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991.
992.
OBJECTIVES: Premenopausal women have a lower incidence of cardiovascular disease than men, but this female advantage disappears after menopause, suggesting that female sex hormones exert some cardioprotective effects. One of the mechanisms proposed to explain this cardioprotection is the antioxidant properties of estrogens. The aim of this work was to assess whether fluctuations in ovarian hormones, particularly 17beta-estradiol (E(2)), during the menstrual cycle were associated with changes in the low-density lipoprotein (LDL) particle size, fatty acyl composition, alpha-tocopherol content and in vitro oxidizability. METHODS: Twenty-eight healthy premenopausal women (mean age: 32.2 years) participated in the study. Blood was drawn on days 3 (menstrual phase), 14 (follicular phase) and 22 (luteal phase) of the menstrual cycle for plasma determinations and LDL isolation. Plasma E(2), progesterone, follicle-stimulating hormone and luteinizing hormone were determined by immunoassay. LDL oxidation by Cu(2+)- and 2,2'-azobis (2-amidinopropane) was measured by the formation of conjugated dienes, LDL particle size by quasi-elastic light scattering, fatty acyl composition by gas chromatography, alpha-tocopherol by reversed phase HPLC. A within-subjects analysis of variance was performed to determine significant differences of the variables over the course of a subject's menstrual cycle. RESULTS: The LDL oxidizability indices (lag time before the onset of propagation and the maximal oxidation rate) did not change during the menstrual cycle. The LDL particle size (24.8+/-1.7 nm diameter), alpha-tocopherol (11.7+/-3.7 nmol/mg LDL protein) and fatty acyl composition also remained constant. CONCLUSIONS: The LDL physicochemical properties and oxidizability are not affected by menstrual cycle phase.  相似文献   
993.
An integrated readout computed radiography system (Fuji XU-D1) incorporating dual-side imaging plates (ST-55BD) was analyzed in terms of modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) for standard beam qualities RQA 9 and RQA 5. NPS and DQE were assessed using a detector entrance air kerma consistent with clinical practice for chest radiography. Similar investigation was performed on a standard reader (Fuji FCR 5000) using single-side imaging plates (ST-VI). Negligible differences were found between the MTFs of the two imaging systems for RQA 9, whereas for RQA 5 the single-side system exhibited slightly superior MTF. Regarding noise response, the dual-side system turned out to be better performing for both beam qualities over a wide range of frequencies. For RQA 9, at 8 microGy, the DQE of the dual-side system was moderately higher over the whole frequency range, whereas for RQA 5, at 10 microGy, significant improvement was found at low- and midrange frequencies. As an example, at 1 cycle/mm, the following improvements in the DQE of the dual-side system were observed: +22% (RQA 9, at 8 microGy), +50% (RQA 9, at 30 microGy), and +45% (RQA 5, at 10 microGy).  相似文献   
994.
The prevalence of food allergy: a meta-analysis   总被引:7,自引:2,他引:5  
BACKGROUND: There is uncertainty about the prevalence of food allergy in communities. OBJECTIVE: To assess the prevalence of food allergy by performing a meta-analysis according to the method of assessment used. METHODS: The foods assessed were cow's milk, hen's egg, peanut, fish, shellfish, and an overall estimate of food allergy. We summarized the information in 5 categories: self-reported symptoms, specific IgE positive, specific skin prick test positive, symptoms combined with sensitization, and food challenge studies. We systematically searched MEDLINE and EMBASE for publications since 1990. The meta-analysis included only original studies. They were stratified by age groups: infant/preschool, school children, and adults. RESULTS: A total of 934 articles were identified, but only 51 were considered appropriate for inclusion. The prevalence of self-reported food allergy was very high compared with objective measures. There was marked heterogeneity between studies regardless of type of assessment or food item considered, and in most analyses this persisted after age stratification. Self-reported prevalence of food allergy varied from 1.2% to 17% for milk, 0.2% to 7% for egg, 0% to 2% for peanuts and fish, 0% to 10% for shellfish, and 3% to 35% for any food. CONCLUSION: There is a marked heterogeneity in the prevalence of food allergy that could be a result of differences in study design or methodology, or differences between populations. CLINICAL IMPLICATIONS: We recommend that measurements be made by using standardized methods, if possible food challenge. We need to be cautious in estimates of prevalence based only on self-reported food allergy.  相似文献   
995.
