995 resultados para Tissue Preservation


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Mitochondrial reactive oxygen species generation has been implicated in the pathophysiology of ischemia-reperfusion (I/R) injury; however, its exact role and its spatial-temporal relationship with inflammation are elusive. Herein we explore the spatial-temporal relationship of oxidative/nitrative stress and inflammatory response during the course of hepatic I/R and the possible therapeutic potential of mitochondrial-targeted antioxidants, using a mouse model of segmental hepatic ischemia-reperfusion injury. Hepatic I/R was characterized by early (at 2h of reperfusion) mitochondrial injury, decreased complex I activity, increased oxidant generation in the liver or liver mitochondria, and profound hepatocellular injury/dysfunction with acute proinflammatory response (TNF-α, MIP-1α/CCL3, MIP-2/CXCL2) without inflammatory cell infiltration, followed by marked neutrophil infiltration and a more pronounced secondary wave of oxidative/nitrative stress in the liver (starting from 6h of reperfusion and peaking at 24h). Mitochondrially targeted antioxidants, MitoQ or Mito-CP, dose-dependently attenuated I/R-induced liver dysfunction, the early and delayed oxidative and nitrative stress response (HNE/carbonyl adducts, malondialdehyde, 8-OHdG, and 3-nitrotyrosine formation), and mitochondrial and histopathological injury/dysfunction, as well as delayed inflammatory cell infiltration and cell death. Mitochondrially generated oxidants play a central role in triggering the deleterious cascade of events associated with hepatic I/R, which may be targeted by novel antioxidants for therapeutic advantage.

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Different cell sources for bone tissue engineering are reviewed. In particular, adult cell source strategies have been based on the implantation of unfractionated fresh bone marrow; purified, culture expanded mesenchymal stem cells, differentiated osteoblasts, or cells that have been modified genetically to express rhBMP. Several limiting factors are mentioned for these strategies such as low number of available cells or possible immunological reaction of the host. Foetal bone cells are presented as an alternative solution and review of actual treatments using these cells is presented. Finally, foetal cells used specifically for bone tissue engineering are characterised and potentially interesting therapeutic options are proposed.

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Segment poses and joint kinematics estimated from skin markers are highly affected by soft tissue artifact (STA) and its rigid motion component (STARM). While four marker-clusters could decrease the STA non-rigid motion during gait activity, other data, such as marker location or STARM patterns, would be crucial to compensate for STA in clinical gait analysis. The present study proposed 1) to devise a comprehensive average map illustrating the spatial distribution of STA for the lower limb during treadmill gait and 2) to analyze STARM from four marker-clusters assigned to areas extracted from spatial distribution. All experiments were realized using a stereophotogrammetric system to track the skin markers and a bi-plane fluoroscopic system to track the knee prosthesis. Computation of the spatial distribution of STA was realized on 19 subjects using 80 markers apposed on the lower limb. Three different areas were extracted from the distribution map of the thigh. The marker displacement reached a maximum of 24.9mm and 15.3mm in the proximal areas of thigh and shank, respectively. STARM was larger on thigh than the shank with RMS error in cluster orientations between 1.2° and 8.1°. The translation RMS errors were also large (3.0mm to 16.2mm). No marker-cluster correctly compensated for STARM. However, the coefficient of multiple correlations exhibited excellent scores between skin and bone kinematics, as well as for STARM between subjects. These correlations highlight dependencies between STARM and the kinematic components. This study provides new insights for modeling STARM for gait activity.

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Membranes are dynamic structures that affect cell structure and function. Compositional changes ofmembranes have been shown with the application of a perturbation; however these are limited to whole tissue analysis. The purpose of this thesis was to compare the phospholipid (PL) fatty acid (FA) composition of rat whole muscle (Wm) to 1) purified and non-purified subsarcolemmal (SS) mitochondria in soleus, plantaris, and red gastrocnemius, and 2) sarcolemma, transverse-tubules, SS and intermyofibrillar (IMF) mitochondria fix)m whole hindlimb. The major findings were that 1) contamination significantly altered the PL FA composition of the SS mitochondrial membrane fraction, 2) Wm and SS mitochondria compositions differed between muscle types, and 3) Wm did not accurately reflect the PL FA composition of any isolated subcellular membranes, with each being unique from each other. As such, the relevancy of the trends reported in the literature of the effects of perturbations on Wm may be limited.

