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21.
Tight junctions (TJs) in inter-Sertoli junctional areas and epididymal epithelia build up the blood–testis barrier (BTB) and the blood–epididymal barrier (BEB), respectively. In this study, the expression of occludin, an integral member of the TJs, was examined in testis and different regions of epididymis of Lepus sinensis coreanus , an Korean wild rabbit species. In testis, intense occludin immunoreactivity was found in the basally located inter-Sertoli junctional area together with diffused immunoreactivity of occludin in the cytoplasm of Sertoli cells. It can be suggested that occludin is one of the robust elements of BTB in seminiferous tubules of rabbit testis. In proximal and distal caput epididymis, occludin immunoreactivity was found in the lateral as well as apical contacts of epithelial cells. In corpus epididymis, intense occludin immunoreactivity was found in the basolateral as well as apical contacts of epithelial cells together with cytoplasmic signal. In cauda epididymis, occludin immunoreactivity in luminal epithelia was relatively strong but largely found in the cytoplasm. This suggests that intriguing regulatory mechanisms differentially recruit occludin to the TJ in the different regions of epididymal epithelia. The differences in the subcellular localization as well as expression levels of occludin among the epididymal segments may reflect differential paracellular permeability of epithelia along the epididymal tubules and be correlated with sperm maturation in rabbit. In Western blot, a major form of occludin was MW 62 kDa together with small fragments of MW 34–39 kDa in testis and epididymis, suggesting the peptide cleavage of occludin. This is the first report on the molecular nature of TJs in a wild rabbit testis and epididymis.  相似文献   
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The relationship between mixed venous O2 tension and cardiac output was studied in six anesthetized horses breathing 100% O2. Cardiac output, O2 consumption, mean arterial pressure, heart rate, and arterial and venous blood gases were measured after administration of xylazine or dobutamine to horses in lateral, sternal, and dorsal recumbencies. After approximately 3 hours, Escherichia coli endotoxin was administered while horses were in dorsal recumbency, and all measurements were repeated. Relationships between cardiac index (CI) and PVO2, heart rate, mean arterial pressure, jugular PVO2, and PVO2 of blood from a superficial limb vein were evaluated by linear regression analysis. Mean arterial pressure was significantly (P less than 0.05) correlated with CI in horses in all positions and after endotoxin administration. However, data points were poorly grouped. Heart rate and CI were significantly correlated in horses in all positions, but not after endotoxin administration. Correlations between jugular PVO2 and PVO2 of blood from a superficial limb vein were not significant in horses in sternal recumbency, and PVO2 of blood from a superficial limb vein was not significantly correlated with CI in horses in lateral recumbency. There was a significant and tight correlation between PVO2 and CI in horses in all positions and after endotoxin administration.  相似文献   
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OBJECTIVE: To determine whether autologous jugular veins provide functional grafts with high 30-day patency rates in an experimental model of systemic-to-pulmonary shunting performed with a modified Blalock-Taussig procedure. ANIMALS: 15 healthy Beagles. PROCEDURE: A segment of the left jugular vein was implanted between the left subclavian and pulmonary arteries. Echocardiograms were obtained prior to surgery, at day 4 to 7, and at day 30 after surgery. Selective angiograms were performed immediately after surgery and on day 30. Oximetric shunt calculations were made via terminal angiography prior to euthanasia. Gross and histologic evaluations of the grafts were conducted. RESULTS: Grafts were patent in 12 of 15 dogs 30 days after surgery as assessed via auscultation, color Doppler ultrasonography, angiography, and histologic examination. Echocardiographic analysis revealed compensatory eccentric left ventricular hypertrophy. Mean pulmonary-to-systemic flow ratio was 1.5:1. Histologic evidence of endothelialization of the anastomotic sites and vein graft arterialization was detectable at 30 days. CONCLUSIONS AND CLINICAL RELEVANCE: Autologous jugular vein grafts were effectively used to create a systemic-to-pulmonary shunt by use of a modified Blalock-Taussig procedure. High patency, ready accessibility, low cost, and theoretical adaptative remodeling during patient growth make autologous jugular vein grafts a valuable alternative to synthetic materials.  相似文献   
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A 9-year-old dog with spontaneous ascites was found to have hepatic vein distension and a tortuous vena cava on abdominal ultrasound. In right lateral recumbency, the caudal vena cava crossed the diaphragm and became kinked before entering into the right atrium. Following this observation, we performed an experimental study in a normal dog to determine whether kinking of the caudal vena cava could be the result and not the cause of ascites. Ascites was induced using warm saline injected through a needle inserted into the abdominal cavity. Venograms were collected from different body positions, under four conditions: before and after a total of one, two and 3 liters of saline had been injected. Caudal vena cava kinking was observed in the experimental dog after 2 liters of fluid had been injected. Vena cava obstruction may cause ascites, but we found that sometimes caudal vena cava kinking can be the result and not the cause of the peritoneal effusion.  相似文献   
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Digoxin administration (0.22 mg/m2 of body surface BID) to 10 large-breed dogs with congestive cardiomyopathy increased shortening fraction more than 5.5% in 4 of the dogs. This group of dogs lived longer than the group that did not have a positive inotropic response to digoxin. Heart rate decreased in both groups of dogs. Base-line jugular PVO2 were low in all dogs. Jugular PVO2 decreased significantly in the group that did not respond to digoxin, presumably because of decreased cardiac output. Jugular PVO2 consistently increased in dogs that had a positive inotropic response to digoxin. Base-line shortening fraction, heart rate, and PVO2 did not predict which dogs would respond to digoxin. Serum digoxin concentrations were consistently between 1.5 and 2.5 ng/ml. It was concluded that digoxin administration is not efficacious in all dogs with congestive cardiomyopathy and that the positive inotropic response is not predicted by base-line shortening fraction, heart rate, or jugular PVO2. Dogs that do respond to digoxin usually live longer than those that do not. Jugular PVO2 can be used to separate dogs that do respond from dogs that do not respond to digoxin as long as the base-line PVO2 is low. The negative chronotropic effects of digoxin may be detrimental to dogs that do not have a positive inotropic effect from digoxin.  相似文献   
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The effect of dobutamine on cardiac function of dogs was investigated. Sixteen dogs were submitted to cardiopulmonary bypass. The aorta of each dog was cross-clamped for 1 hour; attempt was not made to perfuse the heart. After 1 hour, 8 of the 16 dogs were randomly selected and treated with dobutamine (5 mug/kg/min). The other 8 dogs were designated the control group and were given placebo. Postperfusion failure and death were used as end point criteria. Dogs given dobutamine responded remarkably well, with significantly decreased postperfusion low output syndrome. Evidence of cardiac function 5 minutes after the removal of the bypass was the criterion used to determine survival of the surgical cross-clamp procedure; however, this did not necessarily indicate survival of the dog. Of the 8 dogs given dobutamine, 6 (75%) survived the surgical cross-clamp, whereas of the 8 dogs not given dobutamine, 3 (37.5%) survived the surgical procedure. Seemingly, the effect of dobutamine is not mainly chronotropic, but is rather a direct aid to myocardial strength.  相似文献   
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