首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   66篇
  免费   8篇
基础医学   18篇
临床医学   15篇
内科学   20篇
神经病学   14篇
外科学   2篇
预防医学   2篇
药学   2篇
中国医学   1篇
  2023年   1篇
  2021年   3篇
  2018年   2篇
  2017年   1篇
  2016年   1篇
  2014年   4篇
  2013年   4篇
  2012年   4篇
  2011年   4篇
  2010年   2篇
  2009年   1篇
  2008年   6篇
  2007年   8篇
  2006年   9篇
  2005年   4篇
  2004年   5篇
  2003年   9篇
  2002年   4篇
  2000年   1篇
  1998年   1篇
排序方式: 共有74条查询结果,搜索用时 31 毫秒
1.
BackgroundMicrobial contamination of human skin allografts is a frequent cause of allograft discard. Our purpose was to evaluate the discard rate of skin bank contaminated allografts and specific procedures used to reduce allograft contamination without affecting safety.MethodsWe conducted at the Lille Tissue Bank a retrospective study of all deceased donors (n = 104) harvested from January 2018 to December 2018. Skin procurement was split into 3 zones: the back of the body and the two legs that were processed separately. It represented 433 cryopreserved skin allograft pouches of approximatively 500 cm² each. Donors were almost equally split between brain-dead (53%, 55/104) and cadaveric (47%, 49/104) donors.ResultsOut of all donors, 42 (40.5%) had at least one sampling zone with a positive microbiological test resulting in 106 (24%) contaminated skin pouches. The contamination rate did not vary according to the harvested zone or type of donor. Traumatic deaths showed significantly less contamination rates than other death types (p < 0.05). Contamination rate decreased with time spent in the antibiotic solution. The risk of having contaminated allografts was five-fold higher when the skin spent less than 96 h in the antibiotic cocktail (p < 0.05). According to our validation protocol, most donors (32/42, 76%) had skin allografts contaminated with bacteria (mainly Staphylococcus spp) compatible with clinical use. No recipient infection was recorded as a result of skin graft contaminated with saprophytic or non-pathogenic germs. By harvesting 3 separate zones per donor, the total surface area for clinical use increased by 53% for contaminated donors. Overall, the proportion of contamination-related discarded allografts was 3.2% (14/433 of pouches).ConclusionFew simple pragmatic measures (including skin incubation in the antibiotic bath for at least 96 h at 4 °C, splitting the skin harvesting areas to minimize the risk of cross-infection and clinical use of allografts contaminated with saprophytic and non-pathogenic germs) can reduce the discard rate of contaminated allografts without affecting clinical safety.  相似文献   
2.
3.
Perinatal hypoxia is a cause of cerebral injury in foetuses and neonates. Detection of foetal hypoxia during labour based on the pattern recognition of heart rate signals suffers from high observer variability and low specificity. We describe a new automated hypoxia detection method using time–frequency analysis of heart rate variability (HRV) signals. This approach uses features extracted from the instantaneous frequency and instantaneous amplitude of HRV signal components as well as features based on matrix decomposition of the signals’ time–frequency distributions using singular value decomposition and non-negative matrix factorization. The classification between hypoxia and non-hypoxia data is performed using a support vector machine classifier. The proposed method is tested on a dataset obtained from a newborn piglet model with a controlled hypoxic insult. The chosen HRV features show strong performance compared to conventional spectral features and other existing methods of hypoxia detection with a sensitivity 93.3 %, specificity 98.3 % and accuracy 95.8 %. The high predictive value of this approach to detecting hypoxia is a substantial step towards developing a more accurate and reliable hypoxia detection method for use in human foetal monitoring.  相似文献   
4.
5.
The structural changes of diblock‐copolymer micelles under pressures from 200 to 16 000 psi are investigated using small‐angle neutron scattering (SANS). Asymmetric polystyrene‐block‐polyisoprene (PS–PI) diblock copolymers are dissolved in decane, a selective solvent for PI, to form spherical micelles with a core of PS and a corona of PI. The micellar solutions are put under pressure at temperatures of 25 to 60 °C. At room temperature, elevating the pressure from 200 to 16 000 psi has no effect on the size of the micelles. While the micellar solutions remain stable, instantaneous association of micelles is detected. In contrast to micelles at atmospheric pressure, increasing the temperature at elevated pressures does not lead to dissociation of micelles; instead, the micelles aggregate and evolve into sheet‐like structures, reminiscent of a macroscopic phase separation. Furthermore, higher pressures lead to a smaller temperature range in which shape transitions take place.

  相似文献   

6.

Background

The intestinal microbiota plays a crucial role in the maintenance of gut homeostasis. Changes in crosstalk between the intestinal epithelial cells, immune cells and the microbiota are critically involved in the development of inflammatory bowel disease. In the experimental mouse model, the development of colitis induced by dextran sulfate sodium (DSS) promotes overgrowth of the opportunistic yeast pathogen Candida glabrata. Conversely, fungal colonization aggravates inflammatory parameters. In the present study, we explored the effect of C. glabrata colonization on the diversity of the gut microbiota in a DSS-induced colitis model, and determined the impact of soluble β-glucans on C. glabrata-host interactions.

