A brain slice bath for physiology and compound microscopy, with dual-sided perifusion.

PubMed

Heyward, P M

2010-12-01

Contemporary in vitro brain slice studies can employ compound microscopes to identify individual neurons or their processes for physiological recording or imaging. This requires that the bath used to maintain the tissue fits within the working distances of a water-dipping objective and microscope condenser. A common means of achieving this is to maintain thin tissue slices on the glass floor of a recording bath, exposing only one surface of the tissue to oxygenated bathing medium. Emerging evidence suggests that physiology can be compromised by this approach. Flowing medium past both sides of submerged brain slices is optimal, but recording baths utilizing this principle are not readily available for use on compound microscopes. This paper describes a tissue bath designed specifically for microscopy and physiological recording, in which temperature-controlled medium flows past both sides of the slices. A particular feature of this design is the use of concentric mesh rings to support and transport the live tissue without mechanical disturbance. The design is also easily adapted for use with thin acute slices, cultured slices, and acutely dispersed or cultured cells maintained either on cover slips or placed directly on the floor of the bath. The low profile of the bath provides a low angle of approach for electrodes, and allows use of standard condensers, nosepieces and water-dipping objective lenses. If visualization of individual neurons is not required, the bath can be mounted on a simple stand and used with a dissecting microscope. Heating is integral to the bath, and any temperature controller capable of driving a resistive load can be used. The bath is robust, readily constructed and requires minimal maintenance. Full construction and operation details are given. © 2010 The Author Journal of Microscopy © 2010 The Royal Microscopical Society.

Effect of slice thickness on brain magnetic resonance image texture analysis

PubMed Central

2010-01-01

Background The accuracy of texture analysis in clinical evaluation of magnetic resonance images depends considerably on imaging arrangements and various image quality parameters. In this paper, we study the effect of slice thickness on brain tissue texture analysis using a statistical approach and classification of T1-weighted images of clinically confirmed multiple sclerosis patients. Methods We averaged the intensities of three consecutive 1-mm slices to simulate 3-mm slices. Two hundred sixty-four texture parameters were calculated for both the original and the averaged slices. Wilcoxon's signed ranks test was used to find differences between the regions of interest representing white matter and multiple sclerosis plaques. Linear and nonlinear discriminant analyses were applied with several separate training and test sets to determine the actual classification accuracy. Results Only moderate differences in distributions of the texture parameter value for 1-mm and simulated 3-mm-thick slices were found. Our study also showed that white matter areas are well separable from multiple sclerosis plaques even if the slice thickness differs between training and test sets. Conclusions Three-millimeter-thick magnetic resonance image slices acquired with a 1.5 T clinical magnetic resonance scanner seem to be sufficient for texture analysis of multiple sclerosis plaques and white matter tissue. PMID:20955567

Isoproterenol effects evaluated in heart slices of human and rat in comparison to rat heart in vivo

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

Herrmann, Julia E.; Heale, Jason; Bieraugel, Mike

Human response to isoproterenol induced cardiac injury was evaluated by gene and protein pathway changes in human heart slices, and compared to rat heart slices and rat heart in vivo. Isoproterenol (10 and 100 μM) altered human and rat heart slice markers of oxidative stress (ATP and GSH) at 24 h. In this in vivo rat study (0.5 mg/kg), serum troponin concentrations increased with lesion severity, minimal to mild necrosis at 24 and 48 h. In the rat and the human heart, isoproterenol altered pathways for apoptosis/necrosis, stress/energy, inflammation, and remodeling/fibrosis. The rat and human heart slices were in anmore » apoptotic phase, while the in vivo rat heart exhibited necrosis histologically and further progression of tissue remodeling. In human heart slices genes for several heat shock 70 kD members were altered, indicative of stress to mitigate apoptosis. The stress response included alterations in energy utilization, fatty acid processing, and the up-regulation of inducible nitric oxide synthase, a marker of increased oxidative stress in both species. Inflammation markers linked with remodeling included IL-1α, Il-1β, IL-6 and TNFα in both species. Tissue remodeling changes in both species included increases in the TIMP proteins, inhibitors of matrix degradation, the gene/protein of IL-4 linked with cardiac fibrosis, and the gene Ccl7 a chemokine that induces collagen synthesis, and Reg3b a growth factor for cardiac repair. This study demonstrates that the initial human heart slice response to isoproterenol cardiac injury results in apoptosis, stress/energy status, inflammation and tissue remodeling at concentrations similar to that in rat heart slices. - Highlights: • Human response to isoproterenol induced cardiac injury evaluated in heart slices. • Isoproterenol altered apoptosis, energy, inflammation and remodeling pathways. • Human model verified by comparison to rat heart slices and rat heart in vivo. • Human and rat respond to isoproterenol at similar concentrations in vitro.« less

Combination of sodium chlorite and calcium propionate reduces enzymatic browning and microbial population of fresh-cut "Granny Smith" apples.

PubMed

Guan, Wenqiang; Fan, Xuetong

2010-03-01

Tissue browning and microbial growth are the main concerns associated with fresh-cut apples. In this study, effects of sodium chlorite (SC) and calcium propionate (CP), individually and combined, on quality and microbial population of apple slices were investigated. "Granny Smith" apple slices, dipped for 5 min in CP solutions at 0%, 0.5%, 1%, and 2% (w/v) either alone or in combination with 0.05% (w/v) SC, were stored at 3 and 10 degrees C for up to 14 d. Color, firmness, and microflora population were measured at 1, 7, and 14 d of storage. Results showed that CP alone had no significant effect on the browning of cut apples. Even though SC significantly inhibited tissue browning initially, the apple slices turned brown during storage at 10 degrees C. The combination of CP and SC was able to inhibit apple browning during storage. Samples treated with the combination of SC with CP did not show any detectable yeast and mold growth during the entire storage period at 3 degrees C. At 10 degrees C, yeast and mold count increased on apple slices during storage while CP reduced the increase. However, high concentrations of CP reduced the efficacy of SC in inactivating E. coli inoculated on apples. Overall, our results suggested that combination of SC with 0.5% and 1% CP could be used to inhibit tissue browning and maintain firmness while reducing microbial population. Practical Application: Apple slices, which contain antioxidants and other nutrient components, have emerged as popular snacks in food service establishments, school lunch programs, and for family consumption. However, the further growth of the industry is limited by product quality deterioration caused by tissue browning, short shelf-life due to microbial growth, and possible contamination with human pathogens during processing. Therefore, this study was conducted to develop treatments to reduce microbial population and tissue browning of "Granny Smith" apple slices. Results showed that an antimicrobial compound, sodium chlorite, is effective in not only eliminating microbes but also inhibiting tissue browning of apple slices. However, the compound caused tissue softening and its antibrowning effect was short-lived, lasting only for a few days. Combination of the compound with a calcium-containing food additive was able to improve firmness and freshness of apple slices while reducing population of Escherichia coli artificially inoculated on samples and inhibiting the growth of yeast and mold during storage.

Ex-vivo imaging of excised tissue using vital dyes and confocal microscopy

PubMed Central

Johnson, Simon; Rabinovitch, Peter

2012-01-01

Vital dyes routinely used for staining cultured cells can also be used to stain and image live tissue slices ex-vivo. Staining tissue with vital dyes allows researchers to collect structural and functional data simultaneously and can be used for qualitative or quantitative fluorescent image collection. The protocols presented here are useful for structural and functional analysis of viable properties of cells in intact tissue slices, allowing for the collection of data in a structurally relevant environment. With these protocols, vital dyes can be applied as a research tool to disease processes and properties of tissue not amenable to cell culture based studies. PMID:22752953

Organotypic hippocampal slice culture from the adult mouse brain: a versatile tool for translational neuropsychopharmacology.

PubMed

Kim, Hyunjeong; Kim, Eosu; Park, Minsun; Lee, Eun; Namkoong, Kee

2013-03-05

One of the most significant barriers towards translational neuropsychiatry would be an unavailability of living brain tissues. Although organotypic brain tissue culture could be a useful alternative enabling observation of temporal changes induced by various drugs in living brain tissues, a proper method to establish a stable organotypic brain slice culture system using adult (rather than neonatal) hippocampus has been still elusive. In this study, we evaluated our simple method using the serum-free culture medium for successful adult organotypic hippocampal slice culture. Several tens of hippocampal slices from a single adult mouse (3-5 months old) were cultured in serum-free versus serum-containing conventional culture medium for 30 days and underwent various experiments to validate the effects of the existence of serum in the culture medium. Neither the excessive regression of neuronal viability nor metabolic deficiency was observed in the serum-free medium culture in contrast to the serum-containing medium culture. Despite such viability, newly generated immature neurons were scarcely detected in the serum-free culture, suggesting that the original neurons in the brain slice persist rather than being replaced by neurogenesis. Key structural features of in vivo neural tissue constituting astrocytes, neural processes, and pre- and post-synapses were also well preserved in the serum-free culture. In conclusion, using the serum-free culture medium, the adult hippocampal slice culture system will serve as a promising ex vivo tool for various fields of neuroscience, especially for studies on aging-related neuropsychiatric disorders or for high throughput screening of potential agents working against such disorders. Copyright © 2012 Elsevier Inc. All rights reserved.

A Device for Long-Term Perfusion, Imaging, and Electrical Interfacing of Brain Tissue In vitro

PubMed Central

Killian, Nathaniel J.; Vernekar, Varadraj N.; Potter, Steve M.; Vukasinovic, Jelena

2016-01-01

Distributed microelectrode array (MEA) recordings from consistent, viable, ≥500 μm thick tissue preparations over time periods from days to weeks may aid in studying a wide range of problems in neurobiology that require in vivo-like organotypic morphology. Existing tools for electrically interfacing with organotypic slices do not address necrosis that inevitably occurs within thick slices with limited diffusion of nutrients and gas, and limited removal of waste. We developed an integrated device that enables long-term maintenance of thick, functionally active, brain tissue models using interstitial perfusion and distributed recordings from thick sections of explanted tissue on a perforated multi-electrode array. This novel device allows for automated culturing, in situ imaging, and extracellular multi-electrode interfacing with brain slices, 3-D cell cultures, and potentially other tissue culture models. The device is economical, easy to assemble, and integrable with standard electrophysiology tools. We found that convective perfusion through the culture thickness provided a functional benefit to the preparations as firing rates were generally higher in perfused cultures compared to their respective unperfused controls. This work is a step toward the development of integrated tools for days-long experiments with more consistent, healthier, thicker, and functionally more active tissue cultures with built-in distributed electrophysiological recording and stimulation functionality. The results may be useful for the study of normal processes, pathological conditions, and drug screening strategies currently hindered by the limitations of acute (a few hours long) brain slice preparations. PMID:27065793

Basic in vitro experiment on the adhesive effects of sheet-type hemostatic agents used in combination with a liquid fibrin sealant.

PubMed

Ishii, Keiichi; Kawashima, Hideki; Hayama, Takuma; Mayabashira, Sumika; Oka, Shiro; Sugimoto, Toshikado

2011-11-01

Various hemostatic agents have been used quite effectively for hemostasis, as well as for providing effective adhesion during laparoscopic partial nephrectomies. In this study, we investigated the adhesiveness to the renal tissue of some sheet-type hemostatic agents used in combination with a liquid fibrin sealant. In Experiment A, component solutions of the fibrin glue (liquid fibrin sealant) were dripped onto a kite string placed annularly on a porcine kidney slice. Then, one of the sheet-type hemostats--namely, the collagen, gelatin, or cellulose hemostat--was placed on the slices, and a string scale was used to measure the force needed to pull the string apart vertically from the kidney slice. Twelve slices were used for each group, and the weight data were analyzed statistically. The tissue adhering to each sheet-type hemostatic agent was fixed in formalin and sliced and then examined by light microscopy after hematoxylin and eosin staining. In Experiment B, the solutions were dripped onto the sheet-type hemostatic agent placed first on the slice, and the force needed for pulling apart the hemostat sheet from the slice was similarly examined. The combination of fibrin glue plus a collagen hemostat was clearly superior in Experiment A, but the hemostat and renal tissue could be pulled apart more easily in Experiment B. These results showed that fibrin glue could not exert its expected adhesive effect unless it is used in combination with another hemostatic agent or is directly applied to renal tissue. It is important to obtain further comparative data among agents and select the appropriate agents, taking into consideration the type of surgery.

Characterization of cortical neuronal and glial alterations during culture of organotypic whole brain slices from neonatal and mature mice.

PubMed

Staal, Jerome A; Alexander, Samuel R; Liu, Yao; Dickson, Tracey D; Vickers, James C

2011-01-01

Organotypic brain slice culturing techniques are extensively used in a wide range of experimental procedures and are particularly useful in providing mechanistic insights into neurological disorders or injury. The cellular and morphological alterations associated with hippocampal brain slice cultures has been well established, however, the neuronal response of mouse cortical neurons to culture is not well documented. In the current study, we compared the cell viability, as well as phenotypic and protein expression changes in cortical neurons, in whole brain slice cultures from mouse neonates (P4-6), adolescent animals (P25-28) and mature adults (P50+). Cultures were prepared using the membrane interface method. Propidium iodide labeling of nuclei (due to compromised cell membrane) and AlamarBlue™ (cell respiration) analysis demonstrated that neonatal tissue was significantly less vulnerable to long-term culture in comparison to the more mature brain tissues. Cultures from P6 animals showed a significant increase in the expression of synaptic markers and a decrease in growth-associated proteins over the entire culture period. However, morphological analysis of organotypic brain slices cultured from neonatal tissue demonstrated that there were substantial changes to neuronal and glial organization within the neocortex, with a distinct loss of cytoarchitectural stratification and increased GFAP expression (p<0.05). Additionally, cultures from neonatal tissue had no glial limitans and, after 14 DIV, displayed substantial cellular protrusions from slice edges, including cells that expressed both glial and neuronal markers. In summary, we present a substantial evaluation of the viability and morphological changes that occur in the neocortex of whole brain tissue cultures, from different ages, over an extended period of culture.

[Study of methods of decalcification for making united slices of tooth and affiliated periodontic tissues].

PubMed

Wang, Yu; Mu, Ya-bing; Miao, Lei-ying; Sun, Hong-chen; Li, Cheng-ku

2007-03-01

To study the methods of decalcification for making united slices of tooth and affiliated periodontic tissues. Twenty-one samples containing dog molars and affiliated periodontic tissues were divided into seven mean groups. The pH value of solution, time of decalcification, weight and volume of samples, and content of decalcified calcium were detected. The slices were observed by HE, specific, and immunohistochemical stain. The velocity of decalcification increased with decrease of solution pH. The weight of samples lightened by 37.61%, the volume reduced by 25.97% on average, and calcium decalcified was 174.49 mg per gram humid samples. The EDTA decalcification was slowest, but it was best. Decalcification was fast in Plank-Rycho solution while the section was worst, and faster in the formyl solution containing aluminium chloride than in EDTA, and the section was better. The 50% formyl solution containing aluminium chloride is an ideal decalcifying solution.

The synthesis and release of acetylcholine by depolarized hippocampal slices is increased by increased choline available in vitro prior to stimulation.

PubMed

Wecker, L

1991-10-01

The objective of these experiments was to determine whether preincubating hippocampal slices with choline provides precursor that can be used during a subsequent incubation to support or enhance the synthesis of acetylcholine (ACh). Slices were preincubated for 60 min with 0, 10, 25, or 50 microM choline, washed, resuspended, and then incubated for 10 min in choline-free buffer containing 4.74 (Krebs-Ringer bicarbonate, KRB) or 25 mM KCl. The tissue contents of ACh and choline were determined prior to and after the preincubation, as well as after the incubation; the amounts of ACh and choline released were measured, and ACh synthesis was calculated. Preincubation in the absence of choline increased the tissue content of ACh to 242% of original levels; preincubation with 10 microM choline did not lead to a further increase, but preincubation with 25 or 50 microM choline increased the ACh content to 272% of original levels, significantly greater than that of slices preincubated with either 0 or 10 microM choline. When tissues were subsequently incubated for 10 min with either KRB or 25 mM KCl, ACh release from slices preincubated with 50 microM choline was greater than from slices preincubated with 0, 10, or 25 microM choline. Incubation of slices with KRB did not alter the tissue content of ACh, but when tissues were incubated with 25 mM KCl, the ACh content of slices preincubated with 0 or 10 microM choline decreased significantly, whereas that of slices preincubated with 25 or 50 microM choline did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of low temperature on metabolism of rat liver slices and epididymal fat pads.

NASA Technical Reports Server (NTRS)

Hillyard, L. A.; Entenman, C.

1973-01-01

Study of low temperature effects on the metabolism of radioisotope-tagged glucose and palmitate in rat liver slices and epididymal fat pads. The obtained data suggest that the oxidative capacity of rat liver and adipose tissue is maintained at low temperatures to a greater degree than the synthetic capacity. It was concluded that sufficient energy can be produced at 17 C for maintenance of essential tissue functions by these two tissues but that the energy requirements may not be met at 7 C.

Metabolism of 2,2′,3,3′,6,6′-Hexachlorobiphenyl (PCB 136) Atropisomers in Tissue Slices from Phenobarbital or Dexamethasone-Induced Rats is Sex-Dependent

PubMed Central

Wu, Xianai; Kania-Korwel, Izabela; Chen, Hao; Stamou, Marianna; Dammanahalli, Karigowda J.; Duffel, Michael; Lein, Pamela J.; Lehmler, Hans-Joachim

2013-01-01

Chiral polychlorinated biphenyls (PCBs) such as PCB 136 enantioselectively sensitize the ryanodine receptor (RyR). In light of recent evidence that PCBs cause developmental neurotoxicity via RyR-dependent mechanisms, this suggests that enantioselective PCB metabolism may influence the developmental neurotoxicity of chiral PCBs. However, enantioselective disposition of PCBs has not been fully characterized.The effect of sex and cytochrome P450 (P450) enzyme induction on the enantioselective metabolism of PCB 136 was studied using liver tissue slices prepared from naïve control (CTL), phenobarbital (PB; CYP2B inducer) or dexamethasone (DEX; CYP3A inducer) pretreated adult Sprague-Dawley rats. PCB 136 metabolism was also examined in hippocampal slices derived from untreated rat pups.In liver tissue slices, hydroxylated PCB (OH-PCB) profiles depended on sex and inducer pretreatment, and OH-PCB levels followed the rank orders male > female and PB > DEX > CTL. In contrast, the enantiomeric enrichment of PCB 136 and its metabolites was independent of sex and inducer pretreatment. Only small amounts of PCB 136 partitioned into hippocampal tissue slices and no OH-PCB metabolites were detected.Our results suggest that enantioselective metabolism, sex and induction status of P450 enzymes in the liver may modulate the neurotoxic outcomes of developmental exposure to chiral PCBs. PMID:23581876

The preferred magnetic resonance imaging planes in quantifying visceral adipose tissue and evaluating cardiovascular risk.

PubMed

Liu, K H; Chan, Y L; Chan, J C N; Chan, W B; Kong, M O; Poon, M Y

2005-09-01

Magnetic Resonance Imaging (MRI) is a well-accepted non-invasive method in the quantification of visceral adipose tissue. However, a standard method of measurement has not yet been universally agreed. The objectives of the present study were 2-fold, firstly, to identify the imaging plane in the Chinese population which gives the best correlation with total visceral adipose tissue volume and cardiovascular risk factors; and secondly to compare the correlations between single-slice and multiple-slice approach with cardiovascular risk factors. Thirty-seven Chinese subjects with no known medical history underwent MRI examination for quantifying total visceral adipose tissue volume. The visceral adipose tissue area at five axial imaging levels within abdomen and pelvis were determined. All subjects had blood pressure measured and fasting blood taken for analysis of cardiovascular risk factors. Framingham risk score for each subject was calculated. The imaging plane at the level of 'lower costal margin' (LCM) in both men and women had the highest correlation with total visceral adipose tissue volume (r = 0.97 and 0.99 respectively). The visceral adipose tissue area at specific imaging levels showed higher correlations with various cardiovascular risk factors and Framingham risk score than total visceral adipose tissue volume. The visceral adipose tissue area at 'umbilicus' (UMB) level in men (r = 0.88) and LCM level in women (r = 0.70) showed the best correlation with Framingham risk score. The imaging plane at the level of LCM is preferred for reflecting total visceral adipose tissue volume in Chinese subjects. For investigating the association of cardiovascular risk with visceral adipose tissue in MRI-obesity research, the single-slice approach is superior to the multiple-slice approach, with the level of UMB in men and LCM in women as the preferred imaging planes.

Physiological, volatile, and SEM surface effects resulting from cutting and dipping treatments in cantaloupe.

PubMed

Beaulieu, John C; Ingber, Bruce F; Lea, Jeanne M

2011-09-01

Previous research examined sanitation treatments on cut cantaloupe tissue to deliver germicidal and food safety effects. However, an apparent compromise between volatile loss and treatment/sampling efficacy appeared. Subsequently, a physiological and volatile reassessment of thinly sliced tissue against cubes was performed in cantaloupe tissue. Thin sliced cantaloupe L* decreased 27.5%, 40.5%, and 52.9% in 3, 2, and 1 mm thickness, respectively, compared with cut cubes after 3 d. Overall color (C) decreased in freshly prepared cubes (2.4%) and slices (14.4%) that were washed in cold water. Surface area per unit volume (SA: vol) in slices was 4.1 times greater than typical cubes, as reflected by substantial water loss (20.4%, 9.5%, and 6.7% in 1, 2 and 3-mm slices, respectively) after 1 d at 5 °C. Rinsing cubes and thin-slices with 5 °C deionized water resulted in roughly 15% soluble solids loss. SEM indicated 65.4% reduced cell size in 1-d old thin slices, evidenced by excessive cell damage and desiccation compared with stored fresh-cut cubes. In thin-sliced tissue exposed 15 min to an open atmosphere (mimic sanitation treatments), total esters decreased 92.8% and 95.8%, respectively, after 1 and 3 d storage at 5 °C. Washing tissue provided a boundary layer that reduced short-term ester losses in slices and cubes. Excessive cutting, sanitation treatment regimes, and storage can radically alter the desirable volatile profile of cut cantaloupe. Reduction of tissue size to maximize food-safety sanitation efficacy or delivering items to a niche market will need substantial work to engineer equipment and develop protocols to insure that product quality and volatiles are not compromised. We have demonstrated that cutting method and sampling protocol are critically important when using volatiles as a means by which to assess or interpret stress response and ascribe fresh-cut quality. Reduction of tissue size to maximize food-safety sanitation efficacy (for example, thin slices) will need substantial work to engineer equipment and design protocols to insure product quality and volatile profiles are not compromised. Journal of Food Science © 2011 Institute of Food Technologists® No claim to original US government works.

Lipopolysaccharides do not alter metabolic disturbances in hippocampal slices of fetal guinea pigs after oxygen-glucose deprivation.

PubMed

Berger, R; Garnier, Y; Pfeiffer, D; Jensen, A

2000-10-01

The aim of the present study was to clarify whether endotoxins [lipopolysaccharides (LPS)] have a toxic effect on fetal brain tissue after cerebral ischemia, while excluding their effect on the cardiovascular system. Experiments were therefore performed on hippocampal slices prepared from mature fetal guinea pigs. In particular, we studied the influence of LPS on nitric oxide production, energy metabolism, and protein synthesis after oxygen-glucose deprivation (OGD). Incubating hippocampal slices in LPS (4 mg/L) for as long as 12 h did not alter cGMP tissue concentrations significantly. However, 10 min after OGD of 40-min duration, cGMP tissue concentrations were substantially increased in relation to controls, and this increase was almost completely blocked by the application of 100 microM N:(omega)-nitro-L-arginine, indicating that nitric oxide synthase was activated after OGD in fetal brain tissue. Again, LPS did not have any effect on cGMP tissue concentrations after OGD. Furthermore, addition of LPS altered neither protein synthesis nor energy metabolism measured 12 h after OGD. We therefore conclude that, apart from their well-known influence on the cardiovascular system, LPS do not alter metabolic disturbances in hippocampal slices of fetal guinea pigs 12 h after OGD. A direct toxic effect of LPS on immature brain tissue within this interval does not therefore seem to be very likely. However, delayed activation of LPS-sensitive pathways that may be involved in cell death, or damage limited to a small subgroup of cells such as oligodendrocyte progenitors, cannot be fully excluded.

Advancements in automated tissue segmentation pipeline for contrast-enhanced CT scans of adult and pediatric patients

NASA Astrophysics Data System (ADS)

Somasundaram, Elanchezhian; Kaufman, Robert; Brady, Samuel

2017-03-01

The development of a random forests machine learning technique is presented for fully-automated neck, chest, abdomen, and pelvis tissue segmentation of CT images using Trainable WEKA (Waikato Environment for Knowledge Analysis) Segmentation (TWS) plugin of FIJI (ImageJ, NIH). The use of a single classifier model to segment six tissue classes (lung, fat, muscle, solid organ, blood/contrast agent, bone) in the CT images is studied. An automated unbiased scheme to sample pixels from the training images and generate a balanced training dataset over the seven classes is also developed. Two independent training datasets are generated from a pool of 4 adult (>55 kg) and 3 pediatric patients (<=55 kg) with 7 manually contoured slices for each patient. Classifier training investigated 28 image filters comprising a total of 272 features. Highly correlated and insignificant features are eliminated using Correlated Feature Subset (CFS) selection with Best First Search (BFS) algorithms in WEKA. The 2 training models (from the 2 training datasets) had 74 and 71 input training features, respectively. The study also investigated the effect of varying the number of trees (25, 50, 100, and 200) in the random forest algorithm. The performance of the 2 classifier models are evaluated on inter-patient intra-slice, intrapatient inter-slice and inter-patient inter-slice test datasets. The Dice similarity coefficients (DSC) and confusion matrices are used to understand the performance of the classifiers across the tissue segments. The effect of number of features in the training input on the performance of the classifiers for tissue classes with less than optimal DSC values is also studied. The average DSC values for the two training models on the inter-patient intra-slice test data are: 0.98, 0.89, 0.87, 0.79, 0.68, and 0.84, for lung, fat, muscle, solid organ, blood/contrast agent, and bone, respectively. The study demonstrated that a robust segmentation accuracy for lung, muscle and fat tissue classes. For solid-organ, blood/contrast and bone, the performance of the segmentation pipeline improved significantly by using the advanced capabilities of WEKA. However, further improvements are needed to reduce the noise in the segmentation.

Multiband tissue classification for ultrasonic transmission tomography using spectral profile detection

NASA Astrophysics Data System (ADS)

Jeong, Jeong-Won; Kim, Tae-Seong; Shin, Dae-Chul; Do, Synho; Marmarelis, Vasilis Z.

2004-04-01

Recently it was shown that soft tissue can be differentiated with spectral unmixing and detection methods that utilize multi-band information obtained from a High-Resolution Ultrasonic Transmission Tomography (HUTT) system. In this study, we focus on tissue differentiation using the spectral target detection method based on Constrained Energy Minimization (CEM). We have developed a new tissue differentiation method called "CEM filter bank". Statistical inference on the output of each CEM filter of a filter bank is used to make a decision based on the maximum statistical significance rather than the magnitude of each CEM filter output. We validate this method through 3-D inter/intra-phantom soft tissue classification where target profiles obtained from an arbitrary single slice are used for differentiation in multiple tomographic slices. Also spectral coherence between target and object profiles of an identical tissue at different slices and phantoms is evaluated by conventional cross-correlation analysis. The performance of the proposed classifier is assessed using Receiver Operating Characteristic (ROC) analysis. Finally we apply our method to classify tiny structures inside a beef kidney such as Styrofoam balls (~1mm), chicken tissue (~5mm), and vessel-duct structures.

A microfluidic brain slice perfusion chamber for multisite recording using penetrating electrodes.

PubMed

Blake, Alexander J; Rodgers, Frank C; Bassuener, Anna; Hippensteel, Joseph A; Pearce, Thomas M; Pearce, Timothy R; Zarnowska, Ewa D; Pearce, Robert A; Williams, Justin C

2010-05-30

To analyze the spatiotemporal dynamics of network activity in a brain tissue slice, it is useful to record simultaneously from multiple locations. When obtained from laminar structures such as the hippocampus or neocortex, multisite recordings also yield information about subcellular current distributions via current source density analysis. Multisite probes developed for in vivo recordings could serve these purposes in vitro, allowing recordings to be obtained from brain slices at sites deeper within the tissue than currently available surface recording methods permit. However, existing recording chambers do not allow for the insertion of lamina-spanning probes that enter through the edges of brain slices. Here, we present a novel brain slice recording chamber design that accomplishes this goal. The device provides a stable microfluidic perfusion environment in which tissue health is optimized by superfusing both surfaces of the slice. Multichannel electrodes can be inserted parallel to the surface of the slice, at any depth relative to the surface. Access is also provided from above for the insertion of additional recording or stimulating electrodes. We illustrate the utility of this recording configuration by measuring current sources and sinks during theta burst stimuli that lead to the induction of long-term potentiation in hippocampal slices. (c) 2010 Elsevier B.V. All rights reserved.

Multi-slice ultrasound image calibration of an intelligent skin-marker for soft tissue artefact compensation.

PubMed

Masum, M A; Pickering, M R; Lambert, A J; Scarvell, J M; Smith, P N

2017-09-06

In this paper, a novel multi-slice ultrasound (US) image calibration of an intelligent skin-marker used for soft tissue artefact compensation is proposed to align and orient image slices in an exact H-shaped pattern. Multi-slice calibration is complex, however, in the proposed method, a phantom based visual alignment followed by transform parameters estimation greatly reduces the complexity and provides sufficient accuracy. In this approach, the Hough Transform (HT) is used to further enhance the image features which originate from the image feature enhancing elements integrated into the physical phantom model, thus reducing feature detection uncertainty. In this framework, slice by slice image alignment and calibration are carried out and this provides manual ease and convenience. Copyright © 2016 Elsevier Ltd. All rights reserved.

Correlation between in vivo and in vitro pulmonary responses to jet propulsion fuel-8 using precision-cut lung slices and a dynamic organ culture system.

PubMed

Hays, Allison M; Lantz, R Clark; Witten, Mark L

2003-01-01

In tissue slice models, interactions between the heterogeneous cell types comprising the lung parenchyma are maintained thus providing a controlled system for the study of pulmonary toxicology in vitro. However, validation of the model in vitro system must be affirmed. Previous reports, in in vivo systems, have demonstrated that Clara cells and alveolar type II cells are the targets following inhalation of JP-8 jet fuel. We have utilized the lung slice model to determine if cellular targets are similar following in vitro exposure to JP-8. Agar-filled adult rat lung explants were cored and precision cut, using the Brende/Vitron tissue slicer. Slices were cultured on titanium screens located as half-cylinders in cylindrical Teflon cradles that were loaded into standard scintillation vials and incubated at 37 degrees C. Slices were exposed to JP-8 jet fuel (0.5 mg/ml, 1.0 mg/ml, and 1.5 mg/ml in medium) for up to 24 hours. We determined ATP content using a luciferin-luciferase bioluminescent assay. No significant difference was found between the JP-8 jet fuel doses or time points, when compared to controls. Results were correlated with structural alterations following aerosol inhalation of JP-8. As a general observation, ultrastructural evaluation of alveolar type cells revealed an apparent increase in the number and size of surfactant secreting lamellar bodies that was JP-8 jet fuel-dose dependent. These results are similar to those observed following aerosol inhalation exposure. Thus, the lung tissue slice model appears to mimic in vivo effects of JP-8 and therefore is a useful model system for studying the mechanisms of lunginjury following JP-8 exposure.

Recording and Modulation of Epileptiform Activity in Rodent Brain Slices Coupled to Microelectrode Arrays.

PubMed

Panuccio, Gabriella; Colombi, Ilaria; Chiappalone, Michela

2018-05-15

Temporal lobe epilepsy (TLE) is the most common partial complex epileptic syndrome and the least responsive to medications. Deep brain stimulation (DBS) is a promising approach when pharmacological treatment fails or neurosurgery is not recommended. Acute brain slices coupled to microelectrode arrays (MEAs) represent a valuable tool to study neuronal network interactions and their modulation by electrical stimulation. As compared to conventional extracellular recording techniques, they provide the added advantages of a greater number of observation points and a known inter-electrode distance, which allow studying the propagation path and speed of electrophysiological signals. However, tissue oxygenation may be greatly impaired during MEA recording, requiring a high perfusion rate, which comes at the cost of decreased signal-to-noise ratio and higher oscillations in the experimental temperature. Electrical stimulation further stresses the brain tissue, making it difficult to pursue prolonged recording/stimulation epochs. Moreover, electrical modulation of brain slice activity needs to target specific structures/pathways within the brain slice, requiring that electrode mapping be easily and quickly performed live during the experiment. Here, we illustrate how to perform the recording and electrical modulation of 4-aminopyridine (4AP)-induced epileptiform activity in rodent brain slices using planar MEAs. We show that the brain tissue obtained from mice outperforms rat brain tissue and is thus better suited for MEA experiments. This protocol guarantees the generation and maintenance of a stable epileptiform pattern that faithfully reproduces the electrophysiological features observed with conventional field potential recording, persists for several hours, and outlasts sustained electrical stimulation for prolonged epochs. Tissue viability throughout the experiment is achieved thanks to the use of a small-volume custom recording chamber allowing for laminar flow and quick solution exchange even at low (1 mL/min) perfusion rates. Quick MEA mapping for real-time monitoring and selection of stimulating electrodes is performed by a custom graphic user interface (GUI).

Characterization and localization of /sup 3/H-arginine8-vasopressin binding to rat kidney and brain tissue

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

Dorsa, D.M.; Majumdar, L.A.; Petracca, F.M.

Anatomic, behavioral and pharmacologic evidence suggests that arginine8-vasopressin (AVP) serves as a CNS neurotransmitter or neuromodulator. AVP binding to membrane and tissue slice preparations from brain and kidney was characterized, and the anatomical distribution of these binding sites was examined. Conditions for the binding assay were optimized using kidney medullary tissue. Binding of /sup 3/H-AVP (S.A. . 30-51 Ci/mmol, NEN) to brain and kidney membranes and tissue slices was saturable, temperature dependent, linearly related to protein concentration (or number of tissue slices), reversible, and specific since the ability of cold AVP to displace /sup 3/H-AVP from binding was greater thanmore » oxytocin and other related peptide fragments. Autoradiographic localization of /sup 3/H-AVP binding was restricted to kidney medullary tissue. In brain tissue, /sup 3/H-AVP binding was found to occur in concentrated foci. Brainstem areas such as the nucleus tractus solitarius (NTS) showed a high density of AVP binding sites. Since local injections of AVP into the NTS have been shown to influence blood pressure, the present study presents the first anatomical evidence for the presence of AVP specific binding sites which might mediate this effect.« less

[Diagnostic values of bronchoscopy and multi-slice spiral CT for congenital dysplasia of the respiratory system in infants: a comparative study].

PubMed

Wang, Xing-Lu; Huang, Ying; Li, Qu-Bei; Dai, Ji-Hong

2013-09-01

To investigate and compare the diagnostic values of bronchoscopy and multi-slice spiral computed tomography (CT) for congenital dysplasia of the respiratory system in infants. Analysis was performed on the clinical data, bronchoscopic findings and multi-slice spiral CT findings of 319 infants (≤1 years old) who underwent bronchoscopy and/or multi-slice spiral CT and were diagnosed with congenital dysplasia of the respiratory system. A total of 476 cases of congenital dysplasia of the respiratory system were found in the 319 infants, including primary dysplasia of the respiratory system (392 cases) and compressive dysplasia of the respiratory system (84 cases). Of the 392 cases of primary dysplasia of the respiratory system, 225 (57.4%) were diagnosed by bronchoscopy versus 167 (42.6%) by multi-slice spiral CT. There were significant differences in etiological diagnosis between bronchoscopy and multi-slice spiral CT in infants with congenital dysplasia of the respiratory system (P<0.05). All 76 cases of primary dysplasia of the respiratory system caused by tracheobronchomalacia were diagnosed by bronchoscopy and all 17 cases of primary dysplasia of the respiratory system caused by lung tissue dysplasia were diagnosed by multi-slice spiral CT. Of the 84 cases of compressive dysplasia of the respiratory system, 74 cases were diagnosed by multi-slice spiral CT and only 10 cases were diagnosed by bronchoscopy. Compared with multi-slice spiral CT, bronchoscopy can detect primary dysplasia of the respiratory system more directly. Bronchoscopy is valuable in the confirmed diagnosis of tracheobronchomalacia. Multi-slice spiral CT has a higher diagnostic value for lung tissue dysplasia than bronchoscopy.

Mesenchymal stem cells and their conditioned medium improve integration of purified induced pluripotent stem cell-derived cardiomyocyte clusters into myocardial tissue.

PubMed

Rubach, Martin; Adelmann, Roland; Haustein, Moritz; Drey, Florian; Pfannkuche, Kurt; Xiao, Bing; Koester, Annette; Udink ten Cate, Floris E A; Choi, Yeong-Hoon; Neef, Klaus; Fatima, Azra; Hannes, Tobias; Pillekamp, Frank; Hescheler, Juergen; Šarić, Tomo; Brockmeier, Konrad; Khalil, Markus

2014-03-15

Induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) might become therapeutically relevant to regenerate myocardial damage. Purified iPS-CMs exhibit poor functional integration into myocardial tissue. The aim of this study was to investigate whether murine mesenchymal stem cells (MSCs) or their conditioned medium (MScond) improves the integration of murine iPS-CMs into myocardial tissue. Vital or nonvital embryonic murine ventricular tissue slices were cocultured with purified clusters of iPS-CMs in combination with murine embryonic fibroblasts (MEFs), MSCs, or MScond. Morphological integration was assessed by visual scoring and functional integration by isometric force and field potential measurements. We observed a moderate morphological integration of iPS-CM clusters into vital, but a poor integration into nonvital, slices. MEFs and MSCs but not MScond improved morphological integration of CMs into nonvital slices and enabled purified iPS-CMs to confer force. Coculture of vital slices with iPS-CMs and MEFs or MSCs resulted in an improved electrical integration. A comparable improvement of electrical coupling was achieved with the cell-free MScond, indicating that soluble factors secreted by MSCs were involved in electrical coupling. We conclude that cells such as MSCs support the engraftment and adhesion of CMs, and confer force to noncontractile tissue. Furthermore, soluble factors secreted by MSCs mediate electrical coupling of purified iPS-CM clusters to myocardial tissue. These data suggest that MSCs may increase the functional engraftment and therapeutic efficacy of transplanted iPS-CMs into infarcted myocardium.

Mesenchymal Stem Cells and Their Conditioned Medium Improve Integration of Purified Induced Pluripotent Stem Cell–Derived Cardiomyocyte Clusters into Myocardial Tissue

PubMed Central

Rubach, Martin; Adelmann, Roland; Haustein, Moritz; Drey, Florian; Pfannkuche, Kurt; Xiao, Bing; Koester, Annette; Udink ten Cate, Floris E.A.; Choi, Yeong-Hoon; Neef, Klaus; Fatima, Azra; Hannes, Tobias; Pillekamp, Frank; Hescheler, Juergen; Šarić, Tomo; Brockmeier, Konrad

2014-01-01

Induced pluripotent stem cell–derived cardiomyocytes (iPS-CMs) might become therapeutically relevant to regenerate myocardial damage. Purified iPS-CMs exhibit poor functional integration into myocardial tissue. The aim of this study was to investigate whether murine mesenchymal stem cells (MSCs) or their conditioned medium (MScond) improves the integration of murine iPS-CMs into myocardial tissue. Vital or nonvital embryonic murine ventricular tissue slices were cocultured with purified clusters of iPS-CMs in combination with murine embryonic fibroblasts (MEFs), MSCs, or MScond. Morphological integration was assessed by visual scoring and functional integration by isometric force and field potential measurements. We observed a moderate morphological integration of iPS-CM clusters into vital, but a poor integration into nonvital, slices. MEFs and MSCs but not MScond improved morphological integration of CMs into nonvital slices and enabled purified iPS-CMs to confer force. Coculture of vital slices with iPS-CMs and MEFs or MSCs resulted in an improved electrical integration. A comparable improvement of electrical coupling was achieved with the cell-free MScond, indicating that soluble factors secreted by MSCs were involved in electrical coupling. We conclude that cells such as MSCs support the engraftment and adhesion of CMs, and confer force to noncontractile tissue. Furthermore, soluble factors secreted by MSCs mediate electrical coupling of purified iPS-CM clusters to myocardial tissue. These data suggest that MSCs may increase the functional engraftment and therapeutic efficacy of transplanted iPS-CMs into infarcted myocardium. PMID:24219308

Organotypic slice cultures of human gastric and esophagogastric junction cancer.

PubMed

Koerfer, Justus; Kallendrusch, Sonja; Merz, Felicitas; Wittekind, Christian; Kubick, Christoph; Kassahun, Woubet T; Schumacher, Guido; Moebius, Christian; Gaßler, Nikolaus; Schopow, Nikolas; Geister, Daniela; Wiechmann, Volker; Weimann, Arved; Eckmann, Christian; Aigner, Achim; Bechmann, Ingo; Lordick, Florian

2016-07-01

Gastric and esophagogastric junction cancers are heterogeneous and aggressive tumors with an unpredictable response to cytotoxic treatment. New methods allowing for the analysis of drug resistance are needed. Here, we describe a novel technique by which human tumor specimens can be cultured ex vivo, preserving parts of the natural cancer microenvironment. Using a tissue chopper, fresh surgical tissue samples were cut in 400 μm slices and cultivated in 6-well plates for up to 6 days. The slices were processed for routine histopathology and immunohistochemistry. Cytokeratin stains (CK8, AE1/3) were applied for determining tumor cellularity, Ki-67 for proliferation, and cleaved caspase-3 staining for apoptosis. The slices were analyzed under naive conditions and following 2-4 days in vitro exposure to 5-FU and cisplatin. The slice culture technology allowed for a good preservation of tissue morphology and tumor cell integrity during the culture period. After chemotherapy exposure, a loss of tumor cellularity and an increase in apoptosis were observed. Drug sensitivity of the tumors could be assessed. Organotypic slice cultures of gastric and esophagogastric junction cancers were successfully established. Cytotoxic drug effects could be monitored. They may be used to examine mechanisms of drug resistance in human tissue and may provide a unique and powerful ex vivo platform for the prediction of treatment response. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Automated segmentations of skin, soft-tissue, and skeleton, from torso CT images

NASA Astrophysics Data System (ADS)

Zhou, Xiangrong; Hara, Takeshi; Fujita, Hiroshi; Yokoyama, Ryujiro; Kiryu, Takuji; Hoshi, Hiroaki

2004-05-01

We have been developing a computer-aided diagnosis (CAD) scheme for automatically recognizing human tissue and organ regions from high-resolution torso CT images. We show some initial results for extracting skin, soft-tissue and skeleton regions. 139 patient cases of torso CT images (male 92, female 47; age: 12-88) were used in this study. Each case was imaged with a common protocol (120kV/320mA) and covered the whole torso with isotopic spatial resolution of about 0.63 mm and density resolution of 12 bits. A gray-level thresholding based procedure was applied to separate the human body from background. The density and distance features to body surface were used to determine the skin, and separate soft-tissue from the others. A 3-D region growing based method was used to extract the skeleton. We applied this system to the 139 cases and found that the skin, soft-tissue and skeleton regions were recognized correctly for 93% of the patient cases. The accuracy of segmentation results was acceptable by evaluating the results slice by slice. This scheme will be included in CAD systems for detecting and diagnosing the abnormal lesions in multi-slice torso CT images.

Antibrowning and antimicrobial properties of sodium acid sulfate in apple slices.

PubMed

Fan, Xuetong; Sokorai, Kimberly J B; Liao, Ching-Hsing; Cooke, Peter; Zhang, Howard Q

2009-01-01

There are few available compounds that can both control browning and enhance microbial safety of fresh-cut fruits. In the present study, the antibrowning ability of sodium acid sulfate (SAS) on "Granny Smith" apple slices was first investigated in terms of optimum concentration and treatment time. In a separate experiment, the apple slices were treated with water or 3% of SAS, calcium ascorbate, citric acid, or acidified calcium sulfate for 5 min. Total plate count, color, firmness, and tissue damage were assessed during a 21-d storage at 4 degrees C. Results showed that the efficacy of SAS in inhibiting browning of apple slices increased with increasing concentration. A minimum 3% of SAS was needed to achieve 14 d of shelf life. Firmness was not significantly affected by SAS at 3% or lower concentrations. Antibrowning potential of SAS was similar for all treatment times ranging from 2 to 10 min. However, SAS caused some skin discoloration of apple slices. When cut surface of apple slices were stained with a fluorescein diacetate solution, tissue damage could be observed under a microscope even though visual damage was not evident. Among the antibrowning agents tested, SAS was the most effective in inhibiting browning and microbial growth for the first 14 d. Total plate count of samples treated with 3% SAS was significantly lower than those treated with calcium ascorbate, a commonly used antibrowning agent. Our results suggested that it is possible to use SAS to control browning while inhibiting the growth of microorganisms on the apple slices if the skin damage can be minimized. Practical Application: Fresh-cut apples have emerged as one of the popular products in restaurants, schools, and food service establishments as more consumers demand fresh, convenient, and nutritious foods. Processing of fresh-cut apples induces mechanical damage to the fruit and exposes apple tissue to air, resulting in the development of undesirable tissue browning. The fresh-cut industry currently uses antibrowning agents to prevent discoloration. However, the antibrowning solutions can become contaminated with human pathogens such as Listeria monocytogenes, and washing of apple slices with the contaminated solutions can result in the transfer of pathogens to the product. It would be ideal if an antibrowning compound prevented the proliferation of human pathogens in solutions and minimized the growth of pathogens during storage. The study was conducted to investigate antibrowning and antimicrobial properties of sodium acid sulfate (SAS) in comparison with other common antibrowning agents on Granny Smith apples. Results showed that among the antimicrobial agents we tested, SAS was the most effective in inhibiting browning and microbial growth for 14 d at 4 degrees C. However, SAS caused some skin discoloration of apple slices. Overall, SAS can potentially be used to inhibit tissue browning while reducing the microbial growth on apple slices. The information is useful for the fresh-cut produce industry to enhance microbial safety of fresh-cut apples while minimizing browning, thus increasing the consumption of the health benefiting fresh fruit.

Optimization of abdominal fat quantification on CT imaging through use of standardized anatomic space: A novel approach

PubMed Central

Tong, Yubing; Udupa, Jayaram K.; Torigian, Drew A.

2014-01-01

Purpose: The quantification of body fat plays an important role in the study of numerous diseases. It is common current practice to use the fat area at a single abdominal computed tomography (CT) slice as a marker of the body fat content in studying various disease processes. This paper sets out to answer three questions related to this issue which have not been addressed in the literature. At what single anatomic slice location do the areas of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) estimated from the slice correlate maximally with the corresponding fat volume measures? How does one ensure that the slices used for correlation calculation from different subjects are at the same anatomic location? Are there combinations of multiple slices (not necessarily contiguous) whose area sum correlates better with volume than does single slice area with volume? Methods: The authors propose a novel strategy for mapping slice locations to a standardized anatomic space so that same anatomic slice locations are identified in different subjects. The authors then study the volume-to-area correlations and determine where they become maximal. To address the third issue, the authors carry out similar correlation studies by utilizing two and three slices for calculating area sum. Results: Based on 50 abdominal CT data sets, the proposed mapping achieves significantly improved consistency of anatomic localization compared to current practice. Maximum correlations are achieved at different anatomic locations for SAT and VAT which are both different from the L4-L5 junction commonly utilized currently for single slice area estimation as a marker. Conclusions: The maximum area-to-volume correlation achieved is quite high, suggesting that it may be reasonable to estimate body fat by measuring the area of fat from a single anatomic slice at the site of maximum correlation and use this as a marker. The site of maximum correlation is not at L4-L5 as commonly assumed, but is more superiorly located at T12-L1 for SAT and at L3-L4 for VAT. Furthermore, the optimal anatomic locations for SAT and VAT estimation are not the same, contrary to common assumption. The proposed standardized space mapping achieves high consistency of anatomic localization by accurately managing nonlinearities in the relationships among landmarks. Multiple slices achieve greater improvement in correlation for VAT than for SAT. The optimal locations in the case of multiple slices are not contiguous. PMID:24877839

Optimization of abdominal fat quantification on CT imaging through use of standardized anatomic space: A novel approach

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

Tong, Yubing; Udupa, Jayaram K., E-mail: jay@mail.med.upenn.edu; Torigian, Drew A.

Purpose: The quantification of body fat plays an important role in the study of numerous diseases. It is common current practice to use the fat area at a single abdominal computed tomography (CT) slice as a marker of the body fat content in studying various disease processes. This paper sets out to answer three questions related to this issue which have not been addressed in the literature. At what single anatomic slice location do the areas of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) estimated from the slice correlate maximally with the corresponding fat volume measures? How doesmore » one ensure that the slices used for correlation calculation from different subjects are at the same anatomic location? Are there combinations of multiple slices (not necessarily contiguous) whose area sum correlates better with volume than does single slice area with volume? Methods: The authors propose a novel strategy for mapping slice locations to a standardized anatomic space so that same anatomic slice locations are identified in different subjects. The authors then study the volume-to-area correlations and determine where they become maximal. To address the third issue, the authors carry out similar correlation studies by utilizing two and three slices for calculating area sum. Results: Based on 50 abdominal CT data sets, the proposed mapping achieves significantly improved consistency of anatomic localization compared to current practice. Maximum correlations are achieved at different anatomic locations for SAT and VAT which are both different from the L4-L5 junction commonly utilized currently for single slice area estimation as a marker. Conclusions: The maximum area-to-volume correlation achieved is quite high, suggesting that it may be reasonable to estimate body fat by measuring the area of fat from a single anatomic slice at the site of maximum correlation and use this as a marker. The site of maximum correlation is not at L4-L5 as commonly assumed, but is more superiorly located at T12-L1 for SAT and at L3-L4 for VAT. Furthermore, the optimal anatomic locations for SAT and VAT estimation are not the same, contrary to common assumption. The proposed standardized space mapping achieves high consistency of anatomic localization by accurately managing nonlinearities in the relationships among landmarks. Multiple slices achieve greater improvement in correlation for VAT than for SAT. The optimal locations in the case of multiple slices are not contiguous.« less

Difference in Uptake of Tetrodotoxin and Saxitoxins into Liver Tissue Slices among Pufferfish, Boxfish and Porcupinefish

PubMed Central

Nagashima, Yuji; Ohta, Akira; Yin, Xianzhe; Ishizaki, Shoichiro; Doi, Hiroyuki; Ishibashi, Toshiaki

2018-01-01

Although pufferfish of the family Tetraodontidae contain high levels of tetrodotoxin (TTX) mainly in the liver, some species of pufferfish, boxfish of the family Ostraciidae, and porcupinefish of the family Diodontidae do not. To clarify the mechanisms, uptake of TTX and saxitoxins (STXs) into liver tissue slices of pufferfish, boxfish and porcupinefish was examined. Liver tissue slices of the pufferfish (toxic species Takifugu rubripes and non-toxic species Lagocephalus spadiceus, L. cheesemanii and Sphoeroides pachygaster) incubated with 50 µM TTX accumulated TTX (0.99–1.55 µg TTX/mg protein) after 8 h, regardless of the toxicity of the species. In contrast, in liver tissue slices of boxfish (Ostracion immaculatus) and porcupinefish (Diodon holocanthus, D. liturosus, D. hystrix and Chilomycterus reticulatus), TTX content did not increase with incubation time, and was about 0.1 µg TTX/mg protein. When liver tissue slices were incubated with 50 µM STXs for 8 h, the STXs content was <0.1 µg STXs/mg protein, irrespective of the fish species. These findings indicate that, like the toxic species of pufferfish T. rubripes, non-toxic species such as L. spadiceus, L. cheesemanii and S. pachygaster, potentially take up TTX into the liver, while non-toxic boxfish and porcupinefish do not take up either TTX or STXs. PMID:29316695

Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex

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

Ahn, C.S.; Tow, D.E.; Yu, C.C.

1994-03-01

It is widely recognized that the distribution of technetium-99m-labeled d,l-hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) in the brain is determined by the regional blood flow. However, other factors may affect this process including the metabolism of the brain tissue. To examine this possibility we studied the effects of metabolic alterations on {sup 99m}Tc-HMPAO uptake in rat brain cortex slices, with concurrent measurement of oxygen consumption (QO{sub 2}). {sup 99m}Tc-HMPAO uptake was determined by incubating slices of rat cerebral cortex at 37{degrees}C in Krebs-Ringer phosphate glucose medium containing {sup 99m}Tc-HMPAO with and without test substances. Differential gradients for {sup 99m}Tc activity betweenmore » the tissue and the suspending medium (T/M ratio) were derived from the equation T/M[{sup 99m}Tc] = counts per gram of tissue/counts per milliliter of medium. The QO{sub 2} of the brain slices was measured using a biological oxygen monitor equipped with a polarographic oxygen probe. Inhibitors affecting oxidative phosphorylation caused parallel suppression of the T/M ratio and QO{sub 2}. Agents that uncouple oxidation from phosphorylation increased the QO{sub 2} and decreased the T/M ratio. Incubation of slices at 22{degrees}C depressed the T/M ratio and QO{sub 2}. The presence of inhibitors of oxidative phosphorylation in the incubation medium increased the release of {sup 99m}Tc activity from slices that had been prelabeled with {sup 99m}Tc-HMPAO. These findings suggest that the altered metabolic status of the brain tissue modulates the kinetics and net accumulation of {sup 99m}Tc-HMPAO at the cellular level by either depressing uptake, increasing back-diffusion, or both. 33 refs., 4 figs., 3 tabs.« less

Combination of sodium chlorite and calcium propionate reduces enzymatic browning and microbial population of fresh-cut ‘Granny Smith’ apples

USDA-ARS?s Scientific Manuscript database

Tissue browning and microbial growth are the main concerns associated with fresh-cut apples. In this study, effects of sodium chlorite (SC) and calcium propionate (CP), individually and combined, on quality and microbial population of apple slices were investigated. ‘Granny Smith’ apple slices, dipp...

Three-dimensional slice cultures from murine fetal gut for investigations of the enteric nervous system.

PubMed

Metzger, Marco; Bareiss, Petra M; Nikolov, Ivan; Skutella, Thomas; Just, Lothar

2007-01-01

Three-dimensional intestinal cultures offer new possibilities for the examination of growth potential, analysis of time specific gene expression, and spatial cellular arrangement of enteric nervous system in an organotypical environment. We present an easy to produce in vitro model of the enteric nervous system for analysis and manipulation of cellular differentiation processes. Slice cultures of murine fetal colon were cultured on membrane inserts for up to 2 weeks without loss of autonomous contractility. After slice preparation, cultured tissue reorganized within the first days in vitro. Afterward, the culture possessed more than 35 cell layers, including high prismatic epithelial cells, smooth muscle cells, glial cells, and neurons analyzed by immunohistochemistry. The contraction frequency of intestinal slice culture could be modulated by the neurotransmitter serotonin and the sodium channel blocker tetrodotoxin. Coculture experiments with cultured neurospheres isolated from enhanced green fluorescent protein (eGFP) transgenic mice demonstrated that differentiating eGFP-positive neurons were integrated into the intestinal tissue culture. This slice culture model of enteric nervous system proved to be useful for studying cell-cell interactions, cellular signaling, and cell differentiation processes in a three-dimensional cell arrangement.

Dispersion analysis of collagen fiber networks in cervical tissue using optical coherence tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Gan, Yu; Yao, Wang; Myers, Kristin M.; Vink, Joy Y.; Wapner, Ronald J.; Hendon, Christine P.

2016-02-01

Understanding the human cervical collagen fiber network is critical to delineating the physiology of cervical remodeling during pregnancy. Previously, we presented our methodology to study the ultrastructure of collagen fibers over an entire field of transverse slices of human cervix tissue using optical coherence tomography. Here, we present a pixel-wise fiber orientation method to enable dispersion analysis on entire slices of human cervical tissues. We obtained en face images that were parallel to the surface. In each en face image, we masked the collagen fiber region based on signal noise ratio. Then, we extracted fiber orientations in each pixel using a weighted summation scheme and generated a pixel-wise directionality map within the entire region. The weight was determined by intensity variations between a pixel of interest and its neighboring pixels and their corresponding distances. We divided the directionality map into regions of 400 μm × 400 μm along radial direction in all four quadrants. In each region, we fit von-Mises distribution to fiber orientations of pixels with mode θ and dispersion b. We compared dispersions among regions and samples. Using IRB approved protocols, we obtained whole transverse slices of cervical tissue from pregnant (n = 2) and non-pregnant (n = 13) women. We observed higher dispersion in pregnant samples compared to non-pregnant samples and higher dispersions in patient's right/left zones than posterior/anterior zones within an axial slice. Future studies will analyze how collagen fiber dispersion patterns change from the internal to the external os.

A new technique for the rapid screening and selection of large pieces of tissue for ultrastructural evaluation.

PubMed

Dalley, B K; Seliger, W G

1980-05-01

A simple and rapid technique is described for the screening of Epon embedded organ slices for the location, isolation, and removal of small specific sites for ultrastructural study with the transmission electron microscope. This procedure consists of perfusion fixation followed by making 1 to 21/2 mm thick slices of relatively large pieces of the organs, control of the degree and evenness of the osmium staining by addition of 3% sodium iodate, and infiltration with a fluorescent dye prior to embedment in Epon. Tissue slices are embedded in wafer-shaped blocks, generally with several slices in one "wafer", and are examined in a controlled manner using a rapid form of serial surface polishing. Each level of the polished wafer is examined using an epi-illuminated fluorescence microscope, and selected sites are chosen at each level for ultrastructural study. Methods are also described for marking each selected site using a conventional slide marker, and for the removal of the selected site in the form of a small disc of Epon, after which the Epon wafer can be further serially polished and the examination continued. Areas to be thin-sectioned are removed using a core drill mounted on a model-maker's drill press. The technique is simple, does not require the destruction of remaining tissues to evaluate more critically a single small site, allows for the easy maintenance of tissue orientation, and the most time-consuming portions of the technique can be quickly taught to a person with no previous histological training.

Localized Drug Application and Sub-Second Voltammetric Dopamine Release Measurements in a Brain Slice Perfusion Device

PubMed Central

2015-01-01

The use of fast scan cyclic voltammetry (FSCV) to measure the release and uptake of dopamine (DA) as well as other biogenic molecules in viable brain tissue slices has gained popularity over the last 2 decades. Brain slices have the advantage of maintaining the functional three-dimensional architecture of the neuronal network while also allowing researchers to obtain multiple sets of measurements from a single animal. In this work, we describe a simple, easy-to-fabricate perfusion device designed to focally deliver pharmacological agents to brain slices. The device incorporates a microfluidic channel that runs under the perfusion bath and a microcapillary that supplies fluid from this channel up to the slice. We measured electrically evoked DA release in brain slices before and after the administration of two dopaminergic stimulants, cocaine and GBR-12909. Measurements were collected at two locations, one directly over and the other 500 μm away from the capillary opening. Using this approach, the controlled delivery of drugs to a confined region of the brain slice and the application of this chamber to FSCV measurements, were demonstrated. Moreover, the consumption of drugs was reduced to tens of microliters, which is thousands of times less than traditional perfusion methods. We expect that this simply fabricated device will be useful in providing spatially resolved delivery of drugs with minimum consumption for voltammetric and electrophysiological studies of a variety of biological tissues both in vitro and ex vivo. PMID:24734992

Discovery of Hyperpolarized Molecular Imaging Biomarkers in a Novel Prostate Tissue Slice Culture Model

DTIC Science & Technology

2013-06-01

start of tissue 2D culture , and 3 and 20 hours post culturing of the TSC’s in the 3D bioreactor (left) and corresponding representative tissue... culture tissue slice 13P spectrum obtained after 20 hours in the 5mm 3D MR compatible tissue culture bioreactor . 5 TSC’s with ≈ 90% viability...hours (≈98%) of being in 3D culture within the MR compatible bioreactor . • We demonstrated that the increased flux from pyruvate to lactate in the

Standardized anatomic space for abdominal fat quantification

NASA Astrophysics Data System (ADS)

Tong, Yubing; Udupa, Jayaram K.; Torigian, Drew A.

2014-03-01

The ability to accurately measure subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from images is important for improved assessment and management of patients with various conditions such as obesity, diabetes mellitus, obstructive sleep apnea, cardiovascular disease, kidney disease, and degenerative disease. Although imaging and analysis methods to measure the volume of these tissue components have been developed [1, 2], in clinical practice, an estimate of the amount of fat is obtained from just one transverse abdominal CT slice typically acquired at the level of the L4-L5 vertebrae for various reasons including decreased radiation exposure and cost [3-5]. It is generally assumed that such an estimate reliably depicts the burden of fat in the body. This paper sets out to answer two questions related to this issue which have not been addressed in the literature. How does one ensure that the slices used for correlation calculation from different subjects are at the same anatomic location? At what anatomic location do the volumes of SAT and VAT correlate maximally with the corresponding single-slice area measures? To answer these questions, we propose two approaches for slice localization: linear mapping and non-linear mapping which is a novel learning based strategy for mapping slice locations to a standardized anatomic space so that same anatomic slice locations are identified in different subjects. We then study the volume-to-area correlations and determine where they become maximal. We demonstrate on 50 abdominal CT data sets that this mapping achieves significantly improved consistency of anatomic localization compared to current practice. Our results also indicate that maximum correlations are achieved at different anatomic locations for SAT and VAT which are both different from the L4-L5 junction commonly utilized.

Quantitative CT imaging for adipose tissue analysis in mouse model of obesity

NASA Astrophysics Data System (ADS)

Marchadier, A.; Vidal, C.; Tafani, J.-P.; Ordureau, S.; Lédée, R.; Léger, C.

2011-03-01

In obese humans CT imaging is a validated method for follow up studies of adipose tissue distribution and quantification of visceral and subcutaneous fat. Equivalent methods in murine models of obesity are still lacking. Current small animal micro-CT involves long-term X-ray exposure precluding longitudinal studies. We have overcome this limitation by using a human medical CT which allows very fast 3D imaging (2 sec) and minimal radiation exposure. This work presents novel methods fitted to in vivo investigations of mice model of obesity, allowing (i) automated detection of adipose tissue in abdominal regions of interest, (ii) quantification of visceral and subcutaneous fat. For each mouse, 1000 slices (100μm thickness, 160 μm resolution) were acquired in 2 sec using a Toshiba medical CT (135 kV, 400mAs). A Gaussian mixture model of the Hounsfield curve of 2D slices was computed with the Expectation Maximization algorithm. Identification of each Gaussian part allowed the automatic classification of adipose tissue voxels. The abdominal region of interest (umbilical) was automatically detected as the slice showing the highest ratio of the Gaussian proportion between adipose and lean tissues. Segmentation of visceral and subcutaneous fat compartments was achieved with 2D 1/2 level set methods. Our results show that the application of human clinical CT to mice is a promising approach for the study of obesity, allowing valuable comparison between species using the same imaging materials and software analysis.

Optimized heterologous transfection of viable adult organotypic brain slices using an enhanced gene gun

PubMed Central

2013-01-01

Background Organotypic brain slices (OTBS) are an excellent experimental compromise between the facility of working with cell cultures and the biological relevance of using animal models where anatomical, morphological, and cellular function of specific brain regions can be maintained. The biological characteristics of OTBS can subsequently be examined under well-defined conditions. They do, however, have a number of limitations; most brain slices are derived from neonatal animals, as it is difficult to properly prepare and maintain adult OTBS. There are ample problems with tissue integrity as OTBS are delicate and frequently become damaged during the preparative stages. Notwithstanding these obstacles, the introduced exogenous proteins into both neuronal cells, and cells imbedded within tissues, have been consistently difficult to achieve. Results Following the ex vivo extraction of adult mouse brains, mounted inside a medium-agarose matrix, we have exploited a precise slicing procedure using a custom built vibroslicer. To transfect these slices we used an improved biolistic transfection method using a custom made low-pressure barrel and novel DNA-coated nanoparticles (40 nm), which are drastically smaller than traditional microparticles. These nanoparticles also minimize tissue damage as seen by a significant reduction in lactate dehydrogenase activity as well as propidium iodide (PI) and dUTP labelling compared to larger traditional gold particles used on these OTBS. Furthermore, following EYFP exogene delivery by gene gun, the 40 nm treated OTBS displayed a significantly larger number of viable NeuN and EYFP positive cells. These OTBS expressed the exogenous proteins for many weeks. Conclusions Our described methodology of producing OTBS, which results in better reproducibility with less tissue damage, permits the exploitation of mature fully formed adult brains for advanced neurobiological studies. The novel 40 nm particles are ideal for the viable biolistic transfection of OTBS by reducing tissue stress while maintaining long term exogene expression. PMID:24354851

Scaffold-free Prevascularized Microtissue Spheroids for Pulp Regeneration

PubMed Central

Dissanayaka, W.L.; Zhu, L.; Hargreaves, K.M.; Jin, L.; Zhang, C.

2014-01-01

Creating an optimal microenvironment that mimics the extracellular matrix (ECM) of natural pulp and securing an adequate blood supply for the survival of cell transplants are major hurdles that need to be overcome in dental pulp regeneration. However, many currently available scaffolds fail to mimic essential functions of natural ECM. The present study investigated a novel approach involving the use of scaffold-free microtissue spheroids of dental pulp stem cells (DPSCs) prevascularized by human umbilical vein endothelial cells (HUVECs) in pulp regeneration. In vitro-fabricated microtissue spheroids were inserted into the canal space of tooth-root slices and were implanted subcutaneously into immunodeficient mice. Histological examination revealed that, after four-week implantation, tooth-root slices containing microtissue spheroids resulted in well-vascularized and cellular pulp-like tissues, compared with empty tooth-root slices, which were filled with only subcutaneous fat tissue. Immunohistochemical staining indicated that the tissue found in the tooth-root slices was of human origin, as characterized by the expression of human mitochondria, and contained odontoblast-like cells organized along the dentin, as assessed by immunostaining for nestin and dentin sialoprotein (DSP). Vascular structures formed by HUVECs in vitro were successfully anastomosed with the host vasculature upon transplantation in vivo, as shown by immunostaining for human CD31. Collectively, these findings demonstrate that prevascularized, scaffold-free, microtissue spheroids can successfully regenerate vascular dental pulp-like tissue and also highlight the significance of the microtissue microenvironment as an optimal environment for successful pulp-regeneration strategies. PMID:25201919

SU-C-207B-03: A Geometrical Constrained Chan-Vese Based Tumor Segmentation Scheme for PET

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

Chen, L; Zhou, Z; Wang, J

Purpose: Accurate segmentation of tumor in PET is challenging when part of tumor is connected with normal organs/tissues with no difference in intensity. Conventional segmentation methods, such as thresholding or region growing, cannot generate satisfactory results in this case. We proposed a geometrical constrained Chan-Vese based scheme to segment tumor in PET for this special case by considering the similarity between two adjacent slices. Methods: The proposed scheme performs segmentation in a slice-by-slice fashion where an accurate segmentation of one slice is used as the guidance for segmentation of rest slices. For a slice that the tumor is not directlymore » connected to organs/tissues with similar intensity values, a conventional clustering-based segmentation method under user’s guidance is used to obtain an exact tumor contour. This is set as the initial contour and the Chan-Vese algorithm is applied for segmenting the tumor in the next adjacent slice by adding constraints of tumor size, position and shape information. This procedure is repeated until the last slice of PET containing tumor. The proposed geometrical constrained Chan-Vese based algorithm was implemented in Matlab and its performance was tested on several cervical cancer patients where cervix and bladder are connected with similar activity values. The positive predictive values (PPV) are calculated to characterize the segmentation accuracy of the proposed scheme. Results: Tumors were accurately segmented by the proposed method even when they are connected with bladder in the image with no difference in intensity. The average PPVs were 0.9571±0.0355 and 0.9894±0.0271 for 17 slices and 11 slices of PET from two patients, respectively. Conclusion: We have developed a new scheme to segment tumor in PET images for the special case that the tumor is quite similar to or connected to normal organs/tissues in the image. The proposed scheme can provide a reliable way for segmenting tumors.« less

Brain Slice Staining and Preparation for Three-Dimensional Super-Resolution Microscopy

PubMed Central

German, Christopher L.; Gudheti, Manasa V.; Fleckenstein, Annette E.; Jorgensen, Erik M.

2018-01-01

Localization microscopy techniques – such as photoactivation localization microscopy (PALM), fluorescent PALM (FPALM), ground state depletion (GSD), and stochastic optical reconstruction microscopy (STORM) – provide the highest precision for single molecule localization currently available. However, localization microscopy has been largely limited to cell cultures due to the difficulties that arise in imaging thicker tissue sections. Sample fixation and antibody staining, background fluorescence, fluorophore photoinstability, light scattering in thick sections, and sample movement create significant challenges for imaging intact tissue. We have developed a sample preparation and image acquisition protocol to address these challenges in rat brain slices. The sample preparation combined multiple fixation steps, saponin permeabilization, and tissue clarification. Together, these preserve intracellular structures, promote antibody penetration, reduce background fluorescence and light scattering, and allow acquisition of images deep in a 30 μm thick slice. Image acquisition challenges were resolved by overlaying samples with a permeable agarose pad and custom-built stainless steel imaging adapter, and sealing the imaging chamber. This approach kept slices flat, immobile, bathed in imaging buffer, and prevented buffer oxidation during imaging. Using this protocol, we consistently obtained single molecule localizations of synaptic vesicle and active zone proteins in three-dimensions within individual synaptic terminals of the striatum in rat brain slices. These techniques may be easily adapted to the preparation and imaging of other tissues, substantially broadening the application of super-resolution imaging. PMID:28924666

Redox regulation of epithelial sodium channels examined in alveolar type 1 and 2 cells patch-clamped in lung slice tissue.

PubMed

Helms, My N; Jain, Lucky; Self, Julie L; Eaton, Douglas C

2008-08-15

The alveolar surface of the lung is lined by alveolar type 1 (AT1) and type 2 (AT2) cells. Using single channel patch clamp analysis in lung slice preparations, we are able to uniquely study AT1 and AT2 cells separately from intact lung. We report for the first time the Na+ transport properties of type 2 cells accessed in live lung tissue (as we have done in type 1 cells). Type 2 cells in lung tissue slices express both highly selective cation and nonselective cation channels with average conductances of 8.8 +/- 3.2 and 22.5 +/- 6.3 picosiemens, respectively. Anion channels with 10-picosiemen conductance are also present in the apical membrane of type 2 cells. Our lung slice studies importantly verify the use of cultured cell model systems commonly used in lung epithelial sodium channel (ENaC) studies. Furthermore, we identify novel functional differences between the cells that make up the alveolar epithelium. One important difference is that exposure to the nitric oxide (NO) donor, PAPA-NONOate (1.5 microm), significantly decreases average ENaC NPo in type 2 cells (from 1.38 +/- 0.26 to 0.82 +/- 0.16; p < 0.05 and n = 18) but failed to alter ENaC activity in alveolar type 1 cells. Elevating endogenous superoxide (O2.) levels with Ethiolat, a superoxide dismutase inhibitor, prevented NO inhibition of ENaC activity in type 2 cells, supporting the novel hypothesis that O2. and NO signaling plays an important role in maintaining lung fluid balance.

Synchrotron X-ray microtransections: a non invasive approach for epileptic seizures arising from eloquent cortical areas

PubMed Central

Pouyatos, B.; Nemoz, C.; Chabrol, T.; Potez, M.; Bräuer, E.; Renaud, L.; Pernet-Gallay, K.; Estève, F.; David, O.; Kahane, P.; Laissue, J. A.; Depaulis, A.; Serduc, R.

2016-01-01

Synchrotron-generated X-ray (SRX) microbeams deposit high radiation doses to submillimetric targets whilst minimizing irradiation of neighboring healthy tissue. We developed a new radiosurgical method which demonstrably transects cortical brain tissue without affecting adjacent regions. We made such image-guided SRX microtransections in the left somatosensory cortex in a rat model of generalized epilepsy using high radiation doses (820 Gy) in thin (200 μm) parallel slices of tissue. This procedure, targeting the brain volume from which seizures arose, altered the abnormal neuronal activities for at least 9 weeks, as evidenced by a decrease of seizure power and coherence between tissue slices in comparison to the contralateral cortex. The brain tissue located between transections stayed histologically normal, while the irradiated micro-slices remained devoid of myelin and neurons two months after irradiation. This pre-clinical proof of concept highlights the translational potential of non-invasive SRX transections for treating epilepsies that are not eligible for resective surgery. PMID:27264273

Synchrotron X-ray microtransections: a non invasive approach for epileptic seizures arising from eloquent cortical areas

NASA Astrophysics Data System (ADS)

Pouyatos, B.; Nemoz, C.; Chabrol, T.; Potez, M.; Bräuer, E.; Renaud, L.; Pernet-Gallay, K.; Estève, F.; David, O.; Kahane, P.; Laissue, J. A.; Depaulis, A.; Serduc, R.

2016-06-01

Synchrotron-generated X-ray (SRX) microbeams deposit high radiation doses to submillimetric targets whilst minimizing irradiation of neighboring healthy tissue. We developed a new radiosurgical method which demonstrably transects cortical brain tissue without affecting adjacent regions. We made such image-guided SRX microtransections in the left somatosensory cortex in a rat model of generalized epilepsy using high radiation doses (820 Gy) in thin (200 μm) parallel slices of tissue. This procedure, targeting the brain volume from which seizures arose, altered the abnormal neuronal activities for at least 9 weeks, as evidenced by a decrease of seizure power and coherence between tissue slices in comparison to the contralateral cortex. The brain tissue located between transections stayed histologically normal, while the irradiated micro-slices remained devoid of myelin and neurons two months after irradiation. This pre-clinical proof of concept highlights the translational potential of non-invasive SRX transections for treating epilepsies that are not eligible for resective surgery.

Best single-slice location to measure visceral adipose tissue on paediatric CT scans and the relationship between anthropometric measurements, gender and VAT volume in children.

PubMed

O'Connor, Michelle; Ryan, John; Foley, Shane

2015-10-01

Visceral adipose tissue (VAT) is a significant risk factor for obesity-related metabolic diseases. This study investigates (1) the best single CT slice location for predicting total abdominal VAT volume in paediatrics and (2) the relationship between waist circumference (WC), sagittal diameter (SD), gender and VAT volume. A random sample of 130 paediatric abdomen CT scans, stratified according to age and gender, was collected. Three readers measured VAT area at each intervertebral level between T12 and S1 using ImageJ analysis (National Institute of Health, Bethesda, MD) software by thresholding -190 to -30 HU and manually segmenting VAT. Single-slice VAT measurements were correlated with total VAT volume to identify the most representative slice. WC and SD were measured at L3-L4 and L4-L5 slices, respectively. Regression analysis was used to evaluate WC, SD and gender as VAT volume predictors. Interviewer and intraviewer reliability were excellent (intraclass correlation coefficient = 0.99). Although VAT measured at multiple slices correlated strongly with abdominal VAT, only one slice in females at L2-L3 and two slices in males at L1-L2 and L5-S1 were strongly correlated across all age groups. Linear regression analysis showed that WC was strongly correlated with VAT volume (beta = 0.970, p < 0.001). Single-slice VAT measurements are highly reproducible. Measurements performed at L2-L3 in females and L1-L2 or L5-S1 in males were most representative of VAT. WC is indicative of VAT. VAT should be measured at L2-L3 in female children and at either L1-L2 or L5-S1 in males. WC is a strong indicator of VAT in children.

ARGON, XENON, HYDROGEN, AND THE OXYGEN CONSUMPTION AND GLYCOLYSIS OF MOUSE TISSUE SLICES

PubMed Central

South, Frank E.; Cook, Sherburne F.

1954-01-01

The effects of xenon, argon, and hydrogen on the aerobic and anaerobic metabolism of mouse liver, brain, and sarcoma slices have been investigated. Xenon was found to alter the rates of metabolism of these tissues in a manner almost identical with helium. The gas increased the rate of oxygen consumption in all three tissues and significantly depressed that of anaerobic glycolysis in brain and liver. The depression of glycolysis in sarcoma was less pronounced and not highly significant. Although both the magnitude and statistical significance of the effects observed with argon were much smaller, there was a seeming adherence to the general pattern established by xenon and helium. Hydrogen while remaining essentially ineffective insofar as oxygen uptake was concerned, depressed glycolysis in both liver and brain slices but did not significantly affect sarcoma slices. The following points are stressed in the Discussion: (1) the magnitude and direction of effects exerted by helium, argon, xenon, hydrogen, and nitrogen do not conform with the relative values of molecular weight, density, and solubility of these gases; (2) the effect of these gases on tissue metabolism does not necessarily parallel that exerted upon the whole organism. PMID:13118104

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

Xiao, Z; Reyhan, M; Huang, Q

Purpose: The calibration of the Hounsfield units (HU) to relative proton stopping powers (RSP) is a crucial component in assuring the accurate delivery of proton therapy dose distributions to patients. The purpose of this work is to assess the uncertainty of CT calibration considering the impact of CT slice thickness, position of the plug within the phantom and phantom sizes. Methods: Stoichiometric calibration method was employed to develop the CT calibration curve. Gammex 467 tissue characterization phantom was scanned in Tomotherapy Cheese phantom and Gammex 451 phantom by using a GE CT scanner. Each plug was individually inserted into themore » same position of inner and outer ring of phantoms at each time, respectively. 1.25 mm and 2.5 mm slice thickness were used. Other parameters were same. Results: HU of selected human tissues were calculated based on fitted coefficient (Kph, Kcoh and KKN), and RSP were calculated according to the Bethe-Bloch equation. The calibration curve was obtained by fitting cheese phantom data with 1.25 mm thickness. There is no significant difference if the slice thickness, phantom size, position of plug changed in soft tissue. For boney structure, RSP increases up to 1% if the phantom size and the position of plug changed but keep the slice thickness the same. However, if the slice thickness varied from the one in the calibration curve, 0.5%–3% deviation would be expected depending on the plug position. The Inner position shows the obvious deviation (averagely about 2.5%). Conclusion: RSP shows a clinical insignificant deviation in soft tissue region. Special attention may be required when using a different slice thickness from the calibration curve for boney structure. It is clinically practical to address 3% deviation due to different thickness in the definition of clinical margins.« less

Pulmonary fatty acid synthesis. I. Mitochondrial acetyl transfer by rat lung in vitro.

PubMed

Evans, R M; Scholz, R W

1977-04-01

Incorporation of tritiated water into fatty acids by rat adipose tissue and lung tissue slices incubated with 5 mM glucose indicated a level of fatty acid synthesis in rat lung approximately 15% that observed in adipose tissue in vitro. (-)-Hydroxycitrate, and inhibitor of ATP citrate lyase, markedly reduced tritiated water incorporation into fatty acids by lung tissue slices. The effects of (-)-hydroxycitrate and n-butymalonate on the incorporation of 14C-labeled glucose, pyruvate, acetate, and citrate suggested that citrate is a major acetyl carrier for de novo fatty acid synthesis in lung tissue. Alternative mechanisms to citrate as an acetyl carrier were also considered. Lung mitochondrial preparations formed significant levels of acetylcarnitine in the presence of pyruvate and carnitine. However, the effect of carnitine on the incorporation of 14C-labeled glucose, pyruvate, acetate, and citrate into fatty acids by lung tissue slices indicated that acetylcarnitine may not be a significant acetyl carrier for fatty acid synthesis but may serve as an acetyl "buffer" in the control of mitochondrial acetyl-CoA levels. Additionally, it appears unlikely that either acetylaspartate or acetoacetate are of major importance in acetyl transfer in lung tissue.

Body composition estimation from selected slices: equations computed from a new semi-automatic thresholding method developed on whole-body CT scans

PubMed Central

Villa, Chiara; Brůžek, Jaroslav

2017-01-01

Background Estimating volumes and masses of total body components is important for the study and treatment monitoring of nutrition and nutrition-related disorders, cancer, joint replacement, energy-expenditure and exercise physiology. While several equations have been offered for estimating total body components from MRI slices, no reliable and tested method exists for CT scans. For the first time, body composition data was derived from 41 high-resolution whole-body CT scans. From these data, we defined equations for estimating volumes and masses of total body AT and LT from corresponding tissue areas measured in selected CT scan slices. Methods We present a new semi-automatic approach to defining the density cutoff between adipose tissue (AT) and lean tissue (LT) in such material. An intra-class correlation coefficient (ICC) was used to validate the method. The equations for estimating the whole-body composition volume and mass from areas measured in selected slices were modeled with ordinary least squares (OLS) linear regressions and support vector machine regression (SVMR). Results and Discussion The best predictive equation for total body AT volume was based on the AT area of a single slice located between the 4th and 5th lumbar vertebrae (L4-L5) and produced lower prediction errors (|PE| = 1.86 liters, %PE = 8.77) than previous equations also based on CT scans. The LT area of the mid-thigh provided the lowest prediction errors (|PE| = 2.52 liters, %PE = 7.08) for estimating whole-body LT volume. We also present equations to predict total body AT and LT masses from a slice located at L4-L5 that resulted in reduced error compared with the previously published equations based on CT scans. The multislice SVMR predictor gave the theoretical upper limit for prediction precision of volumes and cross-validated the results. PMID:28533960

Body composition estimation from selected slices: equations computed from a new semi-automatic thresholding method developed on whole-body CT scans.

PubMed

Lacoste Jeanson, Alizé; Dupej, Ján; Villa, Chiara; Brůžek, Jaroslav

2017-01-01

Estimating volumes and masses of total body components is important for the study and treatment monitoring of nutrition and nutrition-related disorders, cancer, joint replacement, energy-expenditure and exercise physiology. While several equations have been offered for estimating total body components from MRI slices, no reliable and tested method exists for CT scans. For the first time, body composition data was derived from 41 high-resolution whole-body CT scans. From these data, we defined equations for estimating volumes and masses of total body AT and LT from corresponding tissue areas measured in selected CT scan slices. We present a new semi-automatic approach to defining the density cutoff between adipose tissue (AT) and lean tissue (LT) in such material. An intra-class correlation coefficient (ICC) was used to validate the method. The equations for estimating the whole-body composition volume and mass from areas measured in selected slices were modeled with ordinary least squares (OLS) linear regressions and support vector machine regression (SVMR). The best predictive equation for total body AT volume was based on the AT area of a single slice located between the 4th and 5th lumbar vertebrae (L4-L5) and produced lower prediction errors (|PE| = 1.86 liters, %PE = 8.77) than previous equations also based on CT scans. The LT area of the mid-thigh provided the lowest prediction errors (|PE| = 2.52 liters, %PE = 7.08) for estimating whole-body LT volume. We also present equations to predict total body AT and LT masses from a slice located at L4-L5 that resulted in reduced error compared with the previously published equations based on CT scans. The multislice SVMR predictor gave the theoretical upper limit for prediction precision of volumes and cross-validated the results.

OXIDATION OF POLYCHLORINATED BIPHENYLS BY LIVER TISSUE SLICES FROM PHENOBARBITAL-PRETREATED MICE IS CONGENER-SPECIFIC AND ATROPSELECTIVE

PubMed Central

Wu, Xianai; Duffel, Michael; Lehmler, Hans-Joachim

2013-01-01

Mouse models are powerful tools to study the developmental neurotoxicity of polychlorinated biphenyls (PCBs); however, studies of the oxidation of chiral PCB congeners to potentially neurotoxic hydroxylated metabolites (OH-PCBs) in mice have not been reported. Here we investigate the atropselective oxidation of chiral PCB 91 (2,2',3,4',6-pentachlorobiphenyl), PCB 95 (2,2',3,5',6-pentachlorobiphenyl), PCB 132 (2,2',3,3',4,6'-hexachlorobiphenyl), PCB 136 (2,2',3,3',6,6'-hexachlorobiphenyl) and PCB 149 (2,2',3,4',5',6-hexachlorobiphenyl) to OH-PCBs in liver tissue slices prepared from female mice. The metabolite profile of PCB 136 typically followed the rank order 5-OH-PCB > 4-OH-PCB > 4,5-OH-PCB, and metabolite levels increased with PCB concentration and incubation time. A similar OH-PCB profile was observed with the other PCB congeners, with 5-OH-PCB:4-OH-PCB ratios ranging from 2 to 12. More 5-OH-PCB 136 was formed in liver tissue slices obtained from animals pretreated with phenobarbital (P450 2B inducer) or, to a lesser extent, dexamethasone (P450 2B and 3A enzyme inducer) compared to tissue slices prepared from vehicle-pretreated animals. The apparent rate of 5-OH-PCBs formation followed the approximate rank order PCB 149 > PCB 91 > PCB 132 ~ PCB 136 > PCB 95. Atropselective gas chromatography revealed a congener-specific atropisomeric enrichment of major OH-PCB metabolites. Comparison of our results with published OH-PCB patterns and chiral signatures (i.e., the direction and extent of the atropisomeric enrichment) from rat liver microsomal revealed drastic differences between both species, especially following induction of P450 2B enzymes. These species differences in the metabolism of chiral PCBs should be considered in developmental neurotoxicity studies of PCBs. PMID:24107130

NTP and PCr responses to hypoxia by hypothermic and normothermic respiring, superfused, neonatal rat cerebrocortical slices: an NMR spectroscopy study at 14.1 Tesla.

