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   56篇
  免费   5篇
  61篇
  2020年   1篇
  2019年   6篇
  2017年   1篇
  2015年   3篇
  2014年   5篇
  2013年   6篇
  2012年   3篇
  2010年   3篇
  2009年   1篇
  2008年   4篇
  2007年   4篇
  2006年   4篇
  2005年   4篇
  2004年   3篇
  2002年   1篇
  2001年   1篇
  2000年   2篇
  1999年   3篇
  1998年   3篇
  1994年   2篇
  1981年   1篇
排序方式: 共有61条查询结果,搜索用时 15 毫秒
21.
Bifunctional peptidylglycine alpha-amidating enzyme (alpha-AE) catalyzes the O2-dependent conversion of C-terminal glycine-extended prohormones to the active, C-terminal alpha-amidated peptide and glyoxylate. We show that alpha-AE will also catalyze the oxidative cleavage of N-acylglycines, from N-formylglycine to N-arachidonoylglycine. N-Formylglycine is the smallest amide substrate yet reported for alpha-AE. The (V/K)app for N-acylglycine amidation varies approximately 1000-fold, with the (V/K)app increasing as the acyl chain length increases. This effect is largely an effect on the KM,app; the KM,app for N-formylglycine is 23 +/- 0.88 mM, while the KM,app for N-lauroylglycine and longer chain N-acylglycines is in the range of 60-90 microM. For the amidation of N-acetylglycine, N-(tert-butoxycarbonyl)glycine, N-hexanoylglycine, and N-oleoylglycine, the rate of O2 consumption is faster than the rate of glyoxylate production. These results indicate that there must be the initial formation of an oxidized intermediate from the N-acylglycine before glyoxylate is produced. The intermediate is shown to be N-acyl-alpha-hydroxyglycine by two-dimensional 1H-13C heteronuclear multiple quantum coherence (HMQC) NMR.  相似文献   
22.
Bifunctional peptidylglycine alpha-amidating monooxygenase (PAM) catalyzes the copper-, ascorbate-, and O(2)-dependent cleavage of C-terminal glycine-extended peptides and N-acylglycines to the corresponding amides and glyoxylate. The alpha-amidated peptides and the long-chain acylamides are hormones in humans and other mammals. Bile acid glycine conjugates are also substrates for PAM leading to the formation of bile acid amides. The (V(MAX)/K(m))(app) values for the bile acid glycine conjugates are comparable to other known PAM substrates. The highest (V(MAX)/K(m))(app) value, 3.1 +/- 0.12 x 10(5) M(-1) s(-1) for 3-sulfolithocholylglycine, is 6.7-fold higher than that for d-Tyr-Val-Gly, a representative peptide substrate. The time course for O(2) consumption and glyoxylate production indicates that bile acid glycine conjugate amidation is a two-step reaction. The bile acid glycine conjugate is first converted to an N-bile acyl-alpha-hydroxyglycine intermediate which is ultimately dealkylated to the bile acid amide and glyoxylate. The enzymatically produced bile acid amides and the carbinolamide intermediates were characterized by mass spectrometry and two-dimensional (1)H-(13)C heteronuclear multiple quantum coherence NMR.  相似文献   
23.
24.

Background

In facioscapulohumeral dystrophy (FSHD) muscle function is impaired and declines over time. Currently there is no effective treatment available to slow down this decline. We have previously reported that loss of muscle strength contributes to chronic fatigue through a decreased level of physical activity, while fatigue and physical inactivity both determine loss of societal participation. To decrease chronic fatigue, two distinctly different therapeutic approaches can be proposed: aerobic exercise training (AET) to improve physical capacity and cognitive behavioural therapy (CBT) to stimulate an active life-style yet avoiding excessive physical strain. The primary aim of the FACTS-2-FSHD (acronym for Fitness And Cognitive behavioural TherapieS/for Fatigue and ACTivitieS in FSHD) trial is to study the effect of AET and CBT on the reduction of chronic fatigue as assessed with the Checklist Individual Strength subscale fatigue (CIS-fatigue) in patients with FSHD. Additionally, possible working mechanisms and the effects on various secondary outcome measures at all levels of the International Classification of Functioning, Disability and Health (ICF) are evaluated.

Methods/Design

A multi-centre, assessor-blinded, randomized controlled trial is conducted. A sample of 75 FSHD patients with severe chronic fatigue (CIS-fatigue ≥ 35) will be recruited and randomized to one of three groups: (1) AET + usual care, (2) CBT + usual care or (3) usual care alone, which consists of no therapy at all or occasional (conventional) physical therapy. After an intervention period of 16 weeks and a follow-up of 3 months, the third (control) group will as yet be randomized to either AET or CBT (approximately 7 months after inclusion). Outcomes will be assessed at baseline, immediately post intervention and at 3 and 6 months follow up.

Discussion

The FACTS-2-FSHD study is the first theory-based randomized clinical trial which evaluates the effect and the maintenance of effects of AET and CBT on the reduction of chronic fatigue in patients with FSHD. The interventions are based on a theoretical model of chronic fatigue in patients with FSHD. The study will provide a unique set of data with which the relationships between outcome measures at all levels of the ICF could be assessed.

