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   39篇
  免费   0篇
  2022年   3篇
  2019年   2篇
  2018年   2篇
  2016年   1篇
  2014年   3篇
  2013年   4篇
  2012年   4篇
  2011年   3篇
  2010年   1篇
  2009年   2篇
  2008年   1篇
  2007年   4篇
  2006年   1篇
  2001年   1篇
  1999年   1篇
  1996年   1篇
  1995年   1篇
  1991年   1篇
  1988年   1篇
  1987年   2篇
排序方式: 共有39条查询结果,搜索用时 31 毫秒
1.
2.
3.
A 9-year-old female child of healthy parents (mother: 43 years, father: 44 years) was referred to our center because of severe mental retardation. While pedigree analysis was not contributory, two older sibs were normal and healthy. Physical examination revealed facial dysmorphism, microcephaly and hyperflexibility of all joints. Her chromosome constitution showed a mosaic pattern; mos 46,XX[98]/47,XX,+22[2]. So skin biopsy was performed and mosaic trisomy 22 was confirmed with FISH analysis (46,XX[73]/47,XX,+22[27]). Physical features of this case seemed consistent with her mosaic constitution. This report would be a demonstrative example to show the significant contribution of FISH in states of mosaicism.  相似文献   
4.
The present study was performed to investigate whether common single-nucleotide polymorphism K121Q (rs1044498) of the ENPP1 gene is associated with the known risk factors of atherosclerosis (overweight, dyslipoproteinemia, hypertension, diabetes, smoking, and hypercoagulability) in persons with acute coronary syndrome. Venous blood of 118 patients was genotyped for the polymorphism by PCR and restriction fragment length polymorphism method. In patients divided into two subgroups according to their genotype (KK and KQ + QQ), the statistically significant differences were revealed only for plasma LDL-cholesterol level and fibrinolytic activity. The carriers of minor allele (KQ + QQ) had lower LDL-cholesterol concentration and the time of fibrinolysis than the major allele homozygotes (KK). The division of patients into subgroups according to presence or absence of some risk factors for atherosclerosis showed no statistically significant differences between K121Q genotype distributions for any of the comparison.  相似文献   
5.
Simple, high-yield purification of xanthine oxidase from bovine milk.   总被引:1,自引:0,他引:1  
Xanthine oxidase, a commercially important enzyme with a wide area of application, was extracted from fresh milk, without added preservatives, using toluene and heat. The short purification procedure, with high yield, consisted of extraction, ammonium sulfate fractionation, and DEAE-Sepharose (fast flow) column chromatography. Xanthine oxidase was eluted as a single activity peak from the column using a buffer gradient. The purification fold, specific activity and yield for the purified xanthine oxidase were 328, 10.161 U/mg and 69%, respectively. The enzyme was concentrated by ultrafiltration, although 31% of the activity was lost during concentration, no change in specific activity was observed. Activity and protein gave coincident staining bands on native polyacrylamide gels. The intensity and the number of bands were dependent on the oxidative state(s) of the enzyme; reduction by 2-mercaptoethanol decreased the intensity of the slow-moving bands and increased the intensity of the fastest-moving band. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), two major bands (molecular masses of 152 and 131 kDa) were observed, accounting for > or = 95% of xanthine oxidase. Native- and SDS-PAGE showed that the purified xanthine oxidase becomes a heterodimer due to endogenous proteases.  相似文献   
6.
The central importance of translational control by post-translational modification has spurred major interest in regulatory pathways that control translation. One such pathway uniquely adds hypusine to eukaryotic initiation factor 5A (eIF5A), and thereby affects protein synthesis and, subsequently, cellular proliferation through an unknown mechanism. Using a novel conditional knockout mouse model and a Caenorhabditis elegans knockout model, we found an evolutionarily conserved role for the DOHH-mediated second step of hypusine synthesis in early embryonic development. At the cellular level, we observed reduced proliferation and induction of senescence in 3T3 Dohh−/− cells as well as reduced capability for malignant transformation. Furthermore, mass spectrometry showed that deletion of DOHH results in an unexpected complete loss of hypusine modification. Our results provide new biological insight into the physiological roles of the second step of the hypusination of eIF5A. Moreover, the conditional mouse model presented here provides a powerful tool for manipulating hypusine modification in a temporal and spatial manner, to analyse both how this unique modification normally functions in vivo as well as how it contributes to different pathological conditions.KEY WORDS: Hypusine modification, Translational control, Cancer, Mouse models  相似文献   
7.