PubMed

Litt, L; Hirai, K; Basus, V J; James, T L

2003-01-01

Although mechanisms of hypothermic neuroprotection during oxygen deprivation have long been investigated, further characterizations of various molecular mechanisms are appropriate. Anticipating future studies of hypothermia and hypoxia/ischemia, we investigated the extent to which our ex vivo, NMR-based, superfused brain slice model might be helpful. (Slices are approximately 350 microm thick, with 18 slices per 8 mm NMR tube.) 31P NMR spectroscopic measurements were made of hypothermia-induced changes in high energy phosphates, while simultaneously monitoring and controlling tissue temperature, using 1H NMR, the high spectroscopic resolution available at 14.1 Tesla (600 MHz for protons), and a recently published protocol. NTP and PCr concentrations in healthy, well-oxygenated slices decreased to (55 +/- 15)% and (66 +/- 30)% of their respective values at 28.0 degrees C when warmed to 38.0 degrees C, in approximate agreement with earlier in vivo studies by others. During 30 min hypoxia NTP and PCr decreased to non-observable values, regardless of temperature. After reoxygenation, NTP and PCr recoveries as percentages of respective prehypoxia values were (63% +/- 16%; 70%) +/- 5%) for hypothermic slices (28.0 degrees C), and (46% +/- 13%; 41% +/- hypothermic neuroprotection during oxygen deprivation in this model, which appears suitable for use in further studies.

A simple method for multiday imaging of slice cultures.

PubMed

Seidl, Armin H; Rubel, Edwin W

2010-01-01

The organotypic slice culture (Stoppini et al. A simple method for organotypic cultures of nervous tissue. 1991;37:173-182) has become the method of choice to answer a variety of questions in neuroscience. For many experiments, however, it would be beneficial to image or manipulate a slice culture repeatedly, for example, over the course of many days. We prepared organotypic slice cultures of the auditory brainstem of P3 and P4 mice and kept them in vitro for up to 4 weeks. Single cells in the auditory brainstem were transfected with plasmids expressing fluorescent proteins by way of electroporation (Haas et al. Single-cell electroporation for gene transfer in vivo. 2001;29:583-591). The culture was then placed in a chamber perfused with oxygenated ACSF and the labeled cell imaged with an inverted wide-field microscope repeatedly for multiple days, recording several time-points per day, before returning the slice to the incubator. We describe a simple method to image a slice culture preparation during the course of multiple days and over many continuous hours, without noticeable damage to the tissue or photobleaching. Our method uses a simple, inexpensive custom-built insulator constructed around the microscope to maintain controlled temperature and uses a perfusion chamber as used for in vitro slice recordings. (c) 2009 Wiley-Liss, Inc.

Discovery of Hyperpolarized Molecular Imaging Biomarkers in a Novel Prostate Tissue Slice Culture Model

DTIC Science & Technology

2013-06-01

research is to optimize an MRS-compatible, 3D Tissue Culture Bioreactor for use with primary human prostate tissue cultures (TSCs) and use it to...Tissue Culture Bioreactor ” to be submitted to the Journal Magnetic Resonance in Medicine. CONCLUSIONS: We have engineered a robust MR compatible 3D ...loss of structure, function or metabolism within a NMR compatible 3-D tissue culture bioreactor , and that magnetic resonance spectroscopy studies of

Chest Fat Quantification via CT Based on Standardized Anatomy Space in Adult Lung Transplant Candidates

PubMed Central

Tong, Yubing; Udupa, Jayaram K.; Torigian, Drew A.; Odhner, Dewey; Wu, Caiyun; Pednekar, Gargi; Palmer, Scott; Rozenshtein, Anna; Shirk, Melissa A.; Newell, John D.; Porteous, Mary; Diamond, Joshua M.

2017-01-01

Purpose Overweight and underweight conditions are considered relative contraindications to lung transplantation due to their association with excess mortality. Yet, recent work suggests that body mass index (BMI) does not accurately reflect adipose tissue mass in adults with advanced lung diseases. Alternative and more accurate measures of adiposity are needed. Chest fat estimation by routine computed tomography (CT) imaging may therefore be important for identifying high-risk lung transplant candidates. In this paper, an approach to chest fat quantification and quality assessment based on a recently formulated concept of standardized anatomic space (SAS) is presented. The goal of the paper is to seek answers to several key questions related to chest fat quantity and quality assessment based on a single slice CT (whether in the chest, abdomen, or thigh) versus a volumetric CT, which have not been addressed in the literature. Methods Unenhanced chest CT image data sets from 40 adult lung transplant candidates (age 58 ± 12 yrs and BMI 26.4 ± 4.3 kg/m2), 16 with chronic obstructive pulmonary disease (COPD), 16 with idiopathic pulmonary fibrosis (IPF), and the remainder with other conditions were analyzed together with a single slice acquired for each patient at the L5 vertebral level and mid-thigh level. The thoracic body region and the interface between subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in the chest were consistently defined in all patients and delineated using Live Wire tools. The SAT and VAT components of chest were then segmented guided by this interface. The SAS approach was used to identify the corresponding anatomic slices in each chest CT study, and SAT and VAT areas in each slice as well as their whole volumes were quantified. Similarly, the SAT and VAT components were segmented in the abdomen and thigh slices. Key parameters of the attenuation (Hounsfield unit (HU) distributions) were determined from each chest slice and from the whole chest volume separately for SAT and VAT components. The same parameters were also computed from the single abdominal and thigh slices. The ability of the slice at each anatomic location in the chest (and abdomen and thigh) to act as a marker of the measures derived from the whole chest volume was assessed via Pearson correlation coefficient (PCC) analysis. Results The SAS approach correctly identified slice locations in different subjects in terms of vertebral levels. PCC between chest fat volume and chest slice fat area was maximal at the T8 level for SAT (0.97) and at the T7 level for VAT (0.86), and was modest between chest fat volume and abdominal slice fat area for SAT and VAT (0.73 and 0.75, respectively). However, correlation was weak for chest fat volume and thigh slice fat area for SAT and VAT (0.52 and 0.37, respectively), and for chest fat volume for SAT and VAT and BMI (0.65 and 0.28, respectively). These same single slice locations with maximal PCC were found for SAT and VAT within both COPD and IPF groups. Most of the attenuation properties derived from the whole chest volume and single best chest slice for VAT (but not for SAT) were significantly different between COPD and IPF groups. Conclusions This study demonstrates a new way of optimally selecting slices whose measurements may be used as markers of similar measurements made on the whole chest volume. The results suggest that one or two slices imaged at T7 and T8 vertebral levels may be enough to estimate reliably the total SAT and VAT components of chest fat and the quality of chest fat as determined by attenuation distributions in the entire chest volume. PMID:28046024

Chest Fat Quantification via CT Based on Standardized Anatomy Space in Adult Lung Transplant Candidates.

PubMed

Tong, Yubing; Udupa, Jayaram K; Torigian, Drew A; Odhner, Dewey; Wu, Caiyun; Pednekar, Gargi; Palmer, Scott; Rozenshtein, Anna; Shirk, Melissa A; Newell, John D; Porteous, Mary; Diamond, Joshua M; Christie, Jason D; Lederer, David J

2017-01-01

Overweight and underweight conditions are considered relative contraindications to lung transplantation due to their association with excess mortality. Yet, recent work suggests that body mass index (BMI) does not accurately reflect adipose tissue mass in adults with advanced lung diseases. Alternative and more accurate measures of adiposity are needed. Chest fat estimation by routine computed tomography (CT) imaging may therefore be important for identifying high-risk lung transplant candidates. In this paper, an approach to chest fat quantification and quality assessment based on a recently formulated concept of standardized anatomic space (SAS) is presented. The goal of the paper is to seek answers to several key questions related to chest fat quantity and quality assessment based on a single slice CT (whether in the chest, abdomen, or thigh) versus a volumetric CT, which have not been addressed in the literature. Unenhanced chest CT image data sets from 40 adult lung transplant candidates (age 58 ± 12 yrs and BMI 26.4 ± 4.3 kg/m2), 16 with chronic obstructive pulmonary disease (COPD), 16 with idiopathic pulmonary fibrosis (IPF), and the remainder with other conditions were analyzed together with a single slice acquired for each patient at the L5 vertebral level and mid-thigh level. The thoracic body region and the interface between subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in the chest were consistently defined in all patients and delineated using Live Wire tools. The SAT and VAT components of chest were then segmented guided by this interface. The SAS approach was used to identify the corresponding anatomic slices in each chest CT study, and SAT and VAT areas in each slice as well as their whole volumes were quantified. Similarly, the SAT and VAT components were segmented in the abdomen and thigh slices. Key parameters of the attenuation (Hounsfield unit (HU) distributions) were determined from each chest slice and from the whole chest volume separately for SAT and VAT components. The same parameters were also computed from the single abdominal and thigh slices. The ability of the slice at each anatomic location in the chest (and abdomen and thigh) to act as a marker of the measures derived from the whole chest volume was assessed via Pearson correlation coefficient (PCC) analysis. The SAS approach correctly identified slice locations in different subjects in terms of vertebral levels. PCC between chest fat volume and chest slice fat area was maximal at the T8 level for SAT (0.97) and at the T7 level for VAT (0.86), and was modest between chest fat volume and abdominal slice fat area for SAT and VAT (0.73 and 0.75, respectively). However, correlation was weak for chest fat volume and thigh slice fat area for SAT and VAT (0.52 and 0.37, respectively), and for chest fat volume for SAT and VAT and BMI (0.65 and 0.28, respectively). These same single slice locations with maximal PCC were found for SAT and VAT within both COPD and IPF groups. Most of the attenuation properties derived from the whole chest volume and single best chest slice for VAT (but not for SAT) were significantly different between COPD and IPF groups. This study demonstrates a new way of optimally selecting slices whose measurements may be used as markers of similar measurements made on the whole chest volume. The results suggest that one or two slices imaged at T7 and T8 vertebral levels may be enough to estimate reliably the total SAT and VAT components of chest fat and the quality of chest fat as determined by attenuation distributions in the entire chest volume.

Attenuation of Lipopolysaccharide-Induced Lung Vascular Stiffening by Lipoxin Reduces Lung Inflammation

PubMed Central

Meng, Fanyong; Mambetsariev, Isa; Tian, Yufeng; Beckham, Yvonne; Meliton, Angelo; Leff, Alan; Gardel, Margaret L.; Allen, Michael J.; Birukov, Konstantin G.

2015-01-01

Reversible changes in lung microstructure accompany lung inflammation, although alterations in tissue micromechanics and their impact on inflammation remain unknown. This study investigated changes in extracellular matrix (ECM) remodeling and tissue stiffness in a model of LPS-induced inflammation and examined the role of lipoxin analog 15-epi-lipoxin A4 (eLXA4) in the reduction of stiffness-dependent exacerbation of the inflammatory process. Atomic force microscopy measurements of live lung slices were used to directly measure local tissue stiffness changes induced by intratracheal injection of LPS. Effects of LPS on ECM properties and inflammatory response were evaluated in an animal model of LPS-induced lung injury, live lung tissue slices, and pulmonary endothelial cell (EC) culture. In vivo, LPS increased perivascular stiffness in lung slices monitored by atomic force microscopy and stimulated expression of ECM proteins fibronectin, collagen I, and ECM crosslinker enzyme, lysyl oxidase. Increased stiffness and ECM remodeling escalated LPS-induced VCAM1 and ICAM1 expression and IL-8 production by lung ECs. Stiffness-dependent exacerbation of inflammatory signaling was confirmed in pulmonary ECs grown on substrates with high and low stiffness. eLXA4 inhibited LPS-increased stiffness in lung cross sections, attenuated stiffness-dependent enhancement of EC inflammatory activation, and restored lung compliance in vivo. This study shows that increased local vascular stiffness exacerbates lung inflammation. Attenuation of local stiffening of lung vasculature represents a novel mechanism of lipoxin antiinflammatory action. PMID:24992633

Brain tissue stiffness is a sensitive marker for acidosis.

PubMed

Holtzmann, Kathrin; Gautier, Hélène O B; Christ, Andreas F; Guck, Jochen; Káradóttir, Ragnhildur Thóra; Franze, Kristian

2016-09-15

Carbon dioxide overdose is frequently used to cull rodents for tissue harvesting. However, this treatment may lead to respiratory acidosis, which potentially could change the properties of the investigated tissue. Mechanical tissue properties often change in pathological conditions and may thus offer a sensitive generic readout for changes in biological tissues with clinical relevance. In this study, we performed force-indentation measurements with an atomic force microscope on acute cerebellar slices from adult rats to test if brain tissue undergoes changes following overexposure to CO2 compared to other methods of euthanasia. The pH significantly decreased in brain tissue of animals exposed to CO2. Concomitant with the drop in pH, cerebellar grey matter significantly stiffened. Tissue stiffening was reproduced by incubation of acute cerebellar slices in acidic medium. Tissue stiffness provides an early, generic indicator for pathophysiological changes in the CNS. Atomic force microscopy offers unprecedented high spatial resolution to detect such changes. Our results indicate that the stiffness particularly of grey matter strongly correlates with changes of the pH in the cerebellum. Furthermore, the method of tissue harvesting and preparation may not only change tissue stiffness but very likely also other physiologically relevant parameters, highlighting the importance of appropriate sample preparation. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Geometry Processing of Conventionally Produced Mouse Brain Slice Images.

PubMed

Agarwal, Nitin; Xu, Xiangmin; Gopi, M

2018-04-21

Brain mapping research in most neuroanatomical laboratories relies on conventional processing techniques, which often introduce histological artifacts such as tissue tears and tissue loss. In this paper we present techniques and algorithms for automatic registration and 3D reconstruction of conventionally produced mouse brain slices in a standardized atlas space. This is achieved first by constructing a virtual 3D mouse brain model from annotated slices of Allen Reference Atlas (ARA). Virtual re-slicing of the reconstructed model generates ARA-based slice images corresponding to the microscopic images of histological brain sections. These image pairs are aligned using a geometric approach through contour images. Histological artifacts in the microscopic images are detected and removed using Constrained Delaunay Triangulation before performing global alignment. Finally, non-linear registration is performed by solving Laplace's equation with Dirichlet boundary conditions. Our methods provide significant improvements over previously reported registration techniques for the tested slices in 3D space, especially on slices with significant histological artifacts. Further, as one of the application we count the number of neurons in various anatomical regions using a dataset of 51 microscopic slices from a single mouse brain. To the best of our knowledge the presented work is the first that automatically registers both clean as well as highly damaged high-resolutions histological slices of mouse brain to a 3D annotated reference atlas space. This work represents a significant contribution to this subfield of neuroscience as it provides tools to neuroanatomist for analyzing and processing histological data. Copyright © 2018 Elsevier B.V. All rights reserved.

Urea Biosynthesis Using Liver Slices

ERIC Educational Resources Information Center

Teal, A. R.

1976-01-01

Presented is a practical scheme to enable introductory biology students to investigate the mechanism by which urea is synthesized in the liver. The tissue-slice technique is discussed, and methods for the quantitative analysis of metabolites are presented. (Author/SL)

Comparison of sliced lungs with whole lung sets for a torso phantom measured with Ge detectors using Monte Carlo simulations (MCNP).

PubMed

Kramer, Gary H; Guerriere, Steven

2003-02-01

Lung counters are generally used to measure low energy photons (<100 keV). They are usually calibrated with lung sets that are manufactured from a lung tissue substitute material that contains homogeneously distributed activity; however, it is difficult to verify either the activity in the phantom or the homogeneity of the activity distribution without destructive testing. Lung sets can have activities that are as much as 25% different from the expected value. An alternative method to using whole lungs to calibrate a lung counter is to use a sliced lung with planar inserts. Experimental work has already indicated that this alternative method of calibration can be a satisfactory substitute. This work has extended the experimental study by the use of Monte Carlo simulation to validate that sliced and whole lungs are equivalent. It also has determined the optimum slice thicknesses that separate the planar sources in the sliced lung. Slice thicknesses have been investigated in the range of 0.5 cm to 9.0 cm and at photon energies from 17 keV to 1,000 keV. Results have shown that there is little difference between sliced and whole lungs at low energies providing that the slice thickness is 2.0 cm or less. As the photon energy rises the slice thickness can increase substantially with no degradation on equivalence.

Imaging of cochlear tissue with a grating interferometer and hard X-rays

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

Richter, Claus-Peter; Shintani-Smith, Stephanie; Fishman, Andrew

This article addresses an important current development in medical and biological imaging: the possibility of imaging soft tissue at resolutions in the micron range using hard X-rays. Challenging environments, including the cochlea, require the imaging of soft tissue structure surrounded by bone. We demonstrate that cochlear soft tissue structures can be imaged with hard X-ray phase contrast. Furthermore, we show that only a thin slice of the tissue is required to introduce a large phase shift. It is likely that the phase contrast image of the soft tissue structures is sufficient to image the structures even if surrounded by bone.more » For the present set of experiments, structures with low-absorption contrast have been visualized using in-line phase contrast imaging and a grating interferometer. The experiments have been performed at the Advanced Photon Source at Argonne National Laboratories, a third generation source of synchrotron radiation. The source provides highly coherent X-ray radiation with high-photon flux (>10{sup 12} photons/s) at high-photon energies (5-70 keV). Radiographic and light microscopy images of the gerbil cochlear slice samples were compared. It has been determined that a 20-{micro}m thick tissue slice induces a phase shift between 1/3{pi} and 2/3{pi}.« less

Some Uses of Tissue Explants in the Teaching of Protein Synthesis

ERIC Educational Resources Information Center

King, B.

1977-01-01

Experiments are described in which inhibitors are used to investigate the timing of transcription and translation of the messenger RNA for the enzyme invertase. It is suggested that plant tissue slices provide adaptable material with which to study enzyme induction, protein synthesis, and cell differentiation at sixth-form level. (Author/MA)

Discovery of Hyperpolarized Molecular Imaging Biomarkers in a Novel Prostate Tissue Slice Culture Model

DTIC Science & Technology

2011-06-01

we tested was the addition ofN- acetylcysteine (NAC) to the medium. NAC protects cells from oxidative damage, and it is possible that our inability...of tissue procurement and spectral studies • Obtained preliminary data that an anti-oxidant, N- acetylcysteine , might extend longevity of TSCs

White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

NASA Astrophysics Data System (ADS)

Lefebvre, Joël.; Castonguay, Alexandre; Lesage, Frédéric

2017-02-01

A whole rodent brain was imaged using an automated massive histology setup and an Optical Coherence Tomography (OCT) microscope. Thousands of OCT volumetric tiles were acquired, each covering a size of about 2.5x2.5x0.8 mm3 with a sampling resolution of 4.9x4.9x6.5 microns. This paper shows the techniques for reconstruction, attenuation compensation and segmentation of the sliced brains. The tile positions within the mosaic were evaluated using a displacement model of the motorized stage and pairwise coregistration. Volume blending was then performed by solving the 3D Laplace equation, and consecutive slices were assembled using the cross-correlation of their 2D image gradient. This reconstruction algorithm resulted in a 3D map of optical reflectivity for the whole brain at micrometric resolution. OCT tissue slices were then used to estimate the local attenuation coefficient based on a single scattering photon model. The attenuation map obtained exhibits a high contrast for all white matter fibres, regardless of their orientation. The tissue optical attenuation from the intrinsic OCT reflectivity contributes to better white matter tissue segmentation. The combined 3D maps of reflectivity and attenuation is a step toward the study of white matter at a microscopic scale for the whole brain in small animals.

Impairment and restoration of response to TSH in dog thyroid slices after treatment with phospholipase A and lubrol PX.

PubMed

Yamashita, K; Oka, H; Kaneko, T; Ogata, E

1976-01-01

Incubation of dog thyroid slices with phospholipase A (10-40 U/Ml) or Lubrol PX (0.08-0.4%) caused a diminution in the subsequent TSH effect on the tissue cyclic AMP level and glucose oxidation. The same treatment had no effect on the basal level of these parameters. When the phospholipase A or Lubrol PX-treated slices were rinsed intensively with a Krebs-Ringer bicarbonate buffer and then incubated at 37degreesC in the same buffer for a further 1 to 3 hours, responsiveness to TSH recovered progressively reaching almost completely that of the control slices. Again, these procedures were without any significant effect on the responsiveness of the control slices. The above results together with those reported previously suggest strongly that phospholipids are an essential component of the plasma membrane system by which TSH stimulates adenylate cyclase activity. In addition, these essential lipids in the membrane appear to be renewed rather efficiently in this tissue, thus securing the functional integrity of the thyroid in the face of various deleterious situations.

Long-Term Tissue Culture of Adult Brain and Spleen Slices on Nanostructured Scaffolds.

PubMed

Kallendrusch, Sonja; Merz, Felicitas; Bechmann, Ingo; Mayr, Stefan G; Zink, Mareike

2017-05-01

Long-term tissue culture of adult mammalian organs is a highly promising approach to bridge the gap between single cell cultures and animal experiments, and bears the potential to reduce in vivo studies. Novel biomimetic materials open up new possibilities to maintain the complex tissue structure in vitro; however, survival times of adult tissues ex vivo are still limited to a few days with established state-of-the-art techniques. Here, it is demonstrated that TiO 2 nanotube scaffolds with specific tissue-tailored characteristics can serve as superior substrates for long-term adult brain and spleen tissue culture. High viability of the explants for at least two weeks is achieved and compared to tissues cultured on standard polytetrafluoroethylene (PTFE) membranes. Histological and immunohistochemical staining and live imaging are used to investigate tissue condition after 5 and 14 d in vitro, while environmental scanning electron microscopy qualifies the interaction with the underlying scaffold. In contrast to tissues cultured on PTFE membranes, enhanced tissue morphology is detected in spleen slices, as well as minor cell death in neuronal tissue, both cultured on nanotube scaffolds. This novel biomimetic tissue model will prove to be useful to address fundamental biological and medical questions from tissue regeneration up to tumor progression and therapeutic approaches. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Senescense

PubMed Central

De Leo, Pietro; Sacher, Joseph A.

1970-01-01

During ripening of banana (Musa sapientum L., var. Gros Michel or Valery) acid phosphatase activity increases 13-to 26-fold in the precipitate and 2- to 4-fold in the supernatant fraction of tissue homogenates. These increases are closely correlated with the onset and peak of the climacteric. The precipitate enzyme may be extracted with Triton X-100, CaCl2 or NaCl; about 80% of it is in a 500g precipitate. Studies on effect of tonicity of the grinding medium indicate that the precipitate enzyme is desorbed from membrane or cell wall surfaces, and is not released as a result of lysis of membranes. The development of acid phosphatase during aging of tissue slices is the same as in intact fruit. Short term studies of tissue slices with cycloheximide and actinomycin D indicate that the increase in activity is owed to new enzyme synthesis, which is dependent upon synthesis of RNA. The possible effects of the increase in acid phosphatase on ripening are discussed. PMID:16657436

Focal macromolecule delivery in neuronal tissue using simultaneous pressure ejection and local electroporation

PubMed Central

Barker, Matthew; Billups, Brian; Hamann, Martine

2009-01-01

Electroporation creates transient pores in the plasma membrane to introduce macromolecules within a cell or cell population. Generally, electrical pulses are delivered between two electrodes separated from each other, making electroporation less likely to be localised. We have developed a new device combining local pressure ejection with local electroporation through a double-barrelled glass micropipette to transfer impermeable macromolecules in brain slices or in cultured HEK293 cells. The design achieves better targeting of the site of pressure ejection with that of electroporation. With this technique, we have been able to limit the delivery of propidium iodide or dextran amine within areas of 100–200 μm diameter. We confirm that local electroporation is transient and show that when combined with pressure ejection, it allows local transfection of EGFP plasmids within HEK293 cells or within cerebellar and hippocampal slice cultures. We further show that local electroporation is less damaging when compared to global electroporation using two separate electrodes. Focal delivery of dextran amine dyes within trapezoid body fibres allowed tracing axonal tracts within brainstem slices, enabling the study of identified calyx of Held presynaptic terminals in living brain tissue. This labelling method can be used to target small nuclei in neuronal tissue and is generally applicable to the study of functional synaptic connectivity, or live axonal tracing in a variety of brain areas. PMID:19014970

A Novel Application for the Cavalieri Principle: A Stereological and Methodological Study

PubMed Central

Altunkaynak, Berrin Zuhal; Altunkaynak, Eyup; Unal, Deniz; Unal, Bunyamin

2009-01-01

Objective The Cavalieri principle was applied to consecutive pathology sections that were photographed at the same magnification and used to estimate tissue volumes via superimposing a point counting grid on these images. The goal of this study was to perform the Cavalieri method quickly and practically. Materials and Methods In this study, 10 adult female Sprague Dawley rats were used. Brain tissue was removed and sampled both systematically and randomly. Brain volumes were estimated using two different methods. First, all brain slices were scanned with an HP ScanJet 3400C scanner, and their images were shown on a PC monitor. Brain volume was then calculated based on these images. Second, all brain slices were photographed in 10× magnification with a microscope camera, and brain volumes were estimated based on these micrographs. Results There was no statistically significant difference between the volume measurements of the two techniques (P>0.05; Paired Samples t Test). Conclusion This study demonstrates that personal computer scanning of serial tissue sections allows for easy and reliable volume determination based on the Cavalieri method. PMID:25610077

A novel application for the cavalieri principle: a stereological and methodological study.

PubMed

Altunkaynak, Berrin Zuhal; Altunkaynak, Eyup; Unal, Deniz; Unal, Bunyamin

2009-08-01

The Cavalieri principle was applied to consecutive pathology sections that were photographed at the same magnification and used to estimate tissue volumes via superimposing a point counting grid on these images. The goal of this study was to perform the Cavalieri method quickly and practically. In this study, 10 adult female Sprague Dawley rats were used. Brain tissue was removed and sampled both systematically and randomly. Brain volumes were estimated using two different methods. First, all brain slices were scanned with an HP ScanJet 3400C scanner, and their images were shown on a PC monitor. Brain volume was then calculated based on these images. Second, all brain slices were photographed in 10× magnification with a microscope camera, and brain volumes were estimated based on these micrographs. There was no statistically significant difference between the volume measurements of the two techniques (P>0.05; Paired Samples t Test). This study demonstrates that personal computer scanning of serial tissue sections allows for easy and reliable volume determination based on the Cavalieri method.

A study of cryogenic tissue-engineered liver slices in calcium alginate gel for drug testing.

PubMed

Chen, Ruomeng; Wang, Bo; Liu, Yaxiong; Lin, Rong; He, Jiankang; Li, Dichen

2018-06-01

To address issues such as transportation and the time-consuming nature of tissue-engineered liver for use as an effective drug metabolism and toxicity testing model, "ready-to-use" cryogenic tissue-engineered liver needs to be studied. The research developed a cryogenic tissue-engineered liver slice (TELS), which comprised of HepG2 cells and calcium alginate gel. Cell viability and liver-specific functions were examined after different cryopreservation and recovery culture times. Then, cryogenic TELSs were used as a drug-testing model and treated with Gefitinib. Cryogenic TELSs were stored at -80 °C to ensure high cell viability. During recovery in culture, the cells in the cryogenic TELS were evenly distributed, massively proliferated, and then formed spheroid-like aggregates from day 1 to day 13. The liver-specific functions in the cryogenic TELS were closely related to cryopreservation time and cell proliferation. As a reproducible drug-testing model, the cryogenic TELS showed an obvious drug reaction after treatment with the Gefitinib. The present study shows that the cryopreservation techniques can be used in drug-testing models. Copyright © 2018 Elsevier Inc. All rights reserved.

Modeling tuberculosis pathogenesis through ex vivo lung tissue infection.

PubMed

Carranza-Rosales, Pilar; Carranza-Torres, Irma Edith; Guzmán-Delgado, Nancy Elena; Lozano-Garza, Gerardo; Villarreal-Treviño, Licet; Molina-Torres, Carmen; Villarreal, Javier Vargas; Vera-Cabrera, Lucio; Castro-Garza, Jorge

2017-12-01

Tuberculosis (TB) is one of the top 10 causes of death worldwide. Several in vitro and in vivo experimental models have been used to study TB pathogenesis and induction of immune response during Mycobacterium tuberculosis infection. Precision cut lung tissue slices (PCLTS) is an experimental model, in which all the usual cell types of the organ are found, the tissue architecture and the interactions amongst the different cells are maintained. PCLTS in good physiological conditions, monitored by MTT assay and histology, were infected with either virulent Mycobacterium tuberculosis strain H37Rv or the TB vaccine strain Mycobacterium bovis BCG. Histological analysis showed that bacilli infecting lung tissue slices were observed in the alveolar septa, alveolar light spaces, near to type II pneumocytes, and inside macrophages. Mycobacterial infection of PCLTS induced TNF-α production, which is consistent with previous M. tuberculosis in vitro and in vivo studies. This is the first report of using PCLTS as a system to study M. tuberculosis infection. The PCLTS model provides a useful tool to evaluate the innate immune responses and other aspects during the early stages of mycobacterial infection. Copyright © 2017. Published by Elsevier Ltd.

Pyruvate incubation enhances glycogen stores and sustains neuronal function during subsequent glucose deprivation.

PubMed

Shetty, Pavan K; Sadgrove, Matthew P; Galeffi, Francesca; Turner, Dennis A

2012-01-01

The use of energy substrates, such as lactate and pyruvate, has been shown to improve synaptic function when administered during glucose deprivation. In the present study, we investigated whether prolonged incubation with monocarboxylate (pyruvate or lactate) prior rather than during glucose deprivation can also sustain synaptic and metabolic function. Pyruvate pre-incubation(3-4h) significantly prolonged (>25 min) the tolerance of rat hippocampal slices to delayed glucose deprivation compared to control and lactate pre-incubated slices, as revealed by field excitatory post synaptic potentials (fEPSPs); pre-incubation with pyruvate also reduced the marked decrease in NAD(P)H fluorescence resulting from glucose deprivation. Moreover, pyruvate exposure led to the enhancement of glycogen stores with time, compared to glucose alone (12 μmol/g tissue at 4h vs. 3.5 μmol/g tissue). Prolonged resistance to glucose deprivation following exogenous pyruvate incubation was prevented by glycogenolysis inhibitors, suggesting that enhanced glycogen mediates the delay in synaptic activity failure. The application of an adenosine A1 receptor antagonist enhanced glycogen utilization and prolonged the time to synaptic failure, further confirming this hypothesis of the importance of glycogen. Moreover, tissue levels of ATP were also significantly maintained during glucose deprivation in pyruvate pretreated slices compared to control and lactate. In summary, these experiments indicate that pyruvate exposure prior to glucose deprivation significantly increased the energy buffering capacity of hippocampal slices, particularly by enhancing internal glycogen stores, delaying synaptic failure during glucose deprivation by maintaining ATP levels, and minimizing the decrease in the levels of NAD(P)H. Copyright © 2011 Elsevier Inc. All rights reserved.

Analysis of acute brain slices by electron microscopy: a correlative light-electron microscopy workflow based on Tokuyasu cryo-sectioning.

PubMed

Loussert Fonta, Celine; Leis, Andrew; Mathisen, Cliff; Bouvier, David S; Blanchard, Willy; Volterra, Andrea; Lich, Ben; Humbel, Bruno M

2015-01-01

Acute brain slices are slices of brain tissue that are kept vital in vitro for further recordings and analyses. This tool is of major importance in neurobiology and allows the study of brain cells such as microglia, astrocytes, neurons and their inter/intracellular communications via ion channels or transporters. In combination with light/fluorescence microscopies, acute brain slices enable the ex vivo analysis of specific cells or groups of cells inside the slice, e.g. astrocytes. To bridge ex vivo knowledge of a cell with its ultrastructure, we developed a correlative microscopy approach for acute brain slices. The workflow begins with sampling of the tissue and precise trimming of a region of interest, which contains GFP-tagged astrocytes that can be visualised by fluorescence microscopy of ultrathin sections. The astrocytes and their surroundings are then analysed by high resolution scanning transmission electron microscopy (STEM). An important aspect of this workflow is the modification of a commercial cryo-ultramicrotome to observe the fluorescent GFP signal during the trimming process. It ensured that sections contained at least one GFP astrocyte. After cryo-sectioning, a map of the GFP-expressing astrocytes is established and transferred to correlation software installed on a focused ion beam scanning electron microscope equipped with a STEM detector. Next, the areas displaying fluorescence are selected for high resolution STEM imaging. An overview area (e.g. a whole mesh of the grid) is imaged with an automated tiling and stitching process. In the final stitched image, the local organisation of the brain tissue can be surveyed or areas of interest can be magnified to observe fine details, e.g. vesicles or gold labels on specific proteins. The robustness of this workflow is contingent on the quality of sample preparation, based on Tokuyasu's protocol. This method results in a reasonable compromise between preservation of morphology and maintenance of antigenicity. Finally, an important feature of this approach is that the fluorescence of the GFP signal is preserved throughout the entire preparation process until the last step before electron microscopy. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Calcium Imaging of AM Dyes Following Prolonged Incubation in Acute Neuronal Tissue

PubMed Central

Morley, John W.; Tapson, Jonathan; Breen, Paul P.; van Schaik, André

2016-01-01

Calcium-imaging is a sensitive method for monitoring calcium dynamics during neuronal activity. As intracellular calcium concentration is correlated to physiological and pathophysiological activity of neurons, calcium imaging with fluorescent indicators is one of the most commonly used techniques in neuroscience today. Current methodologies for loading calcium dyes into the tissue require prolonged incubation time (45–150 min), in addition to dissection and recovery time after the slicing procedure. This prolonged incubation curtails experimental time, as tissue is typically maintained for 6–8 hours after slicing. Using a recently introduced recovery chamber that extends the viability of acute brain slices to more than 24 hours, we tested the effectiveness of calcium AM staining following long incubation periods post cell loading and its impact on the functional properties of calcium signals in acute brain slices and wholemount retinae. We show that calcium dyes remain within cells and are fully functional >24 hours after loading. Moreover, the calcium dynamics recorded >24 hrs were similar to the calcium signals recorded in fresh tissue that was incubated for <4 hrs. These results indicate that long exposure of calcium AM dyes to the intracellular cytoplasm did not alter the intracellular calcium concentration, the functional range of the dye or viability of the neurons. This data extends our previous work showing that a custom recovery chamber can extend the viability of neuronal tissue, and reliable data for both electrophysiology and imaging can be obtained >24hrs after dissection. These methods will not only extend experimental time for those using acute neuronal tissue, but also may reduce the number of animals required to complete experimental goals. PMID:27183102

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method.

PubMed

Ting, Jonathan T; Lee, Brian R; Chong, Peter; Soler-Llavina, Gilberto; Cobbs, Charles; Koch, Christof; Zeng, Hongkui; Lein, Ed

2018-02-26

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method

PubMed Central

Chong, Peter; Soler-Llavina, Gilberto; Cobbs, Charles; Koch, Christof; Zeng, Hongkui; Lein, Ed

2018-01-01

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation. PMID:29553547

Controlled single bubble cavitation collapse results in jet-induced injury in brain tissue.

PubMed

Canchi, Saranya; Kelly, Karen; Hong, Yu; King, Michael A; Subhash, Ghatu; Sarntinoranont, Malisa

2017-10-01

Multiscale damage due to cavitation is considered as a potential mechanism of traumatic brain injury (TBI) associated with explosion. In this study, we employed a TBI relevant hippocampal ex vivo slice model to induce bubble cavitation. Placement of single reproducible seed bubbles allowed control of size, number, and tissue location to visualize and measure deformation parameters. Maximum strain value was measured at 45 µs after bubble collapse, presented with a distinct contour and coincided temporally and spatially with the liquid jet. Composite injury maps combined this maximum strain value with maximum measured bubble size and location along with histological injury patterns. This facilitated the correlation of bubble location and subsequent jet direction to the corresponding regions of high strain which overlapped with regions of observed injury. A dynamic threshold strain range for tearing of cerebral cortex was estimated to be between 0.5 and 0.6. For a seed bubble placed underneath the hippocampus, cavitation induced damage was observed in hippocampus (local), proximal cerebral cortex (marginal) and the midbrain/forebrain (remote) upon histological evaluation. Within this test model, zone of cavitation injury was greater than the maximum radius of the bubble. Separation of apposed structures, tissue tearing, and disruption of cellular layers defined early injury patterns that were not detected in the blast-exposed half of the brain slice. Ultrastructural pathology of the neurons exposed to cavitation was characterized by disintegration of plasma membrane along with loss of cellular content. The developed test system provided a controlled experimental platform to study cavitation induced high strain deformations on brain tissue slice. The goal of the future studies will be to lower underpressure magnitude and cavitation bubble size for more sensitive evaluation of injury. Copyright © 2017 Elsevier Ltd. All rights reserved.

3D prostate histology image reconstruction: Quantifying the impact of tissue deformation and histology section location

PubMed Central

Gibson, Eli; Gaed, Mena; Gómez, José A.; Moussa, Madeleine; Pautler, Stephen; Chin, Joseph L.; Crukley, Cathie; Bauman, Glenn S.; Fenster, Aaron; Ward, Aaron D.

2013-01-01

Background: Guidelines for localizing prostate cancer on imaging are ideally informed by registered post-prostatectomy histology. 3D histology reconstruction methods can support this by reintroducing 3D spatial information lost during histology processing. The need to register small, high-grade foci drives a need for high accuracy. Accurate 3D reconstruction method design is impacted by the answers to the following central questions of this work. (1) How does prostate tissue deform during histology processing? (2) What spatial misalignment of the tissue sections is induced by microtome cutting? (3) How does the choice of reconstruction model affect histology reconstruction accuracy? Materials and Methods: Histology, paraffin block face and magnetic resonance images were acquired for 18 whole mid-gland tissue slices from six prostates. 7-15 homologous landmarks were identified on each image. Tissue deformation due to histology processing was characterized using the target registration error (TRE) after landmark-based registration under four deformation models (rigid, similarity, affine and thin-plate-spline [TPS]). The misalignment of histology sections from the front faces of tissue slices was quantified using manually identified landmarks. The impact of reconstruction models on the TRE after landmark-based reconstruction was measured under eight reconstruction models comprising one of four deformation models with and without constraining histology images to the tissue slice front faces. Results: Isotropic scaling improved the mean TRE by 0.8-1.0 mm (all results reported as 95% confidence intervals), while skew or TPS deformation improved the mean TRE by <0.1 mm. The mean misalignment was 1.1-1.9° (angle) and 0.9-1.3 mm (depth). Using isotropic scaling, the front face constraint raised the mean TRE by 0.6-0.8 mm. Conclusions: For sub-millimeter accuracy, 3D reconstruction models should not constrain histology images to the tissue slice front faces and should be flexible enough to model isotropic scaling. PMID:24392245

Time efficient whole-brain coverage with MR Fingerprinting using slice-interleaved echo-planar-imaging.

PubMed

Rieger, Benedikt; Akçakaya, Mehmet; Pariente, José C; Llufriu, Sara; Martinez-Heras, Eloy; Weingärtner, Sebastian; Schad, Lothar R

2018-04-27

Magnetic resonance fingerprinting (MRF) is a promising method for fast simultaneous quantification of multiple tissue parameters. The objective of this study is to improve the coverage of MRF based on echo-planar imaging (MRF-EPI) by using a slice-interleaved acquisition scheme. For this, the MRF-EPI is modified to acquire several slices in a randomized interleaved manner, increasing the effective repetition time of the spoiled gradient echo readout acquisition in each slice. Per-slice matching of the signal-trace to a precomputed dictionary allows the generation of T 1 and T 2 * maps with integrated B 1 + correction. Subsequent compensation for the coil sensitivity profile and normalization to the cerebrospinal fluid additionally allows for quantitative proton density (PD) mapping. Numerical simulations are performed to optimize the number of interleaved slices. Quantification accuracy is validated in phantom scans and feasibility is demonstrated in-vivo. Numerical simulations suggest the acquisition of four slices as a trade-off between quantification precision and scan-time. Phantom results indicate good agreement with reference measurements (Difference T 1 : -2.4 ± 1.1%, T 2 *: -0.5 ± 2.5%, PD: -0.5 ± 7.2%). In-vivo whole-brain coverage of T 1 , T 2 * and PD with 32 slices was acquired within 3:36 minutes, resulting in parameter maps of high visual quality and comparable performance with single-slice MRF-EPI at 4-fold scan-time reduction.

Banking for the future: an Australian experience in brain banking.

PubMed

Sarris, M; Garrick, T M; Sheedy, D; Harper, C G

2002-06-01

The New South Wales (NSW) Tissue Resource Centre (TRC) has been set up to provide Australian and international researchers with fixed and frozen brain tissue from cases that are well characterised, both clinically and pathologically, for projects related to neuropsychiatric and alcohol-related disorders. A daily review of the Department of Forensic Medicine provides initial information regarding a potential collection. If the case adheres to the strict inclusion criteria, the pathologist performing the postmortem examination is approached regarding retention of the brain tissue. The next of kin of the deceased is then contacted requesting permission to retain the brain for medical research. Cases are also obtained through donor programmes, where donors are assessed and consent to donate their brain during life. Once the brain is removed at autopsy, the brain is photographed, weighed and the volume determined, the brainstem and cerebellum are removed. The two hemispheres are divided, one hemisphere is fresh frozen and one fixed (randomised). Prior to freezing, the hemisphere is sliced into 1-cm coronal slices and a set of critical area blocks is taken. All frozen tissues are kept bagged at -80 degrees C. The other hemisphere is fixed in 15% buffered formalin for 2 weeks, embedded in agar and sliced at 3-mm intervals in the coronal plane. Tissue blocks from these slices are used for neuropathological analysis to exclude any other pathology. The TRC currently has 230 cases of both fixed and frozen material that has proven useful in a range of techniques in many research projects. These techniques include quantitative analyses of brain regions using neuropathological, neurochemical, neuropharmacological and gene expression assays.

A rapid approach to high-resolution fluorescence imaging in semi-thick brain slices.

PubMed

Selever, Jennifer; Kong, Jian-Qiang; Arenkiel, Benjamin R

2011-07-26

A fundamental goal to both basic and clinical neuroscience is to better understand the identities, molecular makeup, and patterns of connectivity that are characteristic to neurons in both normal and diseased brain. Towards this, a great deal of effort has been placed on building high-resolution neuroanatomical maps(1-3). With the expansion of molecular genetics and advances in light microscopy has come the ability to query not only neuronal morphologies, but also the molecular and cellular makeup of individual neurons and their associated networks(4). Major advances in the ability to mark and manipulate neurons through transgenic and gene targeting technologies in the rodent now allow investigators to 'program' neuronal subsets at will(5-6). Arguably, one of the most influential contributions to contemporary neuroscience has been the discovery and cloning of genes encoding fluorescent proteins (FPs) in marine invertebrates(7-8), alongside their subsequent engineering to yield an ever-expanding toolbox of vital reporters(9). Exploiting cell type-specific promoter activity to drive targeted FP expression in discrete neuronal populations now affords neuroanatomical investigation with genetic precision. Engineering FP expression in neurons has vastly improved our understanding of brain structure and function. However, imaging individual neurons and their associated networks in deep brain tissues, or in three dimensions, has remained a challenge. Due to high lipid content, nervous tissue is rather opaque and exhibits auto fluorescence. These inherent biophysical properties make it difficult to visualize and image fluorescently labelled neurons at high resolution using standard epifluorescent or confocal microscopy beyond depths of tens of microns. To circumvent this challenge investigators often employ serial thin-section imaging and reconstruction methods(10), or 2-photon laser scanning microscopy(11). Current drawbacks to these approaches are the associated labor-intensive tissue preparation, or cost-prohibitive instrumentation respectively. Here, we present a relatively rapid and simple method to visualize fluorescently labelled cells in fixed semi-thick mouse brain slices by optical clearing and imaging. In the attached protocol we describe the methods of: 1) fixing brain tissue in situ via intracardial perfusion, 2) dissection and removal of whole brain, 3) stationary brain embedding in agarose, 4) precision semi-thick slice preparation using new vibratome instrumentation, 5) clearing brain tissue through a glycerol gradient, and 6) mounting on glass slides for light microscopy and z-stack reconstruction (Figure 1). For preparing brain slices we implemented a relatively new piece of instrumentation called the 'Compresstome' VF-200 (http://www.precisionary.com/products_vf200.html). This instrument is a semi-automated microtome equipped with a motorized advance and blade vibration system with features similar in function to other vibratomes. Unlike other vibratomes, the tissue to be sliced is mounted in an agarose plug within a stainless steel cylinder. The tissue is extruded at desired thicknesses from the cylinder, and cut by the forward advancing vibrating blade. The agarose plug/cylinder system allows for reproducible tissue mounting, alignment, and precision cutting. In our hands, the 'Compresstome' yields high quality tissue slices for electrophysiology, immunohistochemistry, and direct fixed-tissue mounting and imaging. Combined with optical clearing, here we demonstrate the preparation of semi-thick fixed brain slices for high-resolution fluorescent imaging.

Kidney segmentation in CT sequences using graph cuts based active contours model and contextual continuity.

PubMed

Zhang, Pin; Liang, Yanmei; Chang, Shengjiang; Fan, Hailun

2013-08-01

Accurate segmentation of renal tissues in abdominal computed tomography (CT) image sequences is an indispensable step for computer-aided diagnosis and pathology detection in clinical applications. In this study, the goal is to develop a radiology tool to extract renal tissues in CT sequences for the management of renal diagnosis and treatments. In this paper, the authors propose a new graph-cuts-based active contours model with an adaptive width of narrow band for kidney extraction in CT image sequences. Based on graph cuts and contextual continuity, the segmentation is carried out slice-by-slice. In the first stage, the middle two adjacent slices in a CT sequence are segmented interactively based on the graph cuts approach. Subsequently, the deformable contour evolves toward the renal boundaries by the proposed model for the kidney extraction of the remaining slices. In this model, the energy function combining boundary with regional information is optimized in the constructed graph and the adaptive search range is determined by contextual continuity and the object size. In addition, in order to reduce the complexity of the min-cut computation, the nodes in the graph only have n-links for fewer edges. The total 30 CT images sequences with normal and pathological renal tissues are used to evaluate the accuracy and effectiveness of our method. The experimental results reveal that the average dice similarity coefficient of these image sequences is from 92.37% to 95.71% and the corresponding standard deviation for each dataset is from 2.18% to 3.87%. In addition, the average automatic segmentation time for one kidney in each slice is about 0.36 s. Integrating the graph-cuts-based active contours model with contextual continuity, the algorithm takes advantages of energy minimization and the characteristics of image sequences. The proposed method achieves effective results for kidney segmentation in CT sequences.

The physiology of rodent beta-cells in pancreas slices.

PubMed

Rupnik, M

2009-01-01

Beta-cells in pancreatic islets form complex syncytia. Sufficient cell-to-cell electrical coupling seems to ensure coordinated depolarization pattern and insulin release that can be further modulated by rich innervation. The complex structure and coordinated action develop after birth during fast proliferation of the endocrine tissue. These emergent properties can be lost due to various reasons later in life and can lead to glucose intolerance and diabetes mellitus. Pancreas slice is a novel method of choice to study the physiology of beta-cells still embedded in their normal cellulo-social context. I present major advantages, list drawbacks and provide an overview on recent advances in our understanding of the physiology of beta-cells using the pancreas slice approach.

Monitoring the Secretory Behavior of the Rat Adrenal Medulla by High-Performance Liquid Chromatography-Based Catecholamine Assay from Slice Supernatants

PubMed Central

De Nardi, Frédéric; Lefort, Claudie; Bréard, Dimitri; Richomme, Pascal; Legros, Christian; Guérineau, Nathalie C.

2017-01-01

Catecholamine (CA) secretion from the adrenal medullary tissue is a key step of the adaptive response triggered by an organism to cope with stress. Whereas molecular and cellular secretory processes have been extensively studied at the single chromaffin cell level, data available for the whole gland level are much scarcer. We tackled this issue in rat by developing an easy to implement experimental strategy combining the adrenal acute slice supernatant collection with a high-performance liquid chromatography-based epinephrine and norepinephrine (NE) assay. This technique affords a convenient method for measuring basal and stimulated CA release from single acute slices, allowing thus to individually address the secretory function of the left and right glands. Our data point that the two glands are equally competent to secrete epinephrine and NE, exhibiting an equivalent epinephrine:NE ratio, both at rest and in response to a cholinergic stimulation. Nicotine is, however, more efficient than acetylcholine to evoke NE release. A pharmacological challenge with hexamethonium, an α3-containing nicotinic acetylcholine receptor antagonist, disclosed that epinephrine- and NE-secreting chromaffin cells distinctly expressed α3 nicotinic receptors, with a dominant contribution in NE cells. As such, beyond the novelty of CA assays from acute slice supernatants, our study contributes at refining the secretory behavior of the rat adrenal medullary tissue, and opens new perspectives for monitoring the release of other hormones and transmitters, especially those involved in the stress response. PMID:28993760

The reliability of a segmentation methodology for assessing intramuscular adipose tissue and other soft-tissue compartments of lower leg MRI images.

PubMed

Karampatos, Sarah; Papaioannou, Alexandra; Beattie, Karen A; Maly, Monica R; Chan, Adrian; Adachi, Jonathan D; Pritchard, Janet M

2016-04-01

Determine the reliability of a magnetic resonance (MR) image segmentation protocol for quantifying intramuscular adipose tissue (IntraMAT), subcutaneous adipose tissue, total muscle and intermuscular adipose tissue (InterMAT) of the lower leg. Ten axial lower leg MRI slices were obtained from 21 postmenopausal women using a 1 Tesla peripheral MRI system. Images were analyzed using sliceOmatic™ software. The average cross-sectional areas of the tissues were computed for the ten slices. Intra-rater and inter-rater reliability were determined and expressed as the standard error of measurement (SEM) (absolute reliability) and intraclass coefficient (ICC) (relative reliability). Intra-rater and inter-rater reliability for IntraMAT were 0.991 (95% confidence interval [CI] 0.978-0.996, p < 0.05) and 0.983 (95% CI 0.958-9.993, p < 0.05), respectively. For the other soft tissue compartments, the ICCs were all >0.90 (p < 0.05). The absolute intra-rater and inter-rater reliability (expressed as SEM) for segmenting IntraMAT were 22.19 mm(2) (95% CI 16.97-32.04) and 78.89 mm(2) (95% CI 60.36-113.92), respectively. This is a reliable segmentation protocol for quantifying IntraMAT and other soft-tissue compartments of the lower leg. A standard operating procedure manual is provided to assist users, and SEM values can be used to estimate sample size and determine confidence in repeated measurements in future research.

Phospholipid Synthesis in Aging Potato Tuber Tissue 1

PubMed Central

Tang, Wen-Jing; Castelfranco, Paul A.

1968-01-01

The effect of activation (“aging”) of potato tuber slices on their phospholipid metabolism was investigated. Aged slices were incubated with 14C labeled choline, ethanolamine, methionine, serine, and acetate. In all cases, the incorporation of radioactivity into the lipid fraction increased with the length of time the slices were aged. This incorporation was shown to be true synthesis and not exchange between precursors and existing phospholipids. The increased incorporation of labeled choline into lipids was mainly due to an increase in its uptake by the tissue, the presence of actidione during aging prevented this increased uptake. The increase in the incorporation of labeled acetate into lipids resulted from the development of a fatty acid synthetase during aging. In the case of ethanolamine, both its uptake into the tissue and its incorporation into the lipid fraction increased. The phospholipids formed from these precursors were identified by paper and thin-layer chromatography. The major compound formed from choline was lecithin, while phosphatidylethanolamine and a small amount of lecithin were formed from ethanolamine. Images PMID:16656906

Development of a high-throughput brain slice method for studying drug distribution in the central nervous system.

PubMed

Fridén, Markus; Ducrozet, Frederic; Middleton, Brian; Antonsson, Madeleine; Bredberg, Ulf; Hammarlund-Udenaes, Margareta

2009-06-01

New, more efficient methods of estimating unbound drug concentrations in the central nervous system (CNS) combine the amount of drug in whole brain tissue samples measured by conventional methods with in vitro estimates of the unbound brain volume of distribution (V(u,brain)). Although the brain slice method is the most reliable in vitro method for measuring V(u,brain), it has not previously been adapted for the needs of drug discovery research. The aim of this study was to increase the throughput and optimize the experimental conditions of this method. Equilibrium of drug between the buffer and the brain slice within the 4 to 5 h of incubation is a fundamental requirement. However, it is difficult to meet this requirement for many of the extensively binding, lipophilic compounds in drug discovery programs. In this study, the dimensions of the incubation vessel and mode of stirring influenced the equilibration time, as did the amount of brain tissue per unit of buffer volume. The use of cassette experiments for investigating V(u,brain) in a linear drug concentration range increased the throughput of the method. The V(u,brain) for the model compounds ranged from 4 to 3000 ml . g brain(-1), and the sources of variability are discussed. The optimized setup of the brain slice method allows precise, robust estimation of V(u,brain) for drugs with diverse properties, including highly lipophilic compounds. This is a critical step forward for the implementation of relevant measurements of CNS exposure in the drug discovery setting.

EFFECT OF ABDOMINAL SHIELDING ON THE METABOLISM OF HYDROCORTISONE BY LIVER TISSUE OF X-IRRADIATED RATS

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

Lott, J.R.

Liver slices removed from adult rats at various times following whole body x-irradiations of 850, 1500, and 2000 r were tested for their ability to metabolize hydrocortisone ( free alcohol). The animals were divided into a non- irradiated control group, an irradiated unshielded group, and an abdominal- shielded irradiated group. It was found that the irradiated unshielded liver slices metabo lized the hydrocortisone at a lower rate than control slices. Liver slices removed from animals whose abdominal regions were shielded during irradiation were found to metabolize hydrocortisone at a higher rate than control slices. The effects observed appeared to bemore » dependent on total dosage and time of removal of the liver post-irradiation. (auth)« less

Preclinical evaluation of transcriptional targeting strategies for carcinoma of the breast in a tissue slice model system

PubMed Central

Stoff-Khalili, Mariam A; Stoff, Alexander; Rivera, Angel A; Banerjee, Nilam S; Everts, Maaike; Young, Scott; Siegal, Gene P; Richter, Dirk F; Wang, Minghui; Dall, Peter; Mathis, J Michael; Zhu, Zeng B; Curiel, David T

2005-01-01

Introduction In view of the limited success of available treatment modalities for metastatic breast cancer, alternative and complementary strategies need to be developed. Adenoviral vector mediated strategies for breast cancer gene therapy and virotherapy are a promising novel therapeutic platform for the treatment of breast cancer. However, the promiscuous tropism of adenoviruses (Ads) is a major concern. Employing tissue specific promoters (TSPs) to restrict transgene expression or viral replication is an effective way to increase specificity towards tumor tissues and to reduce adverse effects in non-target tissues such as the liver. In this regard, candidate breast cancer TSPs include promoters of the genes for the epithelial glycoprotein 2 (EGP-2), cyclooxygenase-2 (Cox-2), α-chemokine SDF-1 receptor (stromal-cell-derived factor, CXCR4), secretory leukoprotease inhibitor (SLPI) and survivin. Methods We employed E1-deleted Ads that express the reporter gene luciferase under the control of the promoters of interest. We evaluated this class of vectors in various established breast cancer cell lines, primary breast cancer cells and finally in the most stringent preclinical available substrate system, constituted by precision cut tissue slices of human breast cancer and liver. Results Overall, the CXCR4 promoter exhibited the highest luciferase activity in breast cancer cell lines, primary breast cancer cells and breast cancer tissue slices. Importantly, the CXCR4 promoter displayed a very low activity in human primary fibroblasts and human liver tissue slices. Interestingly, gene expression profiles correlated with the promoter activities both in breast cancer cell lines and primary breast cancer cells. Conclusion These data suggest that the CXCR4 promoter has an ideal 'breast cancer-on/liver-off' profile, and could, therefore, be a powerful tool in Ad vector based gene therapy or virotherapy of the carcinoma of the breast. PMID:16457694

The significance of folic acid, tissue iron stores, and tissue viability in determining iron uptake from serum by thyroid tissue slices

PubMed Central

Buchanan, W. M.

1971-01-01

This paper describes an attempt to measure in vitro iron uptake from serum by human thyroid slices and to relate the uptake to tissue iron stores, folic acid status, and tissue viability. It is an extension of work previously reported (Buchanan, 1969). Thyroids were obtained from patients undergoing partial thyroidectomy for colloid goitre and serum from clinically normal healthy adults. The haemoglobin, serum iron, and folic acid levels of both thyroid and serum donors were measured and thyroids examined histologically for the presence of stainable iron. Viable and non-viable tissue slices were incubated in sera treated with radioactive iron so as to produce high and normal levels of transferrin saturation. Iron was taken up both from sera with normal and high transferrin saturation but the amount was, in almost all cases, greater from the more highly saturated. The uptake by non-viable tissue was appreciable but did not vary to any great extent from one serum to the next, and was attributed to simple diffusion of ionic iron into the tissue. There was, however, marked variation in uptake from different sera by viable tissue. It was concluded therefore that viability is a factor affecting the uptake. As the variation in uptake by viable tissue incubated in a single serum was significantly less than tissue incubated in a number of different sera it was further concluded that there was also a factor in the serum itself affecting iron uptake. The nature of the factor was not elucidated but neither folic acid nor levels of iron stores appeared to influence uptake because no correlation was found between iron uptake and iron stores or folic acid. Images PMID:5556118

Enhanced synthesis and release of dopamine in transgenic mice with gain-of-function α6* nAChRs.

PubMed

Wang, Yuexiang; Lee, Jang-Won; Oh, Gyeon; Grady, Sharon R; McIntosh, J Michael; Brunzell, Darlene H; Cannon, Jason R; Drenan, Ryan M

2014-04-01

α6β2* nicotinic acetylcholine receptors (nAChRs)s in the ventral tegmental area to nucleus accumbens (NAc) pathway are implicated in the response to nicotine, and recent work suggests these receptors play a role in the rewarding action of ethanol. Here, we studied mice expressing gain-of-function α6β2* nAChRs (α6L9'S mice) that are hypersensitive to nicotine and endogenous acetylcholine. Evoked extracellular dopamine (DA) levels were enhanced in α6L9'S NAc slices compared to control, non-transgenic (non-Tg) slices. Extracellular DA levels in both non-Tg and α6L9'S slices were further enhanced in the presence of GBR12909, suggesting intact DA transporter function in both mouse strains. Ongoing α6β2* nAChR activation by acetylcholine plays a role in enhancing DA levels, as α-conotoxin MII completely abolished evoked DA release in α6L9'S slices and decreased spontaneous DA release from striatal synaptosomes. In HPLC experiments, α6L9'S NAc tissue contained significantly more DA, 3,4-dihydroxyphenylacetic acid, and homovanillic acid compared to non-Tg NAc tissue. Serotonin (5-HT), 5-hydroxyindoleacetic acid, and norepinephrine (NE) were unchanged in α6L9'S compared to non-Tg tissue. Western blot analysis revealed increased tyrosine hydroxylase expression in α6L9'S NAc. Overall, these results show that enhanced α6β2* nAChR activity in NAc can stimulate DA production and lead to increased extracellular DA levels. © 2013 International Society for Neurochemistry.

Tissue specific resonance frequencies of water and metabolites within the human brain

NASA Astrophysics Data System (ADS)

Chadzynski, Grzegorz L.; Bender, Benjamin; Groeger, Adriane; Erb, Michael; Klose, Uwe

2011-09-01

Chemical shift imaging (CSI) without water suppression was used to examine tissue-specific resonance frequencies of water and metabolites within the human brain. The aim was to verify if there are any regional differences in those frequencies and to determine the influence of chemical shift displacement in slice-selection direction. Unsuppressed spectra were acquired at 3 T from nine subjects. Resonance frequencies of water and after water signal removal of total choline, total creatine and NAA were estimated. Furthermore, frequency distances between the water and those resonances were calculated. Results were corrected for chemical shift displacement. Frequency distances between water and metabolites were consistent and greater for GM than for WM. The highest value of WM to GM difference (14 ppb) was observed for water to NAA frequency distance. This study demonstrates that there are tissue-specific differences between frequency distances of water and metabolites. Moreover, the influence of chemical shift displacement in slice-selection direction is showed to be negligible.

Tissue specific resonance frequencies of water and metabolites within the human brain.

PubMed

Chadzynski, Grzegorz L; Bender, Benjamin; Groeger, Adriane; Erb, Michael; Klose, Uwe

2011-09-01

Chemical shift imaging (CSI) without water suppression was used to examine tissue-specific resonance frequencies of water and metabolites within the human brain. The aim was to verify if there are any regional differences in those frequencies and to determine the influence of chemical shift displacement in slice-selection direction. Unsuppressed spectra were acquired at 3T from nine subjects. Resonance frequencies of water and after water signal removal of total choline, total creatine and NAA were estimated. Furthermore, frequency distances between the water and those resonances were calculated. Results were corrected for chemical shift displacement. Frequency distances between water and metabolites were consistent and greater for GM than for WM. The highest value of WM to GM difference (14ppb) was observed for water to NAA frequency distance. This study demonstrates that there are tissue-specific differences between frequency distances of water and metabolites. Moreover, the influence of chemical shift displacement in slice-selection direction is showed to be negligible. Copyright © 2011 Elsevier Inc. All rights reserved.

Electroosmotic perfusion of tissue: sampling the extracellular space and quantitative assessment of membrane-bound enzyme activity in organotypic hippocampal slice cultures.

PubMed

Ou, Yangguang; Wu, Juanfang; Sandberg, Mats; Weber, Stephen G

2014-10-01

This review covers recent advances in sampling fluid from the extracellular space of brain tissue by electroosmosis (EO). Two techniques, EO sampling with a single fused-silica capillary and EO push-pull perfusion, have been developed. These tools were used to investigate the function of membrane-bound enzymes with outward-facing active sites, or ectoenzymes, in modulating the activity of the neuropeptides leu-enkephalin and galanin in organotypic-hippocampal-slice cultures (OHSCs). In addition, the approach was used to determine the endogenous concentration of a thiol, cysteamine, in OHSCs. We have also investigated the degradation of coenzyme A in the extracellular space. The approach provides information on ectoenzyme activity, including Michaelis constants, in tissue, which, as far as we are aware, has not been done before. On the basis of computational evidence, EO push-pull perfusion can distinguish ectoenzyme activity with a ~100 μm spatial resolution, which is important for studies of enzyme kinetics in adjacent regions of the rat hippocampus.

Effect of low refocusing angle in T1-weighted spin echo and fast spin echo MRI on low-contrast detectability: a comparative phantom study at 1.5 and 3 Tesla.

PubMed

Sarkar, Subhendra N; Mangosing, Jason L; Sarkar, Pooja R

2013-01-01

MRI tissue contrast is not well preserved at high field. In this work, we used a phantom with known, intrinsic contrast (3.6%) for model tissue pairs to test the effects of low angle refocusing pulses and magnetization transfer from adjacent slices on intrinsic contrast at 1.5 and 3 Tesla. Only T1-weighted spin echo sequences were tested since for such sequences the contrast loss, tissue heating, and image quality degradation at high fields seem to present significant diagnostic and quality issues. We hypothesized that the sources of contrast loss could be attributed to low refocusing angles that do not fulfill the Hahn spin echo conditions or to magnetization transfer effects from adjacent slices in multislice imaging. At 1.5 T the measured contrast was 3.6% for 180° refocusing pulses and 2% for 120° pulses, while at 3 T, it was 4% for 180° and only 1% for 120° refocusing pulses. There was no significant difference between single slice and multislice imaging suggesting little or no role played by magnetization transfer in the phantom chosen. Hence, one may conclude that low angle refocusing pulses not fulfilling the Hahn spin echo conditions are primarily responsible for significant deterioration of T1-weighted spin echo image contrast in high-field MRI.

Relationship between moisture content and electrical impedance of carrot slices during drying

NASA Astrophysics Data System (ADS)

Kertész, Ákos; Hlaváčová, Zuzana; Vozáry, Eszter; Staroňová, Lenka

2015-01-01

Electrical properties of food materials can give information about the inner structure and physiological state of biological tissues. Generally, the process of drying of fruits and vegetables is followed by weight loss. The aim of this study was to measure the impedance spectra of carrot slices during drying and to correlate impedance parameters to moisture content in different drying periods. Cylindrical slices were cut out from the carrot root along the axis. The slices were dried in a Venticell 111 air oven at 50°C. The weight of the slices was measured with a Denver SI-603 electronic analytical and precision balance. The weighing of the samples was performed every 30 min at the beginning of drying and every 60 min after the process. The moisture content of the samples was calculated on wet basis. The magnitude and phase angle of electrical impedance of the slices were measured with HP 4284A and 4285A precision LCR meters in the frequency range from 30 Hz to 1 MHz and from 75 kHz to 30 MHz, respectively, at voltage 1 V. The impedance measurement was performed after weighting. The change in the magnitude of impedance during drying showed a good correlation with the change in the moisture content.

Targeting neurotransmitter receptors with nanoparticles in vivo allows single-molecule tracking in acute brain slices

NASA Astrophysics Data System (ADS)

Varela, Juan A.; Dupuis, Julien P.; Etchepare, Laetitia; Espana, Agnès; Cognet, Laurent; Groc, Laurent

2016-03-01

Single-molecule imaging has changed the way we understand many biological mechanisms, particularly in neurobiology, by shedding light on intricate molecular events down to the nanoscale. However, current single-molecule studies in neuroscience have been limited to cultured neurons or organotypic slices, leaving as an open question the existence of fast receptor diffusion in intact brain tissue. Here, for the first time, we targeted dopamine receptors in vivo with functionalized quantum dots and were able to perform single-molecule tracking in acute rat brain slices. We propose a novel delocalized and non-inflammatory way of delivering nanoparticles (NPs) in vivo to the brain, which allowed us to label and track genetically engineered surface dopamine receptors in neocortical neurons, revealing inherent behaviour and receptor activity regulations. We thus propose a NP-based platform for single-molecule studies in the living brain, opening new avenues of research in physiological and pathological animal models.

Flip-flop method: A new T1-weighted flow-MRI for plants studies.

PubMed

Buy, Simon; Le Floch, Simon; Tang, Ning; Sidiboulenouar, Rahima; Zanca, Michel; Canadas, Patrick; Nativel, Eric; Cardoso, Maida; Alibert, Eric; Dupont, Guillaume; Ambard, Dominique; Maurel, Christophe; Verdeil, Jean-Luc; Bertin, Nadia; Goze-Bac, Christophe; Coillot, Christophe

2018-01-01

The climate warming implies an increase of stress of plants (drought and torrential rainfall). The understanding of plant behavior, in this context, takes a major importance and sap flow measurement in plants remains a key issue for plant understanding. Magnetic Resonance Imaging (MRI) which is well known to be a powerful tool to access water quantity can be used to measure moving water. We describe a novel flow-MRI method which takes advantage of inflow slice sensitivity. The method involves the slice selectivity in the context of multi slice spin echo sequence. Two sequences such as a given slice is consecutively inflow and outflow sensitive are performed, offering the possiblility to perform slow flow sensitive imaging in a quite straigthforward way. The method potential is demonstrated by imaging both a slow flow measurement on a test bench (as low as 10 μm.s-1) and the Poiseuille's profile of xylemian sap flow velocity in the xylematic tissues of a tomato plant stem.

Differentiation of dried sea cucumber products from different geographical areas by surface desorption atmospheric pressure chemical ionization mass spectrometry.

PubMed

Wu, Zhongchen; Chen, Huanwen; Wang, Weiling; Jia, Bin; Yang, Tianlin; Zhao, Zhanfeng; Ding, Jianhua; Xiao, Xuxian

2009-10-28

Without any sample pretreatment, mass spectral fingerprints of 486 dried sea cucumber slices were rapidly recorded in the mass range of m/z 50-800 by using surface desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS). A set of 162 individual sea cucumbers (Apostichopus japonicus Selenka) grown up in 3 different geographical regions (Weihai: 59 individuals, 177 slices; Yantai: 53 individuals, 159 slices; Dalian: 50 individuals, 150 slices;) in north China sea were successfully differentiated according to their habitats both by Principal Components Analysis (PCA) and Soft Independent Modeling of Class Analogy (SIMCA) of the mass spectral raw data, demonstrating that DAPCI-MS is a practically convenient tool for high-throughput differentiation of sea cucumber products. It has been found that the difference between the body wall tissue and the epidermal tissue is heavily dependent on the habitats. The experimental data also show that the roughness of the sample surface contributes to the variance of the signal levels in a certain extent, but such variance does not fail the differentiation of the dried sea cucumber samples.

Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view.

PubMed

Guehrs, Erik; Schneider, Michael; Günther, Christian M; Hessing, Piet; Heitz, Karen; Wittke, Doreen; López-Serrano Oliver, Ana; Jakubowski, Norbert; Plendl, Johanna; Eisebitt, Stefan; Haase, Andrea

2017-03-21

Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches. We quantified cellular uptake of 75 nm diameter citrate stabilized silver NPs (Ag 75 Cit) into an individual human macrophage derived from monocytic THP-1 cells using a FIB/SEM slice and view approach. Cells were treated with 10 μg/ml for 24 h. We investigated a single cell and found in total 3138 ± 722 silver NPs inside this cell. Most of the silver NPs were located in large agglomerates, only a few were found in clusters of fewer than five NPs. Furthermore, we cross-checked our results by using inductively coupled plasma mass spectrometry and could confirm the FIB/SEM results. Our approach based on FIB/SEM slice and view is currently the only one that allows the quantification of the absolute dose of silver NPs in individual cells and at the same time to assess their intracellular distribution at high resolution. We therefore propose to use FIB/SEM slice and view to systematically analyse the cellular uptake of various NPs as a function of size, concentration and incubation time.

Raman microscopy of freeze-dried mouse eyeball-slice in conjunction with the "in vivo cryotechnique".

PubMed

Terada, Nobuo; Ohno, Nobuhiko; Saitoh, Sei; Fujii, Yasuhisa; Ohguro, Hiroshi; Ohno, Shinichi

2007-07-01

The wavelength of Raman-scattered light depends on the molecular composition of the substance. This is the first attempt to acquire Raman spectra of a mouse eyeball removed from a living mouse, in which the eyeball was preserved using the "in vivo cryotechnique" followed by freeze-drying. Eyeballs were cryofixed using a rapid freezing cryotechnique, and then sliced in the cryostat machine. The slices were sandwiched between glass slides, freeze-dried, and analyzed with confocal Raman microscopy. Important areas including various eyeball tissue layers were selected using bright-field microscopy, and then the Raman spectra were obtained at 240 locations. Four typical patterns of Raman spectra were electronically mapped on the specimen images obtained by the bright-field microscopy. Tissue organization was confirmed by embedding the same eyeball slice used for Raman spectra into epoxy resin and the thick sections were prepared with the inverted capsule method. Each Raman spectral pattern represents a different histological layer in the eyeball which was mapped by comparing the images of toluidine blue staining and Raman mapping with different colors. In the choroid and pigment cell layer, the Raman spectrum had two peaks, corresponding to melanin. Some of the peaks of the Raman spectra obtained from the blood vessels in sclera and the photoreceptor layer were similar to those obtained from the purified hemoglobin and rhodopsin proteins, respectively. Our experimental protocol can distinguish different tissue components with Raman microscopy; therefore, this method can be very useful for examining the distribution of a biological structures and/or chemical components in rapidly frozen freeze-dried tissue.

Bioimpedance profiling of the limbs: Update

NASA Astrophysics Data System (ADS)

Ward, L. C.; Essex, T.; Bartlett, M.; Kilbreath, S.; Brookes, D.

2010-04-01

Bioelectrical impedance spectroscopy (BIS) is now commonly used to assess breast cancer-related lymphoedema. Typically, the ratio of impedances of the two arms, determined at zero frequency (Z0), is used as a quantitative index of the presence of excess lymph. Measurement uses skin electrodes spanning the whole limb. However, lymphoedema may be highly localised and may involve changes other than simple fluid accumulation, e.g. increased fat and fibrosis, that also give rise to changes in impedance-related parameters such as capacitance. We have previously reported (13th ICEBI, Graz, 2007) a prototype mobile electrode probe that replaces the distal sense electrode which, when moved proximally along the arm, provides an impedance profile. We report here the further development of this technology to incorporate real-time measurement of impedance integrated with a digital measuring wheel. This allows exact synchronisation of impedance with position on the arm. A commercial BIS instrument (ImpediMed SFB7) was modified to collect impedance (R and Xc) data every msec and the mean impedance computed for each 10-mm slice. The apparent resistivity values for arm tissue were used to calculate slice volumes. These computed volumes were compared to equivalent slice volumes from perometry and DXA. The system is being further validated by correlating slice impedance parameters with lean tissue volume determined by pQCT (StraTec XCT 3000), for multiple positions along the arm. Ultimately, it is hoped that such measurements will not only allow localised tissue volume measurement but will also provide information of tissue composition in conditions such as lymphoedema.

A shape-based statistical method to retrieve 2D TRUS-MR slice correspondence for prostate biopsy

NASA Astrophysics Data System (ADS)

Mitra, Jhimli; Srikantha, Abhilash; Sidibé, Désiré; Martí, Robert; Oliver, Arnau; Lladó, Xavier; Ghose, Soumya; Vilanova, Joan C.; Comet, Josep; Meriaudeau, Fabrice

2012-02-01

This paper presents a method based on shape-context and statistical measures to match interventional 2D Trans Rectal Ultrasound (TRUS) slice during prostate biopsy to a 2D Magnetic Resonance (MR) slice of a pre-acquired prostate volume. Accurate biopsy tissue sampling requires translation of the MR slice information on the TRUS guided biopsy slice. However, this translation or fusion requires the knowledge of the spatial position of the TRUS slice and this is only possible with the use of an electro-magnetic (EM) tracker attached to the TRUS probe. Since, the use of EM tracker is not common in clinical practice and 3D TRUS is not used during biopsy, we propose to perform an analysis based on shape and information theory to reach close enough to the actual MR slice as validated by experts. The Bhattacharyya distance is used to find point correspondences between shape-context representations of the prostate contours. Thereafter, Chi-square distance is used to find out those MR slices where the prostates closely match with that of the TRUS slice. Normalized Mutual Information (NMI) values of the TRUS slice with each of the axial MR slices are computed after rigid alignment and consecutively a strategic elimination based on a set of rules between the Chi-square distances and the NMI leads to the required MR slice. We validated our method for TRUS axial slices of 15 patients, of which 11 results matched at least one experts validation and the remaining 4 are at most one slice away from the expert validations.

A post-reconstruction method to correct cupping artifacts in cone beam breast computed tomography

PubMed Central

Altunbas, M. C.; Shaw, C. C.; Chen, L.; Lai, C.; Liu, X.; Han, T.; Wang, T.

2007-01-01

In cone beam breast computed tomography (CT), scattered radiation leads to nonuniform biasing of CT numbers known as a cupping artifact. Besides being visual distractions, cupping artifacts appear as background nonuniformities, which impair efficient gray scale windowing and pose a problem in threshold based volume visualization/segmentation. To overcome this problem, we have developed a background nonuniformity correction method specifically designed for cone beam breast CT. With this technique, the cupping artifact is modeled as an additive background signal profile in the reconstructed breast images. Due to the largely circularly symmetric shape of a typical breast, the additive background signal profile was also assumed to be circularly symmetric. The radial variation of the background signals were estimated by measuring the spatial variation of adipose tissue signals in front view breast images. To extract adipose tissue signals in an automated manner, a signal sampling scheme in polar coordinates and a background trend fitting algorithm were implemented. The background fits compared with targeted adipose tissue signal value (constant throughout the breast volume) to get an additive correction value for each tissue voxel. To test the accuracy, we applied the technique to cone beam CT images of mastectomy specimens. After correction, the images demonstrated significantly improved signal uniformity in both front and side view slices. The reduction of both intra-slice and inter-slice variations in adipose tissue CT numbers supported our observations. PMID:17822018

Glucose-Stimulated Calcium Dynamics in Islets of Langerhans in Acute Mouse Pancreas Tissue Slices

PubMed Central

Stožer, Andraž; Dolenšek, Jurij; Rupnik, Marjan Slak

2013-01-01

In endocrine cells within islets of Langerhans calcium ions couple cell stimulation to hormone secretion. Since the advent of modern fluorimetry, numerous in vitro studies employing primarily isolated mouse islets have investigated the effects of various secretagogues on cytoplasmic calcium, predominantly in insulin-secreting beta cells. Due to technical limitations, insights of these studies are inherently limited to a rather small subpopulation of outermost cells. The results also seem to depend on various factors, like culture conditions and duration, and are not always easily reconcilable with findings in vivo. The main controversies regard the types of calcium oscillations, presence of calcium waves, and the level of synchronized activity. Here, we set out to combine the in situ acute mouse pancreas tissue slice preparation with noninvasive fluorescent calcium labeling and subsequent confocal laser scanning microscopy to shed new light on the existing controversies utilizing an innovative approach enabling the characterization of responses in many cells from all layers of islets. Our experiments reproducibly showed stable fast calcium oscillations on a sustained plateau rather than slow oscillations as the predominant type of response in acute tissue slices, and that calcium waves are the mechanistic substrate for synchronization of oscillations. We also found indirect evidence that even a large amplitude calcium signal was not sufficient and that metabolic activation was necessary to ensure cell synchronization upon stimulation with glucose. Our novel method helped resolve existing controversies and showed the potential to help answer important physiological questions, making it one of the methods of choice for the foreseeable future. PMID:23358454

Follicle dynamics: visualization and analysis of follicle growth and maturation using murine ovarian tissue culture.

PubMed

Murase, Tomohiko; Iwase, Akira; Komatsu, Kouji; Bayasula; Nakamura, Tomoko; Osuka, Satoko; Takikawa, Sachiko; Goto, Maki; Kotani, Tomomi; Kikkawa, Fumitaka

2018-02-01

To visualize and analyze follicle development in ovarian tissue culture using physiological concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in order to establish an ovarian tissue culture system that enables efficient in vitro growth of follicles. Ovarian tissues from 4-week-old female ICR mice were sliced and cultured. Images of ovarian tissues in culture were obtained at 24-h or 30-min intervals by using a microscope. The area of each follicle observed in the ovarian tissue slices was tracked and analyzed in association with oocyte maturation. We were able to track the development of each follicle using this culture system. Follicle growth was associated with oocyte maturation. Meiotically matured oocytes (MII) were obtained from 33% of all follicles investigated. Approximately, a quarter of follicles (24%) did not grow and resulted in atresia. Follicle dynamics were successfully visualized and analyzed in murine ovarian tissue culture. We were able to obtain mature oocytes from the fully grown follicles in vitro. This culture system would be helpful for efficient in vitro culturing of ovarian tissues.

Trafficking of astrocytic vesicles in hippocampal slices

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

Potokar, Maja; Kreft, Marko; Celica Biomedical Center, Technology Park 24, 1000 Ljubljana

2009-12-25

The increasingly appreciated role of astrocytes in neurophysiology dictates a thorough understanding of the mechanisms underlying the communication between astrocytes and neurons. In particular, the uptake and release of signaling substances into/from astrocytes is considered as crucial. The release of different gliotransmitters involves regulated exocytosis, consisting of the fusion between the vesicle and the plasma membranes. After fusion with the plasma membrane vesicles may be retrieved into the cytoplasm and may continue to recycle. To study the mobility implicated in the retrieval of secretory vesicles, these structures have been previously efficiently and specifically labeled in cultured astrocytes, by exposing livemore » cells to primary and secondary antibodies. Since the vesicle labeling and the vesicle mobility properties may be an artifact of cell culture conditions, we here asked whether the retrieving exocytotic vesicles can be labeled in brain tissue slices and whether their mobility differs to that observed in cell cultures. We labeled astrocytic vesicles and recorded their mobility with two-photon microscopy in hippocampal slices from transgenic mice with fluorescently tagged astrocytes (GFP mice) and in wild-type mice with astrocytes labeled by Fluo4 fluorescence indicator. Glutamatergic vesicles and peptidergic granules were labeled by the anti-vesicular glutamate transporter 1 (vGlut1) and anti-atrial natriuretic peptide (ANP) antibodies, respectively. We report that the vesicle mobility parameters (velocity, maximal displacement and track length) recorded in astrocytes from tissue slices are similar to those reported previously in cultured astrocytes.« less

N-methyl-D-aspartate increases acetylcholine release from rat striatum and cortex: its effect is augmented by choline

NASA Technical Reports Server (NTRS)

Ulus, I. H.; Buyukuysal, R. L.; Wurtman, R. J.

1992-01-01

We examined the effects of N-methyl-D-aspartate (NMDA), a glutamate agonist, and of glutamate itself, on acetylcholine (ACh) release from superfused rat striatal slices. In a Mg(++)-free medium, NMDA (32-1000 microM) as well as glutamate (1 mM) increased basal ACh release by 35 to 100% (all indicated differences, P less than .05), without altering tissue ACh or choline contents. This augmentation was blocked by Mg++ (1.2 mM) or by MK-801 (10 microM). Electrical stimulation (15 Hz, 75 mA) increased ACh release 9-fold (from 400 to 3660 pmol/mg of protein): this was enhanced (to 4850 pmol/mg of protein) by NMDA (100 microM). ACh levels in stimulated slices fell by 50 or 65% depending on the absence or presence of NMDA. The addition of choline (40 microM) increased ACh release both basally (570 pmol/mg of protein) and with electrical stimulation (6900 pmol/mg of protein). In stimulated slices choline acted synergistically with NMDA, raising ACh release to 10,520 pmol/mg of protein. The presence of choline also blocked the fall in tissue ACh. No treatment affected tissue phospholipid or protein levels. NMDA (32-320 microM) also augmented basal ACh release from cortical but not hippocampal slices. Choline efflux from striatal and cortical (but not hippocampal) slices decreased by 34 to 50% in Mg(++)-free medium. These data indicate that NMDA-like drugs may be useful, particularly in combination with choline, to enhance striatal and cortical cholinergic activity. ACh release from rat hippocampus apparently is not affected by NMDA receptors.

Investigation of factors affecting hypothermic pelvic tissue cooling using bio-heat simulation based on MRI-segmented anatomic models.

PubMed

Lin, Yuting; Lin, Wei-Ching; Fwu, Peter T; Shih, Tzu-Ching; Yeh, Lee-Ren; Su, Min-Ying; Chen, Jeon-Hor

2015-10-01

This study applied a simulation method to map the temperature distribution based on magnetic resonance imaging (MRI) of individual patients, and investigated the influence of different pelvic tissue types as well as the choice of thermal property parameters on the efficiency of endorectal cooling balloon (ECB). MR images of four subjects with different prostate sizes and pelvic tissue compositions, including fatty tissue and venous plexus, were analyzed. The MR images acquired using endorectal coil provided a realistic geometry of deformed prostate that resembled the anatomy in the presence of ECB. A single slice with the largest two-dimensional (2D) cross-sectional area of the prostate gland was selected for analysis. The rectal wall, prostate gland, peri-rectal fatty tissue, peri-prostatic fatty tissue, peri-prostatic venous plexus, and urinary bladder were manually segmented. Pennes' bioheat thermal model was used to simulate the temperature distribution dynamics, by using an in-house finite element mesh based solver written in MATLAB. The results showed that prostate size and periprostatic venous plexus were two major factors affecting ECB cooling efficiency. For cases with negligible amount of venous plexus and small prostate, the average temperature in the prostate and neurovascular bundles could be cooled down to 25 °C within 30 min. For cases with abundant venous plexus and large prostate, the temperature could not reach 25 °C at the end of 3 h cooling. Large prostate made the cooling difficult to propagate through. The impact of fatty tissue on cooling effect was small. The filling of bladder with warm urine during the ECB cooling procedure did not affect the temperature in the prostate or NVB. In addition to the 2D simulation, in one case a 3D pelvic model was constructed for volumetric simulation. It was found that the 2D slice with the largest cross-sectional area of prostate had the most abundant venous plexus, and was the most difficult slice to cool, thus it may provide a conservative prediction of the cooling effect. This feasibility study demonstrated that the simulation tool could potentially be used for adjusting the setting of ECB for individual patients during hypothermic radical prostatectomy. Further studies using MR thermometry are required to validate the in silico results obtained using simulation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Investigation of factors affecting hypothermic pelvic tissue cooling using bio-heat simulation based on MRI-segmented anatomic models

PubMed Central

Lin, Yuting; Lin, Wei-Ching; Fwu, Peter T.; Shih, Tzu-Ching; Yeh, Lee-Ren; Su, Min-Ying; Chen, Jeon-Hor

2015-01-01

This study applied a simulation method to map the temperature distribution based on magnetic resonance imaging (MRI) of individual patients, and investigated the influence of different pelvic tissue types as well as the choice of thermal property parameters on the efficiency of endorectal cooling balloon (ECB). MR images of four subjects with different prostate sizes and pelvic tissue compositions, including fatty tissue and venous plexus, were analyzed. The MR images acquired using endorectal coil provided a realistic geometry of deformed prostate that resembled the anatomy in the presence of ECB. A single slice with the largest two-dimensional (2D) cross-sectional area of the prostate gland was selected for analysis. The rectal wall, prostate gland, peri-rectal fatty tissue, peri-prostatic fatty tissue, peri-prostatic venous plexus, and urinary bladder were manually segmented. Pennes’ bioheat thermal model was used to simulate the temperature distribution dynamics, by using an in-house finite element mesh based solver written in Matlab. The results showed that prostate size and periprostatic venous plexus were two major factors affecting ECB cooling efficiency. For cases with negligible amount of venous plexus and small prostate, the averaged temperature in the prostate and neurovascular bundles could be cooled down to 25°C within 30 minutes. For cases with abundant venous plexus and large prostate, the temperature could not reach 25°C at the end of 3 hours cooling. Large prostate made the cooling difficult to propagate through. The impact of fatty tissue on cooling effect was small. The filling of bladder with warm urine during the ECB cooling procedure did not affect the temperature in the prostate or NVB. In addition to the 2D simulation, in one case a 3D pelvic model was constructed for volumetric simulation. It was found that the 2D slice with the largest cross-sectional area of prostate had the most abundant venous plexus, and was the most difficult slice to cool, thus it may provide a conservative prediction of the cooling effect. This feasibility study demonstrated that the simulation tool could potentially be used for adjusting the setting of ECB for individual patients during hypothermic radical prostatectomy. Further studies using MR thermometry are required to validate the in silico results obtained using simulation. PMID:26198131

Desiccation and osmotic stress increase the abundance of mRNA of the tonoplast aquaporin BobTIP26-1 in cauliflower cells.

