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OBJECTIVE: To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. METHODS: Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2alpha) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20alpha-OH and 20beta-OH) were monitored for a period of 5 weeks. RESULTS: Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). CONCLUSIONS: These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4.  相似文献   
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Furosemide premedication of horses 4 h prior to exercise significantly attenuates exercise-induced pulmonary capillary hypertension which may help diminish the severity of exercise-induced pulmonary haemorrhage. As pulmonary hemodynamic effects of furosemide may be mediated via a reduction in plasma volume (which is most pronounced 15-30 min postfurosemide administration, with plasma volume recovering thereafter), we hypothesized that administration of furosemide at intervals shorter than 4 h before exertion may be more effective in attenuating the exercise-induced rise in pulmonary capillary blood pressure. Thus, our objective was to determine whether furosemide-induced attenuation of exercise-induced pulmonary arterial, capillary and venous hypertension would be enhanced when the drug is administered at intervals shorter than 4 h before exercise. Using established techniques, right atrial, and pulmonary arterial, capillary and wedge (venous) pressures were ascertained in seven healthy, sound, exercise-trained Thoroughbred horses in a randomized split-plot experimental design. Measurements were made at rest and during exercise performed at maximal heart rate (217 +/- 3 beats/min) in the control (no medications) experiments and following furosemide administration (250 mg intravenously (i.v.)) at 1, 2, 3 and 4 h before exercise. Sequence of treatments was randomized and 7 days were allowed between experiments on each horse. Although furosemide administration in the four treatment groups caused only insignificant changes in the pulmonary arterial, capillary and wedge pressures of standing horses, furosemide-induced reduction in mean right atrial pressure achieved statistical significance in the 2 h postfurosemide experiments. In the control studies, exercise was attended by statistically significant increments in mean right atrial, as well as pulmonary arterial, capillary and wedge pressures. Although exercise in each of the four furosemide experiments was also attended by significant increments in right atrial as well as pulmonary vascular pressures, in the 1, 2 and 3 h postfurosemide experiments, mean right atrial pressure increased to a significantly lower value than in the control study. Exercise-induced changes in pulmonary vascular pressures in the 1 h postfurosemide experiments were not different from the pressures in the control study. There was a significant attenuation of exercise-induced pulmonary capillary and venous hypertension in the 2, 3 and 4 h postfurosemide experiments, but significant differences among these treatments were not found. Thus, these data did not support the contention that administration of furosemide at intervals shorter than 4 h before exercise is more effective in attenuating exercise-induced pulmonary capillary or venous hypertension in Thoroughbred horses.  相似文献   
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Cimetidine for treatment of melanomas in three horses   总被引:1,自引:0,他引:1  