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Growth stimulation of Avena coleoptile tissue by indoleacetic acid (IAA) and fusicoccin (FC) was compared by measuring both their influence on RNA and protein synthesis during IAA or FC stimulated growth. FC stimulated growth more than IAA during the initial four hour exposure, after which the growth rate gradually declined to the control rate. FC, but not IAA, increased the uptake of 3H-Ieucine into tissue and the specific radioactivity of extracted protein. Cycloheximide inhibited the incorporation of 3H-Ieucine into protein by approximately 60% to 70% in all cases. In the presence of cycloheximide 3H-radioactivity accumulated in FC-treated tissue, whereas IAA did not seem to influence 3H-accumulation. These results suggest that FC stimulated leucine uptake into the tissue and that increased specific activity of coleoptile protein is due to increased leucine uptake, not an increased rate of protein synthesis. There was no measurable influence of IAA and/or FC on RNA and protein synthesis during the initial hours of a growth stimulation. Inhibitors of RNA and protein synthesis, actinomycin D and cycloheximide, respectively, severely inhibited IAA enhanced growth but only partially inhibited FC stimulated growth. The data are consistent with suggestions that a rapidly turning over protein participates in IAA stimulated growth, and that a continual synthesis of RNA and proteins is an absolute requirement for a long term growth response to IAA. On the contrary, FC-stimulated growth exhibited less dependency on the transcription and translation processes. The data are consistent with proposals suggesting different sites of action for FC and IAA stimulated growth. l?hen compared to CO2-free air, CO2 at 300 ppm had no significant influence on coleoptile growth and protein synthesis in the presence or absence of lAA or FC. Also, I mM malate, pH 6.0 did not influence growth of coleoptiles in the presence or absence of lAA. This result was obtained despite reports indicating that 300 ppm CO2 or I mM malate stimulates growth and protein synthesis. This lack of difference between CO2-treated and untreated tissue could indicate either that the interstitial space CO2 concentration is not actually different in the two treatments due to significant endogenous respiratory CO2 or else the data would suggest a very loose coupling between dark CO2 fixation and growth. IAA stimulated the in vivo fixation of 14c-bicarbonate (NaHI4c03) by about 25% and the addition of cycloheximide caused an inhibition of bicarbonate fixation within 30 min. Cycloheximide has also been reported to inhibit IAA-stimulated H+ excretion. These data are consistent with the acid growth theory and suggest that lAA stimulated growth involves dark CO2 fixation. The roles of dark CO2 fixation in lAA-stimulated growth are discussed.

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Photocopy.

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Title from spine.

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A manual instructing on the "Care and Preservation of Artillery Material" from the Field Artillery School of Instruction (Saumur). The name of Arthur A. Schmon is handwritten across the front cover.

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The Interlake Tissue Mills storage location was at the intersection of Glendale and Merritt Street in Merritton. In the 1850s, the Beaver Cotton Mills (later Merritton Cotton Mills) was built. It was a frame building that burned down in 1881. A sandstone structure replaced the previous building. In 1906, the cotton mill closed and in 1912, the Independent Rubber Company took over the building. The mill was doubled in size. The rubber company remained there for ten years and then the building remained vacant until 1935. Interlake Tissue Mills acquired the building for storage purposes. A fire razed the larger of the plant’s buildings on Memorial Day weekend in 1961. After the fire, Domtar used the smaller building for storage for a short time. This is currently the site of the Keg Restaurant.

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Preservation of Agricultural Lands Society [PALS] held its first meeting at Brock University on June 21, 1976. Its first executive consisted of Robert Hoover, Rick Teather, Debbie Kehler and Bill Forster. Some objectives of the organization were "to seek the preservation of valuable farm areas from non-agricultural expansion and development and to foster development and support of federal, provinicial and local policy which will provide a secure financial future for farming." Gracia Janes and John Bacher are some of the organizations' well known advocates. The organization was active in raising public awareness of the issues surrounding encroaching development onto existing agricultural lands. The organization is still active today [2016] in educating the public and attempting to influence governments at all levels to protect valuable agricultural lands.