PubMed

Barrieu, F; Marty-Mazars, D; Thomas, D; Chaumont, F; Charbonnier, M; Marty, F

1999-07-01

Changes in vacuolar structure and the expression at the RNA level of a tonoplast aquaporin (BobTIP26-1) were examined in cauliflower (Brassicaoleracea L. var. botrytis) under water-stress conditions. Gradual drying out of slices of cauliflower floret tissue caused its collapse, with a shrinkage in tissue and cell volumes and an apparent vesiculation of the central vacuole, whereas osmotic stress resulted in plasmolysis with a collapse of the cytoplasm and the central vacuole within. Osmotic stress caused a rapid and substantial increase in BobTIP26 mRNA in slices of floret tissue. Exposure of tissue slices to a regime of desiccation showed a slower but equally large rise in BobTIP26 mRNA followed by a rapid decline upon rehydration. In situ hybridization showed that BobTIP26-2 mRNA is expressed most highly in meristematic and expanding cells of the cauliflower florets and that desiccation strongly increased the expression in those cells and in differentiated cells near the xylem vessels. These data indicate that under water-deficit conditions, expression of the tonoplast aquaporin gene in cauliflower is subject to a precise regulation that can be correlated with important cytological changes in the cells.

Electroosmotic Sampling. Application to Determination of Ectopeptidase Activity in Organotypic Hippocampal Slice Cultures

PubMed Central

Xu, Hongjuan; Guy, Yifat; Hamsher, Amy; Shi, Guoyue; Sandberg, Mats; Weber, Stephen G.

2010-01-01

We hypothesize that peptide-containing solutions pulled through tissue should reveal the presence and activity of peptidases in the tissue. Using the natural ζ-potential in the organotypic hippocampal slice culture (OHSC), physiological fluids can be pulled through the tissue with an electric field. The hydrolysis of the peptides present in the fluid drawn through the tissue can be determined using capillary HPLC with electrochemical detection of the biuret complexes of the peptides following a postcolumn reaction. We have characterized this new sampling method by measuring the flow rate, examining the use of internal standards, and examining cell death caused by sampling. The sampling flow rate ranges from 60 to 150 nL/min with a 150 μm (ID) sampling capillary with an electric field (at the tip of the capillary) from 30 to 60 V/cm. Cell death can be negligible with controlled sampling conditions. Using this sampling approach, we have electroosmotically pulled Leu-enkephalin through OHSCs to identify ectopeptidase activity in the CA3 region. These studies show that a bestatin-sensitive aminopeptidase may be critical for the hydrolysis of exogenous Leu-enkephalin, a neuropeptide present in the CA3 region of OHSCs. PMID:20669992

Irreversible electroporation ablation area enhanced by synergistic high- and low-voltage pulses.

PubMed

Yao, Chenguo; Lv, Yanpeng; Dong, Shoulong; Zhao, Yajun; Liu, Hongmei

2017-01-01

Irreversible electroporation (IRE) produced by a pulsed electric field can ablate tissue. In this study, we achieved an enhancement in ablation area by using a combination of short high-voltage pulses (HVPs) to create a large electroporated area and long low-voltage pulses (LVPs) to ablate the electroporated area. The experiments were conducted in potato tuber slices. Slices were ablated with an array of four pairs of parallel steel electrodes using one of the following four electric pulse protocols: HVP, LVP, synergistic HVP+LVP (SHLVP) or LVP+HVP. Our results showed that the SHLVPs more effectively necrotized tissue than either the HVPs or LVPs, even when the SHLVP dose was the same as or lower than the HVP or LVP doses. The HVP and LVP order mattered and only HVPs+LVPs (SHLVPs) treatments increased the size of the ablation zone because the HVPs created a large electroporated area that was more susceptible to the subsequent LVPs. Real-time temperature change monitoring confirmed that the tissue was non-thermally ablated by the electric pulses. Theoretical calculations of the synergistic effects of the SHLVPs on tissue ablation were performed. Our proposed SHLVP protocol provides options for tissue ablation and may be applied to optimize the current clinical IRE protocols.

Irreversible electroporation ablation area enhanced by synergistic high- and low-voltage pulses

PubMed Central

2017-01-01

Irreversible electroporation (IRE) produced by a pulsed electric field can ablate tissue. In this study, we achieved an enhancement in ablation area by using a combination of short high-voltage pulses (HVPs) to create a large electroporated area and long low-voltage pulses (LVPs) to ablate the electroporated area. The experiments were conducted in potato tuber slices. Slices were ablated with an array of four pairs of parallel steel electrodes using one of the following four electric pulse protocols: HVP, LVP, synergistic HVP+LVP (SHLVP) or LVP+HVP. Our results showed that the SHLVPs more effectively necrotized tissue than either the HVPs or LVPs, even when the SHLVP dose was the same as or lower than the HVP or LVP doses. The HVP and LVP order mattered and only HVPs+LVPs (SHLVPs) treatments increased the size of the ablation zone because the HVPs created a large electroporated area that was more susceptible to the subsequent LVPs. Real-time temperature change monitoring confirmed that the tissue was non-thermally ablated by the electric pulses. Theoretical calculations of the synergistic effects of the SHLVPs on tissue ablation were performed. Our proposed SHLVP protocol provides options for tissue ablation and may be applied to optimize the current clinical IRE protocols. PMID:28253331

Redox Regulation of Epithelial Sodium Channels Examined in Alveolar Type 1 and 2 Cells Patch-clamped in Lung Slice Tissue*

PubMed Central

Helms, My N.; Jain, Lucky; Self, Julie L.; Eaton, Douglas C.

2008-01-01

The alveolar surface of the lung is lined by alveolar type 1 (AT1) and type 2 (AT2) cells. Using single channel patch clamp analysis in lung slice preparations, we are able to uniquely study AT1 and AT2 cells separately from intact lung. We report for the first time the Na+ transport properties of type 2 cells accessed in live lung tissue (as we have done in type 1 cells). Type 2 cells in lung tissue slices express both highly selective cation and nonselective cation channels with average conductances of 8.8 ± 3.2 and 22.5 ± 6.3 picosiemens, respectively. Anion channels with 10-picosiemen conductance are also present in the apical membrane of type 2 cells. Our lung slice studies importantly verify the use of cultured cell model systems commonly used in lung epithelial sodium channel (ENaC) studies. Furthermore, we identify novel functional differences between the cells that make up the alveolar epithelium. One important difference is that exposure to the nitric oxide (NO) donor, PAPA-NONOate (1.5 μm), significantly decreases average ENaC NPo in type 2 cells (from 1.38 ± 0.26 to 0.82 ± 0.16; p < 0.05 and n = 18) but failed to alter ENaC activity in alveolar type 1 cells. Elevating endogenous superoxide (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\mathrm{O}}_{2}^{\\overline{.}}\\end{equation*}\\end{document}) levels with Ethiolat, a superoxide dismutase inhibitor, prevented NO inhibition of ENaC activity in type 2 cells, supporting the novel hypothesis that \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\mathrm{O}}_{2}^{\\overline{.}}\\end{equation*}\\end{document} and NO signaling plays an important role in maintaining lung fluid balance. PMID:18541535

Preparation of Horizontal Slices of Adult Mouse Retina for Electrophysiological Studies.

PubMed

Feigenspan, Andreas; Babai, Norbert Zsolt

2017-01-27

Vertical slice preparations are well established to study circuitry and signal transmission in the adult mammalian retina. The plane of sectioning in these preparations is perpendicular to the retinal surface, making it ideal for the study of radially oriented neurons like photoreceptors and bipolar cells. However, the large dendritic arbors of horizontal cells, wide-field amacrine cells, and ganglion cells are mostly truncated, leaving markedly reduced synaptic activity in these cells. Whereas ganglion cells and displaced amacrine cells can be studied in a whole-mounted preparation of the retina, horizontal cells and amacrine cells located in the inner nuclear layer are only poorly accessible for electrodes in whole retina tissue. To achieve maximum accessibility and synaptic integrity, we developed a horizontal slice preparation of the mouse retina, and studied signal transmission at the synapse between photoreceptors and horizontal cells. Horizontal sectioning allows (1) easy and unambiguous visual identification of horizontal cell bodies for electrode targeting, and (2) preservation of the extended horizontal cell dendritic fields, as a prerequisite for intact and functional cone synaptic input to horizontal cell dendrites. Horizontal cells from horizontal slices exhibited tonic synaptic activity in the dark, and they responded to brief flashes of light with a reduction of inward current and diminished synaptic activity. Immunocytochemical evidence indicates that almost all cones within the dendritic field of a horizontal cell establish synapses with its peripheral dendrites. The horizontal slice preparation is therefore well suited to study the physiological properties of horizontally extended retinal neurons as well as sensory signal transmission and integration across selected synapses.

Clinical feasibility of simultaneous multi-slice imaging with blipped-CAIPI for diffusion-weighted imaging and diffusion-tensor imaging of the brain.

PubMed

Yokota, Hajime; Sakai, Koji; Tazoe, Jun; Goto, Mariko; Imai, Hiroshi; Teramukai, Satoshi; Yamada, Kei

2017-12-01

Background Simultaneous multi-slice (SMS) imaging is starting to be used in clinical situation, although evidence of clinical feasibility is scanty. Purpose To prospectively assess the clinical feasibility of SMS diffusion-weighted imaging (DWI) and diffusion-tensor imaging (DTI) with blipped-controlled aliasing in parallel imaging for brain lesions. Material and Methods The institutional review board approved this study. This study included 156 hyperintense lesions on DWI from 32 patients. A slice acceleration factor of 2 was applied for SMS scans, which allowed shortening of the scan time by 41.3%. The signal-to-noise ratio (SNR) was calculated for brain tissue of a selected slice. The contrast-to-noise ratio (CNR), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were calculated in 36 hyperintense lesions with a diameter of three pixels or more. Visual assessment was performed for all 156 lesions. Tractography of the corticospinal tract of 29 patients was evaluated. The number of tracts and averaged tract length were used for quantitative analysis, and visual assessment was evaluated by grading. Results The SMS scan showed no bias and acceptable 95% limits of agreement compared to conventional scans in SNR, CNR, and ADC on Bland-Altman analyses. Only FA of the lesions was higher in the SMS scan by 9% ( P = 0.016), whereas FA of the surrounding tissues was similar. Quantitative analysis of tractography showed similar values. Visual assessment of DWI hyperintense lesions and tractography also resulted in comparable evaluation. Conclusion SMS imaging was clinically feasible for imaging quality and quantitative values compared with conventional DWI and DTI.

The effect of head size/shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256-slice CT: How can we minimize the risk for deterministic effects?

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

Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis

Purpose: To determine patient-specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low-dose brain perfusion CT studies on a 256-slice CT scanner, and investigate the effect of patient head size/shape, head position during the examination and bowtie filter used on peak tissue doses. Methods: The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual-specific adult head phantoms subjected to the standard low-dose brain perfusion CT on a 256-slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peakmore » tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size/shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye-lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed. Results: The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye-lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x-ray beam. Positioning head phantom off-isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of signal-to-noise ratio mainly to the peripheral region of the phantom. Conclusions: Despite typical peak doses to skin, eye lens, brain, and RBM from the standard low-dose brain perfusion 256-slice CT protocol are well below the corresponding thresholds for the induction of erythema, cataract, cerebrovascular disease, and depression of hematopoiesis, respectively, every effort should be made toward optimization of the procedure and minimization of dose received by these tissues. The current study provides evidence that the use of the narrower bowtie filter available may considerably reduce peak absorbed dose to all above radiosensitive tissues with minimal deterioration in image quality. Considerable reduction in peak eye-lens dose may also be achieved by positioning patient head center a few centimeters above isocenter during the exposure.« less

Comparative effects of chlorpyrifos in wild type and cannabinoid Cb1 receptor knockout mice

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

Baireddy, Praveena; Liu, Jing; Hinsdale, Myron

2011-11-15

Endocannabinoids (eCBs) modulate neurotransmission by inhibiting the release of a variety of neurotransmitters. The cannabinoid receptor agonist WIN 55.212-2 (WIN) can modulate organophosphorus (OP) anticholinesterase toxicity in rats, presumably by inhibiting acetylcholine (ACh) release. Some OP anticholinesterases also inhibit eCB-degrading enzymes. We studied the effects of the OP insecticide chlorpyrifos (CPF) on cholinergic signs of toxicity, cholinesterase activity and ACh release in tissues from wild type (+/+) and cannabinoid CB1 receptor knockout (-/-) mice. Mice of both genotypes (n = 5-6/treatment group) were challenged with CPF (300 mg/kg, 2 ml/kg in peanut oil, sc) and evaluated for functional and neurochemicalmore » changes. Both genotypes exhibited similar cholinergic signs and cholinesterase inhibition (82-95% at 48 h after dosing) in cortex, cerebellum and heart. WIN reduced depolarization-induced ACh release in vitro in hippocampal slices from wild type mice, but had no effect in hippocampal slices from knockouts or in striatal slices from either genotype. Chlorpyrifos oxon (CPO, 100 {mu}M) reduced release in hippocampal slices from both genotypes in vitro, but with a greater reduction in tissues from wild types (21% vs 12%). CPO had no significant in vitro effect on ACh release in striatum. CPF reduced ACh release in hippocampus from both genotypes ex vivo, but reduction was again significantly greater in tissues from wild types (52% vs 36%). In striatum, CPF led to a similar reduction (20-23%) in tissues from both genotypes. Thus, while CB1 deletion in mice had little influence on the expression of acute toxicity following CPF, CPF- or CPO-induced changes in ACh release appeared sensitive to modulation by CB1-mediated eCB signaling in a brain-regional manner. -- Highlights: Black-Right-Pointing-Pointer C57Bl/6 mice showed dose-related cholinergic toxicity following subcutaneous chlorpyrifos exposure. Black-Right-Pointing-Pointer Wild type and cannabinoid CB1 receptor knockout littermates responded similarly to the toxic effects of chlorpyrifos. Black-Right-Pointing-Pointer OP-induced changes in acetylcholine release appeared sensitive to modulation by CB1-mediated endocannabinoid signaling.« less

Serotonin release varies with brain tryptophan levels

NASA Technical Reports Server (NTRS)

Schaechter, Judith D.; Wurtman, Richard J.

1990-01-01

This study examines directly the effects on serotonin release of varying brain tryptophan levels within the physiologic range. It also addresses possible interactions between tryptophan availability and the frequency of membrane depolarization in controlling serotonin release. We demonstrate that reducing tryptophan levels in rat hypothalamic slices (by superfusing them with medium supplemented with 100 microM leucine) decreases tissue serotonin levels as well as both the spontaneous and the electrically-evoked serotonin release. Conversely, elevating tissue tryptophan levels (by superfusing slices with medium supplemented with 2 microM tryptophan) increases both the tissue serotonin levels and the serotonin release. Serotonin release was found to be affected independently by the tryptophan availability and the frequency of electrical field-stimulation (1-5 Hz), since increasing both variables produced nearly additive increases in release. These observations demonstrate for the first time that both precursor-dependent elevations and reductions in brain serotonin levels produce proportionate changes in serotonin release, and that the magnitude of the tryptophan effect is unrelated to neuronal firing frequency. The data support the hypothesis that serotonin release is proportionate to intracellular serotonin levels.

Cryopreserved Human Precision-Cut Lung Slices as a Bioassay for Live Tissue Banking. A Viability Study of Bronchodilation with Bitter-Taste Receptor Agonists

PubMed Central

Bai, Yan; Krishnamoorthy, Nandini; Patel, Kruti R.; Rosas, Ivan; Ai, Xingbin

2016-01-01

Human precision-cut lung slices (hPCLSs) provide a unique ex vivo model for translational research. However, the limited and unpredictable availability of human lung tissue greatly impedes their use. Here, we demonstrate that cryopreservation of hPCLSs facilitates banking of live human lung tissue for routine use. Our results show that cryopreservation had little effect on overall cell viability and vital functions of immune cells, including phagocytes and T lymphocytes. In addition, airway contraction and relaxation in response to specific agonists and antagonists, respectively, were unchanged after cryopreservation. At the subcellular level, cryopreserved hPCLSs maintained Ca2+-dependent regulatory mechanisms for the control of airway smooth muscle cell contractility. To exemplify the use of cryopreserved hPCLSs in smooth muscle research, we provide evidence that bitter-taste receptor (TAS2R) agonists relax airways by blocking Ca2+ oscillations in airway smooth muscle cells. In conclusion, the banking of cryopreserved hPCLSs provides a robust bioassay for translational research of lung physiology and disease. PMID:26550921

Electroosmotic perfusion of tissue: sampling the extracellular space and quantitative assessment of membrane-bound enzyme activity in organotypic hippocampal slice cultures

PubMed Central

Ou, Yangguang; Wu, Juanfang; Sandberg, Mats

2014-01-01

This review covers recent advances in sampling fluid from the extracellular space of brain tissue by electroosmosis (EO). Two techniques, EO sampling with a single fused-silica capillary and EO push–pull perfusion, have been developed. These tools were used to investigate the function of membrane-bound enzymes with outward-facing active sites, or ectoenzymes, in modulating the activity of the neuropeptides leu-enkephalin and galanin in organotypic-hippocampal-slice cultures (OHSCs). In addition, the approach was used to determine the endogenous concentration of a thiol, cysteamine, in OHSCs. We have also investigated the degradation of coenzyme A in the extracellular space. The approach provides information on ectoenzyme activity, including Michaelis constants, in tissue, which, as far as we are aware, has not been done before. On the basis of computational evidence, EO push–pull perfusion can distinguish ectoenzyme activity with a ~100 µm spatial resolution, which is important for studies of enzyme kinetics in adjacent regions of the rat hippocampus. PMID:25168111

Cryopreserved Human Precision-Cut Lung Slices as a Bioassay for Live Tissue Banking. A Viability Study of Bronchodilation with Bitter-Taste Receptor Agonists.

PubMed

Bai, Yan; Krishnamoorthy, Nandini; Patel, Kruti R; Rosas, Ivan; Sanderson, Michael J; Ai, Xingbin

2016-05-01

Human precision-cut lung slices (hPCLSs) provide a unique ex vivo model for translational research. However, the limited and unpredictable availability of human lung tissue greatly impedes their use. Here, we demonstrate that cryopreservation of hPCLSs facilitates banking of live human lung tissue for routine use. Our results show that cryopreservation had little effect on overall cell viability and vital functions of immune cells, including phagocytes and T lymphocytes. In addition, airway contraction and relaxation in response to specific agonists and antagonists, respectively, were unchanged after cryopreservation. At the subcellular level, cryopreserved hPCLSs maintained Ca(2+)-dependent regulatory mechanisms for the control of airway smooth muscle cell contractility. To exemplify the use of cryopreserved hPCLSs in smooth muscle research, we provide evidence that bitter-taste receptor (TAS2R) agonists relax airways by blocking Ca(2+) oscillations in airway smooth muscle cells. In conclusion, the banking of cryopreserved hPCLSs provides a robust bioassay for translational research of lung physiology and disease.

Longitudinal analysis on human cervical tissue using optical coherence tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Gan, Yu; Yao, Wang; Myers, Kristin M.; Vink, Joy-Sarah Y.; Wapner, Ronald J.; Hendon, Christine P.

2017-02-01

Uterine cervical collagen fiber network is vital to the normal cervical function in pregnancy. Previously, we presented an orientation estimation method to enable dispersion analysis on a single axial slice of human cervical tissue obtained from the upper half of cervix using optical coherence tomography (OCT). How the collagen fiber network structure changes from the internal os (top of the cervix which meets the uterus) to external os (bottom of cervix which extends into the vagina), remains unknown due to depth penetration limitations of OCT. To establish a collagen fiber directionality "map" of the entire cervix, we imaged serial axial slices of human NP (n=11) and PG (n=2) cervical tissue obtained from the internal to external os using Institutional Review Board approved protocols at Columbia University Medical Center. Each slice was divided into four quadrants. In each quadrant, we stitched multiple overlapped OCT volumes and analyzed the en face images that were parallel to the surface. A pixel-wise directionality map was generated. We analyzed fiber trend by measuring the mean angles and quantified dispersion by calculating the standard deviation of the fiber direction over a region of 400 μm × 400 μm. For the initial four samples, our analysis confirms a circumferential fiber pattern in the outer region of slices at all depths. We found that the standard deviation close to internal os showed no significance to the standard deviation close to external os (p>0.05), indicating comparable dispersion.

Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices.

PubMed

Israel, Jean-Marc; Oliet, Stéphane H; Ciofi, Philippe

2016-01-01

Hypothalamic neurohormones are released in a pulsatile manner. The mechanisms of this pulsatility remain poorly understood and several hypotheses are available, depending upon the neuroendocrine system considered. Among these systems, hypothalamo-neurohypophyseal magnocellular neurons have been early-considered models, as they typically display an electrical activity consisting of bursts of action potentials that is optimal for the release of boluses of the neurohormones oxytocin and vasopressin. The cellular mechanisms underlying this bursting behavior have been studied in vitro, using either acute slices of the adult hypothalamus, or organotypic cultures of neonatal hypothalamic tissue. We have recently proposed, from experiments in organotypic cultures, that specific central pattern generator networks, upstream of magnocellular neurons, determine their bursting activity. Here, we have tested whether a similar hypothesis can be derived from in vitro experiments in acute slices of the adult hypothalamus. To this aim we have screened our electrophysiological recordings of the magnocellular neurons, previously obtained from acute slices, with an analysis of autocorrelation of action potentials to detect a rhythmic drive as we recently did for organotypic cultures. This confirmed that the bursting behavior of magnocellular neurons is governed by central pattern generator networks whose rhythmic drive, and thus probably integrity, is however less satisfactorily preserved in the acute slices from adult brains.

Comparison of Image Processing Techniques for Nonviable Tissue Quantification in Late Gadolinium Enhancement Cardiac Magnetic Resonance Images.

PubMed

Carminati, M Chiara; Boniotti, Cinzia; Fusini, Laura; Andreini, Daniele; Pontone, Gianluca; Pepi, Mauro; Caiani, Enrico G

2016-05-01

The aim of this study was to compare the performance of quantitative methods, either semiautomated or automated, for left ventricular (LV) nonviable tissue analysis from cardiac magnetic resonance late gadolinium enhancement (CMR-LGE) images. The investigated segmentation techniques were: (i) n-standard deviations thresholding; (ii) full width at half maximum thresholding; (iii) Gaussian mixture model classification; and (iv) fuzzy c-means clustering. These algorithms were applied either in each short axis slice (single-slice approach) or globally considering the entire short-axis stack covering the LV (global approach). CMR-LGE images from 20 patients with ischemic cardiomyopathy were retrospectively selected, and results from each technique were assessed against manual tracing. All methods provided comparable performance in terms of accuracy in scar detection, computation of local transmurality, and high correlation in scar mass compared with the manual technique. In general, no significant difference between single-slice and global approach was noted. The reproducibility of manual and investigated techniques was confirmed in all cases with slightly lower results for the nSD approach. Automated techniques resulted in accurate and reproducible evaluation of LV scars from CMR-LGE in ischemic patients with performance similar to the manual technique. Their application could minimize user interaction and computational time, even when compared with semiautomated approaches.

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

Stewart, D.J.; Laansoo, M.; Sen, A.K.

Slices of rat submandibular gland were preloaded with /sup 86/Rb, an isotope that can substitute for K/sup +/ in the K/sup +/ release process. The efflux of /sup 86/Rb was monitored in a superfusion apparatus that efficiently removed the /sup 86/Rb as it exited from the tissue slices. Carbachol and the calcium ionophore A23187 activated a calcium-dependent increase in /sup 86/Rb efflux. Dibutyryl cGMP had no detectable effect on /sup 86/Rb efflux in contrast to its activation of ouabain-sensitive uptake of /sup 86/Rb observed in an earlier study. The stimulated release of /sup 86/Rb was not dependent on the presencemore » of either sodium or chloride ion. When /sup 86/Rb efflux was stimulated by carbachol, the efflux rate returned toward the basal rate after a few minutes of exposure to carbachol in the medium. If ouabain was then introduced into the superfusate, a large increase in efflux was stimulated. In the absence of carbachol, only a small increase in /sup 86/Rb efflux was stimulated by ouabain. The effect of ouabain indicates that there was a substantial recycling of /sup 86/Rb between the release and uptake processes in the extracellular space of the tissue slice. The significance of this observation is discussed.« less

Computerized detection of breast lesions in multi-centre and multi-instrument DCE-MR data using 3D principal component maps and template matching

NASA Astrophysics Data System (ADS)

Ertas, Gokhan; Doran, Simon; Leach, Martin O.

2011-12-01

In this study, we introduce a novel, robust and accurate computerized algorithm based on volumetric principal component maps and template matching that facilitates lesion detection on dynamic contrast-enhanced MR. The study dataset comprises 24 204 contrast-enhanced breast MR images corresponding to 4034 axial slices from 47 women in the UK multi-centre study of MRI screening for breast cancer and categorized as high risk. The scans analysed here were performed on six different models of scanner from three commercial vendors, sited in 13 clinics around the UK. 1952 slices from this dataset, containing 15 benign and 13 malignant lesions, were used for training. The remaining 2082 slices, with 14 benign and 12 malignant lesions, were used for test purposes. To prevent false positives being detected from other tissues and regions of the body, breast volumes are segmented from pre-contrast images using a fast semi-automated algorithm. Principal component analysis is applied to the centred intensity vectors formed from the dynamic contrast-enhanced T1-weighted images of the segmented breasts, followed by automatic thresholding to eliminate fatty tissues and slowly enhancing normal parenchyma and a convolution and filtering process to minimize artefacts from moderately enhanced normal parenchyma and blood vessels. Finally, suspicious lesions are identified through a volumetric sixfold neighbourhood connectivity search and calculation of two morphological features: volume and volumetric eccentricity, to exclude highly enhanced blood vessels, nipples and normal parenchyma and to localize lesions. This provides satisfactory lesion localization. For a detection sensitivity of 100%, the overall false-positive detection rate of the system is 1.02/lesion, 1.17/case and 0.08/slice, comparing favourably with previous studies. This approach may facilitate detection of lesions in multi-centre and multi-instrument dynamic contrast-enhanced breast MR data.

Functional Stem Cell Integration into Neural Networks Assessed by Organotypic Slice Cultures.

PubMed

Forsberg, David; Thonabulsombat, Charoensri; Jäderstad, Johan; Jäderstad, Linda Maria; Olivius, Petri; Herlenius, Eric

2017-08-14

Re-formation or preservation of functional, electrically active neural networks has been proffered as one of the goals of stem cell-mediated neural therapeutics. A primary issue for a cell therapy approach is the formation of functional contacts between the implanted cells and the host tissue. Therefore, it is of fundamental interest to establish protocols that allow us to delineate a detailed time course of grafted stem cell survival, migration, differentiation, integration, and functional interaction with the host. One option for in vitro studies is to examine the integration of exogenous stem cells into an existing active neural network in ex vivo organotypic cultures. Organotypic cultures leave the structural integrity essentially intact while still allowing the microenvironment to be carefully controlled. This allows detailed studies over time of cellular responses and cell-cell interactions, which are not readily performed in vivo. This unit describes procedures for using organotypic slice cultures as ex vivo model systems for studying neural stem cell and embryonic stem cell engraftment and communication with CNS host tissue. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Feasibility of Quantifying Arterial Cerebral Blood Volume Using Multiphase Alternate Ascending/Descending Directional Navigation (ALADDIN).

PubMed

Kim, Ki Hwan; Choi, Seung Hong; Park, Sung-Hong

2016-01-01

Arterial cerebral blood volume (aCBV) is associated with many physiologic and pathologic conditions. Recently, multiphase balanced steady state free precession (bSSFP) readout was introduced to measure labeled blood signals in the arterial compartment, based on the fact that signal difference between labeled and unlabeled blood decreases with the number of RF pulses that is affected by blood velocity. In this study, we evaluated the feasibility of a new 2D inter-slice bSSFP-based arterial spin labeling (ASL) technique termed, alternate ascending/descending directional navigation (ALADDIN), to quantify aCBV using multiphase acquisition in six healthy subjects. A new kinetic model considering bSSFP RF perturbations was proposed to describe the multiphase data and thus to quantify aCBV. Since the inter-slice time delay (TD) and gap affected the distribution of labeled blood spins in the arterial and tissue compartments, we performed the experiments with two TDs (0 and 500 ms) and two gaps (300% and 450% of slice thickness) to evaluate their roles in quantifying aCBV. Comparison studies using our technique and an existing method termed arterial volume using arterial spin tagging (AVAST) were also separately performed in five subjects. At 300% gap or 500-ms TD, significant tissue perfusion signals were demonstrated, while tissue perfusion signals were minimized and arterial signals were maximized at 450% gap and 0-ms TD. ALADDIN has an advantage of visualizing bi-directional flow effects (ascending/descending) in a single experiment. Labeling efficiency (α) of inter-slice blood flow effects could be measured in the superior sagittal sinus (SSS) (20.8±3.7%.) and was used for aCBV quantification. As a result of fitting to the proposed model, aCBV values in gray matter (1.4-2.3 mL/100 mL) were in good agreement with those from literature. Our technique showed high correlation with AVAST, especially when arterial signals were accentuated (i.e., when TD = 0 ms) (r = 0.53). The bi-directional perfusion imaging with multiphase ALADDIN approach can be an alternative to existing techniques for quantification of aCBV.

Influence of medium-chain triglycerides on lipid metabolism in the rat.

PubMed

Leveille, G A; Pardini, R S; Tillotson, J A

1967-07-01

Lipid metabolism was studied in rats fed diets containing corn oil, coconut oil, or medium-chain triglyceride (MCT), a glyceride mixture containing fatty acids of 8 and 10 carbons in length. The ingestion of MCT-supplemented, cholesterolfree diets depressed plasma and liver total lipids and cholesterol as compared with corn oil-supplemented diets. In rats fed cholesterol-containing diets, plasma cholesterol levels were not influenced by dietary MCT, but liver cholesterol levels were significantly lower than in animals fed corn oil. In vitro cholesterol synthesis from acetate-1-(14)C was lower in liver slices of rats that consumed MCT than in similar preparations from corn oil-fed rats. Studies of fatty acid carboxyl labeling from acetate-1-(14)C and the conversion of palmitate-1-(14)C to C(18) acids by liver slices showed that chain-lengthening activity is greater in the liver tissue of rats fed MCT than in the liver of animals fed corn oil. The hepatic fatty acid desaturation mechanisms, evaluated by measuring the conversion of stearate-2-(14)C to oleate, was also enhanced by feeding MCT.Adipose tissue of rats fed MCT converts acetate-1-(14)C to fatty acids at a much faster rate than does tissue from animals fed corn oil. Evidence is presented to show that the enhanced incorporation of acetate into fatty acids by the adipose tissue of rats fed MCT represents de novo synthesis of fatty acids and not chain-lengthening activity. Data are also presented on the fatty acid composition of plasma, liver, and adipose tissue lipids of rats fed the different fats under study.

Representation of deformable motion for compression of dynamic cardiac image data

NASA Astrophysics Data System (ADS)

Weinlich, Andreas; Amon, Peter; Hutter, Andreas; Kaup, André

2012-02-01

We present a new approach for efficient estimation and storage of tissue deformation in dynamic medical image data like 3-D+t computed tomography reconstructions of human heart acquisitions. Tissue deformation between two points in time can be described by means of a displacement vector field indicating for each voxel of a slice, from which position in the previous slice at a fixed position in the third dimension it has moved to this position. Our deformation model represents the motion in a compact manner using a down-sampled potential function of the displacement vector field. This function is obtained by a Gauss-Newton minimization of the estimation error image, i. e., the difference between the current and the deformed previous slice. For lossless or lossy compression of volume slices, the potential function and the error image can afterwards be coded separately. By assuming deformations instead of translational motion, a subsequent coding algorithm using this method will achieve better compression ratios for medical volume data than with conventional block-based motion compensation known from video coding. Due to the smooth prediction without block artifacts, particularly whole-image transforms like wavelet decomposition as well as intra-slice prediction methods can benefit from this approach. We show that with discrete cosine as well as with Karhunen-Lo`eve transform the method can achieve a better energy compaction of the error image than block-based motion compensation while reaching approximately the same prediction error energy.

Fat quantification and analysis of lung transplant patients on unenhanced chest CT images based on standardized anatomic space

NASA Astrophysics Data System (ADS)

Tong, Yubing; Udupa, Jayaram K.; Torigian, Drew A.; Wu, Caiyun; Christie, Jason; Lederer, David J.

2016-03-01

Chest fat estimation is important for identifying high-risk lung transplant candidates. In this paper, an approach to chest fat quantification based on a recently formulated concept of standardized anatomic space (SAS) is presented. The goal of this paper is to seek answers to the following questions related to chest fat quantification on single slice versus whole volume CT, which have not been addressed in the literature. What level of correlation exists between total chest fat volume and fat areas measured on single abdominal and thigh slices? What is the anatomic location in the chest where maximal correlation of fat area with fat volume can be expected? Do the components of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) have the same area-to-volume correlative behavior or do they differ? The SAS approach includes two steps: calibration followed by transformation which will map the patient slice locations non-linearly to SAS. The optimal slice locations found for SAT and VAT based on SAS are different and at the mid-level of the T8 vertebral body for SAT and mid-level of the T7 vertebral body for VAT. Fat volume and area on optimal slices for SAT and VAT are correlated with Pearson correlation coefficients of 0.97 and 0.86, respectively. The correlation of chest fat volume with abdominal and thigh fat areas is weak to modest.

Annulus Fibrosus Can Strip Hyaline Cartilage End Plate from Subchondral Bone: A Study of the Intervertebral Disk in Tension.

PubMed

Balkovec, Christian; Adams, Michael A; Dolan, Patricia; McGill, Stuart M

2015-10-01

Study Design Biomechanical study on cadaveric spines. Objective Spinal bending causes the annulus to pull vertically (axially) on the end plate, but failure mechanisms in response to this type of loading are poorly understood. Therefore, the objective of this study was to identify the weak point of the intervertebral disk in tension. Methods Cadaveric motion segments (aged 79 to 88 years) were dissected to create midsagittal blocks of tissue, with ∼10 mm of bone superior and inferior to the disk. From these blocks, 14 bone-disk-bone slices (average 4.8 mm thick) were cut in the frontal plane. Each slice was gripped by its bony ends and stretched to failure at 1 mm/s. Mode of failure was recorded using a digital camera. Results Of the 14 slices, 10 failed by the hyaline cartilage being peeled off the subchondral bone, with the failure starting opposite the lateral annulus and proceeding medially. Two slices failed by rupturing of the trabecular bone, and a further two failed in the annulus. Conclusions The hyaline cartilage-bone junction is the disk's weak link in tension. These findings provide a plausible mechanism for the appearance of bone and cartilage fragments in herniated material. Stripping cartilage from the bony end plate would result in the herniated mass containing relatively stiff cartilage that does not easily resorb.

Immunopathology of experimental Chagas' disease: binding of T cells to Trypanosoma cruzi-infected heart tissue.

PubMed Central

Mortatti, R C; Maia, L C; de Oliveira, A V; Munk, M E

1990-01-01

The immunopathology of Chagas' disease was studied in the experimental model of chronic infection in C57BL/10JT or mice. Sublethal infection with Trypanosoma cruzi, Y strain, induced specific antibodies and a delayed hypersensitivity response to parasite antigens. Mice developed chronic chagasic myocarditis but not skeletal muscle myositis. Binding of T cells to infected heart tissue was investigated during short-term cocultivation of lymphocytes with heart cryostat sections. T cells from infected mice and from normal controls bound equally to myocardium and liver sections from both infected and normal mice. A search in depth was attempted with cells heavily tagged with 99mTc. Labeled T cells from chagasic mice bound to both normal and infected myocardium slices. 99mTc-labeled T cells from controls gave the same binding values. Glass-adherent spleen cells behaved identically to T cells. Prior treatment of the tissue with serum from chronically infected mice did not increase the number of binding cells. Peritoneal macrophages tagged with 99mTc-sulfur colloid also bound to infected myocardium slices. The binding of macrophages was not changed by pretreatment of infected tissue with anti-T, cruzi antibodies. In short, this work did not detect any population of T cells or macrophages which could bind specifically to infected heart tissue to initiate an autoreactive process. Images PMID:2228230

In-vitro Thermal Maps to Characterize Human Dental Enamel and Dentin.

PubMed

Lancaster, Paula; Brettle, David; Carmichael, Fiona; Clerehugh, Val

2017-01-01

The crown of a human tooth has an outer layer of highly-mineralized tissue called enamel, beneath which is dentin, a less-mineralized tissue which forms the bulk of the tooth-crown and root. The composition and structure of enamel and dentin are different, resulting in different thermal properties. This gives an opportunity to characterize enamel and dentin from their thermal properties and to visually present the findings as a thermal map. The thermal properties of demineralized enamel and dentin may also be sufficiently different from sound tissue to be seen on a thermal map, underpinning future thermal assessment of caries. The primary aim of this novel study was to produce a thermal map of a sound, human tooth-slice to visually characterize enamel and dentin. The secondary aim was to map a human tooth-slice with demineralized enamel and dentin to consider future diagnostic potential of thermal maps for caries-detection. Two human slices of teeth, one sound and one demineralized from a natural carious lesion, were cooled on ice, then transferred to a hotplate at 30°C where the rewarming-sequence was captured by an infra-red thermal camera. Calculation of thermal diffusivity and thermal conductivity was undertaken, and two methods of data-processing used customized software to produce thermal maps from the thermal characteristic-time-to-relaxation and heat-exchange. The two types of thermal maps characterized enamel and dentin. In addition, sound and demineralized enamel and dentin were distinguishable within both maps. This supports thermal assessment of caries and requires further investigation on a whole tooth.

Preparation of organotypic brain slice cultures for the study of Alzheimer’s disease

PubMed Central

Croft, Cara L.; Noble, Wendy

2018-01-01

Alzheimer's disease, the most common cause of dementia, is a progressive neurodegenerative disorder characterised by amyloid-beta deposits in extracellular plaques, intracellular neurofibrillary tangles of aggregated tau, synaptic dysfunction and neuronal death. There are no cures for AD and current medications only alleviate some disease symptoms. Transgenic rodent models to study Alzheimer’s mimic features of human disease such as age-dependent accumulation of abnormal beta-amyloid and tau, synaptic dysfunction, cognitive deficits and neurodegeneration. These models have proven vital for improving our understanding of the molecular mechanisms underlying AD and for identifying promising therapeutic approaches. However, modelling neurodegenerative disease in animals commonly involves aging animals until they develop harmful phenotypes, often coupled with invasive procedures. In vivo studies are also resource, labour, time and cost intensive. We have developed a novel organotypic brain slice culture model to study Alzheimer’ disease which brings the potential of substantially reducing the number of rodents used in dementia research from an estimated 20,000 per year. We obtain 36 brain slices from each mouse pup, considerably reducing the numbers of animals required to investigate multiple stages of disease. This tractable model also allows the opportunity to modulate multiple pathways in tissues from a single animal. We believe that this model will most benefit dementia researchers in the academic and drug discovery sectors. We validated the slice culture model against aged mice, showing that the molecular phenotype closely mimics that displayed in vivo, albeit in an accelerated timescale. We showed beneficial outcomes following treatment of slices with agents previously shown to have therapeutic effects in vivo, and we also identified new mechanisms of action of other compounds. Thus, organotypic brain slice cultures from transgenic mouse models expressing Alzheimer’s disease-related genes may provide a valid and sensitive replacement for in vivo studies that do not involve behavioural analysis. PMID:29904599

Data-driven sampling method for building 3D anatomical models from serial histology

NASA Astrophysics Data System (ADS)

Salunke, Snehal Ulhas; Ablove, Tova; Danforth, Theresa; Tomaszewski, John; Doyle, Scott

2017-03-01

In this work, we investigate the effect of slice sampling on 3D models of tissue architecture using serial histopathology. We present a method for using a single fully-sectioned tissue block as pilot data, whereby we build a fully-realized 3D model and then determine the optimal set of slices needed to reconstruct the salient features of the model objects under biological investigation. In our work, we are interested in the 3D reconstruction of microvessel architecture in the trigone region between the vagina and the bladder. This region serves as a potential avenue for drug delivery to treat bladder infection. We collect and co-register 23 serial sections of CD31-stained tissue images (6 μm thick sections), from which four microvessels are selected for analysis. To build each model, we perform semi-automatic segmentation of the microvessels. Subsampled meshes are then created by removing slices from the stack, interpolating the missing data, and re-constructing the mesh. We calculate the Hausdorff distance between the full and subsampled meshes to determine the optimal sampling rate for the modeled structures. In our application, we found that a sampling rate of 50% (corresponding to just 12 slices) was sufficient to recreate the structure of the microvessels without significant deviation from the fullyrendered mesh. This pipeline effectively minimizes the number of histopathology slides required for 3D model reconstruction, and can be utilized to either (1) reduce the overall costs of a project, or (2) enable additional analysis on the intermediate slides.

Biomedical terahertz imaging with a quantum cascade laser

NASA Astrophysics Data System (ADS)

Kim, Seongsin M.; Hatami, Fariba; Harris, James S.; Kurian, Allison W.; Ford, James; King, Douglas; Scalari, Giacomo; Giovannini, Marcella; Hoyler, Nicolas; Faist, Jerome; Harris, Geoff

2006-04-01

We present biomedical imaging using a single frequency terahertz imaging system based on a low threshold quantum cascade laser emitting at 3.7THz (λ=81μm). With a peak output power of 4mW, coherent terahertz radiation and detection provide a relatively large dynamic range and high spatial resolution. We study image contrast based on water/fat content ratios in different tissues. Terahertz transmission imaging demonstrates a distinct anatomy in a rat brain slice. We also demonstrate malignant tissue contrast in an image of a mouse liver with developed tumors, indicating potential use of terahertz imaging for probing cancerous tissues.

Breast Milk Jaundice: Effect of 3α 20β-pregnanediol on Bilirubin Conjugation by Human Liver

PubMed Central

Adlard, B. P. F.; Lathe, G. H.

1970-01-01

The effect of 3α,20β-pregnanediol and other steroids on bilirubin conjugation was examined using liver tissue from human and four other species. Neither 3α,20β-pregnanediol nor 3α,20β-pregnanediol inhibited conjugation by human liver slices or by solubilized human liver microsomes. 3α,20β-pregnanediol is unlikely to be the inhibitor causing breast milk jaundice. Oestriol inhibited conjugation by human liver slices. A comparison of species indicated that the response of the human liver slice system to steroids resembles that of the rabbit and guinea-pig rather than the rat or mouse. PMID:4246186

Gunshot energy transfer profile in ballistic gelatine, determined with computed tomography using the total crack length method.

PubMed

Bolliger, Stephan A; Thali, Michael J; Bolliger, Michael J; Kneubuehl, Beat P

2010-11-01

By measuring the total crack lengths (TCL) along a gunshot wound channel simulated in ordnance gelatine, one can calculate the energy transferred by a projectile to the surrounding tissue along its course. Visual quantitative TCL analysis of cut slices in ordnance gelatine blocks is unreliable due to the poor visibility of cracks and the likely introduction of secondary cracks resulting from slicing. Furthermore, gelatine TCL patterns are difficult to preserve because of the deterioration of the internal structures of gelatine with age and the tendency of gelatine to decompose. By contrast, using computed tomography (CT) software for TCL analysis in gelatine, cracks on 1-cm thick slices can be easily detected, measured and preserved. In this, experiment CT TCL analyses were applied to gunshots fired into gelatine blocks by three different ammunition types (9-mm Luger full metal jacket, .44 Remington Magnum semi-jacketed hollow point and 7.62 × 51 RWS Cone-Point). The resulting TCL curves reflected the three projectiles' capacity to transfer energy to the surrounding tissue very accurately and showed clearly the typical energy transfer differences. We believe that CT is a useful tool in evaluating gunshot wound profiles using the TCL method and is indeed superior to conventional methods applying physical slicing of the gelatine.

In Situ Activation of Antigen-Specific CD8+ T Cells in the Presence of Antigen in Organotypic Brain Slices1

PubMed Central

Ling, Changying; Verbny, Yakov I.; Banks, Matthew I.; Sandor, Matyas; Fabry, Zsuzsanna

2012-01-01

The activation of Ag-specific T cells locally in the CNS could potentially contribute to the development of immune-mediated brain diseases. We addressed whether Ag-specific T cells could be stimulated in the CNS in the absence of peripheral lymphoid tissues by analyzing Ag-specific T cell responses in organotypic brain slice cultures. Organotypic brain slice cultures were established 1 h after intracerebral OVA Ag microinjection. We showed that when OVA-specific CD8+ T cells were added to Ag-containing brain slices, these cells became activated and migrated into the brain to the sites of their specific Ags. This activation of OVA-specific T cells was abrogated by the deletion of CD11c+ cells from the brain slices of the donor mice. These data suggest that brain-resident CD11c+ cells stimulate Ag-specific naive CD8+ T cells locally in the CNS and may contribute to immune responses in the brain. PMID:18523307

Apparent diffusion coefficient of the normal human brain for various experimental conditions

NASA Astrophysics Data System (ADS)

Moraru, Luminita; Dimitrievici, Lucian

2017-01-01

Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) is being increasingly used to assess both brain tissues and cerebrospinal fluid integrity. In this paper we study inter-site reproducibility of the apparent diffusion coefficient values for the main cerebral tissues such as gray matter, white matter and into cerebrospinal fluid and for three different stacks of slices that were spaced at L = 79.8, 84.9 and 90 mm. We assessed the impact of the attenuation factor and diffusion gradient on the results reproducibility.

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

Garg, L.C.; McArdle, S.; Crews, F.T.

The release of inositol phosphates (IP) from phosphoinositides (PI) by carbachol was studied in the tissue slices from cortex (C), outer medulla (OM) and inner medulla (IM) of rabbit kidneys. The method involved the incubation of the slices with (/sup 3/H)inositol for its incorporation into the PI and measurement of the release of IP in presence of lithium which prevents dephosphorylation of IP. The results of (/sup 3/H)IP formation are expressed as % of total (/sup 3/H)inositol incorporation in the tissue. No significant effect of carbachol was found on the release of IP in the C. The drug produced amore » 48% increase in IP release in the OM. In the IM, carbachol produced a concentration dependent increase in IP release with a maximum of 772% at 1 mM. The release of IP in the IM by 1 mM carbachol was completely blocked by 1 ..mu..M atropine. Our results indicate that IP release by carbachol is due to activation of muscarinic receptors in the IM of the rabbit kidney.« less

Image segmentation and 3D visualization for MRI mammography

NASA Astrophysics Data System (ADS)

Li, Lihua; Chu, Yong; Salem, Angela F.; Clark, Robert A.

2002-05-01

MRI mammography has a number of advantages, including the tomographic, and therefore three-dimensional (3-D) nature, of the images. It allows the application of MRI mammography to breasts with dense tissue, post operative scarring, and silicon implants. However, due to the vast quantity of images and subtlety of difference in MR sequence, there is a need for reliable computer diagnosis to reduce the radiologist's workload. The purpose of this work was to develop automatic breast/tissue segmentation and visualization algorithms to aid physicians in detecting and observing abnormalities in breast. Two segmentation algorithms were developed: one for breast segmentation, the other for glandular tissue segmentation. In breast segmentation, the MRI image is first segmented using an adaptive growing clustering method. Two tracing algorithms were then developed to refine the breast air and chest wall boundaries of breast. The glandular tissue segmentation was performed using an adaptive thresholding method, in which the threshold value was spatially adaptive using a sliding window. The 3D visualization of the segmented 2D slices of MRI mammography was implemented under IDL environment. The breast and glandular tissue rendering, slicing and animation were displayed.

Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf

NASA Astrophysics Data System (ADS)

Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; An Nguyen, Thien; Alfano, Robert R.

2014-06-01

Two-photon (2P) excitation of the second singlet (S) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S2 state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf.

PubMed

Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; Nguyen, Thien An; Alfano, Robert R

2014-06-01

Two-photon (2P) excitation of the second singlet (S₂) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S₂ state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S₂ state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

Syringe-injectable mesh electronics integrate seamlessly with minimal chronic immune response in the brain

PubMed Central

Zhou, Tao; Hong, Guosong; Fu, Tian-Ming; Yang, Xiao; Schuhmann, Thomas G.; Viveros, Robert D.; Lieber, Charles M.

2017-01-01

Implantation of electrical probes into the brain has been central to both neuroscience research and biomedical applications, although conventional probes induce gliosis in surrounding tissue. We recently reported ultraflexible open mesh electronics implanted into rodent brains by syringe injection that exhibit promising chronic tissue response and recording stability. Here we report time-dependent histology studies of the mesh electronics/brain-tissue interface obtained from sections perpendicular and parallel to probe long axis, as well as studies of conventional flexible thin-film probes. Confocal fluorescence microscopy images of the perpendicular and parallel brain slices containing mesh electronics showed that the distribution of astrocytes, microglia, and neurons became uniform from 2–12 wk, whereas flexible thin-film probes yield a marked accumulation of astrocytes and microglia and decrease of neurons for the same period. Quantitative analyses of 4- and 12-wk data showed that the signals for neurons, axons, astrocytes, and microglia are nearly the same from the mesh electronics surface to the baseline far from the probes, in contrast to flexible polymer probes, which show decreases in neuron and increases in astrocyte and microglia signals. Notably, images of sagittal brain slices containing nearly the entire mesh electronics probe showed that the tissue interface was uniform and neurons and neurofilaments penetrated through the mesh by 3 mo postimplantation. The minimal immune response and seamless interface with brain tissue postimplantation achieved by ultraflexible open mesh electronics probes provide substantial advantages and could enable a wide range of opportunities for in vivo chronic recording and modulation of brain activity in the future. PMID:28533392

Syringe-injectable mesh electronics integrate seamlessly with minimal chronic immune response in the brain.

PubMed

Zhou, Tao; Hong, Guosong; Fu, Tian-Ming; Yang, Xiao; Schuhmann, Thomas G; Viveros, Robert D; Lieber, Charles M

2017-06-06

Implantation of electrical probes into the brain has been central to both neuroscience research and biomedical applications, although conventional probes induce gliosis in surrounding tissue. We recently reported ultraflexible open mesh electronics implanted into rodent brains by syringe injection that exhibit promising chronic tissue response and recording stability. Here we report time-dependent histology studies of the mesh electronics/brain-tissue interface obtained from sections perpendicular and parallel to probe long axis, as well as studies of conventional flexible thin-film probes. Confocal fluorescence microscopy images of the perpendicular and parallel brain slices containing mesh electronics showed that the distribution of astrocytes, microglia, and neurons became uniform from 2-12 wk, whereas flexible thin-film probes yield a marked accumulation of astrocytes and microglia and decrease of neurons for the same period. Quantitative analyses of 4- and 12-wk data showed that the signals for neurons, axons, astrocytes, and microglia are nearly the same from the mesh electronics surface to the baseline far from the probes, in contrast to flexible polymer probes, which show decreases in neuron and increases in astrocyte and microglia signals. Notably, images of sagittal brain slices containing nearly the entire mesh electronics probe showed that the tissue interface was uniform and neurons and neurofilaments penetrated through the mesh by 3 mo postimplantation. The minimal immune response and seamless interface with brain tissue postimplantation achieved by ultraflexible open mesh electronics probes provide substantial advantages and could enable a wide range of opportunities for in vivo chronic recording and modulation of brain activity in the future.

A rapid method for the assessment of bone architecture by confocal microscopy.

PubMed

Zheng, M H; Bruining, H G; Cody, S H; Brankov, B; Wood, D J; Papadimitriou, J M

1997-08-01

Conventional ways of demonstrating and analysing the components of osseous tissue have always been hampered by the difficulty of physically sectioning bone. In this study, we have used Acridine Orange staining of 100-micron-thick unembedded bone slices and then assessed the cellular and tissue architecture by confocal microscopy. The result showed the Acridine Orange, by differential staining of the cellular nucleic acids, permits ready assessment of cell shape and cell organization as well as variations in growth patterns. Our studies have provided a new and relatively easy way of assessing the morphology of bone specimens by rendering unnecessary the need for embedding, decalcification and thin sectioning of the osseous tissue.

Validation of a free software for unsupervised assessment of abdominal fat in MRI.

PubMed

Maddalo, Michele; Zorza, Ivan; Zubani, Stefano; Nocivelli, Giorgio; Calandra, Giulio; Soldini, Pierantonio; Mascaro, Lorella; Maroldi, Roberto

2017-05-01

To demonstrate the accuracy of an unsupervised (fully automated) software for fat segmentation in magnetic resonance imaging. The proposed software is a freeware solution developed in ImageJ that enables the quantification of metabolically different adipose tissues in large cohort studies. The lumbar part of the abdomen (19cm in craniocaudal direction, centered in L3) of eleven healthy volunteers (age range: 21-46years, BMI range: 21.7-31.6kg/m 2 ) was examined in a breath hold on expiration with a GE T1 Dixon sequence. Single-slice and volumetric data were considered for each subject. The results of the visceral and subcutaneous adipose tissue assessments obtained by the unsupervised software were compared to supervised segmentations of reference. The associated statistical analysis included Pearson correlations, Bland-Altman plots and volumetric differences (VD % ). Values calculated by the unsupervised software significantly correlated with corresponding supervised segmentations of reference for both subcutaneous adipose tissue - SAT (R=0.9996, p<0.001) and visceral adipose tissue - VAT (R=0.995, p<0.001). Bland-Altman plots showed the absence of systematic errors and a limited spread of the differences. In the single-slice analysis, VD % were (1.6±2.9)% for SAT and (4.9±6.9)% for VAT. In the volumetric analysis, VD % were (1.3±0.9)% for SAT and (2.9±2.7)% for VAT. The developed software is capable of segmenting the metabolically different adipose tissues with a high degree of accuracy. This free add-on software for ImageJ can easily have a widespread and enable large-scale population studies regarding the adipose tissue and its related diseases. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Custom-built tools for the study of deer antler biology.

PubMed

Chu, Wenhui; Zhao, Haiping; Li, Junde; Li, Chunyi

2017-06-01

Deer antlers can be developed into multiple novel models to study growth and development of tissues for biomedical research. To facilitate this process, we have invented and further refined five custom-built tools through three decades of antler research. These are: 1. Pedicle growth detector to pinpoint the timing when pedicle growth is initiated, thus stimuli for pedicle and first antler formation can be investigated and identified. 2. Thin periosteum slice cutter to thinly slice (0.2mm or 0.7 mm thick) a whole piece of antlerogenic periosteum (AP) or pedicle periosteum (PP), which facilitates gene delivery into cells resident in these tissues, thus making transgenic antlers possible. 3. The porous periosteum multi-needle punch to effectively loosen the dense AP or PP tissue. This allows most cells of the periosteum to come into direct contact with treating solutions, thus making artificial manipulation of antler development possible. 4. The intra-dermal pocket maker to cut the thin dermal tissue (less than 2 mm in thickness) of a male deer calf horizontally into two layers to make an intra-dermal pocket. This allows loading of AP tissue intra-dermally to test the theory of "antler stem cell niche" in vivo . 5. The sterile periosteum sampling system to allow aseptic collection of the AP, PP or the antler growth centre tissue on farm, thus allowing antler generation, regeneration or rapid growth to be investigated in vitro . Overall, we believe the application of contemporary cellular and molecular biological techniques coupled with these custom-built tools would greatly promote the establishment of this unique and novel model for the benefits of biomedical research, and hence human health.

High-sensitivity terahertz imaging of traumatic brain injury in a rat model

NASA Astrophysics Data System (ADS)

Zhao, Hengli; Wang, Yuye; Chen, Linyu; Shi, Jia; Ma, Kang; Tang, Longhuang; Xu, Degang; Yao, Jianquan; Feng, Hua; Chen, Tunan

2018-03-01

We demonstrated that different degrees of experimental traumatic brain injury (TBI) can be differentiated clearly in fresh slices of rat brain tissues using transmission-type terahertz (THz) imaging system. The high absorption region in THz images corresponded well with the injured area in visible images and magnetic resonance imaging results. The THz image and absorption characteristics of dehydrated paraffin-embedded brain slices and the hematoxylin and eosin (H&E)-stained microscopic images were investigated to account for the intrinsic differences in the THz images for the brain tissues suffered from different degrees of TBI and normal tissue aside from water. The THz absorption coefficients of rat brain tissues showed an increase in the aggravation of brain damage, particularly in the high-frequency range, whereas the cell density decreased as the order of mild, moderate, and severe TBI tissues compared with the normal tissue. Our results indicated that the different degrees of TBI were distinguishable owing to the different water contents and probable hematoma components distribution rather than intrinsic cell intensity. These promising results suggest that THz imaging has great potential as an alternative method for the fast diagnosis of TBI.

Investigating Functional Regeneration in Organotypic Spinal Cord Co-cultures Grown on Multi-electrode Arrays.

PubMed

Heidemann, Martina; Streit, Jürg; Tscherter, Anne

2015-09-23

Adult higher vertebrates have a limited potential to recover from spinal cord injury. Recently, evidence emerged that propriospinal connections are a promising target for intervention to improve functional regeneration. So far, no in vitro model exists that grants the possibility to examine functional recovery of propriospinal fibers. Therefore, a representative model that is based on two organotypic spinal cord sections of embryonic rat, cultured next to each other on multi-electrode arrays (MEAs) was developed. These slices grow and, within a few days in vitro, fuse along the sides facing each other. The design of the used MEAs permits the performance of lesions with a scalpel blade through this fusion site without inflicting damage on the MEAs. The slices show spontaneous activity, usually organized in network activity bursts, and spatial and temporal activity parameters such as the location of burst origins, speed and direction of their propagation and latencies between bursts can be characterized. Using these features, it is also possible to assess functional connection of the slices by calculating the amount of synchronized bursts between the two sides. Furthermore, the slices can be morphologically analyzed by performing immunohistochemical stainings after the recordings. Several advantages of the used techniques are combined in this model: the slices largely preserve the original tissue architecture with intact local synaptic circuitry, the tissue is easily and repeatedly accessible and neuronal activity can be detected simultaneously and non-invasively in a large number of spots at high temporal resolution. These features allow the investigation of functional regeneration of intraspinal connections in isolation in vitro in a sophisticated and efficient way.

Magnetic resonance imaging, computed tomography, and gross anatomy of the canine tarsus.

PubMed

Deruddere, Kirsten J; Milne, Marjorie E; Wilson, Kane M; Snelling, Sam R

2014-11-01

To describe the normal anatomy of the soft tissues of the canine tarsus as identified on computed tomography (CT) and magnetic resonance imaging (MRI) and to evaluate specific MRI sequences and planes for observing structures of diagnostic interest. Prospective descriptive study. Canine cadavers (n = 3). A frozen cadaver pelvic limb was used to trial multiple MRI sequences using a 1.5 T superconducting magnet and preferred sequences were selected. Radiographs of 6 canine cadaver pelvic limbs confirmed the tarsi were radiographically normal. A 16-slice CT scanner was used to obtain 1 mm contiguous slices through the tarsi. T1-weighted, proton density with fat suppression (PD FS) and T2-weighted MRI sequences were obtained in the sagittal plane, T1-weighted, and PD FS sequences in the dorsal plane and PD FS sequences in the transverse plane. The limbs were frozen for one month and sliced into 4-5 mm thick frozen sections. Anatomic sections were photographed and visually correlated to CT and MR images. Most soft tissue structures were easiest to identify on the transverse MRI sections with cross reference to either the sagittal or dorsal plane. Bony structures were easily identified on all CT, MR, and gross sections. The anatomy of the canine tarsus can be readily identified on MR imaging. © Copyright 2014 by The American College of Veterinary Surgeons.

In vitro studies on the putative function of N-acetylaspartate as an osmoregulator.

PubMed

Tranberg, Mattias; Abbas, Abdul-Karim; Sandberg, Mats

2007-07-01

Efflux and tissue content of N-acetylaspartate (NAA) and amino acids were evaluated from cultured and acutely prepared hippocampal slices in response to changes in osmolarity. The osmoregulator taurine, but not NAA, was lost from both types of slices after moderate reductions in extracellular osmolarity (-60 mOsm) for 10-48 h. Hypoosmotic shock (-166 mOsm) for 5 min resulted in unselective efflux of several amino acids from acutely prepared slices. Notably, the efflux of taurine, but not NAA, was prominent also after the shock. Efflux of NAA was markedly enhanced by NMDA and high K(+), in particular after the stimulation period. The high K(+)-mediated efflux was decreased by high extracellular osmolarity and a NMDA-receptor antagonist. The results indicate that NAA efflux can be induced by a sudden non-physiological decrease in extracellular osmolarity but not by prolonged more moderate changes in osmolarity. The mechanisms behind the efflux of NAA by high K(+) are complex and may involve both swelling and activation of NMDA-receptors.

Neuronal network imaging in acute slices using Ca2+ sensitive bioluminescent reporter.

PubMed

Tricoire, Ludovic; Lambolez, Bertrand

2014-01-01

Genetically encoded indicators are valuable tools to study intracellular signaling cascades in real time using fluorescent or bioluminescent imaging techniques. Imaging of Ca(2+) indicators is widely used to record transient intracellular Ca(2+) increases associated with bioelectrical activity. The natural bioluminescent Ca(2+) sensor aequorin has been historically the first Ca(2+) indicator used to address biological questions. Aequorin imaging offers several advantages over fluorescent reporters: it is virtually devoid of background signal; it does not require light excitation and interferes little with intracellular processes. Genetically encoded sensors such as aequorin are commonly used in dissociated cultured cells; however it becomes more challenging to express them in differentiated intact specimen such as brain tissue. Here we describe a method to express a GFP-aequorin (GA) fusion protein in pyramidal cells of neocortical acute slices using recombinant Sindbis virus. This technique allows expressing GA in several hundreds of neurons on the same slice and to perform the bioluminescence recording of Ca(2+) transients in single neurons or multiple neurons simultaneously.

Glycogen in the Nervous System. I; Methods for Light and Electron Microscopy

NASA Technical Reports Server (NTRS)

Estable, Rosita F. De; Estable-Puig, J. F.; Miquel, J.

1964-01-01

'l'he relative value of different methods for combined light and electron microscopical studies of glycogen in the nervous tissue was investigated. Picroalcoholic fixatives preserve glycogen in a considerable amount but give an inadequate morphological image of glycogen distribution and are unsuitable for ultrastructural studies. Fixation by perfusion, with Dalton's chromeosmic fluid seems adequate for ultrastructural cytochemistry of glycogen. Furthermore it permits routine paraffin embedding of brain slices adjacent to those used for electron microscopy. Dimedone blocking is a necessary step for a selective staining of glycogen with PAS after osmic fixation. Enzymatic removal of glycogen in osmic fixed nervous tissue can be done In paraffin-embedded tissue. It can also be performed in glycolmethacrylate-embedded tissue without removal of the embedding medium. Paraphenylenediamine stains glycogen following periodic acid oxidation.

A Novel Ex Vivo Method for Visualizing Live-Cell Calcium Response Behavior in Intact Human Tumors.

PubMed

Koh, James; Hogue, Joyce A; Sosa, Julie A

2016-01-01

The functional impact of intratumoral heterogeneity has been difficult to assess in the absence of a means to interrogate dynamic, live-cell biochemical events in the native tissue context of a human tumor. Conventional histological methods can reveal morphology and static biomarker expression patterns but do not provide a means to probe and evaluate tumor functional behavior and live-cell responsiveness to experimentally controlled stimuli. Here, we describe an approach that couples vibratome-mediated viable tissue sectioning with live-cell confocal microscopy imaging to visualize human parathyroid adenoma tumor cell responsiveness to extracellular calcium challenge. Tumor sections prepared as 300 micron-thick tissue slices retain viability throughout a >24 hour observation period and retain the native architecture of the parental tumor. Live-cell observation of biochemical signaling in response to extracellular calcium challenge in the intact tissue slices reveals discrete, heterogeneous kinetic waveform categories of calcium agonist reactivity within each tumor. Plotting the proportion of maximally responsive tumor cells as a function of calcium concentration yields a sigmoid dose-response curve with a calculated calcium EC50 value significantly elevated above published reference values for wild-type calcium-sensing receptor (CASR) sensitivity. Subsequent fixation and immunofluorescence analysis of the functionally evaluated tissue specimens allows alignment and mapping of the physical characteristics of individual cells within the tumor to specific calcium response behaviors. Evaluation of the relative abundance of intracellular PTH in tissue slices challenged with variable calcium concentrations demonstrates that production of the hormone can be dynamically manipulated ex vivo. The capability of visualizing live human tumor tissue behavior in response to experimentally controlled conditions opens a wide range of possibilities for personalized ex vivo therapeutic testing. This highly adaptable system provides a unique platform for live-cell ex vivo provocative testing of human tumor responsiveness to a range of physiological agonists or candidate therapeutic compounds.

Continuous pyruvate carbon flux to newly synthesized cholesterol and the suppressed evolution of pyruvate-generated CO2 in tumors: further evidence for a persistent truncated Krebs cycle in hepatomas.

PubMed

Parlo, R A; Coleman, P S

1986-04-29

Viable tissue slices from rat liver and Morris hepatoma 3924A were compared as to their ability to incorporate carbons from [U-14 C]pyruvate into newly synthesized cholesterol versus CO2. By 4 h, the tumor slice incubation had incorporated over 6-fold more pyruvate carbons into the sterol than into CO2, relative to the normal liver slice incubation, per g tissue protein. However, the presence of the mitochondrial citrate exchange carrier inhibitor 1,2,3-benzenetricarboxylate in the incubation inhibited the formation of [14C]cholesterol, while simultaneously leading to an increase in the rate of 14CO2 production in the tumor. In the normal liver system by contrast, benzenetricarboxylate also inhibited [14C]cholesterol formation, but had hardly any effect on the already high rate of 14CO2 production. The ability of benzenetricarboxylate to inhibit the rapid carbon flux from pyruvate to cholesterol, and to steer the metabolic flow of carbons toward oxidative decarboxylation via the Krebs cycle in whole, viable tumor tissue, indirectly emphasizes the importance of the mitochondrial citrate exchange carrier in supporting the decontrol of cholesterogenesis de novo in tumors by accelerating the supply of lipogenic precursor carbons to the tumor cytosol. These studies may be therefore interpreted as extensions, to the level of whole-cell metabolism, of the concept of a persistent 'truncated' Krebs cycle in the mitochondria of metastatic cancer tissue. This concept states, in part, that a rapid efflux of mitochondrially generated citrate would operate preferentially in tumors, and thus provide carbons continuously to the cytoplasmic compartment where the well-established deregulated pathway of cholesterogenesis occurs (Parlo, R.A. and Coleman, P.S. (1984) J. Biol. Chem. 259, 9997-10003; Coleman, P.S. and Lavietes, B.B. (1981) CRC Crit. Rev. Biochem. 11, 341-393).

Blood cell oxidative stress precedes hemolysis in whole blood-liver slice co-cultures of rat, dog, and human tissues

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

Vickers, Alison E.M., E-mail: vickers_alison@allergan.co; Sinclair, John R.; Fisher, Robyn L.

A novel in vitro model to investigate time-dependent and concentration-dependent responses in blood cells and hemolytic events is studied for rat, dog, and human tissues. Whole blood is co-cultured with a precision-cut liver slice. Methimazole (MMI) was selected as a reference compound, since metabolism of its imidazole thione moiety is linked with hematologic disorders and hepatotoxicity. An oxidative stress response occurred in all three species, marked by a decline in blood GSH levels by 24 h that progressed, and preceded hemolysis, which occurred at high MMI concentrations in the presence of a liver slice with rat (>= 1000 muM atmore » 48 h) and human tissues (>= 1000 muM at 48 h, >= 750 muM at 72 h) but not dog. Human blood-only cultures exhibited a decline of GSH levels but minimal to no hemolysis. The up-regulation of liver genes for heme degradation (Hmox1 and Prdx1), iron cellular transport (Slc40a1), and GSH synthesis and utilization (mGST1 and Gclc) were early markers of the oxidative stress response. The up-regulation of the Kupffer cell lectin Lgals3 gene expression indicated a response to damaged red blood cells, and Hp (haptoglobin) up-regulation is indicative of increased hemoglobin uptake. Up-regulation of liver IL-6 and IL-8 gene expression suggested an activation of an inflammatory response by liver endothelial cells. In summary, MMI exposure led to an oxidative stress response in blood cells, and an up-regulation of liver genes involved with oxidative stress and heme homeostasis, which was clearly separate and preceded frank hemolysis.« less

Effects of the calcium channel blocker verapamil and sulphydryl reducing agent dithiothreitol on atractyloside toxicity in precision-cut rat renal cortical and liver slices.

PubMed

Obatomi, D K; Blackburn, R O; Bach, P H

2001-10-01

The effects of dithiothreitol (DTT), a sulfhydryl-containing agent and verapamil (VRP), a calcium channel blocker as possible cytoprotectants against the atractyloside-induced toxicity were characterized in rat kidney and liver slices in vitro using multiple markers of toxicity. Precision-cut slices (200 microM thick) were either incubated with atractyloside (2 mM) or initially preincubated with either DTT (5 mM) or VRP (100 microM) for 30 min followed by exposure to atractyloside (2 mM) for 3 h at 37 degrees C on a rocker platform rotated at approximately 3 rpm. All of the toxicity parameters were sensitive to exposure to atractyloside, but treatment with DTT or VRP alone did not provide any indication of damage to the tissues. Preincubation of slices containing either DTT or VRP for 30 min provided total protection against atractyloside-induced increase in LDH leakage in both kidney and liver slices. Increased induction of lipid peroxidation by atractyloside in liver slices was completely abolished by DTT and VRP. Both DTT and VRP provided partial protection against atractyloside-induced inhibition of gluconeogenesis in both kidney and liver slices. Atractyloside-induced ATP depletion in both kidney and liver slices was partially abolished by VRP but not DTT. The significant depletion of GSH in the kidney slices by atractyloside was completely reversed by DTT only, while VRP alone reversed the same process in liver slices. Decreased MTT reductive capacity and significant increase in ALT leakage caused by atractyloside in liver slices was partially reversed. Complete protection was achieved with both DTT and VRP against atractyloside-induced inhibition of PAH uptake in kidney slices. These findings suggest that both DTT and VRP exert cytoprotective effects in atractyloside-induced biochemical perturbation, effects that differ in liver and kidney. The effect of these agents on atractyloside has provided us with a further understanding of the molecular mechanism of its action.

Utility of spatially-resolved atmospheric pressure surface sampling and ionization techniques as alternatives to mass spectrometric imaging (MSI) in drug metabolism.

PubMed

Blatherwick, Eleanor Q; Van Berkel, Gary J; Pickup, Kathryn; Johansson, Maria K; Beaudoin, Marie-Eve; Cole, Roderic O; Day, Jennifer M; Iverson, Suzanne; Wilson, Ian D; Scrivens, James H; Weston, Daniel J

2011-08-01

Tissue distribution studies of drug molecules play an essential role in the pharmaceutical industry and are commonly undertaken using quantitative whole body autoradiography (QWBA) methods. The growing need for complementary methods to address some scientific gaps around radiography methods has led to increased use of mass spectrometric imaging (MSI) technology over the last 5 to 10 years. More recently, the development of novel mass spectrometric techniques for ambient surface sampling has redefined what can be regarded as "fit-for-purpose" for MSI in a drug metabolism and disposition arena. Together with a review of these novel alternatives, this paper details the use of two liquid microjunction (LMJ)-based mass spectrometric surface sampling technologies. These approaches are used to provide qualitative determination of parent drug in rat liver tissue slices using liquid extraction surface analysis (LESA) and to assess the performance of a LMJ surface sampling probe (LMJ-SSP) interface for quantitative assessment of parent drug in brain, liver and muscle tissue slices. An assessment of the utility of these spatially-resolved sampling methods is given, showing interdependence between mass spectrometric and QWBA methods, in particular there emerges a reason to question typical MSI workflows for drug metabolism; suggesting the expedient use of profile or region analysis may be more appropriate, rather than generating time-intensive molecular images of the entire tissue section.

Elastase-Induced Parenchymal Disruption and Airway Hyper Responsiveness in Mouse Precision Cut Lung Slices: Toward an Ex vivo COPD Model.

PubMed

Van Dijk, Eline M; Culha, Sule; Menzen, Mark H; Bidan, Cécile M; Gosens, Reinoud

2016-01-01

Background: COPD is a progressive lung disease characterized by emphysema and enhanced bronchoconstriction. Current treatments focused on bronchodilation can delay disease progression to some extent, but recovery or normalization of loss of lung function is impossible. Therefore, novel therapeutic targets are needed. The importance of the parenchyma in airway narrowing is increasingly recognized. In COPD, the parenchyma and extracellular matrix are altered, possibly affecting airway mechanics and enhancing bronchoconstriction. Our aim was to set up a comprehensive ex vivo Precision Cut Lung Slice (PCLS) model with a pathophysiology resembling that of COPD and integrate multiple readouts in order to study the relationship between parenchyma, airway functionality, and lung repair processes. Methods: Lungs of C57Bl/6J mice were sliced and treated ex vivo with elastase (2.5 μg/ml) or H 2 O 2 (200 μM) for 16 h. Following treatment, parenchymal structure, airway narrowing, and gene expression levels of alveolar Type I and II cell repair were assessed. Results: Following elastase, but not H 2 O 2 treatment, slices showed a significant increase in mean linear intercept (Lmi), reflective of emphysema. Only elastase-treated slices showed disorganization of elastin and collagen fibers. In addition, elastase treatment lowered both alveolar Type I and II marker expression, whereas H 2 O 2 stimulation lowered alveolar Type I marker expression only. Furthermore, elastase-treated slices showed enhanced methacholine-induced airway narrowing as reflected by increased pEC50 (5.87 at basal vs. 6.50 after elastase treatment) and Emax values (47.96 vs. 67.30%), and impaired chloroquine-induced airway opening. The increase in pEC50 correlated with an increase in mean Lmi. Conclusion: Using this model, we show that structural disruption of elastin fibers leads to impaired alveolar repair, disruption of the parenchymal compartment, and altered airway biomechanics, enhancing airway contraction. This finding may have implications for COPD, as the amount of elastin fiber and parenchymal tissue disruption is associated with disease severity. Therefore, we suggest that PCLS can be used to model certain aspects of COPD pathophysiology and that the parenchymal tissue damage observed in COPD contributes to lung function decline by disrupting airway biomechanics. Targeting the parenchymal compartment may therefore be a promising therapeutic target in the treatment of COPD.

TU-H-207A-03: CT Hounsfield Unit Accuracy: Effect of Beam Hardening On Phantom and Clinical Whole-Body CT Images

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

Ai, H; Wendt, R

2016-06-15

Purpose: To assess the effect of beam hardening on measured CT HU values. Methods: An anthropomorphic knee phantom was scanned with the CT component of a GE Discovery 690 PET/CT scanner (120kVp, 300mAs, 40?0.625mm collimation, pitch=0.984, FOV=500mm, matrix=512?512) with four different scan setups, each of which induces different degrees of beam hardening by introducing additional attenuation media into the field of view. Homogeneous voxels representing “soft tissue” and “bone” were segmented by HU thresholding followed by a 3D morphological erosion operation which removes the non-homogenous voxels located on the interface of thresholded tissue mask. HU values of segmented “soft tissue”more » and “bone” were compared.Additionally, whole-body CT data with coverage from the skull apex to the end of toes were retrospectively retrieved from seven PET/CT exams to evaluate the effect of beam hardening in vivo. Homogeneous bone voxels were segmented with the same method previously described. Total In-Slice Attenuation (TISA) for each CT slice, defined as the summation of HU values over all voxels within a CT slice, was calculated for all slices of the seven whole-body CT datasets and evaluated against the mean HU values of homogeneous bone voxels within that slice. Results: HU values measured from the phantom showed that while “soft tissue” HU values were unaffected, added attenuation within the FOV caused noticeable decreases in the measured HU values of “bone” voxels. A linear relationship was observed between bone HU and TISA for slices of the torso and legs, but not of the skull. Conclusion: Beam hardening effect is not an issue of concern for voxels with HU in the soft tissue range, but should not be neglected for bone voxels. A linear relationship exists between bone HU and the associated TISA in non-skull CT slices, which can be exploited to develop a correction strategy.« less

Non-uniform muscle fat replacement along the proximodistal axis in Duchenne muscular dystrophy.

PubMed

Hooijmans, M T; Niks, E H; Burakiewicz, J; Anastasopoulos, C; van den Berg, S I; van Zwet, E; Webb, A G; Verschuuren, J J G M; Kan, H E

2017-05-01

The progressive replacement of muscle tissue by fat in Duchenne muscular dystrophy (DMD) has been studied using quantitative MRI between, but not within, individual muscles. We studied fat replacement along the proximodistal muscle axis using the Dixon technique on a 3T MR scanner in 22 DMD patients and 12 healthy controls. Mean fat fractions per muscle per slice for seven lower and upper leg muscles were compared between and within groups assuming a parabolic distribution. Average fat fraction for a small central slice stack and a large coverage slice stack were compared to the value when the stack was shifted one slice (15 mm) up or down. Higher fat fractions were observed in distal and proximal muscle segments compared to the muscle belly in all muscles of the DMD subjects (p <0.001). A shift of 15 mm resulted in a difference in mean fat fraction which was on average 1-2% ranging up to 12% (p <0.01). The muscle end regions are exposed to higher mechanical strain, which points towards mechanical disruption of the sarcolemma as one of the key factors in the pathophysiology. Overall, this non-uniformity in fat replacement needs to be taken into account to prevent sample bias when applying quantitative MRI as biomarker in clinical trials for DMD. Copyright © 2017 Elsevier B.V. All rights reserved.

Antagonistic effects of beta-phenylethylamine on quinpirole- and (-)-sulpiride-induced changes in evoked dopamine release from rat striatal slices.

PubMed

Yamada, S; Harano, M; Tanaka, M

1998-02-19

To assess the role of beta-phenylethylamine in aspects of dopamine release, we measured the level of beta-phenylethylamine in the rat striatum after killing the rats by microwave irradiation. We then investigated the effect of beta-phenylethylamine on electrically evoked dopamine release from rat striatal slices in vitro. The striatal beta-phenylethylamine level was 46.5 +/- 3.5 ng/g wet tissue, equivalent to 0.3 micromol/l. Superfusion with low concentrations of beta-phenylethylamine up to 1 micromol/l had no effect on spontaneous or electrically evoked dopamine release from striatal slices. Quinpirole reduced the evoked dopamine release from slices in a concentration-dependent manner. The quinpirole-induced reduction of evoked dopamine release was attenuated 30% by superfusion with 0.3 micromol/l beta-phenylethylamine. Moreover, the (-)-sulpiride (0.1 micromol/l)-induced increase in evoked dopamine release was also attenuated by superfusion with 0.3 micromol/l beta-phenylethylamine. These data indicate that submicromolar levels of beta-phenylethylamine could modify the dopamine autoreceptor mediated changes in evoked dopamine release from rat striatal slices.

Effect of halide salts on development of surface browning on fresh-cut 'Granny Smith' (Malus × domestica Borkh) apple slices during storage at low temperature.

PubMed

Li, Yongxin; Wills, Ron B H; Golding, John B; Huque, Roksana

2015-03-30

The postharvest life of fresh-cut apple slices is limited by browning on cut surfaces. Dipping in halide salt solutions was examined for their inhibition of surface browning on 'Granny Smith' apple slices and the effects on biochemical factors associated with browning. Delay in browning by salts was greatest with chloride = phosphate > sulfate > nitrate with no difference between sodium, potassium and calcium ions. The effectiveness of sodium halides on browning was fluoride > chloride = bromide > iodide = control. Polyphenol oxidase (PPO) activity of tissue extracted from chloride- and fluoride-treated slices was not different to control but when added into the assay solution, NaF > NaCl both showed lower PPO activity at pH 3-5 compared to control buffer. The level of polyphenols in treated slices was NaF > NaCl > control. Addition of chlorogenic acid to slices enhanced browning but NaCl and NaF counteracted this effect. There was no effect of either halide salt on respiration, ethylene production, ion leakage, and antioxidant activity. Dipping apple slices in NaCl is a low cost treatment with few impediments to commercial use and could be a replacement for other anti-browning additives. The mode of action of NaCl and NaF is through decreasing PPO activity resulting in reduced oxidation of polyphenols. © 2014 Society of Chemical Industry.

DiOlistic Labeling of Neurons in Tissue Slices: A Qualitative and Quantitative Analysis of Methodological Variations.

PubMed

Staffend, Nancy A; Meisel, Robert L

2011-01-01

Fine neuronal morphology, such as dendritic spines, classically has been studied using the Golgi technique; however, Golgi staining is difficult to combine with other histological techniques. With the increasing popularity of fluorescent imaging, a number of fluorescent dyes have been developed that enable the coupling of multiple fluorescent labels in a single preparation. These fluorescent dyes include the lipophilic dialkylcarbocyanine, DiI; traditionally used for anterograde and retrograde neuronal tracing. More recently, DiI labeling has been used in combination with the Gene Gun for "DiOlistic" labeling of neurons in slice preparations. DiI sequesters itself within and diffuses laterally along the neuronal membrane, however once the cell is permeabilized, the DiI begins to leak from the cell membrane. A DiI derivative, Cell Tracker™ CM-DiI, increases dye stability and labeling half-life in permeabilized tissue, however at much greater expense. Here, the DiI and CM-DiI DiOlistic labeling techniques were tested in side-by-side experiments evaluating dye stability within dendritic architecture in medium spiny neurons of the dorsal stratum in both non-permeabilized and permeabilized tissue sections. In tissue sections that were not permeabilized, spine density in DiI labeled sections was higher than in CM-DiI labeling. In contrast, tissue sections that were permeabilized had higher spine densities in CM-DiI labeled neurons. These results suggest that for experiments involving non-permeabilized tissue, traditional DiI will suffice, however for experiments involving permeabilized tissue CM-DiI provides more consistent data. These experiments provide the first quantitative analyses of the impact of methodological permutations on neuronal labeling with DiI.

Acute Slices of Mice Testis Seminiferous Tubules Unveil Spontaneous and Synchronous Ca2+ Oscillations in Germ Cell Clusters1

PubMed Central

Sánchez-Cárdenas, Claudia; Guerrero, Adán; Treviño, Claudia Lydia; Hernández-Cruz, Arturo; Darszon, Alberto

2012-01-01

ABSTRACT Spermatogenic cell differentiation involves changes in the concentration of cytoplasmic Ca2+ ([Ca2+]i); however, very few studies exist on [Ca2+]i dynamics in these cells. Other tissues display Ca2+ oscillations involving multicellular functional arrangements. These phenomena have been studied in acute slice preparations that preserve tissue architecture and intercellular communications. Here we report the implementation of intracellular Ca2+ imaging in a sliced seminiferous tubule (SST) preparation to visualize [Ca2+]i changes of living germ cells in situ within the SST preparation. Ca2+ imaging revealed that a subpopulation of male germ cells display spontaneous [Ca2+]i fluctuations resulting from Ca2+ entry possibly throughout CaV3 channels. These [Ca2+]i fluctuation patterns are also present in single acutely dissociated germ cells, but they differ from those recorded from germ cells in the SST preparation. Often, spontaneous Ca2+ fluctuations of spermatogenic cells in the SST occur synchronously, so that clusters of cells can display Ca2+ oscillations for at least 10 min. Synchronous Ca2+ oscillations could be mediated by intercellular communication via gap junctions, although intercellular bridges could also be involved. We also observed an increase in [Ca2+]i after testosterone application, suggesting the presence of functional Sertoli cells in the SST. In summary, we believe that the SST preparation is suitable to explore the physiology of spermatogenic cells in their natural environment, within the seminiferous tubules, in particular Ca2+ signaling phenomena, functional cell-cell communication, and multicellular functional arrangements. PMID:22914313

Soft-tissue tumor differentiation using 3D power Doppler ultrasonography with echo-contrast medium injection.