Results

Mice were administered a single inoculum of C. glabrata and were exposed to DSS treatment for 2 weeks in order to induce acute colitis. For β-glucan treatment, mice were administered with soluble β-glucans purified from C. glabrata (3?mg per mouse), orally and daily, for 5 days, starting on day 1. The number of C. glabrata colonies and changes in microbiota diversity were assessed in freshly collected stool samples from each tagged mouse, using traditional culture methods based on agar plates. An increase in Escherichia coli and Enterococcus faecalis populations and a reduction in Lactobacillus johnsonii and Bacteroides thetaiotaomicron were observed during colitis development. This decrease in L. johnsonii was significantly accentuated by C. glabrata overgrowth. Oral administration of β-glucans to mice decreased the overgrowth of aerobic bacteria and IL-1β expression while L. johnsonii and B. thetaiotaomicron populations increased significantly. β-glucan treatment increased IL-10 production via PPARγ sensing, promoting the attenuation of colitis and C. glabrata elimination.

Conclusions

This study shows that the colonic inflammation alters the microbial balance, while β-glucan treatment increases the anaerobic bacteria and promotes colitis attenuation and C. glabrata elimination.
  相似文献   
7.
8.
Screening of the antifungal activities of ten Guadeloupean plants was undertaken to find new extracts and formulations against superficial mycoses such as onychomycosis, athlete's foot, Pityriasis versicolor, as well as the deep fungal infection Pneumocystis pneumonia. For the first time, the CMI of these plant extracts [cyclohexane, ethanol and ethanol/water (1:1, v/v)] was determined against five dermatophytes, five Candida species, Scytalidium dimidiatum, a Malassezia sp. strain and Pneumocystis carinii. Cytotoxicity tests of the most active extracts were also performed on an HaCat keratinocyte cell line. Results suggest that the extracts of Bursera simaruba, Cedrela odorata, Enterolobium cyclocarpum and Pluchea carolinensis have interesting activities and could be good candidates for developing antifungal formulations. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
9.
OBJECTIVES: Anti- S. cerevisiae mannan antibodies (ASCA) are human antibodies associated with Crohn's disease (CD) reacting with Saccharomyces cerevisiae ( S. cerevisiae ) mannan polymer. As mannan is a complex and variable repertoire of oligomannoses acting as epitopes, we chemically synthesized (Σ) two major oligomannose epitopes, Man α-1,3 Man α-1,2 Man (ΣMan3) and Man α-1,3 Man α-1,2 Man α-1,2 Man (ΣMan4), and then explored how antisynthetic mannoside antibodies (AΣMA) compare with ASCA as markers of CD.
METHODS: The study involved different cohorts of CD and ulcerative colitis (UC) patients and healthy controls who had been studied previously in several medical centers in Europe, the United States, and North Africa to determine the clinical value of ASCA in terms of differential diagnosis, evolution of indeterminate colitis (IC), and serotype-phenotype correlations. The comparison of AΣMA and ASCA included a total of 1,365 subjects: 772 CD, 261 UC, 43 IC, and 289 controls.
RESULTS: The specificity of AΣMA was similar to that of ASCA (89% vs 93%), although the sensitivity was lower (38% vs 55%). Unexpectedly, 24% of the CD patients who were negative for ASCA and/or other CD-associated serologic markers were positive for AΣMA. AΣMA were associated with colonic involvement in CD (odds ratio [OR] 1.609, 95% confidence interval [CI] 1.033–2.506, P = 0.03) and were 100% predictive of CD in patients with IC.
CONCLUSIONS: AΣMA reveal the heterogeneity of the antioligomannose antibody response in CD patients and increase the sensitivity of CD diagnosis when combined with ASCA. The subset of ASCA-negative CD patients diagnosed by AΣMA had preferentially a colonic involvement, which confirms the high predictive value of AΣMA for determining IC evolution toward CD.  相似文献   
10.
BACKGROUND: Little is known about the relationship between colonic inflammation and Candida albicans colonization. Galectin-3 (Gal-3) is an intestinal lectin that binds to specific C. albicans glycans and is involved in inflammation. METHODS: Colitis was experimentally induced in wild-type and Gal3(-/-) mice using dextran sulfate sodium (DSS) before oral administration of C. albicans. Yeast recovered from stools was quantified. The presence of yeast and inflammation were evaluated in sections of colon by histologic examination, quantification of myeloperoxidase (MPO) activity, and by gene expression for cytokines and innate immune receptors. Serum from mice was collected for determination of anti-yeast mannan antibodies, including anti-Saccharomyces cerevisiae antibodies (ASCA), which are biomarkers of an inflammatory bowel disease. RESULTS: Inflammation strongly promoted C. albicans colonization. Conversely, C. albicans augmented inflammation induced by DSS, as assessed by histologic scores, MPO activity, and tumor necrosis factor (TNF)-alpha and Toll-like receptor (TLR)-2 expression. C. albicans colonization generated ASCA. The absence of Gal-3 reduced DSS inflammation and abolished the response of TLR-2 and TNF-alpha to C. albicans colonization. CONCLUSIONS: DSS-induced colitis provides a model for establishing C. albicans colonization in mice. This model reveals that C. albicans augments inflammation and confirms the role of Gal-3 in both inflammation and the control of host responses to C. albicans.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号