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排序方式: 共有1149条查询结果,搜索用时 15 毫秒
31.
32.
Felkner M Suarez L Liszka B Brender JD Canfield M 《Birth defects research. Part A, Clinical and molecular teratology》2007,79(8):617-621
BACKGROUND: Previous findings for the Texas Neural Tube Defects Project suggested that while maternal access to nutrients is adequate, bioavailability of nutrients to the fetus is compromised in NTD-affected pregnancies. Helicobacter pylori could cause nutrient loss to the fetus. Folate, B12, and ferritin are depleted in H. pylori infection; these same deficiencies are related to NTD risk. METHODS: Using H. pylori IgG ELISA Test System, we tested for H. pylori serum antibodies in participants in the population-based case-control study component of the Texas Neural Tube Defect Project conducted along the Texas-Mexico border. Case-women had pregnancies affected by NTD (anencephalus, spina bifida, encephalocele) and resided and delivered in one of the 14 Texas-Mexico border counties from 1995 through 2000. Control-women were study area residents delivering normal live births during the same period. RESULTS: Of 225 case- and 378 control-women, 103 cases and 156 controls provided questionnaire and H. pylori antibody data. H. pylori seropositivity was modestly associated with NTD-affected pregnancies (OR 1.4; 95% CI: 0.8-2.4). ORs of 2.0 or greater were seen in women younger than age 25 and with less than 7 years education. CONCLUSIONS: Our findings intimate that H. pylori could play a role in NTD causation in certain populations. While results did not provide compelling support for this proposal, subgroup findings prompt us to advocate an evaluation of this hypothesis in developing nations among populations with higher prevalence of H. pylori, marginal nutrient intake, and young childbearing age. 相似文献
33.
Dariusz Pawlak Tomasz Domaniewski Beata Sieklucka Magdalena Jakuc Krystyna Pawlak 《生物化学与生物物理学报:疾病的分子基础》2019,1865(11):165528
34.
Agnieszka Bukowska-Damska Elzbieta Skowronska-Jozwiak Beata Peplonska 《Chronobiology international》2019,36(2):171-180
Osteoporosis is an important public health problem worldwide. Among the countries with a very high population risk of fractures, there are those with the highest level of economic development. Osteoporotic fractures are the main cause of disability among elderly people, and the resultant disabilities require particularly large financial support associated not only with the direct treatment of the fracture but also with the necessity for long-term rehabilitation and care for the disabled person. Many well-established factors can have impact on bone mass and fracture risk. Recently, it has been hypothesized that working during nighttime which leads to endocrine disorders may have an indirect impact on bone physiology among night shift workers. Therefore, it can be presumed that the night shift work may contribute to the etiology of osteoporosis. The aim of our work was to make a review of the epidemiological evidence on the association between night shift work and bone mineral density or fracture risk as well as to discuss the potential biological mechanisms linking the work under this system with the development of osteoporosis. We have identified only four studies investigating the association between system of work and bone mineral density or fracture risk among workers. The findings of three out of four studies support the hypothesis. None of the studies has investigated a potential relationship between night shift work and bone turnover markers. Given that there have been no epidemiological studies in European countries that would concern working populations and the noticeable difference in the risk of osteoporosis between communities, further studies are warranted to elucidate the problem. It is presumed that further in-depth studies will not only identify the underlying factors of the disease but also contribute to developing guidelines for policy makers and employers for primary prevention of osteoporosis in workplace. 相似文献
35.
Michal Lorenz Brygida Bisikirska Beata Hanus-Lorenz Kazimierz Strzalka Aleksander F. Sikorski 《Cell biology international》1995,19(7):625-632
It was found either in Western-blot analysis or in indirect immunofluorescence microscopy that cells of the alga Chlamydomonas reinhardtii contain polypeptides cross-reacting with antibodies directed against red blood cell spectrin. The protein could also be detected by immunoprecipitation with anti-spectrin antibodies. C. reinhardtii cells contain distinct polypeptide chains reacting with antibodies directed against either α- or β-spectrin subunits. This protein was extracted from the cells with low ionic strength solution but was not with nonionic detergent. 相似文献
36.
Margarita Kirkova Elina Tzvetanova Stefani Vircheva Rositsa Zamfirova Beata Grygier Marta Kubera 《Cell biochemistry and function》2010,28(6):497-502
In vivo effects of the antidepressant fluoxetine on spleen antioxidant status of C57BL/6 mice were studied using a melanoma experimental model. After a 14‐day treatment with fluoxetine (10 mg kg?1 day?1, i.p.), the endogenous antioxidant non‐enzyme (glutathione) and enzyme (superoxide dismutase (SOD) and glutathione peroxidase (GPx)) defense systems in spleen of healthy animals were not changed; the lipid peroxidation (LP) was also unchanged. When B16F10 melanoma cells were introduced in C57BL/6 mice 2 h before fluoxetine treatment, a drug‐protective effect against the melanoma‐induced oxidative changes (increased LP and decreased total glutathione (GSH)‐level, as well as antioxidant enzyme activities) in spleen was observed. Fluoxetine dose‐dependently reduced the amounts of free oxygen radicals (hydroxyl and superoxide anion radicals), generated in chemical systems. Taken together, the present results suggest that fluoxetine, acting as antioxidant, prevents from melanoma‐induced oxidative changes in mice spleen. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
37.
