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D B Snead A Weltman J Y Weltman W S Evans J D Veldhuis M M Varma C D Teates E A Dowling A D Rogol 《Journal of applied physiology》1992,72(6):2149-2156
We examined the relationships among reproductive hormone concentrations and bone mineral density (BMD) in 43 women runners classified as eumenorrheic (n = 24), oligomenorrheic (n = 8), or amenorrheic (n = 11). Results were compared with a eumenorrheic nonrunner control group (n = 11). Serum 17 beta-estradiol, progesterone, and dehydroepiandrosterone sulfate concentrations were determined in daily blood samples for 21 days, and integrated concentrations (areas under the curve) were calculated. BMD was assessed at the lumbar spine and proximal femur by dual-photon absorptiometry. As expected, 17 beta-estradiol, progesterone, and lumbar spine BMD were higher in the control and eumenorrheic runner groups than in the oligomenorrheic and amenorrheic runner groups (P less than 0.05). Progesterone concentration was significantly correlated with lumbar spine BMD in the eumenorrheic runners (r = 0.61). None of the steroid hormones was significantly related to BMD in the oligomenorrheic/amenorrheic group. The present data suggest that circulating levels of gonadal steroid hormones affect axial BMD in eumenorrheic runners. 相似文献
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Summary Studies on the effect of different levels of sucrose in the slurry of peat-based Rhizobium inoculant on germination, seedling growth, and rhizosphere fungi of peanut and soybean revealed that the limits of tolerance for good germination were 2.5 and 5 per cent of the sugar, respectively. Fusaria and aspergilli were invariably present at all levels of sucrose whereas species of Penicillium, Myrothecium, Cunninghamella and Curvularia were isolated only from the rhizosphere at higher levels of the sugar 相似文献
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Goats and some sheep synthesize a juvenile hemoglobin, Hb C (alpha 2 beta
C2), at birth and produce this hemoglobin exclusively during severe anemia.
Sheep that synthesize this juvenile hemoglobin are of the A haplotype.
Other sheep, belonging to a separate group, the B haplotype, do not
synthesize hemoglobin C and during anemia continue to produce their adult
hemoglobin. To understand the basis for this difference we have determined
the structural organization of the beta- globin locus of B-type sheep by
constructing and isolating overlapping genomic clones. These clones have
allowed us to establish the linkage map 5' epsilon I-epsilon II-psi beta
I-beta B-epsilon III-epsilon IV- psi beta II-beta F3' in this haplotype.
Thus, B sheep lack four genes, including the BC gene, and have only eight
genes, compared with the 12 found in the goat globin locus. The goat
beta-globin locus is as follows: 5' epsilon I-epsilon II-psi beta X-beta
C-epsilon III-epsilon IV-psi beta Z-beta A-epsilon V-epsilon VI-psi beta
Y-beta F3'. Southern blot analysis of A-type sheep reveals that these
animals have a beta- globin locus similar to that of goat, i.e., 12 globin
genes. Thus, the beta-globin locus of B-haplotype sheep resembles that of
cows and may have retained the duplicated locus of the ancestor of cows and
sheep. Alternatively, the B-sheep locus arrangement may be the result of a
deletion of a four-gene set from the triplicated locus.
相似文献
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When incubated in high galactose media, fibroblasts from individuals with the severe (Mediterranean) variety of glucose-6-phosphate dehydrogenase (G6PD) deficiency accumulate significantly less galactitol than do fibroblasts from matched control subjects. The effect is not observed in fibroblasts from black subjects with the more common, and milder, A- variant of G6PD deficiency. Since aldose reductase and sorbitol dehydrogenase activities in experimental and control fibroblasts are identical, the effect is most likely due to the substantial reduction in NADPH levels in severely G6PD-deficient cells. Sorbitol does not accumulate either in control or in G6PD deficient fibroblasts incubated in high glucose medium, most likely because of the action of sorbitol dehydrogenase, and the presence of a carrier-mediated glucose transport system in the cell membrane which limits the concentration of glucose that can accumulate in these cells. 相似文献
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Rajendra Varma Ranbir S. Varma Williams S. Allen Ahmad H. Wardi 《Biochimica et Biophysica Acta (BBA)/General Subjects》1974,362(3):584-588
Fractional molar ratios of serine, threonine and aspartic acid to neutral sugars in the purified bovine vitreous humor hyaluronate, and a 4–5-fold increase in the percentage of these amino acids and the absence of sugar alditols in hyaluronate reduced with NaBH4---PdCl2 after alkali treatment indicated the absence of a carbohydrate—protein linkage. Gel filtration behavior, a decrease in intrinsic viscosity of reduced hyaluronate to about one-half and a significant decrease in its specific rotation suggested that the two antiparallel chains of the hyaluronate double helix may come apart upo reduction. The vitreous humor hyaluronate contained 109.2 ppm of “bound” silicon. It is suggested that the bound silicon may bridge the two antiparallel chains through the neutral sugars and/or through the hydroxyl group of the uronic acid moiety. 相似文献
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