial and encapsulation material, which can protect the cell from damage. In the MTDM system, the tubular structure of a blood vessel was successfully fabricated with the different biomaterials, which proved that the MTDM system has a potential application prospect in tissue engineering and organ regeneration.

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.

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.

Structural Integrity of Water Reactor Pressure Boundary Components.

DTIC Science & Technology

1980-08-01

Boiler and Pressure Vessel Code , Sec. Ill). Estimates of the upper shelf K level from small-specimen...from Appendix A of Section XI of the ASME Boiler and Pressure Vessel Code [11. Figure 9 shows this same data set, together with earlier data for...0969, NRL Memo- randum Report 4063, Sep. 1979. 11. Section XI - ASME Boiler and Pressure Vessel Code , Rules for Inservice Inspection of Nuclear

Secondary Impacts on Structures on the Lunar Surface

NASA Technical Reports Server (NTRS)

Christiansen, Eric; Walker, James D.; Grosch, Donald J.

2010-01-01

The Altair Lunar Lander is being designed for the planned return to the Moon by 2020. Since it is hoped that lander components will be re-used by later missions, studies are underway to examine the exposure threat to the lander sitting on the Lunar surface for extended periods. These threats involve both direct strikes of meteoroids on the vehicle as well as strikes from Lunar regolith and rock thrown by nearby meteorite strikes. Currently, the lander design is comprised of up to 10 different types of pressure vessels. These vessels included the manned habitation module, fuel, cryogenic fuel and gas storage containers, and instrument bays. These pressure vessels have various wall designs, including various aluminum alloys, honeycomb, and carbon-fiber composite materials. For some of the vessels, shielding is being considered. This program involved the test and analysis of six pressure vessel designs, one of which included a Whipple bumper shield. In addition to the pressure vessel walls, all the pressure vessels are wrapped in multi-layer insulation (MLI). Two variants were tested without the MLI to better understand the role of the MLI in the impact performance. The tests of performed were to examine the secondary impacts on these structures as they rested on the Lunar surface. If a hypervelocity meteor were to strike the surface nearby, it would throw regolith and rock debris into the structure at a much lower velocity. Also, when the manned module departs for the return to Earth, its rocket engines throw up debris that can impact the remaining lander components and cause damage. Glass spheres were used as a stimulant for the regolith material. Impact tests were performed with a gas gun to find the V50 of various sized spheres striking the pressure vessels. The impacts were then modeled and a fast-running approximate model for the V50 data was developed. This model was for performing risk analysis to assist in the vessel design and in the identification of ideal long-term mission sites. This paper reviews the impact tests and analysis and modeling examining the impact threat to various components in the lander design.

NOVEL PRERETINAL HAIR PIN-LIKE VESSEL IN RETINAL ASTROCYTIC HAMARTOMA WITH VITREOUS HEMORRHAGE.

PubMed

Soeta, Megumi; Arai, Yusuke; Takahashi, Hidenori; Fujino, Yujiro; Tanabe, Tatsuro; Inoue, Yuji; Kawashima, Hidetoshi

2018-01-01

To report a case of retinal astrocytic hamartoma with vitreous hemorrhage and a hair pin-like vessel adhering to a posterior vitreous membrane. A 33-year-old man with a retinal astrocytic hamartoma presented with vitreous hemorrhage 5 times. Multimodal imaging, including fundus photography, fluorescein angiography, optical coherence tomography, and B-mode ultrasonography. Multimodal imaging demonstrated a novel hair pin-like vessel that adhered to the posterior vitreous membrane. Some cases of retinal astrocytic hamartoma with vitreous hemorrhage may be related to structure abnormalities of tumor vessels.

Reactor vessel support system. [LMFBR

DOEpatents

Golden, M.P.; Holley, J.C.

1980-05-09

A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

RAPID COMMUNICATION: Magnetic resonance imaging inside metallic vessels

NASA Astrophysics Data System (ADS)

Han, Hui; Balcom, Bruce J.

2010-10-01

We introduce magnetic resonance imaging (MRI) measurements inside metallic vessels. Until now, MRI has been unusable inside metallic vessels because of eddy currents in the walls. We have solved the problem and generated high quality images by employing a magnetic field gradient monitoring method. The ability to image within metal enclosures and structures means many new samples and systems are now amenable to MRI. Most importantly this study will form the basis of new MRI-compatible metallic pressure vessels, which will permit MRI of macroscopic systems at high pressure.

Multi-atlas pancreas segmentation: Atlas selection based on vessel structure.

PubMed

Karasawa, Ken'ichi; Oda, Masahiro; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Chu, Chengwen; Zheng, Guoyan; Rueckert, Daniel; Mori, Kensaku

2017-07-01

Automated organ segmentation from medical images is an indispensable component for clinical applications such as computer-aided diagnosis (CAD) and computer-assisted surgery (CAS). We utilize a multi-atlas segmentation scheme, which has recently been used in different approaches in the literature to achieve more accurate and robust segmentation of anatomical structures in computed tomography (CT) volume data. Among abdominal organs, the pancreas has large inter-patient variability in its position, size and shape. Moreover, the CT intensity of the pancreas closely resembles adjacent tissues, rendering its segmentation a challenging task. Due to this, conventional intensity-based atlas selection for pancreas segmentation often fails to select atlases that are similar in pancreas position and shape to those of the unlabeled target volume. In this paper, we propose a new atlas selection strategy based on vessel structure around the pancreatic tissue and demonstrate its application to a multi-atlas pancreas segmentation. Our method utilizes vessel structure around the pancreas to select atlases with high pancreatic resemblance to the unlabeled volume. Also, we investigate two types of applications of the vessel structure information to the atlas selection. Our segmentations were evaluated on 150 abdominal contrast-enhanced CT volumes. The experimental results showed that our approach can segment the pancreas with an average Jaccard index of 66.3% and an average Dice overlap coefficient of 78.5%. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural design and stress analysis program for advanced composite filament-wound axisymmetric pressure vessels (COMTANK)

NASA Technical Reports Server (NTRS)

Knoell, A. C.

1972-01-01

Computer program has been specifically developed to handle, in an efficient and cost effective manner, planar wound pressure vessels fabricated of either boron-epoxy or graphite-epoxy advanced composite materials.

Statins attenuate the development of atherosclerosis and endothelial dysfunction induced by exposure to urban particulate matter (PM{sub 10})

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

Miyata, Ryohei; Hiraiwa, Kunihiko; Cheng, Jui Chih

Exposure to ambient air particulate matter (particles less than 10 μm or PM{sub 10}) has been shown to be an independent risk factor for the development and progression of atherosclerosis. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have well-established anti-inflammatory properties. The aim of this study was to determine the impact of statins on the adverse functional and morphological changes in blood vessels induced by PM{sub 10}. New Zealand White rabbits fed with a high fat diet were subjected to balloon injury to their abdominal aorta followed by PM{sub 10}/saline exposure for 4 weeks ± lovastatin (5 mg/kg/day) treatment. PM{submore » 10} exposure accelerated balloon catheter induced plaque formation and increased intimal macrophages and lipid accumulation while lovastatin attenuated these changes and promoted smooth muscle cell recruitment into plaques. PM{sub 10} impaired vascular acetylcholine (Ach) responses and increased vasoconstriction induced by phenylephrine as assessed by wire myograph. Supplementation of nitric oxide improved the impaired Ach responses. PM{sub 10} increased the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in blood vessels and increased the plasma levels of endothelin-1 (ET-1). Incubation with specific inhibitors for iNOS, COX-2 or ET-1 in the myograph chambers significantly improved the impaired vascular function. Lovastatin decreased the expression of these mediators in atherosclerotic lesions and improved endothelial dysfunction. However, lovastatin was unable to reduce blood lipid levels to the baseline level in rabbits exposed to PM{sub 10}. Taken together, statins protect against PM{sub 10}-induced cardiovascular disease by reducing atherosclerosis and improving endothelial function via their anti-inflammatory properties. - Highlights: • Coarse particulate matter (PM{sub 10}) accelerated balloon injury-induced plaque formation. • Lovastatin decreased intimal macrophages, lipid accumulation, and intimal area. • Lovastatin promoted smooth muscle cell recruitment into plaques. • Lovastatin reduced the expression of vasoactive mediators (iNOS, COX-2, and ET-1). • Lovastatin did not reduce blood lipid levels in PM{sub 10}-exposed rabbits.« less

Hanging core support system for a nuclear reactor. [LMFBR

DOEpatents

Burelbach, J.P.; Kann, W.J.; Pan, Y.C.; Saiveau, J.G.; Seidensticker, R.W.

1984-04-26

For holding the reactor core in the confining reactor vessel, a support is disclosed that is structurally independent of the vessel, that is dimensionally accurate and stable, and that comprises tandem tension linkages that act redundantly of one another to maintain stabilized core support even in the unlikely event of the complete failure of one of the linkages. The core support has a mounting platform for the reactor core, and unitary structure including a flange overlying the top edge of the reactor vessels, and a skirt and box beams between the flange and platform for establishing one of the linkages. A plurality of tension rods connect between the deck closing the reactor vessel and the platform for establishing the redundant linkage. Loaded Belleville springs flexibly hold the tension rods at the deck and separable bayonet-type connections hold the tension rods at the platform.

Industrializing Offshore Wind Power with Serial Assembly and Lower-cost Deployment - Final Report

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

Kempton, Willett

A team of engineers and contractors has developed a method to move offshore wind installation toward lower cost, faster deployment, and lower environmental impact. A combination of methods, some incremental and some breaks from past practice, interact to yield multiple improvements. Three designs were evaluated based on detailed engineering: 1) a 5 MW turbine on a jacket with pin piles (base case), 2) a 10 MW turbine on a conventional jacket with pin piles, assembled at sea, and 3) a 10 MW turbine on tripod jacket with suction buckets (caissons) and with complete turbine assembly on-shore. The larger turbine, assemblymore » ashore, and the use of suction buckets together substantially reduce capital cost of offshore wind projects. Notable capital cost reductions are: changing from 5 MW to 10 MW turbine, a 31% capital cost reduction, and assembly on land then single-piece install at sea an additional 9% capital cost reduction. An estimated Design 4) estimates further cost reduction when equipment and processes of Design 3) are optimized, rather than adapted to existing equipment and process. Cost of energy for each of the four Designs are also calculated, yielding approximately the same percentage reductions. The methods of Design 3) analyzed here include accepted structures such as suction buckets used in new ways, innovations conceived but previously without engineering and economic validation, combined with new methods not previously proposed. Analysis of Designs 2) and 3) are based on extensive engineering calculations and detailed cost estimates. All design methods can be done with existing equipment, including lift equipment, ports and ships (except that design 4 assumes a more optimized ship). The design team consists of experienced offshore structure designers, heavy lift engineers, wind turbine designers, vessel operators, and marine construction contractors. Comparing the methods based on criteria of cost and deployment speed, the study selected the third design. That design is, in brief: a conventional turbine and tubular tower is mounted on a tripod jacket, in turn atop three suction buckets. Blades are mounted on the tower, not on the hub. The entire structure is built in port, from the bottom up, then assembled structures are queued in the port for deployment. During weather windows, the fully-assembled structures are lifted off the quay, lashed to the vessel, and transported to the deployment site. The vessel analyzed is a shear leg crane vessel with dynamic positioning like the existing Gulliver, or it could be a US-built crane barge. On site, the entire structure is lowered to the bottom by the crane vessel, then pumping of the suction buckets is managed by smaller service vessels. Blades are lifted into place by small winches operated by workers in the nacelle without lift vessel support. Advantages of the selected design include: cost and time at sea of the expensive lift vessel are significantly reduced; no jack up vessel is required; the weather window required for each installation is shorter; turbine structure construction is continuous with a queue feeding the weather-dependent installation process; pre-installation geotechnical work is faster and less expensive; there are no sound impacts on marine mammals, thus minimal spotting and no work stoppage Industrializing Offshore Wind Power 6 of 96 9 for mammal passage; the entire structure can be removed for decommissioning or major repairs; the method has been validated for current turbines up to 10 MW, and a calculation using simple scaling shows it usable up to 20 MW turbines.« less

Waste management for different fusion reactor designs

NASA Astrophysics Data System (ADS)

Rocco, Paolo; Zucchetti, Massimo

2000-12-01

Safety and Environmental Assessment of Fusion Power (SEAFP) waste management studies performed up to 1998 concerned three power tokamak designs. In-vessel structural materials consist of V-alloys or low activation martensitic (LAM) steel; tritium-producing materials are Li 2O, Pb-17Li, Li 4SiO 4 with a Be-multiplier; coolants are helium or water. The strategy chosen reduces permanent radwaste by recycling the in-vessel materials and by clearance of the other structures. Limits of the contact dose rate and specific activity of the waste allowing such options are defined accordingly. SEAFP activities for 1999 enlarge the analysis to three additional reactors with in-vessel structures made with SiC/SiC composites. These materials cannot be recycled due to their form and, according to national regulations of E.C. countries, long-lived activation products hinder near-surface burial (NSB).

Characterisation of Feature Points in Eye Fundus Images

NASA Astrophysics Data System (ADS)

Calvo, D.; Ortega, M.; Penedo, M. G.; Rouco, J.

The retinal vessel tree adds decisive knowledge in the diagnosis of numerous opthalmologic pathologies such as hypertension or diabetes. One of the problems in the analysis of the retinal vessel tree is the lack of information in terms of vessels depth as the image acquisition usually leads to a 2D image. This situation provokes a scenario where two different vessels coinciding in a point could be interpreted as a vessel forking into a bifurcation. That is why, for traking and labelling the retinal vascular tree, bifurcations and crossovers of vessels are considered feature points. In this work a novel method for these retinal vessel tree feature points detection and classification is introduced. The method applies image techniques such as filters or thinning to obtain the adequate structure to detect the points and sets a classification of these points studying its environment. The methodology is tested using a standard database and the results show high classification capabilities.

A novel fibrous duct structure discovered in the brain meninges by using polarized light microscopy

NASA Astrophysics Data System (ADS)

Nam, Min-Ho; Jung, Sharon Jiyoon; Soh, Kwang-Sup; Lim, Jaekwan; Seo, Eunseok; Lim, Jun; Baek, Miok; Lee, Sang Joon

2016-05-01

We have previously reported the discovery of a novel fibrous structure (NFS) consisting of unidirectionally arranged collagen fibers in the spinal pia mater. Due to its unique structure, it was easily detected using polarized light microscopy. In the current study, we describe the discovery of a similar NFS in the brain meninges of rats by using polarized light microscopy. This NFS is located beneath the superior sagittal sinus. Initially, we systemically analyzed the polarization properties of the NFS. The change in the light intensity of the NFS, with respect to the polarization angle, was eight times greater than that of blood vessels, showing that the collagen fibers are oriented in a particular direction with almost perfect parallelism (0.99). The orientation angle of the polarization ellipse confirmed the orientation of the collagen fibers in the NFS. Histological studies further confirmed that the unidirectionally arranged collagen fibers were responsible for this distinct polarization property. Surprisingly, X-ray microtomography and 3D confocal imaging revealed that the NFS contains within it a duct structure, a putative primo vessel. In conclusion, we report a NFS in the brain meninges, detected by using polarized light microscopy, that provides space for a putative primo vessel, not a blood vessel.

Stability, structure and scale: improvements in multi-modal vessel extraction for SEEG trajectory planning.

PubMed

Zuluaga, Maria A; Rodionov, Roman; Nowell, Mark; Achhala, Sufyan; Zombori, Gergely; Mendelson, Alex F; Cardoso, M Jorge; Miserocchi, Anna; McEvoy, Andrew W; Duncan, John S; Ourselin, Sébastien

2015-08-01

Brain vessels are among the most critical landmarks that need to be assessed for mitigating surgical risks in stereo-electroencephalography (SEEG) implantation. Intracranial haemorrhage is the most common complication associated with implantation, carrying significantly associated morbidity. SEEG planning is done pre-operatively to identify avascular trajectories for the electrodes. In current practice, neurosurgeons have no assistance in the planning of electrode trajectories. There is great interest in developing computer-assisted planning systems that can optimise the safety profile of electrode trajectories, maximising the distance to critical structures. This paper presents a method that integrates the concepts of scale, neighbourhood structure and feature stability with the aim of improving robustness and accuracy of vessel extraction within a SEEG planning system. The developed method accounts for scale and vicinity of a voxel by formulating the problem within a multi-scale tensor voting framework. Feature stability is achieved through a similarity measure that evaluates the multi-modal consistency in vesselness responses. The proposed measurement allows the combination of multiple images modalities into a single image that is used within the planning system to visualise critical vessels. Twelve paired data sets from two image modalities available within the planning system were used for evaluation. The mean Dice similarity coefficient was 0.89 ± 0.04, representing a statistically significantly improvement when compared to a semi-automated single human rater, single-modality segmentation protocol used in clinical practice (0.80 ± 0.03). Multi-modal vessel extraction is superior to semi-automated single-modality segmentation, indicating the possibility of safer SEEG planning, with reduced patient morbidity.

Equation of state of an ideal gas with nonergodic behavior in two connected vessels.

PubMed

Naplekov, D M; Semynozhenko, V P; Yanovsky, V V

2014-01-01

We consider a two-dimensional collisionless ideal gas in the two vessels connected through a small hole. One of them is a well-behaved chaotic billiard, another one is known to be nonergodic. A significant part of the second vessel's phase space is occupied by an island of stability. In the works of Zaslavsky and coauthors, distribution of Poincaré recurrence times in similar systems was considered. We study the gas pressure in the vessels; it is uniform in the first vessel and not uniform in second one. An equation of the gas state in the first vessel is obtained. Despite the very different phase-space structure, behavior of the second vessel is found to be very close to the behavior of a good ergodic billiard but of different volume. The equation of state differs from the ordinary equation of ideal gas state by an amendment to the vessel's volume. Correlation of this amendment with a share of the phase space under remaining intact islands of stability is shown.

Effect of prolonged hypokinesia on resistance of resistive vessels in rats

NASA Technical Reports Server (NTRS)

Saltykova, V. A.

1982-01-01

Under the effect of prolonged hypokinesia, the perfusion pressure in resistive vessels, measured under conditions of deep anesthesia and complete denervation, increased by approximately the same degree as arterial pressure in non-anesthetized animals. The increase in arterial, perfusion pressure and the resistance of resistive vessels in animals subjected to prolonged hypokinesia was accompanied by an increase in adrenoreactivity. During prolonged hypokinesia, partial obliteration of the vascular bed of the skeletal muscles plays a significant role in the observed increase in resistance of vessels of the extremities. The increase in adrenoreactivity of the vessels during hypokinesia may be realized as a partial case of an increase in the adrenoreactivity of structures whose innervation is disturbed.

Unmanned surface vessel (USV) systems for bridge inspection : [summary].

DOT National Transportation Integrated Search

2016-08-01

Florida Atlantic University researchers studied the : use of unmanned surface vessels (USVs) for bridge : inspection. The general concept is that a bridge : inspection team would use an USV to perform an : initial survey of structures underwater and ...

Chemical Fracturing of Refractory-Metal Vessels

NASA Technical Reports Server (NTRS)

Campana, R. J.

1986-01-01

Localized reactions cause refractory-metal vessels to break up at predetermined temperatures. Device following concept designed to break up along predetermined lines into smaller pieces at temperature significantly below melting point of metal from which made. Possible applications include fire extinguishers that breakup to release extinguishing gas in enclosed areas, pressure vessels that could otherwise burst dangerously in fire, and self-destroying devices. Technique particularly suitable modification to already existing structures.

Experimental comparison of landmark-based methods for 3D elastic registration of pre- and postoperative liver CT data

NASA Astrophysics Data System (ADS)

Lange, Thomas; Wörz, Stefan; Rohr, Karl; Schlag, Peter M.

2009-02-01

The qualitative and quantitative comparison of pre- and postoperative image data is an important possibility to validate surgical procedures, in particular, if computer assisted planning and/or navigation is performed. Due to deformations after surgery, partially caused by the removal of tissue, a non-rigid registration scheme is a prerequisite for a precise comparison. Interactive landmark-based schemes are a suitable approach, if high accuracy and reliability is difficult to achieve by automatic registration approaches. Incorporation of a priori knowledge about the anatomical structures to be registered may help to reduce interaction time and improve accuracy. Concerning pre- and postoperative CT data of oncological liver resections the intrahepatic vessels are suitable anatomical structures. In addition to using branching landmarks for registration, we here introduce quasi landmarks at vessel segments with high localization precision perpendicular to the vessels and low precision along the vessels. A comparison of interpolating thin-plate splines (TPS), interpolating Gaussian elastic body splines (GEBS) and approximating GEBS on landmarks at vessel branchings as well as approximating GEBS on the introduced vessel segment landmarks is performed. It turns out that the segment landmarks provide registration accuracies as good as branching landmarks and can improve accuracy if combined with branching landmarks. For a low number of landmarks segment landmarks are even superior.

Equine palmar artery, palmar vein and uterine artery express different populations of vasoactive biogenic amine receptors

USDA-ARS?s Scientific Manuscript database

Consumption of endophyte-infected (Neotyphodium coenophialum) tall fescue (Lolium arundinaceum) seed by horses causes constriction of the palmar artery (PA), palmar vein (PV) and reduced blood flow to the corpus luteum that can be measured in vivo by Doppler ultrasonography. In addition, myograph st...

