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91.
Admixed populations such as African Americans and Hispanic Americans are often medically underserved and bear a disproportionately high burden of disease. Owing to the diversity of their genomes, these populations have both advantages and disadvantages for genetic studies of complex phenotypes. Advances in statistical methodologies that can infer genetic contributions from ancestral populations may yield new insights into the aetiology of disease and may contribute to the applicability of genomic medicine to these admixed population groups. 相似文献
92.
Fatigue is often reported after long duration flights. Mild hypobaric hypoxia caused by pressurisation may be involved in this effect through disruption of circadian rhythms, independently of the number of time zones crossed. In this controlled crossover study, we assessed the effects of two levels of hypoxia equivalent to 8000 and 12,000 ft on the circadian rhythm of plasma cortisol, a marker of the circadian time structure. Sixteen healthy young male volunteers (23-39 years) were exposed in a hypobaric chamber for 8 h (08:00-16:00 h) to 8000 ft, followed 4 weeks later to 12,000 ft. Plasma cortisol was assayed during two 24-h cycles (control and hypoxic exposure) every 2h in all subjects. We found a significant change in the pattern of cortisol secretion during both hypoxic exposures, with an initial fall in cortisol followed by a transient rebound, whereas the phase and the 24-h mean level remained unchanged. The change in cortisol pattern followed the alterations in autonomic balance assessed by heart rate variability (HRV) spectral analysis. The normalised high frequencies and the low-to-high frequencies ratio showed a significant shift toward sympathetic dominance with some differences in time course for both altitudes studied. HRV analysis improved the interpretation of cortisol 24-h profiles. Our data, which strongly suggest that prolonged mild hypoxia alters the expression of cortisol circadian rhythm, should be taken into account to interpret secretory rhythm changes after transmeridian flights. 相似文献
93.
Jakóbkiewicz-Banecka J Kloska A Stepnowska M Banecki B Wegrzyn A Wegrzyn G 《Mutation research》2005,578(1-2):175-186
A simple bacterial model for studying effects of human mutations in vivo, when homologous genes exist in bacterial and human cells, is presented. We have constructed Escherichia coli strains bearing different alleles of the metF gene, an ortologue of human MTHFR gene, coding for 5,10-methylenetetrahydrofolate reductase. These strains bear a null mutation in the chromosomal metF gene and different metF alleles on plasmid(s), and thus there are merozygotes mimicking wild-type homozygotes, heterozygotes and recessive mutant homozygotes. The A177V mutantion in metF corresponds to one of the most common MTHFR polymorphism, A222V, which has been shown to be associated with increased levels of homocysteine in plasma that, in turn, causes many serious medical problems. Results of relatively simple and quick experiments with these strains are compatible with previously published reports on effects of the A222V substitution in the product of MTHFR gene. In addition, these results suggest either impairment of formation of heterodimers and/or heterotetramers by wild-type and A177V metF variants or dominance of the wild-type polypepides in such structures. Moreover, positive effects of folic acid and vitamins B2 and B12 on physiology of the mutant cells, suggested on the basis of clinical studies, is confirmed. Therefore, we conclude that the bacterial model described in this report may be a useful tool in studies on human mutations. 相似文献
94.
Wilhelm P Wiede F Meissner A Donhauser N Bogdan C Körner H 《Microbes and infection / Institut Pasteur》2005,7(15):217-1468
The pro-inflammatory cytokine TNF is essential for a protective immune response to some but not all strains of Leishmania major. TNF-deficient mice of a resistant genetic background succumbed rapidly to an infection with L. major BNI. Another member of the TNF superfamily, Fas ligand (FasL), has also been reported to be critical for the immune response to L. major. To test the relative importance of TNF versus FasL for the control of L. major BNI, we infected wildtype C57BL/6 (B6.WT), B6.TNF(-/-), B6.gld and C57BL/6.gld x TNF(-/-) (B6.gld.TNF(-/-)) double-negative mice. Visceral, fatal disease was only observed in B6.TNF(-/-) mice, but not in B6 gld mice. The course of infection and the immune response of B6.gld.TNF(-/-) mice were similar to those of B6.TNF(-/-) mice. B6.gld.TNF(-/-) mice had a high tissue parasite burden and expressed prominent amounts of inducible nitric oxide synthase (iNOS) in the skin, the lymph nodes (LN) and the spleen as previously reported for B6.TNF(-/-) mice, whereas the tissue parasite load and the iNOS expression of B6.gld mice resembled that of B6.WT controls. Neither the TNF- nor the FasL-deficiency exerted a detectable intrinsic effect on the proliferation of T cells. Thus, TNF, but not FasL is essential for the control of L. major BNI. The discrepancy between these and other published data are most likely due to the use of different strains of the pathogen. 相似文献
95.
Bogdan Flis Jacek Hennig Danuta Strzelczyk-yta Christiane Gebhardt Waldemar Marczewski 《Molecular breeding : new strategies in plant improvement》2005,15(1):95-101
A novel locus for extreme resistance to Potato virus Y (PVY), Ry-fsto, was identified on potato chromosome XII. The gene Ry-fsto has been introgressed from the wild potato species Solanum stoloniferum. Inheritance of Ry-fsto in the tetraploid potato population Rysto was consistent with the model of a single, dominant gene. Bulked segregant analysis identified an ISSR (inter-simple sequence repeat) marker UBC 857980 linked to Ry-fsto. This marker mapped to linkage group XII of a reference potato RFLP (restriction fragment length polymorphism) map. Chromosome XII specific RFLP markers were converted into PCR-based STS and CAPS markers and tested for linkage with Ry-fsto in the population Rysto. CAPS marker GP122718 was tightly linked to the resistance gene and was successfully used to identify Polish and German cultivars expressing extreme resistance to PVY. This indicates that the source of Ry-fsto has been widely utilized in various potato breeding programs and can be monitored by a diagnostic marker in marker-assisted selection. 相似文献
96.
