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51.
J. H. S. Whyte 《BMJ (Clinical research ed.)》1944,1(4340):373-374
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Muthuvel Jayachandran Hiroya Okano Ritu Chatrath Whyte G Owen Joseph P McConnell Virginia M Miller 《Journal of applied physiology》2004,97(4):1445-1452
Cardiovascular disease may begin early in adolescence. Platelets release factors contributing to vascular disease. Experiments were designed to test the hypothesis that hormonal transitions associated with sexual maturity differentially affect platelet aggregation and secretion in males and females. Platelets were collected from juvenile (2-3 mo) and sexually mature (adult; 5-6 mo) male and female pigs (n=8/group). Maturation was evidenced by increased weight of reproductive tissue and changes in circulating levels of gonadal hormones. Aggregation to ADP (10 microM) and collagen (6 microg/ml) and ATP secretion to 50 nM thrombin were determined by turbidimetric analysis and bioluminescence, respectively. Total platelet counts, platelet turnover, and mean platelet volume did not change with maturity. Platelet aggregation and ATP secretion decreased in females but increased in males with maturity, whereas total ATP content remained unchanged in platelets from females but increased in platelets from males. Platelet fibrinogen receptor, P-selectin expression, and receptors for sex steroids did not change with sexual maturation. Plasma C-reactive protein and brain-type natriuretic peptide also did not change. Results indicate that changes in platelet aggregation and secretion change with sexual maturity differently in females and males. These observations provide evidence on which clinical studies could be designed to examine platelet characteristics in human children and young adults. 相似文献
55.
Landscape heterogeneity may influence ranging behaviour of mammals. Here we relate the home range size of elephants living in the Kruger National Park to the number of patches, proportion of each patch, spatial arrangement of patches, patch shape, and contrast between neighbouring patches. Home range sizes decreased exponentially with an increase in the number of patches per 100 km2 and the home range sizes of bulls were in general more strongly related to measures of heterogeneity. This may reflect differences in perception of heterogeneity between the sexes. 相似文献
56.
Raised fasting blood lactate levels were observed in diabetic patients on phenformin in therapeutic dosage. After an intravenous glucose load this effect was exaggerated and the lactate/pyruvate ratio increased. Withdrawal of the drug led to normal blood lactate levels and a fall in the lactate/pyruvate ratio. 相似文献
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Lyle G. Whyte Luc Bourbonni re Claude Bellerose Charles W. Greer 《Bioremediation Journal》1999,3(1):69-80
The bioremediation potential of hydrocarbon-contaminated soils from the most northerly inhabited station in the world, Canadian Forces Station - Alert, was assessed. Microbial enumeration, by both viable plate counts and direct counts, combined with molecular analysis (polymerase chain reaction and colony hybridization) for hydrocarbon catabolic genes (alkB, ndoB, xylE), demonstrated the presence of significant numbers of cold-adapted hydrocarbon-degrading microorganisms. The degradative activity of these populations was assessed by mineralization of 14Clabeled hexadecane (C16) at 5°C in untreated and treated soils. Although very low rates of C16 mineralization were observed in the untreated soils, nutrient supplementation with a fertilizer markedly increased C16 mineralization. Highly active cold-adapted hydrocarbon-degrading consortia were prepared from soil slurries, and their degradative potentials were monitored by biomass measurements and mineralization activity. Bio augmentation of the contaminated soils with consortia containing the greatest percentages of degradative bacteria resulted in the shortest C16 mineralization acclimation period. However, treatment with the consortia plus fertilizer did not appreciably increase C16 mineralization or reduce total petroleum hydrocarbon concentrations to a greater extent than did the fertilizer treatment alone. These results indicate that the soils possessed sufficient numbers of cold-adapted degradative bacteria, and that fertilizer application alone was sufficient to obtain elevated levels of degradative activity at low ambient summer temperatures. 相似文献
59.
A combination of allozyme and mitochondrial DNA markers were used to determine the contribution of recent and ancient causes
of patterns of genetic variation within and among 46 populations of the endangered golden sun moth, Synemon plana. Allozyme analysis grouped the 46 populations into 5 major genetic clusters that corresponded closely with geographic location
following a classic isolation-by-distance model. Phylogenetic analysis of 14 mtDNA haplotypes revealed two reciprocally monophyletic
groups. One of these groups (containing 4 geographically distant populations) was clearly identified by allozyme analysis
and represents a distinct evolutionary unit. The remaining 4 allozyme groups were not distinguishable by mtDNA analysis. The
evidence suggests that the populations within these groups derived from a small founding population that underwent rapid demographic
expansion in ancient times. This was followed by more recent population bottlenecks resulting from habitat fragmentation associated
with the widespread introduction of agriculture into the region. The generally low levels of allozyme and nucleotide diversity
within these populations support this hypothesis.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
60.
Ana Whyte Luis V. Monteagudo Angel Díaz-Otero M. Eugenia Lebrero M. Teresa Tejedor M. Victoria Falceto Jaime Whyte Margarita Gallego 《Animal reproduction science》2009,115(1-4):328-333
Persistence of the Müllerian duct syndrome (PMDS) is a rare form of pseudohermaphroditism characterized by the presence of uterus and oviducts in otherwise normally differentiated SRY-positive 78 XY canine males. Undescended testicles are also common. We report a case of a male PMDS dog with a uterus and bilateral cryptorchidism. The dog had an incomplete regression of the mesonephric tubules. As a consequence of this an abnormally enlarged head of the epididymis was observed. In addition, an extreme reduction in size of both the body and the tail was found. Microscopic examination of both testicles revealed bilateral hyperplasia of Leydig cells. The progesterone blood level was measured by ELISA and was found to be abnormally high (3.18 ng/ml) compared to that of normal male dogs (lower than 1 ng/ml). Three months after surgical removal of the internal genitalia, the serum progesterone, testosterone and oestradiol levels were normal for a castrated male dog. 相似文献