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71.
The effects of glutamate on the in vitro basal steroid production of three maturational stages of rainbow trout (Oncorhynchus mykiss) ovarian follicles were investigated. Radioimmunoassays were used to measure the rates of synthesis of testosterone (T) and 17-estradiol (E2). High performance liquid chromatography (HPLC) was used to examine the steroid metabolites produced from a tritium labeled precursor, pregnenolone (P5). The glutamate agonist, N-methyl-d,l-aspartate (NMA) had a dose-dependent suppressive effect on T and E2 synthesis in mid-vitellogenic (MV) follicles, but had no significant effect on early- (EV) and late-vitellogenic (LV) follicles. l-glutamic acid (GA) had a dose-related suppressive effect on T synthesis by MV follicles, suppressing both T and E2 synthesis by LV follicles, but having no effect on EV follicles. HPLC separation of the steroid metabolites synthesized from P5 showed clear evidence of differences in rates of overall steroidogenesis of the three follicular stages, but no effect of either NMA or GA on the nature or the amount of the metabolites produced by the three developmental stages examined. The findings suggest that glutamate may act via a reduction in the production of P5, which is the principal rate-limiting step in the steroidogenic cascade, and not via modulation of steroidogenic enzyme activities.  相似文献   
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73.
Habitat selection by chironomid larvae: fast growth requires fast food   总被引:2,自引:0,他引:2  
1. Sediments have been considered as a habitat, a cover from predators and a source of food, but also as a source of potential toxic compounds. Therefore, the choice of a suitable substrate is essential for the development of chironomids. 2. For the midge Chironomus riparius (Meigen 1804) the growth rate of larvae has often been related to the food quality in sediments rather than to the amount of toxicants in the sediment. Both food quality and sediment-bound toxicants have been reported to determine the field distribution of chironomid larvae. 3. We therefore studied the habitat selection by C. riparius larvae of floodplain lake sediments, differing in both food quality and concentrations of sediment-bound toxicants. We offered the different sediments pairwise to the chironomid larvae in a choice experiment and their settlement in the paired sediments was determined after 10 days. 4. It was observed that larvae showed a clear preference for sediments with higher food quality, which also provided better growth conditions, and that the food quality overruled avoidance of the sediments with higher toxicant concentrations. 5. Our observations correspond with the persistence of this fast growing opportunistic chironomid species in organically enriched aquatic ecosystems independent of the contamination level.  相似文献   
74.

Background  

Host parasitism by Trichomonas vaginalis is complex. Adherence to vaginal epithelial cells (VECs) is mediated by surface proteins. We showed before that antisense down-regulation of expression of adhesin AP65 decreased amounts of protein, which lowered levels of T. vaginalis adherence to VECs. We now perform antisense down-regulation of expression of the ap33 gene to evaluate and confirm a role for AP33 in adherence by T. vaginalis. We also used an established transfection system for heterologous expression of AP33 in T. foetus as an additional confirmatory approach.  相似文献   
75.

Background

Most patients with metastatic non-small cell lung cancer (NSCLC) will face treatment with systemic therapy. Current clinical studies are demonstrating improvements in chemotherapy and overall survival. However, it remains unclear whether these results are translated into clinical practice.

Methods

We reviewed all stage IV NSCLC patients without second malignancies that were diagnosed from 2004 to 2006 at our institution. 493 consecutive patients were included into this retrospective analysis and were followed-up until end of 2011.

Results

352 patients (71.4%) received systemic therapy for up to 7 lines. For most patients, adjustments of dosages or applications had to be made at some point of the treatment, but the total applied dose remained generally close to the intended dose. The best disease control (BDC) rate decreased with increasing therapy lines from 59.7% to about 35%. Patients with palliative local therapy but no systemic treatment demonstrated inferior survival (median 2.9 versus 8.7 months, p < 0.001). The median interval between last treatment and death was 50 days and 15 days for chemotherapy and anti-EGFR therapy, respectively. BDC to the previous therapy lines was predictive for improved BDC to third- but not second-line therapy. Performing multivariate analysis, BDC to previous therapy, never-/ former-smoking status, and age > 70 years were associated with improved survival performing third-line therapy.