PubMed

Chiou, Hong-Jen; Chou, Yi-Hong; Chen, Wei-Ming; Chen, Winby; Wang, Hsin-Kai; Chang, Cheng-Yen

2010-12-01

We aimed to evaluate the ability of 3-dimensional power Doppler ultrasonography to differentiate soft-tissue masses from blood flow and vascularization with contrast medium. Twenty-five patients (mean age, 44.1 years; range, 12-77 years) with a palpable mass were enrolled in this study. Volume data were acquired using linear and convex 3-dimensional probes and contrast medium injected manually by bolus. Data were stored and traced slice by slice for 12 slices. All patients were scanned by the same senior sonologist. The vascular index (VI), flow index (FI), and vascular-flow index (VFI) were automatically calculated after the tumor was completely traced. All tumors were later confirmed by pathology. The study included 8 benign (mean, 36.5 mL; range, 2.4-124 mL) and 17 malignant (mean, 319.4 mL; range, 9.9-1,179.6 mL) tumors. Before contrast medium injection, mean VI, FI and VFI were, respectively, 3.22, 32.26 and 1.07 in benign tumors, and 1.97, 29.33 and 0.67 in malignant tumors. After contrast medium injection, they were, respectively, 20.85, 37.33 and 8.52 in benign tumors, and 40.12, 41.21 and 17.77 in malignant tumors. The mean differences between with and without contrast injection for VI, FI and VFI were, respectively, 17.63, 5.07 and 7.45 in benign tumors, and 38.15, 11.88 and 16.55 in malignant tumors. Tumor volume, VI, FI and VFI were not significantly different between benign and malignant tumors before and after echo-contrast medium injection. However, VI, FI and VFI under self-differentiation (differences between with and without contrast injection) were significantly different between malignant and benign tumors. Three-dimensional power Doppler ultrasound is a valuable tool for differential diagnosis of soft-tissue tumors, especially with the injection of an echo-contrast medium. Copyright © 2010 Elsevier. Published by Elsevier B.V. All rights reserved.

Transformation diffusion reconstruction of three-dimensional histology volumes from two-dimensional image stacks.

PubMed

Casero, Ramón; Siedlecka, Urszula; Jones, Elizabeth S; Gruscheski, Lena; Gibb, Matthew; Schneider, Jürgen E; Kohl, Peter; Grau, Vicente

2017-05-01

Traditional histology is the gold standard for tissue studies, but it is intrinsically reliant on two-dimensional (2D) images. Study of volumetric tissue samples such as whole hearts produces a stack of misaligned and distorted 2D images that need to be reconstructed to recover a congruent volume with the original sample's shape. In this paper, we develop a mathematical framework called Transformation Diffusion (TD) for stack alignment refinement as a solution to the heat diffusion equation. This general framework does not require contour segmentation, is independent of the registration method used, and is trivially parallelizable. After the first stack sweep, we also replace registration operations by operations in the space of transformations, several orders of magnitude faster and less memory-consuming. Implementing TD with operations in the space of transformations produces our Transformation Diffusion Reconstruction (TDR) algorithm, applicable to general transformations that are closed under inversion and composition. In particular, we provide formulas for translation and affine transformations. We also propose an Approximated TDR (ATDR) algorithm that extends the same principles to tensor-product B-spline transformations. Using TDR and ATDR, we reconstruct a full mouse heart at pixel size 0.92µm×0.92µm, cut 10µm thick, spaced 20µm (84G). Our algorithms employ only local information from transformations between neighboring slices, but the TD framework allows theoretical analysis of the refinement as applying a global Gaussian low-pass filter to the unknown stack misalignments. We also show that reconstruction without an external reference produces large shape artifacts in a cardiac specimen while still optimizing slice-to-slice alignment. To overcome this problem, we use a pre-cutting blockface imaging process previously developed by our group that takes advantage of Brewster's angle and a polarizer to capture the outline of only the topmost layer of wax in the block containing embedded tissue for histological sectioning. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Photon Entanglement Through Brain Tissue.

PubMed

Shi, Lingyan; Galvez, Enrique J; Alfano, Robert R

2016-12-20

Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue. By spatially filtering the ballistic scattering of an entangled photon, we find that its polarization entanglement is preserved and non-locally correlated with its twin in the TS plots. The degree of entanglement correlates better with structure and water content than with sample thickness.

Photon Entanglement Through Brain Tissue

NASA Astrophysics Data System (ADS)

Shi, Lingyan; Galvez, Enrique J.; Alfano, Robert R.

2016-12-01

Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue. By spatially filtering the ballistic scattering of an entangled photon, we find that its polarization entanglement is preserved and non-locally correlated with its twin in the TS plots. The degree of entanglement correlates better with structure and water content than with sample thickness.

Anatomical Distribution of Lipids in Human Brain Cortex by Imaging Mass Spectrometry

NASA Astrophysics Data System (ADS)

Veloso, Antonio; Astigarraga, Egoitz; Barreda-Gómez, Gabriel; Manuel, Iván; Ferrer, Isidro; Teresa Giralt, María; Ochoa, Begoña; Fresnedo, Olatz; Rodríguez-Puertas, Rafael; Fernández, José A.

2011-02-01

Molecular mass images of tissues will be biased if differences in the physicochemical properties of the microenvironment affect the intensity of the spectra. To address this issue, we have performed—by means of MALDI-TOF mass spectrometry—imaging on slices and lipidomic analysis in extracts of frontal cortex, both from the same postmortem tissue samples of human brain. An external calibration was used to achieve a mass accuracy of 10 ppm (1 σ) in the spectra of the extracts, although the final assignment was based on a comparison with previously reported species. The spectra recorded directly from tissue slices (imaging) show excellent s/n ratios, almost comparable to those obtained from the extracts. In addition, they retain the information about the anatomical distribution of the molecular species present in autopsied frozen tissue. Further comparison between the spectra from lipid extracts devoid of proteins and those recorded directly from the tissue unambiguously show that the differences in lipid composition between gray and white matter observed in the mass images are not an artifact due to microenvironmental influences of each anatomical area on the signal intensity, but real variations in the lipid composition.

The value of "liver windows" settings in the detection of small renal cell carcinomas on unenhanced computed tomography.

PubMed

Sahi, Kamal; Jackson, Stuart; Wiebe, Edward; Armstrong, Gavin; Winters, Sean; Moore, Ronald; Low, Gavin

2014-02-01

To assess if "liver window" settings improve the conspicuity of small renal cell carcinomas (RCC). Patients were analysed from our institution's pathology-confirmed RCC database that included the following: (1) stage T1a RCCs, (2) an unenhanced computed tomography (CT) abdomen performed ≤ 6 months before histologic diagnosis, and (3) age ≥ 17 years. Patients with multiple tumours, prior nephrectomy, von Hippel-Lindau disease, and polycystic kidney disease were excluded. The unenhanced CT was analysed, and the tumour locations were confirmed by using corresponding contrast-enhanced CT or magnetic resonance imaging studies. Representative single-slice axial, coronal, and sagittal unenhanced CT images were acquired in "soft tissue windows" (width, 400 Hounsfield unit (HU); level, 40 HU) and liver windows (width, 150 HU; level, 88 HU). In addition, single-slice axial, coronal, and sagittal unenhanced CT images of nontumourous renal tissue (obtained from the same cases) were acquired in soft tissue windows and liver windows. These data sets were randomized, unpaired, and were presented independently to 3 blinded radiologists for analysis. The presence or absence of suspicious findings for tumour was scored on a 5-point confidence scale. Eighty-three of 415 patients met the study criteria. Receiver operating characteristics (ROC) analysis, t test analysis, and kappa analysis were used. ROC analysis showed statistically superior diagnostic performance for liver windows compared with soft tissue windows (area under the curve of 0.923 vs 0.879; P = .0002). Kappa statistics showed "good" vs "moderate" agreement between readers for liver windows compared with soft tissue windows. Use of liver windows settings improves the detection of small RCCs on the unenhanced CT. Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Direct Visualization of Surfaces from Computed Tomography Data,

DTIC Science & Technology

1988-01-01

dominant method - slice-by-slice - makes comprehension of convoluted, small, or faint structures difficult. From a densitometric point of view, the human ...Di t SPeclal 4 N(xI) = Vf(lx) IVf (XI)I* There are many ways to estimate the gradient vector Vf(xi). The selection of an operator depends on the...the data is relatively noise-free or has been pre-smoothed. A graph of a(xi) as a function of f(xi) and IVf (xl)l for three tissue types A, B, and C

Ice formation in isolated human hepatocytes and human liver tissue.

PubMed

Bischof, J C; Ryan, C M; Tompkins, R G; Yarmush, M L; Toner, M

1997-01-01

Cryopreservation of isolated cells and tissue slices of human liver is required to furnish extracorporeal bioartificial liver devices with a ready supply of hepatocytes, and to create in vitro drug metabolism and toxicity models. Although both the bioartificial liver and many current biotoxicity models are based on reconstructing organ functions from single isolated hepatocytes, tissue slices offer an in vitro system that may more closely resemble the in vivo situation of the cells because of cell-cell and cell-extracellular matrix interactions. However, successful cryopreservation of both cellular and tissue level systems requires an increased understanding of the fundamental mechanisms involved in the response of the liver and its cells to freezing stress. This study investigates the biophysical mechanisms of water transport and intracellular ice formation during freezing in both isolated human hepatocytes and whole liver tissue. The effects of cooling rate on individual cells were measured using a cryomicroscope. Biophysical parameters governing water transport (Lpg = 2.8 microns/min-atm and ELp = 79 kcal/mole) and intracellular heterogeneous ice nucleation (omega het = 1.08 x 10(9) m-2s-1 and kappa het = 1.04 x 10(9) K5) were determined. These parameters were then incorporated into a theoretical Krogh cylinder model developed to simulate water transport and ice formation in intact liver tissue. Model simulations indicated that the cellular compartment of the Krogh model maintained more water than isolated cells under the same freezing conditions. As a result, intracellular ice nucleation occurred at lower cooling rates in the Krogh model than in isolated cells. Furthermore, very rapid cooling rates (1000 degrees C/min) showed a depression of heterogeneous nucleation and a shift toward homogeneous nucleation. The results of this study are in qualitative agreement with the findings of a previous experimental study of the response to freezing of intact human liver.

Study on tissue culture for Gelidium seedling

NASA Astrophysics Data System (ADS)

Pei, Lu-Qing; Luo, Qi-Jun; Fei, Zhi-Qing; Ma, Bin

1996-06-01

As seedling culture is a crucial factor for successful cultivation of Gelidium, the authors researched tissue culture technology for producing seedlings. The morphogeny and experimental ecology were observed and studied fully in 2 5 mm isolated tissue fragments. Regeneration, appearance of branching creepers and attaching structure and new erect seedlings production and development were studied. Fragments were sown on bamboo slice and vinylon rope. The seedlings were cultured 20 30 days indoor, then cultured in the sea, where the density of erect seedlings was 3 19 seedlings/cm2, growth rate was 3.84% day. The frond arising from seedlings directly was up to 10 cm per year. The ecological conditions for regenerated seedlings are similar to the natural ones. The regenerated seedlings are suitable for raft culture in various sea areas.

Apixaban decreases brain thrombin activity in a male mouse model of acute ischemic stroke.

PubMed

Bushi, Doron; Chapman, Joab; Wohl, Anton; Stein, Efrat Shavit; Feingold, Ekaterina; Tanne, David

2018-05-14

Factor Xa (FXa) plays a critical role in the coagulation cascade by generation of thrombin. During focal ischemia thrombin levels increase in the brain tissue and cause neural damage. This study examined the hypothesis that administration of the FXa inhibitor, apixaban, following focal ischemic stroke may have therapeutic potential by decreasing brain thrombin activity and infarct volume. Male mice were divided into a treated groups that received different doses of apixaban (2, 20, 100 mg/kg administered I.P.) or saline (controls) immediately after blocking the middle cerebral artery (MCA). Thrombin activity was measured by a fluorescence assay on fresh coronal slices taken from the mice brains 24 hr following the MCA occlusion. Infarct volume was assessed using triphenyltetrazolium chloride staining. A high dose of apixaban (100 mg/kg) significantly decreased thrombin activity levels in the ipsilateral hemisphere compared to the control group (Slice#5, p = .016; Slice#6, p = .016; Slice#7, p = .016; Slice#8, p = .036; by the nonparametric Mann-Whitney test). In addition, treatment with apixaban doses of both 100 mg/kg (32 ± 8% vs. 76 ± 7% in the treatment vs. control groups respectively; p = .005 by the nonparametric Mann-Whitney test) and 20 mg/kg (43 ± 7% vs. 76 ± 7% in the treatment vs. control groups respectively; p = .019 by the nonparametric Mann-Whitney test) decreased infarct volumes in areas surrounding the ischemic core (Slices #3 and #8). No brain hemorrhages were observed either in the treated or control groups. In summary, I.P. administration of high dose of apixaban immediately after MCA occlusion decreases brain thrombin activity and reduces infarct size. © 2018 Wiley Periodicals, Inc.

Preparing Fresh Retinal Slices from Adult Zebrafish for Ex Vivo Imaging Experiments.

PubMed

Giarmarco, Michelle M; Cleghorn, Whitney M; Hurley, James B; Brockerhoff, Susan E

2018-05-09

The retina is a complex tissue that initiates and integrates the first steps of vision. Dysfunction of retinal cells is a hallmark of many blinding diseases, and future therapies hinge on fundamental understandings about how different retinal cells function normally. Gaining such information with biochemical methods has proven difficult because contributions of particular cell types are diminished in the retinal cell milieu. Live retinal imaging can provide a view of numerous biological processes on a subcellular level, thanks to a growing number of genetically encoded fluorescent biosensors. However, this technique has thus far been limited to tadpoles and zebrafish larvae, the outermost retinal layers of isolated retinas, or lower resolution imaging of retinas in live animals. Here we present a method for generating live ex vivo retinal slices from adult zebrafish for live imaging via confocal microscopy. This preparation yields transverse slices with all retinal layers and most cell types visible for performing confocal imaging experiments using perfusion. Transgenic zebrafish expressing fluorescent proteins or biosensors in specific retinal cell types or organelles are used to extract single-cell information from an intact retina. Additionally, retinal slices can be loaded with fluorescent indicator dyes, adding to the method's versatility. This protocol was developed for imaging Ca 2+ within zebrafish cone photoreceptors, but with proper markers it could be adapted to measure Ca 2+ or metabolites in Müller cells, bipolar and horizontal cells, microglia, amacrine cells, or retinal ganglion cells. The retinal pigment epithelium is removed from slices so this method is not suitable for studying that cell type. With practice, it is possible to generate serial slices from one animal for multiple experiments. This adaptable technique provides a powerful tool for answering many questions about retinal cell biology, Ca 2+ , and energy homeostasis.

Application of Real-Time Fluorescent PCR for Quantitative Assessment of Neospora caninum Infections in Organotypic Slice Cultures of Rat Central Nervous System Tissue

PubMed Central

Müller, Norbert; Vonlaufen, Nathalie; Gianinazzi, Christian; Leib, Stephen L.; Hemphill, Andrew

2002-01-01

The previously described Nc5-specific PCR test for the diagnosis of Neospora caninum infections was used to develop a quantitative PCR assay which allows the determination of infection intensities within different experimental and diagnostic sample groups. The quantitative PCR was performed by using a dual fluorescent hybridization probe system and the LightCycler Instrument for online detection of amplified DNA. This assay was successfully applied for demonstrating the parasite proliferation kinetics in organotypic slice cultures of rat brain which were infected in vitro with N. caninum tachyzoites. This PCR-based method of parasite quantitation with organotypic brain tissue samples can be regarded as a novel ex vivo approach for exploring different aspects of cerebral N. caninum infection. PMID:11773124

Trans-proximal tubular steady-state concentration differences studied by micro-puncture and tissue content of sodium and chloride at varying intraluminal sodium concentrations in vitro in rat kidney cortex slices: evidence for a multisite sodium transport system.

PubMed Central

Györy, A Z; Roby, H

1977-01-01

1. With the aid of micropuncture techniques, proximal tubular transepithelial concentration differences for Na (deltaC Na) and chloride (deltaC Cl) were measured in kidney cortex slices at bathing fluid Na concentrations from 10 to 400 m-mole. kg-1. Tissue content of water, Na and K was also measured in such slices. Under steady-state conditions of zero net flux of NaCl and water, deltaC Na represents the sum of active Na transport, factored by the tubular permeability coefficient added to a component of flux due to electrical forces. 2. The relation between bathing fluid Na concentraton and deltaC Na appeared sigmoid in form suggesting an allosteric mechanism for the transport step. 3. Transtubular potential difference, calculated from transepithelial Cl distribution ratios, did not appear constant at the various bathing fluid Na concentrations. Correcting for the effect of these potential differences on the value of each deltaC Na did not convert the sigmoid transport curve to a hyperbolic one, confirming the suggested allosteric nature of the active Na transport step. 4. Intracellular Na content varied linearly with bathing fluid Na concentrations implying free entry of this cation into the cell. This also suggests that the sigmoid transport curve is related to the properties of the active Na transport pump. PMID:856986

Preclinical Characterization of 18F-MK-6240, a Promising PET Tracer for In Vivo Quantification of Human Neurofibrillary Tangles.

PubMed

Hostetler, Eric D; Walji, Abbas M; Zeng, Zhizhen; Miller, Patricia; Bennacef, Idriss; Salinas, Cristian; Connolly, Brett; Gantert, Liza; Haley, Hyking; Holahan, Marie; Purcell, Mona; Riffel, Kerry; Lohith, Talakad G; Coleman, Paul; Soriano, Aileen; Ogawa, Aimie; Xu, Serena; Zhang, Xiaoping; Joshi, Elizabeth; Della Rocca, Joseph; Hesk, David; Schenk, David J; Evelhoch, Jeffrey L

2016-10-01

A PET tracer is desired to help guide the discovery and development of disease-modifying therapeutics for neurodegenerative diseases characterized by neurofibrillary tangles (NFTs), the predominant tau pathology in Alzheimer disease (AD). We describe the preclinical characterization of the NFT PET tracer 18 F-MK-6240. In vitro binding studies were conducted with 3 H-MK-6240 in tissue slices and homogenates from cognitively normal and AD human brain donors to evaluate tracer affinity and selectivity for NFTs. Immunohistochemistry for phosphorylated tau was performed on human brain slices for comparison with 3 H-MK-6240 binding patterns on adjacent brain slices. PET studies were performed with 18 F-MK-6240 in monkeys to evaluate tracer kinetics and distribution in the brain. 18 F-MK-6240 monkey PET studies were conducted after dosing with unlabeled MK-6240 to evaluate tracer binding selectivity in vivo. The 3 H-MK-6240 binding pattern was consistent with the distribution of phosphorylated tau in human AD brain slices. 3 H-MK-6240 bound with high affinity to human AD brain cortex homogenates containing abundant NFTs but bound poorly to amyloid plaque-rich, NFT-poor AD brain homogenates. 3 H-MK-6240 showed no displaceable binding in the subcortical regions of human AD brain slices and in the hippocampus/entorhinal cortex of non-AD human brain homogenates. In monkey PET studies, 18 F-MK-6240 displayed rapid and homogeneous distribution in the brain. The 18 F-MK-6240 volume of distribution stabilized rapidly, indicating favorable tracer kinetics. No displaceable binding was observed in self-block studies in rhesus monkeys, which do not natively express NFTs. Moderate defluorination was observed as skull uptake. 18 F-MK-6240 is a promising PET tracer for the in vivo quantification of NFTs in AD patients. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Survival, migration, and differentiation of Sox1-GFP embryonic stem cells in coculture with an auditory brainstem slice preparation.

PubMed

Glavaski-Joksimovic, Aleksandra; Thonabulsombat, Charoensri; Wendt, Malin; Eriksson, Mikael; Palmgren, Björn; Jonsson, Anna; Olivius, Petri

2008-03-01

The poor regeneration capability of the mammalian hearing organ has initiated different approaches to enhance its functionality after injury. To evaluate a potential neuronal repair paradigm in the inner ear and cochlear nerve we have previously used embryonic neuronal tissue and stem cells for implantation in vivo and in vitro. At present, we have used in vitro techniques to study the survival and differentiation of Sox1-green fluorescent protein (GFP) mouse embryonic stem (ES) cells as a monoculture or as a coculture with rat auditory brainstem slices. For the coculture, 300 microm-thick brainstem slices encompassing the cochlear nucleus and cochlear nerve were prepared from postnatal SD rats. The slices were propagated using the membrane interface method and the cochlear nuclei were prelabeled with DiI. After some days in culture a suspension of Sox1 cells was deposited next to the brainstem slice. Following deposition Sox1 cells migrated toward the brainstem and onto the cochlear nucleus. GFP was not detectable in undifferentiated ES cells but became evident during neural differentiation. Up to 2 weeks after transplantation the cocultures were fixed. The undifferentiated cells were evaluated with antibodies against progenitor cells whereas the differentiated cells were determined with neuronal and glial markers. The morphological and immunohistochemical data indicated that Sox1 cells in monoculture differentiated into a higher percentage of glial cells than neurons. However, when a coculture was used a significantly lower percentage of Sox1 cells differentiated into glial cells. The results demonstrate that a coculture of Sox1 cells and auditory brainstem present a useful model to study stem cell differentiation.

Water Potential in Excised Leaf Tissue

PubMed Central

Nelsen, Charles E.; Safir, Gene R.; Hanson, Andrew D.

1978-01-01

Leaf water potential (Ψleaf) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Ψleaf values from the dew point hygrometer were too high. Agreement was improved by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Ψleaf values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status. PMID:16660227

Fiber optic biofluorometer for physiological research on muscle slices

NASA Astrophysics Data System (ADS)

Belz, Mathias; Dendorfer, Andreas; Werner, Jan; Lambertz, Daniel; Klein, Karl-Friedrich

2016-03-01

A focus of research in cell physiology is the detection of Ca2+, NADH, FAD, ATPase activity or membrane potential, only to name a few, in muscle tissues. In this work, we report on a biofluorometer using ultraviolet light emitting diodes (UV-LEDs), optical fibers and two photomultipliers (PMTs) using synchronized fluorescence detection with integrated background correction to detect free calcium, Ca2+, in cardiac muscle tissue placed in a horizontal tissue bath and a microscope setup. Fiber optic probes with imaging optics have been designed to transport excitation light from the biofluorometer's light output to a horizontal tissue bath and to collect emission light from a tissue sample of interest to two PMTs allowing either single excitation / single emission or ratiometric, dual excitation / single emission or single excitation / dual emission fluorescence detection of indicator dyes or natural fluorophores. The efficient transport of light from the excitation LEDs to the tissue sample, bleaching effects of the excitation light in both, polymer and fused silica-based fibers will be discussed. Furthermore, a new approach to maximize light collection of the emission light using high NA fibers and high NA coupling optics will be shown. Finally, first results on Ca2+ measurements in cardiac muscle slices in a traditional microscope setup and a horizontal tissue bath using fiber optic probes will be introduced and discussed.

Optical coefficient measurements using bulk living tissue by an optical fiber puncture with FOV change

NASA Astrophysics Data System (ADS)

Nakazawa, Haruna; Doi, Marika; Ogawa, Emiyu; Arai, Tsunenori

2018-02-01

To avoid an instability of the optical coefficient measurement using sliced tissue preparation, we proposed the combination of light intensity measurement through an optical fiber puncturing into a bulk tissue varying field of view (FOV) and ray tracing calculation using Monte-Carlo method. The optical coefficients of myocardium such as absorption coefficient μa, scattering coefficient μs, and anisotropic parameter g are used in the myocardium optical propagation. Since optical coefficients obtained using thin sliced tissue could be instable because they are affected by dehydration and intracellular fluid effusion on the sample surface, variety of coefficients have been reported over individual optical differences of living samples. The proposed method which combined the experiment using the bulk tissue with ray tracing calculation were performed. In this method, a 200 μmΦ high-NA silica fiber installed in a 21G needle was punctured up to the bottom of the myocardial bulk tissue over 3 cm in thickness to measure light intensity changing the fiber-tip depth and FOV. We found that the measured attenuation coefficients decreased as the FOV increased. The ray trace calculation represented the same FOV dependence in above mentioned experimental result. We think our particular fiber punctured measurement using bulk tissue varying FOV with Inverse Monte-Carlo method might be useful to obtain the optical coefficients to avoid sample preparation instabilities.

Silicon chip with capacitors and transistors for interfacing organotypic brain slice of rat hippocampus.

PubMed

Hutzler, Michael; Fromherz, Peter

2004-04-01

Probing projections between brain areas and their modulation by synaptic potentiation requires dense arrays of contacts for noninvasive electrical stimulation and recording. Semiconductor technology is able to provide planar arrays with high spatial resolution to be used with planar neuronal structures such as organotypic brain slices. To address basic methodical issues we developed a silicon chip with simple arrays of insulated capacitors and field-effect transistors for stimulation of neuronal activity and recording of evoked field potentials. Brain slices from rat hippocampus were cultured on that substrate. We achieved local stimulation of the CA3 region by applying defined voltage pulses to the chip capacitors. Recording of resulting local field potentials in the CA1 region was accomplished with transistors. The relationship between stimulation and recording was rationalized by a sheet conductor model. By combining a row of capacitors with a row of transistors we determined a simple stimulus-response matrix from CA3 to CA1. Possible contributions of inhomogeneities of synaptic projection, of tissue structure and of neuroelectronic interfacing were considered. The study provides the basis for a development of semiconductor chips with high spatial resolution that are required for long-term studies of topographic mapping.

Interpolation of 3D slice volume data for 3D printing

NASA Astrophysics Data System (ADS)

Littley, Samuel; Voiculescu, Irina

2017-03-01

Medical imaging from CT and MRI scans has become essential to clinicians for diagnosis, treatment planning and even prevention of a wide array of conditions. The presentation of image data volumes as 2D slice series provides some challenges with visualising internal structures. 3D reconstructions of organs and other tissue samples from data with low scan resolution leads to a `stepped' appearance. This paper demonstrates how to improve 3D visualisation of features and automated preparation for 3D printing from such low resolution data, using novel techniques for morphing from one slice to the next. The boundary of the starting contour is grown until it matches the boundary of the ending contour by adapting a variant of the Fast Marching Method (FMM). Our spoke based approach generates scalar speed field for FMM by estimating distances to boundaries with line segments connecting the two boundaries. These can be regularly spaced radial spokes or spokes at radial extrema. We introduce clamped FMM by running the algorithm outwards from the smaller boundary and inwards from the larger boundary and combining the two runs to achieve FMM growth stability near the two region boundaries. Our method inserts a series of uniformly distributed intermediate contours between each pair of consecutive slices from the scan volume thus creating smoother feature boundaries. Whilst hard to quantify, our overall results give clinicians an evidently improved tangible and tactile representation of the tissues, that they can examine more easily and even handle.

Kynurenine 3-mono-oxygenase inhibitors attenuate post-ischemic neuronal death in organotypic hippocampal slice cultures.

PubMed

Carpenedo, Raffaella; Meli, Elena; Peruginelli, Fiamma; Pellegrini-Giampietro, Domenico E; Moroni, Flavio

2002-09-01

Kynurenine 3-mono-oxygenase (KMO) inhibitors reduce 3-hydroxykynurenine (3-HK) and quinolinic acid (QUIN) neosynthesis and facilitate kynurenine metabolism towards kynurenic acid (KYNA) formation. They also reduce tissue damage in models of focal or transient global cerebral ischemia in vivo. We used organotypic hippocampal slice cultures exposed to oxygen and glucose deprivation (OGD) to investigate KMO mechanism(s) of neuroprotective activity. Exposure of the slices to 30 min of OGD caused CA1 pyramidal cell death and significantly decreased the amount of KYNA released in the incubation medium. The KMO inhibitors (m-nitrobenzoyl)-alanine (30-100 micro m) or 3,4-dimethoxy-[-N-4-(nitrophenyl)thiazol-2yl]-benzenesulfonamide (1-10 micro m) reduced post-ischemic neuronal death and increased KYNA concentrations in slice incubation media. The maximal concentration of KYNA detected in the incubation media of slices treated with KMO inhibitors was approximately 50 nm and was too low to efficiently interact with alpha7 nicotinic acetylcholine receptors or with the glycineb site of N-methyl-d-aspartate (NMDA) receptors. On the other hand, the addition of either 3-HK or QUIN (1-10 micro m) to OGD-exposed hippocampal slices prevented the neuroprotective activity of KMO inhibitors. Our results suggest that KMO inhibitors reduce the neuronal death found in the CA1 region of organotypic hippocampal slices exposed to 30 min of OGD by decreasing the local synthesis of 3-HK and QUIN.

Adjacent slice prostate cancer prediction to inform MALDI imaging biomarker analysis

NASA Astrophysics Data System (ADS)

Chuang, Shao-Hui; Sun, Xiaoyan; Cazares, Lisa; Nyalwidhe, Julius; Troyer, Dean; Semmes, O. John; Li, Jiang; McKenzie, Frederic D.

2010-03-01

Prostate cancer is the second most common type of cancer among men in US [1]. Traditionally, prostate cancer diagnosis is made by the analysis of prostate-specific antigen (PSA) levels and histopathological images of biopsy samples under microscopes. Proteomic biomarkers can improve upon these methods. MALDI molecular spectra imaging is used to visualize protein/peptide concentrations across biopsy samples to search for biomarker candidates. Unfortunately, traditional processing methods require histopathological examination on one slice of a biopsy sample while the adjacent slice is subjected to the tissue destroying desorption and ionization processes of MALDI. The highest confidence tumor regions gained from the histopathological analysis are then mapped to the MALDI spectra data to estimate the regions for biomarker identification from the MALDI imaging. This paper describes a process to provide a significantly better estimate of the cancer tumor to be mapped onto the MALDI imaging spectra coordinates using the high confidence region to predict the true area of the tumor on the adjacent MALDI imaged slice.

Nitric oxide inhibition of alcohol dehydrogenase in fresh-cut apples ( Malus domestica Borkh).

PubMed

Amissah, Joris Gerald Niilante; Hotchkiss, Joseph H; Watkins, Chris B

2013-11-20

The effects of nitric oxide (NO) and nitrite treatment on alcohol dehydrogenase activity and the shelf life of apple tissue were investigated. Fresh-cut apple slices were stored for 2 days at 6 °C in 0.25-1% NO (v/v, balance N2) or 100% N2 atmospheres. Slices were also treated with 1% NO or 2 mM sodium nitrite (NaNO2) for 20 min, stored for 6 weeks in 100% N2 at 6 °C, and analyzed for acetaldehyde, ethanol, and ethyl acetate accumulation, firmness, and color. Compared with N2 or deionized water controls, treatment with 1% NO or 2 mM NaNO2 inhibited ethanol accumulation, whereas that of acetaldehyde increased. Ethyl acetate accumulation was inhibited only by NO. Slice firmness was not affected by NO or NaNO2 treatment, but slices were darker than the untreated controls. NO and nitrite may extend the shelf life of fresh-cut produce with low concentrations of phenolic compounds.

Pulsed magnetization transfer contrast MRI by a sequence with water selective excitation

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

Schick, F.

1996-01-01

A water selective SE imaging sequence was developed providing suitable properties for the assessment of magnetization transfer (MT) effects in tissues with considerable amounts of fat. The sequence with water selective excitation and slice selective refocusing combines the following features: The RIF exposure on the macromolecular protons is relatively low for single slice imaging without MT prepulses, since no additional pulses for fat saturation are necessary. Water selection by frequency selective excitation diminishes faults in the subtraction of images recorded with and without MT prepulses (which might arise from movements). High differences in the signal amplitudes from hyaline cartilage andmore » muscle tissue were obtained comparing images recorded with irradiation of the series of prepulses for MT and those lacking MT prepulses. Utilizations of the described water selective approach for the assessment of MT effects in lesions of cartilage and bone are demonstrated. MT saturation was also examined in muscles with fatty degeneration of patients suffering from progressive muscular dystrophy. The described technique allows determination of MT effects with good precision in a single slice, especially in regions with dominating fat signals. 22 refs., 5 figs.« less

Protocols and characterization data for 2D, 3D, and slice-based tumor models from the PREDECT project.

PubMed

de Hoogt, Ronald; Estrada, Marta F; Vidic, Suzana; Davies, Emma J; Osswald, Annika; Barbier, Michael; Santo, Vítor E; Gjerde, Kjersti; van Zoggel, Hanneke J A A; Blom, Sami; Dong, Meng; Närhi, Katja; Boghaert, Erwin; Brito, Catarina; Chong, Yolanda; Sommergruber, Wolfgang; van der Kuip, Heiko; van Weerden, Wytske M; Verschuren, Emmy W; Hickman, John; Graeser, Ralph

2017-11-21

Two-dimensional (2D) culture of cancer cells in vitro does not recapitulate the three-dimensional (3D) architecture, heterogeneity and complexity of human tumors. More representative models are required that better reflect key aspects of tumor biology. These are essential studies of cancer biology and immunology as well as for target validation and drug discovery. The Innovative Medicines Initiative (IMI) consortium PREDECT (www.predect.eu) characterized in vitro models of three solid tumor types with the goal to capture elements of tumor complexity and heterogeneity. 2D culture and 3D mono- and stromal co-cultures of increasing complexity, and precision-cut tumor slice models were established. Robust protocols for the generation of these platforms are described. Tissue microarrays were prepared from all the models, permitting immunohistochemical analysis of individual cells, capturing heterogeneity. 3D cultures were also characterized using image analysis. Detailed step-by-step protocols, exemplary datasets from the 2D, 3D, and slice models, and refined analytical methods were established and are presented.

Protocols and characterization data for 2D, 3D, and slice-based tumor models from the PREDECT project

PubMed Central

de Hoogt, Ronald; Estrada, Marta F.; Vidic, Suzana; Davies, Emma J.; Osswald, Annika; Barbier, Michael; Santo, Vítor E.; Gjerde, Kjersti; van Zoggel, Hanneke J. A. A.; Blom, Sami; Dong, Meng; Närhi, Katja; Boghaert, Erwin; Brito, Catarina; Chong, Yolanda; Sommergruber, Wolfgang; van der Kuip, Heiko; van Weerden, Wytske M.; Verschuren, Emmy W.; Hickman, John; Graeser, Ralph

2017-01-01

Two-dimensional (2D) culture of cancer cells in vitro does not recapitulate the three-dimensional (3D) architecture, heterogeneity and complexity of human tumors. More representative models are required that better reflect key aspects of tumor biology. These are essential studies of cancer biology and immunology as well as for target validation and drug discovery. The Innovative Medicines Initiative (IMI) consortium PREDECT (www.predect.eu) characterized in vitro models of three solid tumor types with the goal to capture elements of tumor complexity and heterogeneity. 2D culture and 3D mono- and stromal co-cultures of increasing complexity, and precision-cut tumor slice models were established. Robust protocols for the generation of these platforms are described. Tissue microarrays were prepared from all the models, permitting immunohistochemical analysis of individual cells, capturing heterogeneity. 3D cultures were also characterized using image analysis. Detailed step-by-step protocols, exemplary datasets from the 2D, 3D, and slice models, and refined analytical methods were established and are presented. PMID:29160867

Applying a deep learning based CAD scheme to segment and quantify visceral and subcutaneous fat areas from CT images

NASA Astrophysics Data System (ADS)

Wang, Yunzhi; Qiu, Yuchen; Thai, Theresa; Moore, Kathleen; Liu, Hong; Zheng, Bin

2017-03-01

Abdominal obesity is strongly associated with a number of diseases and accurately assessment of subtypes of adipose tissue volume plays a significant role in predicting disease risk, diagnosis and prognosis. The objective of this study is to develop and evaluate a new computer-aided detection (CAD) scheme based on deep learning models to automatically segment subcutaneous fat areas (SFA) and visceral (VFA) fat areas depicting on CT images. A dataset involving CT images from 40 patients were retrospectively collected and equally divided into two independent groups (i.e. training and testing group). The new CAD scheme consisted of two sequential convolutional neural networks (CNNs) namely, Selection-CNN and Segmentation-CNN. Selection-CNN was trained using 2,240 CT slices to automatically select CT slices belonging to abdomen areas and SegmentationCNN was trained using 84,000 fat-pixel patches to classify fat-pixels as belonging to SFA or VFA. Then, data from the testing group was used to evaluate the performance of the optimized CAD scheme. Comparing to manually labelled results, the classification accuracy of CT slices selection generated by Selection-CNN yielded 95.8%, while the accuracy of fat pixel segmentation using Segmentation-CNN yielded 96.8%. Therefore, this study demonstrated the feasibility of using deep learning based CAD scheme to recognize human abdominal section from CT scans and segment SFA and VFA from CT slices with high agreement compared with subjective segmentation results.

Photon Entanglement Through Brain Tissue

PubMed Central

Shi, Lingyan; Galvez, Enrique J.; Alfano, Robert R.

2016-01-01

Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue. By spatially filtering the ballistic scattering of an entangled photon, we find that its polarization entanglement is preserved and non-locally correlated with its twin in the TS plots. The degree of entanglement correlates better with structure and water content than with sample thickness. PMID:27995952

Precision Cut Mouse Lung Slices to Visualize Live Pulmonary Dendritic Cells

PubMed Central

Lyons-Cohen, Miranda R.; Thomas, Seddon Y.; Cook, Donald N.; Nakano, Hideki

2017-01-01

SHORT ABSTRACT We describe a method for generating precision-cut lung slices (PCLS) and immunostaining them to visualize the localization of various immune cell types in the lung. Our protocol can be extended to visualize the location and function of many different cell types under a variety of conditions. LONG ABSTRACT Inhalation of allergens and pathogens elicits multiple changes in a variety of immune cell types in the lung. Flow cytometry is a powerful technique for quantitative analysis of cell surface proteins on immune cells, but it provides no information on the localization and migration patterns of these cells within the lung. Similarly, in vitro chemotaxis assays can be performed to study the potential of cells to respond to chemotactic factors in vitro, but these assays do not reproduce the complex environment of the intact lung. In contrast to these aforementioned techniques, the location of individual cell types within the lung can be readily visualized by generating precision-cut lung slices (PCLS), staining them with commercially available, fluorescently tagged antibodies, and visualizing the sections by confocal microscopy. PCLS can be used for both live and fixed lung tissue, and the slices can encompass areas as large as a cross section of an entire lobe. We have used this protocol to successfully visualize the location of a wide variety of cell types in the lung, including distinct types of dendritic cells, macrophages, neutrophils, T cells and B cells, as well as structural cells such as lymphatic, endothelial, and epithelial cells. The ability to visualize cellular interactions, such as those between dendritic cells and T cells, in live, three-dimensional lung tissue, can reveal how cells move within the lung and interact with one another at steady state and during inflammation. Thus, when used in combination with other procedures, such as flow cytometry and quantitative PCR, PCLS can contribute to a comprehensive understanding of cellular events that underlie allergic and inflammatory diseases of the lung. PMID:28448013

Scanning X-ray diffraction on cardiac tissue: automatized data analysis and processing.

PubMed

Nicolas, Jan David; Bernhardt, Marten; Markus, Andrea; Alves, Frauke; Burghammer, Manfred; Salditt, Tim

2017-11-01

A scanning X-ray diffraction study of cardiac tissue has been performed, covering the entire cross section of a mouse heart slice. To this end, moderate focusing by compound refractive lenses to micrometer spot size, continuous scanning, data acquisition by a fast single-photon-counting pixel detector, and fully automated analysis scripts have been combined. It was shown that a surprising amount of structural data can be harvested from such a scan, evaluating the local scattering intensity, interfilament spacing of the muscle tissue, the filament orientation, and the degree of anisotropy. The workflow of data analysis is described and a data analysis toolbox with example data for general use is provided. Since many cardiomyopathies rely on the structural integrity of the sarcomere, the contractile unit of cardiac muscle cells, the present study can be easily extended to characterize tissue from a diseased heart.

A novel slice preparation to study medullary oromotor and autonomic circuits in vitro

PubMed Central

Nasse, Jason S.

2014-01-01

Background The medulla is capable of controlling and modulating ingestive behavior and gastrointestinal function. These two functions, which are critical to maintaining homeostasis, are governed by an interconnected group of nuclei dispersed throughout the medulla. As such, in vitro experiments to study the neurophysiologic details of these connections have been limited by spatial constraints of conventional slice preparations. New method This study demonstrates a novel method of sectioning the medulla so that sensory, integrative, and motor nuclei that innervate the gastrointestinal tract and the oral cavity remain intact. Results: Immunohistochemical staining against choline-acetyl-transferase and dopamine-β-hydroxylase demonstrated that within a 450 μm block of tissue we are able to capture sensory, integrative and motor nuclei that are critical to oromotor and gastrointestinal function. Within slice tracing shows that axonal projections from the NST to the reticular formation and from the reticular formation to the hypoglossal motor nucleus (mXII) persist. Live-cell calcium imaging of the slice demonstrates that stimulation of either the rostral or caudal NST activates neurons throughout the NST, as well as the reticular formation and mXII. Comparison with existing methods This new method of sectioning captures a majority of the nuclei that are active when ingesting a meal. Tradition planes of section, i.e. coronal, horizontal or sagittal, contain only a limited portion of the substrate. Conclusions Our results demonstrate that both anatomical and physiologic connections of oral and visceral sensory nuclei that project to integrative and motor nuclei remain intact with this new plane of section. PMID:25196216

A novel slice preparation to study medullary oromotor and autonomic circuits in vitro.

PubMed

Nasse, Jason S

2014-11-30

The medulla is capable of controlling and modulating ingestive behavior and gastrointestinal function. These two functions, which are critical to maintaining homeostasis, are governed by an interconnected group of nuclei dispersed throughout the medulla. As such, in vitro experiments to study the neurophysiologic details of these connections have been limited by spatial constraints of conventional slice preparations. This study demonstrates a novel method of sectioning the medulla so that sensory, integrative, and motor nuclei that innervate the gastrointestinal tract and the oral cavity remain intact. Immunohistochemical staining against choline-acetyl-transferase and dopamine-β-hydroxylase demonstrated that within a 450 μm block of tissue we are able to capture sensory, integrative and motor nuclei that are critical to oromotor and gastrointestinal function. Within slice tracing shows that axonal projections from the NST to the reticular formation and from the reticular formation to the hypoglossal motor nucleus (mXII) persist. Live-cell calcium imaging of the slice demonstrates that stimulation of either the rostral or caudal NST activates neurons throughout the NST, as well as the reticular formation and mXII. This new method of sectioning captures a majority of the nuclei that are active when ingesting a meal. Tradition planes of section, i.e. coronal, horizontal or sagittal, contain only a limited portion of the substrate. Our results demonstrate that both anatomical and physiologic connections of oral and visceral sensory nuclei that project to integrative and motor nuclei remain intact with this new plane of section. Published by Elsevier B.V.

Cell Membrane Tracking in Living Brain Tissue Using Differential Interference Contrast Microscopy.

PubMed

Lee, John; Kolb, Ilya; Forest, Craig R; Rozell, Christopher J

2018-04-01

Differential interference contrast (DIC) microscopy is widely used for observing unstained biological samples that are otherwise optically transparent. Combining this optical technique with machine vision could enable the automation of many life science experiments; however, identifying relevant features under DIC is challenging. In particular, precise tracking of cell boundaries in a thick ( ) slice of tissue has not previously been accomplished. We present a novel deconvolution algorithm that achieves the state-of-the-art performance at identifying and tracking these membrane locations. Our proposed algorithm is formulated as a regularized least squares optimization that incorporates a filtering mechanism to handle organic tissue interference and a robust edge-sparsity regularizer that integrates dynamic edge tracking capabilities. As a secondary contribution, this paper also describes new community infrastructure in the form of a MATLAB toolbox for accurately simulating DIC microscopy images of in vitro brain slices. Building on existing DIC optics modeling, our simulation framework additionally contributes an accurate representation of interference from organic tissue, neuronal cell-shapes, and tissue motion due to the action of the pipette. This simulator allows us to better understand the image statistics (to improve algorithms), as well as quantitatively test cell segmentation and tracking algorithms in scenarios, where ground truth data is fully known.

Gravity Vector Changes Induce Alterations in Nervous and Testicular Cells in Cultures and in Testis Slices

NASA Astrophysics Data System (ADS)

Uva, B.; Strollo, F.; Ricci, F.; Masini, M. A.

Cultured astrocytes, neurons and testicular cells (myoid, germ, Sertoli, Leydig cells) as well as rat testes and testes'slices, were subjected to modeled microgravity using a three dimensional Random Positioning Machine (10-6G) for 5min, 30min, 1h, 24h and 32h. Parallel cell cultures and tissues were submitted to hypergravity using an hyperfuge (2.5G) for the same period of time. At the end of the rotations the cultures and tissues were fixed, the tissue was sectioned (5 micron). All the specimens were processed for immunohistochemical identification of microtubules, mitochondria, 3 hydroxysteroid dehydrogenase, 17 hydroxysteroid dehydrogenase, caspase 7, heat shock proteins and identification of DNA fragmentation. At 5min at modeled microgravity and hypergravity, the histology of the cells in culture and the tissues was altered, microtubules and mitochondria were disorganized. Numerous cells underwent apoptosis. Immunostaining for enzymes involved in ion transmembrane transport, as Na+/K+ATPase and cotransporter proteins, and in steroidogenesis diminished or was abolished. At 1h in modeled microgravity or hypergravity, HSPs were expressed and ion transport enzymes as well as steroidogenic enzymes were again immunostainable. These data show that microgravity and hypergravity cause only transient alterations, and tissues and cells in cultures are able to adapt to different gravity conditions.

Preparation and fabrication of a full-scale, sagittal-sliced, 3D-printed, patient-specific radiotherapy phantom.

PubMed

Craft, Daniel F; Howell, Rebecca M

2017-09-01

Patient-specific 3D-printed phantoms have many potential applications, both research and clinical. However, they have been limited in size and complexity because of the small size of most commercially available 3D printers as well as material warping concerns. We aimed to overcome these limitations by developing and testing an effective 3D printing workflow to fabricate a large patient-specific radiotherapy phantom with minimal warping errors. In doing so, we produced a full-scale phantom of a real postmastectomy patient. We converted a patient's clinical CT DICOM data into a 3D model and then sliced the model into eleven 2.5-cm-thick sagittal slices. The slices were printed with a readily available thermoplastic material representing all body tissues at 100% infill, but with air cavities left open. Each slice was printed on an inexpensive and commercially available 3D printer. Once the printing was completed, the slices were placed together for imaging and verification. The original patient CT scan and the assembled phantom CT scan were registered together to assess overall accuracy. The materials for the completed phantom cost $524. The printed phantom agreed well with both its design and the actual patient. Individual slices differed from their designs by approximately 2%. Registered CT images of the assembled phantom and original patient showed excellent agreement. Three-dimensional printing the patient-specific phantom in sagittal slices allowed a large phantom to be fabricated with high accuracy. Our results demonstrate that our 3D printing workflow can be used to make large, accurate, patient-specific phantoms at 100% infill with minimal material warping error. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Abscisic Acid Accumulation in Spinach Leaf Slices in the Presence of Penetrating and Nonpenetrating Solutes 1

PubMed Central

Creelman, Robert A.; Zeevaart, Jan A. D.

1985-01-01

Abscisic acid (ABA) accumulated in detached, wilted leaves of spinach (Spinacia oleracea L. cv Savoy Hybrid 612) and reached a maximum level within 3 to 4 hours. The increase in ABA over that found in detached turgid leaves was approximately 10-fold. The effects of water stress could be mimicked by the use of thin slices of spinach leaves incubated in the presence of 0.6 molar mannitol, a compound which causes plasmolysis (loss of turgor). About equal amounts of ABA were found both in the leaf slices and in detached leaves, whereas 2 to 4 times more ABA accumulated in the medium than in the slices. When spinach leaf slices were incubated with ethylene glycol, a compound which rapidly penetrates the cell membrane causing a decrease in the osmotic potential of the tissue and only transient loss of turgor, no ABA accumulated. Ethylene glycol was not inhibitory with respect to ABA accumulation. Spinach leaf slices incubated in both ethylene glycol and mannitol had ABA levels similar to those found when slices were incubated with mannitol alone. Increases similar to those found with mannitol also occurred when Aquacide III, a highly purified form of polyethylene glycol, was used. Aquacide III causes cytorrhysis, a situation similar to that found in wilted leaves. Thus, it appears that loss of turgor is essential for ABA accumulation. When spinach leaf slices were incubated with solutes which are supposed to disturb membrane integrity (KHSO3, 2-propanol, or KCl) no increase in ABA was observed. These data indicate that, with respect to the accumulation of ABA, mannitol caused a physical stress (loss of turgor) rather than a chemical stress (membrane damage). PMID:16664022

Abscisic Acid accumulation in spinach leaf slices in the presence of penetrating and nonpenetrating solutes.

PubMed

Creelman, R A; Zeevaart, J A

1985-01-01

Abscisic acid (ABA) accumulated in detached, wilted leaves of spinach (Spinacia oleracea L. cv Savoy Hybrid 612) and reached a maximum level within 3 to 4 hours. The increase in ABA over that found in detached turgid leaves was approximately 10-fold. The effects of water stress could be mimicked by the use of thin slices of spinach leaves incubated in the presence of 0.6 molar mannitol, a compound which causes plasmolysis (loss of turgor). About equal amounts of ABA were found both in the leaf slices and in detached leaves, whereas 2 to 4 times more ABA accumulated in the medium than in the slices. When spinach leaf slices were incubated with ethylene glycol, a compound which rapidly penetrates the cell membrane causing a decrease in the osmotic potential of the tissue and only transient loss of turgor, no ABA accumulated. Ethylene glycol was not inhibitory with respect to ABA accumulation. Spinach leaf slices incubated in both ethylene glycol and mannitol had ABA levels similar to those found when slices were incubated with mannitol alone. Increases similar to those found with mannitol also occurred when Aquacide III, a highly purified form of polyethylene glycol, was used. Aquacide III causes cytorrhysis, a situation similar to that found in wilted leaves. Thus, it appears that loss of turgor is essential for ABA accumulation.When spinach leaf slices were incubated with solutes which are supposed to disturb membrane integrity (KHSO(3), 2-propanol, or KCl) no increase in ABA was observed. These data indicate that, with respect to the accumulation of ABA, mannitol caused a physical stress (loss of turgor) rather than a chemical stress (membrane damage).

Techniques A: continuous waves

NASA Astrophysics Data System (ADS)

Beuthan, J.

1993-08-01

In a vast amount of medical diseases the biochemical and physiological changes of soft tissues are hardly detectable by conventional techniques of diagnostic imaging (x- ray, ultrasound, computer tomography, and MRI). The detectivity is low and the technical efforts are tremendous. On the other hand these pathologic variations induce significant changes of the optical tissue parameters which can be detected. The corresponding variations of the scattered light can most easily be detected and evaluated by infrared diaphanoscopy, even on optical thick tissue slices.

Effects of vitrification cryopreservation on follicular morphology and stress relaxation behaviors of human ovarian tissues: sucrose versus trehalose as the non-permeable protective agent.

PubMed

Tian, Ting; Zhao, Gang; Han, Dan; Zhu, Kaixuan; Chen, Dawei; Zhang, Zhiguo; Wei, Zhaolian; Cao, Yunxia; Zhou, Ping

2015-04-01

Is sucrose more effective than trehalose in human ovarian tissue cryopreservation? The effect of sucrose as a cryoprotective agent (CPA) was not significantly different from that of trehalose in human ovarian tissue cryopreservation. Sugars have the ability to keep the cell membrane intact and can decrease the toxicity of CPAs. Sucrose is the most commonly used non-permeable CPA, while trehalose is rarely used in human ovarian tissue cryopreservation. Although various methods are utilized to evaluate the efficiency of human ovarian tissue cryopreservation, few studies have evaluated the effect of cryopreservation from the viewpoint of biomechanics. A total of 15 ovarian tissue samples were collected from 15 patients (20-41 years old) with benign ovarian tumors or malignancies, and each was dissected into six slices. Two slices were taken as the fresh control group. The remaining four slices were vitrified using different vitrification protocols. After warming, samples in each group were either fixed for histological evaluation or destined for stress relaxation test. The CPA solutions for the control and vitrified groups were composed of EDS and EDT (E, ethylene glycol; D, dimethylsulphoxide; S, sucrose; T, trehalose). The stress relaxation experiments were carried out at room temperature using a dynamic mechanical analyzer. Ovarian tissue samples were assessed for both their morphology and viscoelasticity. Stress relaxation data (SRD) were calculated as a percentage, representing the ability to maintain the initial stress after stretching. The percentage of morphologically normal follicles was compared between groups, which was represented by morphologic preservation ratio. The morphologic preservation ratio of the primordial follicles in the fresh control group (87.58%) was higher than that in group S (72.33%) (P = 0.000) and group T (79.56%) (P = 0.002). Although not statistically significant, compared with the S group, vitrification with T suggested a trend toward a higher morphologic preservation ratio of the primordial follicles. The SRD in the fresh control group (0.6433 ± 0.7233) was significantly different from that in group S (0.5200 ± 0.8331, P = 0.000) or in group T (0.5667 ± 0.6415, P = 0.000). However, no significant difference was found between groups S and T. Experimental samples were directly exposed to the air, which will result in a discrepancy in the viscoelastic properties between experimental tissues and in vivo tissues. Our study suggested a trend toward a higher morphologic preservation ratio of the primordial follicles after vitrification in trehalose compared with sucrose, which may provide a basis for further optimizing human ovarian tissue vitrification. In addition, it was possible to evaluate the effect of ovarian tissue cryopreservation from a biomechanics perspective. This study was supported by the grants from the Medical Scientific Research Subject, Health Ministry of Anhui Province (2010B014) and National Basic Research Program of China (973 Program) (2012CB944704), and the National Natural Science Foundation of China (Nos. 51276179 and 51476160). The authors declare that there is no conflict of interests regarding the publication of this original paper. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Automated fibroglandular tissue segmentation and volumetric density estimation in breast MRI using an atlas-aided fuzzy C-means method

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

Wu, Shandong; Weinstein, Susan P.; Conant, Emily F.

Purpose: Breast magnetic resonance imaging (MRI) plays an important role in the clinical management of breast cancer. Studies suggest that the relative amount of fibroglandular (i.e., dense) tissue in the breast as quantified in MR images can be predictive of the risk for developing breast cancer, especially for high-risk women. Automated segmentation of the fibroglandular tissue and volumetric density estimation in breast MRI could therefore be useful for breast cancer risk assessment. Methods: In this work the authors develop and validate a fully automated segmentation algorithm, namely, an atlas-aided fuzzy C-means (FCM-Atlas) method, to estimate the volumetric amount of fibroglandularmore » tissue in breast MRI. The FCM-Atlas is a 2D segmentation method working on a slice-by-slice basis. FCM clustering is first applied to the intensity space of each 2D MR slice to produce an initial voxelwise likelihood map of fibroglandular tissue. Then a prior learned fibroglandular tissue likelihood atlas is incorporated to refine the initial FCM likelihood map to achieve enhanced segmentation, from which the absolute volume of the fibroglandular tissue (|FGT|) and the relative amount (i.e., percentage) of the |FGT| relative to the whole breast volume (FGT%) are computed. The authors' method is evaluated by a representative dataset of 60 3D bilateral breast MRI scans (120 breasts) that span the full breast density range of the American College of Radiology Breast Imaging Reporting and Data System. The automated segmentation is compared to manual segmentation obtained by two experienced breast imaging radiologists. Segmentation performance is assessed by linear regression, Pearson's correlation coefficients, Student's pairedt-test, and Dice's similarity coefficients (DSC). Results: The inter-reader correlation is 0.97 for FGT% and 0.95 for |FGT|. When compared to the average of the two readers’ manual segmentation, the proposed FCM-Atlas method achieves a correlation ofr = 0.92 for FGT% and r = 0.93 for |FGT|, and the automated segmentation is not statistically significantly different (p = 0.46 for FGT% and p = 0.55 for |FGT|). The bilateral correlation between left breasts and right breasts for the FGT% is 0.94, 0.92, and 0.95 for reader 1, reader 2, and the FCM-Atlas, respectively; likewise, for the |FGT|, it is 0.92, 0.92, and 0.93, respectively. For the spatial segmentation agreement, the automated algorithm achieves a DSC of 0.69 ± 0.1 when compared to reader 1 and 0.61 ± 0.1 for reader 2, respectively, while the DSC between the two readers’ manual segmentation is 0.67 ± 0.15. Additional robustness analysis shows that the segmentation performance of the authors' method is stable both with respect to selecting different cases and to varying the number of cases needed to construct the prior probability atlas. The authors' results also show that the proposed FCM-Atlas method outperforms the commonly used two-cluster FCM-alone method. The authors' method runs at ∼5 min for each 3D bilateral MR scan (56 slices) for computing the FGT% and |FGT|, compared to ∼55 min needed for manual segmentation for the same purpose. Conclusions: The authors' method achieves robust segmentation and can serve as an efficient tool for processing large clinical datasets for quantifying the fibroglandular tissue content in breast MRI. It holds a great potential to support clinical applications in the future including breast cancer risk assessment.« less

Automated fibroglandular tissue segmentation and volumetric density estimation in breast MRI using an atlas-aided fuzzy C-means method

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

Wu, Shandong; Weinstein, Susan P.; Conant, Emily F.

2013-12-15

Purpose: Breast magnetic resonance imaging (MRI) plays an important role in the clinical management of breast cancer. Studies suggest that the relative amount of fibroglandular (i.e., dense) tissue in the breast as quantified in MR images can be predictive of the risk for developing breast cancer, especially for high-risk women. Automated segmentation of the fibroglandular tissue and volumetric density estimation in breast MRI could therefore be useful for breast cancer risk assessment. Methods: In this work the authors develop and validate a fully automated segmentation algorithm, namely, an atlas-aided fuzzy C-means (FCM-Atlas) method, to estimate the volumetric amount of fibroglandularmore » tissue in breast MRI. The FCM-Atlas is a 2D segmentation method working on a slice-by-slice basis. FCM clustering is first applied to the intensity space of each 2D MR slice to produce an initial voxelwise likelihood map of fibroglandular tissue. Then a prior learned fibroglandular tissue likelihood atlas is incorporated to refine the initial FCM likelihood map to achieve enhanced segmentation, from which the absolute volume of the fibroglandular tissue (|FGT|) and the relative amount (i.e., percentage) of the |FGT| relative to the whole breast volume (FGT%) are computed. The authors' method is evaluated by a representative dataset of 60 3D bilateral breast MRI scans (120 breasts) that span the full breast density range of the American College of Radiology Breast Imaging Reporting and Data System. The automated segmentation is compared to manual segmentation obtained by two experienced breast imaging radiologists. Segmentation performance is assessed by linear regression, Pearson's correlation coefficients, Student's pairedt-test, and Dice's similarity coefficients (DSC). Results: The inter-reader correlation is 0.97 for FGT% and 0.95 for |FGT|. When compared to the average of the two readers’ manual segmentation, the proposed FCM-Atlas method achieves a correlation ofr = 0.92 for FGT% and r = 0.93 for |FGT|, and the automated segmentation is not statistically significantly different (p = 0.46 for FGT% and p = 0.55 for |FGT|). The bilateral correlation between left breasts and right breasts for the FGT% is 0.94, 0.92, and 0.95 for reader 1, reader 2, and the FCM-Atlas, respectively; likewise, for the |FGT|, it is 0.92, 0.92, and 0.93, respectively. For the spatial segmentation agreement, the automated algorithm achieves a DSC of 0.69 ± 0.1 when compared to reader 1 and 0.61 ± 0.1 for reader 2, respectively, while the DSC between the two readers’ manual segmentation is 0.67 ± 0.15. Additional robustness analysis shows that the segmentation performance of the authors' method is stable both with respect to selecting different cases and to varying the number of cases needed to construct the prior probability atlas. The authors' results also show that the proposed FCM-Atlas method outperforms the commonly used two-cluster FCM-alone method. The authors' method runs at ∼5 min for each 3D bilateral MR scan (56 slices) for computing the FGT% and |FGT|, compared to ∼55 min needed for manual segmentation for the same purpose. Conclusions: The authors' method achieves robust segmentation and can serve as an efficient tool for processing large clinical datasets for quantifying the fibroglandular tissue content in breast MRI. It holds a great potential to support clinical applications in the future including breast cancer risk assessment.« less

Imaging of oxygenation in 3D tissue models with multi-modal phosphorescent probes

NASA Astrophysics Data System (ADS)

Papkovsky, Dmitri B.; Dmitriev, Ruslan I.; Borisov, Sergei

2015-03-01

Cell-penetrating phosphorescence based probes allow real-time, high-resolution imaging of O2 concentration in respiring cells and 3D tissue models. We have developed a panel of such probes, small molecule and nanoparticle structures, which have different spectral characteristics, cell penetrating and tissue staining behavior. The probes are compatible with conventional live cell imaging platforms and can be used in different detection modalities, including ratiometric intensity and PLIM (Phosphorescence Lifetime IMaging) under one- or two-photon excitation. Analytical performance of these probes and utility of the O2 imaging method have been demonstrated with different types of samples: 2D cell cultures, multi-cellular spheroids from cancer cell lines and primary neurons, excised slices from mouse brain, colon and bladder tissue, and live animals. They are particularly useful for hypoxia research, ex-vivo studies of tissue physiology, cell metabolism, cancer, inflammation, and multiplexing with many conventional fluorophors and markers of cellular function.

Computer aided three-dimensional reconstruction and modeling of the pelvis, by using plastinated cross sections, as a powerful tool for morphological investigations.

PubMed

Sora, Mircea-Constantin; Jilavu, Radu; Matusz, Petru

2012-10-01

The aim of this study was to describe a method of developing a computerized model of the human female pelvis using plastinated slices. Computerized reconstruction of anatomical structures is becoming very useful for developing anatomical teaching, research modules and animations. Although databases consisting of serial sections derived from frozen cadaver material exist, plastination represents an alternative method for developing anatomical data useful for computerized reconstruction. A slice anatomy study, using plastinated transparent pelvis cross sections, was performed to obtain a 3D reconstruction. One female human pelvis used for this study, first plastinated as a block, then sliced into thin slices and in the end subjected to 3D computerized reconstruction using WinSURF modeling system (SURFdriver Software). To facilitate the understanding of the complex pelvic floor anatomy on sectional images obtained through MR imaging, and to make the representation more vivid, a female pelvis computer-aided 3D model was created. Qualitative observations revealed that the morphological features of the model were consistent with those displayed by typical cadaveric specimens. The quality of the reconstructed images appeared distinct, especially the spatial positions and complicated relationships of contiguous structures of the female pelvis. All reconstructed structures can be displayed in groups or as a whole and interactively rotated in 3D space. The utilization of plastinates for generating tissue sections is useful for 3D computerized modeling. The 3D model of the female pelvis presented in this paper provides a stereoscopic view to study the adjacent relationship and arrangement of respective pelvis sections. A better understanding of the pelvic floor anatomy is relevant to gynaecologists, radiologists, surgeons, urologists, physical therapists and all professionals who take care of women with pelvic floor dysfunction.

Notochord isolation using laser capture microdissection.

PubMed

Santegoeds, R G C; Yakkioui, Y; Jahanshahi, A; Raven, G; Van Overbeeke, J J; Herrler, A; Temel, Y

2017-03-01

Chordoma are malignant tumors of the axial skeleton, which arise from remnants of the notochord. The Notochord (chorda dorsalis) is an essential embryonic structure involved in the development of the nervous system and axial skeleton. Therefore, the notochord seems to be the most biologically relevant control tissue to study chordoma in molecular biology research. Nevertheless, up to now mainly different tissues but not the notochord have been used as control for chordoma, due to difficulty of isolating notochordal tissue. Here, we describe a fast and precise method of isolating notochordal cells. Examination of human fetuses, with a gestation of 9, 11 and 13 weeks, using (immuno)histochemical methods was performed. To isolate pure notochord cells for further molecular biology investigation five flash frozen fetuses between 9 and 10 weeks of gestation were dissected by microtome slicing. Thereafter pure notochord cells for further molecular biology investigation where harvested by using laser capture microdissection (LCM). RNA was extracted from these samples and used in quantitative PCR. This study illustrates notochord of embryonic spines in three different stages of gestation (9-11-13 weeks). Immunohistochemical staining with brachyury showed strong staining of the notochord, but also weak staining of the intervertebral disc and vertebral body. LCM of notochord slices and subsequent total RNA extraction resulted in a good yield of total RNA. qPCR analysis of two housekeeping genes confirmed the quality of the RNA. LCM is a fast and precise method to isolate notochord and the quality and yield RNA extracted from this tissue is sufficient for qPCR analysis. Therefore early embryo notochord isolated by LCM is suggested to be the gold standard for future research in chordoma development, classification and diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

PIXE analysis of mineral matter in thin sections of human lung

NASA Astrophysics Data System (ADS)

Annegarn, H. J.; Pillay, A. E.; Da Vies, J. C. A.; Faure, D.; Sellschop, J. P. F.

1988-12-01

It is postulated that insoluble mineral residues in the lungs of deceased miners may provide a quantitative measure of the integrated lifetime dust exposure. For epidemiological surveys rapid instrumental techniques are required to analyse representative samples of lung tissue. Particle-induced X-ray emission (PIXE) has been evaluated for analysis of microtomed slices of wax-embedded lung and lymph node (Hilar gland) tissue from deceased miners. The 50 μm slices, mounted on Mylar backings and placed in a He atmosphere, were irradiated using 3.2 MeV protons. PIXE analysis provided adequate sensitivity for key mineral elements including Si, Cr and Ti. The porous, nonuniform nature of lung tissue made it impossible to measure the tissue mass in the irradiated area, preventing the calculation of mass concentrations. Instead, biological sulphur was used as an internal standard, assuming that the fraction of S in soft, fat-free tissue is constant. Results are presented for lung and lymph node tissue from gold, chrome, copper, platinum and asbestos miners. Si mineral residues in lymph node tissue were found to be concentrated by a factor 50 relative to lung. Cr residues were clearly observed in the chrome miner's lung, but no excess of Cu was present in the copper miner's lung. There is evidence of preferential Si removal relative to Ti. Results warrant further development of PIXE for scanning of large numbers of lung samples prepared in the above manner.

Distinguishing splanchnic nerve and chromaffin cell stimulation in mouse adrenal slices with fast-scan cyclic voltammetry

PubMed Central

Walsh, Paul L.; Petrovic, Jelena

2011-01-01

Electrical stimulation is an indispensible tool in studying electrically excitable tissues in neurobiology and neuroendocrinology. In this work, the consequences of high-intensity electrical stimulation on the release of catecholamines from adrenal gland slices were examined with fast-scan cyclic voltammetry at carbon fiber microelectrodes. A biphasic signal, consisting of a fast and slow phase, was observed when electrical stimulations typically used in tissue slices (10 Hz, 350 μA biphasic, 2.0 ms/phase pulse width) were applied to bipolar tungsten-stimulating electrodes. This signal was found to be stimulation dependent, and the slow phase of the signal was abolished when smaller (≤250 μA) and shorter (1 ms/phase) stimulations were used. The slow phase of the biphasic signal was found to be tetrodotoxin and hexamethonium independent, while the fast phase was greatly reduced using these pharmacological agents. Two different types of calcium responses were observed, where the fast phase was abolished by perfusion with a low-calcium buffer while both the fast and slow phases could be modulated when Ca2+ was completely excluded from the solution using EGTA. Perfusion with nifedipine resulted in the reduction of the slow catecholamine release to 29% of the original signal, while the fast phase was only decreased to 74% of predrug values. From these results, it was determined that high-intensity stimulations of the adrenal medulla result in depolarizing not only the splanchnic nerves, but also the chromaffin cells themselves resulting in a biphasic catecholamine release. PMID:21048165

Effect of vitro preservation on mechanical properties of brain tissue

NASA Astrophysics Data System (ADS)

Zhang, Wei; Liu, Yi-fan; Liu, Li-fu; Niu, Ying; Ma, Jian-li; Wu, Cheng-wei

2017-05-01

To develop the protective devices for preventing traumatic brain injuries, it requires the accurate characterization of the mechanical properties of brain tissue. For this, it necessary to elucidate the effect of vitro preservation on the mechanical performance of brain tissue as usually the measurements are carried out in vitro. In this paper, the thermal behavior of brain tissue preserved for various period of time was first investigated and the mechanical properties were also measured. Both reveals the deterioration with prolonged preservation duration. The observations of brain tissue slices indicates the brain tissue experiences karyorrhexis and karyorrhexis in sequence, which accounts for the deterioration phenomena.

Chronic nicotine administration differentially affects neurotransmitter release from rat striatal slices.

PubMed

Yu, Z J; Wecker, L

1994-07-01

The objective of these experiments was to determine whether the chronic administration of nicotine, at a dose regimen that increases the density of nicotine binding sites, alters the nicotine-induced release of [3H]-dopamine ([3H]DA), [3H]norepinephrine ([3H]NE), [3H]-serotonin ([3H]5-HT), or [3H]acetylcholine ([3H]ACh) from rat striatal slices. For these experiments, rats received subcutaneous injections of either saline or nicotine bitartrate [1.76 mg (3.6 mumol)/kg, dissolved in saline] twice daily for 10 days, and neurotransmitter release was measured following preloading of the tissues with [3H]DA, [3H]NE, [3H]5-HT, or [3H]choline. Chronic nicotine administration did not affect the accumulation of tritium by striatal slices, the basal release of radioactivity, or the 25 mM KCl-evoked release of neurotransmitter. Superfusion of striatal slices with 1, 10, and 100 microM nicotine increased [3H]DA release in a concentration-dependent manner, and release from slices from nicotine-injected animals was significantly (p < 0.05) greater than release from saline-injected controls; release from the former increased to 132, 191, and 172% of release from the controls following superfusion with 1, 10, and 100 microM nicotine, respectively. Similarly, [3H]5-HT release increased in a concentration-related manner following superfusion with nicotine, and release from slices from nicotine-injected rats was significantly (p < 0.05) greater than that from controls. [3H]5-HT release from slices from nicotine-injected rats evoked by superfusion with 1 and 10 microM nicotine increased to 453 and 217%, respectively, of release from slices from saline-injected animals. The nicotine-induced release of [3H]NE from striatal slices was also concentration dependent but was unaffected by chronic nicotine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance assessment of dynamic spiral scan modes with variable pitch for quantitative perfusion computed tomography.

PubMed

Haberland, Ulrike; Klotz, Ernst; Abolmaali, Nasreddin

2010-07-01

Perfusion computed tomography is increasingly being used in diagnostic radiology. Axial coverage of the traditional approach is limited to the width of the detector. Using continuous periodic table movement coverage can be increased beyond this limit. In this study, we compared tissue flow values determined from scans with a periodic spiral implementation with variable pitch with ones determined from standard dynamic scan modes. A flow phantom (preserved porcine kidney) was scanned with 2 settings of a periodic spiral (Adaptive 4D Spiral) with a range of 100 and 148 mm and a temporal sampling of 1.5 seconds. Additionally, the whole phantom was scanned with the standard dynamic mode (detector width 38.4 mm, temporal sampling 1.0 seconds) at various overlapping positions as a reference. Scan parameters (80 kV, 140 mAs, 40s scan time) were selected similar to a typical brain perfusion study. All scans were repeated 5 times. Tissue flow was calculated with a dedicated deconvolution algorithm. In a center slice and 3 additional slices at various off center positions flow values were recorded in a total of 126 regions of interest (ROI). Reproducibility was determined from the variation of the repeat scans. Agreement between periodic spirals and standard mode was determined by Bland Altman plots and correlation analysis. The reproducibility of the tissue flow determination ranged from 2.7 to 4.4 mL/100 mL/min and was similar for all scan modes. The coefficient of variation ranged from 3.9% to 6.1%. Mean tissue flow in the 126 ROIs ranged from 35 to 121 mL/100 mL/min. There was excellent correlation between both periodic spiral ranges and the standard dynamic mode with a Pearson correlation coefficient of r = 0.97. The regression slope (intercept 0) for the 100 mm range was 1.01, for the 148 mm range it was 0.97. The absolute differences per ROI varied between 1.5 and 4.1 mL/100 mL/min, the relative differences between 1.9% and 6.5%. Differences did not depend on the slice location. Periodic spiral scan modes with variable pitch and a sampling rate of 1.5 seconds can be used for the quantitative determination of tissue flow. Their performance is equivalent to equidistant sampling with standard dynamic scan modes. The ranges of 100 and 148 mm investigated allow coverage of the whole brain or an entire organ for perfusion imaging.

Spatially offset Raman spectroscopy for photon migration investigations in long bone

NASA Astrophysics Data System (ADS)

Sowoidnich, Kay; Churchwell, John H.; Buckley, Kevin; Kerns, Jemma G.; Goodship, Allen E.; Parker, Anthony W.; Matousek, Pavel

2015-07-01

Raman Spectroscopy has become an important technique for assessing the composition of excised sections of bone, and is currently being developed as an in vivo tool for transcutaneous detection of bone disease using spatially offset Raman spectroscopy (SORS). The sampling volume of the Raman technique (and thus the amount of bone material interrogated by SORS) depends on the nature of the photon scattering in the probed tissue. Bone is a complex hierarchical material and to date little is known regarding its diffuse scattering properties which are important for the development and optimization of SORS as a diagnostic tool for characterizing bone disease in vivo. SORS measurements at 830 nm excitation wavelength are carried out on stratified samples to determine the depth from which the Raman signal originates within bone tissue. The measurements are made using a 0.38 mm thin Teflon slice, to give a pronounced and defined spectral signature, inserted in between layers of stacked 0.60 mm thin equine bone slices. Comparing the stack of bone slices with and without underlying bone section below the Teflon slice illustrated that thin sections of bone can lose appreciable number of photons through the unilluminated back surface. The results show that larger SORS offsets lead to progressively larger penetration depth into the sample; different Raman spectral signatures could be retrieved through up to 3.9 mm of overlying bone material with a 7 mm offset. These findings have direct impact on potential diagnostic medical applications; for instance on the detection of bone tumors or areas of infected bone.

Quantification of human body fat tissue percentage by MRI.

PubMed

Müller, Hans-Peter; Raudies, Florian; Unrath, Alexander; Neumann, Heiko; Ludolph, Albert C; Kassubek, Jan

2011-01-01

The MRI-based evaluation of the quantity and regional distribution of adipose tissue is one objective measure in the investigation of obesity. The aim of this article was to report a comprehensive and automatic analytical method for the determination of the volumes of subcutaneous fat tissue (SFT) and visceral fat tissue (VFT) in either the whole human body or selected slices or regions of interest. Using an MRI protocol in an examination position that was convenient for volunteers and patients with severe diseases, 22 healthy subjects were examined. The software platform was able to merge MRI scans of several body regions acquired in separate acquisitions. Through a cascade of image processing steps, SFT and VFT volumes were calculated. Whole-body SFT and VFT distributions, as well as fat distributions of defined body slices, were analysed in detail. Complete three-dimensional datasets were analysed in a reproducible manner with as few operator-dependent interventions as possible. In order to determine the SFT volume, the ARTIS (Adapted Rendering for Tissue Intensity Segmentation) algorithm was introduced. The advantage of the ARTIS algorithm was the delineation of SFT volumes in regions in which standard region grow techniques fail. Using the ARTIS algorithm, an automatic SFT volume detection was feasible. MRI data analysis was able to determine SFT and VFT volume percentages using new analytical strategies. With the techniques described, it was possible to detect changes in SFT and VFT percentages of the whole body and selected regions. The techniques presented in this study are likely to be of use in obesity-related investigations, as well as in the examination of longitudinal changes in weight during various medical conditions. Copyright © 2010 John Wiley & Sons, Ltd.

Technical Note: Method to correlate whole-specimen histopathology of radical prostatectomy with diagnostic MR imaging

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

McGrath, Deirdre M., E-mail: d.mcgrath@sheffield.ac.uk; Lee, Jenny; Foltz, Warren D.

Purpose: Validation of MRI-guided tumor boundary delineation for targeted prostate cancer therapy is achieved via correlation with gold-standard histopathology of radical prostatectomy specimens. Challenges to accurate correlation include matching the pathology sectioning plane with the in vivo imaging slice plane and correction for the deformation that occurs between in vivo imaging and histology. A methodology is presented for matching of the histological sectioning angle and position to the in vivo imaging slices. Methods: Patients (n = 4) with biochemical failure following external beam radiotherapy underwent diagnostic MRI to confirm localized recurrence of prostate cancer, followed by salvage radical prostatectomy. High-resolutionmore » 3-D MRI of the ex vivo specimens was acquired to determine the pathology sectioning angle that best matched the in vivo imaging slice plane, using matching anatomical features and implanted fiducials. A novel sectioning device was developed to guide sectioning at the correct angle, and to assist the insertion of reference dye marks to aid in histopathology reconstruction. Results: The percentage difference in the positioning of the urethra in the ex vivo pathology sections compared to the positioning in in vivo images was reduced from 34% to 7% through slicing at the best match angle. Reference dye marks were generated, which were visible in ex vivo imaging, in the tissue sections before and after processing, and in histology sections. Conclusions: The method achieved an almost fivefold reduction in the slice-matching error and is readily implementable in combination with standard MRI technology. The technique will be employed to generate datasets for correlation of whole-specimen prostate histopathology with in vivo diagnostic MRI using 3-D deformable registration, allowing assessment of the sensitivity and specificity of MRI parameters for prostate cancer. Although developed specifically for prostate, the method is readily adaptable to other types of whole tissue specimen, such as mastectomy or liver resection.« less

A comparative study of software programmes for cross-sectional skeletal muscle and adipose tissue measurements on abdominal computed tomography scans of rectal cancer patients.

PubMed

van Vugt, Jeroen L A; Levolger, Stef; Gharbharan, Arvind; Koek, Marcel; Niessen, Wiro J; Burger, Jacobus W A; Willemsen, Sten P; de Bruin, Ron W F; IJzermans, Jan N M

2017-04-01

The association between body composition (e.g. sarcopenia or visceral obesity) and treatment outcomes, such as survival, using single-slice computed tomography (CT)-based measurements has recently been studied in various patient groups. These studies have been conducted with different software programmes, each with their specific characteristics, of which the inter-observer, intra-observer, and inter-software correlation are unknown. Therefore, a comparative study was performed. Fifty abdominal CT scans were randomly selected from 50 different patients and independently assessed by two observers. Cross-sectional muscle area (CSMA, i.e. rectus abdominis, oblique and transverse abdominal muscles, paraspinal muscles, and the psoas muscle), visceral adipose tissue area (VAT), and subcutaneous adipose tissue area (SAT) were segmented by using standard Hounsfield unit ranges and computed for regions of interest. The inter-software, intra-observer, and inter-observer agreement for CSMA, VAT, and SAT measurements using FatSeg, OsiriX, ImageJ, and sliceOmatic were calculated using intra-class correlation coefficients (ICCs) and Bland-Altman analyses. Cohen's κ was calculated for the agreement of sarcopenia and visceral obesity assessment. The Jaccard similarity coefficient was used to compare the similarity and diversity of measurements. Bland-Altman analyses and ICC indicated that the CSMA, VAT, and SAT measurements between the different software programmes were highly comparable (ICC 0.979-1.000, P < 0.001). All programmes adequately distinguished between the presence or absence of sarcopenia (κ = 0.88-0.96 for one observer and all κ = 1.00 for all comparisons of the other observer) and visceral obesity (all κ = 1.00). Furthermore, excellent intra-observer (ICC 0.999-1.000, P < 0.001) and inter-observer (ICC 0.998-0.999, P < 0.001) agreement for all software programmes were found. Accordingly, excellent Jaccard similarity coefficients were found for all comparisons (mean ≥ 0.964). FatSeg, OsiriX, ImageJ, and sliceOmatic showed an excellent agreement for CSMA, VAT, and SAT measurements on abdominal CT scans. Furthermore, excellent inter-observer and intra-observer agreement were achieved. Therefore, results of studies using these different software programmes can reliably be compared. © 2016 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

A comparative study of software programmes for cross‐sectional skeletal muscle and adipose tissue measurements on abdominal computed tomography scans of rectal cancer patients

PubMed Central

Levolger, Stef; Gharbharan, Arvind; Koek, Marcel; Niessen, Wiro J.; Burger, Jacobus W.A.; Willemsen, Sten P.; de Bruin, Ron W.F.

2016-01-01

Abstract Background The association between body composition (e.g. sarcopenia or visceral obesity) and treatment outcomes, such as survival, using single‐slice computed tomography (CT)‐based measurements has recently been studied in various patient groups. These studies have been conducted with different software programmes, each with their specific characteristics, of which the inter‐observer, intra‐observer, and inter‐software correlation are unknown. Therefore, a comparative study was performed. Methods Fifty abdominal CT scans were randomly selected from 50 different patients and independently assessed by two observers. Cross‐sectional muscle area (CSMA, i.e. rectus abdominis, oblique and transverse abdominal muscles, paraspinal muscles, and the psoas muscle), visceral adipose tissue area (VAT), and subcutaneous adipose tissue area (SAT) were segmented by using standard Hounsfield unit ranges and computed for regions of interest. The inter‐software, intra‐observer, and inter‐observer agreement for CSMA, VAT, and SAT measurements using FatSeg, OsiriX, ImageJ, and sliceOmatic were calculated using intra‐class correlation coefficients (ICCs) and Bland–Altman analyses. Cohen's κ was calculated for the agreement of sarcopenia and visceral obesity assessment. The Jaccard similarity coefficient was used to compare the similarity and diversity of measurements. Results Bland–Altman analyses and ICC indicated that the CSMA, VAT, and SAT measurements between the different software programmes were highly comparable (ICC 0.979–1.000, P < 0.001). All programmes adequately distinguished between the presence or absence of sarcopenia (κ = 0.88–0.96 for one observer and all κ = 1.00 for all comparisons of the other observer) and visceral obesity (all κ = 1.00). Furthermore, excellent intra‐observer (ICC 0.999–1.000, P < 0.001) and inter‐observer (ICC 0.998–0.999, P < 0.001) agreement for all software programmes were found. Accordingly, excellent Jaccard similarity coefficients were found for all comparisons (mean ≥ 0.964). Conclusions FatSeg, OsiriX, ImageJ, and sliceOmatic showed an excellent agreement for CSMA, VAT, and SAT measurements on abdominal CT scans. Furthermore, excellent inter‐observer and intra‐observer agreement were achieved. Therefore, results of studies using these different software programmes can reliably be compared. PMID:27897414

A search for presynaptic inhibitory histamine receptors in guinea-pig tissues: Further H3 receptors but no evidence for H4 receptors.

PubMed

Petri, Doris; Schlicker, Eberhard

2016-07-01

The histamine H4 receptor is coupled to Gi/o proteins and expressed on inflammatory cells and lymphoid tissues; it was suggested that this receptor also occurs in the brain or on peripheral neurones. Since many Gi/o protein-coupled receptors, including the H3 receptor, serve as presynaptic inhibitory receptors, we studied whether the sympathetic neurones supplying four peripheral tissues and the cholinergic neurones in the hippocampus from the guinea-pig are equipped with release-modulating H4 and H3 receptors. For this purpose, we preincubated tissue pieces from the aorta, atrium, renal cortex and vas deferens with (3)H-noradrenaline and hippocampal slices with (3)H-choline and determined the electrically evoked tritium overflow. The stimulation-evoked overflow in the five superfused tissues was inhibited by the muscarinic receptor agonist oxotremorine, which served as a positive control, but not affected by the H4 receptor agonist 4-methylhistamine. The H3 receptor agonist R-α-methylhistamine inhibited noradrenaline release in the peripheral tissues without affecting acetylcholine release in the hippocampal slices. Thioperamide shifted the concentration-response curve of histamine in the aorta and the renal cortex to the right, yielding apparent pA2 values of 8.0 and 8.1, respectively, which are close to its affinity at other H3 receptors but higher by one log unit than its pKi at the H4 receptor of the guinea-pig. In conclusion, histamine H4 receptors could not be identified in five experimental models of the guinea-pig that are suited for the detection of presynaptic inhibitory receptors whereas H3 receptors could be shown in the peripheral tissues but not in the hippocampus. This article is part of the Special Issue entitled 'Histamine Receptors'. Copyright © 2015 Elsevier Ltd. All rights reserved.