Constriction of bovine vasculature by endophyte-infected tall fescue seed extract is similar to pure ergovaline

USDA-ARS?s Scientific Manuscript database

Ergovaline has been extensively used to study vasoactive effects of endophyte- (Neotyphodium coenophialum) infected tall fescue (Lolium arundinaceum). However, preliminary in vitro tests indicated that an extract of toxic tall fescue seed (E+EXT) is more potent than ergovaline alone in a right rumin...

Exploring ischemia-induced vascular lesions and potential pharmacological intervention strategies.

PubMed

Aliev, G; Obrenovich, M E; Seyidova, D; de la Torre, J C

2005-01-01

Structural changes in vessels under the influence of ischemia play an important role in the pathogenesis of many diseases, most important of which are stroke and myocardial infarction or myocardial insult. Over the years, information has been gathered, which implicate a role for ischemic vascular changes in the pathogenesis of crush-syndrome, atherosclerosis and other vascular diseases. When blood vessels are damaged they become unresponsive to a stimulus, which normally elicits vasodilatation and can lead to intraluminal thrombosis and ischemic events. The aim of this review is to explore the structural changes seen in vessels affected by ischemia reperfusion injury. With ischemia, the development of observable changes to vascular structure is multifactorial. One key factor is reperfusion ischemic injury. Moreover, the duration of the ischemic event is an important factor when determining both the prognosis and the type of morphological change that is observable in affected vessel walls. In this regard, the deleterious progression of blood flow impairment and its severity depends on the specific organ involved and the type of tissue affected. Further, there are regional differences within affected tissues and the degree of microvascular injury is well correlated with differences in the nature and severity of the ischemic event. Any method aimed at preventing and treating ischemic reperfusion injuries in vessels, based on these investigations, should likewise be able to decrease the early signs of brain, cerebrovascular and heart injury and preserve normal cellular architecture.

Glioblastoma niches: from the concept to the phenotypical reality.

PubMed

Schiffer, Davide; Mellai, Marta; Bovio, Enrica; Bisogno, Ilaria; Casalone, Cristina; Annovazzi, Laura

2018-05-08

Recently, the concept of niches as sites of tumor progression, invasion, and angiogenesis in glioblastoma (GB) has been extensively debated. Niches, considered the sites in which glioblastoma stem cells (GSCs) reside, have been classified as perivascular, perinecrotic, and invasive. However, from a neuropathological point of view, it is not easy to establish when a tumor structure can be considered a niche. The relevant literature has been reviewed in the light of our recent experience on the subject. As for perinecrotic niches, the occurrence of GSCs around necrosis is interpreted as triggered by hypoxia through HIF-1α. Our alternative hypothesis is that, together with progenitors, they are the cell constituents of hyper-proliferative areas of GB, where perinecrotic niches have developed, and they would, therefore, represent the remnants of GSCs/progenitors spared by the developing necrosis. Perivascular structures originate from both transport vessels and exchange vessels, i.e., venules, arterioles, or the undefinable neo-formed small vessels, but only those in which a direct contact between GSCs/progenitors and endothelial cells occurs can be called niches. Both pericytes and microglia/macrophages play a role in niche function: Macrophages of blood origin invade GB only after the appearance of "mother vessels" with consequent blood-brain barrier disruption. Not all vessel/tumor cell structures can be considered niches, that is, crucial sites of tumor progression, invasion, and angiogenesis.

Vasoactive intestinal polypeptide provokes acetylcholine release from the myenteric plexus

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

Kusunoki, M.; Tsai, L.H.; Taniyama, K.

1986-07-01

Effects of vasoactive intestinal polypeptide (VIP) on the release of acetylcholine (ACh) from longitudinal muscle strips with myenteric plexus (LM) preparations were examined in the guinea pig small intestine. VIP (10 to 10 W M) induced a concentration-dependent contraction of LM preparation. The VIP-induced contractions seem to be related to three components, the scopolamine-sensitive, the scopolamine-insensitive, the tetrodotoxin-sensitive, and the tetrodotoxin-insensitive contractions. VIP (10 to 10 W M) induced a concentration-dependent increase in the release of (TH)ACh from LM preparations preloaded with (TH)choline. The VIP-evoked (TH)ACh release was inhibited by removal of CaS from the perfusion medium and by treatmentmore » with tetrodotoxin but not by scopolamine and hexamethonium. The spontaneous and VIP-evoked (TH)ACh release was not affected by phentolamine, propranolol, methysergide, diphenhydramine, cimetidine, bicuculline, or (D-ProS, D-Trp/sup 7,9/)substance P. The result demonstrates that VIP induces contractions of longitudinal smooth muscle directly and indirectly by the stimulation of both cholinergic neurons and noncholinergic excitatory neurons.« less

Effects of vasoactive intestinal peptide on vascular conductance are unaffected by anesthesia

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

Bouder, T.G.; Huffman, L.J.; Hedge, G.A.

1988-12-01

In rats anesthetized with ketamine and pentobarbital (KET/PB), vasoactive intestinal peptide (VIP) increases vascular conductance (VC) in the salivary gland, pancreas, and thyroid gland, whereas no changes in VC are observed in a number of other organs. Because anesthesia may alter the responsiveness of physiological systems, we compared the effects of VIP on organ VC in conscious or anesthetized rats. Chronically catheterized rats were studied in the conscious state or 30 min after induction of anesthesia with KET/PB, isoflurane, or Inactin. Blood flows were measured by the reference sample version of the radioactive microsphere (MS) technique using two MS injectionsmore » ({sup 141}Ce-MS/{sup 85}Sr-MS). Mean arterial blood pressure was monitored and used in the calculation of VC. Organ VCs were similar under basal conditions in conscious and anesthetized rats. VIP infusion caused systemic hypotension and increased VCs in the salivary gland, pancreas, and thyroid gland, and these responses were largely unaffected by anesthesia. These results indicate that the anesthetics used do not alter basal VC or the responsiveness of the vasculature to exogenous VIP.« less

Role of pulmonary diseases and physical condition in the regulation of vasoactive hormones.

PubMed

Hietanen, E; Marniemi, J; Liippo, K; Seppänen, A; Hartiala, J; Viinamäki, O

1988-12-01

Lungs have many non-respiratory metabolic functions, of which some take place in the capillary endothelium, while others are in parenchymal lung tissue. We have studied the role of the lungs in the metabolism of vasoactive and some other hormones by comparing patients who have undergone lung resection to those having various obstructive or fibrotic lung diseases. We have also compared these groups with persons in good physical health. The data suggested that lung resection patients had low angiotensin II levels in plasma but the response of angiotensin II to exercise was normal. Also adrenalin concentration was low in the lung resection group while dopamine did not show any significant difference between the groups. When hormone levels were correlated to the exercise data, renin levels were especially related to physical condition. Serum post-exercise renin values were inversely related to the uneven distribution of lung perfusion, possibly thus reflecting the diminished pulmonary vascularization. A negative association was found between angiotensin II and diffusion capacity. Thus, the angiotensin II levels may preferably be controlled by the non-circulatory functions of the lungs.

The vasorelaxant mechanisms of methanol on isolated rat aortic rings: Involvement of ion channels and signal transduction pathways.

PubMed

Bai, Y; Zhang, Q; Yang, Z; Meng, Z; Zhao, Q

2017-10-01

It is reported that methanol is generally used as an industrial solvent, antifreeze, windshield washer fluid, cooking fuel and perfume. Methanol ingestion can lead to severe metabolic disturbances, blindness, or even death. So far, few studies about its negative effects on cardiovascular system have been reported. The purpose of this study was to determine the vasoactive effect of methanol and roles of ion channels and signal transduction pathways on isolated rat aorta. The results suggested that the mechanism of methanol-induced vasorelaxation at low concentrations (<500 mM) was mediated by ATP-sensitive K + (K ATP ) and L-type Ca 2+ channels, but the mechanism at high concentrations (>600 mM) was related to K ATP , voltage-dependent K + , big-conductance Ca 2+ -activated K + , L-type Ca 2+ channels as well as prostacyclin, protein kinase C, β-adrenoceptors pathways. In addition, methanol induced a dose-dependent inhibition of vasoconstrictions caused by calcium chloride, potassium chloride, or norepinephrine. Further work is needed to investigate the relative contribution of each channel and pathway in methanol-induced vasoactive effect.

Active immunization against vasoactive intestinal polypeptide decreases neuronal recruitment and inhibits reproduction in zebra finches.

PubMed

Vistoropsky, Yulia; Heiblum, Rachel; Smorodinsky, Nechama-Ina; Barnea, Anat

2016-08-15

Neurogenesis and neuronal recruitment occur in adult brains of many vertebrates, and the hypothesis is that these phenomena contribute to the brain plasticity that enables organisms to adjust to environmental changes. In mammals, vasoactive intestinal polypeptide (VIP) is known to have many neuroprotective properties, but in the avian brain, although widely distributed, its role in neuronal recruitment is not yet understood. In the present study we actively immunized adult zebra finches against VIP conjugated to KLH and compared neuronal recruitment in their brains, with brains of control birds, which were immunized against KLH. We looked at two forebrain regions: the nidopallium caudale (NC), which plays a role in vocal communication, and the hippocampus (HC), which is involved in the processing of spatial information. Our data demonstrate that active immunization against VIP reduces neuronal recruitment, inhibits reproduction, and induces molting, with no change in plasma prolactin levels. Thus, our observations suggest that VIP has a direct positive role in neuronal recruitment and reproduction in birds. J. Comp. Neurol. 524:2516-2528, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Cellular and molecular mechanisms regulating vascular tone. Part 1: basic mechanisms controlling cytosolic Ca2+ concentration and the Ca2+-dependent regulation of vascular tone.

PubMed

Akata, Takashi

2007-01-01

General anesthetics cause hemodynamic instability and alter blood flow to various organs. There is mounting evidence that most general anesthetics, at clinical concentrations, influence a wide variety of cellular and molecular mechanisms regulating the contractile state of vascular smooth muscle cells (i.e., vascular tone). In addition, in current anesthetic practice, various types of vasoactive agents are often used to control vascular reactivity and to sustain tissue blood flow in high-risk surgical patients with impaired vital organ function and/or hemodynamic instability. Understanding the physiological mechanisms involved in the regulation of vascular tone thus would be beneficial for anesthesiologists. This review, in two parts, provides an overview of current knowledge about the cellular and molecular mechanisms regulating vascular tone-i.e., targets for general anesthetics, as well as for vasoactive drugs that are used in intraoperative circulatory management. This first part of the two-part review focuses on basic mechanisms regulating cytosolic Ca2+ concentration and the Ca2+-dependent regulation of vascular tone.

Survey of long-term durability of fiberglass reinforced plastic structures

NASA Technical Reports Server (NTRS)

Lieblein, S.

1981-01-01

Included are fluid containment vessels, marine structures, and aircraft components with up to 19 years of service. Correlations were obtained for the variation of static fatigue strength, cyclic fatigue strength, and residual burst strength for pressure vessels. In addition, data are presented for the effects of moisture on strength retention. Data variations were analyzed, and relationships and implications for testing are discussed. Change in strength properties for complete structures was examined for indications of the effects of environmental conditions such as moisture and outdoor exposure (ultraviolet radiation, weathering) on long term durability.

[Possible effect of E-selectine on structure and function of arterial vessels in patients with metabolic syndrome].

PubMed

Voloshyna, O O; Lyzohub, V H; Romanenko, I M

2007-01-01

Endothelial dysfunction and endothelial cells activation as it was shown in patients with ischemic heart disease play important role in atherosclerosis progression and the development of cardiovascular events. Relationship between E-selectine and functional/ structural changes of the arterial vessels in patients with metabolic syndrome was not explored. We revealed that both activation of the endothelial cells and structural/functional changes of the arterial wall mostly depend on obesity and dislipedemia and in less extent on carbohydrates metabolism disorders.

[The mechanism of vasculogenesis: the critical role of transforming growth factor-beta 1 in the formation of vessel-like structures during the differentiation in vitro of murine embryonic stem cells].

PubMed

Tsung, H C; Yao, Z

1996-09-01

When ES-5 cells were transfected with an exogenous porcine TGF-beta 1 gene, one can obtain clones of genetically modified ES cells with over-expression of the transfected gene. We called the genetically modified ES-5 cells as ES-T cells. When ES-T cells were used to study their differentiation in vitro by all trans-retinoic acid (RA), it was soon noticed that embryoid bodies of ES-T cells can exclusively differentiate into endothelial cells and vessel-like structures, but not in their parent ES-5 cells. The above result is the first indication that the differentiation of tubular structures in embryoid bodies of ES-T cells may somehow be related to TGF-beta 1. To demonstrate further the role of TGF-beta 1 in the formation of vessel-like structures, the cultured ES-5 cells in the presence of added rhTGF-beta 1 were closely followed in the course of their differentiation. We have, thus, demonstrated the promoting effects of exogenous rhTGF-beta 1 in the formation of vessel-like structures, morphologically similar to those structures derived from ES-T6 cells, during the differentiation of ES-5 cells, both in monolayer culture, in three dimensional collagen gel and in embryoid bodies cultured on gelatin-coated tissue culture wells. Addition of suitable amount of anti-TGF-beta 1 monoclonal antibody IgG (TB21) to the culture medium of embryoid bodies of ES-T6 cells could effectively abolish the formation of vessel-like structures induced by retinoic acid. The percentage of the inhibition was very high, giving a figure comparable to that of atypical vessel-like structures formed in the control embryoid bodies from their parent ES-5 cells. The flat epithelial-like cells and round cells differentiated from embryoid bodies of ES-T6 cells were stained rather strongly for laminin and type IV collagen by immunofluorescent procedure. The above results indicate clearly that TGF-beta 1 is a crucial factor in organizing the differentiated derivatives (endothelial-like cells and their immediate progenitor cells) from ES-T6 cells to form vessel-like structures, and that the role of TGF-beta 1 in vasculogenesis might be performed, in part, through the modulation of the composition and organization of the extracellular matrix. In addition, the enhanced expression of bFGF mRNA in derivatives differentiated from both ES-5 cells treated with rhTGF-beta 1 and ES-T6 cells were detected by Northern blot analysis. Thus, aside from its effects on extracellular matrix, TGF-beta 1 might also modulate the bioactivity of bFGF in relation to the growth of vascular endothelial cells in the present system.

Effective isolation of primo vessels in lymph using sound- and ultrasonic-wave stimulation.

PubMed

Park, Do-Young; Lee, Hye-Rie; Rho, Min-Suk; Lee, Sang-Suk

2014-12-01

The effects of stimulation with sound and ultrasonic waves of a specific bandwidth on the microdissection of primo vessels in lymphatic vessels of rabbit were investigated. The primo vessels stained with alcian-blue dye injected in the lymph nodes were definitely visualized and more easily isolated by sound-wave vibration and ultrasonic stimulation applied to rabbits at various frequencies and intensities. With sound wave at 7 Hz and ultrasonic waves at 2 MHz, the probability of detecting the primo vessels was improved to 90%; however, without wave stimulation the probability of discovering primo vessels was about 50% only. Sound and ultrasonic waves at specific frequency bands should be effective for microdissection of the primo vessels in the abdominal lymph of rabbit. We suggest that oscillation of the primo vessels by sound and ultrasonic waves may be useful to visualize specific primo structure, and wave vibration can be a very supportive process for observation and isolation of the primo vessels of rabbits. Copyright © 2014. Published by Elsevier B.V.

Label-free optical lymphangiography: development of an automatic segmentation method applied to optical coherence tomography to visualize lymphatic vessels using Hessian filters

PubMed Central

Yousefi, Siavash; Qin, Jia; Zhi, Zhongwei

2013-01-01

Abstract. Lymphatic vessels are a part of the circulatory system that collect plasma and other substances that have leaked from the capillaries into interstitial fluid (lymph) and transport lymph back to the circulatory system. Since lymph is transparent, lymphatic vessels appear as dark hallow vessel-like regions in optical coherence tomography (OCT) cross sectional images. We propose an automatic method to segment lymphatic vessel lumen from OCT structural cross sections using eigenvalues of Hessian filters. Compared to the existing method based on intensity threshold, Hessian filters are more selective on vessel shape and less sensitive to intensity variations and noise. Using this segmentation technique along with optical micro-angiography allows label-free noninvasive simultaneous visualization of blood and lymphatic vessels in vivo. Lymphatic vessels play an important role in cancer, immune system response, inflammatory disease, wound healing and tissue regeneration. Development of imaging techniques and visualization tools for lymphatic vessels is valuable in understanding the mechanisms and studying therapeutic methods in related disease and tissue response. PMID:23922124

Evolution in the understanding of the pathophysiological basis of portal hypertension: How changes in paradigm are leading to successful new treatments

PubMed Central

Bosch, Jaume; Groszmann, Roberto J.; Shah, Vijay H.

2015-01-01

Summary Among the common complication of cirrhosis portal hypertension witnessed a major improvement of prognosis during the past decades. Principally due to the introduction of rational treatments based on new pathophysiological paradigms (concepts of thought) developed in the 1980s. The best example being the use of non-selective beta-blockers and of vasopressin analogs, somatostatin, and its analogs. Further refinement in the knowledge of the molecular mechanisms involved in the regulation of both the splanchnic and hepatic circulation has led to the emergence of new treatments, which are based on evidence that show not only structural but also vasoactive components increase the hepatic vascular resistance, as well as of angiogenesis. This knowledge and future improvements will most likely result in more effective treatment of portal hypertension and effective prevention of its complications in early stages. PMID:25920081

Automatic retinal blood vessel parameter calculation in spectral domain optical coherence tomography

NASA Astrophysics Data System (ADS)

Wehbe, Hassan; Ruggeri, Marco; Jiao, Shuliang; Gregori, Giovanni; Puliafito, Carmen A.

2007-02-01

Measurement of retinal blood vessel parameters like the blood blow in the vessels may have significant impact on the study and diagnosis of glaucoma, a leading blinding disease worldwide. Optical coherence tomography (OCT) is a noninvasive imaging technique that can provide not only microscopic structural imaging of the retina but also functional information like the blood flow velocity in the retina. The aim of this study is to automatically extract the parameters of retinal blood vessels like the 3D orientation, the vessel diameters, as well as the corresponding absolute blood flow velocity in the vessel. The parameters were extracted from circular OCT scans around the optic disc. By removing the surface reflection through simple segmentation of the circular OCT scans a blood vessel shadowgram can be generated. The lateral coordinates and the diameter of each blood vessel are extracted from the shadowgram through a series of signal processing. Upon determination of the lateral position and the vessel diameter, the coordinate in the depth direction of each blood vessel is calculated in combination with the Doppler information for the vessel. The extraction of the vessel coordinates and diameter makes it possible to calculate the orientation of the vessel in reference to the direction of the incident sample light, which in turn can be used to calculate the absolute blood flow velocity and the flow rate.

Effect of engineered nanoparticles on vasomotor responses in rat intrapulmonary artery

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

Courtois, Arnaud, E-mail: arnaud.courtois@u-bordeaux2.f; Inserm, U885, Bordeaux, F-33076; Andujar, Pascal

2010-06-01

Pulmonary circulation could be one of the primary vascular targets of finest particles that can deeply penetrate into the lungs after inhalation. We investigated the effects of engineered nanoparticles on vasomotor responses of small intrapulmonary arteries using isometric tension measurements. Acute in vitro exposure to carbon nanoparticles (CNP) decreased, and in some case abolished, the vasomotor responses induced by several vasoactive agents, whereas acute exposure to titanium dioxide nanoparticles (TiO{sub 2}NP) did not. This could be attributed to a decrease in the activity of those vasoactive agents (including PGF{sub 2{alpha}}, serotonin, endothelin-1 and acetylcholine), as suggested when they were exposedmore » to CNP before being applied to arteries. Also, CNP decreased the contraction induced by 30 mM KCl, without decreasing its activity. After endoplasmic reticulum calcium stores depletion (by caffeine and thapsigargin), CaCl{sub 2} addition induced a contraction, dependent on Store-Operated Calcium Channels that was not modified by acute CNP exposure. Further addition of 30 mM KCl elicited a contraction, originating from activation of Voltage-Operated Calcium Channels that was diminished by CNP. Contractile responses to PGF{sub 2{alpha}} or KCl, and relaxation to acetylcholine were modified neither in pulmonary arteries exposed in vitro for prolonged time to CNP or TiO{sub 2}NP, nor in those removed from rats intratracheally instilled with CNP or TiO{sub 2}NP. In conclusion, prolonged in vitro or in vivo exposure to CNP or TiO{sub 2}NP does not affect vasomotor responses of pulmonary arteries. However, acute exposure to CNP decreases contraction mediated by activation of Voltage-Operated, but not Store-Operated, Calcium Channels. Moreover, interaction of some vasoactive agents with CNP decreases their biological activity that might lead to misinterpretation of experimental data.« less

Amelioration of Cardiac Function and Activation of Anti-Inflammatory Vasoactive Peptides Expression in the Rat Myocardium by Low Level Laser Therapy

PubMed Central

Manchini, Martha Trindade; Serra, Andrey Jorge; Feliciano, Regiane dos Santos; Santana, Eduardo Tadeu; Antônio, Ednei Luis; de Tarso Camillo de Carvalho, Paulo; Montemor, Jairo; Crajoinas, Renato Oliveira; Girardi, Adriana Castello Costa; Tucci, Paulo José Ferreira; Silva, José Antônio

2014-01-01

Low-level laser therapy (LLLT) has been used as an anti-inflammatory treatment in several disease conditions, even when inflammation is a secondary consequence, such as in myocardial infarction (MI). However, the mechanism by which LLLT is able to protect the remaining myocardium remains unclear. The present study tested the hypothesis that LLLT reduces inflammation after acute MI in female rats and ameliorates cardiac function. The potential participation of the Renin-Angiotensin System (RAS) and Kallikrein-Kinin System (KKS) vasoactive peptides was also evaluated. LLLT treatment effectively reduced MI size, attenuated the systolic dysfunction after MI, and decreased the myocardial mRNA expression of interleukin-1 beta and interleukin-6 in comparison to the non-irradiated rat tissue. In addition, LLLT treatment increased protein and mRNA levels of the Mas receptor, the mRNA expression of kinin B2 receptors and the circulating levels of plasma kallikrein compared to non-treated post-MI rats. On the other hand, the kinin B1 receptor mRNA expression decreased after LLLT. No significant changes were found in the expression of vascular endothelial growth factor (VEGF) in the myocardial remote area between laser-irradiated and non-irradiated post-MI rats. Capillaries density also remained similar between these two experimental groups. The mRNA expression of the inducible nitric oxide synthase (iNOS) was increased three days after MI, however, this effect was blunted by LLLT. Moreover, endothelial NOS mRNA content increased after LLLT. Plasma nitric oxide metabolites (NOx) concentration was increased three days after MI in non-treated rats and increased even further by LLLT treatment. Our data suggest that LLLT diminishes the acute inflammation in the myocardium, reduces infarct size and attenuates left ventricle dysfunction post-MI and increases vasoactive peptides expression and nitric oxide (NO) generation. PMID:24991808

Influence of aerobic fitness on vasoreactivity in young men.

