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91.
The main determinants of body size are GH and IGFs. The aim of this study was to investigate whether differences in adult body size of medium-sized and giant dog breeds can be explained by differences in GH release and/or in plasma IGF-I and IGF-II concentrations at a young age. The basal plasma concentrations of GH, IGF-I and IGF-II were determined once weekly in six Great Danes and six beagles from the age of 6 weeks until the age of 24 weeks. In addition, the 6 h secretory profile of GH was determined every 2 weeks. Basal plasma GH concentrations as well as the total area under the curve (AUC) and the AUC above the baseline for GH were significantly higher in Great Danes than in beagles of the same age. In contrast, plasma IGF-I and IGF-II concentrations did not differ significantly between the two breeds. Compared with values in adults, the basal plasma GH concentrations were high until the age of 7 weeks in the beagles, whereas in the Great Danes the basal plasma GH levels remained high during the entire observation period, albeit with a gradual decline. The mean frequency and the mean amplitude of GH pulses tended to be higher in Great Danes than in beagles, although a significant difference was only reached at the age of 19 and 23 weeks for the frequency and at the ages of 9, 11 and 13 weeks for the amplitude. An age-dependent decrease in pulse frequency occurred in the Great Danes. The results of this study demonstrate that differences in adult body size of medium-sized and giant dog breeds are preceded by differences in GH release and not by differences in circulating IGF-I or IGF-II concentrations. Both young Great Danes and young beagles experience a period of high GH release, but this period persists much longer in Great Danes. It is discussed that this difference may be due to delayed maturation of the inhibitory influences of somatostatin on pituitary GH release in the latter dogs. 相似文献
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OBJECTIVE: To determine the prognostic significance of laparoscopy results for fertility outcome. STUDY DESIGN: Consecutive patients undergoing hysterosalpingography and laparoscopy for subfertility in our department between May 1985 and November 1987 were identified from medical records. The impact of tubal occlusion, hydrosalpinx and adhesions as detected at laparoscopy was studied. Kaplan-Meier curves for the occurrence of spontaneous intrauterine pregnancy were constructed for patients without tubal pathology, with mild tubal pathology (unilateral pathology or adhesions) and with severe tubal pathology (bilateral pathology). Fecundity rate ratios (FRR) were calculated to express the association between findings at laparoscopy and the occurrence of spontaneous intrauterine pregnancy. RESULTS: Of the 200 cases that could be analyzed, 129 (65%) showed no tubal occlusion on laparoscopy, 40 (20%) had unilateral tubal occlusion, and 31 (15%) had bilateral tubal occlusion. Unilateral hydrosalpinx was present in 13 (7%) patients, whereas 19 (10%) patients had bilateral hydrosalpinx. Adjusted FRRs were 0.65 and 0.20 for unilateral and bilateral tubal occlusion, and 0.46 and 0.32 for unilateral and bilateral hydrosalpinx. Peritubal adhesions were detected in 43% of patients and seemed to have no prognostic significance. CONCLUSION: Severe tubal pathology detected at laparoscopy affects fertility prospects strongly. However, since spontaneous intrauterine pregnancies occurred even in patients with bilateral tubal occlusion at laparoscopy, this technique should not be considered the gold standard in the diagnosis of tubal infertility. 相似文献
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W E Mol F Rombout J E Paanakker R Oosting A H Scaf D K Meijer 《Biochemical pharmacology》1992,44(7):1453-1459
Both in humans and animals hepatic elimination is an important factor determining the duration of action of non-depolarizing neuromuscular blocking drugs. To elucidate the hepato-biliary disposition of muscle relaxants the pharmacokinetics of several structurally related but physicochemically distinct steroidal neuromuscular blocking drugs were studied in isolated perfused rat livers. Pharmacokinetics analysis with the DIFFIT computer program enabled the simultaneous fitting of independently measured perfusate disappearance and biliary excretion rate curves using a numerical approach. The hepatic disposition of the steroidal muscle relaxants could be adequately described by a three compartment model with elimination from the peripheral compartment V2 (biliary excretion) and storage in a deep compartment (V3) connected to V2. In addition, for vecuronium only slow ester hydrolysis occurring in V2 and V3 was included in the model. The lipophilicity rather than the relative mobility of the muscle relaxants showed a positive relationship with biliary clearance (Cl20) and the initial hepatic uptake (Cl12), indicating that hepato-biliary transport of these organic cations is highly dependent on the hydrophobic character of the compounds. In addition, net hepatic uptake of the steroidal cations was influenced markedly by transport from the liver to perfusate (hepatic efflux). This hepatic efflux (k21) decreased with increasing lipophilicity. In contrast, the extent of intracellular sequestration into deep compartments, indicated by high k23/k32 ratios, seemed to be inversely related to the lipophilicity of the muscle relaxants and might explain the observed prolonged hepatic storage of some of these compounds. In combination with data from subfractionation studies the results indicate that the pharmacokinetic analysis of the hepatic disposition of steroidal muscle relaxants may be used to evaluate actual transport phenomena participating in the hepatic disposition of these drugs. 相似文献
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The fat embolism syndrome 总被引:3,自引:0,他引:3
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