This study evaluates the prognostic significance of p53 and p63 immunolocalisation in oral squamous cell carcinoma samples from 45 matched primary tumors (PT) and lymph node metastases (LNM). Data regarding patient age, gender, primary site, histological differentiation, metastasis, disease-free survival (DFS) and overall survival (OS) were available. p53 and p63 immunolabeling was detected in 17 (37.8%) and 23 (51.1%) of the PT, respectively. For LNM, there was p53 and p63 labeling in 23 (51.1%) and 26 (57.8%) cases, respectively. Most cases showed similar labeling in PT and the corresponding LNM (73.3% for p53 and 53.3% for p63, respectively). No statistically significant associations were found between p53 and p63 immunolabeling and histological differentiation; p63 positive tumors showed higher DFS (p=0.006) and OS (p=0.049); and p53-negative tumors had a higher DFS interval (p=0.009). Our findings suggest that initially p53-negative tumors and initially p63-positive tumors that retain this labeling pattern may follow less aggressive biological courses and present better prognoses.  相似文献   
996.
997.
Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of both dengue and yellow fever. Use of insecticides is one of the primary ways to control this medically important insect pest. However, few new insecticides have been developed for mosquito control in recent years. As a part of our collaborative effort to search for new insecticides to control mosquitoes, piperidine was used as base compound for further optimization. Herein, we report the structure-activity relationships of 33 piperidines against adult female Ae. aegypti. On the basis of 24-h LD50 values after topical application, the most toxic compound was 2-ethyl-piperidine, with an LD50 as low as 0.8 microg per mosquito. The toxicities of piperidine derivatives were significantly decreased when a benzyl moiety was attached to the carbon of the piperidine ring, with an LD50 value as high as 29.2 microg per mosquito. The toxicity order of three moieties attached to the carbon of the piperidine ring was ethyl- > methyl- > benzyl-derivatives. When the same moiety was attached to the piperidine ring, the carbon position to which the moiety was attached conferred different toxicity and the toxicity order was second carbon > third carbon > fourth carbon. Together, these preliminary results may be useful in guiding further piperidine ring modifications in the development of potential new insecticides.  相似文献   
998.
Dysfunction of the host immune system in cancer patients can be due to a number of factors, including suppression of tumor-associated antigen reactive lymphocytes by CD4(+)CD25(+) regulatory T (Treg) cells. Several studies suggest that Tregs are elevated in cancer patients and that depletion of Tregs may enhance the antitumor immunity of host, but the pathogenic and mechanistic relationship between cancer and Tregs is still unclear. In this report, we show that Tregs are increased in peripheral blood mononuclear cells (PBMCs) from hepatocellular carcinoma (HCC) patients and positively correlate with tumor burden. When PBMCs are co-cultured with human hepatoma cell lines Huh7, HepG2, and Hclone5, CD4(+)CD25(+)-T cell populations increase in frequency and undergo phenotypic and functional changes. CD45RA, CD45RO, CD69, CD62L, GITR, CTLA-4, Ki67, granzyme A, granzyme B, and FOXP3 expression were upregulated in CD4(+)CD25(+) cells after in vitro exposure to HCC cell lines. CD4(+)CD25(+) T cells from PBMCs that were co-cultured with Huh7 cells also have higher suppressor ability compared to that of the CD4(+)CD25(+) T cells from control PBMC. Huh7 culture supernatants appear to promote CD4(+)CD25(+) T-cell proliferation and inhibit CD4(+)CD25(-) T-cell proliferation. In conclusion, these results strongly suggest that tumor-related factors not only induce and expand CD4(+)CD25(+) cells, but also enhance their suppressor ability.  相似文献   
999.
1000.
Type I IFN are cytokines which play a central role in host resistance to viral or microbial infections and are important components linking innate and adaptive immunity. We and others have previously demonstrated that the production of IFN-beta by DC following bacterial infections or TLR triggering influences, in an autocrine manner, their maturation. In this study, we investigated whether IFN-beta release modulates the phenotype of the immature DC and their response to a subsequent TLR stimulation. The induction of CD86, HLA-DR, CD38 and B7H1 and the absence of CCR7 and CD83 expression upon IFN-beta treatment suggest that IFN-beta-primed DC remain at the site of infection acquiring an activated phenotype. These results prompted us to investigate the response of IFN-beta-primed DC to TLR stimulation. While IFN-beta pretreatment increases slightly the expression of maturation markers in TLR2- or TLR4-stimulated DC, it is able to modulate selectively the secretion of inflammatory and immuno-regulating cytokines. Interestingly, IL-27p28 subunit was induced by IFN-beta alone or during LPS-induced maturation of DC in a type I IFN-dependent manner through IFN regulatory factor-1 (IRF-1) activation. Taken together, our results shed light on the capacity of IFN-beta to finely tune DC response to invading pathogens.  相似文献   
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