PubMed

Bell, Preston L; Kelley, Edward T; McCoy, Stephanie M; Credeur, Daniel P

2017-10-01

Previous work has demonstrated a direct relationship between aerobic fitness and vasodilatory function (i.e., flow-mediated dilation; FMD); however, the relation between aerobic fitness and vasoconstrictor responsiveness (i.e., low flow-mediated constriction; L-FMC), and the overall vasoactive range (FMD + L-FMC) is unclear. To test the hypothesis that L-FMC and the overall vasoactive range (FMD + L-FMC) will be related to aerobic fitness in young, healthy men. Twenty men (age: 23 ± 5 years) were recruited, and divided evenly into a higher (HF) vs. lower (LF) aerobic fitness group, quantified via YMCA cycle ergometry (VO 2 peak extrapolation), and a 3-min step test (1-min heart rate recovery). Duplex Doppler-ultrasound was used to assess brachial artery FMD and L-FMC. Estimated VO 2 peak (HF = 55 ± 10 vs. LF = 38 ± 5 mL/kg/min) and heart rate recovery (HF = 36 ± 10 vs. LF = 25 ± 8 beats) were greater in the HF group (P < 0.05). FMD and the vasoactive range were similar between groups; however, L-FMC was significantly greater in HF (HF = -2.5 ± 1.6 vs. LF = -0.7 ± 1.8%, P < 0.05; d = 1.18). A correlational analysis revealed an inverse relationship between L-FMC and both HR recovery (r = -0.665, P < 0.01) and estimated VO 2 peak (r = -0.5, P < 0.05). This work supports an association between L-FMC and aerobic fitness in young, healthy men. Longitudinal or interventional studies are warranted to support causality, and to distinguish whether L-FMC is more sensitive to changes in aerobic fitness than FMD.

Corticosterone, but not Glucose, Treatment Enables Fasted Adrenalectomized Rats to Survive Moderate Hemorrhage

NASA Technical Reports Server (NTRS)

Darlington, Daniel N.; Chew, Gordon; Ha, Taryn; Keil, Lanny C.; Dallman, Mary F.

1990-01-01

Fed adrenalectomized rats survive the stress of hemorrhage and hypovolemia, whereas fasted adrenalectomized rats become hypotensive and hypoglycemic after the first 90 min and die within 4 hours (h). We have studied the effects of glucose and corticosterone (B) infusions after hemorrhage as well as treatment with B at the time of adrenalectomy on the capacity of chronically prepared, conscious, fasted, adrenalectomized rats to survive hemorrhage. We have also measured the magnitudes of vasoactive hormone responses to hemorrhage. Maintenance of plasma glucose concentrations did not sustain life; however, treatment of rats at the time of adrenalectomy with B allowed 100 percent survival, and acute treatment of adrenalectomized rats at the time of hemorrhage allowed about 50 percent survival during the 5-h posthemorrhage observation period. Rats in the acute B infusion group that died exhibited significantly increased plasma B and significantly decreased plasma glucose concentrations by 2 h compared to the rats that lived. Plasma vasopressin, renin, and norepinephrine responses to hemorrhage were markedly augmented in the adrenalectomized rats not treated with B, and plasma vasopressin concentrations were significantly elevated at 1 and 2 h in all of the rats that subsequently died compared to values in those that lived. We conclude that: 1) death after hemorrhage in fasted adrenalectomized rats is not a result of lack of glucose; 2) chronic and, to an extent, acute treatment of fasted adrenalectomized rats with B enables survival; 3) fasted adrenalectomized rats exhibit strong evidence of hepatic insufficiency which is not apparent in either fed adrenalectomized rats or B-treated fasted adrenalectomized rats; 4) death after hemorrhage in fasted adrenalectomized rats may result from hepatic failure as a consequence of marked splanchnic vasoconstriction mediated bv the actions of extraordinarily high levels of vasoactive hormones after hemorrhage; and 5) B appears to act to decrease the magnitude of response of vasoactive hormones after hemorrhage in fasted adrenatectomized rats.

Unusual intraosseous fossilized soft tissues from the Middle Triassic Nothosaurus bone

NASA Astrophysics Data System (ADS)

Surmik, Dawid; Rothschild, Bruce M.; Pawlicki, Roman

2017-04-01

Fossilized soft tissues, occasionally found together with skeletal remains, provide insights to the physiology and functional morphology of extinct organisms. Herein, we present unusual fossilized structures from the cortical region of bone identified in isolated skeletal remains of Middle Triassic nothosaurs from Upper Silesia, Poland. The ribbed or annuli-shaped structures have been found in a sample of partially demineralized coracoid and are interpreted as either giant red blood cells or as blood vessel walls. The most probable function is reinforcing the blood vessels from changes of nitrogen pressure in air-breathing diving reptiles. These structures seem to have been built of extensible muscle layers which prevent the vessel damage during rapid ascent. Such suspected function presented here is parsimonious with results of previous studies, which indicate rarity of the pathological modification of bones associated with decompression syndrome in Middle Triassic nothosaurs.

Supervised retinal vessel segmentation from color fundus images based on matched filtering and AdaBoost classifier.

PubMed

Memari, Nogol; Ramli, Abd Rahman; Bin Saripan, M Iqbal; Mashohor, Syamsiah; Moghbel, Mehrdad

2017-01-01

The structure and appearance of the blood vessel network in retinal fundus images is an essential part of diagnosing various problems associated with the eyes, such as diabetes and hypertension. In this paper, an automatic retinal vessel segmentation method utilizing matched filter techniques coupled with an AdaBoost classifier is proposed. The fundus image is enhanced using morphological operations, the contrast is increased using contrast limited adaptive histogram equalization (CLAHE) method and the inhomogeneity is corrected using Retinex approach. Then, the blood vessels are enhanced using a combination of B-COSFIRE and Frangi matched filters. From this preprocessed image, different statistical features are computed on a pixel-wise basis and used in an AdaBoost classifier to extract the blood vessel network inside the image. Finally, the segmented images are postprocessed to remove the misclassified pixels and regions. The proposed method was validated using publicly accessible Digital Retinal Images for Vessel Extraction (DRIVE), Structured Analysis of the Retina (STARE) and Child Heart and Health Study in England (CHASE_DB1) datasets commonly used for determining the accuracy of retinal vessel segmentation methods. The accuracy of the proposed segmentation method was comparable to other state of the art methods while being very close to the manual segmentation provided by the second human observer with an average accuracy of 0.972, 0.951 and 0.948 in DRIVE, STARE and CHASE_DB1 datasets, respectively.

Streamlined vessels for speedboats: Macro modifications of shark skin design applications

NASA Astrophysics Data System (ADS)

Ibrahim, M. D.; Amran, S. N. A.; Zulkharnain, A.; Sunami, Y.

2018-01-01

Functional properties of shark denticles have caught the attention of engineers and scientist today due to the hydrodynamic effects of its skin surface roughness. The skin of a fast swimming shark reveals riblet structures that help to reduce skin friction drag, shear stresses, making its movement to be more efficient and faster. Inspired by the structure of the shark skin denticles, our team has conducted a study on alternative on improving the hydrodynamic design of marine vessels by applying the simplified version of shark skin skin denticles on the surface hull of the vessels. Models used for this study are constructed and computational fluid dynamic (CFD) simulations are then carried out to predict the effectiveness of the hydrodynamic effects of the biomimetic shark skins on those models. Interestingly, the numerical calculated results obtained shows that the presence of biomimetic shark skin implemented on the vessels give improvements in the maximum speed as well as reducing the drag force experience by the vessels. The pattern of the wave generated post cruising area behind the vessels can also be observed to reduce the wakes and eddies. Theoretically, reduction of drag force provides a more efficient vessel with a better cruising speed. To further improve on this study, the authors are now actively arranging an experimental procedure in order to verify the numerical results obtained by CFD. The experimental test will be carried out using an 8 metre flow channel provided by University Malaysia Sarawak, Malaysia.

Mechanical Behavior of A Metal Composite Vessels Under Pressure At Cryogenic Temperatures

NASA Astrophysics Data System (ADS)

Tsaplin, A. I.; Bochkarev, S. V.

2016-01-01

Results of an experimental investigation into the deformation and destruction of a metal composite vessel with a cryogenic gas are presented. Its structure is based on basalt, carbon, and organic fibers. The vessel proved to be serviceable at cryogenic temperatures up to a burst pressure of 45 MPa, and its destruction was without fragmentation. A mathematical model adequately describing the rise of pressure in the cryogenic vessel due to the formation of a gaseous phase upon boiling of the liquefied natural gas during its storage without drainage at the initial stage is proposed.

Segmentation of retinal blood vessels using artificial neural networks for early detection of diabetic retinopathy

NASA Astrophysics Data System (ADS)

Mann, Kulwinder S.; Kaur, Sukhpreet

2017-06-01

There are various eye diseases in the patients suffering from the diabetes which includes Diabetic Retinopathy, Glaucoma, Hypertension etc. These all are the most common sight threatening eye diseases due to the changes in the blood vessel structure. The proposed method using supervised methods concluded that the segmentation of the retinal blood vessels can be performed accurately using neural networks training. It uses features which include Gray level features; Moment Invariant based features, Gabor filtering, Intensity feature, Vesselness feature for feature vector computation. Then the feature vector is calculated using only the prominent features.

Effects of vasoactive intestinal peptide, helodermin and galanin on responses of guinea-pig lung parenchyma to histamine, acetylcholine and leukotriene D4.

PubMed Central

Conroy, D. M.; Samhoun, M. N.; Piper, P. J.

1991-01-01

1. The effect of vasoactive intestinal peptide (VIP) was studied on the contractile response of guinea-pig lung parenchymal strips (GPP) induced by bronchoconstrictor agonists, such as leukotriene D4 (LTD4), histamine and acetylcholine (ACh). This effect of VIP was compared with helodermin, a peptide that is structurally related to VIP, and galanin, another neuropeptide that is thought to co-exist with VIP. 2. VIP (10 nM) induced a potent and reversible inhibition of the contractions of GPP induced by LTD4 (1-30 pmol) but did not affect those due to ACh (1-100 nmol) or histamine (1-30 nmol). A ten fold higher concentration of VIP (100 nM) did not further inhibit LTD4-induced responses or reduce those induced by histamine or ACh. 3. Helodermin (10 nM) had a similar inhibitory effect on contractions of GPP induced by LTD4 (3-30 pmol) but did not affect contractions induced by histamine (1-10 nmol). 4. Indomethacin (2.8 microM) and salbutamol (10 nM) significantly reduced responses elicited by LTD4 and histamine but not those due to ACh. A ten fold higher concentration of salbutamol (100 nM) further inhibited the contractions due to LTD4 and histamine and at this concentration responses induced by ACh were inhibited. 5. VIP (10 nM) and helodermin (10 nM) significantly reduced the LTD4-induced release of thromboxane A2 (TXA2), measured as TxB2 by radioimmunoassay, from GPP. The smaller release of TxA2 induced by histamine was not significantly reduced in the presence of VIP. 6. In comparative studies, galanin (10-100 nM) did not affect contractions of GPP induced by either LTD4, histamine or ACh.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1725762

Preoperative carbohydrate load and intraoperatively infused omega-3 polyunsaturated fatty acids positively impact nosocomial morbidity after coronary artery bypass grafting: a double-blind controlled randomized trial.

PubMed

Feguri, Gibran Roder; de Lima, Paulo Ruiz Lúcio; de Cerqueira Borges, Danilo; Toledo, Laura Ramos; Batista, Larissa Nadaf; E Silva, Thaís Carvalho; Segri, Neuber José; de Aguilar-Nascimento, José Eduardo

2017-04-20

A strategy of limited preoperative fasting, with carbohydrate (CHO) loading and intraoperative infusion of omega-3 polyunsaturated fatty acids (ω-3 PUFA), has seldom been tried in cardiovascular surgery. Brief fasting, followed by CHO intake 2 h before anesthesia, may improve recovery from CABG procedures and lower perioperative vasoactive drug requirements. Infusion of ω-3 PUFA may reduce occurrences of postoperative atrial fibrillation (POAF) and shorten hospital stays. The aim of this study was to assess morbidity (especially POAF) in ICU patients after coronary artery bypass grafting (CABG)/cardiopulmonary bypass (CPB) in combination, if preoperative fasts are curtailed in favor of CHO loading, and ω-3 PUFA are infused intraoperatively. Fifty-seven patients undergoing CABG were randomly assigned to receive 12.5% maltodextrin (200 ml, 2 h before anesthesia), without infusing ω-3 PUFA (CHO, n = 14); water (200 ml, 2 h before anesthesia), without infusing ω-3 PUFA (controls, n = 14); 12.5% maltodextrin (200 ml, 2 h before anesthesia) plus intraoperative ω-3 PUFA (0.2 mcg/kg) (CHO + W3, n = 15); or water (200 ml, 2 h before anesthesia) plus intraoperative ω-3 PUFA (0.2 mcg/kg) (W3, n = 14). Perioperative clinical variables and mortality were analyzed, examining the incidence of POAF, as well as the need for inotropic vasoactive drugs during surgery and in ICU. Two deaths occurred (3.5%), but there were no instances of bronchoaspiration and mediastinitis. Neither ICU stays nor total postoperative stays differed by group (P > 0.05). Patients given preoperative CHO loads (CHO and CHO + W3 groups) experienced fewer instances of hospital infection (RR = 0.29, 95%CI 0.09-0.94; P = 0.023) and were less reliant on vasoactive amines during surgery (RR = 0.60, 95% CI 0.38-0.94; P = 0.020). Similarly, the number of patients requiring vasoactive drugs while recovering in ICU differed significantly by group (P = 0.008), showing benefits in patients given CHO loads. The overall incidence of POAF was 29.8% (17/57), differing significantly by group (P = 0.009). Groups given ω-3 PUFA (W3 and CHO + W3 groups) experienced significantly fewer instances of POAF (RR = 4.83, 95% CI 1.56-15.02; P = 0.001). Preoperative curtailment of fasting was safe in this cohort. When implemented in conjunction with CHO loading and infusion of ω-3 PUFA during surgery, expedited recovery from CABG with CPB was observed. NCT: 03017001.

Retinal vessel tortuosity measures and their applications.

PubMed

Kalitzeos, Angelos A; Lip, Gregory Y H; Heitmar, Rebekka

2013-01-01

Structural retinal vascular characteristics, such as vessel calibers, tortuosity and bifurcation angles are increasingly quantified in an objective manner, slowly replacing subjective qualitative disease classification schemes. This paper provides an overview of the current methodologies and calculations used to compute retinal vessel tortuosity. We set out the different parameter calculations and provide an insight into the clinical applications, while critically reviewing its pitfalls and shortcomings. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inflatable Launch and Recovery System

DTIC Science & Technology

2014-07-31

clamping fixture connects the ramp structure to the vessel. A snubber element dampens vibrations and transient tow loads. Unclassified Unclassified...integrated dynamic snubber element to dampen out vibrations and transient tow loads. The main air fill line from the handling system to the inflatable ramp...of the vessel A with standard container cam locks 12a (two of which are shown in phantom in FIG. 1). The system 10 can connect to a vessel power

Automated segmentation of hepatic vessel trees in non-contrast x-ray CT images

NASA Astrophysics Data System (ADS)

Kawajiri, Suguru; Zhou, Xiangrong; Zhang, Xuejin; Hara, Takeshi; Fujita, Hiroshi; Yokoyama, Ryujiro; Kondo, Hiroshi; Kanematsu, Masayuki; Hoshi, Hiroaki

2007-03-01

Hepatic vessel trees are the key structures in the liver. Knowledge of the hepatic vessel trees is important for liver surgery planning and hepatic disease diagnosis such as portal hypertension. However, hepatic vessels cannot be easily distinguished from other liver tissues in non-contrast CT images. Automated segmentation of hepatic vessels in non-contrast CT images is a challenging issue. In this paper, an approach for automated segmentation of hepatic vessels trees in non-contrast X-ray CT images is proposed. Enhancement of hepatic vessels is performed using two techniques: (1) histogram transformation based on a Gaussian window function; (2) multi-scale line filtering based on eigenvalues of Hessian matrix. After the enhancement of hepatic vessels, candidate of hepatic vessels are extracted by thresholding. Small connected regions of size less than 100 voxels are considered as false-positives and are removed from the process. This approach is applied to 20 cases of non-contrast CT images. Hepatic vessel trees segmented from the contrast-enhanced CT images of the same patient are used as the ground truth in evaluating the performance of the proposed segmentation method. Results show that the proposed method can enhance and segment the hepatic vessel regions in non-contrast CT images correctly.

46 CFR 175.540 - Equivalents.

Code of Federal Regulations, 2010 CFR

2010-10-01

... safety management system is in place on board a vessel. The Commandant will consider the size and corporate structure of a vessel's company when determining the acceptability of an equivalent system... require engineering evaluations and tests to demonstrate the equivalence of the substitute. (b) The...

Stress analysis and evaluation of a rectangular pressure vessel

NASA Astrophysics Data System (ADS)

Rezvani, M. A.; Ziada, H. H.; Shurrab, M. S.

1992-10-01

This study addresses structural analysis and evaluation of an abnormal rectangular pressure vessel, designed to house equipment for drilling and collecting samples from Hanford radioactive waste storage tanks. It had to be qualified according to ASME boiler and pressure vessel code, section 8; however, it had the cover plate bolted along the long face, a configuration not addressed by the code. Finite element method was used to calculate stresses resulting from internal pressure; these stresses were then used to evaluate and qualify the vessel. Fatigue is not a concern; thus, it can be built according to section 8, division 1 instead of division 2. Stress analysis was checked against the code. A stayed plate was added to stiffen the long side of the vessel.

High temperature superconducting Maglev equipment on vehicle

NASA Astrophysics Data System (ADS)

Wang, S. Y.; Wang, J. S.; Ren, Z. Y.; Zhu, M.; Jiang, H.; Wang, X. R.; Shen, X. M.; Song, H. H.

2003-04-01

Onboard high temperature superconducting (HTS) Maglev equipment is a heart part of a HTS Maglev vehicle, which is composed of YBaCuO bulks and rectangle-shape liquid nitrogen vessel and used successfully in the first manned HTS Maglev test vehicle. Arrangement of YBaCuO bulks in liquid nitrogen vessel, structure of the vessel, levitation forces of a single vessel and two vessels, and total levitation force are reported. The first manned HTS Maglev test vehicle in the world has operated well more than one year after it was born on Dec. 31, 2000, and more than 23,000 passengers have taken the vehicle till now. Well operation of more than one year proves the reliability of the onboard HTS Maglev equipment.