Mattner J Wandersee-Steinhäuser A Pahl A Röllinghoff M Majeau GR Hochman PS Bogdan C 《Journal of immunology (Baltimore, Md. : 1950)》2004,172(12):7574-7582
Type I IFNs (IFN-alphabeta) exert potent antiviral and immunoregulatory activities during viral infections, but their role in bacterial or protozoan infections is poorly understood. In this study, we demonstrate that the application of low, but not of high doses of IFN-beta protects 60 or 100% of BALB/c mice from progressive cutaneous and fatal visceral disease after infection with a high (10(6)) or low (10(4)) number of Leishmania major parasites, respectively. IFN-beta treatment of BALB/c mice restored the NK cell cytotoxic activity, increased the lymphocyte proliferation, and augmented the production of IFN-gamma and IL-12 in the draining lymph node. Low, but not high doses of IFN-beta caused enhanced tyrosine phosphorylation of STAT1 and STAT4, suppressed the levels of suppressor of cytokine signaling-1, and up-regulated the expression of inducible NO synthase in vivo. The IFN-beta-induced increase of IFN-gamma production was dependent on STAT4. Protection by IFN-beta strictly required the presence of inducible NO synthase. In the absence of STAT4 or IL-12, IFN-beta led to an amelioration of the cutaneous and visceral disease, but was unable to prevent its progression. These results identify IFN-beta as a novel cytokine with a strong, dose-dependent protective effect against progressive cutaneous leishmaniasis that results from IL-12- and STAT4-dependent as well as -independent events. 相似文献
97.
Schwartz MS Desai RB Bi S Miller AR Matuszewski BK 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2006,837(1-2):116-124
A method for the determination of a prostaglandin D(2) receptor antagonist (I, a compound being evaluated for the prevention of niacin induced flushing) and its acyl glucuronide metabolite (II) in human plasma is presented. The method utilized high performance liquid chromatography (HPLC) with tandem mass spectrometric (MS/MS) detection using an atmospheric pressure chemical ionization (APCI) interface operated in the positive ionization mode. The product ion was a radical cation generated via a homolytic bond cleavage. A chemical analog of the drug was used as internal standard (III). The acyl glucuronide metabolite (II) was detected using the same precursor-to-product ion transition used for the parent compound after chromatographic separation of I and II. Drug and metabolite were extracted using semi-automated, 96-well format solid phase extraction (SPE), and chromatography was performed using a reverse phase analytical column with an isocratic mobile phase. The chromatographic retention factor (k') of II was found to be highly sensitive to mobile phase formic acid concentration. An adjustment in mobile phase formic acid concentration improved the chromatographic separation between II and a mono-hydroxylated metabolite after an unexpected lack of MS/MS selectivity between the two molecules was observed. The dependence of retention factor on formic acid concentration (k' increased as formic acid concentration decreased) was thought to indicate polar interactions between II and the stationary phase. The stability of II in spiked human plasma was determined. The rate of hydrolysis back to parent compound was relatively low (approximately 0.1 and 0.5% per hour at room temperature and 4 degrees C, respectively) indicating that significant changes in analyte concentrations did not occur during sample processing. The concentration range of the assay was 10-2500 ng/mL for both drug and glucuronide metabolite. 相似文献
98.
Generation of mice harboring a Sox6 conditional null allele 总被引:1,自引:0,他引:1
99.
Sylvie Cortial Bogdan I. Iorga Gilles Truan Philippe Meyer Jamal Ouazzani 《FEBS letters》2010,584(18):3916-3922
NfrA1 nitroreductase from the Gram-positive bacterium Bacillus subtilis is a member of the NAD(P)H/FMN oxidoreductase family. Here, we investigated the reactivity, the structure and kinetics of NfrA1, which could provide insight into the unclear biological role of this enzyme. We could show that NfrA1 possesses an NADH oxidase activity that leads to high concentrations of oxygen peroxide and an NAD+ degrading activity leading to free nicotinamide. Finally, we showed that NfrA1 is able to rapidly scavenge H2O2 produced during the oxidative process or added exogenously.
Structured summary
MINT-7990140: nfrA1 (uniprotkb:P39605) and nfrA1 (uniprotkb:P39605) bind (MI:0407) by X-ray crystallography (MI:0114) 相似文献100.
Foltyn W Kos-Kudła B Siemińska L Zemczak A Strzelczyk J Marek B Kajdaniuk D Nowak M Borowska M Jurecka-Lubienicka B 《Endokrynologia Polska》2006,57(2):160-165
Neuroendocrine tumors are frequently associated with other primary malignancies. Plasmablastic lymphoma is a rare, aggressive neoplasm, derived from large B-cell, associated with human immunodeficiency virus infection. Plasmablastic lymphoma cells share many cytomorphologic and immunophenotypic features with plasmablastic cells, causing some diagnostic problems. We present a unique case of coexisting two very uncommon neoplasms: plasmablastic lymphoma and neuroendocrine carcinoma in 54-years-old men. This is the first report of caecum localization of plasmablastic lymphoma. Presented case images diagnostic problems in rare neoplasms. 相似文献