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Le testicule assure la production des spermatozoïdes et la sécrétion de la testostérone. Chaque fonction est assumée par un compartiment cellulaire distinct: l’épithélium séminifère et le tissu interstitiel. Le cholestérol, présent dans les deux compartiments, est un composé indispensable aux membranes cellulaires et un précurseur essentiel de la testostérone. Dans le compartiment interstitiel, environ 40 % du cholestérol utilisé pour la production hormonale est importé du sang à partir des lipoprotéines HDL et/ou LDL. Dans l’épithélium séminifère, la cellule de Sertoli assure le contrôle et le maintien de la spermatogenèse. Elle a la capacité de synthétiser du cholestérol à partir de l’acétate in vitro, néanmoins, il n’y a pas d’évidence qu’elle le fait in vivo. De plus il existe, au niveau des tubules séminifères, une barrière hémato-testiculaire qui empêche le libre passage de plusieurs composés sanguins, y compris le cholestérol. Nous avons testé l’hypothèse qu’il existe des moyens d’importation du cholestérol sanguin, mais aussi l’exportation du cholestérol intra-tissulaire, qui contourneraient cette barrière et qui contribueraient au maintien du taux intratubulaire du cholestérol compatible avec le bon déroulement de la spermatogenèse. Nous avons comparé les taux de variation de l’expression de l’ARNm et de la protéine des transporteurs sélectifs de cholestérol SR-BI, SR-BII, CD36 et ABCA1 aux taux de variation du cholestérol libre et estérifié au cours de la spermatogenèse chez les souris normales durant le développement postnatal. Afin de mieux apprécier le niveau d’implication de chacun de ces récepteurs, nous avons examiné comment la suppression du gène d’une enzyme comme la lypase hormono-sensible (HSL) ou de celui d’un transporteur de cholestérol comme SR-BI, CD36 ou NPC1 était compensée et comment cette suppression affectait le taux de cholestérol libre et estérifié dans chacun des deux compartiments cellulaires du testicule. Nous avons dans un premier temps mis au point une nouvelle technique d’isolation des testicules en fraction enrichie en tissu interstitiel (ITf) et en tubules séminifères (STf) qui a l’avantage de mieux préserver l’intégrité des formes phosphorylées et glycosylées des protéines comparée aux techniques préexistantes. Les résultats de nos analyses ont montré que l’expression de SR-BI et CD36 étaient maximales dans les ITf au moment où les souris ont complété leur maturité sexuelle et où le niveau de synthèse de la testostérone était maximal. Dans les tubules séminifères, l’expression maximale de SR-BI et le taux le plus élevé de cholestérol estérifié étaient mesurés de façon concomitante à 35 jours après la naissance, au moment où la première vague de l’activité spermatogénétique était complétée. L’expression de l’ABCA1 était maximale au moment où le taux de cholestérol était élevé et minimale au moment où le taux de cholestérol était le plus bas, alors que le niveau d’expression de CD36 était maximal chez l’adulte au moment où le taux de spermiation était le plus élevé. L’expression de SR-BII variait peu dans les deux compartiments cellulaires durant le développement. La suppression génétique de la HSL et de NPC1, qui cause une infertilité chez les souris mâles, était accompagnée d’une accumulation de cholestérol libre et estérifié dans les tubules séminifères. Par contre, la suppression génétique de SR-BI et CD36, qui ne causent pas d’infertilité chez les souris mâles était sans impact significatif sur le taux de cholestérol intratubulaire. Nous avons montré que l’invalidation génétique d’un transporteur sélectif ou d’une enzyme du métabolisme du cholestérol était accompagnée d’un ensemble de mécanismes de compensation visant à maintenir le taux de cholestérol libre aux niveaux semblables à ceux mesurés dans les fractions tissulaires de souris normales. Ensemble, nos résultats ont montré que l’expression des transporteurs sélectifs de cholestérol SR-BI, SR-BII, CD36 et ABCA1 variait en fonction de la spermatogenèse et du taux intratesticulaire du cholestérol suggérant leur contribution au maintien de l’homéostasie du cholestérol intratesticulaire.