Occipital foramina development involves localised regulation of mesenchyme proliferation and is independent of apoptosis

PubMed Central

Akbareian, Sophia E; Pitsillides, Andrew A; Macharia, Raymond G; McGonnell, Imelda M

2015-01-01

Cranial foramina are holes within the skull, formed during development, allowing entry and exit of blood vessels and nerves. Once formed they must remain open, due to the vital structures they contain, i.e. optic nerves, jugular vein, carotid artery, and other cranial nerves and blood vessels. Understanding cranial foramina development is essential as cranial malformations lead to the stenosis or complete closure of these structures, resulting in blindness, deafness, facial paralysis, raised intracranial pressure and lethality. Here we focus on describing early events in the formation of the jugular, carotid and hypoglossal cranial foramina that form in the mesoderm-derived, endochondral occipital bones at the base of the embryonic chick skull. Whole-mount skeletal staining of skulls indicates the appearance of these foramina from HH32/D7.5 onwards. Haematoxylin & eosin staining of sections shows that the intimately associated mesenchyme, neighbouring the contents of these cranial foramina, is initially very dense and gradually becomes sparser as development proceeds. Histological examination also revealed that these foramina initially contain relatively large-diameter nerves, which later become refined, and are closely associated with the blood vessel, which they also innervate within the confines of the foramina. Interestingly cranial foramina in the base of the skull contain blood vessels lacking smooth muscle actin, which suggests these blood vessels belong to glomus body structures within the foramina. The blood vessel shape also appears to dictate the overall shape of the resulting foramina. We initially hypothesised that cranial foramina development could involve targeted proliferation and local apoptosis to cause ‘mesenchymal clearing’ and the creation of cavities in a mechanism similar to joint cavitation. We find that this is not the case, and propose that a mechanism reliant upon local nerve/blood vessel-derived restriction of ossification may contribute to foramina formation during cranial development. PMID:25994127

On the linear stability of blood flow through model capillary networks.

PubMed

Davis, Jeffrey M

2014-12-01

Under the approximation that blood behaves as a continuum, a numerical implementation is presented to analyze the linear stability of capillary blood flow through model tree and honeycomb networks that are based on the microvascular structures of biological tissues. The tree network is comprised of a cascade of diverging bifurcations, in which a parent vessel bifurcates into two descendent vessels, while the honeycomb network also contains converging bifurcations, in which two parent vessels merge into one descendent vessel. At diverging bifurcations, a cell partitioning law is required to account for the nonuniform distribution of red blood cells as a function of the flow rate of blood into each descendent vessel. A linearization of the governing equations produces a system of delay differential equations involving the discharge hematocrit entering each network vessel and leads to a nonlinear eigenvalue problem. All eigenvalues in a specified region of the complex plane are captured using a transformation based on contour integrals to construct a linear eigenvalue problem with identical eigenvalues, which are then determined using a standard QR algorithm. The predicted value of the dimensionless exponent in the cell partitioning law at the instability threshold corresponds to a supercritical Hopf bifurcation in numerical simulations of the equations governing unsteady blood flow. Excellent agreement is found between the predictions of the linear stability analysis and nonlinear simulations. The relaxation of the assumption of plug flow made in previous stability analyses typically has a small, quantitative effect on the stability results that depends on the specific network structure. This implementation of the stability analysis can be applied to large networks with arbitrary structure provided only that the connectivity among the network segments is known.

Tie-fibre structure and organization in the knee menisci

PubMed Central

Andrews, Stephen H J; Rattner, Jerome B; Abusara, Ziad; Adesida, Adetola; Shrive, Nigel G; Ronsky, Janet L

2014-01-01

The collagenous structure of the knee menisci is integral to the mechanical integrity of the tissue and the knee joint. The tie-fibre structure of the tissue has largely been neglected, despite previous studies demonstrating its correlation with radial stiffness. This study has evaluated the structure of the tie-fibres of bovine menisci using 2D and 3D microscopy techniques. Standard collagen and proteoglycan (PG) staining and 2D light microscopy techniques were conducted. For the first time, the collagenous structure of the menisci was evaluated using 3D, second harmonic generation (SHG) microscopy. This technique facilitated the imaging of collagen structure in thick sections (50–100 μm). Imaging identified that tie-fibres of the menisci arborize from the outer margin of the meniscus toward the inner tip. This arborization is associated with the structural arrangement of the circumferential fibres. SHG microscopy has definitively demonstrated the 3D organization of tie-fibres in both sheets and bundles. The hierarchy of the structure is related to the organization of circumferential fascicles. Large tie-fibre sheets bifurcate into smaller sheets to surround circumferential fascicles of decreasing size. The tie-fibres emanate from the lamellar layer that appears to surround the entire meniscus. At the tibial and femoral surfaces these tie-fibre sheets branch perpendicularly into the meniscal body. The relationship between tie-fibres and blood vessels in the menisci was also observed in this study. Tie-fibre sheets surround the blood vessels and an associated PG-rich region. This subunit of the menisci has not previously been described. The size of tie-fibre sheets surrounding the vessels appeared to be associated with the size of blood vessel. These structural findings have implications in understanding the mechanics of the menisci. Further, refinement of the complex structure of the tie-fibres is important in understanding the consequences of injury and disease in the menisci. The framework of meniscus architecture also defines benchmarks for the development of tissue-engineered replacements in the future. PMID:24617800

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.

Hemodynamics

PubMed Central

Secomb, Timothy W.

2016-01-01

A review is presented of the physical principles governing the distribution of blood flow and blood pressure in the vascular system. The main factors involved are the pulsatile driving pressure generated by the heart, the flow characteristics of blood, and the geometric structure and mechanical properties of the vessels. The relationship between driving pressure and flow in a given vessel can be understood by considering the viscous and inertial forces acting on the blood. Depending on the vessel diameter and other physical parameters, a wide variety of flow phenomena can occur. In large arteries, the propagation of the pressure pulse depends on the elastic properties of the artery walls. In the microcirculation, the fact that blood is a suspension of cells strongly influences its flow properties and leads to a non-uniform distribution of hematocrit among microvessels. The forces acting on vessel walls include shear stress resulting from blood flow and circumferential stress resulting from blood pressure. Biological responses to these forces are important in the control of blood flow and the structural remodeling of vessels, and also play a role in major disease processes including hypertension and atherosclerosis. Consideration of hemodynamics is essential for a comprehensive understanding of the functioning of the circulatory system. PMID:27065172

Development of heat transfer enhancement techniques for external cooling of an advanced reactor vessel

NASA Astrophysics Data System (ADS)

Yang, Jun

Nucleate boiling is a well-recognized means for passively removing high heat loads (up to ˜106 W/m2) generated by a molten reactor core under severe accident conditions while maintaining relatively low reactor vessel temperature (<800 °C). With the upgrade and development of advanced power reactors, however, enhancing the nucleate boiling rate and its upper limit, Critical Heat Flux (CHF), becomes the key to the success of external passive cooling of reactor vessel undergoing core disrupture accidents. In the present study, two boiling heat transfer enhancement methods have been proposed, experimentally investigated and theoretically modelled. The first method involves the use of a suitable surface coating to enhance downward-facing boiling rate and CHF limit so as to substantially increase the possibility of reactor vessel surviving high thermal load attack. The second method involves the use of an enhanced vessel/insulation design to facilitate the process of steam venting through the annular channel formed between the reactor vessel and the insulation structure, which in turn would further enhance both the boiling rate and CHF limit. Among the various available surface coating techniques, metallic micro-porous layer surface coating has been identified as an appropriate coating material for use in External Reactor Vessel Cooling (ERVC) based on the overall consideration of enhanced performance, durability, the ease of manufacturing and application. Since no previous research work had explored the feasibility of applying such a metallic micro-porous layer surface coating on a large, downward facing and curved surface such as the bottom head of a reactor vessel, a series of characterization tests and experiments were performed in the present study to determine a suitable coating material composition and application method. Using the optimized metallic micro-porous surface coatings, quenching and steady-state boiling experiments were conducted in the Sub-scale Boundary Layer Boiling (SBLB) test facility at Penn State to investigate the nucleate boiling and CHF enhancement effects of the surface coatings by comparing the measurements with those for a plain vessel without coatings. An overall enhancement in nucleate boiling rates and CHF limits up to 100% were observed. Moreover, combination of data from quenching experiments and steady-state experiments produced new sets of boiling curves, which covered both the nucleate and transient boiling regimes with much greater accuracy. Beside the experimental work, a theoretical CHF model has also been developed by considering the vapor dynamics and the boiling-induced two-phase motions in three separate regions adjacent to the heating surface. The CHF model is capable of predicting the performance of micro-porous coatings with given particle diameter, porosity, media permeability and thickness. It is found that the present CHF model agrees favorably with the experimental data. Effects of an enhanced vessel/insulation structure on the local nucleate boiling rate and CHF limit have also been investigated experimentally. It is observed that the local two-phase flow quantities such as the local void fraction, quality, mean vapor velocity, mean liquid velocity, and mean vapor and liquid mass flow rates could have great impact on the local surface heat flux as boiling of water takes place on the vessel surface. An upward co-current two-phase flow model has been developed to predict the local two-phase flow behavior for different flow channel geometries, which are set by the design of insulation structures. It is found from the two-phase flow visualization experiments and the two-phase flow model calculations that the enhanced vessel/insulation structure greatly improved the steam venting process at the minimum gap location compared to the performance of thermal insulation structures without enhancement. Moveover, depending on the angular location, steady-state boiling experiments with the enhanced insulation design showed an enhancement of 1.8 to 3.0 times in the local critical heat flux. Finally, nucleate boiling and CHF correlations were developed based on the data obtained from various quenching and steady-state boiling experiments. Additionally, CHF enhancement factors were determined and examined to show the separate and integral effects of the two ERVC enhancement methods. When both vessel coating and insulation structure were used simultaneously, the integral effect on CHF enhancement was found much less than the product of the two separate effects, indicating possible competing mechanisms (i.e., interference) between the two enhancement methods.

Large Extremity Peripheral Nerve Repair

DTIC Science & Technology

2014-10-01

has also been shown to produce human-beta-3-defensin. These antimicrobial peptides are implicated in the resistance of epithelial surfaces to...gonadotrophin receptors that regulate prostaglandin production and activity. Epithelial cells manufacture multiple vasoactive peptides , growth factors...200734 P-RCT (n Z 102) PT burns Processed Amnion vs topical antimicrobials . Significantly less dressing changes with amnion. Time to healing, length

A Practical Method for No-Reflow Treatment

PubMed Central

Cetin, Mustafa; Kiziltunc, Emrullah; Güven Cetin, Zehra; Kundi, Harun; Gulkan, Birsen; Cicekcioglu, Hülya

2016-01-01

No-reflow is an undesirable result of percutaneous coronary interventions. Vasoactive drug administration at the distal part of the coronary artery is suggested as a therapeutic option for no-reflow treatment. Here, we represent two cases of successful no-reflow management with previously used monorail balloon at the same procedure as a hand-made distal infusion catheter. PMID:26981291

A Practical Method for No-Reflow Treatment.

PubMed

Cetin, Mustafa; Kiziltunc, Emrullah; Güven Cetin, Zehra; Kundi, Harun; Gulkan, Birsen; Cicekcioglu, Hülya

2016-01-01

No-reflow is an undesirable result of percutaneous coronary interventions. Vasoactive drug administration at the distal part of the coronary artery is suggested as a therapeutic option for no-reflow treatment. Here, we represent two cases of successful no-reflow management with previously used monorail balloon at the same procedure as a hand-made distal infusion catheter.

Vascular mimicry in glioblastoma following anti-angiogenic and anti-20-HETE therapies.

PubMed

Angara, Kartik; Rashid, Mohammad H; Shankar, Adarsh; Ara, Roxan; Iskander, Asm; Borin, Thaiz F; Jain, Meenu; Achyut, Bhagelu R; Arbab, Ali S

2017-09-01

Glioblastoma (GBM) is one hypervascular and hypoxic tumor known among solid tumors. Antiangiogenic therapeutics (AATs) have been tested as an adjuvant to normalize blood vessels and control abnormal vasculature. Evidence of relapse exemplified in the progressive tumor growth following AAT reflects development of resistance to AATs. Here, we identified that GBM following AAT (Vatalanib) acquired an alternate mechanism to support tumor growth, called vascular mimicry (VM). We observed that Vatalanib induced VM vessels are positive for periodic acid-Schiff (PAS) matrix but devoid of any endothelium on the inner side and lined by tumor cells on the outer-side. The PAS+ matrix is positive for basal laminae (laminin) indicating vascular structures. Vatalanib treated GBM displayed various stages of VM such as initiation (mosaic), sustenance, and full-blown VM. Mature VM structures contain red blood cells (RBC) and bear semblance to the functional blood vessel-like structures, which provide all growth factors to favor tumor growth. Vatalanib treatment significantly increased VM especially in the core of the tumor, where HIF-1α was highly expressed in tumor cells. VM vessels correlate with hypoxia and are characterized by co-localized MHC-1+ tumor and HIF-1α expression. Interestingly, 20-HETE synthesis inhibitor HET0016 significantly decreased GBM tumors through decreasing VM structures both at the core and at periphery of the tumors. In summary, AAT induced resistance characterized by VM is an alternative mechanism adopted by tumors to make functional vessels by transdifferentiation of tumor cells into endothelial-like cells to supply nutrients in the event of hypoxia. AAT induced VM is a potential therapeutic target of the novel formulation of HET0016. Our present study suggests that HET0016 has a potential to target therapeutic resistance and can be combined with other antitumor agents in preclinical and clinical trials.

Assuring Structural Integrity in Army Systems

DTIC Science & Technology

1985-02-28

power plants are* I. American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code , Section III - Rules for Construction of Nuclear...Power Plant Components; 2. ASNE Boiler and Pressure Vessel Code , Section XI, Rules for In-Service Inspection of Nuclear Power Plant Components; and 3

46 CFR 189.40-5 - Notice and plans required.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS INSPECTION... examination, or underwater survey or whenever repairs are made to the vessel's hull. (c) Each barge that holds... barge undergoes a drydock examination, internal structural examination, or underwater survey or whenever...

46 CFR 189.40-5 - Notice and plans required.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS INSPECTION... examination, or underwater survey or whenever repairs are made to the vessel's hull. (c) Each barge that holds... barge undergoes a drydock examination, internal structural examination, or underwater survey or whenever...

46 CFR 189.40-5 - Notice and plans required.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS INSPECTION... examination, or underwater survey or whenever repairs are made to the vessel's hull. (c) Each barge that holds... barge undergoes a drydock examination, internal structural examination, or underwater survey or whenever...

46 CFR 189.40-5 - Notice and plans required.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS INSPECTION... examination, or underwater survey or whenever repairs are made to the vessel's hull. (c) Each barge that holds... barge undergoes a drydock examination, internal structural examination, or underwater survey or whenever...

46 CFR 189.40-5 - Notice and plans required.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS INSPECTION... examination, or underwater survey or whenever repairs are made to the vessel's hull. (c) Each barge that holds... barge undergoes a drydock examination, internal structural examination, or underwater survey or whenever...

Hanging core support system for a nuclear reactor

DOEpatents

Burelbach, James P.; Kann, William J.; Pan, Yen-Cheng; Saiveau, James G.; Seidensticker, Ralph W.

1987-01-01

For holding the reactor core in the confining reactor vessel, a support is disclosed that is structurally independent of the vessel, that is dimensionally accurate and stable, and that comprises tandem tension linkages that act redundantly of one another to maintain stabilized core support even in the unlikely event of the complete failure of one of the linkages. The core support has a mounting platform for the reactor core, and unitary structure including a flange overlying the top edge of the reactor vessels, and a skirt and box beams between the flange and platform for establishing one of the linkages. A plurality of tension rods connect between the deck closing the reactor vessel and the platform for establishing the redundant linkage. Loaded Belleville springs flexibly hold the tension rods at the deck and separable bayonet-type connections hold the tension rods at the platform. Motion or radiation sensing detectors can be provide at the lower ends of the tension rods for obtaining pertinent readings proximate the core.

Heat barrier for use in a nuclear reactor facility

DOEpatents

Keegan, Charles P.

1988-01-01

A thermal barrier for use in a nuclear reactor facility is disclosed herein. Generally, the thermal barrier comprises a flexible, heat-resistant web mounted over the annular space between the reactor vessel and the guard vessel in order to prevent convection currents generated in the nitrogen atmosphere in this space from entering the relatively cooler atmosphere of the reactor cavity which surrounds these vessels. Preferably, the flexible web includes a blanket of heat-insulating material formed from fibers of a refractory material, such as alumina and silica, sandwiched between a heat-resistant, metallic cloth made from stainless steel wire. In use, the web is mounted between the upper edges of the guard vessel and the flange of a sealing ring which surrounds the reactor vessel with a sufficient enough slack to avoid being pulled taut as a result of thermal differential expansion between the two vessels. The flexible web replaces the rigid and relatively complicated structures employed in the prior art for insulating the reactor cavity from the convection currents generated between the reactor vessel and the guard vessel.

Heterogeneity of the tumor vasculature.

PubMed

Nagy, Janice A; Chang, Sung-Hee; Shih, Shou-Ching; Dvorak, Ann M; Dvorak, Harold F

2010-04-01

The blood vessels supplying tumors are strikingly heterogeneous and differ from their normal counterparts with respect to organization, structure, and function. Six distinctly different tumor vessel types have been identified, and much has been learned about the steps and mechanisms by which they form. Four of the six vessel types (mother vessels, capillaries, glomeruloid microvascular proliferations, and vascular malformations) develop from preexisting normal venules and capillaries by angiogenesis. The two remaining vessel types (feeder arteries and draining veins) develop from arterio-venogenesis, a parallel, poorly understood process that involves the remodeling of preexisting arteries and veins. All six of these tumor vessel types can be induced to form sequentially in normal mouse tissues by an adenoviral vector expressing vascular endothelial growth factor (VEGF)-A164. Current antiangiogenic cancer therapies directed at VEGF-A or its receptors have been of only limited benefit to cancer patients, perhaps because they target only the endothelial cells of the tumor blood vessel subset that requires exogenous VEGF-A for maintenance. A goal of future work is to identify therapeutic targets on tumor blood vessel endothelial cells that have lost this requirement. Thieme Medical Publishers.

Heterogeneity of the Tumor Vasculature

PubMed Central

Nagy, Janice A.; Chang, Sung-Hee; Shih, Shou-Ching; Dvorak, Ann M.; Dvorak, Harold F.

2012-01-01

The blood vessels supplying tumors are strikingly heterogeneous and differ from their normal counterparts with respect to organization, structure, and function. Six distinctly different tumor vessel types have been identified, and much has been learned about the steps and mechanisms by which they form. Four of the six vessel types (mother vessels, capillaries, glomeruloid microvascular proliferations, and vascular malformations) develop from preexisting normal venules and capillaries by angiogenesis. The two remaining vessel types (feeder arteries and draining veins) develop from arterio-venogenesis, a parallel, poorly understood process that involves the remodeling of preexisting arteries and veins. All six of these tumor vessel types can be induced to form sequentially in normal mouse tissues by an adenoviral vector expressing vascular endothelial growth factor (VEGF)-A164. Current antiangiogenic cancer therapies directed at VEGF-A or its receptors have been of only limited benefit to cancer patients, perhaps because they target only the endothelial cells of the tumor blood vessel subset that requires exogenous VEGF-A for maintenance. A goal of future work is to identify therapeutic targets on tumor blood vessel endothelial cells that have lost this requirement. PMID:20490982

Fracture resistance of welded thick-walled high-pressure vessels in power plants. Report No. 2. Approach to evaluating static strength

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

Gorynin, I.V.; Filatov, V.M.; Ignatov, V.A.

1986-07-01

The authors examine data on the effect of defects on the fracture resistance of high-pressure vessels and their models obtained within the framework of the HSST program. Results of internal-pressure tests of two types of vessels with a wall thickness of 152 mm made from forgings of steels SA508 and SA533, as well as small vessels with a wall thickness of 11.5 and 23mm made of steel SA533 are shown. The authors state that testing thick-walled welded high-pressure vessels and thin-walled vessels with surface defects of different sizes has demonstrated that there are substantial static-strength reserves in structures designed bymore » existing domestic and foreign standards on the strength of power-plant equipment. A correction was proposed for the presently used method of calculating the resistance of highpressure vessels to brittle fracture that allows for the dimensions of the defects in relation to the type of vessel, the manufacturing technology, and the method of inspection.« less

A bill to amend title 46, United States Code, to exempt old vessels that only operate within inland waterways from the fire-retardant materials requirement if the owners of such vessels make annual structural alterations to at least 10 percent of the areas of the vessels that are not constructed of fire-retardant materials.

THOMAS, 113th Congress

Sen. Brown, Sherrod [D-OH

2014-11-13

Senate - 11/13/2014 Read twice and referred to the Committee on Commerce, Science, and Transportation. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Pressure vessel fracture, fatigue, and life management: PVP-Volume 233

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

Bhandari, S.; Milella, P.P.; Pennell, W.E.

1992-01-01

This volume contains papers relating to the structural integrity assessment of pressure vessels and piping, with special emphasis on the effects of aging. The papers are organized in the following five areas: (1) pressure vessel life management; (2) fracture characterization using local and dual-parameter approaches; (3) stratification and thermal fatigue; (4) creep, fatigue, and fracture; and (5) integrated approach to integrity assessment of pressure components. Separate abstracts were prepared for 39 papers in this conference.