The aim of this study was to determine the effect of aflatoxin (AF) on spermatologic, biochemical, and testis parameters in rams, and the protective efficiency of esterified glucomannan (EG) co-administered with AF. Thirty-two Merino rams (12–14 months old) were used. The experimental design consisted of four dietary treatments. The control group was fed commercial feed. The AF group was fed with commercial feed plus 250 μg/d of total AF. The EG group received commercial feed plus 2 g/d of EG. The AF + EG group was given commercial feed plus 250 μg/d of total AF and 2 g/d of EG. There were treatment, time, and treatment-by-time interaction effects on sperm motility, abnormal spermatozoa, damaged acrosome, and dead spermatozoa (P < 0.01). The percentage of motile sperm was lower and the percentages of abnormal sperm, sperm with damaged acrosomes, and dead sperm were greater in the AF group than in the control, AF+EG, and EG groups, as from week 3 until the end of week 12 (P < 0.05). As from week 3, hyaluronidase activity in the seminal plasma increased significantly in the AF group, compared with the control. The co-administration of AF+EG was found to be effective in preventing the increase in hyaluronidase activity. As week 4, malondialdehyde (MDA) levels were significantly higher in the AF group compared with the control. The combined administration of AF+EG was found to be effective in lowering the MDA levels, increased by AF, to the levels measured in the control (P < 0.05). Although glutathione (GSH) levels were determined to have significantly decreased in the AF group in comparison to the control, it was observed that, in the group co-administered with AF and EG, particularly after week 7, the GSH levels, which had decreased owing to AF, were largely ameliorated (P < 0.05). In conclusion, AF adversely affected spermatologic, biochemical, and testis parameters, and the combined administration of EG with AF reversibly eliminated these adverse effects in rams.  相似文献   
8.
SARS‐CoV‐2 vaccines are highly efficient against severe forms of the disease, hospitalization and death. Nevertheless, insufficient protection against several circulating viral variants might suggest waning immunity and the need for an additional vaccine dose. We conducted a longitudinal study on the kinetics and persistence of immune responses in healthcare workers vaccinated with two doses of BNT162b2 mRNA vaccine with or without prior SARS‐CoV‐2 infection. No new infections were diagnosed during follow‐up. At 6 months, post‐vaccination or post‐infection, despite a downward trend in the level of anti‐S IgG antibodies, the neutralizing activity does not decrease significantly, remaining higher than 75% (85.14% for subjects with natural infection, 88.82% for vaccinated after prior infection and 78.37% for vaccinated only). In a live‐virus neutralization assay, the highest neutralization titres were present at baseline and at 6 months follow‐up in persons vaccinated after prior infection. Anti‐S IgA levels showed a significant descending trend in vaccinated subjects (p < 0.05) after 14 weeks. Cellular immune responses are present even in vaccinated participants with declining antibody levels (index ratio 1.1–3) or low neutralizing activity (30%–40%) at 6 months, although with lower T‐cell stimulation index (p = 0.046) and IFN‐γ secretion (p = 0.0007) compared to those with preserved humoral responses.  相似文献   
9.
Selenium concentrations, in blood plasma, red blood cells hair of 61 healthy children, ages 0–14 yr, were determined using hydride generation atomic absorption spectrometry. Starting from late lactation period, selenium concentrations in all these matrices were found to be increasing with age. A good correlation was found between erythrocyte and plasma, hair and plasma, and hair and erythrocyte selenium concentrations. Although plasma, erythrocyte, and hair selenium concentrations of girls seemed to be higher than that of boys (only in erythrocytes), selenium concentrations of girls were found to be significantly (p<0.002) higher than that of boys, 71±9 ng/mL, vs 65±10 ng/mL, respectively. Selenium status of Turkish children is found to be lower than that found in the literature; marginal selenium deficiency could be important in the development of some selenium deficiency could be important in the development of some selenium deficiency related diseases. There is a need for extension of this study to healthy children from different regions in Turkey and to different disease states.  相似文献   
10.
The aim of the present work was to study the effects of aflatoxin (AF) on sperm parameters in rams, and to determine the protective efficiency of esterified glucomannan (EG) co-administered with AF up to 96 h of the liquid storage of ram semen at 5 °C. Thirty-two Merino rams (12–14 months old) were used. The animals were examined for their general health status. To ensure their adaptation to the environment and the new feeding regimen, a 15-day acclimatization programme was applied to the animals, prior to the start of the study. Experimental feeding was continued for ninety-two days. The experimental design consisted of four dietary treatments. The control group (C) was fed with commercial feed. The AF group was fed with commercial feed plus 250 μg/day of total AF. The EG group received commercial feed plus 2 g/day of EG. The AF + EG group was given commercial feed plus 250 μg/day of total AF and 2 g/day of EG. In the study, ejaculates were obtained from rams twice a week for 12 weeks, using an electro-ejaculator. After collected, the ejaculates were diluted with a skimmed milk extender, and stored at 5 °C. Sperm motility and rates of abnormal and nonviable spermatozoa were determined for the different treatment groups at 5 °C at 0, 24, 48, 72 and 96 h of liquid storage.  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