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1.
The aim of this study was to evaluate the effect of leptin administration during superovulation on in vivo goat embryo production. Ten mature does were superovulated with 133 mg follicle‐stimulating hormone (FSH) i.m. in six descending doses at 12‐h intervals. The goats received 4.8 μg/kg human recombinant leptin s.c. (leptin group, n = 5) or phosphate‐buffered saline (PBS) (control group, n = 5) with the first and second FSH doses. The does were mated and subjected to embryo collection by transcervical technique 6 days later. The total number of cells per embryo and the number of cells with fragmented DNA were assessed in selected blastocysts by combining Hoechst 33342 and terminal dUTP nick‐end labelling (TUNEL) staining. Plasma concentrations of oestradiol (E2) and progesterone (P4) were determined by electrochemiluminescence from the day of FSH treatment, on the day of superovulatory oestrus and on the day before embryo collection. Compared with the control group, the does that received leptin had a higher number of transferable embryos (p < 0.005), fewer embryos classified as degenerated (p < 0.001) and fewer TUNEL‐positive cells/blastocyst (p < 0.001). The number of transferable embryos was positively correlated with E2 concentrations on day of oestrus (r = 0.562; p < 0.01) and P4 concentrations on the day of embryo collection (r = 0.912; p < 0.001). We concluded that in vivo leptin administration during FSH treatment improved embryo quality and affected ovarian steroidogenesis in superovulated goats.  相似文献   
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Objective The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Procedures A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. Results In the paddocks used (0.8–16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Conclusions Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.  相似文献   
3.
Radiation carcinogenesis: the sequence of events   总被引:4,自引:0,他引:4  
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Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.  相似文献   
6.
The T-cell receptor is formed by two chains, alpha and beta, for which specific clones were recently obtained. In this report the gene for the beta chain of the human T-cell receptor was located on the long arm of chromosome 7, band q35, by means of in situ hybridization. This chromosome region in T cells is unusually prone to develop breaks in vivo, perhaps reflecting instability generated by somatic rearrangement of T-cell receptor genes during normal differentiation in this cell lineage.  相似文献   
7.
The crystal structures of a number of fungicidal azolylmethanes are compared. In the benzyl compounds [1-aryl-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ones, the corresponding pentan-3-ols, and 1-(4-chlorophenyl)-3-(2-fluorophenyl)-2-(1,2,4-triazol-1-yl)propan-1-one], the benzyl and tert-butyl groups (or 4-chlorophenyl group) are trans, whereas in the analogous phenoxy compounds [1-(4-chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)butan-2-one and the corresponding butan-2-ol], the tert-butyl groups are trans to the triazole and gauche to the phenoxy group. Coupling constants, determined by nuclear magnetic resonance (n.m.r.) spectroscopy, suggest that for some compounds there is one dominant solution conformation. Intramolecular hydrogen bonding, observed by infrared spectroscopy in two of the compounds, supports the findings by n.m.r. For some compounds, the crystal and solution conformations appear to be very similar, whereas in others they are quite different. Published data on the relative activity of the enantiomers of the benzyl- and phenoxy-compounds are discussed, but differences in the relative activity of enantiomers in the two series cannot be readily rationalised. It is concluded that different enantiomers may have different modes of binding at the active site.  相似文献   
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AIM: To develop a technique to estimate the volume of epithelial lining fluid (ELF) obtained during bronchoalveolar lavage (BAL) and pleural lavage (PL) in the dog, using the urea dilution method.

METHODS: BAL and PL fluids were obtained by saline lavage of pulmonary and pleural cavities of nine clinically healthy mixed-breed dogs immediately after euthanasia. Cell counts in the BAL and PL fluids were measured using standard techniques. The concentration of ELF in each lavage fluid was calculated from the relative concentration of urea in plasma and in each type of lavage fluid. Cell counts in ELF were then calculated.

RESULTS: There were substantially higher cell counts in ELF compared to BAL or PF fluid. However, nucleated cell counts in ELF could not be predicted from cell counts in BAL or PL fluid.

CONCLUSIONS AND CLINICAL RELEVANCE: These results suggest that accurate assessment of cellular or non-cellular components in lavage fluids should include a calculation of the proportion of ELF recovered, using a method such as urea dilution.  相似文献   
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