Automated segmentation of middle hepatic vein in non-contrast x-ray CT images based on an atlas-driven approach

NASA Astrophysics Data System (ADS)

Kitagawa, Teruhiko; Zhou, Xiangrong; Hara, Takeshi; Fujita, Hiroshi; Yokoyama, Ryujiro; Kondo, Hiroshi; Kanematsu, Masayuki; Hoshi, Hiroaki

2008-03-01

In order to support the diagnosis of hepatic diseases, understanding the anatomical structures of hepatic lobes and hepatic vessels is necessary. Although viewing and understanding the hepatic vessels in contrast media-enhanced CT images is easy, the observation of the hepatic vessels in non-contrast X-ray CT images that are widely used for the screening purpose is difficult. We are developing a computer-aided diagnosis (CAD) system to support the liver diagnosis based on non-contrast X-ray CT images. This paper proposes a new approach to segment the middle hepatic vein (MHV), a key structure (landmark) for separating the liver region into left and right lobes. Extraction and classification of hepatic vessels are difficult in non-contrast X-ray CT images because the contrast between hepatic vessels and other liver tissues is low. Our approach uses an atlas-driven method by the following three stages. (1) Construction of liver atlases of left and right hepatic lobes using a learning datasets. (2) Fully-automated enhancement and extraction of hepatic vessels in liver regions. (3) Extraction of MHV based on the results of (1) and (2). The proposed approach was applied to 22 normal liver cases of non-contrast X-ray CT images. The preliminary results show that the proposed approach achieves the success in 14 cases for MHV extraction.

Segmentation of vessels: the corkscrew algorithm

NASA Astrophysics Data System (ADS)

Wesarg, Stefan; Firle, Evelyn A.

2004-05-01

Medical imaging is nowadays much more than only providing data for diagnosis. It also links 'classical' diagnosis to modern forms of treatment such as image guided surgery. Those systems require the identification of organs, anatomical regions of the human body etc., i. e. the segmentation of structures from medical data sets. The algorithms used for these segmentation tasks strongly depend on the object to be segmented. One structure which plays an important role in surgery planning are vessels that are found everywhere in the human body. Several approaches for their extraction already exist. However, there is no general one which is suitable for all types of data or all sorts of vascular structures. This work presents a new algorithm for the segmentation of vessels. It can be classified as a skeleton-based approach working on 3D data sets, and has been designed for a reliable segmentation of coronary arteries. The algorithm is a semi-automatic extraction technique requiring the definition of the start and end the point of the (centerline) path to be found. A first estimation of the vessel's centerline is calculated and then corrected iteratively by detecting the vessel's border perpendicular to the centerline. We used contrast enhanced CT data sets of the thorax for testing our approach. Coronary arteries have been extracted from the data sets using the 'corkscrew algorithm' presented in this work. The segmentation turned out to be robust even if moderate breathing artifacts were present in the data sets.

Quantification of Processing Effects on Filament Wound Pressure Vessels

NASA Technical Reports Server (NTRS)

Aiello, Robert A.; Chamis, Christos C.

1999-01-01

A computational simulation procedure is described which is designed specifically for the modeling and analysis of filament wound pressure vessels. Cylindrical vessels with spherical or elliptical end caps can be generated automatically. End caps other than spherical or elliptical may be modeled by varying circular sections along the x-axis according to the C C! end cap shape. The finite element model generated is composed of plate type quadrilateral shell elements on the entire vessel surface. This computational procedure can also be sued to generate grid, connectivity and material cards (bulk data) for component parts of a larger model. These bulk data are assigned to a user designated file for finite element structural/stress analysis of composite pressure vessels. The procedure accommodates filament would pressure vessels of all types of shells-of-revolution. It has provisions to readily evaluate initial stresses due to pretension in the winding filaments and residual stresses due to cure temperature.

Quantification of Processing Effects on Filament Wound Pressure Vessels. Revision

NASA Technical Reports Server (NTRS)

Aiello, Robert A.; Chamis, Christos C.

2002-01-01

A computational simulation procedure is described which is designed specifically for the modeling and analysis of filament wound pressure vessels. Cylindrical vessels with spherical or elliptical end caps can be generated automatically. End caps other than spherical or elliptical may be modeled by varying circular sections along the x-axis according to the end cap shape. The finite element model generated is composed of plate type quadrilateral shell elements on the entire vessel surface. This computational procedure can also be used to generate grid, connectivity and material cards (bulk data) for component parts of a larger model. These bulk data are assigned to a user designated file for finite element structural/stress analysis of composite pressure vessels. The procedure accommodates filament wound pressure vessels of all types of shells-of -revolution. It has provisions to readily evaluate initial stresses due to pretension in the winding filaments and residual stresses due to cure temperature.

Optical coherence tomography assessment of vessel wall degradation in aneurysmatic thoracic aortas

NASA Astrophysics Data System (ADS)

Real, Eusebio; Eguizabal, Alma; Pontón, Alejandro; Val-Bernal, J. Fernando; Mayorga, Marta; Revuelta, José M.; López-Higuera, José; Conde, Olga M.

2013-06-01

Optical coherence tomographic images of ascending thoracic human aortas from aneurysms exhibit disorders on the smooth muscle cell structure of the media layer of the aortic vessel as well as elastin degradation. Ex-vivo measurements of human samples provide results that correlate with pathologist diagnosis in aneurysmatic and control aortas. The observed disorders are studied as possible hallmarks for aneurysm diagnosis. To this end, the backscattering profile along the vessel thickness has been evaluated by fitting its decay against two different models, a third order polynomial fitting and an exponential fitting. The discontinuities present on the vessel wall on aneurysmatic aortas are slightly better identified with the exponential approach. Aneurysmatic aortic walls present uneven reflectivity decay when compared with healthy vessels. The fitting error has revealed as the most favorable indicator for aneurysm diagnosis as it provides a measure of how uniform is the decay along the vessel thickness.

Evaluation of Progressive Failure Analysis and Modeling of Impact Damage in Composite Pressure Vessels

NASA Technical Reports Server (NTRS)

Sanchez, Christopher M.

2011-01-01

NASA White Sands Test Facility (WSTF) is leading an evaluation effort in advanced destructive and nondestructive testing of composite pressure vessels and structures. WSTF is using progressive finite element analysis methods for test design and for confirmation of composite pressure vessel performance. Using composite finite element analysis models and failure theories tested in the World-Wide Failure Exercise, WSTF is able to estimate the static strength of composite pressure vessels. Additionally, test and evaluation on composites that have been impact damaged is in progress so that models can be developed to estimate damage tolerance and the degradation in static strength.

Torus-margo pits help conifers compete with angiosperms.

PubMed

Pittermann, Jarmila; Sperry, John S; Hacke, Uwe G; Wheeler, James K; Sikkema, Elzard H

2005-12-23

The unicellular conifer tracheid should have greater flow resistance per length (resistivity) than the multicellular angiosperm vessel, because its high-resistance end-walls are closer together. However, tracheids and vessels had comparable resistivities for the same diameter, despite tracheids being over 10 times shorter. End-wall pits of tracheids averaged 59 times lower flow resistance on an area basis than vessel pits, owing to the unique torus-margo structure of the conifer pit membrane. The evolution of this membrane was as hydraulically important as that of vessels. Without their specialized pits, conifers would have 38 times the flow resistance, making conifer-dominated ecosystems improbable in an angiosperm world.

Structural design, analysis, and code evaluation of an odd-shaped pressure vessel

NASA Astrophysics Data System (ADS)

Rezvani, M. A.; Ziada, H. H.

1992-12-01

An effort to design, analyze, and evaluate a rectangular pressure vessel is described. Normally pressure vessels are designed in circular or spherical shapes to prevent stress concentrations. In this case, because of operational limitations, the choice of vessels was limited to a rectangular pressure box with a removable cover plate. The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code is used as a guideline for pressure containments whose width or depth exceeds 15.24 cm (6.0 in.) and where pressures will exceed 103.4 KPa (15.0 lbf/in(sup 2)). This evaluation used Section 8 of this Code, hereafter referred to as the Code. The dimensions and working pressure of the subject vessel fall within the pressure vessel category of the Code. The Code design guidelines and rules do not directly apply to this vessel. Therefore, finite-element methodology was used to analyze the pressure vessel, and the Code then was used in qualifying the vessel to be stamped to the Code. Section 8, Division 1 of the Code was used for evaluation. This action was justified by selecting a material for which fatigue damage would not be a concern. The stress analysis results were then checked against the Code, and the thicknesses adjusted to satisfy Code requirements. Although not directly applicable, the Code design formulas for rectangular vessels were also considered and presented.

Interrelationship of Nondestructive Evaluation Methodologies Applied to Testing of Composite Overwrapped Pressure Vessels

NASA Technical Reports Server (NTRS)

Leifeste, Mark R.

2007-01-01

Composite Overwrapped Pressure Vessels (COPVs) are commonly used in spacecraft for containment of pressurized gases and fluids, incorporating strength and weight savings. The energy stored is capable of extensive spacecraft damage and personal injury in the event of sudden failure. These apparently simple structures, composed of a metallic media impermeable liner and fiber/resin composite overwrap are really complex structures with numerous material and structural phenomena interacting during pressurized use which requires multiple, interrelated monitoring methodologies to monitor and understand subtle changes critical to safe use. Testing of COPVs at NASA Johnson Space Center White Sands T est Facility (WSTF) has employed multiple in-situ, real-time nondestructive evaluation (NDE) methodologies as well as pre- and post-test comparative techniques to monitor changes in material and structural parameters during advanced pressurized testing. The use of NDE methodologies and their relationship to monitoring changes is discussed based on testing of real-world spacecraft COPVs. Lessons learned are used to present recommendations for use in testing, as well as a discussion of potential applications to vessel health monitoring in future applications.

Interactive Physical Simulation of Catheter Motion within Mayor Vessel Structures and Cavities for ASD/VSD Treatment

NASA Astrophysics Data System (ADS)

Becherer, Nico; Hesser, Jürgen; Kornmesser, Ulrike; Schranz, Dietmar; Männer, Reinhard

2007-03-01

Simulation systems are becoming increasingly essential in medical education. Hereby, capturing the physical behaviour of the real world requires a sophisticated modelling of instruments within the virtual environment. Most models currently used are not capable of user interactive simulations due to the computation of the complex underlying analytical equations. Alternatives are often based on simplifying mass-spring systems, being able to deliver high update rates that come at the cost of less realistic motion. In addition, most techniques are limited to narrow and tubular vessel structures or restrict shape alterations to two degrees of freedom, not allowing instrument deformations like torsion. In contrast, our approach combines high update rates with highly realistic motion and can in addition be used with respect to arbitrary structures like vessels or cavities (e.g. atrium, ventricle) without limiting the degrees of freedom. Based on energy minimization, bending energies and vessel structures are considered as linear elastic elements; energies are evaluated at regularly spaced points on the instrument, while the distance of the points is fixed, i.e. we simulate an articulated structure of joints with fixed connections between them. Arbitrary tissue structures are modeled through adaptive distance fields and are connected by nodes via an undirected graph system. The instrument points are linked to nodes by a system of rules. Energy minimization uses a Quasi Newton method without preconditioning and, hereby, gradients are estimated using a combination of analytical and numerical terms. Results show a high quality in motion simulation when compared to a phantom model. The approach is also robust and fast. Simulating an instrument with 100 joints runs at 100 Hz on a 3 GHz PC.

Vessel with filter and method of use

DOEpatents

Morrell, Jonathan S.; Ripley, Edward B.; Cecala, David M.

2008-01-29

Chemical processing apparatuses which incorporate a process vessel, such as a crucible or retort, and which include a gas separation or filtration system. Various embodiments incorporate such features as loose filtration material, semi-rigid filtration material, and structured filtration material. The vessel may include material that is a microwave susceptor. Filtration media may be selected so that if it inadvertently mixes with the chemical process or the reaction products of such process, it would not adversely affect the results of the chemical process.

Niobium Application, Metallurgy and Global Trends in Pressure Vessel Steels

NASA Astrophysics Data System (ADS)

Jansto, Steven G.

Niobium-containing high strength steel materials have been developed for a variety of pressure vessel applications. Through the application of these Nb-bearing steels in demanding applications, the designer and end user experience improved toughness at low temperature, excellent fatigue resistance and fracture toughness and excellent weldability. These enhancements provide structural engineers the opportunity to further improve the pressure vessel design and performance. The Nb-microalloy alloy designs also result in reduced operational production cost at the steel operation, thereby embracing the value-added attribute Nb provides to both the producer and the end user throughout the supply chain. For example, through the adoption of these Nb-containing structural materials, several design-manufacturing companies are considering improved designs which offer improved manufacturability, lower overall cost and better life cycle performance.

Nitric oxide transport in blood: a third gas in the respiratory cycle.

PubMed

Doctor, Allan; Stamler, Jonathan S

2011-01-01

The trapping, processing, and delivery of nitric oxide (NO) bioactivity by red blood cells (RBCs) have emerged as a conserved mechanism through which regional blood flow is linked to biochemical cues of perfusion sufficiency. We present here an expanded paradigm for the human respiratory cycle based on the coordinated transport of three gases: NO, O₂, and CO₂. By linking O₂ and NO flux, RBCs couple vessel caliber (and thus blood flow) to O₂ availability in the lung and to O₂ need in the periphery. The elements required for regulated O₂-based signal transduction via controlled NO processing within RBCs are presented herein, including S-nitrosothiol (SNO) synthesis by hemoglobin and O₂-regulated delivery of NO bioactivity (capture, activation, and delivery of NO groups at sites remote from NO synthesis by NO synthase). The role of NO transport in the respiratory cycle at molecular, microcirculatory, and system levels is reviewed. We elucidate the mechanism through which regulated NO transport in blood supports O₂ homeostasis, not only through adaptive regulation of regional systemic blood flow but also by optimizing ventilation-perfusion matching in the lung. Furthermore, we discuss the role of NO transport in the central control of breathing and in baroreceptor control of blood pressure, which subserve O₂ supply to tissue. Additionally, malfunctions of this transport and signaling system that are implicated in a wide array of human pathophysiologies are described. Understanding the (dys)function of NO processing in blood is a prerequisite for the development of novel therapies that target the vasoactive capacities of RBCs. © 2011 American Physiological Society.

Blood-brain barrier disruption and vascular damage induced by ultrasound bursts combined with microbubbles can be influenced by choice of anesthesia protocol

PubMed Central

McDannold, Nathan; Zhang, Yongzhi; Vykhodtseva, Natalia

2011-01-01

Numerous animal studies have demonstrated that ultrasound bursts combined with a microbubble-based ultrasound contrast agent can temporarily disrupt the blood-brain barrier (BBB) with little or no other apparent effects to the brain. As the BBB is a primary limitation to the use of most drugs in the brain, this method could enable a noninvasive means for targeted drug delivery in the brain. This work investigated whether BBB disruption and vessel damage when overexposure occurs can be influenced by choice of anesthesia protocol, which have different vasoactive effects. Four locations were sonicated transcranially in each brain of 16 rats using an unfocused 532 kHz piston transducer. Burst sonications (10 ms bursts applied at 1 Hz for 60 s) were combined with intravenous Definity (10 μl/kg) injections. BBB disruption was evaluated using contrast-enhanced MRI. Half of the animals were anesthetized with i.p. ketamine and xylazine, and the other half with inhaled isoflurane and oxygen. Over the range of exposure levels tested, MRI contrast enhancement was significantly higher (P<0.05) for animals anesthetized with ketamine/xylazine. Furthermore, the threshold for extensive erythrocyte extravasation was lower with ketamine/xylazine. These results suggest that BBB disruption and/or vascular damage can be affected by vascular or other factors that are influenced by different anesthesia protocol. These experiments may also have been influenced by the recently reported findings that the circulation time for perfluorocarbon microbubbles is substantially reduced when oxygen is used as the carrier gas. PMID:21645965

Electrophysiological, vasoactive, and gastromodulatory effects of stevia in healthy Wistar rats.

PubMed

Yesmine, Saquiba; Connolly, Kylie; Hill, Nicholas; Coulson, Fiona R; Fenning, Andrew S

2013-07-01

Antihypertensive and antidiabetic effects of stevia, Stevia rebaudiana (Asteraceae), have been demonstrated in several human and animal models. The current study aims to define stevia's role in modifying the electrophysiological and mechanical properties of cardiomyocytes, blood vessels, and gastrointestinal smooth muscle. Tissues from thoracic aorta, mesenteric arteries, ileum, and left ventricular papillary muscles were excised from 8-week-old healthy Wistar rats. The effects of stevia (1 × 10-9 M to 1 × 10-4 M) were measured on these tissues. Stevia's effects in the presence of verapamil, 4-AP, and L-NAME were also assessed. In cardiomyocytes, stevia attenuated the force of contraction, decreased the average peak amplitude, and shortened the repolarisation phase of action potential - repolarisation phase of action potential20 by 25 %, repolarisation phase of action potential50 by 34 %, and repolarisation phase of action potential90 by 36 %. Stevia caused relaxation of aortic tissues which was significantly potentiated in the presence of verapamil. In mesenteric arteries, incubation with L-NAME failed to block stevia-induced relaxation indicating the mechanism of action may not be fully via nitric oxide-dependent pathways. Stevia concentration-dependently reduced electrical field stimulated and carbachol-induced contractions in the isolated ileum. This study is the first to show the effectiveness of stevia in reducing cardiac action potential duration at 20 %, 50 %, and 90 % of repolarisation. Stevia also showed beneficial modulatory effects on cardiovascular and gastrointestinal tissues via calcium channel antagonism, activation of the M2 muscarinic receptor function, and enhanced nitric oxide release. Georg Thieme Verlag KG Stuttgart · New York.

Laser Doppler flowmetry for measurement of laminar capillary blood flow in the horse

NASA Astrophysics Data System (ADS)

Adair, Henry S., III

1998-07-01

Current methods for in vivo evaluation of digital hemodynamics in the horse include angiography, scintigraphy, Doppler ultrasound, electromagnetic flow and isolated extracorporeal pump perfused digit preparations. These techniques are either non-quantifiable, do not allow for continuous measurement, require destruction of the horse orare invasive, inducing non- physiologic variables. In vitro techniques have also been reported for the evaluation of the effects of vasoactive agents on the digital vessels. The in vitro techniques are non-physiologic and have evaluated the vasculature proximal to the coronary band. Lastly, many of these techniques require general anesthesia or euthanasia of the animal. Laser Doppler flowmetry is a non-invasive, continuous measure of capillary blood flow. Laser Doppler flowmetry has been used to measure capillary blood flow in many tissues. The principle of this method is to measure the Doppler shift, that is, the frequency change that light undergoes when reflected by moving objects, such as red blood cells. Laser Doppler flowmetry records a continuous measurement of the red cell motion in the outer layer of the tissue under study, with little or no influence on physiologic blood flow. This output value constitutes the flux of red cells and is reported as capillary perfusion units. No direct information concerning oxygen, nutrient or waste metabolite exchange in the surrounding tissue is obtained. The relationship between the flowmeter output signal and the flux of red blood cells is linear. The principles of laser Doppler flowmetry will be discussed and the technique for laminar capillary blood flow measurements will be presented.

Recent insights and therapeutic perspectives of angiotensin-(1-9) in the cardiovascular system.

PubMed

Ocaranza, Maria Paz; Michea, Luis; Chiong, Mario; Lagos, Carlos F; Lavandero, Sergio; Jalil, Jorge E

2014-11-01

Chronic RAS (renin-angiotensin system) activation by both AngII (angiotensin II) and aldosterone leads to hypertension and perpetuates a cascade of pro-hypertrophic, pro-inflammatory, pro-thrombotic and atherogenic effects associated with cardiovascular damage. In 2000, a new pathway consisting of ACE2 (angiotensin-converting enzyme2), Ang-(1-9) [angiotensin-(1-9)], Ang-(1-7) [angiotensin-(1-7)] and the Mas receptor was discovered. Activation of this novel pathway stimulates vasodilation, anti-hypertrophy and anti-hyperplasia. For some time, studies have focused mainly on ACE2, Ang-(1-7) and the Mas receptor, and their biological properties that counterbalance the ACE/AngII/AT1R (angiotensin type 1 receptor) axis. No previous information about Ang-(1-9) suggested that this peptide had biological properties. However, recent data suggest that Ang-(1-9) protects the heart and blood vessels (and possibly the kidney) from adverse cardiovascular remodelling in patients with hypertension and/or heart failure. These beneficial effects are not modified by the Mas receptor antagonist A779 [an Ang-(1-7) receptor blocker], but they are abolished by the AT2R (angiotensin type 2 receptor) antagonist PD123319. Current information suggests that the beneficial effects of Ang-(1-9) are mediated via the AT2R. In the present review, we summarize the biological effects of the novel vasoactive peptide Ang-(1-9), providing new evidence of its cardiovascular-protective activity. We also discuss the potential mechanism by which this peptide prevents and ameliorates the cardiovascular damage induced by RAS activation.

Remodeling of the skeletal muscle microcirculation increases resistance to perfusion in obese Zucker rats.