Water potential in excised leaf tissue: comparison of a commercial dew point hygrometer and a thermocouple psychrometer on soybean, wheat, and barley.

PubMed

Nelsen, C E; Safir, G R; Hanson, A D

1978-01-01

Leaf water potential (Psi(leaf)) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Psi(leaf) values from the dew point hygrometer were too high. Agreement was improved by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Psi(leaf) values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status.

Radiation phantom with humanoid shape and adjustable thickness

DOEpatents

Lehmann, Joerg [Pleasanton, CA; Levy, Joshua [Salem, NY; Stern, Robin L [Lodi, CA; Siantar, Christine Hartmann [Livermore, CA; Goldberg, Zelanna [Carmichael, CA

2006-12-19

A radiation phantom comprising a body with a general humanoid shape and at least a portion having an adjustable thickness. In one embodiment, the portion with an adjustable thickness comprises at least one tissue-equivalent slice.

[Anatomy of the skull base and the cranial nerves in slice imaging].

PubMed

Bink, A; Berkefeld, J; Zanella, F

2009-07-01

Computed tomography (CT) and magnetic resonance imaging (MRI) are suitable methods for examination of the skull base. Whereas CT is used to evaluate mainly bone destruction e.g. for planning surgical therapy, MRI is used to show pathologies in the soft tissue and bone invasion. High resolution and thin slice thickness are indispensible for both modalities of skull base imaging. Detailed anatomical knowledge is necessary even for correct planning of the examination procedures. This knowledge is a requirement to be able to recognize and interpret pathologies. MRI is the method of choice for examining the cranial nerves. The total path of a cranial nerve can be visualized by choosing different sequences taking into account the tissue surrounding this cranial nerve. This article summarizes examination methods of the skull base in CT and MRI, gives a detailed description of the anatomy and illustrates it with image examples.

Interactive Medical Volume Visualization for Surgical Operations

DTIC Science & Technology

2001-10-25

the preprocessing and processing stages, related medical brain tissues, which are skull, white matter, gray matter and pathology ( tumor ), are segmented ...from 12 or 16 bit data depths. NMR segmentation plays an important role in our work, because, classifying brain tissues from NMR slices requires an...performing segmentation of brain structures. Our segmentation process uses Self Organizing Feature Maps (SOFM) [12]. In SOM, on the contrary to Feedback

Brain tissue water content in patients with idiopathic normal pressure hydrocephalus.

PubMed

Aygok, G; Marmarou, A; Fatouros, P; Young, H

2006-01-01

Relatively little is known regarding the water content of brain tissue in idiopathic normal-pressure hydrocephalus (NPH) patients. The objective of our study was to determine absolute water content non-invasively in hydrocephalic patients, particularly in the anterior and posterior ventricular horns and in the periventricular white matter. Ten patients who were diagnosed and treated for idiopathic NPH in our clinic were selected for study. Magnetic resonance imaging (MRI) techniques were used to obtain anatomical image slices for quantitative brain water measurements. Apparent diffusion coefficient measures were also extracted from regions of interest. To our knowledge, this is the first study to confirm that periventricular lucency seen on MRI represents increased water content in the extracellular space that is markedly elevated prior to shunting.

Na-KATPase activity and intracellular ion concentrations in the lactating guinea pig mammary gland. Studies on Na-K activated adenosine triphosphatase, XXXVI.

PubMed

Vreeswijk, J H; de Pont, J J; Bonting, S L

1975-01-01

The intracellular sodium, potassium and chloride concentrations in slices of lactating guinea pig mammary gland have been determined by chemical analysis and the use of appropriate values for extracellular space. These ion concentrations after 1 hr incubation at 37 degrees C in a Krebs-Ringer bicarbonate solution are 45mM Na+, 138 mM K+ and 44 mM Cl-, which values are in agreement with those found in fresh mammary gland slices. Inhibition of the NaK activated ATPase cation pump system of the tissue by 10(-4)M ouabain, anoxia or cooling to 0 degrees C Causes a gain of Na+ and an equimolar loss of K+ without a significant change in chloride concentration. The effect of cooling (0 degrees C) is reversible by reincubation at 37 degrees C. Water content of the tissue (76.5% of wet weight) and extracellular space (40.5%) do not change under these conditions. The results permit the conclusion that the NaK activated ATPase system is responsible for the maintenance of the intracellular Na+ and K+ concentrations, but do not support the presence of a chloride pump.

Enhancement of drying and rehydration characteristics of okra by ultrasound pre-treatment application

NASA Astrophysics Data System (ADS)

Tüfekçi, Senem; Özkal, Sami Gökhan

2017-07-01

Effect of ultrasound application prior to hot air drying on drying and rehydration kinetics, rehydration ratio and microstructure of okra slices were investigated. For this purpose, the selected parameters are ultrasound pre-treatment time (10, 20 and 30 min), ultrasound amplitude (55 and 100%) and the temperature of drying air (60 and 70 °C). 5 mm thick cylindrical shaped okra slices were used in the experiments. The samples were immersed in water and ultrasonic pre-treatments were done in water with ultrasonic probe connected to an ultrasonic generator with 20 kHz frequency. Pre-treated samples were dried in a tray drier with a 0.3 m/s air velocity. Ultrasound pre-treatment affected the drying rate of the okra slices significantly. Drying time of okra slices was decreased by the application of ultrasound pre-treatment. Modified Page model found to be the most suitable model for describing the drying characteristics of okra slices. Improvements in rehydration properties of the dried samples were observed due to the ultrasound pre-treatment. The influence of the ultrasound pre-treatment on microstructure was clearly observed through scanning electron microscopy images of the dried samples. As the amplitude of ultrasound increased the changes in structure of the okra tissue increased.

The effect of temperature and anoxia of rat-kidney slices on their subsequent respiration

PubMed Central

Rochman, H.; Clark, P. B.; Lathe, G. H.; Parsons, F. M.

1967-01-01

1. Rat-kidney slices were kept, aerobically and anaerobically, at 4°, 20° and 38°, for 0·5–24hr. The oxygen consumption was then measured at 38°. 2. After 6hr. of storage at 4° the rate of oxygen consumption was the same as controls, but after 12 and 24hr. of storage the oxygen consumption fell by 22 and 32% respectively; there was no difference between the slices kept aerobically and anaerobically for periods of 2–24hr. at 4°. 3. Anaerobic storage at 20° for 2hr. did not affect the subsequent rate of oxygen consumption, but after 4 and 6hr. the anaerobically stored tissue showed loss of oxygen consumption. Aerobic storage had no effect for 6hr. 4. There was a marked fall in the capacity to consume oxygen after 0·5hr. at 38° without oxygen. 5. Kidney slices stored at 4° lost nitrogen. The presence of oxygen did not affect this nitrogen loss. PMID:6030298

Imaging human brain cyto- and myelo-architecture with quantitative OCT (Conference Presentation)

NASA Astrophysics Data System (ADS)

Boas, David A.; Wang, Hui; Konukoglu, Ender; Fischl, Bruce; Sakadzic, Sava; Magnain, Caroline V.

2017-02-01

No current imaging technology allows us to directly and without significant distortion visualize the microscopic and defining anatomical features of the human brain. Ex vivo histological techniques can yield exquisite planar images, but the cutting, mounting and staining that are required components of this type of imaging induce distortions that are different for each slice, introducing cross-slice differences that prohibit true 3D analysis. We are overcoming this issue by utilizing Optical Coherence Tomography (OCT) with the goal to image whole human brain cytoarchitectural and laminar properties with potentially 3.5 µm resolution in block-face without the need for exogenous staining. From the intrinsic scattering contrast of the brain tissue, OCT gives us images that are comparable to Nissl stains, but without the distortions introduced in standard histology as the OCT images are acquired from the block face prior to slicing and thus without the need for subsequent staining and mounting. We have shown that laminar and cytoarchitectural properties of the brain can be characterized with OCT just as well as with Nissl staining. We will present our recent advances to improve the axial resolution while maintaining contrast; improvements afforded by speckle reduction procedures; and efforts to obtain quantitative maps of the optical scattering coefficient, an intrinsic property of the tissue.

Computed tomographic anatomy of the equine foot.

PubMed

Claerhoudt, S; Bergman, E H J; Saunders, J H

2014-10-01

This study describes a detailed computed tomographic reference of the normal equine foot. Ten forefeet of five adult cadavers, without evidence of orthopaedic disease, were used. Computed tomography (CT) was performed on all feet. Two-millimetre thick transverse slices were obtained, and sagittal and dorsal planes were reformatted. The CT images were matched with the corresponding anatomic slices. The phalanges and the distal sesamoid bone showed excellent detail. The extensor and flexor tendons (including their attachments) could be clearly evaluated. The collateral (sesamoidean) ligaments could be readily located, but were difficult to delineate at their proximal attachment. The distal digital annular ligament could only be distinguished from the deep digital flexor tendon proximal to the distal sesamoid bone, and its proximal attachment could be identified, but not its distal insertion. Small ligaments (impar ligament, chondrosesamoidean, chondrocoronal and chondrocompedal ligaments, axial and abaxial palmar ligaments of the proximal inter-phalangeal joint) were seen with difficulty and not at all slices. The joint capsules could not be delineated from the surrounding soft tissue structures. The lateral and medial proprius palmar digital artery and vein could be visualized occasionally on some slices. The ungular cartilages, corium and hoof wall layering were seen. The nerves, the articular and fibrocartilage of the distal sesamoid bone and the chondroungular ligament could not be assessed. Computed tomography of the equine foot can be of great value when results of radiography and ultrasonography are inconclusive. Images obtained in this study may serve as reference for CT of the equine foot. © 2013 Blackwell Verlag GmbH.

gamma-Glutamyl amino acids. Transport and conversion to 5-oxoproline in the kidney

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

Bridges, R.J.; Meister, A.

1985-06-25

Transport of gamma-glutamyl amino acids, a step in the proposed glutathione-gamma-glutamyl transpeptidase-mediated amino acid transport pathway, was examined in mouse kidney. The transport of gamma-glutamyl amino acids was demonstrated in vitro in studies on kidney slices. Transport was followed by measuring uptake of /sup 35/S after incubation of the slices in media containing gamma-glutamyl methionine (/sup 35/S)sulfone. The experimental complication associated with extracellular conversion of the gamma-glutamyl amino acid to amino acid and uptake of the latter by slices was overcome by using 5-oxoproline formation (catalyzed by intracellular gamma-glutamyl-cyclotransferase) as an indicator of gamma-glutamyl amino acid transport. This method wasmore » also successfully applied to studies on transport of gamma-glutamyl amino acids in vivo. Transport of gamma-glutamyl amino acids in vitro and in vivo is inhibited by several inhibitors of gamma-glutamyl transpeptidase and also by high extracellular levels of glutathione. This seems to explain urinary excretion of gamma-glutamylcystine by humans with gamma-glutamyl transpeptidase deficiency and by mice treated with inhibitors of this enzyme. Mice depleted of glutathione by treatment with buthionine sulfoximine (which inhibits glutathione synthesis) or by treatment with 2,6-dimethyl-2,5-heptadiene-4-one (which effectively interacts with tissue glutathione) exhibited significantly less transport of gamma-glutamyl amino acids than did untreated controls. The findings suggest that intracellular glutathione functions in transport of gamma-glutamyl amino acids. Evidence was also obtained for transport of gamma-glutamyl gamma-glutamylphenylalanine into kidney slices.« less

Blast waves from detonated military explosive reduce GluR1 and synaptophysin levels in hippocampal slice cultures✩

PubMed Central

Smith, Marquitta; Piehler, Thuvan; Benjamin, Richard; Farizatto, Karen L.; Pait, Morgan C.; Almeida, Michael F.; Ghukasyan, Vladimir V.; Bahr, Ben A.

2017-01-01

Explosives create shockwaves that cause blast-induced neurotrauma, one of the most common types of traumatic brain injury (TBI) linked to military service. Blast-induced TBIs are often associated with reduced cognitive and behavioral functions due to a variety of factors. To study the direct effects of military explosive blasts on brain tissue, we removed systemic factors by utilizing rat hippocampal slice cultures. The long-term slice cultures were briefly sealed air-tight in serum-free medium, lowered into a 37 °C water-filled tank, and small 1.7-gram assemblies of cyclotrimethylene trinitramine (RDX) were detonated 15 cm outside the tank, creating a distinct shockwave recorded at the culture plate position. Compared to control mock-treated groups of slices that received equal submerge time, 1–3 blast impacts caused a dose-dependent reduction in the AMPA receptor subunit GluR1. While only a small reduction was found in hippocampal slices exposed to a single RDX blast and harvested 1–2 days later, slices that received two consecutive RDX blasts 4 min apart exhibited a 26–40% reduction in GluR1, and the receptor subunit was further reduced by 64–72% after three consecutive blasts. Such loss correlated with increased levels of HDAC2, a histone deacetylase implicated in stress-induced reduction of glutamatergic transmission. No evidence of synaptic marker recovery was found at 72 h post-blast. The presynaptic marker synaptophysin was found to have similar susceptibility as GluR1 to the multiple explosive detonations. In contrast to the synaptic protein reductions, actin levels were unchanged, spectrin breakdown was not detected, and Fluoro-Jade B staining found no indication of degenerating neurons in slices exposed to three RDX blasts, suggesting that small, sub-lethal explosives are capable of producing selective alterations to synaptic integrity. Together, these results indicate that blast waves from military explosive cause signs of synaptic compromise without producing severe neurodegeneration, perhaps explaining the cognitive and behavioral changes in those blast-induced TBI sufferers that have no detectable neuropathology. PMID:27720798

Fascial structures and autonomic nerves in the female pelvis: a study using macroscopic slices and their corresponding histology.

PubMed

Tamakawa, Mitsuharu; Murakami, Gen; Takashima, Ken; Kato, Tomoyasu; Hareyama, Masato

2003-12-01

We investigated the topographical anatomy of the pelvic fasciae and autonomic nerves using macroscopic slices of five decalcified female pelves. The lateral aspect of the supravaginal cervix uteri and superior-most vagina issued abundant thick fiber bundles. These visceral fibrous tissues extended dorsolaterally, joined another fibrous tissue from the rectum (the actual lateral ligament of the rectum) and attached to the parietal fibrous tissues at and around the sciatic foramina (i.e. the sacrospinous ligament, thick fasciae of the coccygeus and piriformis and dorsal end of the covering fascia of the levator ani). The inferior or ventral vagina also issued thick fiber bundles communicating with the levator ani fascia. This connection between the vagina and levator fascia, when stretched, seemed to provide a macroscopic morphology called the arcus tendineus fasciae pelvis. The overall morphology of the visceroparietal fascial bridge exhibited a bilateral wing-like shape. The fascial bridge complex was adjacent but dorso-inferior to the internal iliac vascular sheath and located slightly ventral to the pelvic splanchnic nerve. However, the pelvic plexus and its peripheral branches were embedded in the fascial complex. The hypogastric nerve ran along and beneath the uterosacral peritoneal fold, which did not contain thick fibrous tissue. During surgery, in combination with the superficially located vascular sheath, the morphology of the visceroparietal fascial bridge and associated nerves seemed to be artificially changed and developed into the so-called cardinal, uterosacral, uterovesical and/or rectal lateral ligaments. The classical and original concepts of these pelvic fascial structures may need to be altered to adjust to these surgical observations.

Diffusion weighted whole body imaging with background body signal suppression (DWIBS): technical improvement using free breathing, STIR and high resolution 3D display.

PubMed

Takahara, Taro; Imai, Yutaka; Yamashita, Tomohiro; Yasuda, Seiei; Nasu, Seiji; Van Cauteren, Marc

2004-01-01

To examine a new way of body diffusion weighted imaging (DWI) using the short TI inversion recovery-echo planar imaging (STIR-EPI) sequence and free breathing scanning (diffusion weighted whole body imaging with background body signal suppression; DWIBS) to obtain three-dimensional displays. 1) Apparent contrast-to-noise ratios (AppCNR) between lymph nodes and surrounding fat tissue were compared in three types of DWI with and without breath-holding, with variable lengths of scan time and slice thickness. 2) The STIR-EPI sequence and spin echo-echo planar imaging (SE-EPI) sequence with chemical shift selective (CHESS) pulse were compared in terms of their degree of fat suppression. 3) Eleven patients with neck, chest, and abdominal malignancy were scanned with DWIBS for evaluation of feasibility. Whole body imaging was done in a later stage of the study using the peripheral vascular coil. The AppCNR of 8 mm slice thickness images reconstructed from 4 mm slice thickness source images obtained in a free breathing scan of 430 sec were much better than 9 mm slice thickness breath-hold scans obtained in 25 sec. High resolution multi-planar reformat (MPR) and maximum intensity projection (MIP) images could be made from the data set of 4 mm slice thickness images. Fat suppression was much better in the STIR-EPI sequence than SE-EPI with CHESS pulse. The feasibility of DWIBS was showed in clinical scans of 11 patients. Whole body images were successfully obtained with adequate fat suppression. Three-dimensional DWIBS can be obtained with this technique, which may allow us to screen for malignancies in the whole body.

Identification and quantitative evaluation of the fiber structure in the pathological tissue using Mueller matrix microscope

NASA Astrophysics Data System (ADS)

Zhou, Jialing; He, Honghui; Wang, Ye; Ma, Hui

2017-02-01

Fiber structure changes in the various pathological processes, such as the increase of fibrosis in liver diseases, the derangement of fiber in cervical cancer and so on. Currently, clinical pathologic diagnosis is regarded as the golden criterion, but different doctors with discrepancy in knowledge and experience may obtain different conclusions. Up to a point, quantitative evaluation of the fiber structure in the pathological tissue can be of great service to quantitative diagnosis. Mueller matrix measurement is capable of probing comprehensive microstructural information of samples and different wavelength of lights can provide more information. In this paper, we use a Mueller matrix microscope with light sources in six different wavelength. We use unstained, dewaxing liver tissue slices in four stages and the pathological biopsy of the filtration channels from rabbit eyes as samples. We apply the Mueller matrix polar decomposition (MMPD) parameter δ which corresponds to retardance to liver slices. The mean value of abnormal region get bigger when the level of fibrosis get higher and light in short wavelength is more sensitive to the microstructure of fiber. On the other hand, we use the Mueller matrix transformation (MMT) parameter Φ which is associated to the angel of fast axis in the analysis of the slices of the filtration channels from rabbit eyes. The value of kurtosis and the value of skewness shows big difference between new born region and normal region and can reveal the arrangement of fiber. These results indicate that the Mueller matrix microscope has great potential in auxiliary diagnosis.

Adipose tissue MRI for quantitative measurement of central obesity.

PubMed

Poonawalla, Aziz H; Sjoberg, Brett P; Rehm, Jennifer L; Hernando, Diego; Hines, Catherine D; Irarrazaval, Pablo; Reeder, Scott B

2013-03-01

To validate adipose tissue magnetic resonance imaging (atMRI) for rapid, quantitative volumetry of visceral adipose tissue (VAT) and total adipose tissue (TAT). Data were acquired on normal adults and clinically overweight girls with Institutional Review Board (IRB) approval/parental consent using sagittal 6-echo 3D-spoiled gradient-echo (SPGR) (26-sec single-breath-hold) at 3T. Fat-fraction images were reconstructed with quantitative corrections, permitting measurement of a physiologically based fat-fraction threshold in normals to identify adipose tissue, for automated measurement of TAT, and semiautomated measurement of VAT. TAT accuracy was validated using oil phantoms and in vivo TAT/VAT measurements validated with manual segmentation. Group comparisons were performed between normals and overweight girls using TAT, VAT, VAT-TAT-ratio (VTR), body-mass-index (BMI), waist circumference, and waist-hip-ratio (WHR). Oil phantom measurements were highly accurate (<3% error). The measured adipose fat-fraction threshold was 96% ± 2%. VAT and TAT correlated strongly with manual segmentation (normals r(2) ≥ 0.96, overweight girls r(2) ≥ 0.99). VAT segmentation required 30 ± 11 minutes/subject (14 ± 5 sec/slice) using atMRI, versus 216 ± 73 minutes/subject (99 ± 31 sec/slice) manually. Group discrimination was significant using WHR (P < 0.001) and VTR (P = 0.004). The atMRI technique permits rapid, accurate measurements of TAT, VAT, and VTR. Copyright © 2012 Wiley Periodicals, Inc.

Intracellular ATP influences synaptic plasticity in area CA1 of rat hippocampus via metabolism to adenosine and activity-dependent activation of adenosine A1 receptors.

PubMed

zur Nedden, Stephanie; Hawley, Simon; Pentland, Naomi; Hardie, D Grahame; Doney, Alexander S; Frenguelli, Bruno G

2011-04-20

The extent to which brain slices reflect the energetic status of the in vivo brain has been a subject of debate. We addressed this issue to investigate the recovery of energetic parameters and adenine nucleotides in rat hippocampal slices and the influence this has on synaptic transmission and plasticity. We show that, although adenine nucleotide levels recover appreciably within 10 min of incubation, it takes 3 h for a full recovery of the energy charge (to ≥ 0.93) and that incubation of brain slices at 34°C results in a significantly higher ATP/AMP ratio and a threefold lower activity of AMP-activated protein kinase compared with slices incubated at room temperature. Supplementation of artificial CSF with d-ribose and adenine (Rib/Ade) increased the total adenine nucleotide pool of brain slices, which, when corrected for the influence of the dead cut edges, closely approached in vivo values. Rib/Ade did not affect basal synaptic transmission or paired-pulse facilitation but did inhibit long-term potentiation (LTP) induced by tetanic or weak theta-burst stimulation. This decrease in LTP was reversed by strong theta-burst stimulation or antagonizing the inhibitory adenosine A(1) receptor suggesting that the elevated tissue ATP levels had resulted in greater activity-dependent adenosine release during LTP induction. This was confirmed by direct measurement of adenosine release with adenosine biosensors. These observations provide new insight into the recovery of adenine nucleotides after slice preparation, the sources of loss of such compounds in brain slices, the means by which to restore them, and the functional consequences of doing so.

Wear biomechanics in the slicing dentition of the giant horned dinosaur Triceratops

PubMed Central

Erickson, Gregory M.; Sidebottom, Mark A.; Kay, David I.; Turner, Kevin T.; Ip, Nathan; Norell, Mark A.; Sawyer, W. Gregory; Krick, Brandon A.

2015-01-01

Herbivorous reptiles rarely evolve occluding dentitions that allow for the mastication (chewing) of plant matter. Conversely, most herbivorous mammals have occluding teeth with complex tissue architectures that self-wear to complex morphologies for orally processing plants. Dinosaurs stand out among reptiles in that several lineages acquired the capacity to masticate. In particular, the horned ceratopsian dinosaurs, among the most successful Late Cretaceous dinosaurian lineages, evolved slicing dentitions for the exploitation of tough, bulky plant matter. We show how Triceratops, a 9-m-long ceratopsian, and its relatives evolved teeth that wore during feeding to create fullers (recessed central regions on cutting blades) on the chewing surfaces. This unique morphology served to reduce friction during feeding. It was achieved through the evolution of a complex suite of osseous dental tissues rivaling the complexity of mammalian dentitions. Tribological (wear) properties of the tissues are preserved in ~66-million-year-old teeth, allowing the creation of a sophisticated three-dimensional biomechanical wear model that reveals how the complexes synergistically wore to create these implements. These findings, along with similar discoveries in hadrosaurids (duck-billed dinosaurs), suggest that tissue-mediated changes in dental morphology may have played a major role in the remarkable ecological diversification of these clades and perhaps other dinosaurian clades capable of mastication. PMID:26601198

Shock Wave Treatment Protects From Neuronal Degeneration via a Toll-Like Receptor 3 Dependent Mechanism: Implications of a First-Ever Causal Treatment for Ischemic Spinal Cord Injury.

PubMed

Lobenwein, Daniela; Tepeköylü, Can; Kozaryn, Radoslaw; Pechriggl, Elisabeth J; Bitsche, Mario; Graber, Michael; Fritsch, Helga; Semsroth, Severin; Stefanova, Nadia; Paulus, Patrick; Czerny, Martin; Grimm, Michael; Holfeld, Johannes

2015-10-27

Paraplegia following spinal cord ischemia represents a devastating complication of both aortic surgery and endovascular aortic repair. Shock wave treatment was shown to induce angiogenesis and regeneration in ischemic tissue by modulation of early inflammatory response via Toll-like receptor (TLR) 3 signaling. In preclinical and clinical studies, shock wave treatment had a favorable effect on ischemic myocardium. We hypothesized that shock wave treatment also may have a beneficial effect on spinal cord ischemia. A spinal cord ischemia model in mice and spinal slice cultures ex vivo were performed. Treatment groups received immediate shock wave therapy, which resulted in decreased neuronal degeneration and improved motor function. In spinal slice cultures, the activation of TLR3 could be observed. Shock wave effects were abolished in spinal slice cultures from TLR3(-/-) mice, whereas the effect was still present in TLR4(-/-) mice. TLR4 protein was found to be downregulated parallel to TLR3 signaling. Shock wave-treated animals showed significantly better functional outcome and survival. The protective effect on neurons could be reproduced in human spinal slices. Shock wave treatment protects from neuronal degeneration via TLR3 signaling and subsequent TLR4 downregulation. Consequently, it represents a promising treatment option for the devastating complication of spinal cord ischemia after aortic repair. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Analysis of lipid raft molecules in the living brain slices.

PubMed

Kotani, Norihiro; Nakano, Takanari; Ida, Yui; Ito, Rina; Hashizume, Miki; Yamaguchi, Arisa; Seo, Makoto; Araki, Tomoyuki; Hojo, Yasushi; Honke, Koichi; Murakoshi, Takayuki

2017-08-24

Neuronal plasma membrane has been thought to retain a lot of lipid raft components which play important roles in the neural function. Although the biochemical analyses of lipid raft using brain tissues have been extensively carried out in the past 20 years, many of their experimental conditions do not coincide with those of standard neuroscience researches such as neurophysiology and neuropharmacology. Hence, the physiological methods for lipid raft analysis that can be compatible with general neuroscience have been required. Herein, we developed a system to physiologically analyze ganglioside GM1-enriched lipid rafts in brain tissues using the "Enzyme-Mediated Activation of Radical Sources (EMARS)" method that we reported (Kotani N. et al. Proc. Natl. Acad. Sci. U S A 105, 7405-7409 (2008)). The EMARS method was applied to acute brain slices prepared from mouse brains in aCSF solution using the EMARS probe, HRP-conjugated cholera toxin subunit B, which recognizes ganglioside GM1. The membrane molecules present in the GM1-enriched lipid rafts were then labeled with fluorescein under the physiological condition. The fluorescein-tagged lipid raft molecules called "EMARS products" distributed differentially among various parts of the brain. On the other hand, appreciable differences were not detected among segments along the longitudinal axis of the hippocampus. We further developed a device to label the lipid raft molecules in acute hippocampal slices under two different physiological conditions to detect dynamics of the lipid raft molecules during neural excitation. Using this device, several cell membrane molecules including Thy1, known as a lipid raft resident molecule in neurons, were confirmed by the EMARS method in living hippocampal slices. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Preparation of simulate craniocerebral models via three dimensional printing technique].

PubMed

Lan, Q; Chen, A L; Zhang, T; Zhu, Q; Xu, T

2016-08-09

Three dimensional (3D) printing technique was used to prepare the simulate craniocerebral models, which were applied to preoperative planning and surgical simulation. The image data was collected from PACS system. Image data of skull bone, brain tissue and tumors, cerebral arteries and aneurysms, and functional regions and relative neural tracts of the brain were extracted from thin slice scan (slice thickness 0.5 mm) of computed tomography (CT), magnetic resonance imaging (MRI, slice thickness 1mm), computed tomography angiography (CTA), and functional magnetic resonance imaging (fMRI) data, respectively. MIMICS software was applied to reconstruct colored virtual models by identifying and differentiating tissues according to their gray scales. Then the colored virtual models were submitted to 3D printer which produced life-sized craniocerebral models for surgical planning and surgical simulation. 3D printing craniocerebral models allowed neurosurgeons to perform complex procedures in specific clinical cases though detailed surgical planning. It offered great convenience for evaluating the size of spatial fissure of sellar region before surgery, which helped to optimize surgical approach planning. These 3D models also provided detailed information about the location of aneurysms and their parent arteries, which helped surgeons to choose appropriate aneurismal clips, as well as perform surgical simulation. The models further gave clear indications of depth and extent of tumors and their relationship to eloquent cortical areas and adjacent neural tracts, which were able to avoid surgical damaging of important neural structures. As a novel and promising technique, the application of 3D printing craniocerebral models could improve the surgical planning by converting virtual visualization into real life-sized models.It also contributes to functional anatomy study.

Multiphoton microscopy guides neurotrophin modification with poly(ethylene glycol) to enhance interstitial diffusion

NASA Astrophysics Data System (ADS)

Stroh, Mark; Zipfel, Warren R.; Williams, Rebecca M.; Ma, Shu Chin; Webb, Watt W.; Saltzman, W. Mark

2004-07-01

Brain-derived neurotrophic factor (BDNF) is a promising therapeutic agent for the treatment of neurodegenerative diseases. However, the limited distribution of this molecule after administration into the brain tissue considerably hampers its efficacy. Here, we show how multiphoton microscopy of fluorescently tagged BDNF in brain-tissue slices provides a useful and rapid screening method for examining the diffusion of large molecules in tissues, and for studying the effects of chemical modifications-for example, conjugating with polyethylene glycol (PEG)-on the diffusion constant. This single variable, obtained by monitoring short-term diffusion in real time, can be effectively used for rational drug design. In this study on fluorescently tagged BDNF and BDNF-PEG, we identify slow diffusion as a major contributing factor to the limited penetration of BDNF, and demonstrate how chemical modification can be used to overcome this barrier.

Determination of tissue equivalent materials of a physical 8-year-old phantom for use in computed tomography

NASA Astrophysics Data System (ADS)

Akhlaghi, Parisa; Miri Hakimabad, Hashem; Rafat Motavalli, Laleh

2015-07-01

This paper reports on the methodology applied to select suitable tissue equivalent materials of an 8-year phantom for use in computed tomography (CT) examinations. To find the appropriate tissue substitutes, first physical properties (physical density, electronic density, effective atomic number, mass attenuation coefficient and CT number) of different materials were studied. Results showed that, the physical properties of water and polyurethane (as soft tissue), B-100 and polyvinyl chloride (PVC) (as bone) and polyurethane foam (as lung) agree more with those of original tissues. Then in the next step, the absorbed doses in the location of 25 thermoluminescent dosimeters (TLDs) as well as dose distribution in one slice of phantom were calculated for original and these proposed materials by Monte Carlo simulation at different tube voltages. The comparisons suggested that at tube voltages of 80 and 100 kVp using B-100 as bone, water as soft tissue and polyurethane foam as lung is suitable for dosimetric study in pediatric CT examinations. In addition, it was concluded that by considering just the mass attenuation coefficient of different materials, the appropriate tissue equivalent substitutes in each desired X-ray energy range could be found.

The relationship between decorrelation time and sample thickness in acute rat brain tissue slices (Conference Presentation)

NASA Astrophysics Data System (ADS)

Brake, Joshua; Jang, Mooseok; Yang, Changhuei

2016-03-01

The optical opacity of biological tissue has long been a challenge in biomedical optics due to the strong scattering nature of tissue in the optical regime. While most conventional optical techniques attempt to gate out multiply scattered light and use only unscattered light, new approaches in the field of wavefront shaping exploit the time reversible symmetry of optical scattering in order to focus light inside or through scattering media. While these approaches have been demonstrated effectively on static samples, it has proven difficult to apply them to dynamic biological samples since even small changes in the relative positions of the scatterers within will cause the time symmetry that wavefront shaping relies upon to decorrelate. In this paper we investigate the decorrelation curves of acute rat brain slices for thicknesses in the range 1-3 mm (1/e decorrelation time on the order of seconds) using multi-speckle diffusing wave spectroscopy (MSDWS) and compare the results with theoretical predictions. The results of this study demonstrate that the 1/L^2 relationship between decorrelation time and thickness predicted by diffusing wave spectroscopy provides a good rule of thumb for estimating how the decorrelation of a sample will change with increasing thickness. Understanding this relationship will provide insight to guide the future development of biophotonic wavefront shaping tools by giving an estimate of how fast wavefront shaping systems need to operate to overcome the dynamic nature of biological samples.

Circadian Timing in the Lung; A Specific Role for Bronchiolar Epithelial Cells

PubMed Central

Gibbs, J. E.; Beesley, S.; Plumb, J.; Singh, D.; Farrow, S.; Ray, D. W.; Loudon, A. S. I.

2015-01-01

In addition to the core circadian oscillator, located within the suprachiasmatic nucleus, numerous peripheral tissues possess self-sustaining circadian timers. In vivo these are entrained and temporally synchronized by signals conveyed from the core oscillator. In the present study, we examine circadian timing in the lung, determine the cellular localization of core clock proteins in both mouse and human lung tissue, and establish the effects of glucocorticoids (widely used in the treatment of asthma) on the pulmonary clock. Using organotypic lung slices prepared from transgenic mPER2::Luc mice, luciferase levels, which report PER2 expression, were measured over a number of days. We demonstrate a robust circadian rhythm in the mouse lung that is responsive to glucocorticoids. Immunohistochemical techniques were used to localize specific expression of core clock proteins, and the glucocorticoid receptor, to the epithelial cells lining the bronchioles in both mouse and human lung. In the mouse, these were established to be Clara cells. Murine Clara cells retained circadian rhythmicity when grown as a pure population in culture. Furthermore, selective ablation of Clara cells resulted in the loss of circadian rhythm in lung slices, demonstrating the importance of this cell type in maintaining overall pulmonary circadian rhythmicity. In summary, we demonstrate that Clara cells are critical for maintaining coherent circadian oscillations in lung tissue. Their coexpression of the glucocorticoid receptor and core clock components establishes them as a likely interface between humoral suprachiasmatic nucleus output and circadian lung physiology. PMID:18787022

Quantitative comparison and evaluation of software packages for assessment of abdominal adipose tissue distribution by magnetic resonance imaging.

PubMed

Bonekamp, S; Ghosh, P; Crawford, S; Solga, S F; Horska, A; Brancati, F L; Diehl, A M; Smith, S; Clark, J M

2008-01-01

To examine five available software packages for the assessment of abdominal adipose tissue with magnetic resonance imaging, compare their features and assess the reliability of measurement results. Feature evaluation and test-retest reliability of softwares (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision) used in manual, semi-automated or automated segmentation of abdominal adipose tissue. A random sample of 15 obese adults with type 2 diabetes. Axial T1-weighted spin echo images centered at vertebral bodies of L2-L3 were acquired at 1.5 T. Five software packages were evaluated (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision), comparing manual, semi-automated and automated segmentation approaches. Images were segmented into cross-sectional area (CSA), and the areas of visceral (VAT) and subcutaneous adipose tissue (SAT). Ease of learning and use and the design of the graphical user interface (GUI) were rated. Intra-observer accuracy and agreement between the software packages were calculated using intra-class correlation. Intra-class correlation coefficient was used to obtain test-retest reliability. Three of the five evaluated programs offered a semi-automated technique to segment the images based on histogram values or a user-defined threshold. One software package allowed manual delineation only. One fully automated program demonstrated the drawbacks of uncritical automated processing. The semi-automated approaches reduced variability and measurement error, and improved reproducibility. There was no significant difference in the intra-observer agreement in SAT and CSA. The VAT measurements showed significantly lower test-retest reliability. There were some differences between the software packages in qualitative aspects, such as user friendliness. Four out of five packages provided essentially the same results with respect to the inter- and intra-rater reproducibility. Our results using SliceOmatic, Analyze or NIHImage were comparable and could be used interchangeably. Newly developed fully automated approaches should be compared to one of the examined software packages.

Quantitative comparison and evaluation of software packages for assessment of abdominal adipose tissue distribution by magnetic resonance imaging

PubMed Central

Bonekamp, S; Ghosh, P; Crawford, S; Solga, SF; Horska, A; Brancati, FL; Diehl, AM; Smith, S; Clark, JM

2009-01-01

Objective To examine five available software packages for the assessment of abdominal adipose tissue with magnetic resonance imaging, compare their features and assess the reliability of measurement results. Design Feature evaluation and test–retest reliability of softwares (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision) used in manual, semi-automated or automated segmentation of abdominal adipose tissue. Subjects A random sample of 15 obese adults with type 2 diabetes. Measurements Axial T1-weighted spin echo images centered at vertebral bodies of L2–L3 were acquired at 1.5 T. Five software packages were evaluated (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision), comparing manual, semi-automated and automated segmentation approaches. Images were segmented into cross-sectional area (CSA), and the areas of visceral (VAT) and subcutaneous adipose tissue (SAT). Ease of learning and use and the design of the graphical user interface (GUI) were rated. Intra-observer accuracy and agreement between the software packages were calculated using intra-class correlation. Intra-class correlation coefficient was used to obtain test–retest reliability. Results Three of the five evaluated programs offered a semi-automated technique to segment the images based on histogram values or a user-defined threshold. One software package allowed manual delineation only. One fully automated program demonstrated the drawbacks of uncritical automated processing. The semi-automated approaches reduced variability and measurement error, and improved reproducibility. There was no significant difference in the intra-observer agreement in SAT and CSA. The VAT measurements showed significantly lower test–retest reliability. There were some differences between the software packages in qualitative aspects, such as user friendliness. Conclusion Four out of five packages provided essentially the same results with respect to the inter- and intra-rater reproducibility. Our results using SliceOmatic, Analyze or NIHImage were comparable and could be used interchangeably. Newly developed fully automated approaches should be compared to one of the examined software packages. PMID:17700582

Rapid Parametric Mapping of the Longitudinal Relaxation Time T1 Using Two-Dimensional Variable Flip Angle Magnetic Resonance Imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla

PubMed Central

Dieringer, Matthias A.; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I.; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

2014-01-01

Introduction Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. Methods T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Results Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Conclusion Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and brain tissue characterization. PMID:24621588

Rapid parametric mapping of the longitudinal relaxation time T1 using two-dimensional variable flip angle magnetic resonance imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla.

PubMed

Dieringer, Matthias A; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

2014-01-01

Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and brain tissue characterization.

Principles, Techniques, and Applications of Tissue Microfluidics

NASA Technical Reports Server (NTRS)

Wade, Lawrence A.; Kartalov, Emil P.; Shibata, Darryl; Taylor, Clive

2011-01-01

The principle of tissue microfluidics and its resultant techniques has been applied to cell analysis. Building microfluidics to suit a particular tissue sample would allow the rapid, reliable, inexpensive, highly parallelized, selective extraction of chosen regions of tissue for purposes of further biochemical analysis. Furthermore, the applicability of the techniques ranges beyond the described pathology application. For example, they would also allow the posing and successful answering of new sets of questions in many areas of fundamental research. The proposed integration of microfluidic techniques and tissue slice samples is called tissue microfluidics because it molds the microfluidic architectures in accordance with each particular structure of each specific tissue sample. Thus, microfluidics can be built around the tissues, following the tissue structure, or alternatively, the microfluidics can be adapted to the specific geometry of particular tissues. By contrast, the traditional approach is that microfluidic devices are structured in accordance with engineering considerations, while the biological components in applied devices are forced to comply with these engineering presets. The proposed principles represent a paradigm shift in microfluidic technology in three important ways: Microfluidic devices are to be directly integrated with, onto, or around tissue samples, in contrast to the conventional method of off-chip sample extraction followed by sample insertion in microfluidic devices. Architectural and operational principles of microfluidic devices are to be subordinated to suit specific tissue structure and needs, in contrast to the conventional method of building devices according to fluidic function alone and without regard to tissue structure. Sample acquisition from tissue is to be performed on-chip and is to be integrated with the diagnostic measurement within the same device, in contrast to the conventional method of off-chip sample prep and subsequent insertion into a diagnostic device. A more advanced form of tissue integration with microfluidics is tissue encapsulation, wherein the sample is completely encapsulated within a microfluidic device, to allow for full surface access. The immediate applications of these approaches lie with diagnostics of tissue slices and biopsy samples e.g. for cancer but the approaches would also be very useful in comparative genomics and other areas of fundamental research involving heterogeneous tissue samples.

Hyperpolarized 13C MR Markers of Renal Tumor Aggressiveness

DTIC Science & Technology

2014-10-01

as a biomarker of tumor aggressiveness in a MR compatible 3D cell and tissue culture bioreactor ” to be presented at the ISMRM Workshop on Magnetic... Cell Carcinoma, Hyperpolarized 13C MR, Sub-renal capsule, patient derived tissue slice cultures , bioreactor 3. OVERALL PROJECT SUMMARY: Aim...grade from high grade RCCs using human TSCs cultured in a bioreactor . Aim 2:Identify HP 13C metabolic markers that discriminate low grade from

Brain Volume Estimation Enhancement by Morphological Image Processing Tools.

PubMed

Zeinali, R; Keshtkar, A; Zamani, A; Gharehaghaji, N

2017-12-01

Volume estimation of brain is important for many neurological applications. It is necessary in measuring brain growth and changes in brain in normal/abnormal patients. Thus, accurate brain volume measurement is very important. Magnetic resonance imaging (MRI) is the method of choice for volume quantification due to excellent levels of image resolution and between-tissue contrast. Stereology method is a good method for estimating volume but it requires to segment enough MRI slices and have a good resolution. In this study, it is desired to enhance stereology method for volume estimation of brain using less MRI slices with less resolution. In this study, a program for calculating volume using stereology method has been introduced. After morphologic method, dilation was applied and the stereology method enhanced. For the evaluation of this method, we used T1-wighted MR images from digital phantom in BrainWeb which had ground truth. The volume of 20 normal brain extracted from BrainWeb, was calculated. The volumes of white matter, gray matter and cerebrospinal fluid with given dimension were estimated correctly. Volume calculation from Stereology method in different cases was made. In three cases, Root Mean Square Error (RMSE) was measured. Case I with T=5, d=5, Case II with T=10, D=10 and Case III with T=20, d=20 (T=slice thickness, d=resolution as stereology parameters). By comparing these results of two methods, it is obvious that RMSE values for our proposed method are smaller than Stereology method. Using morphological operation, dilation allows to enhance the estimation volume method, Stereology. In the case with less MRI slices and less test points, this method works much better compared to Stereology method.

An MR-based Model for Cardio-Respiratory Motion Compensation of Overlays in X-Ray Fluoroscopy

PubMed Central

Fischer, Peter; Faranesh, Anthony; Pohl, Thomas; Maier, Andreas; Rogers, Toby; Ratnayaka, Kanishka; Lederman, Robert; Hornegger, Joachim

2017-01-01

In X-ray fluoroscopy, static overlays are used to visualize soft tissue. We propose a system for cardiac and respiratory motion compensation of these overlays. It consists of a 3-D motion model created from real-time MR imaging. Multiple sagittal slices are acquired and retrospectively stacked to consistent 3-D volumes. Slice stacking considers cardiac information derived from the ECG and respiratory information extracted from the images. Additionally, temporal smoothness of the stacking is enhanced. Motion is estimated from the MR volumes using deformable 3-D/3-D registration. The motion model itself is a linear direct correspondence model using the same surrogate signals as slice stacking. In X-ray fluoroscopy, only the surrogate signals need to be extracted to apply the motion model and animate the overlay in real time. For evaluation, points are manually annotated in oblique MR slices and in contrast-enhanced X-ray images. The 2-D Euclidean distance of these points is reduced from 3.85 mm to 2.75 mm in MR and from 3.0 mm to 1.8 mm in X-ray compared to the static baseline. Furthermore, the motion-compensated overlays are shown qualitatively as images and videos. PMID:28692969

Water potential in excised leaf tissue. Comparison of a commercial dew point hygrometer and a thermocouple psychrometer on soybean, wheat, and barley

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

Nelsen, C.E.; Safir, G.R.; Hanson, A.D.

1978-01-01

Leaf water potential (Psi/sub leaf/) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Psi/sub leaf/ values from the dew point hygrometer were too high. Agreement was improvedmore » by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Psi/sub leaf/ values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status.« less

Improved cerebral energetics and ketone body metabolism in db/db mice

PubMed Central

Andersen, Jens V; Christensen, Sofie K; Nissen, Jakob D

2016-01-01

It is becoming evident that type 2 diabetes mellitus is affecting brain energy metabolism. The importance of alternative substrates for the brain in type 2 diabetes mellitus is poorly understood. The aim of this study was to investigate whether ketone bodies are relevant candidates to compensate for cerebral glucose hypometabolism and unravel the functionality of cerebral mitochondria in type 2 diabetes mellitus. Acutely isolated cerebral cortical and hippocampal slices of db/db mice were incubated in media containing [U-13C]glucose, [1,2-13C]acetate or [U-13C]β-hydroxybutyrate and tissue extracts were analysed by mass spectrometry. Oxygen consumption and ATP synthesis of brain mitochondria of db/db mice were assessed by Seahorse XFe96 and luciferin-luciferase assay, respectively. Glucose hypometabolism was observed for both cerebral cortical and hippocampal slices of db/db mice. Significant increased metabolism of [1,2-13C]acetate and [U-13C]β-hydroxybutyrate was observed for hippocampal slices of db/db mice. Furthermore, brain mitochondria of db/db mice exhibited elevated oxygen consumption and ATP synthesis rate. This study provides evidence of several changes in brain energy metabolism in type 2 diabetes mellitus. The increased hippocampal ketone body utilization and improved mitochondrial function in db/db mice, may act as adaptive mechanisms in order to maintain cerebral energetics during hampered glucose metabolism. PMID:28058963

Nonlocal correlations of polarization-entangled photons through brain tissue (Conference Presentation)

NASA Astrophysics Data System (ADS)

Galvez, Enrique J.; Shi, Lingyan; Alfano, Robert R.

2017-02-01

We investigated the preservation of non-local correlations between polarization-entangled photons when one of them traveled through brain tissue slices of different thicknesses. Using down-converted photons at a wavelength of 802 nm minimized the absorption by the tissue. After the light passed through the tissue samples, we performed quantum state tomography to obtain quantitative measures of the entanglement. We found that entanglement is preserved to a surprising degree, and when it degrades, it does so following a particular path in a tangle versus linear-entropy graph. Such a trajectory reveals direct transfer of probability from entangled to mixed state.

Physiology and quality of fresh-cut produce in CA/MA storage

USDA-ARS?s Scientific Manuscript database

Fresh-cut fruits and vegetables have exposed injured tissues due to the mechanical processes of peeling, slicing and/or cutting. Such processing consequently renders the produce highly susceptible to physiological breakdown and microbial spoilage. Product deterioration is usually accompanied with ph...

Properties of voltage-activated Na+ and K+ currents in mouse hippocampal glial cells in situ and after acute isolation from tissue slices.

PubMed

Steinhäuser, C; Kressin, K; Kuprijanova, E; Weber, M; Seifert, G

1994-10-01

In the present study, we were interested in a quantitative analysis of voltage-activated channels in a subpopulation of hippocampal glial cells, termed "complex" cells. The patch-clamp technique in the whole-cell mode was applied to identified cells in situ and to glial cells acutely isolated from tissue slices. The outward current was composed of two components: a sustained and a transient current. The transient K+ channel had electrophysiological and pharmacological properties resembling those of the channel through which the A-currents pass. In addition, this glial A-type current possessed a significant Ca2+ dependence. The current parameters determined in situ or in isolated cells corresponded well. Due to space clamp problems in situ, properties of voltage-dependent Na+ currents were only analysed in suspended glial cells. The tetrodotoxin (TTX) sensitivity and the stationary and kinetic characteristics of this current were similar to corresponding properties of hippocampal neurons. These quantitative data demonstrate that at an early postnatal stage of central nervous system maturation, glial cells in situ express a complex pattern of voltage-gated ion channels. The results are compared to findings in other preparations and the possible consequences of transmitter-mediated channel modulation in glial cells are discussed.

Time- and dose-dependent changes in neuronal activity produced by X radiation in brain slices.

PubMed

Pellmar, T C; Schauer, D A; Zeman, G H

1990-05-01

A new method of exposing tissues to X rays in a lead Faraday cage has made it possible to examine directly radiation damage to isolated neuronal tissue. Thin slices of hippocampus from brains of euthanized guinea pigs were exposed to 17.4 ke V X radiation. Electrophysiological recordings were made before, during, and after exposure to doses between 5 and 65 Gy at a dose rate of 1.54 Gy/min. Following exposure to doses of 40 Gy and greater, the synaptic potential was enhanced, reaching a steady level soon after exposure. The ability of the synaptic potential to generate a spike was reduced and damage progressed after termination of the radiation exposure. Recovery was not observed following termination of exposure. These results demonstrate that an isolated neuronal network can show complex changes in electrophysiological properties following moderate doses of ionizing radiation. An investigation of radiation damage directly to neurons in vitro will contribute to the understanding of the underlying mechanisms of radiation-induced nervous system dysfunction.

Mapping fundamental life elements in papillary thyroid carcinoma tissue

NASA Astrophysics Data System (ADS)

Merolle, L.; Ragazzi, M.; Gianoncelli, A.; Altissimo, M.; Ciarrocchi, A.; Bedolla, D. E.; Marraccini, C.; Baricchi, R.; Pertinhez, T. A.

2018-05-01

Well-differentiated papillary thyroid carcinomas (PTCs) are the most common type of thyroid cancer. Thyroid function depends on the presence of certain trace elements necessary for both the synthesis and the metabolism of thyroid hormones. We conducted an observational translational study on formalin fixed paraffin embedded thyroid tissue slices collected from five patients who underwent surgical resection of thyroid gland after thyroid cancer diagnosis. A synchrotron-based XRF set up was used to map the distribution of oxygen, sodium, aluminum, selenium and magnesium in PTC sections. These experiments were performed at the TwinMic beamline (Elettra—Sincrotrone Trieste, Trieste, Italy). Our results show that Mg levels in PTC tissues are significantly higher than in the control ones. The results seem to provide highly valuable information suggesting that Mg may play a role in the development and metabolic process of PTC.

Automated method for relating regional pulmonary structure and function: integration of dynamic multislice CT and thin-slice high-resolution CT

NASA Astrophysics Data System (ADS)

Tajik, Jehangir K.; Kugelmass, Steven D.; Hoffman, Eric A.

1993-07-01

We have developed a method utilizing x-ray CT for relating pulmonary perfusion to global and regional anatomy, allowing for detailed study of structure to function relationships. A thick slice, high temporal resolution mode is used to follow a bolus contrast agent for blood flow evaluation and is fused with a high spatial resolution, thin slice mode to obtain structure- function detail. To aid analysis of blood flow, we have developed a software module, for our image analysis package (VIDA), to produce the combined structure-function image. Color coded images representing blood flow, mean transit time, regional tissue content, regional blood volume, regional air content, etc. are generated and imbedded in the high resolution volume image. A text file containing these values along with a voxel's 3-D coordinates is also generated. User input can be minimized to identifying the location of the pulmonary artery from which the input function to a blood flow model is derived. Any flow model utilizing one input and one output function can be easily added to a user selectable list. We present examples from our physiologic based research findings to demonstrate the strengths of combining dynamic CT and HRCT relative to other scanning modalities to uniquely characterize pulmonary normal and pathophysiology.

Procedure for quantitative determination of effectiveness of photoinduced destruction of malignant tumors

NASA Astrophysics Data System (ADS)

Bizyuk, S. A.; Istomin, Yu. P.; Dzhagarov, B. M.

2006-07-01

We have developed a procedure for analysis of the functional status of blood vessels in tumor tissues using computer-assisted color scanning of tumor slices and also for a quantitative assessment of the effectiveness of photoinduced destruction of tumor tissues in animal experiments. Its major advantage is direct determination of the size of the tumor necrosis zone. The procedure has been tested in an experiment on three strains of malignant tumors with different morphologies.

Whole-organ atlas imaged by label-free high-resolution photoacoustic microscopy assisted by a microtome

NASA Astrophysics Data System (ADS)

Wong, Terence T. W.; Zhang, Ruiying; Hsu, Hsun-Chia; Maslov, Konstantin I.; Shi, Junhui; Chen, Ruimin; Shung, K. Kirk; Zhou, Qifa; Wang, Lihong V.

2018-02-01

In biomedical imaging, all optical techniques face a fundamental trade-off between spatial resolution and tissue penetration. Therefore, obtaining an organelle-level resolution image of a whole organ has remained a challenging and yet appealing scientific pursuit. Over the past decade, optical microscopy assisted by mechanical sectioning or chemical clearing of tissue has been demonstrated as a powerful technique to overcome this dilemma, one of particular use in imaging the neural network. However, this type of techniques needs lengthy special preparation of the tissue specimen, which hinders broad application in life sciences. Here, we propose a new label-free three-dimensional imaging technique, named microtomy-assisted photoacoustic microscopy (mPAM), for potentially imaging all biomolecules with 100% endogenous natural staining in whole organs with high fidelity. We demonstrate the first label-free mPAM, using UV light for label-free histology-like imaging, in whole organs (e.g., mouse brains), most of them formalin-fixed and paraffin- or agarose-embedded for minimal morphological deformation. Furthermore, mPAM with dual wavelength illuminations is also employed to image a mouse brain slice, demonstrating the potential for imaging of multiple biomolecules without staining. With visible light illumination, mPAM also shows its deep tissue imaging capability, which enables less slicing and hence reduces sectioning artifacts. mPAM could potentially provide a new insight for understanding complex biological organs.

Automatic 3D kidney segmentation based on shape constrained GC-OAAM

NASA Astrophysics Data System (ADS)

Chen, Xinjian; Summers, Ronald M.; Yao, Jianhua

2011-03-01

The kidney can be classified into three main tissue types: renal cortex, renal medulla and renal pelvis (or collecting system). Dysfunction of different renal tissue types may cause different kidney diseases. Therefore, accurate and efficient segmentation of kidney into different tissue types plays a very important role in clinical research. In this paper, we propose an automatic 3D kidney segmentation method which segments the kidney into the three different tissue types: renal cortex, medulla and pelvis. The proposed method synergistically combines active appearance model (AAM), live wire (LW) and graph cut (GC) methods, GC-OAAM for short. Our method consists of two main steps. First, a pseudo 3D segmentation method is employed for kidney initialization in which the segmentation is performed slice-by-slice via a multi-object oriented active appearance model (OAAM) method. An improved iterative model refinement algorithm is proposed for the AAM optimization, which synergistically combines the AAM and LW method. Multi-object strategy is applied to help the object initialization. The 3D model constraints are applied to the initialization result. Second, the object shape information generated from the initialization step is integrated into the GC cost computation. A multi-label GC method is used to segment the kidney into cortex, medulla and pelvis. The proposed method was tested on 19 clinical arterial phase CT data sets. The preliminary results showed the feasibility and efficiency of the proposed method.

Contribution of Intrinsic Lactate to Maintenance of Seizure Activity in Neocortical Slices from Patients with Temporal Lobe Epilepsy and in Rat Entorhinal Cortex.

PubMed

Angamo, Eskedar Ayele; ul Haq, Rizwan; Rösner, Jörg; Gabriel, Siegrun; Gerevich, Zoltán; Heinemann, Uwe; Kovács, Richard

2017-08-23

Neuronal lactate uptake supports energy metabolism associated with synaptic signaling and recovery of extracellular ion gradients following neuronal activation. Altered expression of the monocarboxylate transporters (MCT) in temporal lobe epilepsy (TLE) hampers lactate removal into the bloodstream. The resulting increase in parenchymal lactate levels might exert both, anti- and pro-ictogen effects, by causing acidosis and by supplementing energy metabolism, respectively. Hence, we assessed the contribution of lactate to the maintenance of transmembrane potassium gradients, synaptic signaling and pathological network activity in chronic epileptic human tissue. Stimulus induced and spontaneous field potentials and extracellular potassium concentration changes (∆[K⁺] O ) were recorded in parallel with tissue pO₂ and pH in slices from TLE patients while blocking MCTs by α-cyano-4-hydroxycinnamic acid (4-CIN) or d-lactate. Intrinsic lactate contributed to the oxidative energy metabolism in chronic epileptic tissue as revealed by the changes in pO₂ following blockade of lactate uptake. However, unlike the results in rat hippocampus, ∆[K⁺] O recovery kinetics and field potential amplitude did not depend on the presence of lactate. Remarkably, inhibition of lactate uptake exerted pH-independent anti-seizure effects both in healthy rat and chronic epileptic tissue and this effect was partly mediated via adenosine 1 receptor activation following decreased oxidative metabolism.

Contribution of Intrinsic Lactate to Maintenance of Seizure Activity in Neocortical Slices from Patients with Temporal Lobe Epilepsy and in Rat Entorhinal Cortex

PubMed Central

Angamo, Eskedar Ayele; Haq, Rizwan ul; Rösner, Jörg; Gabriel, Siegrun; Gerevich, Zoltán; Heinemann, Uwe

2017-01-01

Neuronal lactate uptake supports energy metabolism associated with synaptic signaling and recovery of extracellular ion gradients following neuronal activation. Altered expression of the monocarboxylate transporters (MCT) in temporal lobe epilepsy (TLE) hampers lactate removal into the bloodstream. The resulting increase in parenchymal lactate levels might exert both, anti- and pro-ictogen effects, by causing acidosis and by supplementing energy metabolism, respectively. Hence, we assessed the contribution of lactate to the maintenance of transmembrane potassium gradients, synaptic signaling and pathological network activity in chronic epileptic human tissue. Stimulus induced and spontaneous field potentials and extracellular potassium concentration changes (∆[K+]O) were recorded in parallel with tissue pO2 and pH in slices from TLE patients while blocking MCTs by α-cyano-4-hydroxycinnamic acid (4-CIN) or d-lactate. Intrinsic lactate contributed to the oxidative energy metabolism in chronic epileptic tissue as revealed by the changes in pO2 following blockade of lactate uptake. However, unlike the results in rat hippocampus, ∆[K+]O recovery kinetics and field potential amplitude did not depend on the presence of lactate. Remarkably, inhibition of lactate uptake exerted pH-independent anti-seizure effects both in healthy rat and chronic epileptic tissue and this effect was partly mediated via adenosine 1 receptor activation following decreased oxidative metabolism. PMID:28832554

OPTIMIZATION OF A PRECISION-CUT TROUT LIVER TISSUE SLICE ASSAY AS A SCREEN FOR VITELLOGENIN INDUCTION: COMPARISON OF SLIDE INCUBATION TECHNIQUES

EPA Science Inventory

The egg-yolk precursor protein vitellogenin (VTG) is normally only produced in the liver of female rainbow trout (RBT) in response to increasing 17B-estradiol (E2) during sexual maturation. However, its...

High Resolution Radioluminescence Microscopy for the Study of Prostate Tissue Slice Cell Metabolism and Monitoring of Treatment Response

DTIC Science & Technology

2016-12-01

REPORT DATE : December 2016 TYPE OF REPORT: Final PREPARED FOR: U.S. Army Medical Research and Materiel Command Fort Detrick, Maryland 21702-5012...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) December 2016 2. REPORT...TYPE Final 3. DATES COVERED (From - To) 30Sept2014 - 29Sept2016 4. TITLE AND SUBTITLE Monitoring of Treatment Response 5a. CONTRACT NUMBER High

High-Resolution Radioluminescence Microscopy for the Study of Prostate Tissue Slice Cell Metabolism and Monitoring of Treatment Response

DTIC Science & Technology

2015-09-01

University, The Stanford CA 94305-2004 REPORT DATE : October 2015 TYPE OF REPORT: annual PREPARED FOR: U.S. Army Medical Research and Materiel... DATE (DD-MM-YYYY) October 2015 2. REPORT TYPE Annual Report 3. DATES COVERED (From - To) 30 Sep 2014 - 29 Sep 2015 4. TITLE AND SUBTITLE Monitoring...ABSTRACT Currently, prostate cancers are classified using the Gleason Grade system and immunohistochemistry. The shortcoming of this method is that

Evaluation of a pulmonary strain model by registration of dynamic CT scans

NASA Astrophysics Data System (ADS)

Pomeroy, Marc; Liang, Zhengrong; Brehm, Anthony

2017-03-01

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease that develops in adults without any known cause. It is an interstitial lung disease in which the lung tissue becomes scarred and stiffens, ultimately leading to respiratory failure. This disease currently has no cure with limited treatment options, leading to an average survival time of 3-5 years after diagnosis. In this paper we employ a mathematical model simulating the lung parenchyma as hexagons with elastic forces applied to connecting vertices and opposing vertices. Using an image registration algorithm, we obtain trajectories of 4D-CT scans of a healthy patient, and one suffering from IPF. Converting the image trajectories into a hexagonal lattice, we fit the model parameters to match the respiratory motion seen for both patients across multiple image slices. We found the model could decently describe the healthy lung slices, with a minimum average error between corresponding vertices to be 1.66 mm. For the fibrotic lung slices the model was less accurate, maintaining a higher average error across all slices. Using the optimized parameters, we apply the forces predicted from the model using the image trajectory positions for each phase. Although the error is large, the spring constant values determined for the fibrotic patient were not as high as we expected, and more often than not determined to be lower than corresponding healthy lung slices. However, the net force distribution for some of those slices was still found to be greater than the healthy lung counterparts. Other modifications to the model, including additional directional components and which vertices were receiving with the limited sample size available, a clear distinction between the healthy and fibrotic lung cannot yet be made by this model.

[Simulation and data analysis of stereological modeling based on virtual slices].

PubMed

Wang, Hao; Shen, Hong; Bai, Xiao-yan

2008-05-01

To establish a computer-assisted stereological model for simulating the process of slice section and evaluate the relationship between section surface and estimated three-dimensional structure. The model was designed by mathematic method as a win32 software based on the MFC using Microsoft visual studio as IDE for simulating the infinite process of sections and analysis of the data derived from the model. The linearity of the fitting of the model was evaluated by comparison with the traditional formula. The win32 software based on this algorithm allowed random sectioning of the particles distributed randomly in an ideal virtual cube. The stereological parameters showed very high throughput (>94.5% and 92%) in homogeneity and independence tests. The data of density, shape and size of the section were tested to conform to normal distribution. The output of the model and that from the image analysis system showed statistical correlation and consistency. The algorithm we described can be used for evaluating the stereologic parameters of the structure of tissue slices.

Structure-activity relationship of cyanine tau aggregation inhibitors

PubMed Central

Chang, Edward; Congdon, Erin E.; Honson, Nicolette S.; Duff, Karen E.; Kuret, Jeff

2009-01-01

A structure-activity relationship for symmetrical cyanine inhibitors of human tau aggregation was elaborated using a filter trap assay. Antagonist activity depended on cyanine heterocycle, polymethine bridge length, and the nature of meso- and N-substituents. One potent member of the series, 3,3’-diethyl-9-methylthiacarbocyanine iodide (compound 11), retained submicromolar potency and had calculated physical properties consistent with blood-brain barrier and cell membrane penetration. Exposure of organotypic slices prepared from JNPL3 transgenic mice (which express human tau harboring the aggregation prone P301L tauopathy mutation) to compound 11 for one week revealed a biphasic dose response relationship. Low nanomolar concentrations decreased insoluble tau aggregates to half those observed in slices treated with vehicle alone. In contrast, high concentrations (≥300 nM) augmented tau aggregation and produced abnormalities in tissue tubulin levels. These data suggest that certain symmetrical carbocyanine dyes can modulate tau aggregation in the slice biological model at concentrations well below those associated with toxicity. PMID:19432420

Two-photon imaging in living brain slices.

PubMed

Mainen, Z F; Maletic-Savatic, M; Shi, S H; Hayashi, Y; Malinow, R; Svoboda, K

1999-06-01

Two-photon excitation laser scanning microscopy (TPLSM) has become the tool of choice for high-resolution fluorescence imaging in intact neural tissues. Compared with other optical techniques, TPLSM allows high-resolution imaging and efficient detection of fluorescence signal with minimal photobleaching and phototoxicity. The advantages of TPLSM are especially pronounced in highly scattering environments such as the brain slice. Here we describe our approaches to imaging various aspects of synaptic function in living brain slices. To combine several imaging modes together with patch-clamp electrophysiological recordings we found it advantageous to custom-build an upright microscope. Our design goals were primarily experimental convenience and efficient collection of fluorescence. We describe our TPLSM imaging system and its performance in detail. We present dynamic measurements of neuronal morphology of neurons expressing green fluorescent protein (GFP) and GFP fusion proteins as well as functional imaging of calcium dynamics in individual dendritic spines. Although our microscope is a custom instrument, its key advantages can be easily implemented as a modification of commercial laser scanning microscopes. Copyright 1999 Academic Press.

Organotypic Slice Cultures for Studies of Postnatal Neurogenesis

PubMed Central

Mosa, Adam J.; Wang, Sabrina; Tan, Yao Fang; Wojtowicz, J. Martin

2015-01-01

Here we describe a technique for studying hippocampal postnatal neurogenesis in the rodent brain using the organotypic slice culture technique. This method maintains the characteristic topographical morphology of the hippocampus while allowing direct application of pharmacological agents to the developing hippocampal dentate gyrus. Additionally, slice cultures can be maintained for up to 4 weeks and thus, allow one to study the maturation process of newborn granule neurons. Slice cultures allow for efficient pharmacological manipulation of hippocampal slices while excluding complex variables such as uncertainties related to the deep anatomic location of the hippocampus as well as the blood brain barrier. For these reasons, we sought to optimize organotypic slice cultures specifically for postnatal neurogenesis research. PMID:25867138

Fluorescence intensity and bright spot analyses using a confocal microscope for photodynamic diagnosis of brain tumors.

PubMed

Yoneyama, Takeshi; Watanabe, Tetsuyo; Kagawa, Hiroyuki; Hayashi, Yutaka; Nakada, Mitsutoshi

2017-03-01

In photodynamic diagnosis using 5-aminolevulinic acid (5-ALA), discrimination between the tumor and normal tissue is very important for a precise resection. However, it is difficult to distinguish between infiltrating tumor and normal regions in the boundary area. In this study, fluorescent intensity and bright spot analyses using a confocal microscope is proposed for the precise discrimination between infiltrating tumor and normal regions. From the 5-ALA-resected brain tumor tissue, the red fluorescent and marginal regions were sliced for observation under a confocal microscope. Hematoxylin and eosin (H&E) staining were performed on serial slices of the same tissue. According to the pathological inspection of the H&E slides, the tumor and infiltrating and normal regions on confocal microscopy images were investigated. From the fluorescent intensity of the image pixels, a histogram of pixel number with the same fluorescent intensity was obtained. The fluorescent bright spot sizes and total number were compared between the marginal and normal regions. The fluorescence intensity distribution and average intensity in the tumor were different from those in the normal region. The probability of a difference from the dark enhanced the difference between the tumor and the normal region. The bright spot size and number in the infiltrating tumor were different from those in the normal region. Fluorescence intensity analysis is useful to distinguish a tumor region, and a bright spot analysis is useful to distinguish between infiltrating tumor and normal regions. These methods will be important for the precise resection or photodynamic therapy of brain tumors. Copyright © 2016 Elsevier B.V. All rights reserved.

Tissue refractometry using Hilbert phase microscopy.

PubMed

Lue, Niyom; Bewersdorf, Joerg; Lessard, Mark D; Badizadegan, Kamran; Dasari, Ramachandra R; Feld, Michael S; Popescu, Gabriel

2007-12-15

We present, for the first time to our knowledge, quantitative phase images associated with unstained 5 mum thick tissue slices of mouse brain, spleen, and liver. The refractive properties of the tissue are retrieved in terms of the average refractive index and its spatial variation. We find that the average refractive index varies significantly with tissue type, such that the brain is characterized by the lowest value and the liver by the highest. The spatial power spectra of the phase images reveal power law behavior with different exponents for each tissue type. This approach opens a new possibility for stain-free characterization of tissues, where the diagnostic power is provided by the intrinsic refractive properties of the biological structure. We present results obtained for liver tissue affected by a lysosomal storage disease and show that our technique can quantify structural changes during this disease development.

Dexamethasone-mediated inhibition of Glioblastoma neurosphere dispersal in an ex vivo organotypic neural assay

PubMed Central

Meleis, Ahmed M.; Mahtabfar, Aria; Danish, Shabbar

2017-01-01

Glioblastoma is highly aggressive. Early dispersal of the primary tumor renders localized therapy ineffective. Recurrence always occurs and leads to patient death. Prior studies have shown that dispersal of Glioblastoma can be significantly reduced by Dexamethasone (Dex), a drug currently used to control brain tumor related edema. However, due to high doses and significant side effects, treatment is tapered and discontinued as soon as edema has resolved. Prior analyses of the dispersal inhibitory effects of Dex were performed on tissue culture plastic, or polystyrene filters seeded with normal human astrocytes, conditions which inherently differ from the parenchymal architecture of neuronal tissue. The aim of this study was to utilize an ex-vivo model to examine Dex-mediated inhibition of tumor cell migration from low-passage, human Glioblastoma neurospheres on multiple substrates including mouse retina, and slices of mouse, pig, and human brain. We also determined the lowest possible Dex dose that can inhibit dispersal. Analysis by Two-Factor ANOVA shows that for GBM-2 and GBM-3, Dex treatment significantly reduces dispersal on all tissue types. However, the magnitude of the effect appears to be tissue-type specific. Moreover, there does not appear to be a difference in Dex-mediated inhibition of dispersal between mouse retina, mouse brain and human brain. To estimate the lowest possible dose at which Dex can inhibit dispersal, LogEC50 values were compared by Extra Sum-of-Squares F-test. We show that it is possible to achieve 50% reduction in dispersal with Dex doses ranging from 3.8 x10-8M to 8.0x10-9M for GBM-2, and 4.3x10-8M to 1.8x10-9M for GBM-3, on mouse retina and brain slices, respectively. These doses are 3-30-fold lower than those used to control edema. This study extends our previous in vitro data and identifies the mouse retina as a potential substrate for in vivo studies of GBM dispersal. PMID:29040322

Optimizing and Evaluating an Integrated SPECT-CmT System Dedicated to Improved 3-D Breast Cancer Imaging

DTIC Science & Technology

2009-05-01

sagittal slices of a breast cancer patient (42yrs, 68kg) with implant and biopsy clip and various identified tissues . Glandular Adipose Implant...Biopsy Clip 13 volumetric imaging to effectively differentiate between normal glandular, adipose tissue and the artificial implants. It is...impacting the lowered head section. A. SPECT Sub-System The main component of the SPECT sub-system is a compact 16x20cm2 field of view Cadmium - Zinc

Virtual tissue alignment and cutting plane definition – a new method to obtain optimal longitudinal histological sections

PubMed Central

Danz, J C; Habegger, M; Bosshardt, D D; Katsaros, C; Stavropoulos, A

2014-01-01

Histomorphometric evaluation of the buccal aspects of periodontal tissues in rodents requires reproducible alignment of maxillae and highly precise sections containing central sections of buccal roots; this is a cumbersome and technically sensitive process due to the small specimen size. The aim of the present report is to describe and analyze a method to transfer virtual sections of micro-computer tomographic (CT)-generated image stacks to the microtome for undecalcified histological processing and to describe the anatomy of the periodontium in rat molars. A total of 84 undecalcified sections of all buccal roots of seven untreated rats was analyzed. The accuracy of section coordinate transfer from virtual micro-CT slice to the histological slice, right–left side differences and the measurement error for linear and angular measurements on micro-CT and on histological micrographs were calculated using the Bland–Altman method, interclass correlation coefficient and the method of moments estimator. Also, manual alignment of the micro-CT-scanned rat maxilla was compared with multiplanar computer-reconstructed alignment. The supra alveolar rat anatomy is rather similar to human anatomy, whereas the alveolar bone is of compact type and the keratinized gingival epithelium bends apical to join the junctional epithelium. The high methodological standardization presented herein ensures retrieval of histological slices with excellent display of anatomical microstructures, in a reproducible manner, minimizes random errors, and thereby may contribute to the reduction of number of animals needed. PMID:24266502

Integrated fMRI Preprocessing Framework Using Extended Kalman Filter for Estimation of Slice-Wise Motion

PubMed Central

Pinsard, Basile; Boutin, Arnaud; Doyon, Julien; Benali, Habib

2018-01-01

Functional MRI acquisition is sensitive to subjects' motion that cannot be fully constrained. Therefore, signal corrections have to be applied a posteriori in order to mitigate the complex interactions between changing tissue localization and magnetic fields, gradients and readouts. To circumvent current preprocessing strategies limitations, we developed an integrated method that correct motion and spatial low-frequency intensity fluctuations at the level of each slice in order to better fit the acquisition processes. The registration of single or multiple simultaneously acquired slices is achieved online by an Iterated Extended Kalman Filter, favoring the robust estimation of continuous motion, while an intensity bias field is non-parametrically fitted. The proposed extraction of gray-matter BOLD activity from the acquisition space to an anatomical group template space, taking into account distortions, better preserves fine-scale patterns of activity. Importantly, the proposed unified framework generalizes to high-resolution multi-slice techniques. When tested on simulated and real data the latter shows a reduction of motion explained variance and signal variability when compared to the conventional preprocessing approach. These improvements provide more stable patterns of activity, facilitating investigation of cerebral information representation in healthy and/or clinical populations where motion is known to impact fine-scale data. PMID:29755312

Integrated fMRI Preprocessing Framework Using Extended Kalman Filter for Estimation of Slice-Wise Motion.

PubMed

Pinsard, Basile; Boutin, Arnaud; Doyon, Julien; Benali, Habib

2018-01-01

Functional MRI acquisition is sensitive to subjects' motion that cannot be fully constrained. Therefore, signal corrections have to be applied a posteriori in order to mitigate the complex interactions between changing tissue localization and magnetic fields, gradients and readouts. To circumvent current preprocessing strategies limitations, we developed an integrated method that correct motion and spatial low-frequency intensity fluctuations at the level of each slice in order to better fit the acquisition processes. The registration of single or multiple simultaneously acquired slices is achieved online by an Iterated Extended Kalman Filter, favoring the robust estimation of continuous motion, while an intensity bias field is non-parametrically fitted. The proposed extraction of gray-matter BOLD activity from the acquisition space to an anatomical group template space, taking into account distortions, better preserves fine-scale patterns of activity. Importantly, the proposed unified framework generalizes to high-resolution multi-slice techniques. When tested on simulated and real data the latter shows a reduction of motion explained variance and signal variability when compared to the conventional preprocessing approach. These improvements provide more stable patterns of activity, facilitating investigation of cerebral information representation in healthy and/or clinical populations where motion is known to impact fine-scale data.

Effects of feeding pelleted diets without or with distillers dried grains with solubles on fresh belly characteristics, fat quality, and commercial bacon slicing yields of finishing pigs.

PubMed

Overholt, M F; Lowell, J E; Wilson, K B; Matulis, R J; Stein, H H; Dilger, A C; Boler, D D

2016-05-01

One hundred ninety-two pigs were blocked by age and stratified by initial BW (25.7 ± 2.3 kg) into pens (2 barrows and 2 gilts/pen), and within blocks, pens were assigned randomly to 1 of 4 treatments in a 2 × 2 factorial arrangement, with main effects of diet form (meal vs. pelleted) and distillers dried grains with solubles (DDGS) inclusion (0% vs. 30%). Pigs were slaughtered after a 91-d feeding trial, and carcasses were fabricated after a 24-h chilling period. Belly dimensions and flop distance were measured, and an adipose tissue sample from each belly was collected for fatty acid analysis. Bacon was manufactured at a commercial processing facility before being returned to the University of Illinois Meat Science Laboratory for further evaluation. Although bellies from pigs fed pelleted diets were 5.3% heavier ( < 0.01) than bellies from meal-fed pigs, belly weight as a percentage of chilled side weight ( = 0.55) and fresh belly dimensions ( ≥ 0.11) were not affected by diet form. Slab bacon weight and cooked yield were greater ( ≤ 0.01) for bellies from pellet-fed than meal-fed pigs. Despite pellet-fed pigs having a 3.1-unit greater iodine value (IV) than meal-fed pigs, there was no effect ( ≥ 0.16) of diet form on commercial bacon slicing yields. Bacon slabs from pellet-fed pigs produced more ( < 0.01) total bacon slices, but 3.1% fewer ( < 0.01) slices per kilogram than slabs from meal fed pigs. Inclusion of 30% DDGS reduced belly thickness ( < 0.001), flop distance ( < 0.001), and initial belly weight ( = 0.04) by 0.32 cm, 4.97 cm, and 2.85, respectively, and increased ( < 0.001) belly fat IV by 7.1 units compared with bellies from pigs fed 0% DDGS. Feeding 0% DDGS produced more ( < 0.01) total bacon slices than feeding 30% DDGS. Distillers dried grains with solubles inclusion had no effect on slice yields ( ≥ 0.14) or slices per kilogram ( = 0.08). Overall, bellies from pellet-fed pigs were heavier and had greater IV but did not differ in commercial slicing yields from meal-fed pigs. Feeding pigs 30% DDGS produced thinner, softer bellies with greater IV, but slicing yields were not different from bellies of pigs fed 0% DDGS. Thus, swine producers can feed pelleted diets, without or with 30% DDGS, without negatively affecting commercial bacon slicing yield.

Micro-polarimetry for pre-clinical diagnostics of pathological changes in human tissues

NASA Astrophysics Data System (ADS)

Golnik, Andrzej; Golnik, Natalia; Pałko, Tadeusz; Sołtysiński, Tomasz

2008-05-01

The paper presents a practical study of several methods of image analysis applied to polarimetric images of regular and malignant human tissues. The images of physiological and pathologically changed tissues from body and cervix of uterus, intestine, kidneys and breast were recorded in transmitted light of different polarization state. The set up of the conventional optical microscope with CCD camera and rotating polarizer's were used for analysis of the polarization state of the light transmitted through the tissue slice for each pixel of the camera image. The set of images corresponding to the different coefficients of the Stockes vectors, a 3×3 subset of the Mueller matrix as well as the maps of the magnitude and in-plane direction of the birefringent components in the sample were calculated. Then, the statistical analysis and the Fourier transform as well as the autocorrelation methods were used to analyze spatial distribution of birefringent elements in the tissue samples. For better recognition of tissue state we proposed a novel method that takes advantage of multiscale image data decomposition The results were used for selection of the optical characteristics with significantly different values for regular and malignant tissues.

Acoustic property reconstruction of a neonate Yangtze finless porpoise's (Neophocaena asiaeorientalis) head based on CT imaging.

PubMed

Wei, Chong; Wang, Zhitao; Song, Zhongchang; Wang, Kexiong; Wang, Ding; Au, Whitlow W L; Zhang, Yu

2015-01-01

The reconstruction of the acoustic properties of a neonate finless porpoise's head was performed using X-ray computed tomography (CT). The head of the deceased neonate porpoise was also segmented across the body axis and cut into slices. The averaged sound velocity and density were measured, and the Hounsfield units (HU) of the corresponding slices were obtained from computed tomography scanning. A regression analysis was employed to show the linear relationships between the Hounsfield unit and both sound velocity and density of samples. Furthermore, the CT imaging data were used to compare the HU value, sound velocity, density and acoustic characteristic impedance of the main tissues in the porpoise's head. The results showed that the linear relationships between HU and both sound velocity and density were qualitatively consistent with previous studies on Indo-pacific humpback dolphins and Cuvier's beaked whales. However, there was no significant increase of the sound velocity and acoustic impedance from the inner core to the outer layer in this neonate finless porpoise's melon.

Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators.

PubMed

Chamberland, Simon; Yang, Helen H; Pan, Michael M; Evans, Stephen W; Guan, Sihui; Chavarha, Mariya; Yang, Ying; Salesse, Charleen; Wu, Haodi; Wu, Joseph C; Clandinin, Thomas R; Toth, Katalin; Lin, Michael Z; St-Pierre, François

2017-07-27

Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila . These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision.

Study of a scanning HIFU therapy protocol, Part II: Experiment and results

NASA Astrophysics Data System (ADS)

Andrew, Marilee A.; Kaczkowski, Peter; Cunitz, Bryan W.; Brayman, Andrew A.; Kargl, Steven G.

2003-04-01

Instrumentation and protocols for creating scanned HIFU lesions in freshly excised bovine liver were developed in order to study the in vitro HIFU dose response and validate models. Computer-control of the HIFU transducer and 3-axis positioning system provided precise spatial placement of the thermal lesions. Scan speeds were selected in the range of 1 to 8 mm/s, and the applied electrical power was varied from 20 to 60 W. These parameters were chosen to hold the thermal dose constant. A total of six valid scans of 15 mm length were created in each sample; a 3.5 MHz single-element, spherically focused transducer was used. Treated samples were frozen, then sliced in 1.27 mm increments. Digital photographs of slices were downloaded to computer for image processing and analysis. Lesion characteristics, including the depth within the tissue, axial length, and radial width, were computed. Results were compared with those generated from modified KZK and BHTE models, and include a comparison of the statistical variation in the across-scan lesion radial width. [Work supported by USAMRMC.

A Comparison of Different Slicing Planes in Preservation of Major Hippocampal Pathway Fibers in the Mouse

PubMed Central

Xiong, Guoxiang; Metheny, Hannah; Johnson, Brian N.; Cohen, Akiva S.

2017-01-01

The hippocampus plays a critical role in learning and memory and higher cognitive functions, and its dysfunction has been implicated in various neuropathological disorders. Electrophysiological recording undertaken in live brain slices is one of the most powerful tools for investigating hippocampal cellular and network activities. The plane for cutting the slices determines which afferent and/or efferent connections are best preserved, and there are three commonly used slices: hippocampal-entorhinal cortex (HEC), coronal and transverse. All three slices have been widely used for studying the major afferent hippocampal pathways including the perforant path (PP), the mossy fibers (MFs) and the Schaffer collaterals (SCs). Surprisingly, there has never been a systematic investigation of the anatomical and functional consequences of slicing at a particular angle. In the present study, we focused on how well fiber pathways are preserved from the entorhinal cortex (EC) to the hippocampus, and within the hippocampus, in slices generated by sectioning at different angles. The postmortem neural tract tracer 1,1′-dioctadecyl-3,3,3′3′-tetramethylindocarbocyanine perchlorate (DiI) was used to label afferent fibers to hippocampal principal neurons in fixed slices or whole brains. Laser scanning confocal microscopy was adopted for imaging DiI-labeled axons and terminals. We demonstrated that PP fibers were well preserved in HEC slices, MFs in both HEC and transverse slices and SCs in all three types of slices. Correspondingly, field excitatory postsynaptic potentials (fEPSPs) could be consistently evoked in HEC slices when stimulating PP fibers and recorded in stratum lacunosum-moleculare (sl-m) of area CA1, and when stimulating the dentate granule cell layer (gcl) and recording in stratum lucidum (sl) of area CA3. The MF evoked fEPSPs could not be recorded in CA3 from coronal slices. In contrast to our DiI-tracing data demonstrating severely truncated PP fibers in coronal slices, fEPSPs could still be recorded in CA1 sl-m in this plane, suggesting that an additional afferent fiber pathway other than PP might be involved. The present study increases our understanding of which hippocampal pathways are best preserved in the three most common brain slice preparations, and will help investigators determine the appropriate slices to use for physiological studies depending on the subregion of interest. PMID:29201002

A new extracellular multirecording system for electrophysiological studies: application to hippocampal organotypic cultures.

PubMed

Stoppini, L; Duport, S; Corrèges, P

1997-03-01

The present paper describes a new multirecording device which performs continuous electrophysiological studies on organotypic cultures. This device is formed by a card (Physiocard) carrying the culture which is inserted into an electronic module. Electrical activities are recorded by an array of 30 biocompatible microelectrodes which are adjusted into close contact with the upper surface of the slice culture. The microelectrode array is integrated into the card enabling electrical stimulation and recording of neurons over periods ranging from several hours to a few days outside a Faraday cage. Neuronal responses are recorded and analyzed by a dedicated electronic and acquisition chain. A perfusion chamber is contained in the card, allowing continuous perfusion in sterile conditions. Electrophysiological extracellular recordings and some drugs' effects obtained with this system in hippocampal slice cultures were identical to conventional electrophysiological set-up results with tetrodotoxin, bicuculline, kainate, dexamethasone and NBQX. The Physiocard system allows new insights for studies on nervous tissue and allows sophisticated approaches to be used quicker and more easily. It could be used for various neurophysiological studies or screening tests such as neural network mapping, nervous recovery, epilepsy, neurotoxicity or neuropharmacology.

Three-dimensional inversion recovery manganese-enhanced MRI of mouse brain using super-resolution reconstruction to visualize nuclei involved in higher brain function.

