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The goal of the current study was to compare the efficiency of gas exchange and platelet conservation of a new extracapillary blood flow oxygenator versus an endocapillary blood flow oxygenator during open heart surgery with extracorporeal circulation in dogs. Dilation and remodeling of the right ventricular outflow tract of dogs was performed using a patch graft technique to simulate pulmonary stenosis. Sequential pre- and post-operative blood analysis revealed that gas exchange efficiency and platelet conservation was significantly greater with the extracapillary blood flow oxygenator than with the endocapillary blood flow oxygenator. However, the priming volume of the extracapillary blood flow oxygenator was significantly greater, leading to hemodilution. We conclude that while the extracapillary blood flow oxygenator provided benefits in terms of gas exchange and platelet conservation, development of a smaller extracapillary blood flow type oxygenator to reduce hemodilution effects would be beneficial.  相似文献   
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Real‐time polymerase chain reaction (PCR) assays for 11 representative rumen bacterial species were validated. The sensitivity was tested by using the serially diluted target 16S rDNA from respective bacterial species. The recovery of the target DNA and the assay reproducibility were determined using DNA from rumen fluid spiked with different quantities of the target. Minimum detection levels for the target were 10–100 copies in pure culture. The recovery of the added target ranged from 82.4 to 116.6%. The intra‐ and inter‐assay variations of each assay were <9.4 and <12.6%, respectively. Therefore, the real‐time PCR assays evaluated in the present study are considered to be sufficiently reliable for monitoring all 11 bacterial species in the rumen. The assays were then applied to the monitoring of the bacterial species attached to ruminally incubated rice straw. Among the monitored fibrolytic species, Fibrobacter succinogenes was found to be the most dominant, accounting for 2.61% of total bacteria after 24 h incubation. Selenomonas ruminantium and Streptococcus bovis, non‐fibrolytics, were detected on the rice straw at 8.96% and 1.16% of total bacteria, respectively. Such high levels of non‐fibrolytics on the plant fiber suggest a synergistic relationship between fibrolytics and non‐fibrolytics.  相似文献   
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In a previous study, it was found that there are sex differences in goats with respect to the levels of cortisol secretion induced by transportation stress. We also found that treatment of castrated male goats with dihydrotestosterone (DHT) suppressed the increase in plasma cortisol concentration following transportation, but did not suppress the secretion of adrenocorticotropic hormone (ACTH). This suggests that androgen might block ACTH ‐ induced cortisol secretion. In order to examine this hypothesis, the effects of androgen on ACTH‐induced cortisol secretion in goats were investigated. First, castrated male goats were treated with testosterone (T), DHT or cholesterol (cho) for 21–25 days. Cho was used as a control for T and DHT treatment. Then, plasma cortisol concentrations were compared among the hormonal treatments after ACTH injection. Subsequently, the distribution of androgen receptors in the caprine adrenal gland was investigated. There were no differences in the basal cortisol concentrations among the hormonal treatments. However, plasma cortisol concentrations after ACTH injection were significantly lower in T ‐ and DHT ‐ treated goats than in cho ‐ treated goats. Androgen receptors were present in 60% of the cells in the zonae fasciculata and reticularis of the adrenal cortex, the regions that secrete glucocorticoids. These results suggest that androgen may act directly on the adrenal cortex to suppress cortisol secretion induced by ACTH.  相似文献   
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When animals do not become pregnant, regression of the corpus luteum (CL) is essential for normal cyclicity because it allows the development of a new ovulatory follicle. Luteal regression is caused by a pulsatile release of prostaglandin (PG) F from the uterus in the late luteal phase in most mammals including cattle. Although it has been proposed in ruminants that pulsatile PGF secretion is generated by a positive feedback loop between luteal and/or hypophyseal oxytocin and uterine PGF, the bovine endometrium may possess other mechanisms for initiation of luteolytic PGF secretion. There is increasing evidence that several cytokines mainly produced by immune cells modulate CL and uterine function in many species. Tumor necrosis factor‐α (TNF‐α) stimulates PGF output from bovine endometrium not only at the follicular phase but also at the late luteal phase. Administration of TNF‐α at a high concentration prolongs luteal lifespan, whereas administration of a low concentration of TNF‐α accelerates luteal regression in cows. The data obtained from the authors’ previous in vitro and in vivo studies strongly suggest that TNF‐α is a crucial factor in regulating luteolysis in cows. The authors’ recent study has shown that interleukin‐1α mediates PG secretion from bovine endometrium as a local regulator. Furthermore, interferon‐τ (IFN‐τ) suppresses the action of TNF‐α on PGF synthesis by the bovine endometrium in vitro, suggesting that IFN‐τ plays a luteoprotective role by inhibiting TNF‐α‐induced PGF production in early pregnancy. The purpose of the present review is to summarize current understanding of the endocrine mechanisms that regulate uterine function by cytokines during the estrous cycle and early pregnancy in cows.  相似文献   
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1. The effects of the beta-adrenergic agonist, clenbuterol (1 mg/kg diet) on the growth and muscle composition in female broiler chickens (14 to 32 d of age) fed on diets containing various concentrations of protein (220, 240 or 260 g protein/kg) were examined. 2. Body weight gain over the 18 d period increased linearly with increasing protein intake. The rate of gain was significantly higher in clenbuterol-treated chickens than in control birds. 3. Dietary clenbuterol increased thigh muscle weight and protein concentration of breast and thigh muscle, regardless of dietary protein content. Protein/DNA ratio in thigh muscle was enhanced by clenbuterol feeding, and the magnitude of difference of the ratio was higher in chickens fed on the 240 and 260 g CP/kg diets than in those fed the 220 g CP/kg diet. 4. It was concluded that clenbuterol-treated chickens require increased dietary protein to maintain maximal growth, and that increased protein consumption is an important factor in improving growth in clenbuterolfed broilers.  相似文献   
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