PubMed

Frisbee, Jefferson C

2003-07-01

Whereas previous studies have demonstrated that the development of syndrome X in obese Zucker rats (OZR) is associated with impaired arteriolar reactivity to vasoactive stimuli, additional results from these studies indicate that the passive diameter of skeletal muscle arterioles is reduced in OZR versus lean Zucker rats (LZR). On the basis of these prior observations, the present study evaluated structural alterations to the skeletal muscle microcirculation as potential contributors to an elevated vascular resistance. Isolated skeletal muscle resistance arterioles exhibited a reduced passive diameter at all levels of intralumenal pressure and a left-shifted stress-strain curve in OZR versus LZR, indicative of structural remodeling of individual arterioles. Histological analyses using Griffonia simplicifolia I lectin-stained sections of skeletal muscle demonstrated reduced microvessel density (rarefaction) in OZR versus LZR, suggesting remodeling of entire microvascular networks. Finally, under maximally dilated conditions, constant flow-perfused skeletal muscle of OZR exhibited significant elevations in perfusion pressure versus LZR, indicative of an increased resistance to perfusion within the microcirculation. These data suggest that developing structural alterations to the skeletal muscle microcirculation in OZR result in elevated vascular resistance, which may, acting in concert with impaired arteriolar reactivity, contribute to blunted active hyperemic responses and compromised performance of in situ skeletal muscle with elevated metabolic demand.

Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins.

PubMed

González-Guerra, José Luis; Castilla-Cortazar, Inma; Aguirre, Gabriel A; Muñoz, Úrsula; Martín-Estal, Irene; Ávila-Gallego, Elena; Granado, Miriam; Puche, Juan E; García-Villalón, Ángel Luis

2017-01-01

Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R). In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides); carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions.

Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins

PubMed Central

Aguirre, Gabriel A.; Muñoz, Úrsula; Martín-Estal, Irene; Ávila-Gallego, Elena; Granado, Miriam; Puche, Juan E.; García-Villalón, Ángel Luis

2017-01-01

Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R). In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides); carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions. PMID:28806738

Augmentation of ferulic acid-induced vasorelaxation with aging and its structure importance in thoracic aorta of spontaneously hypertensive rats.

PubMed

Fukuda, Toshihiko; Kuroda, Takahiro; Kono, Miki; Hyoguchi, Mai; Tanaka, Mitsuru; Matsui, Toshiro

2015-10-01

Aging deteriorates vascular functions such as vascular reactivity and stiffness. Thus far, various reports suggest that bioactive compounds can improve vascular functions. However, few age-related studies of natural bioactive compounds are available. The present study attempted to evaluate age-related vasorelaxation of bioactive cinnamic acids, caffeic acid, and ferulic acid using aged rat thoracic aorta. Vasorelaxation was evaluated in thoracic aorta from both 8, 18, and 40 weeks old Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) respectively. The result indicated that caffeic acid possessed the vasorelaxation regardless of aging in WKY and SHR. Moreover, the vasorelaxation of ferulic acid enhanced with aging in SHR. The vasorelaxation behavior was acted in an endothelium-independent manner. To access structure importance of enhanced vasorelaxation, analogues of ferulic acid were tested. In 40 weeks old SHR, 3,4-dimethoxycinnamic acid and coniferyl alcohol exhibited equivalent vasorelaxation activity with ferulic acid, providing the structural importance of methoxy-modified 3-position on the phenyl ring and 2-propenoic moiety. These results firstly demonstrated that enhanced vasorelaxation of ferulic acid with aging and 3,4-dimethoxycinnamic acid and coniferyl alcohol, along with ferulic acid, might exhibit the therapeutic potential of vasoactive power with aging.

46 CFR 169.234 - Integral fuel oil tank examinations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... operator of the vessel shall have the tanks cleaned out and gas freed as necessary to permit internal... an examination of the fuel tanks of each vessel during an internal structural examination at... and internally examined if the marine inspector is able to determine by external examination that the...

46 CFR 91.40-1 - Definitions relating to hull examinations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Definitions relating to hull examinations. 91.40-1... VESSELS INSPECTION AND CERTIFICATION Drydocking § 91.40-1 Definitions relating to hull examinations. As...-hull fittings. (b) Internal structural examination means an examination of the vessel while afloat or...

Automation process for morphometric analysis of volumetric CT data from pulmonary vasculature in rats.

PubMed

Shingrani, Rahul; Krenz, Gary; Molthen, Robert

2010-01-01

With advances in medical imaging scanners, it has become commonplace to generate large multidimensional datasets. These datasets require tools for a rapid, thorough analysis. To address this need, we have developed an automated algorithm for morphometric analysis incorporating A Visualization Workshop computational and image processing libraries for three-dimensional segmentation, vascular tree generation and structural hierarchical ordering with a two-stage numeric optimization procedure for estimating vessel diameters. We combine this new technique with our mathematical models of pulmonary vascular morphology to quantify structural and functional attributes of lung arterial trees. Our physiological studies require repeated measurements of vascular structure to determine differences in vessel biomechanical properties between animal models of pulmonary disease. Automation provides many advantages including significantly improved speed and minimized operator interaction and biasing. The results are validated by comparison with previously published rat pulmonary arterial micro-CT data analysis techniques, in which vessels were manually mapped and measured using intense operator intervention. Published by Elsevier Ireland Ltd.

Transplantations and Cloning of an Immortal Cell Line from Rat SCN

DTIC Science & Technology

1994-05-31

of SCN peptides in colonies was examined using rabbit polyclonal antisera against arginine vasopressin (AVP; Arnel Products), gastrin releasing ...examined for expression of arginine vasopressin (AVP), gastrin releasing peptide (GRP), somatostatin (SMT) and vasoactive intestinal polypeptide (VIP...neuronal markers and peptides found within SCN neurons in situ. Concordant with immunostaining data, content, release and mRNA expression of SCN

Effects Of Exercise During Prolonged Bed Rest

NASA Technical Reports Server (NTRS)

Arnaud, S.; Berry, P; Cohen, M.; Danelis, J.; Deroshia, C.; Greenleaf, J.; Harris, B.; Keil, L.; Bernauer, E.; Bond, M.;

The Impact of Vasoactive Drugs on Oxygenation and Tissue Perfusion

DTIC Science & Technology

1992-01-01

blood. Diffusion defects are seen in patients with pulmonary fibrosis and adult respiratory distress syndrome among others (Von Rueden, 1989; Reischman...increased oxyhemoglobin affinity include alkalosis , hypocarbia, hypothermia, hypophosphatemia and decreased levels of 2,3 - DPG (Mims, 1989; Von Rueden...which cause degranulation of mast cells, basophils and neutrophils. Neutrophils are responsible for respiratory bursts. These bursts are actually

Efficacies of Papaverine and Sildenafil in the Treatment of Erectile Dysfunction in Early-Stage Paraplegic Men

ERIC Educational Resources Information Center

Yildiz, Necmettin; Gokkaya, Nilufer Kutay Ordu; Koseoglu, Fusun; Gokkaya, Serkan; Comert, Didem

2011-01-01

The aim of the study was to determine which vasoactive agent was more efficacious for erectile dysfunction (ED), intracavernosal papaverine or oral sildenafil, in paraplegic men within the first year after injury by using a penile color Doppler ultrasound as a quantitative imaging method and to determine the association between responses to these…

Validation of spontaneous assessment of baroreceptor reflex sensitivity and its relation to heart rate variability in the ovine fetus pre- and near-term.

PubMed

Frasch, Martin G; Müller, Thomas; Szynkaruk, Mark; Schwab, Matthias

2009-09-01

Assessment of baroreceptor reflex sensitivity (BRS) in the ovine fetus provides insight into autonomic cardiovascular regulation. Currently, assessment of BRS relies on vasoactive drugs, but this approach is limited by feasibility issues and by the nonphysiologic nature of the stimulus. Thus we aimed to validate the method of spontaneous BRS assessment against the reference method of using vasoactive drugs in preterm (0.76 gestation, n = 16) and near-term (0.86 gestation, n = 16) chronically instrumented ovine fetuses. The BRS measures derived from the spontaneous and reference methods correlated at both gestational ages (R = 0.67 +/- 0.03). The sequence method of spontaneous BRS measures also correlated both to the root mean square of standard deviations (RMSSD), which is a measure of fetal heart rate variability reflecting vagal modulation (R = 0.69 +/- 0.03), and to fetal body weight (R = 0.65 +/- 0.03), which is a surrogate for growth trajectory of each fetus. The methodology presented may aid in developing new models to study BRS and cardiovascular control in ovine fetus in the last trimester of pregnancy.

[The Contribution of Vascular Capacity and Blood Volume to Maintain Stable Blood Circulation during General Anesthesia].

PubMed

Shigemi, Kenji

2016-05-01

To maintain proper cardiac preload is one of the most effective procedures for the systemic circulation remaining stable. In particular, the balance between vascular capacity and total blood volume must be maintained within appropriate range by the administration of fluids, blood and/or vasoactive drugs with mean circulatory filling pressure (Pmcf), central venous pressure (CVP) or stroke volume variation (SVV). End-diastolic left ventricular volume (Ved) is theoretically the best index of cardiac preload; however, without transesophageal echocardbalanceiogram we cannot directly monitor Ved during anesthesia. The infused fluid volume remaining in intravascular space, the vascular capacity controlled by autonomic nervous system and/or vasoactive agents, and the unstressed blood volume properly mobilized to excess blood volume are the crucial factors to maintain cardiac output The knowledge of vascular physiology contribute the decision making to manipulate such factors to control blood circulation during general anesthesia. For example, CVP is usually maintained in the narrow range and seems to be stable; however, it must be changed just after the circulatory disturbances, such as acute bleeding, blood transfusion, and fluid infusion, and followed by gradual returning to initial value, because of the solid mechanism to preserve cardiac output

Pancreatic polypeptide controls energy homeostasis via Npy6r signaling in the suprachiasmatic nucleus in mice.

PubMed

Yulyaningsih, Ernie; Loh, Kim; Lin, Shu; Lau, Jackie; Zhang, Lei; Shi, Yanchuan; Berning, Britt A; Enriquez, Ronaldo; Driessler, Frank; Macia, Laurence; Khor, Ee Cheng; Qi, Yue; Baldock, Paul; Sainsbury, Amanda; Herzog, Herbert

2014-01-07

Y-receptors control energy homeostasis, but the role of Npy6 receptors (Npy6r) is largely unknown. Young Npy6r-deficient (Npy6r(-/-)) mice have reduced body weight, lean mass, and adiposity, while older and high-fat-fed Npy6r(-/-) mice have low lean mass with increased adiposity. Npy6r(-/-) mice showed reduced hypothalamic growth hormone releasing hormone (Ghrh) expression and serum insulin-like growth factor-1 (IGF-1) levels relative to WT. This is likely due to impaired vasoactive intestinal peptide (VIP) signaling in the suprachiasmatic nucleus (SCN), where we found Npy6r coexpressed in VIP neurons. Peripheral administration of pancreatic polypeptide (PP) increased Fos expression in the SCN, increased energy expenditure, and reduced food intake in WT, but not Npy6r(-/-), mice. Moreover, intraperitoneal (i.p.) PP injection increased hypothalamic Ghrh mRNA expression and serum IGF-1 levels in WT, but not Npy6r(-/-), mice, an effect blocked by intracerebroventricular (i.c.v.) Vasoactive Intestinal Peptide (VPAC) receptors antagonism. Thus, PP-initiated signaling through Npy6r in VIP neurons regulates the growth hormone axis and body composition. Copyright © 2014 Elsevier Inc. All rights reserved.

Immunohistochemical study of vasoactive intestinal peptide (VIP) enteric neurons in diabetic rats supplemented with L-glutamine.

PubMed

Alves, Eder Paulo Belato; Alves, Angela Maria Pereira; Pereira, Renata Virginia Fernandes; de Miranda Neto, Marcílio Hubner; Zanoni, Jacqueline Nelisis

2010-02-01

The purpose of this work was to study the area of the varicosities of nerve fibers of myenteric neurons immunoreactive to vasoactive intestinal peptide (VIP-IR) and of the cell bodies of VIP-IR submucosal neurons of the jejunum of diabetic rats supplemented with 2% L-glutamine. Twenty male rats were divided into the following groups: normoglycemic (N), normoglycemic supplemented with L-glutamine (NG), diabetic (D) and diabetic supplemented with L-glutamine (DG). Whole-mounts of the muscle tunica and the submucosal layer were subjected to the immunohistochemical technique for neurotransmitter VIP identification. Morphometric analyses were carried out in 500 VIP-IR cell bodies of submucosal neurons and 2000 VIP-IR varicosities from each group. L-Glutamine supplementation to the normoglycemic animals caused an increase in the areas of the cell bodies (8.49%) and varicosities (21.3%) relative to the controls (P < 0.05). On the other hand, there was a decrease in the areas of the cell bodies (4.55%) and varicosities (28.9%) of group DG compared to those of group D (P < 0.05). It is concluded that L-glutamine supplementation was positive both to normoglycemic and diabetic animals.

Light-dark cycle memory in the mammalian suprachiasmatic nucleus.

PubMed

Ospeck, Mark C; Coffey, Ben; Freeman, Dave

2009-09-16

The mammalian circadian oscillator, or suprachiasmatic nucleus (SCN), contains several thousand clock neurons in its ventrolateral division, many of which are spontaneous oscillators with period lengths that range from 22 to 28 h. In complete darkness, this network synchronizes through the exchange of action potentials that release vasoactive intestinal polypeptide, striking a compromise, free-running period close to 24 h long. We entrained Siberian hamsters to various light-dark cycles and then tracked their activity into constant darkness to show that they retain a memory of the previous light-dark cycle before returning to their own free-running period. Employing Leloup-Goldbeter mammalian clock neurons we model the ventrolateral SCN network and show that light acting weakly upon a strongly rhythmic vasoactive intestinal polypeptide oscillation can explain the observed light-dark cycle memory. In addition, light is known to initiate a mitogen-activated protein kinase signaling cascade that induces transcription of both per and mkp1 phosphatase. We show that the ensuing phosphatase-kinase interaction can account for the dead zone in the mammalian phase response curve and hypothesize that the SCN behaves like a lock-in amplifier to entrain to the light edges of the circadian day.

Idiopathic Non-Cirrhotic Intrahepatic Portal Hypertension (NCIPH)—Newer Insights into Pathogenesis and Emerging Newer Treatment Options

PubMed Central

Goel, Ashish; Elias, Joshua E.; Eapen, Chundamannil E.; Ramakrishna, Banumathi; Elias, Elwyn

2014-01-01

Chronic microangiopathy of portal venules results in idiopathic non-cirrhotic intrahepatic portal hypertension (NCIPH). Recent data suggest a role for vasoactive factors of portal venous origin in the pathogenesis of this ‘pure’ vasculopathy of the liver. Enteropathies (often silent), are an important ‘driver’ of this disease. NCIPH is under-recognized and often mis-labeled as cryptogenic cirrhosis. Liver biopsy is needed to prove the diagnosis of NCIPH. In these patients, with advancing disease and increased porto-systemic shunting, the portal venous vasoactive factors bypass the liver filter and contribute to the development of pulmonary vascular endothelial disorders—porto-pulmonary hypertension and hepato-pulmonary syndrome as well as mesangiocapillary glomerulonephritis. Prognosis in NCIPH patients is determined by presence, recognition and management of associated disorders. With better understanding of the pathogenesis of NCIPH, newer treatment options are being explored. Imbalance in ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13): vWF (von-Willebrand factor) ratio is documented in NCIPH patients and may have a pathogenic role. Therapeutic interventions to correct this imbalance may prove to be important in the management of NCIPH. PMID:25755567

Characterization of autoantibodies to vasoactive intestinal peptide in asthma.

PubMed

Paul, S; Said, S I; Thompson, A B; Volle, D J; Agrawal, D K; Foda, H; de la Rocha, S

1989-07-01

Vasoactive intestinal peptide (VIP) is a potent relaxant of the airway smooth muscle. In this study, VIP-binding autoantibodies were observed in the plasma of 18% asthma patients and 16% healthy subjects. Immunoprecipitation studies and chromatography on DEAE-cellulose and immobilized protein G indicated that the plasma VIP-binding activity was largely due to IgG antibodies. Saturation analysis of VIP binding by the plasmas suggested the presence of one or two classes of autoantibodies, distinguished by their apparent equilibrium affinity constants (Ka). The autoantibodies from asthma patients exhibited a larger VIP-binding affinity compared to those from healthy subjects (Ka 7.8 x 10(9) M-1 and 0.13 x 10(9) M-1, respectively; P less than 0.005). The antibodies were specific for VIP, judged by their poor reaction with peptides bearing partial sequence homology with VIP (peptide histidine isoleucine, growth hormone releasing factor and secretin). IgG prepared from the plasma of an antibody-positive asthma patient inhibited the saturable binding of 125I-VIP by receptors in guinea pig lung membranes (by 39-59%; P less than 0.001). These observations are consistent with a role for the VIP autoantibodies in the airway hyperresponsiveness of asthma.

Regulatory peptide distribution in separated layers of the human jejunum.

PubMed

Ferri, G L; Adrian, T E; Soimero, L; McGregor, G P; Ghatei, M A; Morreale, R A; Rebecchi, L; Tonelli, L; Polak, J M; Bloom, S R

1987-01-01

The distribution of regulatory peptides was studied in the separated epithelium, lamina propria, submucosa and muscularis externa of the human jejunum. Gastrin, secretin, gastric inhibitory polypeptide, enteroglucagon and neurotensin immunoreactivity were almost confined to the endocrine cell-containing mucosal epithelium (greater than 98% of the total content), only minor amounts of motilin being detected in non-epithelial layers (3.6 +/- 0.7%, mean +/- SEM, n = 7). Conversely, vasoactive intestinal polypeptide, substance P and mammalian bombesin were virtually limited to non-epithelial layers (greater than 99%). Only somatostatin was found in all layers (44 +/- 6.7% in the epithelium, 34 +/- 5.2% in the lamina propria, 13 +/- 2.9% in the submucosa, and 7.9 +/- 2.8% in the muscularis). Substance P was found in higher concentrations in the mucosa, compared to submucosa and muscle (56 +/- 10, 30 +/- 4.0 and 29 +/- 4.0 pmol/g, respectively), while vasoactive intestinal polypeptide was more abundant in the muscle (411 +/- 52 pmol/g) compared to mucosa and submucosa (228 +/- 64 and 219 +/- 31 pmol/g, respectively). Only low levels of mammalian bombesin were measured, mainly in the muscle (6.9 +/- 1.5 pmol/g, or 89 +/- 3.6% of total content).

The interaction of vasoactive substances during exercise modulates platelet aggregation in hypertension and coronary artery disease

PubMed Central

Petidis, Konstantinos; Douma, Stella; Doumas, Michael; Basagiannis, Ilias; Vogiatzis, Konstantinos; Zamboulis, Chrysanthos

2008-01-01

Background Acute vigorous exercise, associated with increased release of plasma catecholamines, transiently increases the risk of primary cardiac arrest. We tested the effect of acute submaximal exercise on vasoactive substances and their combined result on platelet function. Methods Healthy volunteers, hypertensive patients and patients with coronary artery disease (CAD) performed a modified treadmill exercise test. We determined plasma catecholamines, thromboxane A2, prostacyclin, endothelin-1 and platelet aggregation induced by adenosine diphosphate (ADP) and collagen at rest and during exercise. Results Our results during exercise showed a) platelet activation (increased thromboxane B2, TXB2), b) increased prostacyclin release from endothelium and c) decreased platelet aggregation in all groups, significantly more in healthy volunteers than in patients with CAD (with hypertensives lying in between these two groups). Conclusion Despite the pronounced activation of Sympathetic Nervous System (SNS) and increased TXB2 levels during acute exercise platelet aggregation decreases, possibly to counterbalance the prothrombotic state. Since this effect seems to be mediated by the normal endothelium (through prostacyclin and nitric oxide), in conditions characterized by endothelial dysfunction (hypertension, CAD) reduced platelet aggregation is attenuated, thus posing such patients in increased risk for thrombotic complications. PMID:18505546

Endothelin-1 Mediates Brain Microvascular Dysfunction Leading to Long-Term Cognitive Impairment in a Model of Experimental Cerebral Malaria

PubMed Central

Freeman, Brandi D.; Martins, Yuri C.; Akide-Ndunge, Oscar B.; Bruno, Fernando P.; Wang, Hua; Tanowitz, Herbert B.; Spray, David C.; Desruisseaux, Mahalia S.

2016-01-01

Plasmodium falciparum infection causes a wide spectrum of diseases, including cerebral malaria, a potentially life-threatening encephalopathy. Vasculopathy is thought to contribute to cerebral malaria pathogenesis. The vasoactive compound endothelin-1, a key participant in many inflammatory processes, likely mediates vascular and cognitive dysfunctions in cerebral malaria. We previously demonstrated that C57BL6 mice infected with P. berghei ANKA, our fatal experimental cerebral malaria model, sustained memory loss. Herein, we demonstrate that an endothelin type A receptor (ETA) antagonist prevented experimental cerebral malaria-induced neurocognitive impairments and improved survival. ETA antagonism prevented blood-brain barrier disruption and cerebral vasoconstriction during experimental cerebral malaria, and reduced brain endothelial activation, diminishing brain microvascular congestion. Furthermore, exogenous endothelin-1 administration to P. berghei NK65-infected mice, a model generally regarded as a non-cerebral malaria negative control for P. berghei ANKA infection, led to experimental cerebral malaria-like memory deficits. Our data indicate that endothelin-1 is critical in the development of cerebrovascular and cognitive impairments with experimental cerebral malaria. This vasoactive peptide may thus serve as a potential target for adjunctive therapy in the management of cerebral malaria. PMID:27031954

Cryogenically formed prestressed composite fiber-metal structures for O2/N2 high pressure gas tanks.