PubMed

Poole, Dana S; Plenge, Esben; Poot, Dirk H J; Lakke, Egbert A J F; Niessen, Wiro J; Meijering, Erik; van der Weerd, Louise

2014-07-01

The visualization of activity in mouse brain using inversion recovery spin echo (IR-SE) manganese-enhanced MRI (MEMRI) provides unique contrast, but suffers from poor resolution in the slice-encoding direction. Super-resolution reconstruction (SRR) is a resolution-enhancing post-processing technique in which multiple low-resolution slice stacks are combined into a single volume of high isotropic resolution using computational methods. In this study, we investigated, first, whether SRR can improve the three-dimensional resolution of IR-SE MEMRI in the slice selection direction, whilst maintaining or improving the contrast-to-noise ratio of the two-dimensional slice stacks. Second, the contrast-to-noise ratio of SRR IR-SE MEMRI was compared with a conventional three-dimensional gradient echo (GE) acquisition. Quantitative experiments were performed on a phantom containing compartments of various manganese concentrations. The results showed that, with comparable scan times, the signal-to-noise ratio of three-dimensional GE acquisition is higher than that of SRR IR-SE MEMRI. However, the contrast-to-noise ratio between different compartments can be superior with SRR IR-SE MEMRI, depending on the chosen inversion time. In vivo experiments were performed in mice receiving manganese using an implanted osmotic pump. The results showed that SRR works well as a resolution-enhancing technique in IR-SE MEMRI experiments. In addition, the SRR image also shows a number of brain structures that are more clearly discernible from the surrounding tissues than in three-dimensional GE acquisition, including a number of nuclei with specific higher brain functions, such as memory, stress, anxiety and reward behavior. Copyright © 2014 John Wiley & Sons, Ltd.

Pregnant serum induces neuroinflammation and seizure activity via TNFα.

PubMed

Cipolla, Marilyn J; Pusic, Aya D; Grinberg, Yelena Y; Chapman, Abbie C; Poynter, Matthew E; Kraig, Richard P

2012-04-01

Preeclampsia is a hypertensive disorder of pregnancy that affects many organs including the brain. Neurological complications occur during preeclampsia, the most serious of which is seizure known as eclampsia. Although preeclampsia can precede the eclamptic seizure, it often occurs during normal pregnancy, suggesting that processes associated with normal pregnancy can promote neuronal excitability. Here we investigated whether circulating inflammatory mediators that are elevated late in gestation when seizure also occurs are hyperexcitable to neuronal tissue. Evoked field potentials were measured in hippocampal slices in which control horse serum that slices are normally grown in, was replaced with serum from nonpregnant or late-pregnant Wistar rats for 48 h. We found that serum from pregnant, but not nonpregnant rats, caused hyperexcitability to hippocampal neurons and seizure activity that was abrogated by inhibition of tumor necrosis factor alpha (TNFα) signaling. Additionally, application of TNFα mimicked this increased excitability. Pregnant serum also caused morphological changes in microglia characteristic of activation, and increased TNFα mRNA expression that was not seen with exposure to nonpregnant serum. However, TNFα protein was not found to be elevated in pregnant serum itself, suggesting that other circulating factors during pregnancy caused activation of hippocampal slice cells to produce a TNFα-mediated increase in neuronal excitability. Lastly, although pregnant serum caused neuroinflammation and hyperexcitability of hippocampal slices, it did not increase blood-brain barrier permeability, nor were pregnant rats from which the serum was taken undergoing seizure. Thus, the BBB has an important role in protecting the brain from circulating neuroinflammatory mediators that are hyperexcitable to the brain during pregnancy. These studies provide novel insight into the underlying cause of eclampsia without elevated blood pressure and the protective role of the BBB that prevents exposure of the brain to hyperexcitable factors. Copyright © 2012 Elsevier Inc. All rights reserved.

An experimental study: evaluating the tissue structure of penis with 2D-ShearWave™ Elastography.

PubMed

Qiao, X-H; Zhang, J-J; Gao, F; Li, F; Liu, Y; Xing, L-X; Du, L-F; Xing, J-F

2017-01-01

The aim of this study was to investigate the feasibility of two-dimensional-ShearWave™ Elastography (2D-SWE) on evaluating the change of tissue structure of penis. Twenty healthy male Sprague Dawley rats were divided into penis-developed group (PDG, 52 weeks) and penis-underdeveloped group (PUDG, 5 weeks). The ultrafast ultrasound device-Aixplorer® (SuperSonic Imagine) was used for 2D-SWE imaging of the penis, the measurement index was shear wave stiffness (SWS, kPa). All rat penises were cut off immediately after ultrasonic examination. After paraffin embedding, slicing and hematoxylin-eosin staining, the tissue structure of the penis was observed under light microscope. SWS of all rat penises were measured successfully. The results showed that SWS of PDG was significantly lower than PUDG (P=0.008). At the same time, the pathological results found that there were significant differences in the tissue structures (sinusoids, smooth muscle cells and fibrocytes) of the penises between the two groups. These results suggest that there are significant differences in SWS between different tissue structures of penis. 2D-SWE is expected to be used on the etiological diagnosis of erectile dysfunction by serving as a new noninvasive method of evaluating the change of tissue structure of penis.

High-resolution breast tomography at high energy: a feasibility study of phase contrast imaging on a whole breast

NASA Astrophysics Data System (ADS)

Sztrókay, A.; Diemoz, P. C.; Schlossbauer, T.; Brun, E.; Bamberg, F.; Mayr, D.; Reiser, M. F.; Bravin, A.; Coan, P.

2012-05-01

Previous studies on phase contrast imaging (PCI) mammography have demonstrated an enhancement of breast morphology and cancerous tissue visualization compared to conventional imaging. We show here the first results of the PCI analyser-based imaging (ABI) in computed tomography (CT) mode on whole and large (>12 cm) tumour-bearing breast tissues. We demonstrate in this work the capability of the technique of working at high x-ray energies and producing high-contrast images of large and complex specimens. One entire breast of an 80-year-old woman with invasive ductal cancer was imaged using ABI-CT with monochromatic 70 keV x-rays and an area detector of 92×92 µm2 pixel size. Sagittal slices were reconstructed from the acquired data, and compared to corresponding histological sections. Comparison with conventional absorption-based CT was also performed. Five blinded radiologists quantitatively evaluated the visual aspects of the ABI-CT images with respect to sharpness, soft tissue contrast, tissue boundaries and the discrimination of different structures/tissues. ABI-CT excellently depicted the entire 3D architecture of the breast volume by providing high-resolution and high-contrast images of the normal and cancerous breast tissues. These results are an important step in the evolution of PCI-CT towards its clinical implementation.

Minimizing photodecomposition of flavin adenine dinucleotide fluorescence by the use of pulsed LEDs.

PubMed

Rösner, J; Liotta, A; Angamo, E A; Spies, C; Heinemann, U; Kovács, R

2016-11-01

Dynamic alterations in flavin adenine dinucleotide (FAD) fluorescence permit insight into energy metabolism-dependent changes of intramitochondrial redox potential. Monitoring FAD fluorescence in living tissue is impeded by photobleaching, restricting the length of microfluorimetric recordings. In addition, photodecomposition of these essential electron carriers negatively interferes with energy metabolism and viability of the biological specimen. Taking advantage of pulsed LED illumination, here we determined the optimal excitation settings giving the largest fluorescence yield with the lowest photobleaching and interference with metabolism in hippocampal brain slices. The effects of FAD bleaching on energy metabolism and viability were studied by monitoring tissue pO 2 , field potentials and changes in extracellular potassium concentration ([K + ] o ). Photobleaching with continuous illumination consisted of an initial exponential decrease followed by a nearly linear decay. The exponential decay was significantly decelerated with pulsed illumination. Pulse length of 5 ms was sufficient to reach a fluorescence output comparable to continuous illumination, whereas further increasing duration increased photobleaching. Similarly, photobleaching increased with shortening of the interpulse interval. Photobleaching was partially reversible indicating the existence of a transient nonfluorescent flavin derivative. Pulsed illumination decreased FAD photodecomposition, improved slice viability and reproducibility of stimulus-induced FAD, field potential, [K + ] o and pO 2 changes as compared to continuous illumination. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Applicability of rat precision-cut lung slices in evaluating nanomaterial cytotoxicity, apoptosis, oxidative stress, and inflammation

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

Sauer, Ursula G.; Vogel, Sandra; Product Stewardship Water Solutions, BASF SE, Ludwigshafen

2014-04-01

The applicability of rat precision-cut lung slices (PCLuS) in detecting nanomaterial (NM) toxicity to the respiratory tract was investigated evaluating sixteen OECD reference NMs (TiO{sub 2}, ZnO, CeO{sub 2}, SiO{sub 2}, Ag, multi-walled carbon nanotubes (MWCNTs)). Upon 24-hour test substance exposure, the PCLuS system was able to detect early events of NM toxicity: total protein, reduction in mitochondrial activity, caspase-3/-7 activation, glutathione depletion/increase, cytokine induction, and histopathological evaluation. Ion shedding NMS (ZnO and Ag) induced severe tissue destruction detected by the loss of total protein. Two anatase TiO{sub 2} NMs, CeO{sub 2} NMs, and two MWCNT caused significant (determined bymore » trend analysis) cytotoxicity in the WST-1 assay. At non-cytotoxic concentrations, different TiO{sub 2} NMs and one MWCNT increased GSH levels, presumably a defense response to reactive oxygen species, and these substances further induced a variety of cytokines. One of the SiO{sub 2} NMs increased caspase-3/-7 activities at non-cytotoxic levels, and one rutile TiO{sub 2} only induced cytokines. Investigating these effects is, however, not sufficient to predict apical effects found in vivo. Reproducibility of test substance measurements was not fully satisfactory, especially in the GSH and cytokine assays. Effects were frequently observed in negative controls pointing to tissue slice vulnerability even though prepared and handled with utmost care. Comparisons of the effects observed in the PCLuS to in vivo effects reveal some concordances for the metal oxide NMs, but less so for the MWCNT. The highest effective dosages, however, exceeded those reported for rat short-term inhalation studies. To become applicable for NM testing, the PCLuS system requires test protocol optimization. - Highlights: • 16 OECD reference nanomaterials were tested in rat precision-cut lung slices. • Nanomaterial cytotoxicity, apoptose, oxidative stress, and inflammation were detected. • Investigating these early effects is not sufficient to predict in vivo outcome. • Reproducibility was not fully satisfactory in the glutathione and cytokine assays. • Further work is required to adjust effective dosages in vitro to in vivo doses.« less

Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry.

PubMed

Yanina, Irina Y; Popov, Alexey P; Bykov, Alexander V; Meglinski, Igor V; Tuchin, Valery V

2018-01-01

Observation of temperature-mediated phase transitions between lipid components of the adipose tissues has been performed by combined use of the Abbe refractometry and optical coherence tomography. The phase transitions of the lipid components were clearly observed in the range of temperatures from 24°C to 60°C, and assessed by quantitatively monitoring the changes of the refractive index of 1- to 2-mm-thick porcine fat tissue slices. The developed approach has a great potential as an alternative method for obtaining accurate information on the processes occurring during thermal lipolysis. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

2D Raman study of the healthy and epileptic rat cerebellar cortex tissue

NASA Astrophysics Data System (ADS)

Sacharz, Julia; Wesełucha-Birczyńska, Aleksandra; Zięba-Palus, Janina; Lewandowski, Marian H.; Palus-Chramiec, Katarzyna; Chrobok, Łukasz; Moskal, Paulina; Birczyńska, Malwina; Sozańska, Agnieszka

2018-07-01

The aim of this study was to determine what changes in the Cerebellar cortex (Cc) of the rat's brain tissue can be observed by Raman spectroscopy comparing epileptic (WAG/Rij) and control (Wistar) rats. Experiments were performed on the brain slices obtained from male rats (2-3 weeks old). WAG/Rij rats, used in this study, represent the well-established model of epilepsy. The Raman spectra of the fresh, not additionally preserved brain scraps, kept in artificial cerebrospinal fluid, were collected using a 442 nm, 514.5 nm, 785 nm and 1064 nm laser lines as an excitation source. 2D correlation analysis was used to create two-dimensional (2D) spectra and wavelength of the excitation laser was regarded as an external stimulus. Differences in the 2D spectra of two investigated groups of rats were observed. Analysis of the intensity ratios of the respective marker Raman bands indicated close packing between the lipid chains in a healthy Cerebellar cortex tissue. In asynchronous maps of healthy tissue the cross-peaks of Trp and Tyr vibration, that are neurotransmitters' precursors, are recognized. In the epileptic tissue, the amino acids glutamate (Glu) and aspartate (Asp), excitatory neurotransmitters, initiate changes observed in the asynchronous map.

Colour calibration of a laboratory computer vision system for quality evaluation of pre-sliced hams.

PubMed

Valous, Nektarios A; Mendoza, Fernando; Sun, Da-Wen; Allen, Paul

2009-01-01

Due to the high variability and complex colour distribution in meats and meat products, the colour signal calibration of any computer vision system used for colour quality evaluations, represents an essential condition for objective and consistent analyses. This paper compares two methods for CIE colour characterization using a computer vision system (CVS) based on digital photography; namely the polynomial transform procedure and the transform proposed by the sRGB standard. Also, it presents a procedure for evaluating the colour appearance and presence of pores and fat-connective tissue on pre-sliced hams made from pork, turkey and chicken. Our results showed high precision, in colour matching, for device characterization when the polynomial transform was used to match the CIE tristimulus values in comparison with the sRGB standard approach as indicated by their ΔE(ab)(∗) values. The [3×20] polynomial transfer matrix yielded a modelling accuracy averaging below 2.2 ΔE(ab)(∗) units. Using the sRGB transform, high variability was appreciated among the computed ΔE(ab)(∗) (8.8±4.2). The calibrated laboratory CVS, implemented with a low-cost digital camera, exhibited reproducible colour signals in a wide range of colours capable of pinpointing regions-of-interest and allowed the extraction of quantitative information from the overall ham slice surface with high accuracy. The extracted colour and morphological features showed potential for characterizing the appearance of ham slice surfaces. CVS is a tool that can objectively specify colour and appearance properties of non-uniformly coloured commercial ham slices.

Tissue refractometry using Hilbert phase microscopy

PubMed Central

Lue, Niyom; Bewersdorf, Joerg; Lessard, Mark D.; Badizadegan, Kamran; Dasari, Ramachandra R.; Feld, Michael S.; Popescu, Gabriel

2009-01-01

We present, for the first time to our knowledge, quantitative phase images associated with unstained 5 μm thick tissue slices of mouse brain, spleen, and liver. The refractive properties of the tissue are retrieved in terms of the average refractive index and its spatial variation. We find that the average refractive index varies significantly with tissue type, such that the brain is characterized by the lowest value and the liver by the highest. The spatial power spectra of the phase images reveal power law behavior with different exponents for each tissue type. This approach opens a new possibility for stain-free characterization of tissues, where the diagnostic power is provided by the intrinsic refractive properties of the biological structure. We present results obtained for liver tissue affected by a lysosomal storage disease and show that our technique can quantify structural changes during this disease development. PMID:18087529

Trajectory Analysis Unveils Reelin's Role in the Directed Migration of Granule Cells in the Dentate Gyrus.

PubMed

Wang, Shaobo; Brunne, Bianka; Zhao, Shanting; Chai, Xuejun; Li, Jiawei; Lau, Jeremie; Failla, Antonio Virgilio; Zobiak, Bernd; Sibbe, Mirjam; Westbrook, Gary L; Lutz, David; Frotscher, Michael

2018-01-03

Reelin controls neuronal migration and layer formation. Previous studies in reeler mice deficient in Reelin focused on the result of the developmental process in fixed tissue sections. It has remained unclear whether Reelin affects the migratory process, migration directionality, or migrating neurons guided by the radial glial scaffold. Moreover, Reelin has been regarded as an attractive signal because newly generated neurons migrate toward the Reelin-containing marginal zone. Conversely, Reelin might be a stop signal because migrating neurons in reeler , but not in wild-type mice, invade the marginal zone. Here, we monitored the migration of newly generated proopiomelanocortin-EGFP -expressing dentate granule cells in slice cultures from reeler , reeler -like mutants and wild-type mice of either sex using real-time microscopy. We discovered that not the actual migratory process and migratory speed, but migration directionality of the granule cells is controlled by Reelin. While wild-type granule cells migrated toward the marginal zone of the dentate gyrus, neurons in cultures from reeler and reeler -like mutants migrated randomly in all directions as revealed by vector analyses of migratory trajectories. Moreover, live imaging of granule cells in reeler slices cocultured to wild-type dentate gyrus showed that the reeler neurons changed their directions and migrated toward the Reelin-containing marginal zone of the wild-type culture, thus forming a compact granule cell layer. In contrast, directed migration was not observed when Reelin was ubiquitously present in the medium of reeler slices. These results indicate that topographically administered Reelin controls the formation of a granule cell layer. SIGNIFICANCE STATEMENT Neuronal migration and the various factors controlling its onset, speed, directionality, and arrest are poorly understood. Slice cultures offer a unique model to study the migration of individual neurons in an almost natural environment. In the present study, we took advantage of the expression of proopiomelanocortin-EGFP by newly generated, migrating granule cells to analyze their migratory trajectories in hippocampal slice cultures from wild-type mice and mutants deficient in Reelin signaling. We show that the compartmentalized presence of Reelin is essential for the directionality, but not the actual migratory process or speed, of migrating granule cells leading to their characteristic lamination in the dentate gyrus. Copyright © 2018 the authors 0270-6474/18/380137-12$15.00/0.

Optical slicing and 3-D characterization of hippocampal capillaries in the rat visualized by autometallographic silver enhancement of colloidal gold particles.

PubMed

Andreasen, A; Danscher, G

1997-10-01

In order to visualize the vascular system of the rat brain, 10 Wistar rats were perfused transcardially with glutaraldehyde and a 40 degrees C gold-gelatine solution. The brains were post-fixed with glutaraldehyde and vibratomized into 100-micron-thick slices, and the gold particles were developed by autometallography. In this way, the colloidal gold particles in the vessels became encased in silver and thereby made visible. The developed gold staining is stable and does not interfere with further dehydration and counterstaining. Images were frame grabbed during optical slicing, and classic stereograms and 'shadow' 3-D images were produced. We found a high variation of capillary density in the hippocampal region reflecting known subregional structures. The silver-enhanced vessels acted as natural markers and made it possible to study and measure aspects of the complexity of dehydration and staining artifacts. We found a non-linear shrinking of 13-17% in the x- and y-directions and a spatial shrinking up to 50% in some regions after the dehydration and staining process. This observation may be of interest not only in relation to tissue subjected to this fixation protocol but also to other fixation procedures. The gold-gelatine autometallographic technique and the present stereograms can release data for stereological use as well.

Ethylene and Wound-Induced Gene Expression in the Preclimacteric Phase of Ripening Avocado Fruit and Mesocarp Discs.

PubMed Central

Starrett, D. A.; Laties, G. G.

1993-01-01

Whereas intact postharvest avocado (Persea americana Mill.) fruit may take 1 or more weeks to ripen, ripening is hastened by pulsing fruit for 24 h with ethylene or propylene and is initiated promptly by cutting slices, or discs, of mesocarp tissue. Because the preclimacteric lag period constitutes the extended and variable component of the ripening syndrome, we postulated that selective gene expression during the lag period leads to the triggering of the climacteric. Accordingly, we sought to identify genes that are expressed gradually in the course of the lag period in intact fruit, are turned on sooner in response to a pulse, and are induced promptly in response to wounding (i.e. slicing). To this end, a mixed cDNA library was constructed from mRNA from untreated fruit, pulsed fruit, and aged slices, and the library was screened for genes induced by wounding or by pulsing and/or wounding. The time course of induction of genes encoding selected clones was established by probing northern blots of mRNA from tissues variously treated over a period of time. Four previously identified ripening-associated genes encoding cellulase, polygalacturonase (PG), cytochrome P-450 oxidase (P-450), and ethylene-forming enzyme (EFE, or 1-aminocyclopropane-1-carboxylic acid synthase), respectively, were studied in the same way. Whereas cellulase, PG, and EFE were ruled out as having a role in the initiation of the climacteric, the time course of P-450 induction, as well as the response of same to pulsing and wounding met the criteria[mdash]together with several clones from the mixed library[mdash]for a gene potentially involved in preclimacteric events leading to the onset of the climacteric. Further, it was established that the continuous presence of ethylene is required for persisting induction, and it is suggested that in selected cases wounding may exert a synergistic effect on ethylene action. PMID:12231929

Histology-derived volumetric annotation of the human hippocampal subfields in postmortem MRI.

PubMed

Adler, Daniel H; Pluta, John; Kadivar, Salmon; Craige, Caryne; Gee, James C; Avants, Brian B; Yushkevich, Paul A

2014-01-01

Recently, there has been a growing effort to analyze the morphometry of hippocampal subfields using both in vivo and postmortem magnetic resonance imaging (MRI). However, given that boundaries between subregions of the hippocampal formation (HF) are conventionally defined on the basis of microscopic features that often lack discernible signature in MRI, subfield delineation in MRI literature has largely relied on heuristic geometric rules, the validity of which with respect to the underlying anatomy is largely unknown. The development and evaluation of such rules are challenged by the limited availability of data linking MRI appearance to microscopic hippocampal anatomy, particularly in three dimensions (3D). The present paper, for the first time, demonstrates the feasibility of labeling hippocampal subfields in a high resolution volumetric MRI dataset based directly on microscopic features extracted from histology. It uses a combination of computational techniques and manual post-processing to map subfield boundaries from a stack of histology images (obtained with 200μm spacing and 5μm slice thickness; stained using the Kluver-Barrera method) onto a postmortem 9.4Tesla MRI scan of the intact, whole hippocampal formation acquired with 160μm isotropic resolution. The histology reconstruction procedure consists of sequential application of a graph-theoretic slice stacking algorithm that mitigates the effects of distorted slices, followed by iterative affine and diffeomorphic co-registration to postmortem MRI scans of approximately 1cm-thick tissue sub-blocks acquired with 200μm isotropic resolution. These 1cm blocks are subsequently co-registered to the MRI of the whole HF. Reconstruction accuracy is evaluated as the average displacement error between boundaries manually delineated in both the histology and MRI following the sequential stages of reconstruction. The methods presented and evaluated in this single-subject study can potentially be applied to multiple hippocampal tissue samples in order to construct a histologically informed MRI atlas of the hippocampal formation. © 2013 Elsevier Inc. All rights reserved.

Comparing thin slices of verbal communication behavior of varying number and duration.

PubMed

Carcone, April Idalski; Naar, Sylvie; Eggly, Susan; Foster, Tanina; Albrecht, Terrance L; Brogan, Kathryn E

2015-02-01

The aim of this study was to assess the accuracy of thin slices to characterize the verbal communication behavior of counselors and patients engaged in Motivational Interviewing sessions relative to fully coded sessions. Four thin slice samples that varied in number (four versus six slices) and duration (one- versus two-minutes) were extracted from a previously coded dataset. In the parent study, an observational code scheme was used to characterize specific counselor and patient verbal communication behaviors. For the current study, we compared the frequency of communication codes and the correlations among the full dataset and each thin slice sample. Both the proportion of communication codes and strength of the correlation demonstrated the highest degree of accuracy when a greater number (i.e., six versus four) and duration (i.e., two- versus one-minute) of slices were extracted. These results suggest that thin slice sampling may be a useful and accurate strategy to reduce coding burden when coding specific verbal communication behaviors within clinical encounters. We suggest researchers interested in using thin slice sampling in their own work conduct preliminary research to determine the number and duration of thin slices required to accurately characterize the behaviors of interest. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Principles, Techniques, and Applications of Tissue Microfluidics

NASA Technical Reports Server (NTRS)

Wade, Lawrence A.; Kartalov, Emil P.; Shibata, Darryl; Taylor, Clive

2011-01-01

The principle of tissue microfluidics and its resultant techniques has been applied to cell analysis. Building microfluidics to suit a particular tissue sample would allow the rapid, reliable, inexpensive, highly parallelized, selective extraction of chosen regions of tissue for purposes of further biochemical analysis. Furthermore, the applicability of the techniques ranges beyond the described pathology application. For example, they would also allow the posing and successful answering of new sets of questions in many areas of fundamental research. The proposed integration of microfluidic techniques and tissue slice samples is called "tissue microfluidics" because it molds the microfluidic architectures in accordance with each particular structure of each specific tissue sample. Thus, microfluidics can be built around the tissues, following the tissue structure, or alternatively, the microfluidics can be adapted to the specific geometry of particular tissues. By contrast, the traditional approach is that microfluidic devices are structured in accordance with engineering considerations, while the biological components in applied devices are forced to comply with these engineering presets.

SU-C-207B-04: Automated Segmentation of Pectoral Muscle in MR Images of Dense Breasts

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

Verburg, E; Waard, SN de; Veldhuis, WB

Purpose: To develop and evaluate a fully automated method for segmentation of the pectoral muscle boundary in Magnetic Resonance Imaging (MRI) of dense breasts. Methods: Segmentation of the pectoral muscle is an important part of automatic breast image analysis methods. Current methods for segmenting the pectoral muscle in breast MRI have difficulties delineating the muscle border correctly in breasts with a large proportion of fibroglandular tissue (i.e., dense breasts). Hence, an automated method based on dynamic programming was developed, incorporating heuristics aimed at shape, location and gradient features.To assess the method, the pectoral muscle was segmented in 91 randomly selectedmore » participants (mean age 56.6 years, range 49.5–75.2 years) from a large MRI screening trial in women with dense breasts (ACR BI-RADS category 4). Each MR dataset consisted of 178 or 179 T1-weighted images with voxel size 0.64 × 0.64 × 1.00 mm3. All images (n=16,287) were reviewed and scored by a radiologist. In contrast to volume overlap coefficients, such as DICE, the radiologist detected deviations in the segmented muscle border and determined whether the result would impact the ability to accurately determine the volume of fibroglandular tissue and detection of breast lesions. Results: According to the radiologist’s scores, 95.5% of the slices did not mask breast tissue in such way that it could affect detection of breast lesions or volume measurements. In 13.1% of the slices a deviation in the segmented muscle border was present which would not impact breast lesion detection. In 70 datasets (78%) at least 95% of the slices were segmented in such a way it would not affect detection of breast lesions, and in 60 (66%) datasets this was 100%. Conclusion: Dynamic programming with dedicated heuristics shows promising potential to segment the pectoral muscle in women with dense breasts.« less

Development and proof-of-concept of three-dimensional lung histology volumes

NASA Astrophysics Data System (ADS)

Mathew, Lindsay; Alabousi, Mostafa; Wheatley, Andrew; Aladl, Usaf; Slipetz, Deborah; Hogg, James C.; Fenster, Aaron; Parraga, Grace

2012-03-01

Most medical imaging is inherently three-dimensional (3D) but for validation of pathological findings, histopathology is commonly used and typically histopathology images are acquired as twodimensional slices with quantitative analysis performed in a single dimension. Histopathology is invasive, labour-intensive, and the analysis cannot be performed in real time, yet it remains the gold standard for the pathological diagnosis and validation of clinical or radiological diagnoses of disease. A major goal worldwide is to improve medical imaging resolution, sensitivity and specificity to better guide therapy and biopsy and to one day delay or replace biopsy. A key limitation however is the lack of tools to directly compare 3D macroscopic imaging acquired in patients with histopathology findings, typically provided in a single dimension (1D) or in two dimensions (2D). To directly address this, we developed methods for 2D histology slice visualization/registration to generate 3D volumes and quantified tissue components in the 3D volume for direct comparison to volumetric micro-CT and clinical CT. We used the elastase-instilled mouse emphysema lung model to evaluate our methods with murine lungs sectioned (5 μm thickness/10 μm gap) and digitized with 2μm in-plane resolution. 3D volumes were generated for wildtype and elastase mouse lung sections after semi-automated registration of all tissue slices. The 1D mean linear intercept (Lm) for wildtype (WT) (47.1 μm +/- 9.8 μm) and elastase mouse lung (64.5 μm +/- 14.0 μm) was significantly different (p<.001). We also generated 3D measurements based on tissue and airspace morphometry from the 3D volumes and all of these were significantly different (p<.0001) when comparing elastase and WT mouse lung. The ratio of the airspace-to-lung volume for the entire lung volume was also significantly and strongly correlated with Lm.

Murine precision-cut liver slices (PCLS): a new tool for studying tumor microenvironments and cell signaling ex vivo.

PubMed

Koch, Alexandra; Saran, Shashank; Tran, Doan Duy Hai; Klebba-Färber, Sabine; Thiesler, Hauke; Sewald, Katherina; Schindler, Susann; Braun, Armin; Klopfleisch, Robert; Tamura, Teruko

2014-11-07

One of the most insidious characteristics of cancer is its spread to and ability to compromise distant organs via the complex process of metastasis. Communication between cancer cells and organ-resident cells via cytokines/chemokines and direct cell-cell contacts are key steps for survival, proliferation and invasion of metastasized cancer cells in organs. Precision-cut liver slices (PCLS) are considered to closely reflect the in vivo situation and are potentially useful for studying the interaction of cancer cells with liver-resident cells as well as being a potentially useful tool for screening anti-cancer reagents. Application of the PCLS technique in the field of cancer research however, has not yet been well developed. We established the mouse PCLS system using perfluorodecalin (PFD) as an artificial oxygen carrier. Using this system we show that the adherence of green fluorescent protein (GFP) labeled MDA-MB-231 (highly invasive) cells to liver tissue in the PCLS was 5-fold greater than that of SK-BR-3 (less invasive) cells. In addition, we generated PCLS from THOC5, a member of transcription/export complex (TREX), knockout (KO) mice. The PCLS still expressed Gapdh or Albumin mRNAs at normal levels, while several chemokine/growth factor or metalloprotease genes, such as Cxcl12, Pdgfa, Tgfb, Wnt11, and Mmp1a genes were downregulated more than 2-fold. Interestingly, adhesion of cancer cells to THOC5 KO liver slices was far less (greater than 80% reduction) than to wild-type liver slices. Mouse PCLS cultures in the presence of PFD may serve as a useful tool for screening local adherence and invasiveness of individual cancer cells, since single cells can be observed. This method may also prove useful for identification of genes in liver-resident cells that support cancer invasion by using PCLS from transgenic liver.

Comparative evaluation of the amount of gingival displacement produced by three different gingival retraction systems: An in vivo study.

PubMed

Chaudhari, Jignesh; Prajapati, Paranjay; Patel, Jayanti; Sethuraman, Rajesh; Naveen, Y G

2015-01-01

Tetrahydrozoline has been introduced as new gingival retraction agent but its clinical efficacy with widely used conventional retraction agents has not been tested. The study was designed to clinically evaluate efficacy of newer retraction agent tetrahydrozoline with two widely used retraction systems i.e., Expasyl retraction system and medicated retraction cords on basis of amount of gingival retraction. 30 subjects were selected according to inclusion and exclusion criteria. Maxillary Impressions were made with irreversible hydrocolloid for all subjects. Tray material was used for making the special tray. Latin Block Design was Used in the Study to avoid tissue fatigue. Retraction was done with aluminium chloride; Tetrahydrozoline and Expasyl according to Latin block design. Impressions were poured with die stone. Casts were retrieved and sections were made with die cutter. 3 mm thin slices were obtained. Each slice was used to measure the amount of retraction under stereomicroscope under 20x and images were transferred to image analyser. The amount of gingival retraction obtained by using aluminium chloride as gingival retraction agent was maximum (148238.33 μm(2)) compared to tetrahydrozoline (140737.87 μm(2)) and Expasyl (67784.90 μm(2)).

Metabolic Characterization of Acutely Isolated Hippocampal and Cerebral Cortical Slices Using [U-13C]Glucose and [1,2-13C]Acetate as Substrates.

PubMed

McNair, Laura F; Kornfelt, Rasmus; Walls, Anne B; Andersen, Jens V; Aldana, Blanca I; Nissen, Jakob D; Schousboe, Arne; Waagepetersen, Helle S

2017-03-01

Brain slice preparations from rats, mice and guinea pigs have served as important tools for studies of neurotransmission and metabolism. While hippocampal slices routinely have been used for electrophysiology studies, metabolic processes have mostly been studied in cerebral cortical slices. Few comparative characterization studies exist for acute hippocampal and cerebral cortical slices, hence, the aim of the current study was to characterize and compare glucose and acetate metabolism in these slice preparations in a newly established incubation design. Cerebral cortical and hippocampal slices prepared from 16 to 18-week-old mice were incubated for 15-90 min with unlabeled glucose in combination with [U- 13 C]glucose or [1,2- 13 C]acetate. Our newly developed incubation apparatus allows accurate control of temperature and is designed to avoid evaporation of the incubation medium. Subsequent to incubation, slices were extracted and extracts analyzed for 13 C-labeling (%) and total amino acid contents (µmol/mg protein) using gas chromatography-mass spectrometry and high performance liquid chromatography, respectively. Release of lactate from the slices was quantified by analysis of the incubation media. Based on the measured 13 C-labeling (%), total amino acid contents and relative activity of metabolic enzymes/pathways, we conclude that the slice preparations in the current incubation apparatus exhibited a high degree of metabolic integrity. Comparison of 13 C-labeling observed with [U- 13 C]glucose in slices from cerebral cortex and hippocampus revealed no significant regional differences regarding glycolytic or total TCA cycle activities. On the contrary, results from the incubations with [1,2- 13 C]acetate suggest a higher capacity of the astrocytic TCA cycle in hippocampus compared to cerebral cortex. Finally, we propose a new approach for assessing compartmentation of metabolite pools between astrocytes and neurons using 13 C-labeling (%) data obtained from mass spectrometry. Based on this approach we suggest that cellular metabolic compartmentation in hippocampus and cerebral cortex is very similar.

Estimating the number and size of phloem sieve plate pores using longitudinal views and geometric reconstruction.

PubMed

Bussières, Philippe

2014-05-12

Because it is difficult to obtain transverse views of the plant phloem sieve plate pores, which are short tubes, to estimate their number and diameters, a method based on longitudinal views is proposed. This method uses recent methods to estimate the number and the sizes of approximately circular objects from their images, given by slices perpendicular to the objects. Moreover, because such longitudinal views are obtained from slices that are rather close to the plate centres whereas the pore size may vary with the pore distance from the plate edge, a sieve plate reconstruction model was developed and incorporated in the method to consider this bias. The method was successfully tested with published longitudinal views of phloem of Soybean and an exceptional entire transverse view from the same tissue. The method was also validated with simulated slices in two sieve plates from Cucurbita and Phaseolus. This method will likely be useful to estimate and to model the hydraulic conductivity and the architecture of the plant phloem, and it could have applications for other materials with approximately cylindrical structures.

Effect of α-p-chlorophenoxyisobutyrate on the metabolism of isoprenoid compounds in the rat

PubMed Central

Krishnaiah, K. V.; Ramasarma, T.

1970-01-01

1. Feeding of α-p-chlorophenoxyisobutyrate (CPIB) to rats increased ubiquinone concentration in the liver but not in other tissues. The increase was progressive with the time of feeding and related to the concentration of CPIB in the diet. 2. Incorporation of [1-14C]acetate, but not of [2-14C]mevalonate, into sterols in the liver in vivo or by liver slices in vitro was decreased on feeding the rats with CPIB. However, incorporation of mevalonate into ubiquinone increased. 3. CPIB, when added in low concentrations to liver slices, had no effect on isoprene synthesis from acetate; higher concentrations, however, were inhibitory. 4. No activation of ubiquinone synthesis from mevalonate was observed when CPIB was added to the liver slices synthesizing ubiquinone. 5. The increase in ubiquinone in CPIB-fed animals appears to be due to increased synthesis in the initial stages and to decreased catabolism in the later stages. 6. An inverse relationship was found between the concentration of ubiquinone in the liver and the serum sterol concentration in CPIB-fed rats. PMID:5435680

Confocal quantification of cis-regulatory reporter gene expression in living sea urchin.

PubMed

Damle, Sagar; Hanser, Bridget; Davidson, Eric H; Fraser, Scott E

2006-11-15

Quantification of GFP reporter gene expression at single cell level in living sea urchin embryos can now be accomplished by a new method of confocal laser scanning microscopy (CLSM). Eggs injected with a tissue-specific GFP reporter DNA construct were grown to gastrula stage and their fluorescence recorded as a series of contiguous Z-section slices that spanned the entire embryo. To measure the depth-dependent signal decay seen in the successive slices of an image stack, the eggs were coinjected with a freely diffusible internal fluorescent standard, rhodamine dextran. The measured rhodamine fluorescence was used to generate a computational correction for the depth-dependent loss of GFP fluorescence per slice. The intensity of GFP fluorescence was converted to the number of GFP molecules using a conversion constant derived from CLSM imaging of eggs injected with a measured quantity of GFP protein. The outcome is a validated method for accurately counting GFP molecules in given cells in reporter gene transfer experiments, as we demonstrate by use of an expression construct expressed exclusively in skeletogenic cells.

Histopathological Analysis of PEEK Wear Particle Effects on the Synovial Tissue of Patients

PubMed Central

Jansson, V.; Giurea, A.

2016-01-01

Introduction. Increasing interest developed in the use of carbon-fiber-reinforced-poly-ether-ether-ketones (CFR-PEEK) as an alternative bearing material in knee arthroplasty. The effects of CFR-PEEK wear in in vitro and animal studies are controversially discussed, as there are no data available concerning human tissue. The aim of this study was to analyze human tissue containing CFR-PEEK as well as UHMWPE wear debris. The authors hypothesized no difference between the used biomaterials. Methods and Materials. In 10 patients during knee revision surgery of a rotating-hinge-knee-implant-design, synovial tissue samples were achieved (tibial inserts: UHMWPE; bushings and flanges: CFR-PEEK). One additional patient received revision surgery without any PEEK components as a control. The tissue was paraffin-embedded, sliced into 2 μm thick sections, and stained with hematoxylin and eosin in a standard process. A modified panoptical staining was also done. Results. A “wear-type” reaction was seen in the testing and the control group. In all samples, the UHMWPE particles were scattered in the tissue or incorporated in giant cells. CFR-PEEK particles were seen as conglomerates and only could be found next to vessels. CFR-PEEK particles showed no giant-cell reactions. In conclusion, the hypothesis has to be rejected. UHMWPE and PEEK showed a different scatter-behavior in human synovial tissue. PMID:27766256

Multidisciplinary research program directed toward utilization of solar energy through bioconversion of renewable resources

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

Not Available

1980-07-01

Progress is reported in this multidisciplinary research program. Genetic selection of superior trees, physiological basis of vigor, tissue culture systems leading to cloning of diploid and haploid cell lines are discussed in the Program A report. The physiological basis of enhanced oleoresin formation in southern pines when treated with sublethal concentrations of the herbicide paraquat was investigated in Program B. In Program C, metabolic changes in the stems of slash pine, in vivo, after application with paraquat were determined. The use of phdoem and xylem tissue slices as a laboratory model for studying paraquat associated- and normal-terpene synthesis in pinesmore » is discussed. The biochemistry and physiology of methane formation from cellulose during anaerobic fermentation are discussed in the Program D report. (DMC)« less

Phase contrast MR angiography techniques.

PubMed

Dumoulin, C L

1995-08-01

Phase contrast MR methods encode information from macroscopic motion into the phase of the MR signal. Phase contrast methods can be applied with small and large fields-of-view, can give quantitative measures of velocity, and provide excellent suppression of signals from stationary tissue. Unlike time-of-flight methods, phase contrast methods directly measure flow and thus are not hindered by the artifactual appearance of tissue having short T1. Phase contrast angiograms can be two-dimensional (thin slice or projectile), three-dimensional, and/or time resolved and have applications throughout the body.

Visible Human 2.0--the next generation.

PubMed

Ratiu, Peter; Hillen, Berend; Glaser, Jack; Jenkins, Donald P

2003-01-01

The National Library of Medicine has initiated the development of new anatomical methods and techniques for the acquisition of higher resolution data sets, aiming to address the anatomical artifacts encountered in the development of the Visible Human Male and Female and to insure enhanced detection of structures, providing data in greater depth and breadth. Given this framework, we acquired a complete data set of the head and neck. CT and MR scans were also obtained with registration hardware inserted prior to imaging. The arterial and venous systems were injected with colorized araldite-F. After freezing, axial cryosectioning and digital photography at 147 microns/voxel resolution was performed. Two slabs of the specimen were acquired with a special tissue harvesting technique. The resulting tissue slices of the whole specimen were stained for different tissue types. The resulting histological material was then scanned at a 60x magnification using the Virtual Slice technology at 2 microns/pixel resolution (each slide approximately 75,000 x 100,000 pixels). In this data set, for the first time anatomy is presented as a continuum from a radiologic granularity of 1 mm/voxel, to a macroscopic resolution of .147 mm/voxel, to microscopic resolution of 2 microns/pixel. The hiatus between gross anatomy and histology has been assumed insurmountable, and until the present time this gap was bridged by extrapolating findings on minute samples. The availability of anatomical data with the fidelity presented will render it possible to perform a seamless study of whole organs at a cellular level and provide a testbed for the validation of histological estimation techniques. A future complete Visible Human created from data acquired at a cellular resolution, aside from its daunting size, will open new possibilities in multiple directions in medical research and simulation.

Healthy food consumption in young women. The influence of others' eating behavior and body weight appearance.

PubMed

Stel, Mariëlle; van Koningsbruggen, Guido M

2015-07-01

People's eating behaviors tend to be influenced by the behaviors of others. In the present studies, we investigated the effect of another person's eating behavior and body weight appearance on healthy food consumption of young women. In Study 1, participants watched a short film fragment together with a confederate who appeared normal weight or overweight and consumed either 3 or 10 cucumber slices. In Study 2, a confederate who appeared underweight, normal weight, or overweight consumed no or 4 cucumber slices. The number of cucumber slices eaten by participants was registered. Results showed that participants' healthy eating behavior was influenced by the confederate's eating behavior when the confederate was underweight, normal weight, and overweight. Participants ate more cucumber slices when the confederate ate a higher amount of cucumber slices compared with a lower (or no) amount of cucumber slices (Studies 1 and 2). The food intake effect was stronger for the underweight compared with the overweight model (Study 2). Copyright © 2015 Elsevier Ltd. All rights reserved.

A Systematic Evaluation of Collagen Crosslinks in the Human Cervix

PubMed Central

Zork, Noelia M; Myers, Kristin Marie; Yoshida, Ms. Kyoko; Cremers, Serge; Jiang, Hongfeng; Ananth, Cande V; Wapner, Ronald; Kitajewski, Jan; Vink, Joy

2014-01-01

Objective The mechanical strength of the cervix relies on crosslinking of the tissue’s collagen network. Clinically, the internal os is functionally distinct from the external os. We sought to detect specific collagen crosslinks in human cervical tissue and determine if crosslink profiles were similar at the internal and external os. Study Design Transverse slices of cervical tissue were obtained at the internal and external os from 13 non-pregnant, premenopausal women undergoing a benign hysterectomy. To understand how crosslinks were distributed throughout the entire cervix and at the internal and external os, biopsies were obtained from three circumferential zones in four quadrants from each slice. Biopsies were pulverized, lyophilized, reduced with sodium borohydride, hydrolyzed with hydrochloric acid and reconstituted in heptafluorobutyric acid buffer. Hydroxyproline was measured by ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS), converted to total collagen, and normalized by dry weight. Collagen crosslinks pyridinoline (PYD), deoxypyridinoline (DPD), dihydroxylysinonorleucine (DHLNL), and the nonenzymatic advanced glycation end product pentosidine [PEN] were measured by UPLC-ESI-MS/MS and reported as crosslink density ratio (crosslink:total collagen). Generalized estimated equation analysis was used to compare results between the internal and external os and to compare quadrants and zones within slices from the internal and external os to determine if crosslink profiles were similar. Results 592 samples from 13 patients were analyzed. Collagen crosslinks are detectable in the human cervix by UPLC-ESI-MS/MS. When comparing all samples from the internal and external os, similar levels of collagen content, PYD, DHLNL and DPD were found but PEN density was higher at the external os (0.005 vs 0.004, P=0.001). When comparing all internal os samples, significant heterogeneity was found in collagen content and crosslink densities across zones and quadrants. The external os exhibited heterogeneity only across zones. Conclusion Collagen crosslinks (PYD, DPD, DHLNL, and PEN) are detectable by UPLC-ESI-MS/MS in the human cervix. The internal os exhibits significant collagen crosslink heterogeneity compared to the external os. Further studies are needed to evaluate how collagen crosslink heterogeneity correlates to the mechanical strength and function of the human cervix. PMID:25281365

Objective evaluation of linear and nonlinear tomosynthetic reconstruction algorithms

NASA Astrophysics Data System (ADS)

Webber, Richard L.; Hemler, Paul F.; Lavery, John E.

2000-04-01

This investigation objectively tests five different tomosynthetic reconstruction methods involving three different digital sensors, each used in a different radiologic application: chest, breast, and pelvis, respectively. The common task was to simulate a specific representative projection for each application by summation of appropriately shifted tomosynthetically generated slices produced by using the five algorithms. These algorithms were, respectively, (1) conventional back projection, (2) iteratively deconvoluted back projection, (3) a nonlinear algorithm similar to back projection, except that the minimum value from all of the component projections for each pixel is computed instead of the average value, (4) a similar algorithm wherein the maximum value was computed instead of the minimum value, and (5) the same type of algorithm except that the median value was computed. Using these five algorithms, we obtained data from each sensor-tissue combination, yielding three factorially distributed series of contiguous tomosynthetic slices. The respective slice stacks then were aligned orthogonally and averaged to yield an approximation of a single orthogonal projection radiograph of the complete (unsliced) tissue thickness. Resulting images were histogram equalized, and actual projection control images were subtracted from their tomosynthetically synthesized counterparts. Standard deviations of the resulting histograms were recorded as inverse figures of merit (FOMs). Visual rankings of image differences by five human observers of a subset (breast data only) also were performed to determine whether their subjective observations correlated with homologous FOMs. Nonparametric statistical analysis of these data demonstrated significant differences (P > 0.05) between reconstruction algorithms. The nonlinear minimization reconstruction method nearly always outperformed the other methods tested. Observer rankings were similar to those measured objectively.

Interactive lung segmentation in abnormal human and animal chest CT scans

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

Kockelkorn, Thessa T. J. P., E-mail: thessa@isi.uu.nl; Viergever, Max A.; Schaefer-Prokop, Cornelia M.

2014-08-15

Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling resultsmore » can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in challenging chest CT images. Both systems do not require prior knowledge of the scans under consideration and work on a variety of scans.« less

Evidence of neurofibromatosis type 1 in a multi-morbid Inca child mummy: A paleoradiological investigation using computed tomography

PubMed Central

Wittig, Holger; Zesch, Stephanie; Rosendahl, Wilfried; Blache, Sandra; Müller-Gerbl, Magdalena; Hotz, Gerhard

2017-01-01

Objective In this study, an Inca bundle was examined using computed tomography (CT). The primary aim was to determine the preservation status of bony and soft tissues, the sex, the age at the time of death, possible indicators for disease or even the cause of death, as well as the kind of mummification. A secondary aim was to obtain a brief overview of the wrapping in order to gain additional information on the cultural background. Materials and methods The bundle belongs to the Museum of Cultures in Basel, Switzerland, and was bought in Munich, Germany, in 1921. Radiocarbon dating of the superficial textile yielded a calibrated age between 1480 and 1650 AD. The mummy was investigated using multi-slice CT with slice thickness of 0.75 mm and 110 kilovolt. For standardized assessment of soft tissue preservation, a recently developed checklist was applied. Results CT revealed the mummy of a seven to nine year old boy with superior preservation of bony and soft tissues allowing detailed assessment. Indicators of neurofibromatosis type 1 (paravertebral and cutaneous neurofibromas, a breast neurofibroma, sphenoid wing dysplasia), Chagas disease (dilatation of the esophagus, stomach, rectum, and large amounts of feces), and lung infection (pleural adherence, calcifications), probably due to tuberculosis, were found. Furthermore, signs of peri-mortem violence (transection of the chest and a defect in the abdominal wall) were detected. CT images revealed a carefully performed wrapping. Conclusion CT examination of the Inca bundle proved to be an important non-destructive examination method. Standardized assessment, especially of the soft tissue structures, allowed for diagnoses of several diseases, indicating a multi-morbid child at the time of death. The careful wrapping pointed to a ceremonial burial. Within the cultural background, the signs of fatal violence were discussed as a possible result of war, murder, accident, or human sacrifice. PMID:28403237

Simultaneous orthogonal plane imaging.

PubMed

Mickevicius, Nikolai J; Paulson, Eric S

2017-11-01

Intrafraction motion can result in a smearing of planned external beam radiation therapy dose distributions, resulting in an uncertainty in dose actually deposited in tissue. The purpose of this paper is to present a pulse sequence that is capable of imaging a moving target at a high frame rate in two orthogonal planes simultaneously for MR-guided radiotherapy. By balancing the zero gradient moment on all axes, slices in two orthogonal planes may be spatially encoded simultaneously. The orthogonal slice groups may be acquired with equal or nonequal echo times. A Cartesian spoiled gradient echo simultaneous orthogonal plane imaging (SOPI) sequence was tested in phantom and in vivo. Multiplexed SOPI acquisitions were performed in which two parallel slices were imaged along two orthogonal axes simultaneously. An autocalibrating phase-constrained 2D-SENSE-GRAPPA (generalized autocalibrating partially parallel acquisition) algorithm was implemented to reconstruct the multiplexed data. SOPI images without intraslice motion artifacts were reconstructed at a maximum frame rate of 8.16 Hz. The 2D-SENSE-GRAPPA reconstruction separated the parallel slices aliased along each orthogonal axis. The high spatiotemporal resolution provided by SOPI has the potential to be beneficial for intrafraction motion management during MR-guided radiation therapy or other MRI-guided interventions. Magn Reson Med 78:1700-1710, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Feature tracking for automated volume of interest stabilization on 4D-OCT images

NASA Astrophysics Data System (ADS)

Laves, Max-Heinrich; Schoob, Andreas; Kahrs, Lüder A.; Pfeiffer, Tom; Huber, Robert; Ortmaier, Tobias

2017-03-01

A common representation of volumetric medical image data is the triplanar view (TV), in which the surgeon manually selects slices showing the anatomical structure of interest. In addition to common medical imaging such as MRI or computed tomography, recent advances in the field of optical coherence tomography (OCT) have enabled live processing and volumetric rendering of four-dimensional images of the human body. Due to the region of interest undergoing motion, it is challenging for the surgeon to simultaneously keep track of an object by continuously adjusting the TV to desired slices. To select these slices in subsequent frames automatically, it is necessary to track movements of the volume of interest (VOI). This has not been addressed with respect to 4DOCT images yet. Therefore, this paper evaluates motion tracking by applying state-of-the-art tracking schemes on maximum intensity projections (MIP) of 4D-OCT images. Estimated VOI location is used to conveniently show corresponding slices and to improve the MIPs by calculating thin-slab MIPs. Tracking performances are evaluated on an in-vivo sequence of human skin, captured at 26 volumes per second. Among investigated tracking schemes, our recently presented tracking scheme for soft tissue motion provides highest accuracy with an error of under 2.2 voxels for the first 80 volumes. Object tracking on 4D-OCT images enables its use for sub-epithelial tracking of microvessels for image-guidance.

Confocal Microscopy and Molecular-Specific Optical Contrast Agents for the Detection of Oral Neoplasia

PubMed Central

Carlson, Alicia L.; Gillenwater, Ann M.; Williams, Michelle D.; El-Naggar, Adel K.; Richards-Kortum, R. R.

2009-01-01

Using current clinical diagnostic techniques, it is difficult to visualize tumor morphology and architecture at the cellular level, which is necessary for diagnostic localization of pathologic lesions. Optical imaging techniques have the potential to address this clinical need by providing real-time, sub-cellular resolution images. This paper describes the use of dual mode confocal microscopy and optical molecular-specific contrast agents to image tissue architecture, cellular morphology, and sub-cellular molecular features of normal and neoplastic oral tissues. Fresh tissue slices were prepared from 33 biopsies of clinically normal and abnormal oral mucosa obtained from 14 patients. Reflectance confocal images were acquired after the application of 6% acetic acid, and fluorescence confocal images were acquired after the application of a fluorescence contrast agent targeting the epidermal growth factor receptor (EGFR). The dual imaging modes provided images similar to light microscopy of hematoxylin and eosin and immunohistochemistry staining, but from thick fresh tissue slices. Reflectance images provided information on the architecture of the tissue and the cellular morphology. The nuclear-to-cytoplasmic (N/C) ratio from the reflectance images was at least 7.5 times greater for the carcinoma than the corresponding normal samples, except for one case of highly keratinized carcinoma. Separation of carcinoma from normal and mild dysplasia was achieved using this ratio (p<0.01). Fluorescence images of EGFR expression yielded a mean fluorescence labeling intensity (FLI) that was at least 2.7 times higher for severe dysplasia and carcinoma samples than for the corresponding normal sample, and could be used to distinguish carcinoma from normal and mild dysplasia (p<0.01). Analyzed together, the N/C ratio and the mean FLI may improve the ability to distinguish carcinoma from normal squamous epithelium. PMID:17877424

Thyroid organotypic rat and human cultures used to investigate drug effects on thyroid function, hormone synthesis and release pathways

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

Vickers, Alison E.M., E-mail: vickers_alison@allergan.com; Heale, Jason; Sinclair, John R.

Drug induced thyroid effects were evaluated in organotypic models utilizing either a rat thyroid lobe or human thyroid slices to compare rodent and human response. An inhibition of thyroid peroxidase (TPO) function led to a perturbation in the expression of key genes in thyroid hormone synthesis and release pathways. The clinically used thiourea drugs, methimazole (MMI) and 6-n-propyl-2-thioruacil (PTU), were used to evaluate thyroid drug response in these models. Inhibition of TPO occurred early as shown in rat thyroid lobes (2 h) and was sustained in both rat (24–48 h) and human (24 h) with ≥ 10 μM MMI. Thyroidmore » from rats treated with single doses of MMI (30–1000 mg/kg) exhibited sustained TPO inhibition at 48 h. The MMI in vivo thyroid concentrations were comparable to the culture concentrations (∼ 15–84 μM), thus demonstrating a close correlation between in vivo and ex vivo thyroid effects. A compensatory response to TPO inhibition was demonstrated in the rat thyroid lobe with significant up-regulation of genes involved in the pathway of thyroid hormone synthesis (Tpo, Dio1, Slc5a5, Tg, Tshr) and the megalin release pathway (Lrp2) by 24 h with MMI (≥ 10 μM) and PTU (100 μM). Similarly, thyroid from the rat in vivo study exhibited an up-regulation of Dio1, Slc5a5, Lrp2, and Tshr. In human thyroid slices, there were few gene expression changes (Slc5a5, ∼ 2-fold) and only at higher MMI concentrations (≥ 1500 μM, 24 h). Extended exposure (48 h) resulted in up-regulation of Tpo, Dio1 and Lrp2, along with Slc5a5 and Tshr. In summary, TPO was inhibited by similar MMI concentrations in rat and human tissue, however an increased sensitivity to drug treatment in rat is indicated by the up-regulation of thyroid hormone synthesis and release gene pathways at concentrations found not to affect human tissue. -- Highlights: ► Novel model of rat thyroid or human thyroid slices to evaluate pathways of injury. ► TPO inhibition by MMI or PTU altered hormone synthesis and release genes. ► Rat thyroid was more sensitive to the drug effects than human tissue.« less

Automated Quantification of Myocardial Salvage in a Rat Model of Ischemia–Reperfusion Injury Using 3D High‐Resolution Magnetic Resonance Imaging (MRI)

PubMed Central

Grieve, Stuart M.; Mazhar, Jawad; Callaghan, Fraser; Kok, Cindy Y.; Tandy, Sarah; Bhindi, Ravinay; Figtree, Gemma A.

2014-01-01

Background Quantification of myocardial “area at risk” (AAR) and myocardial infarction (MI) zone is critical for assessing novel therapies targeting myocardial ischemia–reperfusion (IR) injury. Current “gold‐standard” methods perfuse the heart with Evan's Blue and stain with triphenyl tetrazolium chloride (TTC), requiring manual slicing and analysis. We aimed to develop and validate a high‐resolution 3‐dimensional (3D) magnetic resonance imaging (MRI) method for quantifying MI and AAR. Methods and Results Forty‐eight hours after IR was induced, rats were anesthetized and gadopentetate dimeglumine was administered intravenously. After 10 minutes, the coronary artery was re‐ligated and a solution containing iron oxide microparticles and Evan's Blue was infused (for comparison). Hearts were harvested and transversally sectioned for TTC staining. Ex vivo MR images of slices were acquired on a 9.4‐T magnet. T2* data allowed visualization of AAR, with microparticle‐associated signal loss in perfused regions. T1 data demonstrated gadolinium retention in infarcted zones. Close correlation (r=0.92 to 0.94; P<0.05) of MRI and Evan's Blue/TTC measures for both AAR and MI was observed when the combined techniques were applied to the same heart slice. However, 3D MRI acquisition and analysis of whole heart reduced intra‐observer variability compared to assessment of isolated slices, and allowed automated segmentation and analysis, thus reducing interobserver variation. Anatomical resolution of 81 μm3 was achieved (versus ≈2 mm with manual slicing). Conclusions This novel, yet simple, MRI technique allows precise assessment of infarct and AAR zones. It removes the need for tissue slicing and provides opportunity for 3D digital analysis at high anatomical resolution in a streamlined manner accessible for all laboratories already performing IR experiments. PMID:25146703

Thick Slice and Thin Slice Teaching Evaluations

ERIC Educational Resources Information Center

Tom, Gail; Tong, Stephanie Tom; Hesse, Charles

2010-01-01

Student-based teaching evaluations are an integral component to institutions of higher education. Previous work on student-based teaching evaluations suggest that evaluations of instructors based upon "thin slice" 30-s video clips of them in the classroom correlate strongly with their end of the term "thick slice" student evaluations. This study's…

Histology-validated x-ray tomography for imaging human coronary arteries

NASA Astrophysics Data System (ADS)

Buscema, Marzia; Schulz, Georg; Deyhle, Hans; Khimchenko, Anna; Matviykiv, Sofiya; Holme, Margaret N.; Hipp, Alexander; Beckmann, Felix; Saxer, Till; Michaud, Katarzyna; Müller, Bert

2016-10-01

Heart disease is the number one cause of death worldwide. To improve therapy and patient outcome, the knowledge of anatomical changes in terms of lumen morphology and tissue composition of constricted arteries is crucial for designing a localized drug delivery to treat atherosclerosis disease. Traditional tissue characterization by histology is a pivotal tool, although it brings disadvantages such as vessel morphology modification during decalcification and slicing. X-ray tomography in absorption and phase contrast modes yields a deep understanding in blood vessel anatomy in healthy and diseased stages: measurements in absorption mode make visible highly absorbing tissue components including cholesterol plaques, whereas phase contrast tomography gains better contrast of the soft tissue components such as vessel walls. Established synchrotron radiation-based micro-CT techniques ensure high performance in terms of 3D visualization of highly absorbing and soft tissues.

The topology of large-scale structure. VI - Slices of the universe

NASA Astrophysics Data System (ADS)

Park, Changbom; Gott, J. R., III; Melott, Adrian L.; Karachentsev, I. D.

1992-03-01

Results of an investigation of the topology of large-scale structure in two observed slices of the universe are presented. Both slices pass through the Coma cluster and their depths are 100 and 230/h Mpc. The present topology study shows that the largest void in the CfA slice is divided into two smaller voids by a statistically significant line of galaxies. The topology of toy models like the white noise and bubble models is shown to be inconsistent with that of the observed slices. A large N-body simulation was made of the biased cloud dark matter model and the slices are simulated by matching them in selection functions and boundary conditions. The genus curves for these simulated slices are spongelike and have a small shift in the direction of a meatball topology like those of observed slices.

The topology of large-scale structure. VI - Slices of the universe

NASA Technical Reports Server (NTRS)

Park, Changbom; Gott, J. R., III; Melott, Adrian L.; Karachentsev, I. D.

1992-01-01

Results of an investigation of the topology of large-scale structure in two observed slices of the universe are presented. Both slices pass through the Coma cluster and their depths are 100 and 230/h Mpc. The present topology study shows that the largest void in the CfA slice is divided into two smaller voids by a statistically significant line of galaxies. The topology of toy models like the white noise and bubble models is shown to be inconsistent with that of the observed slices. A large N-body simulation was made of the biased cloud dark matter model and the slices are simulated by matching them in selection functions and boundary conditions. The genus curves for these simulated slices are spongelike and have a small shift in the direction of a meatball topology like those of observed slices.

The mouse cerebellar cortex in organotypic slice cultures: an in vitro model to analyze the consequences of mutations and pathologies on neuronal survival, development, and function.

PubMed

Lonchamp, Etienne; Dupont, Jean-Luc; Beekenkamp, Huguette; Poulain, Bernard; Bossu, Jean-Louis

2006-01-01

Thin acute slices and dissociated cell cultures taken from different parts of the brain have been widely used to examine the function of the nervous system, neuron-specific interactions, and neuronal development (specifically, neurobiology, neuropharmacology, and neurotoxicology studies). Here, we focus on an alternative in vitro model: brain-slice cultures in roller tubes, initially introduced by Beat Gähwiler for studies with rats, that we have recently adapted for studies of mouse cerebellum. Cultured cerebellar slices afford many of the advantages of dissociated cultures of neurons and thin acute slices. Organotypic slice cultures were established from newborn or 10-15-day-old mice. After 3-4 weeks in culture, the slices flattened to form a cell monolayer. The main types of cerebellar neurons could be identified with immunostaining techniques, while their electrophysiological properties could be easily characterized with the patch-clamp recording technique. When slices were taken from newborn mice and cultured for 3 weeks, aspects of the cerebellar development were displayed. A functional neuronal network was established despite the absence of mossy and climbing fibers, which are the two excitatory afferent projections to the cerebellum. When slices were made from 10-15-day-old mice, which are at a developmental stage when cerebellum organization is almost established, the structure and neuronal pathways were intact after 3-4 weeks in culture. These unique characteristics make organotypic slice cultures of mouse cerebellar cortex a valuable model for analyzing the consequences of gene mutations that profoundly alter neuronal function and compromise postnatal survival.

3D segmentation of kidney tumors from freehand 2D ultrasound

NASA Astrophysics Data System (ADS)

Ahmad, Anis; Cool, Derek; Chew, Ben H.; Pautler, Stephen E.; Peters, Terry M.

2006-03-01

To completely remove a tumor from a diseased kidney, while minimizing the resection of healthy tissue, the surgeon must be able to accurately determine its location, size and shape. Currently, the surgeon mentally estimates these parameters by examining pre-operative Computed Tomography (CT) images of the patient's anatomy. However, these images do not reflect the state of the abdomen or organ during surgery. Furthermore, these images can be difficult to place in proper clinical context. We propose using Ultrasound (US) to acquire images of the tumor and the surrounding tissues in real-time, then segmenting these US images to present the tumor as a three dimensional (3D) surface. Given the common use of laparoscopic procedures that inhibit the range of motion of the operator, we propose segmenting arbitrarily placed and oriented US slices individually using a tracked US probe. Given the known location and orientation of the US probe, we can assign 3D coordinates to the segmented slices and use them as input to a 3D surface reconstruction algorithm. We have implemented two approaches for 3D segmentation from freehand 2D ultrasound. Each approach was evaluated on a tissue-mimicking phantom of a kidney tumor. The performance of our approach was determined by measuring RMS surface error between the segmentation and the known gold standard and was found to be below 0.8 mm.

MO-F-CAMPUS-J-04: Tissue Segmentation-Based MR Electron Density Mapping Method for MR-Only Radiation Treatment Planning of Brain

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

Yu, H; Lee, Y; Ruschin, M

2015-06-15

Purpose: Automatically derive electron density of tissues using MR images and generate a pseudo-CT for MR-only treatment planning of brain tumours. Methods: 20 stereotactic radiosurgery (SRS) patients’ T1-weighted MR images and CT images were retrospectively acquired. First, a semi-automated tissue segmentation algorithm was developed to differentiate tissues with similar MR intensities and large differences in electron densities. The method started with approximately 12 slices of manually contoured spatial regions containing sinuses and airways, then air, bone, brain, cerebrospinal fluid (CSF) and eyes were automatically segmented using edge detection and anatomical information including location, shape, tissue uniformity and relative intensity distribution.more » Next, soft tissues - muscle and fat were segmented based on their relative intensity histogram. Finally, intensities of voxels in each segmented tissue were mapped into their electron density range to generate pseudo-CT by linearly fitting their relative intensity histograms. Co-registered CT was used as a ground truth. The bone segmentations of pseudo-CT were compared with those of co-registered CT obtained by using a 300HU threshold. The average distances between voxels on external edges of the skull of pseudo-CT and CT in three axial, coronal and sagittal slices with the largest width of skull were calculated. The mean absolute electron density (in Hounsfield unit) difference of voxels in each segmented tissues was calculated. Results: The average of distances between voxels on external skull from pseudo-CT and CT were 0.6±1.1mm (mean±1SD). The mean absolute electron density differences for bone, brain, CSF, muscle and fat are 78±114 HU, and 21±8 HU, 14±29 HU, 57±37 HU, and 31±63 HU, respectively. Conclusion: The semi-automated MR electron density mapping technique was developed using T1-weighted MR images. The generated pseudo-CT is comparable to that of CT in terms of anatomical position of tissues and similarity of electron density assignment. This method can allow MR-only treatment planning.« less

Detecting thermal phase transitions in corneal stroma by fluorescence micro-imaging analysis

NASA Astrophysics Data System (ADS)

Matteini, P.; Rossi, F.; Ratto, F.; Bruno, I.; Nesi, P.; Pini, R.

2008-02-01

Thermal modifications induced in corneal stroma were investigated by the use of fluorescence microscopy. Freshly extracted porcine corneas were immersed for 5 minutes in a water bath at temperatures in the 35-90°C range and stored in formalin. The samples were then sliced in 200-μm-thick transversal sections and analyzed under a stereomicroscope to assess corneal shrinkage. Fluorescence images of the thermally treated corneal samples were acquired using a slow-scan cooled CCD camera, after staining the slices with Indocyanine Green (ICG) fluorescent dye which allowed to detect fluorescence signal from the whole tissue. All measurements were performed using an inverted epifluorescence microscope equipped with a mercury lamp. The thermally-induced modifications to the corneal specimens were evaluated by studying the grey level distribution in the fluorescence images. For each acquired image, Discrete Fourier Transform (DFT) and entropy analyses were performed. The spatial distribution of DFT absolute value indicated the spatial orientation of the lamellar planes, while entropy was used to study the image texture, correlated to the stromal structural transitions. As a result, it was possible to indicate a temperature threshold value (62°C) for high thermal damage, resulting in a disorganization of the lamellar planes and in full agreement with the measured temperature for corneal shrinkage onset. Analysis of the image entropy evidenced five strong modifications in stromal architecture at temperatures of ~45°C, 53°C, 57°C, 66°C, 75°C. The proposed procedure proved to be an effective micro-imaging method capable of detecting subtle changes in corneal tissue subjected to thermal treatment.

Quantification of biological tissue and construction of patient equivalent phantom (skull and chest) for infants (1-5 years old)

NASA Astrophysics Data System (ADS)

Alves, A. F.; Pina, D. R.; Bacchim Neto, F. A.; Ribeiro, S. M.; Miranda, J. R. A.

2014-03-01

Our main purpose in this study was to quantify biological tissue in computed tomography (CT) examinations with the aim of developing a skull and a chest patient equivalent phantom (PEP), both specific to infants, aged between 1 and 5 years old. This type of phantom is widely used in the development of optimization procedures for radiographic techniques, especially in computed radiography (CR) systems. In order to classify and quantify the biological tissue, we used a computational algorithm developed in Matlab ®. The algorithm performed a histogram of each CT slice followed by a Gaussian fitting of each tissue type. The algorithm determined the mean thickness for the biological tissues (bone, soft, fat, and lung) and also converted them into the corresponding thicknesses of the simulator material (aluminum, PMMA, and air). We retrospectively analyzed 148 CT examinations of infant patients, 56 for skull exams and 92 were for chest. The results provided sufficient data to construct a phantom to simulate the infant chest and skull in the posterior-anterior or anterior-posterior (PA/AP) view. Both patient equivalent phantoms developed in this study can be used to assess physical variables such as noise power spectrum (NPS) and signal to noise ratio (SNR) or perform dosimetric control specific to pediatric protocols.

Slice sampling technique in Bayesian extreme of gold price modelling

NASA Astrophysics Data System (ADS)

Rostami, Mohammad; Adam, Mohd Bakri; Ibrahim, Noor Akma; Yahya, Mohamed Hisham

2013-09-01

In this paper, a simulation study of Bayesian extreme values by using Markov Chain Monte Carlo via slice sampling algorithm is implemented. We compared the accuracy of slice sampling with other methods for a Gumbel model. This study revealed that slice sampling algorithm offers more accurate and closer estimates with less RMSE than other methods . Finally we successfully employed this procedure to estimate the parameters of Malaysia extreme gold price from 2000 to 2011.

Reagent Precoated Targets for Rapid In-Tissue Derivatization of the Anti-Tuberculosis Drug Isoniazid Followed by MALDI Imaging Mass Spectrometry

NASA Astrophysics Data System (ADS)

Manier, M. Lisa; Reyzer, Michelle L.; Goh, Anne; Dartois, Veronique; Via, Laura E.; Barry, Clifton E.; Caprioli, Richard M.

2011-08-01

Isoniazid (INH) is an important component of front-line anti-tuberculosis therapy with good serum pharmacokinetics but unknown ability to penetrate tuberculous lesions. However, endogenous background interferences hinder our ability to directly analyze INH in tissues. Chemical derivatization has been successfully used to measure isoniazid directly from tissue samples using matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). MALDI targets were pretreated with trans-cinnamaldehyde (CA) prior to mounting tissue slices. Isoniazid present in the tissues was efficiently derivatized and the INH-CA product measured by MS/MS. Precoating of MALDI targets allows the tissues to be directly thaw-mounted and derivatized, thus simplifying the preparation. A time-course series of tissues from tuberculosis infected/INH dosed animals were assayed and the MALDI MS/MS response correlates well with the amount of INH determined to be in the tissues by high-performance liquid chromatography (HPLC)-MS/MS.

Magnetohydrodynamics of unsteady viscous fluid on boundary layer past a sliced sphere

NASA Astrophysics Data System (ADS)

Nursalim, Rahmat; Widodo, Basuki; Imron, Chairul

2017-10-01

Magnetohydrodynamics (MHD) is important study in engineering and industrial fields. By study on MHD, we can reach the fluid flow characteristics that can be used to minimize its negative effect to an object. In decades, MHD has been widely studied in various geometry forms and fluid types. The sliced sphere is a geometry form that has not been investigated. In this paper we study magnetohydrodynamics of unsteady viscous fluid on boundary layer past a sliced sphere. Assumed that the fluid is incompressible, there is no magnetic field, there is no electrical voltage, the sliced sphere is fix and there is no barrier around the object. In this paper we focus on velocity profile at stagnation point (x = 0°). Mathematical model is governed by continuity and momentum equation. It is converted to non-dimensional, stream function, and similarity equation. Solution of the mathematical model is obtained by using Keller-Box numerical method. By giving various of slicing angle and various of magnetic parameter we get the simulation results. The simulation results show that increasing the slicing angle causes the velocity profile be steeper. Also, increasing the value of magnetic parameter causes the velocity profile be steeper. On the large slicing angle there is no significant effect of magnetic parameter to velocity profile, and on the high the value of magnetic parameter there is no significant effect of slicing angle to velocity profile.

Accumulation of inositol polyphosphate isomers in agonist-stimulated cerebral-cortex slices. Comparison with metabolic profiles in cell-free preparations.

PubMed Central

Batty, I H; Letcher, A J; Nahorski, S R

1989-01-01

1. Basal and carbachol-stimulated accumulations of isomeric [3H]inositol mono-, bis-, tris- and tetrakis-phosphates were examined in rat cerebral-cortex slices labelled with myo-[2-3H]inositol. 2. In control samples the major [3H]inositol phosphates detected were co-eluted on h.p.l.c. with Ins(1)P, Ins(4)P (inositol 1- and 4-monophosphate respectively), Ins(1,4)P2 (inositol 1,4-bisphosphate), Ins(1,4,5)P3 (inositol 1,4,5-tris-phosphate) and Ins(1,3,4,5)P4 (inositol 1,3,4,5-tetrakisphosphate). 3. After stimulation to steady state with carbachol, accumulation of each of these products was markedly increased. 4. Agonist stimulation, however, also evoked much more dramatic increased accumulations of a second [3H]inositol trisphosphate, which was co-eluted on h.p.l.c. with authentic Ins(1,3,4)P3 (inositol 1,3,4-trisphosphate) and of three further [3H]inositol bisphosphates ([3H]InsP2(s]. 5. Examination of the latter by chemical degradation by periodate oxidation and/or h.p.l.c. allowed identification of these as [3H]Ins(1,3)P2, [3H]Ins(3,4)P2 and [3H]Ins(4,5)P2 (inositol 1,3-, 3,4- and 4,5-bisphosphates respectively), which respectively accounted for about 22%, 8% and 3% of total [3H]InsP2 in extracts from stimulated tissue slices. 6. By using a h.p.l.c. method which clearly resolves Ins(1,3,4,5)P4 and Ins(1,3,4,6)P4 (inositol 1,3,4,6-tetrakisphosphate), only the former isomer could be detected in extracts from either control or stimulated tissue slices. Similarly, [3H]inositol pentakis- and hexakis-phosphates were not detectable either in the presence or absence of carbachol under the radiolabelling conditions described. 7. The catabolism of [3H]Ins(1,4,5)P3 and [3H]Ins(1,3,4)P3 by cell-free preparations from cerebral cortex was also studied. 8. In the presence of Mg2+, [3H]Ins(1,4,5)P3 was specifically dephosphorylated via [3H]Ins(1,4)P2 and [3H]Ins(4)P to free [3H]inositol, whereas [3H]Ins(1,3,4)P3 was degraded via [3H]Ins(3,4)P2 and, to a lesser extent, via [3H]Ins(1,3)P2 to D- and/or L-[3H]Ins(1)P and [3H]inositol. 9. In the presence of EDTA, hydrolysis of [3H]Ins(1,4,5)P3 was greater than or equal to 95% inhibited, whereas [3H]Ins(1,3,4)P3 was still degraded, but yielded only a single [3H]InsP2 identified as [3H]Ins(1,3)P2. 10. The significance of these observations with cell-free preparations is discussed in relation to the proportions of the separate isomeric [3H]inositol phosphates measured in stimulated tissue slices. PMID:2930510

Can multi-slice or navigator-gated R2* MRI replace single-slice breath-hold acquisition for hepatic iron quantification?

PubMed

Loeffler, Ralf B; McCarville, M Beth; Wagstaff, Anne W; Smeltzer, Matthew P; Krafft, Axel J; Song, Ruitian; Hankins, Jane S; Hillenbrand, Claudia M

2017-01-01

Liver R2* values calculated from multi-gradient echo (mGRE) magnetic resonance images (MRI) are strongly correlated with hepatic iron concentration (HIC) as shown in several independently derived biopsy calibration studies. These calibrations were established for axial single-slice breath-hold imaging at the location of the portal vein. Scanning in multi-slice mode makes the exam more efficient, since whole-liver coverage can be achieved with two breath-holds and the optimal slice can be selected afterward. Navigator echoes remove the need for breath-holds and allow use in sedated patients. To evaluate if the existing biopsy calibrations can be applied to multi-slice and navigator-controlled mGRE imaging in children with hepatic iron overload, by testing if there is a bias-free correlation between single-slice R2* and multi-slice or multi-slice navigator controlled R2*. This study included MRI data from 71 patients with transfusional iron overload, who received an MRI exam to estimate HIC using gradient echo sequences. Patient scans contained 2 or 3 of the following imaging methods used for analysis: single-slice images (n = 71), multi-slice images (n = 69) and navigator-controlled images (n = 17). Small and large blood corrected region of interests were selected on axial images of the liver to obtain R2* values for all data sets. Bland-Altman and linear regression analysis were used to compare R2* values from single-slice images to those of multi-slice images and navigator-controlled images. Bland-Altman analysis showed that all imaging method comparisons were strongly associated with each other and had high correlation coefficients (0.98 ≤ r ≤ 1.00) with P-values ≤0.0001. Linear regression yielded slopes that were close to 1. We found that navigator-gated or breath-held multi-slice R2* MRI for HIC determination measures R2* values comparable to the biopsy-validated single-slice, single breath-hold scan. We conclude that these three R2* methods can be interchangeably used in existing R2*-HIC calibrations.

Quantitative Volumetric K-Means Cluster Segmentation of Fibroglandular Tissue and Skin in Breast MRI.

PubMed

Niukkanen, Anton; Arponen, Otso; Nykänen, Aki; Masarwah, Amro; Sutela, Anna; Liimatainen, Timo; Vanninen, Ritva; Sudah, Mazen

2017-10-18

Mammographic breast density (MBD) is the most commonly used method to assess the volume of fibroglandular tissue (FGT). However, MRI could provide a clinically feasible and more accurate alternative. There were three aims in this study: (1) to evaluate a clinically feasible method to quantify FGT with MRI, (2) to assess the inter-rater agreement of MRI-based volumetric measurements and (3) to compare them to measurements acquired using digital mammography and 3D tomosynthesis. This retrospective study examined 72 women (mean age 52.4 ± 12.3 years) with 105 disease-free breasts undergoing diagnostic 3.0-T breast MRI and either digital mammography or tomosynthesis. Two observers analyzed MRI images for breast and FGT volumes and FGT-% from T1-weighted images (0.7-, 2.0-, and 4.0-mm-thick slices) using K-means clustering, data from histogram, and active contour algorithms. Reference values were obtained with Quantra software. Inter-rater agreement for MRI measurements made with 2-mm-thick slices was excellent: for FGT-%, r = 0.994 (95% CI 0.990-0.997); for breast volume, r = 0.985 (95% CI 0.934-0.994); and for FGT volume, r = 0.979 (95% CI 0.958-0.989). MRI-based FGT-% correlated strongly with MBD in mammography (r = 0.819-0.904, P < 0.001) and moderately to high with MBD in tomosynthesis (r = 0.630-0.738, P < 0.001). K-means clustering-based assessments of the proportion of the fibroglandular tissue in the breast at MRI are highly reproducible. In the future, quantitative assessment of FGT-% to complement visual estimation of FGT should be performed on a more regular basis as it provides a component which can be incorporated into the individual's breast cancer risk stratification.

The influence of brain iron and myelin on magnetic susceptibility and effective transverse relaxation - A biochemical and histological validation study.

PubMed

Hametner, Simon; Endmayr, Verena; Deistung, Andreas; Palmrich, Pilar; Prihoda, Max; Haimburger, Evelin; Menard, Christian; Feng, Xiang; Haider, Thomas; Leisser, Marianne; Köck, Ulrike; Kaider, Alexandra; Höftberger, Romana; Robinson, Simon; Reichenbach, Jürgen R; Lassmann, Hans; Traxler, Hannes; Trattnig, Siegfried; Grabner, Günther

2018-06-15

Quantitative susceptibility mapping (QSM) and effective transverse relaxation rate (R2*) mapping are both highly sensitive to variations in brain iron content. Clinical Magnetic Resonance Imaging (MRI) studies report changes of susceptibilities and relaxation rates in various neurological diseases which are often equated with changes in regional brain iron content. However, these mentioned metrics lack specificity for iron, since they are also influenced by the presence of myelin. In this study, we assessed the extent to which QSM and R2* reflect iron concentration as well as histological iron and myelin intensities. Six unfixed human post-mortem brains were imaged in situ with a 7 T MRI scanner. After formalin fixation, the brains were sliced axially and punched. 671 tissue punches were subjected to ferrozine iron quantification. Subsequently, brain slices were embedded in paraffin, and histological double-hemispheric axial brain slices were stained for Luxol fast blue (myelin) and diaminobenzidine (DAB)-enhanced Turnbull blue (iron). 3331 regions of interest (ROIs) were drawn on the histological stainings to assess myelin and iron intensities, which were compared with MRI data in corresponding ROIs. QSM more closely reflected quantitative ferrozine iron values (r = 0.755 vs. 0.738), whereas R2* correlated better with iron staining intensities (r = 0.619 vs. 0.445). Myelin intensities correlated negatively with QSM (r = -0.352), indicating a diamagnetic effect of myelin on susceptibility. Myelin intensities were higher in the thalamus than in the basal ganglia. A significant relationship was nonetheless observed between quantitative iron values and QSM, confirming the applicability of the latter in this brain region for iron quantification. Copyright © 2018. Published by Elsevier Inc.

Vital-dye-enhanced multimodal imaging of neoplastic progression in a mouse model of oral carcinogenesis

NASA Astrophysics Data System (ADS)

Hellebust, Anne; Rosbach, Kelsey; Wu, Jessica Keren; Nguyen, Jennifer; Gillenwater, Ann; Vigneswaran, Nadarajah; Richards-Kortum, Rebecca

2013-12-01

In this longitudinal study, a mouse model of 4-nitroquinoline 1-oxide chemically induced tongue carcinogenesis was used to assess the ability of optical imaging with exogenous and endogenous contrast to detect neoplastic lesions in a heterogeneous mucosal surface. Widefield autofluorescence and fluorescence images of intact 2-NBDG-stained and proflavine-stained tissues were acquired at multiple time points in the carcinogenesis process. Confocal fluorescence images of transverse fresh tissue slices from the same specimens were acquired to investigate how changes in tissue microarchitecture affect widefield fluorescence images of intact tissue. Widefield images were analyzed to develop and evaluate an algorithm to delineate areas of dysplasia and cancer. A classification algorithm for the presence of neoplasia based on the mean fluorescence intensity of 2-NBDG staining and the standard deviation of the fluorescence intensity of proflavine staining was found to separate moderate dysplasia, severe dysplasia, and cancer from non-neoplastic regions of interest with 91% sensitivity and specificity. Results suggest this combination of noninvasive optical imaging modalities can be used in vivo to discriminate non-neoplastic from neoplastic tissue in this model with the potential to translate this technology to the clinic.

Whole abdominal wall segmentation using augmented active shape models (AASM) with multi-atlas label fusion and level set

NASA Astrophysics Data System (ADS)

Xu, Zhoubing; Baucom, Rebeccah B.; Abramson, Richard G.; Poulose, Benjamin K.; Landman, Bennett A.

2016-03-01

The abdominal wall is an important structure differentiating subcutaneous and visceral compartments and intimately involved with maintaining abdominal structure. Segmentation of the whole abdominal wall on routinely acquired computed tomography (CT) scans remains challenging due to variations and complexities of the wall and surrounding tissues. In this study, we propose a slice-wise augmented active shape model (AASM) approach to robustly segment both the outer and inner surfaces of the abdominal wall. Multi-atlas label fusion (MALF) and level set (LS) techniques are integrated into the traditional ASM framework. The AASM approach globally optimizes the landmark updates in the presence of complicated underlying local anatomical contexts. The proposed approach was validated on 184 axial slices of 20 CT scans. The Hausdorff distance against the manual segmentation was significantly reduced using proposed approach compared to that using ASM, MALF, and LS individually. Our segmentation of the whole abdominal wall enables the subcutaneous and visceral fat measurement, with high correlation to the measurement derived from manual segmentation. This study presents the first generic algorithm that combines ASM, MALF, and LS, and demonstrates practical application for automatically capturing visceral and subcutaneous fat volumes.

MIAQuant, a novel system for automatic segmentation, measurement, and localization comparison of different biomarkers from serialized histological slices.

PubMed

Casiraghi, Elena; Cossa, Mara; Huber, Veronica; Rivoltini, Licia; Tozzi, Matteo; Villa, Antonello; Vergani, Barbara

2017-11-02

In the clinical practice, automatic image analysis methods quickly quantizing histological results by objective and replicable methods are getting more and more necessary and widespread. Despite several commercial software products are available for this task, they are very little flexible, and provided as black boxes without modifiable source code. To overcome the aforementioned problems, we employed the commonly used MATLAB platform to develop an automatic method, MIAQuant, for the analysis of histochemical and immunohistochemical images, stained with various methods and acquired by different tools. It automatically extracts and quantifies markers characterized by various colors and shapes; furthermore, it aligns contiguous tissue slices stained by different markers and overlaps them with differing colors for visual comparison of their localization. Application of MIAQuant for clinical research fields, such as oncology and cardiovascular disease studies, has proven its efficacy, robustness and flexibility with respect to various problems; we highlight that, the flexibility of MIAQuant makes it an important tool to be exploited for basic researches where needs are constantly changing. MIAQuant software and its user manual are freely available for clinical studies, pathological research, and diagnosis.

The Impact of a 940 nm Diode Laser with Radial Firing Tip and Bare End Fiber Tip on Enterococcus faecalis in the Root Canal Wall Dentin of Bovine Teeth: An In Vitro Study.