Conclusions

Stage IV NSCLC patients may receive substantial systemic therapy resulting in response and median survival rates that are comparable to data from clinical studies. However, preselection factors are increasingly important to improve therapy outcome and life quality.  相似文献   
76.
Individual male three-spined sticklebacks in the field, often collected eggs for longer (up to 10 days) than had been reported for sticklebacks in captivity (3–6 days). The probability that a male stopped collecting eggs increased with the number of eggs already present, and possibly with the age of the eggs. Males with nests hidden under a plant were more likely to continue collecting than males with exposed nests. These results are discussed in the light of theoretical considerations that predict when males should stop collecting further eggs.  相似文献   
77.
78.

Aims

Mid- and long-term safety and efficacy of the Absorb bioresorbable vascular scaffold (BVS) have been studied in randomised trials; however, most were not individually powered for clinical endpoints. We performed a weighted meta-analysis comparing mid- and long-term outcomes in patients treated with the BVS compared with the Xience metallic stent.

Methods and results

Randomised trials comparing the BVS and Xience were identified by searching MEDLINE, EMBASE and conference abstracts. Seven trials were included (BVS n = 3258, Xience n = 2319) with follow-up between 1–3 years. The primary outcome of target lesion failure occurred more frequently in BVS compared with Xience [OR 1.34; 95% CI 1.11–1.62, p = 0.003]. Overall definite or probable device thrombosis occurred more frequently with the BVS [OR 2.86; 95% CI 1.88–4.36, p < 0.001] and this extended beyond 1 year of follow-up [OR 4.13; 95% CI 1.99–8.57, p < 0.001]. Clinically indicated or ischaemia driven target lesion revascularisation [OR 1.43; 95% CI 1.11–1.83, p = 0.005] and myocardial infarction (all MI) [OR 1.64; 95% CI 1.20–2.23, p = 0.002] were more frequently seen in the BVS compared with Xience. Rates of target vessel failure [OR 1.15; 95% CI 0.91–1.46, p = 0.25] and cardiac death [OR 0.91; 95% CI 0.57–1.46, p = 0.71] were not significantly different between BVS and Xience.

Conclusion

This meta-analysis shows a higher rate of target lesion failure and an almost threefold higher rate of device thrombosis in BVS compared with Xience, which extends beyond the first year. Device thrombosis did not lead to an overall increased (cardiac) mortality.
  相似文献   
79.
80.
Bardet-Biedl syndrome (BBS) is a rare, primarily autosomal-recessive ciliopathy. The phenotype of this pleiotropic disease includes retinitis pigmentosa, postaxial polydactyly, truncal obesity, learning disabilities, hypogonadism and renal anomalies, among others. To date, mutations in 15 genes (BBS1-BBS14, SDCCAG8) have been described to cause BBS. The broad genetic locus heterogeneity renders mutation screening time-consuming and expensive. We applied a strategy of DNA pooling and subsequent massively parallel resequencing (MPR) to screen individuals affected with BBS from 105 families for mutations in 12 known BBS genes. DNA was pooled in 5 pools of 21 individuals each. All 132 coding exons of BBS1-BBS12 were amplified by conventional PCR. Subsequent MPR was performed on an Illumina Genome Analyzer II? platform. Following mutation identification, the mutation carrier was assigned by CEL I endonuclease heteroduplex screening and confirmed by Sanger sequencing. In 29 out of 105 individuals (28%), both mutated alleles were identified in 10 different BBS genes. A total of 35 different disease-causing mutations were confirmed, of which 18 mutations were novel. In 12 additional families, a total of 12 different single heterozygous changes of uncertain pathogenicity were found. Thus, DNA pooling combined with MPR offers a valuable strategy for mutation analysis of large patient cohorts, especially in genetically heterogeneous diseases such as BBS.  相似文献   
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