NASA Technical Reports Server (NTRS)

Gleich, D.

1971-01-01

Demonstration of high-structural-performance ARDEFORM cryoformed 301 stainless-steel glass-fiber-reinforced (GFR) vessels by room temperature tests of 13 1/2-in. diam spheres. Tests verified that the structural performance of ARDEFORM spherical GFR vessels not only exceeded that of all metal construction, but also bettered previous GFR experimental results by 50%. Achievement of essentially the full strength of fiberglass in a spherical wrap pattern was again verified. Significant weight advantages for this construction are projected for O2/N2 high-pressure gas tanks for Space Shuttle environmental control/life support system missions.

Robust approach to ocular fundus image analysis

NASA Astrophysics Data System (ADS)

Tascini, Guido; Passerini, Giorgio; Puliti, Paolo; Zingaretti, Primo

1993-07-01

The analysis of morphological and structural modifications of retinal blood vessels plays an important role both to establish the presence of some systemic diseases as hypertension and diabetes and to study their course. The paper describes a robust set of techniques developed to quantitatively evaluate morphometric aspects of the ocular fundus vascular and micro vascular network. They are defined: (1) the concept of 'Local Direction of a vessel' (LD); (2) a special form of edge detection, named Signed Edge Detection (SED), which uses LD to choose the convolution kernel in the edge detection process and is able to distinguish between the left or the right vessel edge; (3) an iterative tracking (IT) method. The developed techniques use intensively both LD and SED in: (a) the automatic detection of number, position and size of blood vessels departing from the optical papilla; (b) the tracking of body and edges of the vessels; (c) the recognition of vessel branches and crossings; (d) the extraction of a set of features as blood vessel length and average diameter, arteries and arterioles tortuosity, crossing position and angle between two vessels. The algorithms, implemented in C language, have an execution time depending on the complexity of the currently processed vascular network.

An approach to localize the retinal blood vessels using bit planes and centerline detection.

PubMed

Fraz, M M; Barman, S A; Remagnino, P; Hoppe, A; Basit, A; Uyyanonvara, B; Rudnicka, A R; Owen, C G

2012-11-01

The change in morphology, diameter, branching pattern or tortuosity of retinal blood vessels is an important indicator of various clinical disorders of the eye and the body. This paper reports an automated method for segmentation of blood vessels in retinal images. A unique combination of techniques for vessel centerlines detection and morphological bit plane slicing is presented to extract the blood vessel tree from the retinal images. The centerlines are extracted by using the first order derivative of a Gaussian filter in four orientations and then evaluation of derivative signs and average derivative values is performed. Mathematical morphology has emerged as a proficient technique for quantifying the blood vessels in the retina. The shape and orientation map of blood vessels is obtained by applying a multidirectional morphological top-hat operator with a linear structuring element followed by bit plane slicing of the vessel enhanced grayscale image. The centerlines are combined with these maps to obtain the segmented vessel tree. The methodology is tested on three publicly available databases DRIVE, STARE and MESSIDOR. The results demonstrate that the performance of the proposed algorithm is comparable with state of the art techniques in terms of accuracy, sensitivity and specificity. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

An Active Contour Model Based on Adaptive Threshold for Extraction of Cerebral Vascular Structures.

PubMed

Wang, Jiaxin; Zhao, Shifeng; Liu, Zifeng; Tian, Yun; Duan, Fuqing; Pan, Yutong

2016-01-01

Cerebral vessel segmentation is essential and helpful for the clinical diagnosis and the related research. However, automatic segmentation of brain vessels remains challenging because of the variable vessel shape and high complex of vessel geometry. This study proposes a new active contour model (ACM) implemented by the level-set method for segmenting vessels from TOF-MRA data. The energy function of the new model, combining both region intensity and boundary information, is composed of two region terms, one boundary term and one penalty term. The global threshold representing the lower gray boundary of the target object by maximum intensity projection (MIP) is defined in the first-region term, and it is used to guide the segmentation of the thick vessels. In the second term, a dynamic intensity threshold is employed to extract the tiny vessels. The boundary term is used to drive the contours to evolve towards the boundaries with high gradients. The penalty term is used to avoid reinitialization of the level-set function. Experimental results on 10 clinical brain data sets demonstrate that our method is not only able to achieve better Dice Similarity Coefficient than the global threshold based method and localized hybrid level-set method but also able to extract whole cerebral vessel trees, including the thin vessels.

Aseismic safety analysis of a prestressed concrete containment vessel for CPR1000 nuclear power plant

NASA Astrophysics Data System (ADS)

Yi, Ping; Wang, Qingkang; Kong, Xianjing

2017-01-01

The containment vessel of a nuclear power plant is the last barrier to prevent nuclear reactor radiation. Aseismic safety analysis is the key to appropriate containment vessel design. A prestressed concrete containment vessel (PCCV) model with a semi-infinite elastic foundation and practical arrangement of tendons has been established to analyze the aseismic ability of the CPR1000 PCCV structure under seismic loads and internal pressure. A method to model the prestressing tendon and its interaction with concrete was proposed and the axial force of the prestressing tendons showed that the simulation was reasonable and accurate. The numerical results show that for the concrete structure, the location of the cylinder wall bottom around the equipment hatch and near the ring beam are critical locations with large principal stress. The concrete cracks occurred at the bottom of the PCCV cylinder wall under the peak earthquake motion of 0.50 g, however the PCCV was still basically in an elastic state. Furthermore, the concrete cracks occurred around the equipment hatch under the design internal pressure of 0.4MPa, but the steel liner was still in the elastic stage and its leak-proof function soundness was verified. The results provide the basis for analysis and design of containment vessels.

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.

A novel method for identifying a graph-based representation of 3-D microvascular networks from fluorescence microscopy image stacks.

PubMed

Almasi, Sepideh; Xu, Xiaoyin; Ben-Zvi, Ayal; Lacoste, Baptiste; Gu, Chenghua; Miller, Eric L

2015-02-01

A novel approach to determine the global topological structure of a microvasculature network from noisy and low-resolution fluorescence microscopy data that does not require the detailed segmentation of the vessel structure is proposed here. The method is most appropriate for problems where the tortuosity of the network is relatively low and proceeds by directly computing a piecewise linear approximation to the vasculature skeleton through the construction of a graph in three dimensions whose edges represent the skeletal approximation and vertices are located at Critical Points (CPs) on the microvasculature. The CPs are defined as vessel junctions or locations of relatively large curvature along the centerline of a vessel. Our method consists of two phases. First, we provide a CP detection technique that, for junctions in particular, does not require any a priori geometric information such as direction or degree. Second, connectivity between detected nodes is determined via the solution of a Binary Integer Program (BIP) whose variables determine whether a potential edge between nodes is or is not included in the final graph. The utility function in this problem reflects both intensity-based and structural information along the path connecting the two nodes. Qualitative and quantitative results confirm the usefulness and accuracy of this method. This approach provides a mean of correctly capturing the connectivity patterns in vessels that are missed by more traditional segmentation and binarization schemes because of imperfections in the images which manifest as dim or broken vessels. Copyright © 2014 Elsevier B.V. All rights reserved.

Forest representation of vessels in cone-beam computed tomographic angiography.

PubMed

Chen, Zikuan; Ning, Ruola

2005-01-01

Cone-beam computed tomographic angiography (CBCTA) provides a fast three-dimensional (3D) vascular imaging modality, aiming at digitally representing the spatial vascular structure in an angiographic volume. Due to the finite coverage of cone-beam scan, as well as the volume cropping in volumetric image processing, an angiographic volume may fail to contain a whole vascular tree, but rather consist of a multitude of vessel segments or subtrees. As such, it is convenient to represent multitudinal components by a forest. The vessel tracking issue then becomes component characterization/identification in the forest. The forest representation brings several conveniences for vessel tracking: (1) to sort and count the vessels in an angiographic volume, for example, according to spatial occupancy and skeleton pathlength; (2) to single out a vessel and perform in situ 3D measurement and 3D visualization in the support space; (3) to delineate individual vessels from the original angiographic volume; and (4) to cull the forest by getting rid of non-vessels and small vessels. A 3D skeletonization is used to generate component skeletons. For tree construction from skeletons, we suggest a pathlength-based procedure, which lifts the restrictions of unit-width skeleton and root determination. We experimentally demonstrate the forest representation of a dog's carotid arteries in a CBCTA system. In principle, the forest representation is useful for managing vessels in both 2D angiographic images and 3D angiographic volumes.

Discontinuity stresses in metallic pressure vessels

NASA Technical Reports Server (NTRS)

1971-01-01

The state of the art, criteria, and recommended practices for the theoretical and experimental analyses of discontinuity stresses and their distribution in metallic pressure vessels for space vehicles are outlined. The applicable types of pressure vessels include propellant tanks ranging from main load-carrying integral tank structure to small auxiliary tanks, storage tanks, solid propellant motor cases, high pressure gas bottles, and pressurized cabins. The major sources of discontinuity stresses are discussed, including deviations in geometry, material properties, loads, and temperature. The advantages, limitations, and disadvantages of various theoretical and experimental discontinuity analysis methods are summarized. Guides are presented for evaluating discontinuity stresses so that pressure vessel performance will not fall below acceptable levels.

Guide for inservice inspection of ground-based pressure vessels and systems

NASA Technical Reports Server (NTRS)

1976-01-01

This guide includes recommendations for inservice inspection and recertification of ground based, unfired pressure vessels and all pressurized systems including those served by fired pressure vessels hereinafter referred to as pressure vessels, systems and components of systems. It covers the vast array of pound based industrial and special purpose pressurized components and systems used at NASA field installations for research and development and those utility systems and components that require more than routine maintenance to insure continued structural integrity for their useful life. Through surveillance and correction of inservice deterioration, NASA will maintain a safe working environment for their own and contractor personnel, safety for the public sector and protection against loss of capital investment.

Heat transfer of molten metal layers in severe accidents

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

Wong, Seung Kai; Walton, A.; Yang, Zhilin

1997-12-01

In some scenarios of severe accidents of light water reactors, a layer of molten metal from internal structural components of the pressure vessel is predicted to occur on top of a ceramic core debris in the lower head. The layer transfers the heat generated in the ceramic pool to the side wall of the vessel, causing the latter to melt. This problem has been investigated by Theofanous et al. for the advanced light water reactor AP600 in the context of the accident management strategy of ex-vessel cooling, and the conclusion was drawn that the melting does not seriously compromise themore » integrity of the pressure vessel.« less

Cryogenic glass-filament-wound tank evaluation

NASA Technical Reports Server (NTRS)

Morris, E. E.; Landes, R. E.

1971-01-01

High-pressure glass-filament-wound fluid storage vessels with thin aluminum liners were designed, fabricated, and tested at ambient and cryogenic temperatures which demonstrated the feasibility of producing such vessels as well as high performance and light weight. Significant developments and advancements were made in solving problems associated with the thin metal liners in the tanks, including liner bonding to the overwrap and high strain magnification at the vessel polar bosses. The vessels had very high burst strengths, and failed in cyclic fatigue tests by local liner fracture and leakage without structural failure of the composite tank wall. The weight of the tanks was only 40 to 55% of comparable 2219-T87 aluminum and Inconel 718 tanks.

Fluid-Structure Model of Lymphatic Valve and Vessel

NASA Astrophysics Data System (ADS)

Wolf, Ki; Ballard, Matthew; Nepiyushchikh, Zhanna; Razavi, Mohammad; Dixon, Brandon; Alexeev, Alexander

The lymphatic system is a part of the circulatory system that performs a range of important functions such as transportation of interstitial fluid, fatty acid, and immune cells. The lymphatic vessels are composed of contractile walls to pump lymph against adverse pressure gradient and lymphatic valves that prevent back flow. Despite the importance of lymphatic system, the contribution of mechanical and geometric changes of lymphatic valves and vessels in pathologies of lymphatic dysfunction, such as lymphedema, is not well understood. We developed a coupled fluid-solid computational model to simultaneously simulate a lymphatic vessel, valve, and flow. A lattice Boltzmann model is used to represent the fluid component, while lattice spring model is used for the solid component of the lymphatic vessel, whose mechanical properties are derived experimentally. Behaviors such as lymph flow pattern and lymphatic valve performance against backflow and adverse pressure gradient under varied parameters of lymphatic valve and vessel geometry and mechanical properties are investigated to provide a better insight into the dynamics of lymphatic vessels, valves, and system and give insight into how they might fail in disease. NSF CMMI-1635133.

Comparative analysis of methods for extracting vessel network on breast MRI images

NASA Astrophysics Data System (ADS)

Gaizer, Bence T.; Vassiou, Katerina G.; Lavdas, Eleftherios; Arvanitis, Dimitrios L.; Fezoulidis, Ioannis V.; Glotsos, Dimitris T.

2017-11-01

Digital processing of MRI images aims to provide an automatized diagnostic evaluation of regular health screenings. Cancerous lesions are proven to cause an alteration in the vessel structure of the diseased organ. Currently there are several methods used for extraction of the vessel network in order to quantify its properties. In this work MRI images (Signa HDx 3.0T, GE Healthcare, courtesy of University Hospital of Larissa) of 30 female breasts were subjected to three different vessel extraction algorithms to determine the location of their vascular network. The first method is an experiment to build a graph over known points of the vessel network; the second algorithm aims to determine the direction and diameter of vessels at these points; the third approach is a seed growing algorithm, spreading selection to neighbors of the known vessel pixels. The possibilities shown by the different methods were analyzed, and quantitative measurements were performed. The data provided by these measurements showed no clear correlation with the presence or malignancy of tumors, based on the radiological diagnosis of skilled physicians.

Monitoring and Deformation Analysis of Groynes Using Tls at the River Elbe

NASA Astrophysics Data System (ADS)

Tschirschwitz, F.; Mechelke, K.; Jansch, H.; Kersten, T. P.

2016-06-01

To enter the Port of Hamburg, one of Europe's busiest ports all vessels need to navigate around 145 km along the Elbe river, a tide influenced navigation channel. To protect the Elbe shoreline from erosion and to channel the waterway groynes (rigid hydraulic structures) have been built along the river. In the past years since ca. 2001 there has been a large increase in damage of groynes structural integrity at parts of the German waterways. The reason for this was determined in the ever growing size of container vessels passing by and inducing long periodical primary waves which have such a force that they erode the groynes rock structure. To analyse and improve the groynes structural resistance for vessel-induced long periodical wave loads an in-situ study is carried out at Juelssand, located at the Elbe river estuary. Over a period of two years the change of the geometrical structure of two different groyne shapes is monitored automatically by utilising two terrestrial laser scanners mounted in protective housings, located each on a 12 m high platform. The self-contained monitoring systems perform scanning of the two groynes one to two times a day at low tide, as the structures are fully submerged at high tide. The long-periodical wave loads are also determined using pressure sensors in each groyne. To correlate the captured data with vessel events and analyse the effects, vessel related parameters are recorded utilizing the Automatic Identification System (AIS). This paper describes the automated processes for the data acquisition and focusses on the deformation that is calculated using current, extended and new algorithms of the Point Cloud Library. It shows the process chain from the acquisition of raw scan files from an elevated station to the filtering of point cloud, the registration, the calculation of pointwise changes and the aggregation to a grid for later correlation with ship parameters. When working outdoor in all kinds of weather conditions, the processes and equipment need to be robust and account for various cases and situations. This is especially applicable for the algorithms, which need to be adaptable to different scenarios like wet surfaces or snow and unwelcome objects ranging from flotsam to birds sitting on the groyne. At the current stage of the research, deformation in the magnitude of a couple of decimetres is observable. The orientation and location of the deformation is on the seaward side and corresponds to the lower distance of vessels leaving the harbour.

A pilot study to image the vascular network of small melanocytic choroidal tumors with speckle noise-free 1050-nm swept source optical coherence tomography (OCT choroidal angiography).

PubMed

Maloca, Peter; Gyger, Cyrill; Hasler, Pascal W

2016-06-01

To visualize and measure the vascular network of melanocytic choroidal tumors with speckle noise-free swept source optical coherence tomography (SS-OCT choroidal angiography). Melanocytic choroidal tumors from 24 eyes were imaged with 1050-nm optical coherence tomography (Topcon DRI OCT-1 Atlantis). A semi-automated algorithm was developed to remove speckle noise and to extract and measure the volume of the choroidal vessels from the obtained OCT data. In all cases, analysis of the choroidal vessels could be performed with SS-OCT without the need for pupillary dilation. The proposed method allows speckle noise-free, structure-guided visualization and measurement of the larger choroidal vessels in three dimensions. The obtained data suggest that speckle noise-free OCT may be more effective at identifying choroidal structures than traditional OCT methods. The measured volume of the extracted choroidal vessels of Haller's layer and Sattler's layer in the examined tumorous eyes was on average 0.982463955 mm(3) /982463956 μm(3) (range of 0.209764406 mm(3) /209764405.9 μm(3)to 1.78105544 mm(3) /1781055440 μm(3)). Full thickness obstruction of the choroidal vasculature by the tumor was found in 18 cases (72 %). In seven cases (18 %), choroidal vessel architecture did not show pronounced morphological abnormalities (18 %). Speckle noise-free OCT may serve as a new illustrative imaging technology and enhance visualization of the choroidal vessels without the need for dye injection. OCT can be used to identify and evaluate the choroidal vessels of melanocytic choroidal tumors, and may represent a potentially useful tool for imaging and monitoring of choroidal nevi and melanoma.

Automated detection of pulmonary embolism (PE) in computed tomographic pulmonary angiographic (CTPA) images: multiscale hierachical expectation-maximization segmentation of vessels and PEs

NASA Astrophysics Data System (ADS)

Zhou, Chuan; Chan, Heang-Ping; Hadjiiski, Lubomir M.; Chughtai, Aamer; Patel, Smita; Cascade, Philip N.; Sahiner, Berkman; Wei, Jun; Ge, Jun; Kazerooni, Ella A.

2007-03-01

CT pulmonary angiography (CTPA) has been reported to be an effective means for clinical diagnosis of pulmonary embolism (PE). We are developing a computer-aided detection (CAD) system to assist radiologist in PE detection in CTPA images. 3D multiscale filters in combination with a newly designed response function derived from the eigenvalues of Hessian matrices is used to enhance vascular structures including the vessel bifurcations and suppress non-vessel structures such as the lymphoid tissues surrounding the vessels. A hierarchical EM estimation is then used to segment the vessels by extracting the high response voxels at each scale. The segmented vessels are pre-screened for suspicious PE areas using a second adaptive multiscale EM estimation. A rule-based false positive (FP) reduction method was designed to identify the true PEs based on the features of PE and vessels. 43 CTPA scans were used as an independent test set to evaluate the performance of PE detection. Experienced chest radiologists identified the PE locations which were used as "gold standard". 435 PEs were identified in the artery branches, of which 172 and 263 were subsegmental and proximal to the subsegmental, respectively. The computer-detected volume was considered true positive (TP) when it overlapped with 10% or more of the gold standard PE volume. Our preliminary test results show that, at an average of 33 and 24 FPs/case, the sensitivities of our PE detection method were 81% and 78%, respectively, for proximal PEs, and 79% and 73%, respectively, for subsegmental PEs. The study demonstrates the feasibility that the automated method can identify PE accurately on CTPA images. Further study is underway to improve the sensitivity and reduce the FPs.

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.

46 CFR 154.188 - Membrane tank: Inner hull steel.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Membrane tank: Inner hull steel. 154.188 Section 154.188... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Hull Structure § 154.188 Membrane tank: Inner hull steel. For a vessel with membrane tanks, the inner hull...

33 CFR 67.15-1 - Lights and signals on attendant vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lights and signals on attendant vessels. 67.15-1 Section 67.15-1 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Miscellaneous...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2014 CFR

2014-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2011 CFR

2011-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2012 CFR

2012-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2010 CFR

2010-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2013 CFR

2013-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-20 - Inorganic acids.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Pressure vessel type cargo tanks shall be independent of the vessel's structure and shall be designed for the maximum pressure to which they may be subjected when compressed air is used to discharge the cargo... ventilation. (g) A separator shall be fitted in compressed air lines to the tank when air pressure is used to...

46 CFR 151.50-20 - Inorganic acids.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Pressure vessel type cargo tanks shall be independent of the vessel's structure and shall be designed for the maximum pressure to which they may be subjected when compressed air is used to discharge the cargo... ventilation. (g) A separator shall be fitted in compressed air lines to the tank when air pressure is used to...

46 CFR 151.50-20 - Inorganic acids.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Pressure vessel type cargo tanks shall be independent of the vessel's structure and shall be designed for the maximum pressure to which they may be subjected when compressed air is used to discharge the cargo... ventilation. (g) A separator shall be fitted in compressed air lines to the tank when air pressure is used to...