PubMed

Schulte-Lünzum, Ruth; Gutknecht, Norbert; Conrads, Georg; Franzen, Rene

2017-07-01

This in vitro study aimed to compare the bactericidal effect of two different laser delivery systems, a radial firing tip (RFT) and bare end fiber tip (BFT) used with the 940 nm diode laser on Enterococcus faecalis inoculated onto bovine radicular dentin. A total of 100 bovine dentin slices with a defined thickness of 500 and 1000 μm were prepared. They were assigned into four test groups together with untreated samples served as control for each slice thickness. The slices were inoculated on one side with 1 μL E. faecalis suspension and laser irradiation was performed indirectly on the opposite side with the 940 nm diode laser delivered with a 200 μm RFT and a BFT at 1 and 1.5 W in continuous wave mode for 8 sec per cycle and repeated four times. After irradiation, the remaining bacteria were detached and the produced suspension was diluted and plated onto blood agar plates with 5% sheep blood and incubated overnight at 37°C in a CO 2 -rich atmosphere. The colony-forming units of E. faecalis were counted and the bacterial reduction was analyzed. The diode laser equipped with RFT fiber design further reduced the number of vital E. faecalis cells significantly compared with BFT design, regardless of the used power and dentin thickness (p < 0.0001). The highest average value of 4 log kills was observed in 500 μm slice thickness irradiated with RFT at 1.5 W. Temperature measurements on the external root surface at 1 mm from the apex did not elicit a harmful temperature elevation in both power settings and fiber designs. Within the studied parameters, 940 nm diode laser in conjugation with RFT showed a satisfactory bactericidal effect without any thermal side effect to the tooth-supporting tissues.

Protective effects of some creatine derivatives in brain tissue anoxia.

PubMed

Perasso, Luisa; Lunardi, Gian Luigi; Risso, Federica; Pohvozcheva, Anna V; Leko, Maria V; Gandolfo, Carlo; Florio, Tullio; Cupello, Aroldo; Burov, Sergey V; Balestrino, Maurizio

2008-05-01

Some derivatives more lipophylic than creatine, thus theoretically being capable to better cross the blood-brain barrier, were studied for their protective effect in mouse hippocampal slices. We found that N-amidino-piperidine is harmful to brain tissue, and that phosphocreatine is ineffective. Creatine, creatine-Mg-complex (acetate) and phosphocreatine-Mg-complex (acetate) increased the latency to population spike disappearance during anoxia. Creatine and creatine-Mg-complex (acetate) also increased the latency of anoxic depolarization, while the delay induced by phosphocreatine-Mg-complex (acetate) was of borderline significance (P = 0.056). Phosphocreatine-Mg-complex (acetate) significantly reduced neuronal hyperexcitability during anoxia, an effect that no other compound (including creatine itself) showed. For all parameters except reduced hyperexcitability the effects statistically correlated with tissue levels of creatine or phosphocreatine. Summing up, exogenous phosphocreatine and N-amidino piperidine are not useful for brain protection, while chelates of both creatine and phosphocreatine do replicate some of the known protective effects of creatine. In addition, phosphocreatine-Mg-complex (acetate) also reduced neuronal hyperexcitability during anoxia.

Use of light absorbers to alter optical interrogation with epi-illumination and transillumination in three-dimensional cardiac models

NASA Astrophysics Data System (ADS)

Ramshesh, Venkat K.; Knisley, Stephen B.

2006-03-01

Cardiac optical mapping currently provides 2-D maps of transmembrane voltage-sensitive fluorescence localized near the tissue surface. Methods for interrogation at different depths are required for studies of arrhythmias and the effects of defibrillation shocks in 3-D cardiac tissue. We model the effects of coloading with a dye that absorbs excitation or fluorescence light on the radius and depth of the interrogated region with specific illumination and collection techniques. Results indicate radii and depths of interrogation are larger for transillumination versus epi-illumination, an effect that is more pronounced for broad-field excitation versus laser scanner. Coloading with a fluorescence absorber lessens interrogated depth for epi-illumination and increases it for transillumination, which is confirmed with measurements using transillumination of heart tissue slices. Coloading with an absorber of excitation light consistently decreases the interrogated depths. Transillumination and coloading also decrease the intensities of collected fluorescence. Thus, localization can be modified with wavelength-specific absorbers at the expense of a reduction in fluorescence intensity.

Inter-study reproducibility of cardiovascular magnetic resonance tagging

PubMed Central

2013-01-01

Background The aim of this study is to determine the test-retest reliability of the measurement of regional myocardial function by cardiovascular magnetic resonance (CMR) tagging using spatial modulation of magnetization. Methods Twenty-five participants underwent CMR tagging twice over 12 ± 7 days. To assess the role of slice orientation on strain measurement, two healthy volunteers had a first exam, followed by image acquisition repeated with slices rotated ±15 degrees out of true short axis, followed by a second exam in the true short axis plane. To assess the role of slice location, two healthy volunteers had whole heart tagging. The harmonic phase (HARP) method was used to analyze the tagged images. Peak midwall circumferential strain (Ecc), radial strain (Err), Lambda 1, Lambda 2, and Angle α were determined in basal, mid and apical slices. LV torsion, systolic and early diastolic circumferential strain and torsion rates were also determined. Results LV Ecc and torsion had excellent intra-, interobserver, and inter-study intra-class correlation coefficients (ICC range, 0.7 to 0.9). Err, Lambda 1, Lambda 2 and angle had excellent intra- and interobserver ICC than inter-study ICC. Angle had least inter-study reproducibility. Torsion rates had superior intra-, interobserver, and inter-study reproducibility to strain rates. The measurements of LV Ecc were comparable in all three slices with different short axis orientations (standard deviation of mean Ecc was 0.09, 0.18 and 0.16 at basal, mid and apical slices, respectively). The mean difference in LV Ecc between slices was more pronounced in most of the basal slices compared to the rest of the heart. Conclusions Intraobserver and interobserver reproducibility of all strain and torsion parameters was excellent. Inter-study reproducibility of CMR tagging by SPAMM varied between different parameters as described in the results above and was superior for Ecc and LV torsion. The variation in LV Ecc measurement due to altered slice orientation is negligible compared to the variation due to slice location. Trial registration This trial is registered as NCT00005487 at National Heart, Lung and Blood institute. PMID:23663535

Clinical evaluation of MR temperature monitoring of laser-induced thermotherapy in human liver using the proton-resonance-frequency method and predictive models of cell death.

PubMed

Kickhefel, Antje; Rosenberg, Christian; Weiss, Clifford R; Rempp, Hansjörg; Roland, Joerg; Schick, Fritz; Hosten, Norbert

2011-03-01

To assess the feasibility, precision, and accuracy of real-time temperature mapping (TMap) during laser-induced thermotherapy (LITT) for clinical practice in patients liver with a gradient echo (GRE) sequence using the proton resonance frequency (PRF) method. LITT was performed on 34 lesions in 18 patients with simultaneous real-time visualization of relative temperature changes. Correlative contrast-enhanced T1-weighted magnetic resonance (MR) images of the liver were acquired after treatment using the same slice positions and angulations as TMap images acquired during LITT. For each slice, TMap and follow-up images were registered for comparison. Afterwards, segmentation based on temperature (T) >52°C on TMap and based on necrosis seen on follow-up images was performed. These segmented structures were overlaid and divided into zones where the TMap was found to either over- or underestimate necrosis on the postcontrast images. Regions with T>52°C after 20 minutes were defined as necrotic tissue based on data received from two different thermal dose models. The average intersecting region of TMap and necrotic zone was 87% ± 5%, the overestimated 13% ± 4%, and the underestimated 13% ± 5%. This study demonstrates that MR temperature mapping appears reasonably capable of predicting tissue necrosis on the basis of indicating regions having greater temperatures than 52°C and could be used to monitor and adjust the thermal therapy appropriately during treatment. Copyright © 2011 Wiley-Liss, Inc.

Enhanced taurine release in cell-damaging conditions in the developing and ageing mouse hippocampus.

PubMed

Saransaari, P; Oja, S S

1997-08-01

Taurine has been shown to be essential for neuronal development and survival in the central nervous system. The release of preloaded [3H]taurine was studied in hippocampal slices from seven-day-, three-month- and 18-22-month-old mice in cell-damaging conditions. The slices were superfused in hypoxic, hypoglycemic and ischemic conditions and exposed to free radicals and oxidative stress. The release of taurine was greatly enhanced in the above conditions in all age groups, except in oxidative stress. The release was large in ischemia, particularly in the hippocampus of aged mice. Potassium stimulation was still able to release taurine in cell-damaging conditions in immature mice, whereas in adult and aged animals the release was so substantial that this additional stimulus failed to work. Taurine release was partially Ca2+-dependent in all cases. The massive release of the inhibitory amino acid taurine in ischemic conditions could act neuroprotectively, counteracting in several ways the effects of simultaneous release of excitatory amino acids. This protection could be of great importance in developing brain tissue, while also having an effect in aged brains.

A fast stimulability screening protocol for neuronal cultures on microelectrode arrays.

PubMed

Kapucu, Fikret E; Tanskanen, Jarno M A; Yuan, Yuting; Hyttinen, Jari A K

2015-01-01

Microelectrode arrays (MEAs) are used to study the electrical activity in brain slices and neuronal cultures. MEA experiments for the analysis of electrical stimulation responses require the tissue or culture to be prone to stimulation. For brain slices, potential stimulation sites may be directly visible in microscope, in which case the determination of stimulability at those locations is sufficient. In unstructured neuronal cultures, potential stimulation sites may not be known a priori, and spatial stimulability screening should be performed. Considering, e.g., 59 microelectrode sites, each to be stimulated several times, may result in long screening times, unacceptable with a MEA system without an integrated CO2 incubator, or in high stimulation effects on the networks. Here, we describe an implementation of a fast stimulation protocol employing pseudorandom stimulation site switching aiming at alleviating the network effects of the stimulability screening. In this paper, we show the usability of the proposed protocol by first detecting stimulable locations and subsequently apply repeated stimulation on the identified potentially stimulable locations to observe an exemplary neuronal pathway.

Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators

PubMed Central

Chamberland, Simon; Yang, Helen H; Pan, Michael M; Evans, Stephen W; Guan, Sihui; Chavarha, Mariya; Yang, Ying; Salesse, Charleen; Wu, Haodi; Wu, Joseph C; Clandinin, Thomas R; Toth, Katalin; Lin, Michael Z; St-Pierre, François

2017-01-01

Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila. These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision. DOI: http://dx.doi.org/10.7554/eLife.25690.001 PMID:28749338

A microelectrode array electrodeposited with reduced graphene oxide and Pt nanoparticles for norepinephrine and electrophysiological recordings

NASA Astrophysics Data System (ADS)

Wang, Li; Song, Yilin; Zhang, Yu; Xu, Shengwei; Xu, Huiren; Wang, Mixia; Wang, Yang; Cai, Xinxia

2017-11-01

Norepinephrine (NE), a common neurotransmitter released by locus coeruleus neurons, plays an essential role in the communication mechanism of the mammalian nervous system. In this work, a microelectrode array (MEA) was fabricated by micro-electromechanical system (MEMS) technology to provide a rapid, sensitive and reliable method for the direct determination in NE dynamic secretion. To improve the electrical performance, the MEA was electrodeposited with the reduced graphene oxide and Pt nanoparticles (rGOPNps). rGOPNps-MEA was investigated using scanning electron microscopy, atomic force microscopy and electrochemical impedance spectroscopy, differential pulse voltammetry exhibited remarkably electrocatalytic properties towards NE. Calibration results showed a sensitivity of 1.03 nA µM-1 to NE with a detection limit of 0.08 µM. In Particular, the MEA was successfully used for measuring dynamic extracellular NE secretion from the locus coeruleus brain slice, as well as monitoring spike firing from the hippocampal brain slice. This fabricated device has potential in studies of spatially resolved delivery of trace neurochemicals and electrophysiological activities of a variety of biological tissues in vitro.

Evaluation of radiation dose of triple rule-out coronary angiography protocols with different scan length using 256-slice CT

NASA Astrophysics Data System (ADS)

Tsai, Chia-Jung; Lee, Jason J. S.; Chen, Liang-Kuang; Mok, Greta S. P.; Hsu, Shih-Ming; Wu, Tung-Hsin

2011-10-01

Triple rule-out coronary CT angiography (TRO-CTA) is a new approach for providing noninvasive visualization of coronary arteries with simultaneous evaluation of pulmonary arteries, thoracic aorta and other intrathoracic structures. The increasing use of TRO-CTA examination with longer scan length is associated with the concerns about radiation dose and their corresponding cancer risk. The purpose of this study is to evaluate organ dose and effective dose for the TRO-CTA examination with 2 scan lengths: TRO std and TRO ext, using 256-slice CT. TRO-CTA examinations were performed on a 256-slice CT scanner without ECG-based tube current modulation. Absorbed organ doses were measured using an anthropomorphic phantom and thermal-luminance dosimeters (TLDs). Effective dose was determined by taking a sum of the measured absorbed organ doses multiplied with the tissue weighting factor based on ICRP-103, and compared to that calculated using the dose-length product (DLP) method. We obtained high organ doses in the thyroid, esophagus, breast, heart and lung in both TRO-CTA protocols. Effective doses of the TRO std and TRO ext protocols with the phantom method were 26.37 and 42.49 mSv, while those with the DLP method were 19.68 and 38.96 mSv, respectively. Our quantitative dose information establishes a relationship between radiation dose and scanning length, and can provide a practical guidance to best clinical practice.

Higher transport and metabolism of glucose in astrocytes compared with neurons: a multiphoton study of hippocampal and cerebellar tissue slices.

PubMed

Jakoby, Patrick; Schmidt, Elke; Ruminot, Iván; Gutiérrez, Robin; Barros, L Felipe; Deitmer, Joachim W

2014-01-01

Glucose is the most important energy substrate for the brain, and its cellular distribution is a subject of great current interest. We have employed fluorescent glucose probes, the 2-deoxy-D-glucose derivates 6- and 2-([N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose) (2-NBDG), to measure transport and metabolism of glucose in acute slices of mouse hippocampus and cerebellum. In the hippocampus, 6-NBDG, which is not metabolized and hence indicates glucose transport, was taken up faster in astrocyte-rich layers (Stratum radiatum [S.r.], Stratum oriens [S.o.]) than in pyramidal cells. Metabolizable 2-NBDG showed larger signals in S.r. and S.o. than in Stratum pyramidale, suggesting faster glucose utilization rate in the astrocyte versus the neuronal compartment. Similarly, we found higher uptake and temperature-sensitive metabolism of 2-NBDG in Bergmann glia when compared with adjacent Purkinje neurons of cerebellar slices. A comparison between 6-NBDG transport and glucose transport in cultured cells using a fluorescence resonance energy transfer nanosensor showed that relative to glucose, 6-NBDG is transported better by neurons than by astrocytes. These results indicate that the preferential transport and metabolism of glucose by glial cells versus neurons proposed for the hippocampus and cerebellum by ourselves (in vitro) and for the barrel cortex by Chuquet et al. (in vivo) is more pronounced than anticipated.

Orthodontic decompensation in skeletal Class III malocclusion: redefining the amount of movement assessed by Cone-Beam Computed Tomography

PubMed Central

Cappellozza, José Antonio Zuega; Guedes, Fabio Pinto; Nary, Hugo; Capelozza, Leopoldino; Cardoso, Mauricio de Almeida

2015-01-01

Introduction: Cone-Beam Computed Tomography (CBCT) is essential for tridimensional planning of orthognathic surgery, as it allows visualization and evaluation of bone structures and mineralized tissues. Tomographic slices allow evaluation of tooth inclination and individualization of movement performed during preoperative decompensation. The aim of this paper was to assess maxillary and mandibular incisors inclination pre and post orthodontic decompensation in skeletal Class III malocclusion. Methods: The study was conducted on six individuals with skeletal Class III malocclusion, surgically treated, who had Cone-Beam Computed Tomographic scans obtained before and after orthodontic decompensation. On multiplanar reconstruction view, tomographic slices (axial, coronal and sagittal) were obtained on the long axis of each incisor. The sagittal slice was used for measurement taking, whereas the references used to assess tooth inclination were the long axis of maxillary teeth in relation to the palatal plane and the long axis of mandibular teeth in relation to the mandibular plane. Results: There was significant variation in the inclination of incisors before and after orthodontic decompensation. This change was of greater magnitude in the mandibular arch, evidencing that natural compensation is more effective in this arch, thereby requiring more intensive decompensation. Conclusion: When routinely performed, the protocols of decompensation treatment in surgical individuals often result in intensive movements, which should be reevaluated, since the extent of movement predisposes to reduction in bone attachment levels and root length. PMID:26560818

Quality of tomato slices disinfected with ozonated water.

PubMed

Aguayo, Encarna; Escalona, Víctor; Silveira, Ana Cecilia; Artés, Francisco

2014-04-01

Fresh-cut industry needs novel disinfectant to replace the use of chlorine. Ozone is one of the most powerful oxidizing agents and is applied in gaseous or aqueous form for sanitation purposes. However, the strong oxidative effect could affect the nutritional and sensorial quality, in particular, when time of washing is extended. For that reason, the overall impact of ozonated water (0.4 mg/L) dipping applied during 1, 3 and 5 min compared to control washed in water during 5 min was studied in tomato slices stored during 14 days at 5 . According to the results, ozonated water treatment of 3 min achieved the best firmness retention, microbial quality (mesophilic, psychrotrophic and yeas load) and reduced the consumption of fructose and glucose. The use of ozonated water did not affect the total acidity, pH, total solid soluble, organic acid as ascorbic, fumaric or succinic acid and the sensorial parameters, which were only affected by storage time. However, the poor appearance, aroma and overall quality obtained in all treatments prevented shelf life of 14 days and the quality at acceptable levels was established in 10 days at 5 . It is recommended to wash tomato slices with 0.4 mg/L ozonated water for 3 min only. Extending treatment duration did not improve the microbiological quality, possibly due to the extra time permitting the ozone to react with other components of the fruit tissue, undermining the antimicrobial benefits.

Responses to Gamma-Aminobutyric Acid of Rat Visual Cortical Neurons in Tissue Slices

DTIC Science & Technology

1986-04-01

depolarizing afterpotentials ( DAPs ; Figure 3). The afterhyperpolarization (AHP) was defined as the hyperpolarization that follow one or more orthodromic...action potentials or action potentials elicited during a depolarizing current pulse (Figure 3). DAPs and AHPs were measured from the RMP. The term...inhibitory postsynaptic potential, DAP = depolarizing afterpotential, AHP= afterhyperpolarization. Dashed lines indicate the RMP. Asterisks indicate

Interaction of a vasopressin antagonist with vasopressin receptors in the septum of the rat brain

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

Dorsa, D.M.; Brot, M.D.; Shewey, L.M.

1988-01-01

The ability of d(CH2)5-Tyr(Me)-arginine-8-vasopressin, an antagonist of peripheral pressoric (V1-type) vasopressin receptors, to label vasopressin binding sites in the septum of the rat brain was evaluated. Using crude membrane preparations from the septum, /sup 3/H-arginine-8-vasopressin (AVP) specifically labels a single class of binding sites with a Kd of 2.9 nM and maximum binding site concentration of 19.8 fmole/mg protein. /sup 3/H-Antag also labels a single class of membrane sites but with higher affinity (Kd = 0.47 nM) and lower capacity (10.1 fmole/mg protein) than /sup 3/H-AVP. The rank order of potency of various competitor peptides for /sup 3/H-AVP and /supmore » 3/H-Antag binding was similar. Oxytocin was 100-1,000 fold less potent than AVP in competing for binding with both ligands. /sup 3/H-AVP and /sup 3/H-Antag showed similar labeling patterns when incubated with septal tissue slices. Unlabeled Antag also effectively antagonized vasopressin-stimulated phosphatidylinositol hydrolysis in septal tissue slices.« less

The Effect of Temperature on Photoluminescence Enhancement of Quantum Dots in Brain Slices.

PubMed

Zhao, Fei; Kim, Jongsung

2017-04-01

In this paper, we investigated the effect of temperature on photoluminescence of quantum dots immobilized on the surface of an optical fiber in a rat brain slice. The optical fiber was silanized with 3-aminopropyl trimethoxysilane (APTMS), following which quantum dots with carboxyl functional group were immobilized on the optical fiber via amide bond formation. The effect of temperature on the fluorescence intensity of the quantum dots in rat brain slices was studied. This report shows that the fluorescence intensity of quantum dots increases with the increase of temperature of the brain slice. The fluorescence enhancement phenomenon appears to take place via electron transfer related to pH increase. With the gradual increase of temperature, the fluorescence intensity of quantum dots in solution decreased, while that in the brain slice increased. This enhanced thermal performance of QDs in brain slice makes suggestion for the study of QDs-based brain temperature sensors.

Thin slices of child personality: Perceptual, situational, and behavioral contributions.

PubMed

Tackett, Jennifer L; Herzhoff, Kathrin; Kushner, Shauna C; Rule, Nicholas

2016-01-01

The present study examined whether thin-slice ratings of child personality serve as a resource-efficient and theoretically valid measurement of child personality traits. We extended theoretical work on the observability, perceptual accuracy, and situational consistency of childhood personality traits by examining intersource and interjudge agreement, cross-situational consistency, and convergent, divergent, and predictive validity of thin-slice ratings. Forty-five unacquainted independent coders rated 326 children's (ages 8-12) personality in 1 of 15 thin-slice behavioral scenarios (i.e., 3 raters per slice, for over 14,000 independent thin-slice ratings). Mothers, fathers, and children rated children's personality, psychopathology, and competence. We found robust evidence for correlations between thin-slice and mother/father ratings of child personality, within- and across-task consistency of thin-slice ratings, and convergent and divergent validity with psychopathology and competence. Surprisingly, thin-slice ratings were more consistent across situations in this child sample than previously found for adults. Taken together, these results suggest that thin slices are a valid and reliable measure to assess child personality, offering a useful method of measurement beyond questionnaires, helping to address novel questions of personality perception and consistency in childhood. (c) 2016 APA, all rights reserved).

Immunocytochemical detection of astrocytes in brain slices in combination with Nissl staining.

PubMed

Korzhevskii, D E; Otellin, V A

2005-07-01

The present study was performed to develop a simple and reliable method for the combined staining of specimens to allow the advantages of immunocytochemical detection of astrocytes and assessment of the functional state of neurons by the Nissl method to be assessed simultaneously. The protocol suggested for processing paraffin sections allows preservation of tissue structure at high quality and allows the selective identification of astrocytes with counterstaining of neurons by the Nissl method. The protocol can be used without modification for processing brain specimens from humans and various mammals--except mice and rabbits.

Differentiation of tumor from viable myocardium using cardiac tagging with MR imaging.

PubMed

Bouton, S; Yang, A; McCrindle, B W; Kidd, L; McVeigh, E R; Zerhouni, E A

1991-01-01

We report the application of myocardial tagging by MR to define tissue planes and differentiate contractile from noncontractile tissue in a neonate with congenital cardiac rhabdomyoma. Using custom-written pulse programming software, six 2 mm thick radiofrequency (RF) slice-selective presaturation pulses (tags) were used to label the chest wall and myocardium in a star pattern in diastole, approximately 60 ms before the R-wave gating trigger. This method successfully delineated the myocardium from noncontractile tumor, providing information that influenced clinical management. This RF tagging technique allowed us to confirm the exact intramyocardial location of a congenital cardiac tumor.

Soft tissue rapid prototyping in neurosurgery.

PubMed

Vloeberghs, M; Hatfield, F; Daemi, F; Dickens, P

1998-01-01

As part of our research into the fluid hydrodynamics of the human ventricular system, a fused deposition model of the human ventricular system was made using magnetic resonance imaging (MRI) data. This article describes the manufacturing of a positive cast of the ventricles as a first step in the construction of a hollow model. After decryption of the original MRI file (ACR-Nema format), the MRI slices were reassembled semiautomatically and a rapid prototyping station produced a resin model. Because of its ease and speed, this method harbors great potential for teaching purposes, research, and preoperative planning in complex three-dimensional soft tissue targets.

Acute Hippocampal Slice Preparation and Hippocampal Slice Cultures

PubMed Central

Lein, Pamela J.; Barnhart, Christopher D.; Pessah, Isaac N.

2012-01-01

A major advantage of hippocampal slice preparations is that the cytoarchitecture and synaptic circuits of the hippocampus are largely retained. In neurotoxicology research, organotypic hippocampal slices have mostly been used as acute ex vivo preparations for investigating the effects of neurotoxic chemicals on synaptic function. More recently, hippocampal slice cultures, which can be maintained for several weeks to several months in vitro, have been employed to study how neurotoxic chemicals influence the structural and functional plasticity in hippocampal neurons. This chapter provides protocols for preparing hippocampal slices to be used acutely for electrophysiological measurements using glass microelectrodes or microelectrode arrays or to be cultured for morphometric assessments of individual neurons labeled using biolistics. PMID:21815062

Accuracy of limited four-slice CT-scan in diagnosis of chronic rhinosinusitis.

PubMed

Zojaji, R; Nekooei, S; Naghibi, S; Mazloum Farsi Baf, M; Jalilian, R; Masoomi, M

2015-12-01

Chronic rhinosinusitis (CRS) is a common chronic health condition worldwide. Standard CT-scan is the method of choice for diagnosis of CRS but its high price and considerable radiation exposure have limited its application. The main goal of this study was to evaluate the accuracy of limited four-slice coronal CT-scan in the diagnosis of CRS. This cross-sectional study was conducted on 46 patients with CRS, for one year, based on American Society of Head and Neck Surgery criteria. All patients received the preoperative standard and four-slice CT-scans, after which endoscopic sinus surgery was performed. Findings of four-slice CT-scans were compared with those of conventional CT-scan and the sensitivity and specificity of four-slice CT-scan and its agreement with conventional CT-scan was calculated. In this study, 46 patients including 32 males (69.6%) and 14 females (30.46%) with a mean age of 33 and standard deviation of 9 years, were evaluated. Sensitivity and specificity of four-slice CT-scan were 97.5% and 100%, respectively. Also, positive predictive value (PPV) and negative predictive value (NPV) of four-slice CT was 100% and 85.71%, respectively. There was a strong agreement between four-slice CT and conventional CT findings. Considering the high sensitivity and specificity of four-slice CT-scan and strong agreement with conventional CT-scan in the diagnosis of CRS and the lower radiation exposure and cost, application of this method is suggested for both diagnosis and treatment follow-up in CRS. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Correlation between model observers in uniform background and human observers in patient liver background for a low-contrast detection task in CT

NASA Astrophysics Data System (ADS)

Gong, Hao; Yu, Lifeng; Leng, Shuai; Dilger, Samantha; Zhou, Wei; Ren, Liqiang; McCollough, Cynthia H.

2018-03-01

Channelized Hotelling observer (CHO) has demonstrated strong correlation with human observer (HO) in both single-slice viewing mode and multi-slice viewing mode in low-contrast detection tasks with uniform background. However, it remains unknown if the simplest single-slice CHO in uniform background can be used to predict human observer performance in more realistic tasks that involve patient anatomical background and multi-slice viewing mode. In this study, we aim to investigate the correlation between CHO in a uniform water background and human observer performance at a multi-slice viewing mode on patient liver background for a low-contrast lesion detection task. The human observer study was performed on CT images from 7 abdominal CT exams. A noise insertion tool was employed to synthesize CT scans at two additional dose levels. A validated lesion insertion tool was used to numerically insert metastatic liver lesions of various sizes and contrasts into both phantom and patient images. We selected 12 conditions out of 72 possible experimental conditions to evaluate the correlation at various radiation doses, lesion sizes, lesion contrasts and reconstruction algorithms. CHO with both single and multi-slice viewing modes were strongly correlated with HO. The corresponding Pearson's correlation coefficient was 0.982 (with 95% confidence interval (CI) [0.936, 0.995]) and 0.989 (with 95% CI of [0.960, 0.997]) in multi-slice and single-slice viewing modes, respectively. Therefore, this study demonstrated the potential to use the simplest single-slice CHO to assess image quality for more realistic clinically relevant CT detection tasks.

A LED-based method for monitoring NAD(P)H and FAD fluorescence in cell cultures and brain slices.

PubMed

Rösner, Jörg; Liotta, Agustin; Schmitz, Dietmar; Heinemann, Uwe; Kovács, Richard

2013-01-30

Nicotinamide- and flavine-adenine-dinucleotides (NAD(P)H and FADH₂) are electron carriers involved in cellular energy metabolism and in a multitude of enzymatic processes. As reduced NAD(P)H and oxidised FAD molecules are fluorescent, changes in tissue auto-fluorescence provide valuable information on the cellular redox state and energy metabolism. Since fluorescence excitation, by mercury arc lamps (HBO) is inherently coupled to photo-bleaching and photo-toxicity, microfluorimetric monitoring of energy metabolism might benefit from the replacement of HBO lamps by light emitting diodes (LEDs). Here we describe a LED-based custom-built setup for monitoring NAD(P)H and FAD fluorescence at the level of single cells (HEK293) and of brain slices. We compared NAD(P)H bleaching characteristics with two light sources (HBO lamp and LED) as well as sensitivity and signal to noise ratio of three different detector types (multi-pixel photon counter (MPPC), photomultiplier tube (PMT) and photodiode). LED excitation resulted in reduced photo-bleaching at the same fluorescence output in comparison to excitation with the HBO lamp. Transiently increasing LED power resulted in reversible bleaching of NAD(P)H fluorescence. Recovery kinetics were dependent on metabolic substrates indicating coupling of NAD(P)H fluorescence to metabolism. Electrical stimulation of brain slices induced biphasic redox changes, as indicated by NAD(P)H/FAD fluorescence transients. Increasing the gain of PMT and decreasing the LED power resulted in similar sensitivity as obtained with the MPPC and the photodiode, without worsening the signal to noise ratio. In conclusion, replacement of HBO lamp with LED might improve conventional PMT based microfluorimetry of tissue auto-fluorescence. Copyright © 2012 Elsevier B.V. All rights reserved.

Sliced Costochondral Chip Grafts in Posttraumatic Enophthalmos Correction.

PubMed

Kim, Tae-Hoon; Park, Ie-Hyon; Hong, Sa-Hyeok; Eun, Seok-Chan

2017-03-01

Posttraumatic enophthalmos is a relatively common problem following orbitozygomatic fractures. However, inadequate long-term results are frequently observed due to the difficulty of performing intraoperative fine adjustments to soft-tissue volume and orbital size and gradual absorption of some grafted materials. Here, the authors describe an efficient method of enophthalmos correction using sliced costochondral bone and cartilage combination grafts. From 2005 to 2011, the authors corrected enophthalmos in 12 patients using sliced costochondral grafts. The mean follow-up period was 13 months. For costochondral graft harvest, an approximately 5-cm skin incision was made directly above the seventh costal cartilage, the perichondrium was peeled back, and a small piece of rib bone and costal cartilage was harvested from the anterior part of the seventh rib bone and cartilage and cut into 2-mm-thick slices. A subciliary and/or transcaruncular incision was made in the affected side eyelid to expose the operating field, subperiosteal dissection was performed in the orbit and orbital floor. The cartilage chips were gradually grafted onto the dissected areas from the posterior orbit. Aesthetically satisfactory results were obtained in all patients. No complications in the donor area were observed. Furthermore, no patients experienced a recurrence or deterioration of diplopia over the follow-up period. One patient experienced temporary high intraocular pressure, which spontaneously resolved with medication and eye drops. The costochondral graft is adequate for the reconstruction of the fracture, easy to obtain, easily adaptable to the orbital walls, and has minimal morbidity at the donor site.

Physiological temperature during brain slicing enhances the quality of acute slice preparations

PubMed Central

Huang, Shiwei; Uusisaari, Marylka Y.

2013-01-01

We demonstrate that brain dissection and slicing using solutions warmed to near-physiological temperature (~ +34°C), greatly enhance slice quality without affecting intrinsic electrophysiological properties of the neurons. Improved slice quality is seen not only when using young (<1 month), but also mature (>2.5 month) mice. This allows easy in vitro patch-clamp experimentation using adult deep cerebellar nuclear slices, which until now have been considered very difficult. As proof of the concept, we compare intrinsic properties of cerebellar nuclear neurons in juvenile (<1 month) and adult (up to 7 months) mice, and confirm that no significant developmental changes occur after the fourth postnatal week. The enhanced quality of brain slices from old animals facilitates experimentation on age-related disorders as well as optogenetic studies requiring long transfection periods. PMID:23630465

SU-E-T-481: Dosimetric Effects of Tissue Heterogeneity in Proton Therapy: Monte Carlo Simulation and Experimental Study Using Animal Tissue Phantoms.

PubMed

Liu, Y; Zheng, Y

2012-06-01

Accurate determination of proton dosimetric effect for tissue heterogeneity is critical in proton therapy. Proton beams have finite range and consequently tissue heterogeneity plays a more critical role in proton therapy. The purpose of this study is to investigate the tissue heterogeneity effect in proton dosimetry based on anatomical-based Monte Carlo simulation using animal tissues. Animal tissues including a pig head and beef bulk were used in this study. Both pig head and beef were scanned using a GE CT scanner with 1.25 mm slice thickness. A treatment plan was created, using the CMS XiO treatment planning system (TPS) with a single proton spread-out-Bragg-peak beam (SOBP). Radiochromic films were placed at the distal falloff region. Image guidance was used to align the phantom before proton beams were delivered according to the treatment plan. The same two CT sets were converted to Monte Carlo simulation model. The Monte Carlo simulated dose calculations with/without tissue omposition were compared to TPS calculations and measurements. Based on the preliminary comparison, at the center of SOBP plane, the Monte Carlo simulation dose without tissue composition agreed generally well with TPS calculation. In the distal falloff region, the dose difference was large, and about 2 mm isodose line shift was observed with the consideration of tissue composition. The detailed comparison of dose distributions between Monte Carlo simulation, TPS calculations and measurements is underway. Accurate proton dose calculations are challenging in proton treatment planning for heterogeneous tissues. Tissue heterogeneity and tissue composition may lead to isodose line shifts up to a few millimeters in the distal falloff region. By simulating detailed particle transport and energy deposition, Monte Carlo simulations provide a verification method in proton dose calculation where inhomogeneous tissues are present. © 2012 American Association of Physicists in Medicine.

Three-dimensional Model of Tissue and Heavy Ions Effects

NASA Technical Reports Server (NTRS)

Ponomarev, Artem L.; Sundaresan, Alamelu; Huff, Janice L.; Cucinotta, Francis A.

2007-01-01

A three-dimensional tissue model was incorporated into a new Monte Carlo algorithm that simulates passage of heavy ions in a tissue box . The tissue box was given as a realistic model of tissue based on confocal microscopy images. The action of heavy ions on the cellular matrix for 2- or 3-dimensional cases was simulated. Cells were modeled as a cell culture monolayer in one example, where the data were taken directly from microscopy (2-d cell matrix), and as a multi-layer obtained from confocal microscopy (3-d case). Image segmentation was used to identify cells with precise areas/volumes in an irradiated cell culture monolayer, and slices of tissue with many cell layers. The cells were then inserted into the model box of the simulated physical space pixel by pixel. In the case of modeled tissues (3-d), the tissue box had periodic boundary conditions imposed, which extrapolates the technique to macroscopic volumes of tissue. For the real tissue (3-d), specific spatial patterns for cell apoptosis and necrosis are expected. The cell patterns were modeled based on action cross sections for apoptosis and necrosis estimated from current experimental data. A spatial correlation function indicating a higher spatial concentration of damaged cells from heavy ions relative to the low-LET radiation cell damage pattern is presented. The spatial correlation effects among necrotic cells can help studying microlesions in organs, and probable effects of directionality of heavy ion radiation on epithelium and endothelium.

Examining the Complex Regulation and Drug-Induced Plasticity of Dopamine Release and Uptake Using Voltammetry in Brain Slices

PubMed Central

2013-01-01

Fast scan cyclic voltammetry in brain slices (slice voltammetry) has been used over the last several decades to increase substantially our understanding of the complex local regulation of dopamine release and uptake in the striatum. This technique is routinely used for the study of changes that occur in the dopamine system associated with various disease states and pharmacological treatments, and to study mechanisms of local circuitry regulation of dopamine terminal function. In the context of this Review, we compare the relative advantages of voltammetry using striatal slice preparations versus in vivo preparations, and highlight recent advances in our understanding of dopamine release and uptake in the striatum specifically from studies that use slice voltammetry in drug-naïve animals and animals with a history of psychostimulant self-administration. PMID:23581570

Computed Tomography of the Normal Bovine Tarsus.

PubMed

Hagag, U; Tawfiek, M; Brehm, W; Gerlach, K

2016-12-01

The objective of this study was to provide a detailed multiplanar computed tomographic (CT) anatomic reference for the bovine tarsus. The tarsal regions from twelve healthy adult cow cadavers were scanned in both soft and bone windows via a 16-slice multidetector CT scanner. Tarsi were frozen at -20 o C and sectioned to 10-mm-thick slices in transverse, dorsal and sagittal planes respecting the imaging protocol. The frozen sections were cleaned and then photographed. Anatomic structures were identified, labelled and compared with the corresponding CT images. The sagittal plane was indispensable for evaluation of bone contours, the dorsal plane was valuable in examination of the collateral ligaments, and both were beneficial for assessment of the tarsal joint articulations. CT images allowed excellent delineation between the cortex and medulla of bones, and the trabecular structure was clearly depicted. The tarsal soft tissues showed variable shades of grey, and the synovial fluid was the lowest attenuated structure. This study provided full assessment of the clinically relevant anatomic structures of the bovine tarsal joint. This technique may be of value when results from other diagnostic imaging techniques are indecisive. Images presented in this study should serve as a basic CT reference and assist in the interpretation of various bovine tarsal pathology. © 2016 Blackwell Verlag GmbH.

3D resolved mapping of optical aberrations in thick tissues

PubMed Central

Zeng, Jun; Mahou, Pierre; Schanne-Klein, Marie-Claire; Beaurepaire, Emmanuel; Débarre, Delphine

2012-01-01

We demonstrate a simple method for mapping optical aberrations with 3D resolution within thick samples. The method relies on the local measurement of the variation in image quality with externally applied aberrations. We discuss the accuracy of the method as a function of the signal strength and of the aberration amplitude and we derive the achievable resolution for the resulting measurements. We then report on measured 3D aberration maps in human skin biopsies and mouse brain slices. From these data, we analyse the consequences of tissue structure and refractive index distribution on aberrations and imaging depth in normal and cleared tissue samples. The aberration maps allow the estimation of the typical aplanetism region size over which aberrations can be uniformly corrected. This method and data pave the way towards efficient correction strategies for tissue imaging applications. PMID:22876353

Reactive oxygen species' role in endothelial dysfunction by electron paramagnetic resonance

NASA Astrophysics Data System (ADS)

Wassall, Cynthia D.

The endothelium is a single layer of cells lining the arteries and is involved in many physiological reactions which are responsible for vascular tone. Free radicals are important participants in these chemical reactions in the endothelium. Here we quantify free radicals, ex vivo, in biological tissue with continuous wave electron paramagnetic resonance (EPR). In all of the experiments in this thesis, we use a novel EPR spin trapping technique that has been developed for tissue segments. EPR spin trapping is often considered the 'gold standard' in reactive oxygen species (ROS) detection because of its sensitivity and non-invasive nature. In all experiments, tissue was placed in physiological saline solution with 190-mM PBN (N-tert -butyl-α-phenylnitrone), 10% by volume dimethyl-sulphoxide (DMSO) for cryopreservation, and incubated in the dark for between 30 minutes up to 2 hours at 37°C while gently being stirred. Tissue and supernatant were then loaded into a syringe and frozen at -80°C until EPR analysis. In our experiments, the EPR spectra were normalized with respect to tissue volume. Conducting experiments at liquid nitrogen temperature leads to some experimental advantages. The freezing of the spin adducts renders them stable over a longer period, which allows ample time to analyze tissue samples for ROS. The dielectric constant of ice is greatly reduced over its liquid counterpart; this property of water enables larger sample volumes to be inserted into the EPR cavity without overloading it and leads to enhanced signal detection. Due to Maxwell-Boltzmann statistics, the population difference goes up as the temperature goes down, so this phenomenon enhances the signal intensity as well. With the 'gold standard' assertion in mind, we investigated whether slicing tissue to assay ROS that is commonly used in fluorescence experiments will show more free radical generation than tissue of a similar volume that remains unsliced. Sliced tissue exhibited a 76% increase in ROS generation; this implies that higher ROS concentrations in sliced tissue indicate extraneous ROS generation not associated with the ROS stimulus of interest. We also investigated the role of ROS in chronic flow overload (CFO). Elevation of shear stress that increases production of vascular ROS has not been well investigated. We hypothesize that CFO increases ROS production mediated in part by NADPH oxidase, which leads to endothelial dysfunction. ROS production increased threefold in response to CFO. The endothelium dependent vasorelaxation was compromised in the CFO group. Treatment with apocynin significantly reduced ROS production in the vessel wall, preserved endothelial function, and inhibited expressions of p22/p47phox and NOX2/NOX4. The present data implicate NADPH oxidase produced ROS and eNOS uncoupling in endothelial dysfunction at 1 wk of CFO. In further work, a swine right ventricular hypertrophy (RVH) model induced by pulmonary artery (PA) banding was used to study right coronary artery (RCA) endothelial function and ROS level. Endothelial function was compromised in RCA of RVH as attributed to insufficient endothelial nitric oxide synthase cofactor tetrahydrobiopterin. In conclusion, stretch due to outward remodeling of RCA during RVH (at constant wall shear stress), similar to vessel stretch in hypertension, appears to induce ROS elevation, endothelial dysfunction, and an increase in basal tone. Finally, although hypertension-induced vascular stiffness and dysfunction are well established in patients and animal models, we hypothesize that stretch or distension due to hypertension and outward expansion is the cause of endothelial dysfunction mediated by angiotensin II type 1 (AT1) receptor in coronary arteries. The expression and activation of AT1 receptor and the production of ROS were up regulated and endothelial function deteriorated in the RCA. The acute inhibition of AT1 receptor and NADPH oxidase partially restored the endothelial function. Stretch or distension activates the AT1 receptor which mediates ROS production; this collectively leads to endothelial dysfunction in coronary arteries.

Organotypic Cultures from the Adult CNS: A Novel Model to Study Demyelination and Remyelination Ex Vivo.

PubMed

Tan, Glaiza A; Furber, Kendra L; Thangaraj, Merlin P; Sobchishin, LaRhonda; Doucette, J Ronald; Nazarali, Adil J

2018-01-01

Experimental models of multiple sclerosis (MS) have significantly advanced our understanding of pathophysiology and therapeutic interventions. Although in vivo rodent models are considered to most closely represent the complex cellular and molecular disease states of the human central nervous system (CNS), these can be costly to maintain and require long timelines. Organotypic slice cultures maintain the cytotypic organization observed in the intact CNS, yet provide many of the experimental advantages of in vitro cell culture models. Cerebellar organotypic cultures have proven useful for studying myelination and remyelination, but this model has only been established using early postnatal tissue. This young brain tissue allows for neuro development ex vivo to mimic the 'mature' CNS; however, there are many differences between postnatal and adult organotypic cultures. This may be particularly relevant to MS, as a major barrier to myelin regeneration is age. This paper describes a modified protocol to study demyelination and remyelination in adult cerebellar tissue, which has been used to demonstrate neuroprotection with omega-3 fatty acids. Thus, adult cerebellar organotypic cultures provide a novel ex vivo platform for screening potential therapies in myelin degeneration and repair.

TH-C-18A-11: Investigating the Minimum Scan Parameters Required to Generate Free-Breathing Fast-Helical CT Scans Without Motion-Artifacts

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

Thomas, D; Neylon, J; Dou, T

Purpose: A recently proposed 4D-CT protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artifacts, which arise when tissue motion is greater than scan speed. This work identifies the minimum scanner parameters required to successfully generate free-breathing fast-helical scans without doubling-artifacts. Methods: 10 patients were imaged under free breathing conditions 25 times in alternating directions with a 64-slice CT scanner using a low dose fast helical protocol. A high temporal resolution (0.1s) 4D-CT was generated using a patient specific motionmore » model and patient breathing waveforms, and used as the input for a scanner simulation. Forward projections were calculated using helical cone-beam geometry (800 projections per rotation) and a GPU accelerated reconstruction algorithm was implemented. Various CT scanner detector widths and rotation times were simulated, and verified using a motion phantom. Doubling-artifacts were quantified in patient images using structural similarity maps to determine the similarity between axial slices. Results: Increasing amounts of doubling-artifacts were observed with increasing rotation times > 0.2s for 16×1mm slice scan geometry. No significant increase in doubling artifacts was observed for 64×1mm slice scan geometry up to 1.0s rotation time although blurring artifacts were observed >0.6s. Using a 16×1mm slice scan geometry, a rotation time of less than 0.3s (53mm/s scan speed) would be required to produce images of similar quality to a 64×1mm slice scan geometry. Conclusion: The current generation of 16 slice CT scanners, which are present in most Radiation Oncology departments, are not capable of generating free-breathing sorting-artifact-free images in the majority of patients. The next generation of CT scanners should be capable of at least 53mm/s scan speed in order to use a fast-helical 4D-CT protocol to generate a motion-artifact free 4D-CT. NIH R01CA096679.« less

An approach for quantification of platinum distribution in tissues by LA-ICP-MS imaging using isotope dilution analysis.

PubMed

Moraleja, I; Mena, M L; Lázaro, A; Neumann, B; Tejedor, A; Jakubowski, N; Gómez-Gómez, M M; Esteban-Fernández, D

2018-02-01

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been revealed as a convenient technique for trace elemental imaging in tissue sections, providing elemental 2D distribution at a quantitative level. For quantification purposes, in the last years several approaches have been proposed in the literature such as the use of CRMs or matrix matched standards. The use of Isotope Dilution (ID) for quantification by LA-ICP-MS has been also described, being mainly useful for bulk analysis but not feasible for spatial measurements so far. In this work, a quantification method based on ID analysis was developed by printing isotope-enriched inks onto kidney slices from rats treated with antitumoral Pt-based drugs using a commercial ink-jet device, in order to perform an elemental quantification in different areas from bio-images. For the ID experiments 194 Pt enriched platinum was used. The methodology was validated by deposition of natural Pt standard droplets with a known amount of Pt onto the surface of a control tissue, where could be quantified even 50pg of Pt, with recoveries higher than 90%. The amount of Pt present in the whole kidney slices was quantified for cisplatin, carboplatin and oxaliplatin-treated rats. The results obtained were in accordance with those previously reported. The amount of Pt distributed between the medullar and cortical areas was also quantified, observing different behavior for the three drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Rat brain sagittal organotypic slice cultures as an ex vivo dopamine cell loss system.

PubMed

McCaughey-Chapman, Amy; Connor, Bronwen

2017-02-01

Organotypic brain slice cultures are a useful tool to study neurological function as they provide a more complex, 3-dimensional system than standard 2-dimensional in vitro cell cultures. Building on a previously developed mouse brain slice culture protocol, we have developed a rat sagittal brain slice culture system as an ex vivo model of dopamine cell loss. We show that rat brain organotypic slice cultures remain viable for up to 6 weeks in culture. Using Fluoro-Gold axonal tracing, we demonstrate that the slice 3-dimensional cytoarchitecture is maintained over a 4 week culturing period, with particular focus on the nigrostriatal pathway. Treatment of the cultures with 6-hydroxydopamine and desipramine induces a progressive loss of Fluoro-Gold-positive nigral cells with a sustained loss of tyrosine hydroxylase-positive nigral cells. This recapitulates the pattern of dopaminergic degeneration observed in the rat partial 6-hydroxydopamine lesion model and, most importantly, the progressive pathology of Parkinson's disease. Our slice culture platform provides an advance over other systems, as we demonstrate for the first time 3-dimensional cytoarchitecture maintenance of rat nigrostriatal sagittal slices for up to 6 weeks. Our ex vivo organotypic slice culture system provides a long term cellular platform to model Parkinson's disease, allowing for the elucidation of mechanisms involved in dopaminergic neuron degeneration and the capability to study cellular integration and plasticity ex vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

Using a high-speed movie camera to evaluate slice dropping in clinical image interpretation with stack mode viewers.

PubMed

Yakami, Masahiro; Yamamoto, Akira; Yanagisawa, Morio; Sekiguchi, Hiroyuki; Kubo, Takeshi; Togashi, Kaori

2013-06-01

The purpose of this study is to verify objectively the rate of slice omission during paging on picture archiving and communication system (PACS) viewers by recording the images shown on the computer displays of these viewers with a high-speed movie camera. This study was approved by the institutional review board. A sequential number from 1 to 250 was superimposed on each slice of a series of clinical Digital Imaging and Communication in Medicine (DICOM) data. The slices were displayed using several DICOM viewers, including in-house developed freeware and clinical PACS viewers. The freeware viewer and one of the clinical PACS viewers included functions to prevent slice dropping. The series was displayed in stack mode and paged in both automatic and manual paging modes. The display was recorded with a high-speed movie camera and played back at a slow speed to check whether slices were dropped. The paging speeds were also measured. With a paging speed faster than half the refresh rate of the display, some viewers dropped up to 52.4 % of the slices, while other well-designed viewers did not, if used with the correct settings. Slice dropping during paging was objectively confirmed using a high-speed movie camera. To prevent slice dropping, the viewer must be specially designed for the purpose and must be used with the correct settings, or the paging speed must be slower than half of the display refresh rate.

Lesion detection performance of cone beam CT images with anatomical background noise: single-slice vs. multi-slice human and model observer study

NASA Astrophysics Data System (ADS)

Han, Minah; Jang, Hanjoo; Baek, Jongduk

2018-03-01

We investigate lesion detectability and its trends for different noise structures in single-slice and multislice CBCT images with anatomical background noise. Anatomical background noise is modeled using a power law spectrum of breast anatomy. Spherical signal with a 2 mm diameter is used for modeling a lesion. CT projection data are acquired by the forward projection and reconstructed by the Feldkamp-Davis-Kress algorithm. To generate different noise structures, two types of reconstruction filters (Hanning and Ram-Lak weighted ramp filters) are used in the reconstruction, and the transverse and longitudinal planes of reconstructed volume are used for detectability evaluation. To evaluate single-slice images, the central slice, which contains the maximum signal energy, is used. To evaluate multislice images, central nine slices are used. Detectability is evaluated using human and model observer studies. For model observer, channelized Hotelling observer (CHO) with dense difference-of-Gaussian (D-DOG) channels are used. For all noise structures, detectability by a human observer is higher for multislice images than single-slice images, and the degree of detectability increase in multislice images depends on the noise structure. Variation in detectability for different noise structures is reduced in multislice images, but detectability trends are not much different between single-slice and multislice images. The CHO with D-DOG channels predicts detectability by a human observer well for both single-slice and multislice images.

Evaporation process in histological tissue sections for neutron autoradiography.

PubMed

Espector, Natalia M; Portu, Agustina; Santa Cruz, Gustavo A; Saint Martin, Gisela

2018-05-01

The analysis of the distribution and density of nuclear tracks forming an autoradiography in a nuclear track detector (NTD) allows the determination of 10 B atoms concentration and location in tissue samples from Boron Neutron Capture Therapy (BNCT) protocols. This knowledge is of great importance for BNCT dosimetry and treatment planning. Tissue sections studied with this technique are obtained by cryosectioning frozen tissue specimens. After the slicing procedure, the tissue section is put on the NTD and the sample starts drying. The thickness varies from its original value allowing more particles to reach the detector and, as the mass of the sample decreases, the boron concentration in the sample increases. So in order to determine the concentration present in the hydrated tissue, the application of corrective coefficients is required. Evaporation mechanisms as well as various factors that could affect the process of mass variation are outlined in this work. Mass evolution for tissue samples coming from BDIX rats was registered with a semimicro analytical scale and measurements were analyzed with software developed to that end. Ambient conditions were simultaneously recorded, obtaining reproducible evaporation curves. Mathematical models found in the literature were applied for the first time to this type of samples and the best fit of the experimental data was determined. The correlation coefficients and the variability of the parameters were evaluated, pointing to Page's model as the one that best represented the evaporation curves. These studies will contribute to a more precise assessment of boron concentration in tissue samples by the Neutron Autoradiography technique.

Browning in Apples: Exploring the Biochemical Basis of an Easily-Observable Phenotype

ERIC Educational Resources Information Center

Deutch, Charles E.

2018-01-01

Many fruits and vegetables undergo browning when they are cut and the tissue is exposed to the air. This is due to the activity of the enzyme polyphenol oxidase (PPO, EC 1.14.18.1) with endogenous substrates. In this laboratory experiment, students prepare slices of different varieties of apples and assess the rate of browning. They make a simple…

GABAergic transmission facilitates ictogenesis and synchrony between CA3, hilus, and dentate gyrus in slices from epileptic rats

PubMed Central

Gafurov, Boris

2013-01-01

The impact of regional hippocampal interactions and GABAergic transmission on ictogenesis remain unclear. Cortico-hippocampal slices from pilocarpine-treated epileptic rats were compared with controls to investigate associations between seizurelike events (SLE), GABAergic transmission, and neuronal synchrony within and between cortico-hippocampal regions. Multielectrode array recordings revealed more prevalent hippocampal SLE in epileptic tissue when excitatory transmission was enhanced and GABAergic transmission was intact [removal of Mg2+ (0Mg)] than when GABAergic transmission was blocked [removal of Mg2+ + bicuculline methiodide (0Mg+BMI)]. When activity within individual regions was analyzed, spectral and temporal slow oscillation/SLE correlations and cross-correlations were highest within the hilus of epileptic tissue during SLE but were similar in 0Mg and 0Mg+BMI. GABAergic facilitation of spectral “slow” oscillation and ripple correlations was most prominent within CA3 of epileptic tissue during SLE. When activity between regions was analyzed, slow oscillation and ripple coherence was highest between the hilus and dentate gyrus as well as between the hilus and CA3 of epileptic tissue during SLE and was significantly higher in 0Mg than 0Mg+BMI. High 0Mg-induced SLE cross-correlations between the hilus and dentate gyrus as well as between the hilus and CA3 were reduced or abolished in 0Mg+BMI. SLE cross-correlation lag measurements provided evidence for a monosynaptic connection from the hilus to the dentate gyrus during SLE. Findings implicate the hilus as an oscillation generator, whose impact on other cortico-hippocampal regions is mediated by GABAergic transmission. Data also suggest that GABAA receptor-mediated transmission facilitates back-propagation from CA3/hilus to the dentate gyrus and that this back-propagation augments SLE in epileptic hippocampus. PMID:23615549

Effect of simultaneous infrared dry-blanching and dehydration on quality characteristics of carrot slices

USDA-ARS?s Scientific Manuscript database

This study investigated the effects of various processing parameters on carrot slices exposed to infrared (IR) radiation heating for achieving simultaneous infrared dry-blanching and dehydration (SIRDBD). The investigated parameters were product surface temperature, slice thickness and processing ti...

Use of a thin-section archive and enterprise 3D software for long-term storage of thin-slice CT data sets.

PubMed

Meenan, Christopher; Daly, Barry; Toland, Christopher; Nagy, Paul

2006-01-01

Rapid advances are changing the technology and applications of multidetector computed tomography (CT) scanners. The major increase in data associated with this new technology, however, breaks most commercial picture archiving and communication system (PACS) architectures by preventing them from delivering data in real time to radiologists and outside clinicians. We proposed a phased model for 3D workflow, installed a thin-slice archive and measured thin-slice data storage over a period of 5 months. A mean of 1,869 CT studies were stored per month, with an average of 643 images per study and a mean total volume of 588 GB/month. We also surveyed 48 radiologists to determine diagnostic use, impressions of thin-slice value, and requirements for retention times. The majority of radiologists thought thin slice was helpful for diagnosis and regularly used the application. Permanent storage of thin slice CT is likely to become best practice and a mission-critical pursuit for the health care enterprise.

Human bone hardness seems to depend on tissue type but not on anatomical site in the long bones of an old subject.

PubMed

Ohman, Caroline; Zwierzak, Iwona; Baleani, Massimiliano; Viceconti, Marco

2013-02-01

It has been hypothesised that among different human subjects, the bone tissue quality varies as a function of the bone segment morphology. The aim of this study was to assess and compare the quality, evaluated in terms of hardness of packages of lamellae, of cortical and trabecular bones, at different anatomical sites within the human skeleton. The contralateral six long bones of an old human subject were indented at different levels along the diaphysis and at both epiphyses of each bone. Hardness value, which is correlated to the degree of mineralisation, of both cortical and trabecular bone tissues was calculated for each indentation location. It was found that the cortical bone tissue was harder (+18%) than the trabecular one. In general, the bone hardness was found to be locally highly heterogeneous. In fact, considering one single slice obtained for a bone segment, the coefficient of variation of the hardness values was up to 12% for cortical bone and up to 17% for trabecular bone. However, the tissue hardness was on average quite homogeneous within and among the long bones of the studied donor, although differences up to 9% among levels and up to 7% among bone segments were found. These findings seem not to support the mentioned hypothesis, at least not for the long bones of an old subject.

Detection of Post-Therapeutic Effects in Breast Carcinoma Using Hard X-Ray Index of Refraction Computed Tomography - A Feasibility Study.

PubMed

Grandl, Susanne; Sztrókay-Gaul, Anikó; Mittone, Alberto; Gasilov, Sergey; Brun, Emmanuel; Bravin, Alberto; Mayr, Doris; Auweter, Sigrid D; Hellerhoff, Karin; Reiser, Maximilian; Coan, Paola

2016-01-01

Neoadjuvant chemotherapy is the state-of-the-art treatment in advanced breast cancer. A correct visualization of the post-therapeutic tumor size is of high prognostic relevance. X-ray phase-contrast computed tomography (PC-CT) has been shown to provide improved soft-tissue contrast at a resolution formerly restricted to histopathology, at low doses. This study aimed at assessing ex-vivo the potential use of PC-CT for visualizing the effects of neoadjuvant chemotherapy on breast carcinoma. The analysis was performed on two ex-vivo formalin-fixed mastectomy samples containing an invasive carcinoma removed from two patients treated with neoadjuvant chemotherapy. Images were matched with corresponding histological slices. The visibility of typical post-therapeutic tissue changes was assessed and compared to results obtained with conventional clinical imaging modalities. PC-CT depicted the different tissue types with an excellent correlation to histopathology. Post-therapeutic tissue changes were correctly visualized and the residual tumor mass could be detected. PC-CT outperformed clinical imaging modalities in the detection of chemotherapy-induced tissue alterations including post-therapeutic tumor size. PC-CT might become a unique diagnostic tool in the prediction of tumor response to neoadjuvant chemotherapy. PC-CT might be used to assist during histopathological diagnosis, offering a high-resolution and high-contrast virtual histological tool for the accurate delineation of tumor boundaries.

Effects of Digested Onion Extracts on Intestinal Gene Expression: An Interspecies Comparison Using Different Intestine Models

PubMed Central

Govers, Coen; van der Meulen, Jan; van Hoef, Angeline; Stoopen, Geert; Hamers, Astrid; Hoekman, Arjan; de Vos, Ric; Bovee, Toine F. H.; Smits, Mari; Mes, Jurriaan J.

2016-01-01

Human intestinal tissue samples are barely accessible to study potential health benefits of nutritional compounds. Numbers of animals used in animal trials, however, need to be minimalized. Therefore, we explored the applicability of in vitro (human Caco-2 cells) and ex vivo intestine models (rat precision cut intestine slices and the pig in-situ small intestinal segment perfusion (SISP) technique) to study the effect of food compounds. In vitro digested yellow (YOd) and white onion extracts (WOd) were used as model food compounds and transcriptomics was applied to obtain more insight into which extent mode of actions depend on the model. The three intestine models shared 9,140 genes which were used to compare the responses to digested onions between the models. Unsupervised clustering analysis showed that genes up- or down-regulated by WOd in human Caco-2 cells and rat intestine slices were similarly regulated by YOd, indicating comparable modes of action for the two onion species. Highly variable responses to onion were found in the pig SISP model. By focussing only on genes with significant differential expression, in combination with a fold change > 1.5, 15 genes showed similar onion-induced expression in human Caco-2 cells and rat intestine slices and 2 overlapping genes were found between the human Caco-2 and pig SISP model. Pathway analyses revealed that mainly processes related to oxidative stress, and especially the Keap1-Nrf2 pathway, were affected by onions in all three models. Our data fit with previous in vivo studies showing that the beneficial effects of onions are mostly linked to their antioxidant properties. Taken together, our data indicate that each of the in vitro and ex vivo intestine models used in this study, taking into account their limitations, can be used to determine modes of action of nutritional compounds and can thereby reduce the number of animals used in conventional nutritional intervention studies. PMID:27631494

Effects of Digested Onion Extracts on Intestinal Gene Expression: An Interspecies Comparison Using Different Intestine Models.

PubMed

de Wit, Nicole J W; Hulst, Marcel; Govers, Coen; van der Meulen, Jan; van Hoef, Angeline; Stoopen, Geert; Hamers, Astrid; Hoekman, Arjan; de Vos, Ric; Bovee, Toine F H; Smits, Mari; Mes, Jurriaan J; Hendriksen, Peter J M

2016-01-01

Human intestinal tissue samples are barely accessible to study potential health benefits of nutritional compounds. Numbers of animals used in animal trials, however, need to be minimalized. Therefore, we explored the applicability of in vitro (human Caco-2 cells) and ex vivo intestine models (rat precision cut intestine slices and the pig in-situ small intestinal segment perfusion (SISP) technique) to study the effect of food compounds. In vitro digested yellow (YOd) and white onion extracts (WOd) were used as model food compounds and transcriptomics was applied to obtain more insight into which extent mode of actions depend on the model. The three intestine models shared 9,140 genes which were used to compare the responses to digested onions between the models. Unsupervised clustering analysis showed that genes up- or down-regulated by WOd in human Caco-2 cells and rat intestine slices were similarly regulated by YOd, indicating comparable modes of action for the two onion species. Highly variable responses to onion were found in the pig SISP model. By focussing only on genes with significant differential expression, in combination with a fold change > 1.5, 15 genes showed similar onion-induced expression in human Caco-2 cells and rat intestine slices and 2 overlapping genes were found between the human Caco-2 and pig SISP model. Pathway analyses revealed that mainly processes related to oxidative stress, and especially the Keap1-Nrf2 pathway, were affected by onions in all three models. Our data fit with previous in vivo studies showing that the beneficial effects of onions are mostly linked to their antioxidant properties. Taken together, our data indicate that each of the in vitro and ex vivo intestine models used in this study, taking into account their limitations, can be used to determine modes of action of nutritional compounds and can thereby reduce the number of animals used in conventional nutritional intervention studies.

Neural network classification technique and machine vision for bread crumb grain evaluation

NASA Astrophysics Data System (ADS)

Zayas, Inna Y.; Chung, O. K.; Caley, M.

1995-10-01

Bread crumb grain was studied to develop a model for pattern recognition of bread baked at Hard Winter Wheat Quality Laboratory (HWWQL), Grain Marketing and Production Research Center (GMPRC). Images of bread slices were acquired with a scanner in a 512 multiplied by 512 format. Subimages in the central part of the slices were evaluated by several features such as mean, determinant, eigen values, shape of a slice and other crumb features. Derived features were used to describe slices and loaves. Neural network programs of MATLAB package were used for data analysis. Learning vector quantization method and multivariate discriminant analysis were applied to bread slices from what of different sources. A training and test sets of different bread crumb texture classes were obtained. The ranking of subimages was well correlated with visual judgement. The performance of different models on slice recognition rate was studied to choose the best model. The recognition of classes created according to human judgement with image features was low. Recognition of arbitrarily created classes, according to porosity patterns, with several feature patterns was approximately 90%. Correlation coefficient was approximately 0.7 between slice shape features and loaf volume.

Fast wavefront optimization for focusing through biological tissue (Conference Presentation)

NASA Astrophysics Data System (ADS)

Blochet, Baptiste; Bourdieu, Laurent; Gigan, Sylvain

2017-02-01

The propagation of light in biological tissues is rapidly dominated by multiple scattering: ballistic light is exponentially attenuated, which limits the penetration depth of conventional microscopy techniques. For coherent light, the recombination of the different scattered paths creates a complex interference: speckle. Recently, different wavefront shaping techniques have been developed to coherently manipulate the speckle. It opens the possibility to focus light through complex media and ultimately to image in them, provided however that the medium can be considered as stationary. We have studied the possibility to focus in and through time-varying biological tissues. Their intrinsic temporal dynamics creates a fast decorrelation of the speckle pattern. Therefore, focusing through biological tissues requires fast wavefront shaping devices, sensors and algorithms. We have investigated the use of a MEMS-based spatial light modulator (SLM) and a fast photodetector, combined with FPGA electronics to implement a closed-loop optimization. Our optimization process is just limited by the temporal dynamics of the SLM (200µs) and the computation time (45µs), thus corresponding to a rate of 4 kHz. To our knowledge, it's the fastest closed loop optimization using phase modulators. We have studied the focusing through colloidal solutions of TiO2 particles in glycerol, allowing tunable temporal stability, and scattering properties similar to biological tissues. We have shown that our set-up fulfills the required characteristics (speed, enhancement) to focus through biological tissues. We are currently investigating the focusing through acute rat brain slices and the memory effect in dynamic scattering media.

In situ analysis of plant tissue underivatized carbohydrates and on-probe enzymatic degraded starch by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry by using carbon nanotubes as matrix.

PubMed

Gholipour, Yousef; Nonami, Hiroshi; Erra-Balsells, Rosa

2008-12-15

Underivatized carbohydrates of tulip bulb and leaf tissues were characterized in situ by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) by using carbon nanotubes (CNTs) as matrix. Two sample preparation methods--(i) depositing CNTs on the fresh tissue slices placed on the probe and (ii) locating semitransparent tissues on a dried layer of CNTs on the probe--were examined. Furthermore, practicability of in situ starch analysis by MALDI-TOF MS was examined by detection of glucose originated from on-probe amyloglucosidase-catalyzed degradation of starch on the tissue surface. Besides, CNTs could efficiently desorb/ionize natural mono-, di-, and oligosaccharides extracted from tulip bulb tissues as well as glucose resulting from starch enzymatic degradation in vitro. These results were compared with those obtained by in situ MALDI-TOF MS analysis of similar tissues. Positive ion mode showed superior signal reproducibility. CNTs deposited under semitransparent tissue could also desorb/ionize neutral carbohydrates, leading to nearly complete elimination of matrix cluster signals but with an increase in tissue-originated signals. Furthermore, several experiments were carried out to compare the efficiency of 2,5-dihydroxybenzoic acid, nor-harmane, alpha-cyano-4-hydroxycinnamic acid, and CNTs as matrices for MALDI of neutral carbohydrates from the intact plant tissue surface and for enzymatic tissue starch degradation; these results are discussed in brief. Among matrices studied, the lowest laser power was needed to acquire carbohydrate signals with high signal-to-noise ratio and resolution when CNTs were used.

Imaging of zymogen granules in fully wet cells: evidence for restricted mechanism of granule growth.

PubMed

Hammel, Ilan; Anaby, Debbie

2007-09-01

The introduction of wet SEM imaging technology permits electron microscopy of wet samples. Samples are placed in sealed specimen capsules and are insulated from the vacuum in the SEM chamber by an impermeable, electron-transparent membrane. The complete insulation of the sample from the vacuum allows direct imaging of fully hydrated, whole-mount tissue. In the current work, we demonstrate direct inspection of thick pancreatic tissue slices (above 400 mum). In the case of scanning of the pancreatic surface, the boundaries of intracellular features are seen directly. Thus no unfolding is required to ascertain the actual particle size distribution based on the sizes of the sections. This method enabled us to investigate the true granule size distribution and confirm early studies of improved conformity to a Poisson-like distribution, suggesting that the homotypic granule growth results from a mechanism, which favors the addition of a single unit granule to mature granules.

Indian hedgehog contributes to human cartilage endplate degeneration.

PubMed

Wang, Shaowei; Yang, Kun; Chen, Shuai; Wang, Jiying; Du, Guoqing; Fan, Shunwu; Wei, Lei

2015-08-01

To determine the role of Indian hedgehog (Ihh) signaling in human cartilage endplate (CEP) degeneration. CEP-degenerated tissues from patients with Modic I or II changes (n = 9 and 45, respectively) and normal tissues from vertebral burst fracture patients (n = 17) were collected. Specimens were either cut into slices for organ culture ex vivo or digested to isolate chondrocytes for cell culture in vitro. Ihh expression and the effect of Ihh on cartilage degeneration were determined by investigating degeneration markers in this study. Ihh expression and cartilage degeneration markers significantly increased in the Modic I and II groups. The expression of cartilage degeneration markers was positively correlated with degeneration severity. Gain-of-function for Ihh promoted expression of cartilage degeneration markers in vitro, while loss-of-function for Ihh inhibited their expression both in vitro and ex vivo. These findings demonstrated that Ihh promotes CEP degeneration. Blocking Ihh pathway has potential clinical usage for attenuating CEP degeneration.

Physiological Effects of Enriched Environment Exposure and LTP Induction in the Hippocampus In Vivo Do Not Transfer Faithfully to In Vitro Slices

ERIC Educational Resources Information Center

Eckert, Michael J.; Abraham, Wickliffe C.

2010-01-01

A number of experimental paradigms use in vitro brain slices to test for changes in synaptic transmission and plasticity following a behavioral manipulation. For example, a number of previous studies have reported a variety of effects of environmental enrichment (EE) exposure on field potential responses in hippocampal slices, but in no study was…

Comparative lung toxicity of engineered nanomaterials utilizing in vitro, ex vivo and in vivo approaches.

PubMed

Kim, Yong Ho; Boykin, Elizabeth; Stevens, Tina; Lavrich, Katelyn; Gilmour, M Ian

2014-11-26

Although engineered nanomaterials (ENM) are currently regulated either in the context of a new chemical, or as a new use of an existing chemical, hazard assessment is still to a large extent reliant on information from historical toxicity studies of the parent compound, and may not take into account special properties related to the small size and high surface area of ENM. While it is important to properly screen and predict the potential toxicity of ENM, there is also concern that current toxicity tests will require even heavier use of experimental animals, and reliable alternatives should be developed and validated. Here we assessed the comparative respiratory toxicity of ENM in three different methods which employed in vivo, in vitro and ex vivo toxicity testing approaches. Toxicity of five ENM (SiO2 (10), CeO2 (23), CeO2 (88), TiO2 (10), and TiO2 (200); parentheses indicate average ENM diameter in nm) were tested in this study. CD-1 mice were exposed to the ENM by oropharyngeal aspiration at a dose of 100 μg. Mouse lung tissue slices and alveolar macrophages were also exposed to the ENM at concentrations of 22-132 and 3.1-100 μg/mL, respectively. Biomarkers of lung injury and inflammation were assessed at 4 and/or 24 hr post-exposure. Small-sized ENM (SiO2 (10), CeO2 (23), but not TiO2 (10)) significantly elicited pro-inflammatory responses in mice (in vivo), suggesting that the observed toxicity in the lungs was dependent on size and chemical composition. Similarly, SiO2 (10) and/or CeO2 (23) were also more toxic in the lung tissue slices (ex vivo) and alveolar macrophages (in vitro) compared to other ENM. A similar pattern of inflammatory response (e.g., interleukin-6) was observed in both ex vivo and in vitro when a dose metric based on cell surface area (μg/cm(2)), but not culture medium volume (μg/mL) was employed. Exposure to ENM induced acute lung inflammatory effects in a size- and chemical composition-dependent manner. The cell culture and lung slice techniques provided similar profiles of effect and help bridge the gap in our understanding of in vivo, ex vivo, and in vitro toxicity outcomes.

Quantitative analysis of circadian single cell oscillations in response to temperature

PubMed Central

Kramer, Achim; Herzel, Hanspeter

2018-01-01

Body temperature rhythms synchronize circadian oscillations in different tissues, depending on the degree of cellular coupling: the responsiveness to temperature is higher when single circadian oscillators are uncoupled. So far, the role of coupling in temperature responsiveness has only been studied in organotypic tissue slices of the central circadian pacemaker, because it has been assumed that peripheral target organs behave like uncoupled multicellular oscillators. Since recent studies indicate that some peripheral tissues may exhibit cellular coupling as well, we asked whether peripheral network dynamics also influence temperature responsiveness. Using a novel technique for long-term, high-resolution bioluminescence imaging of primary cultured cells, exposed to repeated temperature cycles, we were able to quantitatively measure period, phase, and amplitude of central (suprachiasmatic nuclei neuron dispersals) and peripheral (mouse ear fibroblasts) single cell oscillations in response to temperature. Employing temperature cycles of different lengths, and different cell densities, we found that some circadian characteristics appear cell-autonomous, e.g. period responses, while others seem to depend on the quality/degree of cellular communication, e.g. phase relationships, robustness of the oscillation, and amplitude. Overall, our findings indicate a strong dependence on the cell’s ability for intercellular communication, which is not only true for neuronal pacemakers, but, importantly, also for cells in peripheral tissues. Hence, they stress the importance of comparative studies that evaluate the degree of coupling in a given tissue, before it may be used effectively as a target for meaningful circadian manipulation. PMID:29293562

Activatable Fluorescence Probe via Self-Immolative Intramolecular Cyclization for Histone Deacetylase Imaging in Live Cells and Tissues.

PubMed

Liu, Xianjun; Xiang, Meihao; Tong, Zongxuan; Luo, Fengyan; Chen, Wen; Liu, Feng; Wang, Fenglin; Yu, Ru-Qin; Jiang, Jian-Hui

2018-05-01

Histone deacetylases (HDACs) play essential roles in transcription regulation and are valuable theranostic targets. However, there are no activatable fluorescent probes for imaging of HDAC activity in live cells. Here, we develop for the first time a novel activatable two-photon fluorescence probe that enables in situ imaging of HDAC activity in living cells and tissues. The probe is designed by conjugating an acetyl-lysine mimic substrate to a masked aldehyde-containing fluorophore via a cyanoester linker. Upon deacetylation by HDAC, the probe undergoes a rapid self-immolative intramolecular cyclization reaction, producing a cyanohydrin intermediate that is spontaneously rapidly decomposed into the highly fluorescent aldehyde-containing two-photon fluorophore. The probe is shown to exhibit high sensitivity, high specificity, and fast response for HDAC detection in vitro. Imaging studies reveal that the probe is able to directly visualize and monitor HDAC activity in living cells. Moreover, the probe is demonstrated to have the capability of two-photon imaging of HDAC activity in deep tissue slices up to 130 μm. This activatable fluorescent probe affords a useful tool for evaluating HDAC activity and screening HDAC-targeting drugs in both live cell and tissue assays.

Estimation of regional gas and tissue volumes of the lung in supine man using computed tomography.

PubMed

Denison, D M; Morgan, M D; Millar, A B

1986-08-01

This study was intended to discover how well computed tomography could recover the volume and weight of lung like foams in a body like shell, and then how well it could recover the volume and weight of the lungs in supine man. Model thoraces were made with various loaves of bread submerged in water. Computed tomography scans recovered the volume of the model lungs (true volume range 250-12,500 ml) within +0.2 (SD 68) ml and their weights (true range 72-3125 g) within +30 (78) g. Scans also recovered successive injections of 50 ml of water, within +/- 5 ml. Scans in 12 healthy supine men recovered their vital capacities, total lung capacities (TLC), and predicted tissue volumes with comparable accuracy. At total lung capacity the mean tissue volume of single lungs was 431 (64) ml and at residual volume (RV) it was 427 (63) ml. Tissue volume was then used to match inspiratory and expiratory slices and calculate regional ventilation. Throughout the mid 90% of lung the RV/TLC ratio was fairly constant--mean 21% (5%). New methods of presenting such regional data graphically and automatically are also described.

Organotypic slice cultures containing the preBötzinger complex generate respiratory-like rhythms

PubMed Central

Phillips, Wiktor S.; Herly, Mikkel; Del Negro, Christopher A.

2015-01-01

Study of acute brain stem slice preparations in vitro has advanced our understanding of the cellular and synaptic mechanisms of respiratory rhythm generation, but their inherent limitations preclude long-term manipulation and recording experiments. In the current study, we have developed an organotypic slice culture preparation containing the preBötzinger complex (preBötC), the core inspiratory rhythm generator of the ventrolateral brain stem. We measured bilateral synchronous network oscillations, using calcium-sensitive fluorescent dyes, in both ventrolateral (presumably the preBötC) and dorsomedial regions of slice cultures at 7–43 days in vitro. These calcium oscillations appear to be driven by periodic bursts of inspiratory neuronal activity, because whole cell recordings from ventrolateral neurons in culture revealed inspiratory-like drive potentials, and no oscillatory activity was detected from glial fibrillary associated protein-expressing astrocytes in cultures. Acute slices showed a burst frequency of 10.9 ± 4.2 bursts/min, which was not different from that of brain stem slice cultures (13.7 ± 10.6 bursts/min). However, slice cocultures that include two cerebellar explants placed along the dorsolateral border of the brainstem displayed up to 193% faster burst frequency (22.4 ± 8.3 bursts/min) and higher signal amplitude (340%) compared with acute slices. We conclude that preBötC-containing slice cultures retain inspiratory-like rhythmic function and therefore may facilitate lines of experimentation that involve extended incubation (e.g., genetic transfection or chronic drug exposure) while simultaneously being amenable to imaging and electrophysiology at cellular, synaptic, and network levels. PMID:26655824

Lysyl Oxidase-Like 1 Protein Deficiency Protects Mice from Adenoviral Transforming Growth Factor-β1-induced Pulmonary Fibrosis.

PubMed

Bellaye, Pierre-Simon; Shimbori, Chiko; Upagupta, Chandak; Sato, Seidai; Shi, Wei; Gauldie, Jack; Ask, Kjetil; Kolb, Martin

2018-04-01

Idiopathic pulmonary fibrosis (IPF) is a progressive disease characterized by excessive deposition of extracellular matrix (ECM) in the lung parenchyma. The abnormal ECM deposition slowly overtakes normal lung tissue, disturbing gas exchange and leading to respiratory failure and death. ECM cross-linking and subsequent stiffening is thought to be a major contributor of disease progression and also promotes the activation of transforming growth factor (TGF)-β1, one of the main profibrotic growth factors. Lysyl oxidase-like (LOXL) 1 belongs to the cross-linking enzyme family and has been shown to be up-regulated in active fibrotic regions of bleomycin-treated mice and patients with IPF. We demonstrate in this study that LOXL1-deficient mice are protected from experimental lung fibrosis induced by overexpression of TGF-β1 using adenoviral (Ad) gene transfer (AdTGF-β1). The lack of LOXL1 prevented accumulation of insoluble cross-linked collagen in the lungs, and therefore limited lung stiffness after AdTGF-β1. In addition, we applied mechanical stretch to lung slices from LOXL1 +/+ and LOXL1 -/- mice treated with AdTGF-β1. Lung stiffness (Young's modulus) of LOXL1 -/- lung slices was significantly lower compared with LOXL1 +/+ lung slices. Moreover, the release of activated TGF-β1 after mechanical stretch was significantly lower in LOXL1 -/- mice compared with LOXL1 +/+ mice after AdTGF-β1. These data support the concept that cross-linking enzyme inhibition represents an interesting therapeutic target for drug development in IPF.

The neurotrophin-inducible gene Vgf regulates hippocampal function and behavior through a brain-derived neurotrophic factor-dependent mechanism.

PubMed

Bozdagi, Ozlem; Rich, Erin; Tronel, Sophie; Sadahiro, Masato; Patterson, Kamara; Shapiro, Matthew L; Alberini, Cristina M; Huntley, George W; Salton, Stephen R J

2008-09-24

VGF is a neurotrophin-inducible, activity-regulated gene product that is expressed in CNS and PNS neurons, in which it is processed into peptides and secreted. VGF synthesis is stimulated by BDNF, a critical regulator of hippocampal development and function, and two VGF C-terminal peptides increase synaptic activity in cultured hippocampal neurons. To assess VGF function in the hippocampus, we tested heterozygous and homozygous VGF knock-out mice in two different learning tasks, assessed long-term potentiation (LTP) and depression (LTD) in hippocampal slices from VGF mutant mice, and investigated how VGF C-terminal peptides modulate synaptic plasticity. Treatment of rat hippocampal slices with the VGF-derived peptide TLQP62 resulted in transient potentiation through a mechanism that was selectively blocked by the BDNF scavenger TrkB-Fc, the Trk tyrosine kinase inhibitor K252a (100 nm), and tPA STOP, an inhibitor of tissue plasminogen activator (tPA), an enzyme involved in pro-BDNF cleavage to BDNF, but was not blocked by the NMDA receptor antagonist APV, anti-p75(NTR) function-blocking antiserum, or previous tetanic stimulation. Although LTP was normal in slices from VGF knock-out mice, LTD could not be induced, and VGF mutant mice were impaired in hippocampal-dependent spatial learning and contextual fear conditioning tasks. Our studies indicate that the VGF C-terminal peptide TLQP62 modulates hippocampal synaptic transmission through a BDNF-dependent mechanism and that VGF deficiency in mice impacts synaptic plasticity and memory in addition to depressive behavior.

The Neurotrophin-Inducible Gene Vgf Regulates Hippocampal Function and Behavior Through a BDNF-Dependent Mechanism

PubMed Central

Bozdagi, Ozlem; Rich, Erin; Tronel, Sophie; Sadahiro, Masato; Patterson, Kamara; Shapiro, Matthew L.; Alberini, Cristina M.; Huntley, George W.; Salton, Stephen R. J.

2009-01-01

VGF is a neurotrophin-inducible, activity-regulated gene product that is expressed in CNS and PNS neurons, where it is processed into peptides and secreted. VGF synthesis is stimulated by BDNF, a critical regulator of hippocampal development and function, and two VGF C-terminal peptides increase synaptic activity in cultured hippocampal neurons. To assess VGF function in the hippocampus, we tested heterozygous and homozygous VGF knockout mice in two different learning tasks, assessed long-term potentiation (LTP) and depression (LTD) in hippocampal slices from VGF mutant mice, and investigated how VGF C-terminal peptides modulate synaptic plasticity. Treatment of rat hippocampal slices with the VGF-derived peptide TLQP62 resulted in transient potentiation through a mechanism that was selectively blocked by the BDNF scavenger TrkB-Fc, the Trk tyrosine kinase inhibitor K252a (100 nM), and by tPASTOP, an inhibitor of tissue plasminogen activator (tPA), an enzyme involved in pro-BDNF cleavage to BDNF, but was not blocked by the NMDA receptor antagonist APV, anti-p75NTR function-blocking antiserum, nor by prior tetanic stimulation. Although LTP was normal in slices from VGF knockout mice, LTD could not be induced, and VGF mutant mice were impaired in hippocampal-dependent spatial learning and contextual fear conditioning tasks. Our studies indicate that the VGF C-terminal peptide TLQP62 modulates hippocampal synaptic transmission through a BDNF-dependent mechanism, and that VGF deficiency in mice impacts synaptic plasticity and memory in addition to depressive behavior. PMID:18815270

Nanoscale chromatin structure characterization for optical applications: a transmission electron microscopy study (Conference Presentation)

NASA Astrophysics Data System (ADS)

Li, Yue; Cherkezyan, Lusik; Zhang, Di; Almassalha, Luay; Roth, Eric; Chandler, John; Bleher, Reiner; Subramanian, Hariharan; Dravid, Vinayak P.; Backman, Vadim

2017-02-01

Structural and biological origins of light scattering in cells and tissue are still poorly understood. We demonstrate how this problem might be addressed through the use of transmission electron microscopy (TEM). For biological samples, TEM image intensity is proportional to mass-density, and thus proportional to refractive index (RI). By calculating the autocorrelation function (ACF) of TEM image intensity of a thin-section of cells, we essentially maintain the nanoscale ACF of the 3D cellular RI distribution, given that the RI distribution is statistically isotropic. Using this nanoscale 3D RI ACF, we can simulate light scattering through biological samples, and thus guiding many optical techniques to quantify specific structures. In this work, we chose to use Partial Wave Spectroscopy (PWS) microscopy as a one of the nanoscale-sensitive optical techniques. Hela cells were prepared using standard protocol to preserve nanoscale ultrastructure, and a 50-nm slice was sectioned for TEM imaging at 6 nm resolution. The ACF was calculated for chromatin, and the PWS mean sigma was calculated by summing over the power spectral density in the visible light frequency of a random medium generated to match the ACF. A 1-µm slice adjacent to the 50-nm slice was sectioned for PWS measurement to guarantee identical chromatin structure. For 33 cells, we compared the calculated PWS mean sigma from TEM and the value measured directly, and obtained a strong correlation of 0.69. This example indicates the great potential of using TEM measured RI distribution to better understand the quantification of cellular nanostructure by optical methods.

3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy

NASA Astrophysics Data System (ADS)

Gimenez, Y.; Busser, B.; Trichard, F.; Kulesza, A.; Laurent, J. M.; Zaun, V.; Lux, F.; Benoit, J. M.; Panczer, G.; Dugourd, P.; Tillement, O.; Pelascini, F.; Sancey, L.; Motto-Ros, V.