Cimetidine, an H2 histamine antagonist, was used in the clinical management of progressive, multifocal melanomatosis in 3 adult gray horses. Prior to treatment, the tumors had increased rapidly in size and number in 2 horses (duration of 6 and 27 months, respectively) and slowly in the third horse (duration of 48 months). All 3 horses were treated with cimetidine (2.5 mg/kg of body weight, PO, q 8 h) for 2 months to 1 year. During treatment, the number and size of the melanomas decreased substantially (50 to 90%). The progression of the disease was halted in 2 horses and controlled in the third horse, which is still being treated with cimetidine (1.6 mg/kg, PO, q 24 h). The horses in which treatment was terminated have not been treated for 31 and 41 months, respectively, during which time the melanomas have not increased in number or size.  相似文献   
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【目的】 研究催乳素(PRL)对内蒙古绒山羊初级毛囊和次级毛囊体外生长及形态变化的影响。【方法】 机械法结合切割法分离内蒙古绒山羊的初级毛囊和次级毛囊,在初级毛囊培养液中分别添加0、5、10、50、100 ng/mL催乳素进行体外培养,每组24根,共培养5 d,每天在显微镜下观察其形态并拍照,统计其生长长度、生长速度和存活率,筛选出最适催乳素处理浓度。然后将初级毛囊与次级毛囊分别分为初级毛囊对照组(PF-K)、初级毛囊试验组(PF-PRL)、次级毛囊对照组(SF-K)、次级毛囊试验组(SF-PRL),每组24根,对照组用基础培养液培养,试验组在基础培养液中添加最适浓度的催乳素,培养5 d,每天观察毛囊的形态并拍照,同时测量各组毛囊的生长长度。【结果】 10 ng/mL催乳素组毛囊的平均日生长长度均极显著高于其他浓度组(P<0.01),最终生长长度和存活率均最高,因此,后续试验选择10 ng/mL催乳素处理毛囊。试验组和对照组初/次级毛囊的毛干与根鞘部位同时伸长,随着培养时间的增加均出现不同程度的弯曲。PF-PRL、SF-PRL组毛囊在2~5 d的总长度分别极显著高于PF-K、SF-K组(P<0.01)。PF-K组除第1天与第0天差异不显著外,1~5 d毛囊的总长度依次显著增加(P<0.05);PF-PRL组0~5 d毛囊的总长度依次显著增加(P<0.05)。SF-K组毛囊第5天的总长度显著高于0~4 d (P<0.05);SF-PRL组第4、5天毛囊的总长度均显著高于0~3 d (P<0.05),第3天毛囊的总长度显著高于0~2 d (P<0.05)。PF-PRL、SF-PRL组毛囊在2~5 d的平均日生长长度分别极显著高于PF-K、SF-K组(P<0.01)。【结论】 10 ng/mL催乳素是体外促进毛囊生长的最适浓度,10 ng/mL催乳素对体外培养的内蒙古绒山羊的初级毛囊和次级毛囊均有极显著的促生长作用。  相似文献   
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The plasma levels of estradiol-17 (E2), 17, 20-dihydroxy-4-pregnen-3-one (17,20-P) and gonadotropin (GTH) were measured in brook trout (Salvelinus fontinalis) during the period from the end of vitellogenesis to postovulation. Blood samples were taken according to specific stages of maturation, including germinal vesicle breakdown (GVBD) and ovulation. E2 levels were quite high (45 ng/ml) at the end of vitellogenesis (and prior to GVBD) and dropped precipitously by GVBD (2 ng/ml). They remained low through ovulation and postovulation. 17,20-P levels were low prior to GVBD (0.7 ng/ml) and increased dramatically at GVBD (148 ng/ml). The levels of 17,20-P remained high at ovulation (142 ng/ml) and then dropped significantly within 24 h to approximately half of the ovulatory values. They decreased even further by 7 days postovulation. GTH levels rose gradually through GVBD and ovulation from a postvitellogenic level of approximately 3 ng/ml to a 7 day postovulatory value of approximately 10 ng/ml. The overall results; 1) decrease in estradiol prior to GVBD, 2) increase in 17,20-P at GVBD and 3) gradual GTH rise through GVBD and ovulation, are similar to those reported for other salmonids.  相似文献   
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The effects of salmon angiotensin I (sAI) and human angiotensin II (hAII) on in vitro ovulation of preovulatory (preOV) brook trout (Salvelinus fontinalis) follicles were investigated. Both angiotensins increased levels of ovulation above that in controls after 12 hours of incubation. The increase was statistically significant in incubates with greater than 1 M hAII. The effects of the angiotensins on follicle contraction were also studied indirectly by measuring the decrease in weight of punctured follicles taken prior to germinal vesicle breakdown. At 1 M, both angiotensins significantly decreased the weight of punctured follicles after 16 hours of incubation. The angiotensin-stimulated decrease in weight was not blocked by indomethacin (10 g/ml), indicating that follicle contraction was not prostaglandin-dependent. The data indicate that angiotensins might be directly involved in brook trout ovulation and the stimulatory effects of angiotensins on ovulation may be attributed to their effects on follicle contraction.This work was supported by NIH grant #HD25924-02.  相似文献   
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