Liner-less Tanks for Space Application - Design and Manufacturing Considerations

NASA Technical Reports Server (NTRS)

Jones, Brian H.; Li, Min-Chung

2003-01-01

Composite pressure vessels, used extensively for gas and fuel containment in space vehicles, are generally constructed with a metallic liner, while the fiber reinforcement carries the major portion of the pressure-induced load. The design is dominated by the liner s low strain at yield since the reinforcing fibers cannot operate at their potential load-bearing capability without resorting to pre-stressing (or autofrettaging). An ultra high-efficiency pressure vessel, which operates at the optimum strain capability of the fibers, can be potentially achieved with a liner-less construction. This paper discusses the design and manufacturing challenges to be overcome in the development of such a pressure vessel. These include: (1) gas/liquid containment and permeation, (2) design and structural analysis, and (3) manufacturing process development. The paper also presents the development and validation tests on a liner-less pressure vessel developed by Kaiser Compositek Inc. (KCI). It should be noted that KCI s liner-less tank exhibits a highly controlled leak-before-burst mode. This feature results in a structure having the highest level of safety.

49 CFR 176.120 - Lightning protection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... or structure from its extremity and throughout to the main body of the hull structure. (Steel masts... grounded to the sea must be provided on any mast or similar structure on a vessel on which Class 1...

49 CFR 176.120 - Lightning protection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... or structure from its extremity and throughout to the main body of the hull structure. (Steel masts... grounded to the sea must be provided on any mast or similar structure on a vessel on which Class 1...

49 CFR 176.120 - Lightning protection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... or structure from its extremity and throughout to the main body of the hull structure. (Steel masts... grounded to the sea must be provided on any mast or similar structure on a vessel on which Class 1...

49 CFR 176.120 - Lightning protection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... or structure from its extremity and throughout to the main body of the hull structure. (Steel masts... grounded to the sea must be provided on any mast or similar structure on a vessel on which Class 1...

49 CFR 176.120 - Lightning protection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... or structure from its extremity and throughout to the main body of the hull structure. (Steel masts... grounded to the sea must be provided on any mast or similar structure on a vessel on which Class 1...

Distributed sensing of Composite Over-wrapped Pressure Vessels using Fiber-Bragg Gratings

NASA Technical Reports Server (NTRS)

Grant, Joseph

2005-01-01

The increasing use of advanced composite materials in the wide range of applications including Space Structures is a great impetus to the development of smart materials. These materials offer a wide range of possibilities within the space program. But before they can be reliably incorporated into space flight applications, additional understanding is required in the area of damage tolerance of these materials. Efforts to enhance our understanding of failure modes, mechanical properties, long and short term environmental effects, cyclic damage accumulation and residual strength are needed. Thus we have employed the use of fiber optical sensors which offers an excellent opportunity exploit these materials through monitoring and characterizing their mechanical properties and thus the integrity of structures made from such materials during their life cycle. Use of these optical innovations provides an insight into structures that have not been available in the past, as well as the technology available to provide real time health monitoring throughout its life cycle. The embedded fiber optical sensor shows a clearly detectable sensitivity to changes in the near strain and stress fields of the host structure promoted by mechanical or thermal loading or, in certain conditions, structural damage. The last ten years have seen a large increase in the use of FBG based monitoring systems in a broad range of applications. Fiber Bragg gratings are use to monitor the structural properties of composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in composite structures. The fiber Bragg sensors are both embedded within the composite laminates and bonded to the surface of the vessel with varying orientations with respect to the carbon fiber in the epoxy matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 4400 psi. This is done at both ambient and cryogenic temperatures using water and liquid nitrogen. The recorded response is compared with the response from conventional strain gauge also present on the vessel. Additionally, several vessels were tested that had been damaged to simulate different type of events, such as cut tow, delimitation and impact damage.

Retinal vessel enhancement based on the Gaussian function and image fusion

NASA Astrophysics Data System (ADS)

Moraru, Luminita; Obreja, Cristian Dragoş

2017-01-01

The Gaussian function is essential in the construction of the Frangi and COSFIRE (combination of shifted filter responses) filters. The connection of the broken vessels and an accurate extraction of the vascular structure is the main goal of this study. Thus, the outcome of the Frangi and COSFIRE edge detection algorithms are fused using the Dempster-Shafer algorithm with the aim to improve detection and to enhance the retinal vascular structure. For objective results, the average diameters of the retinal vessels provided by Frangi, COSFIRE and Dempster-Shafer fusion algorithms are measured. These experimental values are compared to the ground truth values provided by manually segmented retinal images. We prove the superiority of the fusion algorithm in terms of image quality by using the figure of merit objective metric that correlates the effects of all post-processing techniques.

Immersive volume rendering of blood vessels

NASA Astrophysics Data System (ADS)

Long, Gregory; Kim, Han Suk; Marsden, Alison; Bazilevs, Yuri; Schulze, Jürgen P.

2012-03-01

In this paper, we present a novel method of visualizing flow in blood vessels. Our approach reads unstructured tetrahedral data, resamples it, and uses slice based 3D texture volume rendering. Due to the sparse structure of blood vessels, we utilize an octree to efficiently store the resampled data by discarding empty regions of the volume. We use animation to convey time series data, wireframe surface to give structure, and utilize the StarCAVE, a 3D virtual reality environment, to add a fully immersive element to the visualization. Our tool has great value in interdisciplinary work, helping scientists collaborate with clinicians, by improving the understanding of blood flow simulations. Full immersion in the flow field allows for a more intuitive understanding of the flow phenomena, and can be a great help to medical experts for treatment planning.

Landmark-Based 3D Elastic Registration of Pre- and Postoperative Liver CT Data

NASA Astrophysics Data System (ADS)

Lange, Thomas; Wörz, Stefan; Rohr, Karl; Schlag, Peter M.

The qualitative and quantitative comparison of pre- and postoperative image data is an important possibility to validate computer assisted surgical procedures. Due to deformations after surgery a non-rigid registration scheme is a prerequisite for a precise comparison. Interactive landmark-based schemes are a suitable approach. Incorporation of a priori knowledge about the anatomical structures to be registered may help to reduce interaction time and improve accuracy. Concerning pre- and postoperative CT data of oncological liver resections the intrahepatic vessels are suitable anatomical structures. In addition to using landmarks at vessel branchings, we here introduce quasi landmarks at vessel segments with anisotropic localization precision. An experimental comparison of interpolating thin-plate splines (TPS) and Gaussian elastic body splines (GEBS) as well as approximating GEBS on both types of landmarks is performed.

Rational drug design and synthesis of molecules targeting the angiotensin II type 1 and type 2 receptors.

PubMed

Kellici, Tahsin F; Tzakos, Andreas G; Mavromoustakos, Thomas

2015-03-02

The angiotensin II (Ang II) type 1 and type 2 receptors (AT1R and AT2R) orchestrate an array of biological processes that regulate human health. Aberrant function of these receptors triggers pathophysiological responses that can ultimately lead to death. Therefore, it is important to design and synthesize compounds that affect beneficially these two receptors. Cardiovascular disease, which is attributed to the overactivation of the vasoactive peptide hormone Αng II, can now be treated with commercial AT1R antagonists. Herein, recent achievements in rational drug design and synthesis of molecules acting on the two AT receptors are reviewed. Quantitative structure activity relationships (QSAR) and molecular modeling on the two receptors aim to assist the search for new active compounds. As AT1R and AT2R are GPCRs and drug action is localized in the transmembrane region the role of membrane bilayers is exploited. The future perspectives in this field are outlined. Tremendous progress in the field is expected if the two receptors are crystallized, as this will assist the structure based screening of the chemical space and lead to new potent therapeutic agents in cardiovascular and other diseases.

Glioblastoma stem cell differentiation into endothelial cells evidenced through live-cell imaging.

PubMed

Mei, Xin; Chen, Yin-Sheng; Chen, Fu-Rong; Xi, Shao-Yan; Chen, Zhong-Ping

2017-08-01

Glioblastoma cell-initiated vascularization is an alternative angiogenesis called vasculogenic mimicry. However, current knowledge on the mechanism of de novo vessel formation from glioblastoma stem cells (GSCs) is limited. Sixty-four glioblastoma samples from patients and 10 fluorescent glioma xenograft samples were examined by immunofluorescence staining for endothelial marker (CD34 and CD31) and glial cell marker (glial fibrillary acidic protein [GFAP]) expression. GSCs were then isolated from human glioblastoma tissue and CD133+/Sox2+ red fluorescent protein-containing (RFP)-GSC-1 cells were established. The ability of these cells to form vascular structures was examined by live-cell imaging of 3D cultures. CD34-GFAP or CD31-GFAP coexpressing glioblastoma-derived endothelial cells (GDEC) were found in 30 of 64 (46.9%) of clinical glioblastoma samples. In those 30 samples, GDEC were found to form vessel structures in 21 (70%) samples. Among 21 samples with GDEC vessels, the CD34+ GDEC vessels and CD31+ GDEC vessels accounted for about 14.16% and 18.08% of total vessels, respectively. In the xenograft samples, CD34+ GDEC were found in 7 out of 10 mice, and 4 out of 7 mice had CD34+ GDEC vessels. CD31+ GDEC were also found in 7 mice, and 4 mice had CD31+ GDEC vessels (10 mice in total). Through live-cell imaging, we observed gradual CD34 expression when cultured with vascular endothelial growth factor in some glioma cells, and a dynamic increase in endothelial marker expression in RFP-GSC-1 in vitro was recorded. Cells expressed CD34 (9.46%) after 6 hours in culture. The results demonstrated that GSCs may differentiate into endothelial cells and promote angiogenesis in glioblastomas. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Progressive Fracture and Damage Tolerance of Composite Pressure Vessels

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Gotsis, Pascal K.; Minnetyan, Levon

1997-01-01

Structural performance (integrity, durability and damage tolerance) of fiber reinforced composite pressure vessels, designed for pressured shelters for planetary exploration, is investigated via computational simulation. An integrated computer code is utilized for the simulation of damage initiation, growth, and propagation under pressure. Aramid fibers are considered in a rubbery polymer matrix for the composite system. Effects of fiber orientation and fabrication defect/accidental damages are investigated with regard to the safety and durability of the shelter. Results show the viability of fiber reinforced pressure vessels as damage tolerant shelters for planetary colonization.

46 CFR 154.176 - Longitudinal contiguous hull structure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Longitudinal contiguous hull structure. 154.176 Section... Equipment Hull Structure § 154.176 Longitudinal contiguous hull structure. (a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet the...

46 CFR 154.174 - Transverse contiguous hull structure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Transverse contiguous hull structure. 154.174 Section... Equipment Hull Structure § 154.174 Transverse contiguous hull structure. (a) The transverse contiguous hull...) The transverse contiguous hull structure of a vessel having cargo containment systems with secondary...

46 CFR 154.176 - Longitudinal contiguous hull structure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Longitudinal contiguous hull structure. 154.176 Section... Equipment Hull Structure § 154.176 Longitudinal contiguous hull structure. (a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet the...

46 CFR 154.176 - Longitudinal contiguous hull structure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Longitudinal contiguous hull structure. 154.176 Section... Equipment Hull Structure § 154.176 Longitudinal contiguous hull structure. (a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet the...

46 CFR 154.176 - Longitudinal contiguous hull structure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Longitudinal contiguous hull structure. 154.176 Section... Equipment Hull Structure § 154.176 Longitudinal contiguous hull structure. (a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet the...

46 CFR 154.176 - Longitudinal contiguous hull structure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Longitudinal contiguous hull structure. 154.176 Section... Equipment Hull Structure § 154.176 Longitudinal contiguous hull structure. (a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet the...

Anatomy of the obturator region: relations to a trans-obturator sling.

PubMed

Whiteside, James L; Walters, Mark D

2004-01-01

Our objective was to determine the relationships between a trans-obturator sling and anatomic structures within the obturator region. The obturator regions of six cadavers were dissected and distances from the mid-point of the ischiopubic ramus to the muscles, nerves, and vessels of the region were measured. A trans-obturator sling was placed and distances from the device to the same anatomic structures were determined. Four additional cadavers were dissected to determine the device route of passage. The obturator canal is on average 4.4 cm from the midpoint of the ischiopubic rami. The trans-obturator sling passes on average 2.4 cm inferior-medial to the obturator canal. The anterior and posterior divisions of the obturator nerve are on average 3.4 and 2.8 cm, respectively, from a passed trans-obturator device. The device passed on average 1.1 cm from the most medial branch of the obturator vessels. Vascular and nerve structures are within 1-3 cm of the path of any device passed through the obturator foramen. A trans-obturator sling risks injury to these structures, although the small caliber of the vessels and the confined space in which they would bleed make the consequences of injury uncertain.

Digital Cellular Solid Pressure Vessels: A Novel Approach for Human Habitation in Space

NASA Technical Reports Server (NTRS)

Cellucci, Daniel; Jenett, Benjamin; Cheung, Kenneth C.

2017-01-01

It is widely assumed that human exploration beyond Earth's orbit will require vehicles capable of providing long duration habitats that simulate an Earth-like environment - consistent artificial gravity, breathable atmosphere, and sufficient living space- while requiring the minimum possible launch mass. This paper examines how the qualities of digital cellular solids - high-performance, repairability, reconfigurability, tunable mechanical response - allow the accomplishment of long-duration habitat objectives at a fraction of the mass required for traditional structural technologies. To illustrate the impact digital cellular solids could make as a replacement to conventional habitat subsystems, we compare recent proposed deep space habitat structural systems with a digital cellular solids pressure vessel design that consists of a carbon fiber reinforced polymer (CFRP) digital cellular solid cylindrical framework that is lined with an ultra-high molecular weight polyethylene (UHMWPE) skin. We use the analytical treatment of a linear specific modulus scaling cellular solid to find the minimum mass pressure vessel for a structure and find that, for equivalent habitable volume and appropriate safety factors, the use of digital cellular solids provides clear methods for producing structures that are not only repairable and reconfigurable, but also higher performance than their conventionally manufactured counterparts.

Increasing use of less-invasive hemodynamic monitoring in 3 specialty surgical intensive care units: a 5-year experience at a tertiary medical center.

PubMed

Kirton, Orlando C; Calabrese, Rebecca C; Staff, Ilene

2015-01-01

Less-invasive hemodynamic monitoring (eg, esophageal doppler monitoring [EDM] and arterial pressure contour analysis, FloTrac) is increasingly used as an alternative to pulmonary artery catheters (PACs) in critically ill intensive care unit (ICU). The decrease in use of PACs is not associated with increased mortality. Five-year retrospective review of 1894 hemodynamically monitored patients admitted to 3 surgical ICUs in a university-affiliate, tertiary care urban hospital. Data included the number of admissions, diagnosis-related group discharge case mix, length of stay, insertion of monitoring devices (PAC, EDM, and FloTrac probes), administered intravenous vasoactive agents (β-predominant agonists--dobutamine, epinephrine, and dopamine; vasopressors--norepinephrine and phenylephrine), and mortality. Data from hospital administrative databases were compiled to create patient characteristic and monitoring variables across a 5-year time period, 2005 to 2009 inclusive. Chi-square for independent proportions, 1-way analysis of variance, and Kruskal-Wallis tests were used; tests for trend were conducted. An α level of .05 was considered significant. Statistical Package for the Social Sciences v14 was used for all statistical testing. There was a significant change in the type of hemodynamic monitors inserted in 2 of the 3 surgical ICUs (in the general surgery and neurointensive care but not in the cardiac ICU) from PACs to less-invasive devices (FloTrac or EDM) during the 5-year study period (P < .001). There was no change in mortality rate over the time period (P = .492). There was an overall increase in the proportion of monitored patients who received intravenous vasoactive agents (P < .001) with a progressive shift from β-agonists to vasopressors (P < .002). Multivariate analyses indicated that age, case mix, and use of vasoactive agents were all independent predictors of inhospital mortality (P = .001) but that type of monitoring was not (P = .638). In a 5-year period, the decreased insertions of PACs were replaced by increased utilization of less-invasive hemodynamic monitoring devices. This change in practice did not adversely impact mortality. © The Author(s) 2013.

Rifaximin has no effect on hemodynamics in decompensated cirrhosis: A randomized, double-blind, placebo-controlled trial.

PubMed

Kimer, Nina; Pedersen, Julie Steen; Busk, Troels Malte; Gluud, Lise Lotte; Hobolth, Lise; Krag, Aleksander; Møller, Søren; Bendtsen, Flemming

2017-02-01

Decompensated cirrhosis is characterized by disturbed systemic and splanchnic hemodynamics. Bacterial translocation from the gut is considered the key driver in this process. Intestinal decontamination with rifaximin may improve hemodynamics. This double-blind, randomized, controlled trial (clinicaltrials.gov, NCT01769040) investigates the effects of rifaximin on hemodynamics, renal function, and vasoactive hormones. We randomized 54 stable outpatients with cirrhosis and ascites to rifaximin 550 mg twice a day (n = 36) or placebo twice a day (n = 18). Forty-five patients were male, mean age 56 years (±8.4), average Child score 8.3 (±1.3), and Model for End-Stage Liver Disease score 11.7 (±3.9). Measurements of hepatic venous pressure gradient, cardiac output, and systemic vascular resistance were made at baseline and after 4 weeks. The glomerular filtration rate and plasma renin, noradrenaline, lipopolysaccharide binding protein, troponin T, and brain natriuretic peptide levels were measured. Rifaximin had no effect on hepatic venous pressure gradient, mean 16.8 ± 3.8 mm Hg at baseline versus 16.6 ± 5.3 mm Hg at follow-up, compared to the placebo, mean 16.4 ± 4 mm Hg at baseline versus 16.3 ± 4.4 mm Hg at follow-up, P = 0.94. No effect was found on cardiac output, mean 6.9 ± 1.7 L/min at baseline versus 6.9 ± 2.3 L/min at follow-up, compared to placebo, mean 6.6 ± 1.9 L/min at baseline compared to 6.5 ±2.1 L/min at follow-up, P = 0.66. No effects on the glomerular filtration rate, P = 0.14, or vasoactive hormones were found. Subgroup analyses on patients with increased lipopolysaccharide binding protein and systemic vascular resistance below the mean (1,011 dynes × s/cm 5 ) revealed no effect of rifaximin. Four weeks of treatment with rifaximin did not reduce the hepatic venous pressure gradient or improve systemic hemodynamics in patients with cirrhosis and ascites; rifaximin did not affect glomerular filtration rate or levels of vasoactive hormones. (Hepatology 2017;65:592-603). © 2016 by the American Association for the Study of Liver Diseases.

Double-Blind Prospective Randomized Controlled Trial of Dopamine Versus Epinephrine as First-Line Vasoactive Drugs in Pediatric Septic Shock.

PubMed

Ventura, Andréa M C; Shieh, Huei Hsin; Bousso, Albert; Góes, Patrícia F; de Cássia F O Fernandes, Iracema; de Souza, Daniela C; Paulo, Rodrigo Locatelli Pedro; Chagas, Fabiana; Gilio, Alfredo E

2015-11-01

The primary outcome was to compare the effects of dopamine or epinephrine in severe sepsis on 28-day mortality; secondary outcomes were the rate of healthcare-associated infection, the need for other vasoactive drugs, and the multiple organ dysfunction score. Double-blind, prospective, randomized controlled trial from February 1, 2009, to July 31, 2013. PICU, Hospital Universitário da Universidade de São Paulo, Brazil. Consecutive children who are 1 month to 15 years old and met the clinical criteria for fluid-refractory septic shock. Exclusions were receiving vasoactive drug(s) prior to hospital admission, having known cardiac disease, having already participated in the trial during the same hospital stay, refusing to participate, or having do-not-resuscitate orders. Patients were randomly assigned to receive either dopamine (5-10 μg/kg/min) or epinephrine (0.1-0.3 μg/kg/min) through a peripheral or intraosseous line. Patients not reaching predefined stabilization criteria after the maximum dose were classified as treatment failure, at which point the attending physician gradually stopped the study drug and started another catecholamine. Physiologic and laboratory data were recorded. Baseline characteristics were described as proportions and mean (± SD) and compared using appropriate statistical tests. Multiple regression analysis was performed, and statistical significance was defined as a p value of less than 0.05. Baseline characteristics and therapeutic interventions for the 120 children enrolled (63, dopamine; 57, epinephrine) were similar. There were 17 deaths (14.2%): 13 (20.6%) in the dopamine group and four (7%) in the epinephrine group (p=0.033). Dopamine was associated with death (odds ratio, 6.5; 95% CI, 1.1-37.8; p=0.037) and healthcare-associated infection (odds ratio, 67.7; 95% CI, 5.0-910.8; p=0.001). The use of epinephrine was associated with a survival odds ratio of 6.49. Dopamine was associated with an increased risk of death and healthcare-associated infection. Early administration of peripheral or intraosseous epinephrine was associated with increased survival in this population. Limitations should be observed while interpreting these results.

Three dimensional contact/impact methodology

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

Kulak, R.F.

1987-01-01

The simulation of three-dimensional interface mechanics between reactor components and structures during static contact or dynamic impact is necessary to realistically evaluate their structural integrity to off-normal loads. In our studies of postulated core energy release events, we have found that significant structure-structure interactions occur in some reactor vessel head closure designs and that fluid-structure interactions occur within the reactor vessel. Other examples in which three-dimensional interface mechanics play an important role are: (1) impact response of shipping casks containing spent fuel, (2) whipping pipe impact on reinforced concrete panels or pipe-to-pipe impact after a pipe break, (3) aircraft crashmore » on secondary containment structures, (4) missiles generated by turbine failures or tornados, and (5) drops of heavy components due to lifting accidents. The above is a partial list of reactor safety problems that require adequate treatment of interface mechanics and are discussed in this paper.« less