2016-07-01

Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy, and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications.

3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy.

PubMed

Gimenez, Y; Busser, B; Trichard, F; Kulesza, A; Laurent, J M; Zaun, V; Lux, F; Benoit, J M; Panczer, G; Dugourd, P; Tillement, O; Pelascini, F; Sancey, L; Motto-Ros, V

2016-07-20

Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy, and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications.

3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy

PubMed Central

Gimenez, Y.; Busser, B.; Trichard, F.; Kulesza, A.; Laurent, J. M.; Zaun, V.; Lux, F.; Benoit, J. M.; Panczer, G.; Dugourd, P.; Tillement, O.; Pelascini, F.; Sancey, L.; Motto-Ros, V.

2016-01-01

Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy, and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications. PMID:27435424

Application of machine learning methodology for pet-based definition of lung cancer

PubMed Central

Kerhet, A.; Small, C.; Quon, H.; Riauka, T.; Schrader, L.; Greiner, R.; Yee, D.; McEwan, A.; Roa, W.

2010-01-01

We applied a learning methodology framework to assist in the threshold-based segmentation of non-small-cell lung cancer (nsclc) tumours in positron-emission tomography–computed tomography (pet–ct) imaging for use in radiotherapy planning. Gated and standard free-breathing studies of two patients were independently analysed (four studies in total). Each study had a pet–ct and a treatment-planning ct image. The reference gross tumour volume (gtv) was identified by two experienced radiation oncologists who also determined reference standardized uptake value (suv) thresholds that most closely approximated the gtv contour on each slice. A set of uptake distribution-related attributes was calculated for each pet slice. A machine learning algorithm was trained on a subset of the pet slices to cope with slice-to-slice variation in the optimal suv threshold: that is, to predict the most appropriate suv threshold from the calculated attributes for each slice. The algorithm’s performance was evaluated using the remainder of the pet slices. A high degree of geometric similarity was achieved between the areas outlined by the predicted and the reference suv thresholds (Jaccard index exceeding 0.82). No significant difference was found between the gated and the free-breathing results in the same patient. In this preliminary work, we demonstrated the potential applicability of a machine learning methodology as an auxiliary tool for radiation treatment planning in nsclc. PMID:20179802

Development of tolerance to the effects of vigabatrin (gamma-vinyl-GABA) on GABA release from rat cerebral cortex, spinal cord and retina.

PubMed Central

Neal, M. J.; Shah, M. A.

1990-01-01

1. The effects of acute and chronic vigabatrin (gamma-vinyl-GABA) (GVG) administration on gamma-aminobutyric acid (GABA) levels and release in rat cortical slices, spinal cord slices and retinas were studied. 2. GVG (250 mgkg-1 i.p.) administered to rats 18 h before death (acute administration) produced an almost 3 fold increase in GABA levels of the cortex and spinal cord and a 6 fold increase in retinal GABA. The levels of glutamate, aspartate, glycine and taurine were unaffected. 3. When GVG (250 mgkg-1 i.p.) was administered daily for 17 days (chronic administration) a similar (almost 3 fold) increase in cortical GABA occurred but the increases in spinal and retinal GABA were reduced by approximately 40%. 4. Acute administration of GVG strikingly increased the potassium-evoked release (KCl 50 mM) of GABA from all three tissues. This enhanced evoked release was reduced by about 50% in tissues taken from rats that had been chronically treated with GVG. 5. Acute administration of GVG reduced GABA-transaminase (GABA-T) activity by approximately 80% in cortex and cord and by 98% in the retina. Following the chronic administration of GVG, there was a trend for GABA-T activities to recover (significant only in cortex). Acute administration of GVG had no effect on glutamic acid decarboxylase (GAD) activity in cortex or spinal cord. However, chronic treatment resulted in significant decreases in GAD activity in both the cortex and cord (35% and 50% reduction respectively).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2379037

Breast percent density estimation from 3D reconstructed digital breast tomosynthesis images

NASA Astrophysics Data System (ADS)

Bakic, Predrag R.; Kontos, Despina; Carton, Ann-Katherine; Maidment, Andrew D. A.

2008-03-01

Breast density is an independent factor of breast cancer risk. In mammograms breast density is quantitatively measured as percent density (PD), the percentage of dense (non-fatty) tissue. To date, clinical estimates of PD have varied significantly, in part due to the projective nature of mammography. Digital breast tomosynthesis (DBT) is a 3D imaging modality in which cross-sectional images are reconstructed from a small number of projections acquired at different x-ray tube angles. Preliminary studies suggest that DBT is superior to mammography in tissue visualization, since superimposed anatomical structures present in mammograms are filtered out. We hypothesize that DBT could also provide a more accurate breast density estimation. In this paper, we propose to estimate PD from reconstructed DBT images using a semi-automated thresholding technique. Preprocessing is performed to exclude the image background and the area of the pectoral muscle. Threshold values are selected manually from a small number of reconstructed slices; a combination of these thresholds is applied to each slice throughout the entire reconstructed DBT volume. The proposed method was validated using images of women with recently detected abnormalities or with biopsy-proven cancers; only contralateral breasts were analyzed. The Pearson correlation and kappa coefficients between the breast density estimates from DBT and the corresponding digital mammogram indicate moderate agreement between the two modalities, comparable with our previous results from 2D DBT projections. Percent density appears to be a robust measure for breast density assessment in both 2D and 3D x-ray breast imaging modalities using thresholding.

Visualising the procedures in the influence of water on the ablation of dental hard tissue with erbium:yttrium-aluminium-garnet and erbium, chromium:yttrium-scandium-gallium-garnet laser pulses.

PubMed

Mir, Maziar; Gutknecht, Norbert; Poprawe, Reinhart; Vanweersch, Leon; Lampert, Friedrich

2009-05-01

The exact mechanism of the ablation of tooth hard tissue with most common wavelengths, which are 2,940 nm and 2,780 nm, is not yet clear. There are several different theories, but none of them has yet been established. Concepts and methods of looking at these mechanisms have been based on heat formation and transformation, and mathematical calculations evaluating the outcome of ablation, such as looking at the shape of cuts. This study provides a new concept, which is the monitoring of the direct interactions between laser light, water and enamel, with a high-speed camera. For this purpose, both the above-mentioned wavelengths were examined. Bovine anterior teeth were prepared as thin slices. Each imaged slice had a thickness close to that of the beam diameter so that the ablation effect could be shown in two dimensional pictures. The single images were extracted from the video-clips and then were animated. The following steps, explaining the ablation procedures during each pulse, were seen and reported: (1) low-output energy intensity in the first pulses that did not lead to an ablative effect; (2) bubble formation with higher output energy density; (3) the tooth surface during the pulse was covered with the plume of vapour (comparable with a cloud), and the margins of ablation on the tooth were not clear; (4) when the vapour bubble (cloud) was collapsing, an additional ablative process at the surface could be seen.

Parkia pendula lectin as histochemistry marker for meningothelial tumour.

PubMed

Beltrão, E I C; Medeiros, P L; Rodrigues, O G; Figueredo-Silva, J; Valença, M M; Coelho, L C B B; Carvalho, L B

2003-01-01

Lectins have been intensively used in histochemical techniques for cell surface characterization. These proteins are involved in several biological processes and their use as histochemical markers have been evaluated since they can indicate differences in cell surfaces. Parkia pendula lectin (PpeL) was evaluated as histochemical marker for meningothelial meningioma biopsies. Tissue slices were incubated with PpeL conjugated to horseradish peroxidase (PpeL-HRP) and Concanavalin A-HRP (ConA-HPR) and the binding visualized with diaminobenzidine and hydrogen peroxide. The lectin-tissue binding was inhibited with D-glucose. PpeL showed to be a useful tool for the characterization of meningothelial tumour and clinico-pathological diagnosis.

Regional Mapping of Gas Uptake by Blood and Tissue in the Human Lung using Hyperpolarized Xenon-129 MRI

PubMed Central

Qing, Kun; Ruppert, Kai; Jiang, Yun; Mata, Jaime F.; Miller, G. Wilson; Shim, Y. Michael; Wang, Chengbo; Ruset, Iulian C.; Hersman, F. William; Altes, Talissa A.; Mugler, John P.

2013-01-01

Purpose To develop a breath-hold acquisition for regional mapping of ventilation and the fractions of hyperpolarized xenon-129 (Xe129) dissolved in tissue (lung parenchyma and plasma) and red blood cells (RBCs), and to perform an exploratory study to characterize data obtained in human subjects. Materials and Methods A three-dimensional, multi-echo, radial-trajectory pulse sequence was developed to obtain ventilation (gaseous Xe129), tissue and RBC images in healthy subjects, smokers and asthmatics. Signal ratios (total dissolved Xe129 to gas, tissue-to-gas, RBC-to-gas and RBC-to-tissue) were calculated from the images for quantitative comparison. Results Healthy subjects demonstrated generally uniform values within coronal slices, and a gradient in values along the anterior-to-posterior direction. In contrast, images and associated ratio maps in smokers and asthmatics were generally heterogeneous and exhibited values mostly lower than those in healthy subjects. Whole-lung values of total dissolved Xe129 to gas, tissue-to-gas, and RBC-to-gas ratios in healthy subjects were significantly larger than those in diseased subjects. Conclusion Regional maps of tissue and RBC fractions of dissolved Xe129 were obtained from a short breath-hold acquisition, well tolerated by healthy volunteers and subjects with obstructive lung disease. Marked differences were observed in spatial distributions and overall amounts of Xe129 dissolved in tissue and RBCs among healthy subjects, smokers and asthmatics. PMID:23681559

Confocal multispot microscope for fast and deep imaging in semicleared tissues

NASA Astrophysics Data System (ADS)

Adam, Marie-Pierre; Müllenbroich, Marie Caroline; Di Giovanna, Antonino Paolo; Alfieri, Domenico; Silvestri, Ludovico; Sacconi, Leonardo; Pavone, Francesco Saverio

2018-02-01

Although perfectly transparent specimens are imaged faster with light-sheet microscopy, less transparent samples are often imaged with two-photon microscopy leveraging its robustness to scattering; however, at the price of increased acquisition times. Clearing methods that are capable of rendering strongly scattering samples such as brain tissue perfectly transparent specimens are often complex, costly, and time intensive, even though for many applications a slightly lower level of tissue transparency is sufficient and easily achieved with simpler and faster methods. Here, we present a microscope type that has been geared toward the imaging of semicleared tissue by combining multispot two-photon excitation with rolling shutter wide-field detection to image deep and fast inside semicleared mouse brain. We present a theoretical and experimental evaluation of the point spread function and contrast as a function of shutter size. Finally, we demonstrate microscope performance in fixed brain slices by imaging dendritic spines up to 400-μm deep.

Express diagnostics of intact and pathological dental hard tissues by optical PNC method

NASA Astrophysics Data System (ADS)

Masychev, Victor I.; Alexandrov, Michail T.

2000-03-01

The results of hard tooth tissues research by the optical PNC- method in experimental and clinical conditions are presented. In the experiment under 90 test-sample of tooth slices with thickness about 1 mm (enamel, dentine and cement) were researched. The results of the experiment were processed by the method of correlation analyze. Clinical researches were executed on teeth of 210 patients. The regions of tooth tissue diseases with initial, moderate and deep caries were investigated. Spectral characteristics of intact and pathologically changed tooth tissues are presented and their peculiar features are discussed. The results the optical PNC- method application while processing tooth carious cavities are presented in order to estimate efficiency of the mechanical and antiseptic processing of teeth. It is revealed that the PNC-method can be used as for differential diagnostics of a degree dental carious stage, as for estimating of carefulness of tooth cavity processing before filling.

New method to study bacterial adhesion to meat.

PubMed Central

Piette, J P; Idziak, E S

1989-01-01

A new method was developed for the study of bacterial adhesion to meat surfaces. Thin slices of meat (40 microns thick) were inserted into a specially designed observation chamber. The meat slices were then exposed to a bacterial suspension (ca. 10(6) CFU.ml-1) to initiate adhesion (20 min of contact time) and subsequently rinsed to eliminate nonadherent bacteria. Because of the special chamber design, the disruptive force exerted on the bacteria during rinsing (shear stress) was uniform over the whole surface of the meat slices, was constant, and could be varied from 0 to 0.08 N.m-2. After being rinsed, the meat slices were stained with basic fuschin and observed under light microscopy to determine the number and distribution of adherent bacteria. This new method was used to study the adhesion of Acinetobacter strain LD2, a Lactobacillus sp., and Pseudomonas fluorescens to slices of beef fat and tendon. At 25 degrees C, most (greater than or equal to 99.9%) of the cells of the Lactobacillus sp. deposited on the meat were washed off the surface during rinsing (0.05 N.m-2), whereas a large number (ca. 10(5) CFU.cm-2) of Acinetobacter strain LD2 and P. fluorescens cells remained adherent. The extent of adhesion was similar on fat and tendon, and adherent bacteria were distributed evenly over the whole surface of the slices. This preliminary study indicates that the combined use of thin slices of meat and of the observation chamber provides us with the means to more accurately study bacterial adhesion to meat surfaces. Images PMID:2764565

Ripple artifact reduction using slice overlap in slice encoding for metal artifact correction.

PubMed

den Harder, J Chiel; van Yperen, Gert H; Blume, Ulrike A; Bos, Clemens

2015-01-01

Multispectral imaging (MSI) significantly reduces metal artifacts. Yet, especially in techniques that use gradient selection, such as slice encoding for metal artifact correction (SEMAC), a residual ripple artifact may be prominent. Here, an analysis is presented of the ripple artifact and of slice overlap as an approach to reduce the artifact. The ripple artifact was analyzed theoretically to clarify its cause. Slice overlap, conceptually similar to spectral bin overlap in multi-acquisition with variable resonances image combination (MAVRIC), was achieved by reducing the selection gradient and, thus, increasing the slice profile width. Time domain simulations and phantom experiments were performed to validate the analyses and proposed solution. Discontinuities between slices are aggravated by signal displacement in the frequency encoding direction in areas with deviating B0. Specifically, it was demonstrated that ripple artifacts appear only where B0 varies both in-plane and through-plane. Simulations and phantom studies of metal implants confirmed the efficacy of slice overlap to reduce the artifact. The ripple artifact is an important limitation of gradient selection based MSI techniques, and can be understood using the presented simulations. At a scan-time penalty, slice overlap effectively addressed the artifact, thereby improving image quality near metal implants. © 2014 Wiley Periodicals, Inc.

Incorporation of carbohydrate residues into peroxidase isoenzymes in horseradish roots.

PubMed

Lew, J Y; Shannon, L M

1973-11-01

Sliced root tissue of the horseradish plant (Armoracia rusticana), when incubated with mannose-U-(14)C, incorporated radioactivity into peroxidase isoenzymes. Over 90% of the radioactivity in the highly purified peroxidase isoenzymes was present in the neutral sugar residues of the molecule, i.e. fucose, arabinose, xylose, mannose. When the root slices were incubated simultaneously with leucine-4,5-(3)H and mannose-U-(14)C, cycloheximide strongly inhibited leucine incorporation into the peptide portion of peroxidase isoenzymes but had little effect on the incorporation of (14)C into the neutral sugars. These results indicated that synthesis of the peptide portion of peroxidase was completed before the monosaccharide residues were attached to the molecule. This temporal relationship between the synthesis of protein and the attachment of carbohydrate residues in the plant glycoprotein, horseradish peroxidase, appears to be similar to that reported for glycoprotein biosynthesis in many mammalian systems.

Incorporation of Carbohydrate Residues into Peroxidase Isoenzymes in Horseradish Roots

PubMed Central

Lew, Jow Y.; Shannon, Leland M.

1973-01-01

Sliced root tissue of the horseradish plant (Armoracia rusticana), when incubated with mannose-U-14C, incorporated radioactivity into peroxidase isoenzymes. Over 90% of the radioactivity in the highly purified peroxidase isoenzymes was present in the neutral sugar residues of the molecule, i.e. fucose, arabinose, xylose, mannose. When the root slices were incubated simultaneously with leucine-4,5-3H and mannose-U-14C, cycloheximide strongly inhibited leucine incorporation into the peptide portion of peroxidase isoenzymes but had little effect on the incorporation of 14C into the neutral sugars. These results indicated that synthesis of the peptide portion of peroxidase was completed before the monosaccharide residues were attached to the molecule. This temporal relationship between the synthesis of protein and the attachment of carbohydrate residues in the plant glycoprotein, horseradish peroxidase, appears to be similar to that reported for glycoprotein biosynthesis in many mammalian systems. PMID:16658584

Nanowires precisely grown on the ends of microwire electrodes permit the recording of intracellular action potentials within deeper neural structures

PubMed Central

Ferguson, John E; Boldt, Christopher; Puhl, Joshua G; Stigen, Tyler W; Jackson, Jadin C; Crisp, Kevin M; Mesce, Karen A; Netoff, Theoden I; Redish, A David

2012-01-01

Aims Nanoelectrodes are an emerging biomedical technology that can be used to record intracellular membrane potentials from neurons while causing minimal damage during membrane penetration. Current nanoelectrode designs, however, have low aspect ratios or large substrates and thus are not suitable for recording from neurons deep within complex natural structures, such as brain slices. Materials & methods We describe a novel nanoelectrode design that uses nanowires grown on the ends of microwire recording electrodes similar to those frequently used in vivo. Results & discussion We demonstrate that these nanowires can record intracellular action potentials in a rat brain slice preparation and in isolated leech ganglia. Conclusion Nanoelectrodes have the potential to revolutionize intracellular recording methods in complex neural tissues, to enable new multielectrode array technologies and, ultimately, to be used to record intracellular signals in vivo. PMID:22475650

Semiautomatic tumor segmentation with multimodal images in a conditional random field framework.

PubMed

Hu, Yu-Chi; Grossberg, Michael; Mageras, Gikas

2016-04-01

Volumetric medical images of a single subject can be acquired using different imaging modalities, such as computed tomography, magnetic resonance imaging (MRI), and positron emission tomography. In this work, we present a semiautomatic segmentation algorithm that can leverage the synergies between different image modalities while integrating interactive human guidance. The algorithm provides a statistical segmentation framework partly automating the segmentation task while still maintaining critical human oversight. The statistical models presented are trained interactively using simple brush strokes to indicate tumor and nontumor tissues and using intermediate results within a patient's image study. To accomplish the segmentation, we construct the energy function in the conditional random field (CRF) framework. For each slice, the energy function is set using the estimated probabilities from both user brush stroke data and prior approved segmented slices within a patient study. The progressive segmentation is obtained using a graph-cut-based minimization. Although no similar semiautomated algorithm is currently available, we evaluated our method with an MRI data set from Medical Image Computing and Computer Assisted Intervention Society multimodal brain segmentation challenge (BRATS 2012 and 2013) against a similar fully automatic method based on CRF and a semiautomatic method based on grow-cut, and our method shows superior performance.

Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices.

PubMed

Vega-Gálvez, Antonio; Ah-Hen, Kong; Chacana, Marcelo; Vergara, Judith; Martínez-Monzó, Javier; García-Segovia, Purificación; Lemus-Mondaca, Roberto; Di Scala, Karina

2012-05-01

The aim of this work was to study the effect of temperature and air velocity on the drying kinetics and quality attributes of apple (var. Granny Smith) slices during drying. Experiments were conducted at 40, 60 and 80°C, as well as at air velocities of 0.5, 1.0 and 1.5ms(-1). Effective moisture diffusivity increased with temperature and air velocity, reaching a value of 15.30×10(-9)m(2)s(-1) at maximum temperature and air velocity under study. The rehydration ratio changed with varying both air velocity and temperature indicating tissue damage due to processing. The colour difference, ΔE, showed the best results at 80°C. The DPPH-radical scavenging activity at 40°C and 0.5ms(-1) showed the highest antioxidant activity, closest to that of the fresh sample. Although ΔE decreased with temperature, antioxidant activity barely varied and even increased at high air velocities, revealing an antioxidant capacity of the browning products. The total phenolics decreased with temperature, but at high air velocity retardation of thermal degradation was observed. Firmness was also determined and explained using glass transition concept and microstructure analysis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Is it a biological response or chemical process? Chemical and transcriptional regulation experiments probe the cause for the increased accumulation of chlorogenic acid (CGA) in carrot root slices exposed to UV-B light

USDA-ARS?s Scientific Manuscript database

We recently demonstrated that wounded carrot roots subjected to a brief UV-B light treatment accumulate large quantities of chlorogenic acid (CGA) in the treated tissues. Chlorogenic acid is an intermediate in the phenylpropanoid pathway and a potent anti-oxidant. Chemical analysis and real-time P...

Changes in the contractile state, fine structure and metabolism of cardiac muscle cells during the development of rigor mortis.

PubMed

Vanderwee, M A; Humphrey, S M; Gavin, J B; Armiger, L C

1981-01-01

Transmural slices from the left anterior papillary muscle of dog hearts were maintained for 120 min in a moist atmosphere at 37 degrees C. At 15-min intervals tissue samples were taken for estimation of adenosine triphosphate (ATP) and glucose-6-phosphate (G6P) and for electron microscopic examination. At the same time the deformability under standard load of comparable regions of an adjacent slice of tissue was measured. ATP levels fell rapidly during the first 45 to 75 min after excision of the heart. During a subsequent further decline in ATP, the mean deformability of myocardium fell from 30 to 12% indicating the development of rigor mortis. Conversely, G6P levels increased during the first decline in adenosine triphosphate but remained relatively steady thereafter. Whereas many of the myocardial cells fixed after 5 min contracted on contact with glutaraldehyde, all cells examined after 15 to 40 min were relaxed. A progressive increase in the proportion of contracted cells was observed during the rapid increase in myocardial rigidity. During this late contraction the cells showed morphological evidence of irreversible injury. These findings suggest that ischaemic myocytes contract just before actin and myosin become strongly linked to maintain the state of rigor mortis.

Optical coherence tomography visualizes neurons in human entorhinal cortex

PubMed Central

Magnain, Caroline; Augustinack, Jean C.; Konukoglu, Ender; Frosch, Matthew P.; Sakadžić, Sava; Varjabedian, Ani; Garcia, Nathalie; Wedeen, Van J.; Boas, David A.; Fischl, Bruce

2015-01-01

Abstract. The cytoarchitecture of the human brain is of great interest in diverse fields: neuroanatomy, neurology, neuroscience, and neuropathology. Traditional histology is a method that has been historically used to assess cell and fiber content in the ex vivo human brain. However, this technique suffers from significant distortions. We used a previously demonstrated optical coherence microscopy technique to image individual neurons in several square millimeters of en-face tissue blocks from layer II of the human entorhinal cortex, over 50  μm in depth. The same slices were then sectioned and stained for Nissl substance. We registered the optical coherence tomography (OCT) images with the corresponding Nissl stained slices using a nonlinear transformation. The neurons were then segmented in both images and we quantified the overlap. We show that OCT images contain information about neurons that is comparable to what can be obtained from Nissl staining, and thus can be used to assess the cytoarchitecture of the ex vivo human brain with minimal distortion. With the future integration of a vibratome into the OCT imaging rig, this technique can be scaled up to obtain undistorted volumetric data of centimeter cube tissue blocks in the near term, and entire human hemispheres in the future. PMID:25741528

Bioorthogonal chemical imaging of metabolic activities in live mammalian hippocampal tissues with stimulated Raman scattering

NASA Astrophysics Data System (ADS)

Hu, Fanghao; Lamprecht, Michael R.; Wei, Lu; Morrison, Barclay; Min, Wei

2016-12-01

Brain is an immensely complex system displaying dynamic and heterogeneous metabolic activities. Visualizing cellular metabolism of nucleic acids, proteins, and lipids in brain with chemical specificity has been a long-standing challenge. Recent development in metabolic labeling of small biomolecules allows the study of these metabolisms at the global level. However, these techniques generally require nonphysiological sample preparation for either destructive mass spectrometry imaging or secondary labeling with relatively bulky fluorescent labels. In this study, we have demonstrated bioorthogonal chemical imaging of DNA, RNA, protein and lipid metabolism in live rat brain hippocampal tissues by coupling stimulated Raman scattering microscopy with integrated deuterium and alkyne labeling. Heterogeneous metabolic incorporations for different molecular species and neurogenesis with newly-incorporated DNA were observed in the dentate gyrus of hippocampus at the single cell level. We further applied this platform to study metabolic responses to traumatic brain injury in hippocampal slice cultures, and observed marked upregulation of protein and lipid metabolism particularly in the hilus region of the hippocampus within days of mechanical injury. Thus, our method paves the way for the study of complex metabolic profiles in live brain tissue under both physiological and pathological conditions with single-cell resolution and minimal perturbation.

Developmental imaging: the avian embryo hatches to the challenge.

PubMed

Kulesa, Paul M; McKinney, Mary C; McLennan, Rebecca

2013-06-01

The avian embryo provides a multifaceted model to study developmental mechanisms because of its accessibility to microsurgery, fluorescence cell labeling, in vivo imaging, and molecular manipulation. Early two-dimensional planar growth of the avian embryo mimics human development and provides unique access to complex cell migration patterns using light microscopy. Later developmental events continue to permit access to both light and other imaging modalities, making the avian embryo an excellent model for developmental imaging. For example, significant insights into cell and tissue behaviors within the primitive streak, craniofacial region, and cardiovascular and peripheral nervous systems have come from avian embryo studies. In this review, we provide an update to recent advances in embryo and tissue slice culture and imaging, fluorescence cell labeling, and gene profiling. We focus on how technical advances in the chick and quail provide a clearer understanding of how embryonic cell dynamics are beautifully choreographed in space and time to sculpt cells into functioning structures. We summarize how these technical advances help us to better understand basic developmental mechanisms that may lead to clinical research into human birth defects and tissue repair. Copyright © 2013 Wiley Periodicals, Inc.

Comparison of 68Ga-HBED-CC PSMA-PET/CT and multiparametric MRI for gross tumour volume detection in patients with primary prostate cancer based on slice by slice comparison with histopathology

PubMed Central

Zamboglou, Constantinos; Drendel, Vanessa; Jilg, Cordula A.; Rischke, Hans C.; Beck, Teresa I.; Schultze-Seemann, Wolfgang; Krauss, Tobias; Mix, Michael; Schiller, Florian; Wetterauer, Ulrich; Werner, Martin; Langer, Mathias; Bock, Michael; Meyer, Philipp T.; Grosu, Anca L.

2017-01-01

Purpose: The exact detection and delineation of the intraprostatic tumour burden is crucial for treatment planning in primary prostate cancer (PCa). We compared 68Ga-HBED-CC-PSMA PET/CT with multiparametric MRI (mpMRI) for diagnosis and tumour delineation in patients with primary PCa based on slice by slice correlation with histopathological reference material. Methodology: Seven patients with histopathologically proven primary PCa underwent 68Ga-HBED-CC-PSMA PET/CT and MRI followed by radical prostatectomy. Resected prostates were scanned by ex-vivo CT in a special localizer and prepared for histopathology. Invasive PCa was delineated on a HE stained histologic tissue slide and matched to ex-vivo CT to obtain gross tumor volume (GTV-)histo. Ex-vivo CT including GTV-histo and MRI data were matched to in-vivo CT(PET). Consensus contours based on MRI (GTV-MRI), PSMA PET (GTV-PET) or the combination of both (GTV-union/-intersection) were created. In each in-vivo CT slice the prostate was separated into 4 equal segments and sensitivity and specificity for PSMA PET and mpMRI were assessed by comparison with histological reference material. Furthermore, the spatial overlap between GTV-histo and GTV-PET/-MRI and the Sørensen-Dice coefficient (DSC) were calculated. In the case of multifocal PCa (4/7 patients), SUV values (PSMA PET) and ADC-values (diffusion weighted MRI) were obtained for each lesion. Results: PSMA PET and mpMRI detected PCa in all patients. GTV-histo was detected in 225 of 340 segments (66.2%). Sensitivity and specificity for GTV-PET, GTV-MRI, GTV-union and GTV-intersection were 75% and 87%, 70% and 82%, 82% and 67%, 55% and 99%, respectively. GTV-histo had on average the highest overlap with GTV-union (57±22%), which was significantly higher than overlap with GTV-MRI (p=0.016) and GTV-PET (p=0.016), respectively. The mean DSC for GTV-union, GTV-PET and GTV-MRI was 0.51 (±0.18), 0.45 (±0.17) and 0.48 (±0.19), respectively. In every patient with multifocal PCa there was one lesion which had both the highest SUV and the lowest ADC-value (mean and max). Conclusion: In a slice by slice analysis with histopathology, 68Ga-HBED-CC-PSMA PET/CT and mpMRI showed high sensitivity and specificity in detection of primary PCa. A combination of both methods performed even better in terms of sensitivity (GTV-union) and specificity (GTV-intersection). A moderate to good spatial overlap with GTV-histo was observed for PSMA PET/CT and mpMRI alone which was significantly improved by GTV-union. Further studies are warranted to analyse the impact of these preliminary findings for diagnostic (multimodal guided TRUS biopsy) and therapeutic (focal therapy) strategies in primary PCa. PMID:28042330

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

Johnston, H; UT Southwestern Medical Center, Dallas, TX; Hilts, M

Purpose: To commission a multislice computed tomography (CT) scanner for fast and reliable readout of radiation therapy (RT) dose distributions using CT polymer gel dosimetry (PGD). Methods: Commissioning was performed for a 16-slice CT scanner using images acquired through a 1L cylinder filled with water. Additional images were collected using a single slice machine for comparison purposes. The variability in CT number associated with the anode heel effect was evaluated and used to define a new slice-by-slice background image subtraction technique. Image quality was assessed for the multislice system by comparing image noise and uniformity to that of the singlemore » slice machine. The consistency in CT number across slices acquired simultaneously using the multislice detector array was also evaluated. Finally, the variability in CT number due to increasing x-ray tube load was measured for the multislice scanner and compared to the tube load effects observed on the single slice machine. Results: Slice-by-slice background subtraction effectively removes the variability in CT number across images acquired simultaneously using the multislice scanner and is the recommended background subtraction method when using a multislice CT system. Image quality for the multislice machine was found to be comparable to that of the single slice scanner. Further study showed CT number was consistent across image slices acquired simultaneously using the multislice detector array for each detector configuration of the slice thickness examined. In addition, the multislice system was found to eliminate variations in CT number due to increasing x-ray tube load and reduce scanning time by a factor of 4 when compared to imaging a large volume using a single slice scanner. Conclusion: A multislice CT scanner has been commissioning for CT PGD, allowing images of an entire dose distribution to be acquired in a matter of minutes. Funding support provided by the Natural Sciences and Engineering Research Council of Canada (NSERC)« less

Integration of technologies for hepatic tissue engineering.

PubMed

Nahmias, Yaakov; Berthiaume, Francois; Yarmush, Martin L

2007-01-01

The liver is the largest internal organ in the body, responsible for over 500 metabolic, regulatory, and immune functions. Loss of liver function leads to liver failure which causes over 25,000 deaths/year in the United States. Efforts in the field of hepatic tissue engineering include the design of bioartificial liver systems to prolong patient's lives during liver failure, for drug toxicity screening and for the study of liver regeneration, ischemia/reperfusion injury, fibrosis, viral infection, and inflammation. This chapter will overview the current state-of-the-art in hepatology including isolated perfused liver, culture of liver slices and tissue explants, hepatocyte culture on collagen "sandwich" and spheroids, coculture of hepatocytes with non-parenchymal cells, and the integration of these culture techniques with microfluidics and reactor design. This work will discuss the role of oxygen and medium composition in hepatocyte culture and present promising new technologies for hepatocyte proliferation and function. We will also discuss liver development, architecture, and function as they relate to these culture techniques. Finally, we will review current opportunities and major challenges in integrating cell culture, bioreactor design, and microtechnology to develop new systems for novel applications.

Automatic segementation of histological structures in normal and neoplastic mammary gland tissue sections

NASA Astrophysics Data System (ADS)

Fernandez-Gonzalez, Rodrigo; Deschamps, Thomas; Idica, Adam; Malladi, Ravikanth; Ortiz de Solorzano, Carlos

2003-07-01

In this paper we present a scheme for real time segmentation of histological structures in microscopic images of normal and neoplastic mammary gland sections. Paraffin embedded or frozen tissue blocks are sliced, and sections are stained with hematoxylin and eosin (H&E). The sections are then imaged using conventional bright field microscopy. The background of the images is corrected by arithmetic manipulation using a "phantom." Then we use the fast marching method with a speed function that depends on the brightness gradient of the image to obtain a preliminary approximation to the boundaries of the structures of interest within a region of interest (ROI) of the entire section manually selected by the user. We use the result of the fast marching method as the initial condition for the level set motion equation. We run this last method for a few steps and obtain the final result of the segmentation. These results can be connected from section to section to build a three-dimensional reconstruction of the entire tissue block that we are studying.

Venlafaxine inhibits apoptosis of hippocampal neurons by up-regulating brain-derived neurotrophic factor in a rat depression model

PubMed Central

Huang, Xiao; Mao, Yue-Shi; Li, Chao; Wang, Hao; Ji, Jian-Lin

2014-01-01

Objective: To study the effect of venlafaxine on the expression of brain-derived neurotrophic factor (BDNF) in rat hippocampal neurons, as well as its inhibitory effect on apoptosis of hippocampal neurons. Methods: Differences in behavioral ability between the depression model group and the Venlafaxine treatment group were observed using behavioral, sucrose-water and open field tests. The rat hippocampal tissue was sliced, stained and observed for BDNF distribution by immunohistochemistry. Apoptosis of hippocampal neurons was detected by TUNEL. BDNF expression in the hippocampal tissue was detected by Western blot. Injury and apoptosis of the hippocampal tissue were observed by electron microscopy. Results: Behavioral test showed that venlafaxine effectively improved the behavioral abilities of depressed rats. Immunohistochemistry showed that venlafaxine markedly increased the BDNF expression in the rat hippocampus. TUNEL showed that venlafaxine markedly inhibited apoptosis of hippocampal neurons, which was also confirmed by electron microscopic observation of the pathologic sections. Conclusion: Venlafaxine improved the expression of BDNF through working on PI3k/PKB/eNOS pathway and repressed the apoptosis of hippocampal neurons. PMID:25197330

SU-F-T-414: Mathematical Formulation of Gantry Starting Angle for Right Medial Tangential Arc in Left Intact Partial Breast Irradiation Using Volumetric Modulated Arc Therapy (VMAT)

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

Giri, U; Sarkar, B; Kaur, H

Purpose: To choose appropriate gantry starting angle for partial left breast irradiation using volumetric modulated arc therapy (VMAT). Methods: A random patient of left breast carcinoma was selected for this study. The slice which was selected for this mathematical formulation was having maximum breast thickness and maximum medial and lateral tangential distance. After this appropriate isocenter was chosen on that CT slice. The distances between various points were measured by the measuring tool in Monaco 5.00.04. Using the various trigonometric equations, a final equation was derived which shows the relationship between Gantry start angle, isocenter Location and tissue thickness. Results:more » The final equation for gantry start for right medial tangential arc is given asStarting angle = 270°+tan^(−1)(sin(θ)/(x-1/x-2 +cosθ))The above equation was tested for 10 cases and it was found to be appropriate for all the cases. Conclusion: Gantry starting angle for partial arc irradiation depends upon Breast thickness, Distance between Medial and lateral tangent and isocenter location.« less

Slice simulation from a model of the parenchymous vascularization to evaluate texture features: work in progress.

PubMed

Rolland, Y; Bézy-Wendling, J; Duvauferrier, R; Coatrieux, J L

1999-03-01

To demonstrate the usefulness of a model of the parenchymous vascularization to evaluate texture analysis methods. Slices with thickness varying from 1 to 4 mm were reformatted from a 3D vascular model corresponding to either normal tissue perfusion or local hypervascularization. Parameters of statistical methods were measured on 16128x128 regions of interest, and mean values and standard deviation were calculated. For each parameter, the performances (discrimination power and stability) were evaluated. Among 11 calculated statistical parameters, three (homogeneity, entropy, mean of gradients) were found to have a good discriminating power to differentiate normal perfusion from hypervascularization, but only the gradient mean was found to have a good stability with respect to the thickness. Five parameters (run percentage, run length distribution, long run emphasis, contrast, and gray level distribution) were found to have intermediate results. In the remaining three, curtosis and correlation was found to have little discrimination power, skewness none. This 3D vascular model, which allows the generation of various examples of vascular textures, is a powerful tool to assess the performance of texture analysis methods. This improves our knowledge of the methods and should contribute to their a priori choice when designing clinical studies.

Deep tissue optical focusing and optogenetic modulation with time-reversed ultrasonically encoded light

PubMed Central

Ruan, Haowen; Brake, Joshua; Robinson, J. Elliott; Liu, Yan; Jang, Mooseok; Xiao, Cheng; Zhou, Chunyi; Gradinaru, Viviana; Yang, Changhuei

2017-01-01

Noninvasive light focusing deep inside living biological tissue has long been a goal in biomedical optics. However, the optical scattering of biological tissue prevents conventional optical systems from tightly focusing visible light beyond several hundred micrometers. The recently developed wavefront shaping technique time-reversed ultrasonically encoded (TRUE) focusing enables noninvasive light delivery to targeted locations beyond the optical diffusion limit. However, until now, TRUE focusing has only been demonstrated inside nonliving tissue samples. We present the first example of TRUE focusing in 2-mm-thick living brain tissue and demonstrate its application for optogenetic modulation of neural activity in 800-μm-thick acute mouse brain slices at a wavelength of 532 nm. We found that TRUE focusing enabled precise control of neuron firing and increased the spatial resolution of neuronal excitation fourfold when compared to conventional lens focusing. This work is an important step in the application of TRUE focusing for practical biomedical uses. PMID:29226248

[Evaluation of the resolving power of different angles in MPR images of 16DAS-MDCT].

PubMed

Kimura, Mikio; Usui, Junshi; Nozawa, Takeo

2007-03-20

In this study, we evaluated the resolving power of three-dimensional (3D) multiplanar reformation (MPR) images with various angles by using 16 data acquisition system multi detector row computed tomography (16DAS-MDCT) . We reconstructed the MPR images using data with a 0.75 mm slice thickness of the axial image in this examination. To evaluate resolving power, we used an original new phantom (RC phantom) that can be positioned at any slice angle in MPR images. We measured the modulation transfer function (MTF) by using the methods of measuring pre-sampling MTF, and used Fourier transform of image data of the square wave chart. The scan condition and image reconstruction condition that were adopted in this study correspond to the condition that we use for three-dimensional computed tomographic angiography (3D-CTA) examination of the head in our hospital. The MTF of MPR images showed minimum values at slice angles in parallel with the axial slice, and showed maximum values at the sagittal slice and coronal slice angles that are parallel to the Z-axis. With an oblique MPR image, MTF did not change with angle changes in the oblique sagittal slice plane, but in the oblique coronal slice plane, MTF increased as the tilt angle increased from the axial plane to the Z plane. As a result, we could evaluate the resolving power of a head 3D image by measuring the MTF of the axial image and sagittal image or the coronal image.

Morphological spot counting from stacked images for automated analysis of gene copy numbers by fluorescence in situ hybridization.

PubMed

Grigoryan, Artyom M; Dougherty, Edward R; Kononen, Juha; Bubendorf, Lukas; Hostetter, Galen; Kallioniemi, Olli

2002-01-01

Fluorescence in situ hybridization (FISH) is a molecular diagnostic technique in which a fluorescent labeled probe hybridizes to a target nucleotide sequence of deoxyribose nucleic acid. Upon excitation, each chromosome containing the target sequence produces a fluorescent signal (spot). Because fluorescent spot counting is tedious and often subjective, automated digital algorithms to count spots are desirable. New technology provides a stack of images on multiple focal planes throughout a tissue sample. Multiple-focal-plane imaging helps overcome the biases and imprecision inherent in single-focal-plane methods. This paper proposes an algorithm for global spot counting in stacked three-dimensional slice FISH images without the necessity of nuclei segmentation. It is designed to work in complex backgrounds, when there are agglomerated nuclei, and in the presence of illumination gradients. It is based on the morphological top-hat transform, which locates intensity spikes on irregular backgrounds. After finding signals in the slice images, the algorithm groups these together to form three-dimensional spots. Filters are employed to separate legitimate spots from fluorescent noise. The algorithm is set in a comprehensive toolbox that provides visualization and analytic facilities. It includes simulation software that allows examination of algorithm performance for various image and algorithm parameter settings, including signal size, signal density, and the number of slices.

A flexible and accurate digital volume correlation method applicable to high-resolution volumetric images

NASA Astrophysics Data System (ADS)

Pan, Bing; Wang, Bo

2017-10-01

Digital volume correlation (DVC) is a powerful technique for quantifying interior deformation within solid opaque materials and biological tissues. In the last two decades, great efforts have been made to improve the accuracy and efficiency of the DVC algorithm. However, there is still a lack of a flexible, robust and accurate version that can be efficiently implemented in personal computers with limited RAM. This paper proposes an advanced DVC method that can realize accurate full-field internal deformation measurement applicable to high-resolution volume images with up to billions of voxels. Specifically, a novel layer-wise reliability-guided displacement tracking strategy combined with dynamic data management is presented to guide the DVC computation from slice to slice. The displacements at specified calculation points in each layer are computed using the advanced 3D inverse-compositional Gauss-Newton algorithm with the complete initial guess of the deformation vector accurately predicted from the computed calculation points. Since only limited slices of interest in the reference and deformed volume images rather than the whole volume images are required, the DVC calculation can thus be efficiently implemented on personal computers. The flexibility, accuracy and efficiency of the presented DVC approach are demonstrated by analyzing computer-simulated and experimentally obtained high-resolution volume images.

Effects of endogenous pyrogen and prostaglandin E2 on hypothalamic neurons in rat brain slices.

PubMed

Watanabe, T; Morimoto, A; Murakami, N

1987-06-01

We investigated the effects of endogenous pyrogen and prostaglandin E2 (PGE2) on the preoptic and anterior hypothalamic (POAH) neurons using brain slice preparations from the rat. Partially purified endogenous pyrogen did not change the activities of most of the neurons in the POAH region when applied locally through a micropipette attached to the recording electrode in proximity to the neurons. This indicates that partially purified endogenous pyrogen does not act directly on the neuronal activity in the POAH region. The partially purified endogenous pyrogen, applied into a culture chamber containing a brain slice, facilitated the activities in 24% of the total neurons tested, regardless of the thermal specificity of the neurons. Moreover, PGE2 added to the culture chamber facilitated 48% of the warm-responsive, 33% of the cold-responsive, and 29% of the thermally insensitive neurons. The direction of change in neuronal activity induced by partially purified endogenous pyrogen appears to be almost the same as that induced by PGE2 when these substances were applied by perfusion to the same neuron in the culture chamber. These results suggest that partially purified pyrogen applied to the perfusate of the culture chamber stimulates some constituents of brain tissue to synthesize and release prostaglandin, which in turn affects the neuronal activity of the POAH region.

Organ dose measurements from multiple-detector computed tomography using a commercial dosimetry system and tomographic, physical phantoms

NASA Astrophysics Data System (ADS)

Lavoie, Lindsey K.

The technology of computed tomography (CT) imaging has soared over the last decade with the use of multi-detector CT (MDCT) scanners that are capable of performing studies in a matter of seconds. While the diagnostic information obtained from MDCT imaging is extremely valuable, it is important to ensure that the radiation doses resulting from these studies are at acceptably safe levels. This research project focused on the measurement of organ doses resulting from modern MDCT scanners. A commercially-available dosimetry system was used to measure organ doses. Small dosimeters made of optically-stimulated luminescent (OSL) material were analyzed with a portable OSL reader. Detailed verification of this system was performed. Characteristics studied include energy, scatter, and angular responses; dose linearity, ability to erase the exposed dose and ability to reuse dosimeters multiple times. The results of this verification process were positive. While small correction factors needed to be applied to the dose reported by the OSL reader, these factors were small and expected. Physical, tomographic pediatric and adult phantoms were used to measure organ doses. These phantoms were developed from CT images and are composed of tissue-equivalent materials. Because the adult phantom is comprised of numerous segments, dosimeters were placed in the phantom at several organ locations, and doses to select organs were measured using three clinical protocols: pediatric craniosynostosis, adult brain perfusion and adult cardiac CT angiography (CTA). A wide-beam, 320-slice, volumetric CT scanner and a 64-slice, MDCT scanner were used for organ dose measurements. Doses ranged from 1 to 26 mGy for the pediatric protocol, 1 to 1241 mGy for the brain perfusion protocol, and 2-100 mGy for the cardiac protocol. In most cases, the doses measured on the 64-slice scanner were higher than those on the 320-slice scanner. A methodology to measure organ doses with OSL dosimeters received from CT imaging has been presented. These measurements are especially important in keeping with the ALARA (as low as reasonably achievable) principle. While diagnostic information from CT imaging is valuable and necessary, the dose to patients is always a consideration. This methodology aids in this important task. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Sensitivity to detect small coronary artery calcium lesions with varying slice thickness using electron beam tomography.

PubMed

Mao, Songshou; Child, Janis; Carson, Sivi; Liu, Steve C K; Oudiz, Ronald J; Budoff, Matthew J

2003-03-01

To estimate the sensitivity to find small coronary artery calcium lesions with use of different slice widths with electron beam tomography. Two studies were performed. Study 1 utilized double scanning of a stationary cork phantom with three different slice thickness (1.5, 3, and 6 mm). Fifty different calcific lesions (all <20 mm2 in area) fitted in 10 cork coronary arteries were utilized. The calcium foci area, peak value and score were measured and compared. In group 2, 30 patients underwent coronary artery calcium (CAC) screen studies. Each patient was scanned with both 3-mm and 6-mm scan widths in a same study time. Lesions with < 20 mm2 of area of CAC were measured on both 3-mm and 6-mm images. The mean and peak Hounsfield unit measure, and Agatston score were compared between both images. In the cork study, the sensitivity to detect small calcium foci were 96% (48/50), 82% (41/50), and 34% (17/50) in images with 1.5-, 3-, and 6-mm slice thickness, respectively. There is a smaller value in mass, and calcium volume in 6-mm images than 1.5-mm and 3-mm images ( P< 0.001). There was no significant difference between the true value and measured value from 1.5-mm and 3-mm images. In the human study, 18 (30%) of 60 CAC lesions with an area < 20 mm2 defined on 3 mm images were not visible on 6-mm images. Sensitivity of small lesions (P< 5 mm2) was 48% using 6-mm slices. There was a smaller value in CAC area, mean and peak Hounsfield units and score measured from 6-mm images, as compared with 3 mm slices ( P< 0.05). Thinner slice imaging has a higher sensitivity to detect small calcium focus. There was no significant change in score between 3 mm and 1.5 mm on the cork phantom study. However, the use of 6-mm slices should be discouraged, as this protocol both underestimates calcific mass and misses a significant number of calcific lesions in both a phantom and human study.

Stabilization of a finite slice in miscible displacement in homogeneous porous media

NASA Astrophysics Data System (ADS)

Pramanik, Satyajit; Mishra, Manoranjan

2016-11-01

We numerically studied the miscible displacement of a finite slice of variable viscosity and density. The stability of the finite slice depends on different flow parameters, such as displacement velocity U, mobility ratio R , and the density contrast. Series of numerical simulations corresponding to different ordered pair (R, U) in the parameter space, and a given density contrast reveal six different instability regions. We have shown that independent of the width of the slice, there always exists a region of stable displacement, and below a critical value of the slice width, this stable region increases with decreasing slice width. Further we observe that the viscous fingering (buoyancy-induced instability) at the upper interface induces buoyancy-induced instability (viscous fingering) at the lower interface. Besides the fundamental fluid dynamics understanding, our results can be helpful to model CO2 sequestration and chromatographic separation.

Simple Estimation of the Endolymphatic Volume Ratio after Intravenous Administration of a Single-dose of Gadolinium Contrast

PubMed Central

NAGANAWA, Shinji; KANOU, Mai; OHASHI, Toshio; KUNO, Kayao; SONE, Michihiko

2016-01-01

Purpose: To evaluate the feasibility of a simple estimation for the endolymphatic volume ratio (endolymph volume/total lymph volume = %ELvolume) from an area ratio obtained from only one slice (%EL1slice) or from three slices (%EL3slices). The %ELvolume, calculated from a time-consuming measurement on all magnetic resonance (MR) slices, was compared to the %EL1slice and the %EL3slices. Methods: In 40 ears of 20 patients with a clinical suspicion of endolymphatic hydrops, MR imaging was performed 4 hours after intravenous administration of a single dose of gadolinium-based contrast material (IV-SD-GBCM). Using previously reported HYDROPS2-Mi2 MR imaging, the %ELvolume values in the cochlea and the vestibule were measured separately by two observers. The correlations between the %EL1slice or the %EL3slices and the %ELvolume values were evaluated. Results: A strong linear correlation was observed between the %ELvolume and the %EL3slices or the %EL1slice in the cochlea. The Pearson correlation coefficient (r) was 0.968 (3 slices) and 0.965 (1 slice) for observer A, and 0.968 (3 slices) and 0.964 (1 slice) for observer B (P < 0.001, for all). A strong linear correlation was also observed between the %ELvolume and the %EL3slices or the %EL1slice in the vestibule. The Pearson correlation coefficient (r) was 0.980 (3 slices) and 0.953 (1 slice) for observer A, and 0.979 (3 slices) and 0.952 (1 slice) for observer B (P < 0.001, for all). The high intra-class correlation coefficients (0.991–0.997) between the endolymph volume ratios by two observers were observed in both the cochlea and the vestibule for values of the %ELvolume, the %EL3slices and the %EL1slice. Conclusion: The %ELvolume might be easily estimated from the %EL3slices or the %EL1slice. PMID:27001396

Simple Estimation of the Endolymphatic Volume Ratio after Intravenous Administration of a Single-dose of Gadolinium Contrast.

PubMed

Naganawa, Shinji; Kanou, Mai; Ohashi, Toshio; Kuno, Kayao; Sone, Michihiko

2016-10-11

To evaluate the feasibility of a simple estimation for the endolymphatic volume ratio (endolymph volume/total lymph volume = %EL volume ) from an area ratio obtained from only one slice (%EL 1slice ) or from three slices (%EL 3slices ). The %EL volume, calculated from a time-consuming measurement on all magnetic resonance (MR) slices, was compared to the %EL 1slice and the %EL 3slices . In 40 ears of 20 patients with a clinical suspicion of endolymphatic hydrops, MR imaging was performed 4 hours after intravenous administration of a single dose of gadolinium-based contrast material (IV-SD-GBCM). Using previously reported HYDROPS2-Mi2 MR imaging, the %EL volume values in the cochlea and the vestibule were measured separately by two observers. The correlations between the %EL 1slice or the %EL 3slices and the %EL volume values were evaluated. A strong linear correlation was observed between the %EL volume and the %EL 3slices or the %EL 1slice in the cochlea. The Pearson correlation coefficient (r) was 0.968 (3 slices) and 0.965 (1 slice) for observer A, and 0.968 (3 slices) and 0.964 (1 slice) for observer B (P < 0.001, for all). A strong linear correlation was also observed between the %EL volume and the %EL 3slices or the %EL 1slice in the vestibule. The Pearson correlation coefficient (r) was 0.980 (3 slices) and 0.953 (1 slice) for observer A, and 0.979 (3 slices) and 0.952 (1 slice) for observer B (P < 0.001, for all). The high intra-class correlation coefficients (0.991-0.997) between the endolymph volume ratios by two observers were observed in both the cochlea and the vestibule for values of the %EL volume , the %EL 3slices and the %EL 1slice . The %EL volume might be easily estimated from the %EL 3slices or the %EL 1slice .

Metal artefact reduction in MRI at both 1.5 and 3.0 T using slice encoding for metal artefact correction and view angle tilting

PubMed Central

Reichert, M; Morelli, J N; Nittka, M; Attenberger, U; Runge, V M

2015-01-01

Objective: To compare metal artefact reduction in MRI at both 3.0 T and 1.5 T using different sequence strategies. Methods: Metal implants of stainless steel screw and plate within agarose phantoms and tissue specimens as well as three patients with implants were imaged at both 1.5 T and 3.0 T, using view angle tilting (VAT), slice encoding for metal artefact correction with VAT (SEMAC-VAT) and conventional sequence. Artefact reduction in agarose phantoms was quantitatively assessed by artefact volume measurements. Blinded reads were conducted in tissue specimen and human imaging, with respect to artefact size, distortion, blurring and overall image quality. Wilcoxon and Friedman tests for multiple comparisons and intraclass correlation coefficient (ICC) for interobserver agreement were performed with a significant level of p < 0.05. Results: Compared with conventional sequences, SEMAC-VAT significantly reduced metal artefacts by 83% ± 9% for the screw and 89% ± 3% for the plate at 1.5 T; 72% ± 7% for the screw and 38% ± 13% for the plate at 3.0 T (p < 0.05). In qualitative analysis, SEMAC-VAT allowed for better visualization of tissue structures adjacent to the implants and produced better overall image quality with good interobserver agreement for both tissue specimen and human imaging (ICC = 0.80–0.99; p < 0.001). In addition, VAT also markedly reduced metal artefacts compared with conventional sequence, but was inferior to SEMAC-VAT. Conclusion: SEMAC-VAT and VAT techniques effectively reduce artefacts from metal implants relative to conventional imaging at both 1.5 T and 3.0 T. Advances in knowledge: The feasibility of metal artefact reduction with SEMAC-VAT was demonstrated at 3.0-T MR. SEMAC-VAT significantly reduced metal artefacts at both 1.5 and 3.0 T. SEMAC-VAT allowed for better visualization of the tissue structures adjacent to the metal implants. SEMAC-VAT produced consistently better image quality in both tissue specimen and human imaging. PMID:25613398

A versatile new technique to clear mouse and human brain

NASA Astrophysics Data System (ADS)

Costantini, Irene; Di Giovanna, Antonino Paolo; Allegra Mascaro, Anna Letizia; Silvestri, Ludovico; Müllenbroich, Marie Caroline; Sacconi, Leonardo; Pavone, Francesco S.

2015-07-01

Large volumes imaging with microscopic resolution is limited by light scattering. In the last few years based on refractive index matching, different clearing approaches have been developed. Organic solvents and water-based optical clearing agents have been used for optical clearing of entire mouse brain. Although these methods guarantee high transparency and preservation of the fluorescence, though present other non-negligible limitations. Tissue transformation by CLARITY allows high transparency, whole brain immunolabelling and structural and molecular preservation. This method however requires a highly expensive refractive index matching solution limiting practical applicability. In this work we investigate the effectiveness of a water-soluble clearing agent, the 2,2'-thiodiethanol (TDE) to clear mouse and human brain. TDE does not quench the fluorescence signal, is compatible with immunostaining and does not introduce any deformation at sub-cellular level. The not viscous nature of the TDE make it a suitable agent to perform brain slicing during serial two-photon (STP) tomography. In fact, by improving penetration depth it reduces tissue slicing, decreasing the acquisition time and cutting artefacts. TDE can also be used as a refractive index medium for CLARITY. The potential of this method has been explored by imaging a whole transgenic mouse brain with the light sheet microscope. Moreover we apply this technique also on blocks of dysplastic human brain tissue transformed with CLARITY and labeled with different antibody. This clearing approach significantly expands the application of single and two-photon imaging, providing a new useful method for quantitative morphological analysis of structure in mouse and human brain.

Analysis of Mammalian Sphingolipids by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) and Tissue Imaging Mass Spectrometry (TIMS)

PubMed Central

Sullards, M. Cameron; Liu, Ying; Chen, Yanfeng; Merrill, Alfred H.

2011-01-01

Sphingolipids are a highly diverse category of molecules that serve not only as components of biological structures but also as regulators of numerous cell functions. Because so many of the structural features of sphingolipids give rise to their biological activity, there is a need for comprehensive or “sphingolipidomic” methods for identification and quantitation of as many individual subspecies as possible. This review defines sphingolipids as a class, briefly discusses classical methods for their analysis, and focuses primarily on liquid chromatography tandem mass spectrometry (LC-MS/MS) and tissue imaging mass spectrometry (TIMS). Recently, a set of evolving and expanding methods have been developed and rigorously validated for the extraction, identification, separation, and quantitation of sphingolipids by LC-MS/MS. Quantitation of these biomolecules is made possible via the use of an internal standard cocktail. The compounds that can be readily analyzed are free long-chain (sphingoid) bases, sphingoid base 1-phosphates, and more complex species such as ceramides, ceramide 1-phosphates, sphingomyelins, mono- and di-hexosylceramides sulfatides, and novel compounds such as the 1-deoxy- and 1-(deoxymethyl)-sphingoid bases and their N-acyl-derivatives. These methods can be altered slightly to separate and quantitate isomeric species such as glucosyl/galactosylceramide. Because these techniques require the extraction of sphingolipids from their native environment, any information regarding their localization in histological slices is lost. Therefore, this review also describes methods for TIMS. This technique has been shown to be a powerful tool to determine the localization of individual molecular species of sphingolipids directly from tissue slices. PMID:21749933

Neural stem cells rescue nervous purkinje neurons by restoring molecular homeostasis of tissue plasminogen activator and downstream targets.

PubMed

Li, Jianxue; Imitola, Jaime; Snyder, Evan Y; Sidman, Richard L

2006-07-26

Neural stem cells (NSCs) offer special therapeutic prospects because they can be isolated from the CNS, expanded ex vivo, and re-implanted into diseased CNS where they not only migrate and differentiate according to cues from host tissue but also appear to be capable of affecting host cells. In nervous (nr) mutant mice Purkinje neuron (PN) mitochondria become abnormal by the second postnatal week, and a majority of PNs die in the fourth to fifth weeks. We previously identified in nr cerebellum a 10-fold increase in tissue plasminogen activator (tPA) as a key component of the mechanism causing nr PN death. Here we report that undifferentiated wild-type murine NSCs, when transplanted into the newborn nr cerebellar cortex, do not replace host PNs but contact imperiled PNs and support their mitochondrial function, dendritic growth, and synaptogenesis, subsequently leading to the rescue of host PNs and restoration of motor coordination. This protection of nr PNs also is verified by an in vitro organotypic slice model in which nr cerebellar slices are cocultured with NSCs. Most importantly, the integrated NSCs in young nr cerebellum rectify excessive tPA mRNA and protein to close to normal levels and protect the mitochondrial voltage-dependent anion channel and neurotrophins, downstream targets of the tPA/plasmin proteolytic system. This report demonstrates for the first time that NSCs can rescue imperiled host neurons by rectifying their gene expression, elevating somatic stem cell therapeutic potential beyond solely cell replacement strategy.

Correlation between a 2D Channelized Hotelling Observer and Human Observers in a Low-contrast Detection Task with Multi-slice Reading in CT

PubMed Central

Yu, Lifeng; Chen, Baiyu; Kofler, James M.; Favazza, Christopher P.; Leng, Shuai; Kupinski, Matthew A.; McCollough, Cynthia H.

2017-01-01

Purpose Model observers have been successfully developed and used to assess the quality of static 2D CT images. However, radiologists typically read images by paging through multiple 2D slices (i.e. multi-slice reading). The purpose of this study was to correlate human and model observer performance in a low-contrast detection task performed using both 2D and multi-slice reading, and to determine if the 2D model observer still correlate well with human observer performance in multi-slice reading. Methods A phantom containing 18 low-contrast spheres (6 sizes × 3 contrast levels) was scanned on a 192-slice CT scanner at 5 dose levels (CTDIvol = 27, 13.5, 6.8, 3.4, and 1.7 mGy), each repeated 100 times. Images were reconstructed using both filtered-backprojection (FBP) and an iterative reconstruction (IR) method (ADMIRE, Siemens). A 3D volume of interest (VOI) around each sphere was extracted and placed side-by-side with a signal-absent VOI to create a 2-alternative forced choice (2AFC) trial. Sixteen 2AFC studies were generated, each with 100 trials, to evaluate the impact of radiation dose, lesion size and contrast, and reconstruction methods on object detection. In total, 1600 trials were presented to both model and human observers. Three medical physicists acted as human observers and were allowed to page through the 3D volumes to make a decision for each 2AFC trial. The human observer performance was compared with the performance of a multi-slice channelized Hotelling observer (CHO_MS), which integrates multi-slice image data, and with the performance of previously validated CHO, which operates on static 2D images (CHO_2D). For comparison, the same 16 2AFC studies were also performed in a 2D viewing mode by the human observers and compared with the multi-slice viewing performance and the two CHO models. Results Human observer performance was well correlated with the CHO_2D performance in the 2D viewing mode (Pearson product-moment correlation coefficient R=0.972, 95% confidence interval (CI): 0.919 to 0.990) and with the CHO_MS performance in the multi-slice viewing mode (R=0.952, 95% CI: 0.865 to 0.984). The CHO_2D performance, calculated from the 2D viewing mode, also had a strong correlation with human observer performance in the multi-slice viewing mode (R=0.957, 95% CI: 879 to 0.985). Human observer performance varied between the multi-slice and 2D modes. One reader performed better in the multi-slice mode (p=0.013); whereas the other two readers showed no significant difference between the two viewing modes (p=0.057 and p=0.38). Conclusions A 2D CHO model is highly correlated with human observer performance in detecting spherical low contrast objects in multi-slice viewing of CT images. This finding provides some evidence for the use of a simpler, 2D CHO to assess image quality in clinically relevant CT tasks where multi-slice viewing is used. PMID:28555878

Transcriptional dysregulation causes altered modulation of inhibition by haloperidol.

PubMed

Brady, Lillian J; Bartley, Aundrea F; Li, Qin; McMeekin, Laura J; Hablitz, John J; Cowell, Rita M; Dobrunz, Lynn E

2016-12-01

Many neuropsychiatric and neurodevelopmental disorders such as schizophrenia and autism involve interneuron transcriptional dysregulation. The transcriptional coactivator PGC-1α regulates gene expression in GABAergic interneurons, which are important for regulating hippocampal network activity. Genetic deletion of PGC-1α causes a decrease in parvalbumin expression, similar to what is observed in schizophrenia postmortem tissue. Our lab has previously shown that PGC-1α -/- mice have enhanced GABAergic inhibition onto CA1 pyramidal cells, which increases the inhibition/excitation (I/E) ratio, alters hippocampal circuit function, and impairs hippocampal dependent behavior. The typical antipsychotic haloperidol, a dopamine receptor antagonist with selectivity for D2-like receptors, has previously been shown to increase excitation in the CA1 region of hippocampus. We therefore tested whether haloperidol could normalize the I/E balance in CA1 of PGC-1α -/- mice, potentially improving circuit function and behavior. Surprisingly, we discovered instead that interneuron transcriptional dysregulation caused by loss of PGC-1α alters the effects of haloperidol on hippocampal synaptic transmission and circuit function. Acute administration of haloperidol causes disinhibition in CA1 and decreases the I/E ratio onto CA1 pyramidal cells in slices from PGC-1α +/+ mice, but not PGC-1α -/- mice. The spread of activity in CA1, assessed by voltage sensitive dye imaging, is increased by haloperidol in slices from PGC-1α +/+ mice; however haloperidol decreases the spread of activity in slices from PGC-1α -/- mice. Haloperidol increased the power of hippocampal gamma oscillation in slices from PGC-1α +/+ mice but reduced the power of gamma oscillations in slices from PGC-1α -/- mice. Nest construction, an innate hippocampal-dependent behavior, is inhibited by haloperidol in PGC-1α +/+ mice, but not in PGC-1α -/- mice, which already have impaired nest building. The effects of haloperidol are mimicked and occluded by a D2 receptor antagonist in slices from PGC-1α +/+ mice, and the effects of blocking D2 receptors are lost in slices from PGC-1α -/- mice, although there is no change in D2 receptor transcript levels. Together, our results show that hippocampal inhibitory synaptic transmission, CA1 circuit function, and hippocampal dependent behavior are modulated by the antipsychotic haloperidol, and that these effects of haloperidol are lost in PGC-1α -/- mice. These results have implications for the treatment of individuals with conditions involving PGC-1α deficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transcriptional dysregulation causes altered modulation of inhibition by haloperidol

PubMed Central

Brady, Lillian J.; Bartley, Aundrea F.; Li, Qin; McMeekin, Laura J.; Hablitz, John J.; Cowell, Rita M.; Dobrunz, Lynn E.

2016-01-01

Many neuropsychiatric and neurodevelopmental disorders such as schizophrenia and autism involve interneuron transcriptional dysregulation. The transcriptional coactivator PGC-1α regulates gene expression in GABAergic interneurons, which are important for regulating hippocampal network activity. Genetic deletion of PGC-1α causes a decrease in parvalbumin expression, similar to what is observed in schizophrenia postmortem tissue. Our lab has previously shown that PGC-1α−/− mice have enhanced GABAergic inhibition onto CA1 pyramidal cells, which increases the inhibition/excitation (I/E) ratio, alters hippocampal circuit function, and impairs hippocampal dependent behavior. The typical antipsychotic haloperidol, a dopamine receptor antagonist with selectivity for D2-like receptors, has previously been shown to increase excitation in the CA1 region of hippocampus. We therefore tested whether haloperidol could normalize the I/E balance in CA1 of PGC-1α−/− mice, potentially improving circuit function and behavior. Surprisingly, we discovered instead that interneuron transcriptional dysregulation caused by loss of PGC-1α alters the effects of haloperidol on hippocampal synaptic transmission and circuit function. Acute administration of haloperidol causes disinhibition in CA1 and decreases the I/E ratio onto CA1 pyramidal cells in slices from PGC-1α+/+ mice, but not PGC-1α−/− mice. The spread of activity in CA1, assessed by voltage sensitive dye imaging, is increased by haloperidol in slices from PGC-1α+/+ mice; however haloperidol decreases the spread of activity in slices from PGC-1α−/− mice. Haloperidol increased the power of hippocampal gamma oscillation in slices from PGC-1α+/+ mice but reduced the power of gamma oscillations in slices from PGC-1α−/− mice. Nest construction, an innate hippocampal-dependent behavior, is inhibited by haloperidol in PGC-1α+/+ mice, but not in PGC-1α−/− mice, which already have impaired nest building. The effects of haloperidol are mimicked and occluded by a D2 receptor antagonist in slices from PGC-1α+/+ mice, and the effects of blocking D2 receptors are lost in slices from PGC-1α−/− mice, although there is no change in D2 receptor transcript levels. Together, our results show that hippocampal inhibitory synaptic transmission, CA1 circuit function, and hippocampal dependent behavior are modulated by the antipsychotic haloperidol, and that these effects of haloperidol are lost in PGC-1α−/− mice. These results have implications for the treatment of individuals with conditions involving PGC-1α deficiency. PMID:27480797

Inter-slice Leakage Artifact Reduction Technique for Simultaneous Multi-Slice Acquisitions

PubMed Central

Cauley, Stephen F.; Polimeni, Jonathan R.; Bhat, Himanshu; Wang, Dingxin; Wald, Lawrence L.; Setsompop, Kawin

2015-01-01

Purpose Controlled aliasing techniques for simultaneously acquired EPI slices have been shown to significantly increase the temporal efficiency for both diffusion-weighted imaging (DWI) and fMRI studies. The “slice-GRAPPA” (SG) method has been widely used to reconstruct such data. We investigate robust optimization techniques for SG to ensure image reconstruction accuracy through a reduction of leakage artifacts. Methods Split slice-GRAPPA (SP-SG) is proposed as an alternative kernel optimization method. The performance of SP-SG is compared to standard SG using data collected on a spherical phantom and in-vivo on two subjects at 3T. Slice accelerated and non-accelerated data were collected for a spin-echo diffusion weighted acquisition. Signal leakage metrics and time-series SNR were used to quantify the performance of the kernel fitting approaches. Results The SP-SG optimization strategy significantly reduces leakage artifacts for both phantom and in-vivo acquisitions. In addition, a significant boost in time-series SNR for in-vivo diffusion weighted acquisitions with in-plane 2× and slice 3× accelerations was observed with the SP-SG approach. Conclusion By minimizing the influence of leakage artifacts during the training of slice-GRAPPA kernels, we have significantly improved reconstruction accuracy. Our robust kernel fitting strategy should enable better reconstruction accuracy and higher slice-acceleration across many applications. PMID:23963964

Separation of parallel encoded complex-valued slices (SPECS) from a single complex-valued aliased coil image.

PubMed

Rowe, Daniel B; Bruce, Iain P; Nencka, Andrew S; Hyde, James S; Kociuba, Mary C

2016-04-01

Achieving a reduction in scan time with minimal inter-slice signal leakage is one of the significant obstacles in parallel MR imaging. In fMRI, multiband-imaging techniques accelerate data acquisition by simultaneously magnetizing the spatial frequency spectrum of multiple slices. The SPECS model eliminates the consequential inter-slice signal leakage from the slice unaliasing, while maintaining an optimal reduction in scan time and activation statistics in fMRI studies. When the combined k-space array is inverse Fourier reconstructed, the resulting aliased image is separated into the un-aliased slices through a least squares estimator. Without the additional spatial information from a phased array of receiver coils, slice separation in SPECS is accomplished with acquired aliased images in shifted FOV aliasing pattern, and a bootstrapping approach of incorporating reference calibration images in an orthogonal Hadamard pattern. The aliased slices are effectively separated with minimal expense to the spatial and temporal resolution. Functional activation is observed in the motor cortex, as the number of aliased slices is increased, in a bilateral finger tapping fMRI experiment. The SPECS model incorporates calibration reference images together with coefficients of orthogonal polynomials into an un-aliasing estimator to achieve separated images, with virtually no residual artifacts and functional activation detection in separated images. Copyright © 2015 Elsevier Inc. All rights reserved.

Impacts of simultaneous multislice acquisition on sensitivity and specificity in fMRI.

PubMed

Risk, Benjamin B; Kociuba, Mary C; Rowe, Daniel B

2018-05-15

Simultaneous multislice (SMS) imaging can be used to decrease the time between acquisition of fMRI volumes, which can increase sensitivity by facilitating the removal of higher-frequency artifacts and boosting effective sample size. The technique requires an additional processing step in which the slices are separated, or unaliased, to recover the whole brain volume. However, this may result in signal "leakage" between aliased locations, i.e., slice "leakage," and lead to spurious activation (decreased specificity). SMS can also lead to noise amplification, which can reduce the benefits of decreased repetition time. In this study, we evaluate the original slice-GRAPPA (no leak block) reconstruction algorithm and acceleration factor (AF = 8) used in the fMRI data in the young adult Human Connectome Project (HCP). We also evaluate split slice-GRAPPA (leak block), which can reduce slice leakage. We use simulations to disentangle higher test statistics into true positives (sensitivity) and false positives (decreased specificity). Slice leakage was greatly decreased by split slice-GRAPPA. Noise amplification was decreased by using moderate acceleration factors (AF = 4). We examined slice leakage in unprocessed fMRI motor task data from the HCP. When data were smoothed, we found evidence of slice leakage in some, but not all, subjects. We also found evidence of SMS noise amplification in unprocessed task and processed resting-state HCP data. Copyright © 2018 Elsevier Inc. All rights reserved.

The Utility of Thin Slice Ratings for Predicting Language Growth in Children with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Walton, Katherine M.; Ingersoll, Brooke R.

2016-01-01

Literature on "Thin Slice" ratings indicates that a number of personality characteristics and behaviors can be accurately predicted by ratings of very short segments (<5?min) of behavior. This study examined the utility of Thin Slice ratings of young children with autism spectrum disorder for predicting developmental skills and…

A simple one-step method to prepare fluorescent carbon dots and their potential application in non-invasive glioma imaging

NASA Astrophysics Data System (ADS)

Ruan, Shaobo; Qian, Jun; Shen, Shun; Zhu, Jianhua; Jiang, Xinguo; He, Qin; Gao, Huile

2014-08-01

Fluorescent carbon dots (CD) possess impressive potential in bioimaging because of their low photobleaching, absence of optical blinking and good biocompatibility. However, their relatively short excitation/emission wavelengths restrict their application in in vivo imaging. In the present study, a kind of CD was prepared by a simple heat treatment method using glycine as the only precursor. The diameter of CD was lower than 5 nm, and the highest emission wavelength was 500 nm. However, at 600 nm, there was still a relatively strong fluorescent emission, suggesting CD could be used for in vivo imaging. Additionally, several experiments demonstrated that CD possessed good serum stability and low cytotoxicity. In vitro, CD could be taken up into C6 glioma cells in a time- and concentration-dependent manner, with both endosomes and mitochondria involved. In vivo, CD could be used for non-invasive glioma imaging because of its high accumulation in the glioma site of the brain, which was demonstrated by both in vivo imaging and ex vivo tissue imaging. Furthermore, the fluorescent distribution in tissue slices also showed CD distributed in glioma with high intensity, while with a low intensity in normal brain tissue. In conclusion, CD were prepared using a simple method with relatively long excitation and emission wavelengths and could be used for non-invasive glioma imaging.Fluorescent carbon dots (CD) possess impressive potential in bioimaging because of their low photobleaching, absence of optical blinking and good biocompatibility. However, their relatively short excitation/emission wavelengths restrict their application in in vivo imaging. In the present study, a kind of CD was prepared by a simple heat treatment method using glycine as the only precursor. The diameter of CD was lower than 5 nm, and the highest emission wavelength was 500 nm. However, at 600 nm, there was still a relatively strong fluorescent emission, suggesting CD could be used for in vivo imaging. Additionally, several experiments demonstrated that CD possessed good serum stability and low cytotoxicity. In vitro, CD could be taken up into C6 glioma cells in a time- and concentration-dependent manner, with both endosomes and mitochondria involved. In vivo, CD could be used for non-invasive glioma imaging because of its high accumulation in the glioma site of the brain, which was demonstrated by both in vivo imaging and ex vivo tissue imaging. Furthermore, the fluorescent distribution in tissue slices also showed CD distributed in glioma with high intensity, while with a low intensity in normal brain tissue. In conclusion, CD were prepared using a simple method with relatively long excitation and emission wavelengths and could be used for non-invasive glioma imaging. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr02657h

A Nanostructured Matrices Assessment to Study Drug Distribution in Solid Tumor Tissues by Mass Spectrometry Imaging

PubMed Central

Giordano, Silvia; Pifferi, Valentina; Morosi, Lavinia; Morelli, Melinda; Falciola, Luigi; Cappelletti, Giuseppe; Visentin, Sonja; Licandro, Simonetta A.; Frapolli, Roberta; Zucchetti, Massimo; Pastorelli, Roberta; Brunelli, Laura; D’Incalci, Maurizio; Davoli, Enrico

2017-01-01

The imaging of drugs inside tissues is pivotal in oncology to assess whether a drug reaches all cells in an adequate enough concentration to eradicate the tumor. Matrix-Assisted Laser Desorption Ionization Mass Spectrometry Imaging (MALDI-MSI) is one of the most promising imaging techniques that enables the simultaneous visualization of multiple compounds inside tissues. The choice of a suitable matrix constitutes a critical aspect during the development of a MALDI-MSI protocol since the matrix ionization efficiency changes depending on the analyte structure and its physico-chemical properties. The objective of this study is the improvement of the MALDI-MSI technique in the field of pharmacology; developing specifically designed nanostructured surfaces that allow the imaging of different drugs with high sensitivity and reproducibility. Among several nanomaterials, we tested the behavior of gold and titanium nanoparticles, and halloysites and carbon nanotubes as possible matrices. All nanomaterials were firstly screened by co-spotting them with drugs on a MALDI plate, evaluating the drug signal intensity and the signal-to-noise ratio. The best performing matrices were tested on control tumor slices, and were spotted with drugs to check the ion suppression effect of the biological matrix. Finally; the best nanomaterials were employed in a preliminary drug distribution study inside tumors from treated mice. PMID:28336905

Optical coherence tomography: A new strategy to image planarian regeneration

NASA Astrophysics Data System (ADS)

Lin, Yu-Sheng; Chu, Chin-Chou; Lin, Jen-Jen; Chang, Chien-Cheng; Wang, Chun-Chieh; Wang, Chiao-Yin; Tsui, Po-Hsiang

2014-09-01

The planarian is widely used as a model for studying tissue regeneration. In this study, we used optical coherence tomography (OCT) for the real-time, high-resolution imaging of planarian tissue regeneration. Five planaria were sliced transversely to produce 5 head and 5 tail fragments. During a 2-week regeneration period, OCT images of the planaria were acquired to analyze the signal attenuation rates, intensity ratios, and image texture features (including contrast, correlation, homogeneity, energy, and entropy) to compare the primitive and regenerated tissues. In the head and tail fragments, the signal attenuation rates of the regenerated fragments decreased from -0.2 dB/μm to -0.05 dB/μm, between Day 1 and Day 6, and then increased to -0.2 dB/μm on Day 14. The intensity ratios decreased to approximately 0.8 on Day 6, and increased to between 0.8 and 0.9 on Day 14. The texture parameters of contrast, correlation, and homogeneity exhibited trends similar to the signal attenuation rates and intensity ratios during the planarian regeneration. The proposed OCT parameters might provide biological information regarding cell apoptosis and the formation of a mass of new cells during planarian regeneration. Therefore, OCT imaging is a potentially effective method for planarian studies.

Effect of Carboxylmethyl Cellulose Coating and Osmotic Dehydration on Freeze Drying Kinetics of Apple Slices

PubMed Central

Rahimi, Jamshid; Singh, Ashutosh; Adewale, Peter Olusola; Adedeji, Akinbode A.; Ngadi, Michael O.; Raghavan, Vijaya

2013-01-01

The effect of different concentrations of sugar solution (hypertonic) (30%, 45% and 60% w/v) and carboxyl methyl cellulose (CMC) (0%, 1% and 2% w/v) coating on freeze drying of apple slices was studied. In total, nine treatments with respect to concentrations of hypertonic solution and coating layer were prepared to analyze their influence on the physical and chemical properties of freeze dried apple slices. It was observed that increase in the sugar solution concentration, decreased the moisture content of the apple slices significantly impacting its water activity, texture and sugar gain. Application of different concentrations of CMC coating had no significant effect on the properties of dried apple slices. A significant change was observed for color of CMC coated freeze dried apple slices pretreated with 60% sugar solution. Drying kinetics of pretreated apple slices were fitted by using two drying models, Newton’s and Page’s. Page’s model showed higher R-square and lower root mean square error (RSME) compared to Newton’s model. PMID:28239107

Low-dose CT for quantitative analysis in acute respiratory distress syndrome

DTIC Science & Technology

2013-08-31

noise of scans performed at 140, 60, 15 and 7.5 mAs corresponded to 10, 16, 38 and 74 Hounsfield Units , respectively. Conclusions: A reduction of...slice of a series, total lung volume, total lung tissue mass and frequency distribution of lung CT numbers expressed in Hounsfield Units (HU) were...tomography; HU: Hounsfield units ; CTDIvol: volumetric computed tomography dose index; DLP: dose length product; E: effective dose; SD: standard deviation

AFRRI Reports, Second Quarter 1992.

DTIC Science & Technology

1992-07-01

onvotoxbhavor The pension task), and oxotremorine -enhanced K+-evoked release and late effects of these particles on motor behavior. The of dopamine from...agonists, such as oxotremorine , can activate the het- tissue chopper, and the slices from each animal were placed into a small mreceptors. which potentiate...as well as the MATERIALS AND METHODS other components described above (pH 7.4). One chamber of the pair for each animal received 500 p0! oxotremorine

Amino acid metabolism in tumour-bearing mice.

PubMed Central

Rivera, S; Azcón-Bieto, J; López-Soriano, F J; Miralpeix, M; Argilés, J M

1988-01-01

Mice bearing the Lewis lung carcinoma showed a high tumour glutaminase activity and significantly higher concentrations of most amino acids than in both the liver and the skeletal muscle of the host. Tumour tissue slices showed a marked preference for glutamine, especially for oxidation of its skeleton to CO2. It is proposed that the metabolism of this particular carcinoma is focused on amino acid degradation, glutamine being its preferred substrate. PMID:3342022

Cavitation Induced Structural and Neural Damage in Live Brain Tissue Slices: Relevance to TBI

DTIC Science & Technology

2014-09-29

Conference & Exposition on Experimental &Applied Mechanics , Mohegan Sun , Uncasville, Connecticut, June 13-16, 2011. (c) Presentations Number of...Presentations: Non Peer-Reviewed Conference Proceeding publications (other than abstracts): 08/23/2012 13.00 Received Paper Sung Jin Lee, Jingjing Sun ...abstracts): (d) Manuscripts 08/31/2011 08/31/2011 Received Paper 3.00 6.00 Sung Jin Lee, Jingjing Sun , Michael King , Huikai Xie , Malisa Sarntinoranont1

Precision-cut tissue chips as an in vitro toxicology system

PubMed Central

Catania, J. M.; Pershing, A. M.; Gandolfi, A. J.

2007-01-01

Precision-cut tissue slices mimic specific organ toxicity because normal cellular heterogeneity and organ architecture are retained. To optimize the use of the smaller tissues of the mouse and to establish easy assays for tissue viability, a tissue chip based system was used to generate large numbers of samples from a single organ. Iodoacetamide (IAM), was used as a model toxicant, and assays for intracellular potassium (normalized to DNA content) were used to establish viability and toxicant susceptibility. Thereafter, assays that were more rapid and specific were pursued. Lysates from tissues incubated in 6-carboxyfluorescein fluoresced proportionately to concentrations of IAM, indicating disruption of cellular membranes. Similarly, FURA-2, a probe applied to lysates to measure calcium levels, fluoresced proportionately to IAM dosage. Monobromobimane, a fluorescent sulfhydryl probe, displayed a decrease in fluorescent intensity at higher IAM challenge; a finding confirmed with an absorbance assay with Ellman’s reagent. Importantly, the number of samples per organ/mouse was increased at least 3-fold and a significant time reduction per analysis was realized. PMID:17376647

A simple model for deep tissue attenuation correction and large organ analysis of Cerenkov luminescence imaging

NASA Astrophysics Data System (ADS)

Habte, Frezghi; Natarajan, Arutselvan; Paik, David S.; Gambhir, Sanjiv S.

2014-03-01

Cerenkov luminescence imaging (CLI) is an emerging cost effective modality that uses conventional small animal optical imaging systems and clinically available radionuclide probes for light emission. CLI has shown good correlation with PET for organs of high uptake such as kidney, spleen, thymus and subcutaneous tumors in mouse models. However, CLI has limitations for deep tissue quantitative imaging since the blue-weighted spectral characteristics of Cerenkov radiation attenuates highly by mammalian tissue. Large organs such as the liver have also shown higher signal due to the contribution of emission of light from a greater thickness of tissue. In this study, we developed a simple model that estimates the effective tissue attenuation coefficient in order to correct the CLI signal intensity with a priori estimated depth and thickness of specific organs. We used several thin slices of ham to build a phantom with realistic attenuation. We placed radionuclide sources inside the phantom at different tissue depths and imaged it using an IVIS Spectrum (Perkin-Elmer, Waltham, MA, USA) and Inveon microPET (Preclinical Solutions Siemens, Knoxville, TN). We also performed CLI and PET of mouse models and applied the proposed attenuation model to correct CLI measurements. Using calibration factors obtained from phantom study that converts the corrected CLI measurements to %ID/g, we obtained an average difference of less that 10% for spleen and less than 35% for liver compared to conventional PET measurements. Hence, the proposed model has a capability of correcting the CLI signal to provide comparable measurements with PET data.

Impedance Spectrum in Cortical Tissue: Implications for Propagation of LFP Signals on the Microscopic Level

PubMed Central

Miceli, Stéphanie

2017-01-01

Brain research investigating electrical activity within neural tissue is producing an increasing amount of physiological data including local field potentials (LFPs) obtained via extracellular in vivo and in vitro recordings. In order to correctly interpret such electrophysiological data, it is vital to adequately understand the electrical properties of neural tissue itself. An ongoing controversy in the field of neuroscience is whether such frequency-dependent effects bias LFP recordings and affect the proper interpretation of the signal. On macroscopic scales and with large injected currents, previous studies have found various grades of frequency dependence of cortical tissue, ranging from negligible to strong, within the frequency band typically considered relevant for neuroscience (less than a few thousand hertz). Here, we performed a detailed investigation of the frequency dependence of the conductivity within cortical tissue at microscopic distances using small current amplitudes within the typical (neuro)physiological micrometer and sub-nanoampere range. We investigated the propagation of LFPs, induced by extracellular electrical current injections via patch-pipettes, in acute rat brain slice preparations containing the somatosensory cortex in vitro using multielectrode arrays. Based on our data, we determined the cortical tissue conductivity over a 100-fold increase in signal frequency (5–500 Hz). Our results imply at most very weak frequency-dependent effects within the frequency range of physiological LFPs. Using biophysical modeling, we estimated the impact of different putative impedance spectra. Our results indicate that frequency dependencies of the order measured here and in most other studies have negligible impact on the typical analysis and modeling of LFP signals from extracellular brain recordings. PMID:28197543