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1.
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   
2.
Abstract Broad host-range RK2-based cosmid vectors ('costramids') are increasingly used in molecular genetic studies of Gram-negative soil bacteria such as Rhizobium spp. we describe a simple modification of existing methods, whereby a genomic library constructed in a stringently replicated vector can be screened for genes which are undetectable by colony hybridization due to background cross-hybridization. This method allows the use of 'heterologous' probes (interspecies hybridization) to isolate several presumptive genes of interest from a gene bank of Rhizobium sp. NGR234 made in the costramid pRK7813. These are a gene with homology to the citrate synthase gene ( gltA ) or Escherichia coli , the gene encoding δ-aminol evulinic acid synthase ( hemA ), and a gene or genes regulating dicarboxylate transport.  相似文献   
3.
Transgender women are particularly at risk of HIV infection, but little evidence exists on effective HIV prevention strategies with this population. We evaluated whether Sisters, a peer-led program for transgender women, could reduce HIV risks in Pattaya, Thailand. The study used time-location sampling to recruit 308 transgender women in Pattaya into a behavioral survey in 2011. Coarsened exact matching was used to create statistically equivalent groups of program participants and non-participants, based on factors influencing likelihood of program participation. Using multivariable logistic regression, we estimated effects of any program participation and participation by delivery channel on: condom use at last sex; consistent condom and condom/water-based lubricant use in the past 3 months with commercial, casual, and regular partners; and receipt of HIV testing in the past 6 months. Program coverage reached 75% of the population. In a matched sub-sample (n = 238), participation in outreach was associated with consistent condom/water-based lubricant use with commercial partners (AOR 3.22, 95% CI 1.64–6.31). Attendance at the Sisters drop-in center was associated with receiving an HIV test (AOR 2.58, 95% CI 1.47–4.52). Dedicated transgender-friendly programs are effective at reducing HIV risks and require expansion to better serve this key population and improve HIV prevention strategies.  相似文献   
4.
Summary Rhizobium sp. NGR234 in a fast-growing Rhizobium strain with a broad host range. The location and role of chromosomal genes involved in cellular metabolism or in the legume symbioses is unknown. We isolated a series of auxotrophic and antibiotic resistant mutants of NGR234 and utilized a chromosome mobilization system based on Tn5-Mob and pJB3JI; Tn5-Mob donor strains behaved like Hfr strains, transferring the chromosome polarly at high frequency from a fixed point of insertion. The use of four different strains with Tn5-Mob located at different nutritional loci in crosses with double auxotrophic recipients, allowed us to build up a circular linkage map of NGR234 based on relative recombination frequencies. Also, symbiotically important genes identified by site-directed mutagenesis, such as hemA and ntrA, could be located and mapped on the chromosome.Abbreviations Tc tetracycline - Sp spectinomycin - Rif rifampicin - Km kanamycin  相似文献   
5.
Summary The clonedntrA (rpoN) gene andntrA mutants ofRhizobium meliloti were used to isolate the homologous gene from the broad-host rangeRhizobium sp. NGR234 by hybridization and interspecies complementation. The NGR234 locus was analyzed by deletion and insertional mutagenesis. A site-directedntrA mutant, NGR234rn1, was made with an interposon, GmI, and its phenotype was examined ex planta and in symbiosis. NGR234rn1 formed Fix nodules on six genera tested from among its legume hosts, including both indeterminate and determinate nodule-type plants. Formation of nodules onMacroptilium was delayed, and expression of anR. meliloti nodABC-lacZ fusion was reduced by the mutant allele.  相似文献   
6.
Summary The hemA gene which encodes -aminolaevulinic acid synthase (ALAS), was cloned and characterized from the broad host-range Rhizobium strain NGR234. A cosmid, identified by hybridization with the cloned gene of R. meliloti and complementation of an R. meliloti hemA mutant, was subcloned to yield a 5.5 kb fragment containing the entire NGR234 gene. A physical-genetic map was made and the interposon was introduced into a single EcoRI site which bisects the gene. The mutated gene was homogenotized into NGR234 to generate a hemA mutant, with a view to evaluating the role of rhizobial bacteroid ALAS activity for a wide variety of legume symbioses. The mutant strain formed an ineffective (Fix) symbiosis with all tested host plants. These included tropical legumes that produce either indeterminate (Leucaena) or determinate (Desmodium, Macroptilium, Lablab, Vigna) root nodules.Abbreviations ALA -aminolaevulinic acid - ALAS aminolaevulinic acid synthase - Lb leghaemoglobin - Lb-haem haem moiety of leghaemoglobin  相似文献   
7.