Trial registration

Dutch Trial Register, NTR1447.
  相似文献   
25.
We present an updated account of breast cancer treatment and of progress toward “precision” cancer therapy; we focus on new developments in diagnostic molecular pathology and breast cancer that have emerged during the past 2 years. Increasing awareness of new prognostic and predictive methodologies, and introduction of next generation sequencing has increased understanding of both tumor biology and clinical behavior, which offers the possibility of more appropriate therapeutic choices. It remains unclear which of these testing methodologies provides the most informative and cost-effective actionable results for predictive and prognostic pathology. It is likely, however, that an integrated “step-wise” approach that uses the traditional clinical-pathologic paradigms coordinated with molecular characterization of breast tumor tissue, will offer the most comprehensive and cost-effective options for individualized, “precision” therapy for patients with breast cancer.  相似文献   
26.
Donkey milk and donkey milk kefir exhibit antiproliferative, antimutagenic and antibacterial effects. We investigated the effects of donkey milk and donkey milk kefir on oxidative stress, apoptosis and proliferation in Ehrlich ascites carcinoma (EAC) in mice. Thirty-four adult male Swiss albino mice were divided into four groups as follows: group 1, administered 0.5 ml water; group 2, administered 0.5 ml water + EAC cells; group 3, administered 0.5 ml donkey milk + EAC cells; group 4, administered 0.5 ml donkey milk kefir + EAC cells. We introduced 2.5 x 106 EAC cells into each animal by subcutaneous injection. Tap water, donkey milk and donkey milk kefir were administered by gavage for 10 days. Animals were sacrificed on day 11. After measuring the short and long diameters of the tumors, tissues were processed for histology. To determine oxidative stress, cell death and proliferation iNOS and eNOS, active caspase-3 and proliferating cell nuclear antigen were assessed using immunohistochemistry. A TUNEL assay also was used to detect apoptosis. Tumor volume decreased in the donkey milk kefir group compared to the control and donkey milk groups. Tumor volume increased in the donkey milk group compared to the control group. Proliferating cell nuclear antigen levels were higher in the donkey milk kefir group compared to the control and donkey milk groups. The number of apoptotic cells was less in the donkey milk group, compared to the control, whereas it was highest in the donkey milk kefir group. Donkey milk administration increased eNOS levels and decreased iNOS levels, compared to the control group. In the donkey milk kefir group, iNOS levels were significantly lower than those of the control and donkey milk groups, while eNOS levels were similar to the control group. Donkey milk kefir induced apoptosis, suppressed proliferation and decreased co-expression of iNOS and eNOS. Donkey milk promoted development of the tumors. Therefore, donkey milk kefir appears to be more beneficial for treating breast cancer than donkey milk.  相似文献   
27.
The silkmoth chorion has provided a stimulating model for the study of evolution and developmental regulation of gene families. Previous attempts at inferring relationships among chorion sequences have been based on pairwise comparisons of overall similarity, a potentially problematic approach. To remedy this, we identified the alignable regions of low sequence variability and then analyzed this restricted database by parsimony and neighbor-joining methods. At the deepest level, the chorion sequence tree is split into two branches, called "alpha" and "beta." Within each branch, early- and late-expressing genes each constitute monophyletic groups, while the situation with middle-expressing genes remains uncertain. The HcB gene family appears to be the most basal beta-branch group, but this conclusion is qualified because the effect of gene conversion on branching order is unknown. Previous studies by Eickbush and colleagues have strongly suggested that ErA, HcA, and HcB families undergo gene conversion within a gene family, whereas the ErB family does not. The occurrence of conversion correlates with a particular tree structure; namely, branch lengths are much greater at the base of the family than at higher internodes and terminal branches. These observations raise the possibility that chorion gene families are defined by gene conversion events (reticulate evolution) rather than by descent with modification (synapomorphy).   相似文献   
28.
Intercellular adhesion molecule-3 (ICAM-3, CD50), an adhesion receptor of the immunoglobulin superfamily, is suggested to play a key role in adhesive cellular interactions during the initial phase of an immune response. We here provide evidence that ICAM-3 is abundantly expressed by cells of the human mast cell line HMC-1 and, to a lower degree, by purified skin mast cells, as demonstrated by flow-cytometry, ELISA and RT-PCR. ICAM-3 immunoprecipitated from surface biotinylated HMC-1 cells migrates as a broad band of Mr 124,000 by Western blot analysis. We also demonstrate that monoclonal antibodies directed against ICAM-3 are capable of inducing rapid HMC-1 cell aggregation, the extent of which strongly depends on the epitope recognized by the mAb applied. Interestingly, although inhibitable by two of six mAbs against LFA-1, HMC-1 aggregation induced via ICAM-3 appears to be mediated by an adhesive pathway independent of LFA-1. Dermal mast cells are also aggregated with anti-ICAM-3 mAbs, a phenomenon which has not been described before for isolated tissue mast cells. However, this process displays slower kinetics, as compared to HMC-1 cells. That anti-ICAM-3 mAbs are able to mediate biological effects is further illustrated by their capability to increase stimulation-dependent release of the pro-inflammatory cytokines interleukin-6 (IL-6) and IL-8 from HMC-1 cells. Taken together, these results indicate that ICAM-3 is not only expressed by immature and mature human mast cells, but also possesses functional relevance and may therefore play a significant role in mast cell associated processes.  相似文献   
29.
30.

Background  

Recently, a Risk Assessment methodology was applied to animal welfare issues in a report of the European Food Safety Authority (EFSA) on intensively housed calves.  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