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   87篇
  免费   13篇
  2021年   5篇
  2017年   2篇
  2016年   2篇
  2015年   7篇
  2014年   2篇
  2013年   5篇
  2012年   6篇
  2011年   10篇
  2010年   1篇
  2009年   5篇
  2008年   3篇
  2007年   7篇
  2006年   9篇
  2005年   10篇
  2004年   4篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  2000年   2篇
  1999年   2篇
  1997年   3篇
  1995年   1篇
  1994年   1篇
  1992年   2篇
  1990年   1篇
  1985年   1篇
排序方式: 共有100条查询结果,搜索用时 949 毫秒
1.
Calcium ionophores inhibit apoptosis in the IL-3-dependent cell line BAF3 and maintain the cells in a viable noncycling state. In this report, an identical effect of ionophore was also demonstrated on the multipotent IL-3-dependent progenitor cell line FDCP-MIX and on the primary IL-3-dependent cell population that could be cultured from murine bone marrow. Inhibition of apoptosis required extracellular calcium and could be blocked by cyclosporin A. Nuclei from IL-3-dependent cells were found to lack a calcium-activatable nuclease that degrades chromatin in the linker region between nucleosomes, unlike the nuclei of lymphoid cells. The mechanism of action of calcium ionophore could be divided into two distinct steps. First, ionophore induced the production of a survival factor that stimulated DNA synthesis and was identified as IL-4. Second, ionophore inhibited the cell cycle of the various IL-3-dependent cells. IL-4 production could be inhibited by cyclosporin A and required extracellular calcium, whereas cell cycle arrest did not. This implied that factor production was the step that was necessary for inhibition of apoptosis and maintenance of cell viability. This was confirmed by the use of an anti-IL-4R antibody, which blocked the inhibition of apoptosis induced by calcium ionophores.  相似文献   
2.
Morning levels of serum melatonin, FSH, LH, prolactin (PRL), progesterone and estradiol were studied by RIA during the ovarian cycle, perimenopause and menopause in 79 healthy women. FSH and LH levels showed a slight nonsignificant increase from the fertile period to perimenopause, exhibiting a significantly greater increase during menopause. PRL, progesterone and estradiol showed parallel changes, reaching lower levels during menopause. Serum melatonin levels decreased with age, attaining minimum levels in menopause. FSH and estradiol were significantly correlated with melatonin in the follicular phase, while in the luteal phase a negative correlation was found between melatonin, progesterone and estradiol. No significant correlations were noted between serum hormone levels during the perimenopausal period. In menopause, as during the follicular phase, melatonin and FSH were negatively correlated. As expected, a significant positive correlation was found between morning serum levels of melatonin and nocturnal urinary excretion of this indoleamine in all groups studied.  相似文献   
3.
The interaction of gadolinium complexes with isolated rat hepatocytes   总被引:4,自引:0,他引:4  
The lanthanide metal, gadolinium, is currently used in contrast agents for magnetic resonance imaging. We have performed a study of the interaction between isolated rat hepatocytes and 153Gd complexed to diethylene-triamine pentaacetic acid (DTPA) or to DTPA-albumin conjugates. The study shows that isolated hepatocytes are able to take up both types of 153Gd complexes. The 153Gd-DTPA-albumin complexes are apparently taken up by pinocytosis, and possibly receptor-mediated endocytosis and/or adsorptive endocytosis, whereas the uptake mechanism of 153Gd-DTPA is unknown. The 153Gd-DTPA-albumin complexes, but not the 153Gd-DTPA complex, are degraded by the cell. The degradation is inhibited by ammonium chloride. Gadolinium is slowly released back to the medium after loading of the cells with both complex types. In the experiments reported here no evidence of any adverse effects on the hepatocyte resulting from exposure to the 153Gd-complexes were observed.  相似文献   
4.
Responses in flounder (Platichthys flesus) towards benzo [a]pyrene (BaP), 2,3,3′,4,4′,5-hexachlorobiphenyl (PCB-156), and cadmium (Cd) were investigated in time-course and dose-response studies of selected biomarkers. Measurements of biliary fluorescent BaP metabolites and hepatic concentrations of PCB-156 and cadmium showed that the injected toxicants were rapidly m obilized from the muscle to the liver, but a depot effect was indicated in the highest dose groups of BaP and PCB-156 (12 mg kg-1 bodyweight). Clearest biomarker responses were found in the induction of hepatic cytochrome P450 1A (CYP1A) enzymes as a response towards BaP and PCB-156 exposure. Maximum induction of CYP1A dependent 7-ethoxyresorufin O-deethylase (EROD) activity was observed after 2 and 8 days in BaP and PCB-156-treated flounder, respectively. Positive dose-effect relationships were observed towards both compounds, but the CYP1A induction was more persistent with PCB exposure than with BaP exposure. In Cd-exposed fish, the hepatic level of metallothionein responded more slowly with highest levels observed after 16 days in the time-study. In the combined BaP + Cd treatment, the CYP1A induction was only slightly suppressed. Aspartate aminotransferase in serum appeared to be responsive towards BaP, but also towards the acetone vehicle in controls in the first part of the exposure period. Hematocrit as well as hepatic activities of aldrin epoxidase, glutathione S-transferase, and UDP-glucuronyl transferase were not responsive to any treatm ent in the present study. In general, the results demonstrate that selected biom arkers in flounder are responsive to PAH, PCB, and heavy metal pollutant exposure, indicating the applicability of this species in future environmental pollution monitoring programmes.  相似文献   
5.
Hereditary Hemochromatosis (HH) is a recessively inherited disorder of iron overload occurring commonly in subjects homozygous for the C282Y mutation in HFE gene localized on chromosome 6p21.3 in linkage disequilibrium with the human leukocyte antigen (HLA)-A locus. Although its genetic homogeneity, the phenotypic expression is variable suggesting the presence of modifying factors. One such genetic factor, a SNP microhaplotype named A-A-T, was recently found to be associated with a more severe phenotype and also with low CD8+T-lymphocyte numbers. The present study aimed to test whether the predictive value of the A-A-T microhaplotype remained in other population settings. In this study of 304 HH patients from 3 geographically distant populations (Porto, Portugal 65; Alabama, USA 57; Nord-Trøndelag, Norway 182), the extended haplotypes involving A-A-T were studied in 608 chromosomes and the CD8+ T-lymphocyte numbers were determined in all subjects. Patients from Porto had a more severe phenotype than those from other settings. Patients with A-A-T seemed on average to have greater iron stores (p = 0.021), but significant differences were not confirmed in the 3 separate populations. Low CD8+ T-lymphocytes were associated with HLA-A*03-A-A-T in Porto and Alabama patients but not in the greater series from Nord-Trøndelag. Although A-A-T may signal a more severe iron phenotype, this study was unable to prove such an association in all population settings, precluding its use as a universal predictive marker of iron overload in HH. Interestingly, the association between A-A-T and CD8+ T-lymphocytes, which was confirmed in Porto and Alabama patients, was not observed in Nord-Trøndelag patients, showing that common HLA haplotypes like A*01–B*08 or A*03–B*07 segregating with HFE/C282Y in the three populations may carry different messages. These findings further strengthen the relevance of HH as a good disease model to search for novel candidate loci associated with the genetic transmission of CD8+ T-lymphocyte numbers.  相似文献   
6.