Ferens-Sieczkowska M Midro A Mierzejewska-Iwanowska B Zwierz K Katnik-Prastowska I 《Glycoconjugate journal》1999,16(10):573-577
Alterations in haptoglobin (Hp) glycosylation were examined in the plasma of the first patient with carbohydrate-deficient glycoprotein syndrome (CDGS) who was described in Poland. Hp concentration in the CDGS patient plasma was low (240mg/l) and the Hp phenotype was shown to be 2-2. Three glycoforms of the Hp subunit were observed in SDS-PAGE in CDGS. The densitometric analysis and molecular weight determinations suggested that 50% of glycoforms were fully glycosylated; 30% contained three out of four and 20% only two out of four glycan units compared to those that are present in Hp derived from healthy people. Results with lectins (concanavalin A and Sambucus nigra, Maackia amurensis and Alleuria aurantia agglutinins) indicate that all three glycoforms of subunit of CDGS-Hp contained biantennary complex glycans terminated with 2,6 bound sialic acid, but without fucose or 2,3 linked sialic acid. Hp glycosylation abnormalities described in this work suggest that this case was a type I carbohydrate-deficient glycoprotein syndrome. 相似文献
38.
Libik M Pater B Elliot S Slesak I Miszalskia Z 《Zeitschrift für Naturforschung. C, Journal of biosciences》2004,59(3-4):223-228
Different organs of Mesembryanthemum crystallinum exhibit differing levels of CAM (Crassulacean acid metabolism), identifiable by quantification of nocturnal malate accumulation. Shoots and also basal parts of young leaves were observed to accumulate high concentrations of malate. It was typically found in mature leaves and especially prominent in plants subjected to salt stress. Small amount of nocturnal malate accumulation was found in roots of M. crystallinum plants following age-dependent or salinity-triggered CAM. This is an indication that malate can be also stored in non-photosynthetic tissue. Measurements of catalase activity did not produce evidence of the correlation between activity of this enzyme and the level of malate accumulation in different organs of M. crystallinum although catalase activity also appeared to be dependent on the photoperiod. In all material collected at dusk catalase activity was greater than it was observed in the organs harvested at dawn. 相似文献
39.
Bobrowicz P Davidson RC Li H Potgieter TI Nett JH Hamilton SR Stadheim TA Miele RG Bobrowicz B Mitchell T Rausch S Renfer E Wildt S 《Glycobiology》2004,14(9):757-766
A significant percentage of eukaryotic proteins contain posttranslationalmodifications, including glycosylation, which are required forbiological function. However, the understanding of the structurefunctionrelationships of N-glycans has lagged significantly due to themicroheterogeneity of glycosylation in mammalian produced proteins.Recently we reported on the cellular engineering of yeast toreplicate human N-glycosylation for the production of glycoproteins.Here we report the engineering of an artificial glycosylationpathway in Pichia pastoris blocked in dolichol oligosaccharideassembly. The PpALG3 gene encoding Dol-P-Man:Man5GlcNAc2-PP-Dolmannosyltransferase was deleted in a strain that was previouslyengineered to produce hybrid GlcNAcMan5GlcNAc2 human N-glycans.Employing this approach, combined with the use of combinatorialgenetic libraries, we engineered P. pastoris strains that synthesizecomplex GlcNAc2Man3GlcNAc2 N-glycans with striking homogeneity.Furthermore, through expression of a Golgi-localized fusionprotein comprising UDP-glucose 4-epimerase and ß-1,4-galactosyltransferase activities we demonstrate that this structure isa substrate for highly efficient in vivo galactose addition.Taken together, these data demonstrate that the artificial invivo glycoengineering of yeast represents a major advance inthe production of glycoproteins and will emerge as a practicaltool to systematically elucidate the structurefunctionrelationship of N-glycans.
1 These authors contributed equally to this work. 2 To whom correspondence should be addressed; e-mail: swildt{at}glycofi.com 相似文献
40.
Treatment of cultured C. vulgaris cells with 10(-6)-10(-4) M lead decreased their growth and chemical composition during the first 48 h of cultivation. However, at concentrations above 10(-4) M, lead is cytotoxic to Chlorella vulgaris cells, resulting in cellular fragmentation and lysis. In contrast, at concentrations below 10(-6) M lead had no influence on the growth and metabolism of C. vulgaris cells. 20-Hydroxyecdysone (20E) (10(-10)-10(-8) M) increased growth and chemical composition of C. vulgaris cells over a concentration range. Levels per cell of chlorophylls, protein, sugars are all increased by 20E treatment, when compared to non-treated control cells. However, the cultures treated with 20E and lead show a lower stimulation than the cultures treated with 20E alone. The effects of 20E mixed with lead on the growth and the level of cellular lead, chlorophyll, sugar and protein in C. vulgaris are also reported. The decreased growth and composition of C. vulgaris cells treated with lead was restored by the 20E. Application of 20E to C. vulgaris cultures reduced the impact of lead stress on growth, prevented chlorophyll, sugar and protein loss and increased phytochelatins synthesis. Furthermore, 20E did not restore toxic effect of lead on C. vulgaris cells. The combined treatment with lead and 20E appeared to have a stimulatory effect on the above parameters during the 48 h of cultivation, as compared to the control. 20E reduced the toxicity of lead and the growth recovered to the level of cells treated with 20E alone. Concentration-dependent stimulation was observed with increasing concentration of 20E and decreasing concentration of lead. 相似文献