Demonstration of two protein kinases in extracts of Legionella micdadei   总被引:9,自引:0,他引:9  
Protein kinases I (PK I) and II (PK II) were purified 253- and 13.5-fold, respectively, from an extract of sonically disrupted cells of Legionella micdadei by ion-exchange chromatography on QAE-Sephadex, by histone affinity chromatography, and by HPLC-gel filtration chromatography. Both enzymes catalysed the phosphorylation of calf thymus histones, with a Km of 2.7 mg ml-1 for PK I and 2.9 mg ml-1 for PK II. Histone H2b was the best protein kinase substrate for both PK I and PK II. The pH optima were 6.8 and 7.0 for PK I and PK II respectively. The Km for ATP was 0.29 mM for PK I and 0.33 mM for PK II. PK II activity was stimulated by either cAMP or cGMP, whereas PK I was inhibited by both cyclic nucleotides. The activity of PK I was unaffected by addition of calmodulin, diacylglycerol and mixtures of Ca2+ and acidic phospholipids, but these additions increased PK II activity threefold. The activity of PK II was stimulated by spermine and spermidine, but PK I was inhibited by these compounds. PK I and PK II were both strongly inhibited by heparin.  相似文献   
8.
Using [U-14C]phosphatidylinositol as substrate, Ca2+-dependent phospholipase C activity was detected in a group of bovine adrenal medullary proteins that bind to chromaffin granule membranes in the presence of Ca2+ ("chromobindins," Creutz, C. E., Dowling, L. G., Sando, J. J., Villar-Palasi, C., Whipple, J. H., and Zaks, W. J. (1983) J. Biol. Chem. 258, 14664-14674). The activity was maximal at neutral pH and represented an 80- to 240-fold enrichment of adrenal medullary cytosol phospholipase C activity measured at pH 7.3. The stimulation of activity by Ca2+ was complex; no activity was present in the absence of Ca2+, 25% activation occurred at 1 microM Ca2+, and full activation at 5 mM Ca2+. The enzyme bound to chromaffin granule membranes in the presence of 2 mM Ca2+ but was released at 40 microM Ca2+, suggesting that intrinsic enzyme activity may be regulated by [Ca2+] at 1 microM, but additional activation at higher concentrations of Ca2+ is seen in vitro as a result of Ca2+-dependent binding of the active enzyme to substrate-containing membranes. This enzyme may generate diacylglycerol and phosphorylated inositol to act as intracellular messengers in the vicinity of the chromaffin granule membrane during the process of exocytosis.  相似文献   
9.
Horizontal starch gel electrophoresis was used to estimate the amount of genetic divergence between Notropis cornutus and N. chrysocephalus. Measures of genetic identity (1) and distance (D) were 0.881 and 0.127 ± 0.055 (s.e.), respectively. These estimates correspond more closely to the sibling species status of these taxa than other previously reported estimates. Notropis cornutus was found to be significantly more variable than N. chrysocephalus electrophoretically and morphologically. Assuming the existence of an electrophoretic clock, the time of divergence was calculated to be roughly 1.9–2.5 million years. This estimate corresponds very closely to a previously hypothesized late Pliocene divergence.  相似文献   
10.
To test the value of oncofetal antigens in the cytologic diagnosis of effusions, immunoperoxidase staining with antisera to carcinoembryonic antigen (CEA), alpha fetoprotein (AFP), pregnancy-specific beta 1-glycoprotein (SP1) and placental alkaline phosphatase (PLAP) was carried out on pleural and peritoneal fluids from 72 cases. Sections of formalin-fixed, paraffin-embedded cell blocks were used in most cases; cytocentrifuge preparations were used in some. Reactions were negative with all antisera in 23 of 24 nonmalignant effusions as well as in all 7 cases of malignant mesothelioma and 4 cases of malignant lymphoma. In 24 of 36 confirmed carcinomatous effusions, staining was positive with one or more antisera, including anti-CEA positivity in 23 of the 24 cases. In 5 of the 24 cases with positive staining, a confident diagnosis of malignancy had not been made on routine cytologic preparations. Immunoperoxidase staining for CEA appears to be of supportive value in the cytologic diagnosis of malignancy in effusions.  相似文献   
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