Background

Depression is a common disorder affecting 10–15% women in the postpartum period. Postpartum depression can disrupt early mother-infant interaction, and constitutes a risk factor for early child development. Recently, attention has been drawn to the hypothesis that a low intake of seafood in pregnancy can be a risk factor for postpartum depression. Seafood is a unique dietary source of the marine omega-3 fatty acids and is a natural part of a healthy balanced diet that is especially important during pregnancy.

Methods

In a community based prospective cohort in a municipality in Western Norway, we investigated both nutritional and psychological risk factors for postpartum depression. The source population was all women who were pregnant within the period November 2009 - June 2011. The fatty acid status in red blood cells was assessed in the 28th gestation week and participants were screened for postpartum depression using the Edinburgh Postnatal Depression Scale (EPDS) three months after delivery. The aim of the present study was to investigate if a low omega-3 index in pregnancy is a possible risk factor for postpartum depression.

Results

In a simple regression model, the omega-3 index was associated with the EPDS score in a nonlinear inverse manner with an R square of 19. Thus, the low omega-3 index explained 19% of the variance in the EPDS score. The DPA content, DHA content, omega-3 index, omega-3/omega-6 ratio, total HUFA score, and the omega-3 HUFA score were all inversely correlated with the EPDS score. The EPDS scores of participants in the lowest omega-3 index quartile were significantly different to the three other omega-3 index quartiles.

Conclusion

In this study population, a low omega-3 index in late pregnancy was associated with higher depression score three months postpartum.  相似文献   
7.
In the present study we examined the ability of the amino acid derivative LTX-401 to induce cell death in cancer cell lines, as well as the capacity to induce regression in a murine melanoma model. Mode of action studies in vitro revealed lytic cell death and release of danger-associated molecular pattern molecules, preceded by massive cytoplasmic vacuolization and compromised lysosomes in treated cells. The use of a murine melanoma model demonstrated that the majority of animals treated with intratumoural injections of LTX-401 showed complete and long-lasting remission. Taken together, these results demonstrate the potential of LTX-401 as an immunotherapeutic agent for the treatment of solid tumors.  相似文献   
8.
The aim of this study was to explore how caregivers experience collaboration in rural municipalities in northern Norway. We conducted fieldwork with a dementia team in addition to seventeen qualitative in-depth interviews with formal and family caregivers. The caregivers had ethnic Sami and ethnic Norwegian affiliation. The theme ‘negotiating ethnic and ethno-political positions’ was identified through thematic analysis and developed using positioning theory. Ethnicity involves dynamic and situated personal affiliations, and participants negotiate each other's ethnic positions in practice. Negotiations of ethnic positions hamper collaboration between formal and family caregivers, and ethno-political positions reinforce stereotyped ethnic positions. This study contributes to the understanding of and the debate over positions on ethno-cultural collaboration in health care. In practice, participants negotiate the health policy concept of ‘cultural facilitation’, which must be broadened to ensure equal healthcare services.  相似文献   
9.
Hereditary hemochromatosis (HH) is a common genetic disease with iron overload in certain organs, especially the liver. Most cases are homozygous for the C282Y mutation in the HFE gene; a few are C282Y heterozygous, compound C282Y/H63D heterozygous, or have no known mutation. A third mutation, S65C, has been associated with HH, but this finding is disputed. We have studied the clinical significance of various genotypes with the S65C mutation. In a population-based screening for HH in 65,238 persons, 613 had high serum transferrin saturation in two blood samples and were invited for HFE genotyping. In 556 persons with complete data sets, we studied the serum ferritin concentration and the risk of being diagnosed with phenotypic HH in the various genotypic groups. The phenotypic diagnosis was given without knowing the genotypic result. Except for the C282Y homozygotes, no differences in median serum ferritin concentrations were found between the various genotypic groups. However, the C282Y/S65C compound heterozygous group had a higher risk of being diagnosed with phenotypic HH than the wild-type group, as did the C282Y homozygous and the C282Y/H63D compound heterozygous groups. When combined with the C282Y mutation, the S65C mutation is associated with an increased risk of being diagnosed with phenotypic HH.  相似文献   
10.
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