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31.
Talukder MA Yang F Nishijima Y Chen CA Xie L Mahamud SD Kalyanasundaram A Bonagura JD Periasamy M Zweier JL 《American journal of physiology. Heart and circulatory physiology》2011,300(2):H702-H711
There is emerging evidence that treatment with thyroid hormone (TH) can improve postischemic cardiac function. 3,5-Diiodothyropropionic acid (DITPA), a TH analog, has been proposed to be a safer therapeutic agent than TH because of its negligible effects on cardiac metabolism and heart rate. However, conflicting results have been reported for the cardiac effects of DITPA. Importantly, recent clinical trials demonstrated no symptomatic benefit in patients with DITPA despite some improved hemodynamic and metabolic parameters. To address these issues, dose-dependent effects of DITPA were investigated in mice for baseline cardiovascular effects and postischemic myocardial function and/or salvage. Mice were treated with subcutaneous DITPA at 0.937, 1.875, 3.75, or 7.5 mg·kg(-1)·day(-1) for 7 days, and the results were compared with untreated mice for ex vivo and/or in vivo myocardial ischemia-reperfusion (I/R). DITPA had no effects on baseline body temperature, body weight, or heart rate; however, it mildly increased blood pressure. In isolated hearts, baseline contractile function was significantly impaired in DITPA-pretreated mice; however, postischemic recovery was comparable between untreated and DITPA-treated groups. In vivo baseline cardiac parameters were significantly affected by DITPA, with increased ventricular dimensions and decreased contractile function. Importantly, DITPA-treated mice demonstrated high prevalence of fatal cardiac rhythm abnormalities during in vivo ischemia and/or reperfusion. There were no improvements in myocardial infarction and postischemic fractional shortening with DITPA. Myocardial sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA), phospholamban (PLB), and heat shock protein (HSP) levels remained unchanged with DITPA treatment. Thus DITPA administration impairs baseline cardiac parameters in mice and can be fatal during in vivo acute myocardial I/R. 相似文献
32.
Laurence Rohmer Michael A Jacobs Mitchell J Brittnacher Christine Fong Hillary S Hayden Didier Hocquet Eli J Weiss Matthew Radey Yves Germani Kaisar Ali Talukder Anthony J Hager John M Kemner Elizabeth H Sims-Day Susana Matamouros Kyle R Hager Samuel I Miller 《BMC genomics》2014,15(1)
Background
Shigella dysenteriae type 1 (Sd1) causes recurrent epidemics of dysentery associated with high mortality in many regions of the world. Sd1 infects humans at very low infectious doses (10 CFU), and treatment is complicated by the rapid emergence of antibiotic resistant Sd1 strains. Sd1 is only detected in the context of human infections, and the circumstances under which epidemics emerge and regress remain unknown.Results
Phylogenomic analyses of 56 isolates collected worldwide over the past 60 years indicate that the Sd1 clone responsible for the recent pandemics emerged at the turn of the 20th century, and that the two world wars likely played a pivotal role for its dissemination. Several lineages remain ubiquitous and their phylogeny indicates several recent intercontinental transfers. Our comparative genomics analysis reveals that isolates responsible for separate outbreaks, though closely related to one another, have independently accumulated antibiotic resistance genes, suggesting that there is little or no selection to retain these genes in-between outbreaks. The genomes appear to be subjected to genetic drift that affects a number of functions currently used by diagnostic tools to identify Sd1, which could lead to the potential failure of such tools.Conclusions
Taken together, the Sd1 population structure and pattern of evolution suggest a recent emergence and a possible human carrier state that could play an important role in the epidemic pattern of infections of this human-specific pathogen. This analysis highlights the important role of whole-genome sequencing in studying pathogens for which epidemiological or laboratory investigations are particularly challenging.Electronic supplementary material
The online version of this article (doi: 10.1186/1471-2164-15-355) contains supplementary material, which is available to authorized users. 相似文献33.
Muhammad Moniruzzaman Mahabubur R. Talukder Takuya Kawanishi 《Biocatalysis and Biotransformation》2013,31(1):51-58
AOT reverse micellar system was modified with DMSO for improved esterification activity of Chromobacteriumviscosum lipase (glycerol–ester hydrolase, EC 3.1.1.3). The enzymatic activity was strongly affected by the concentration of DMSO, and maximum activity was obtained at 30–40 mM. The various relevant physical parameters such as w0 (molar ratio of water to AOT), pH and reaction temperature that influence the activity of lipase were studied in order to obtain the best value and compared with those in simple AOT reverse micelles. The apparent activation energy decreased in the presence of DMSO. The stability of lipase entrapped in modified AOT systems was excellent, and the half-life was about 3.25 times than that observed in simple AOT systems at 25°C. A simple first-order deactivation model was considered to determine the deactivation rate constant. The thermodynamic stability of lipase in reverse micelles was measured by the Gibbs free energy. A fluorescence study was performed to provide information on structural changes in AOT reverse micelles which was accompanied by the addition of DMSO. 相似文献
34.
The clastogenicity of trimethyltin chloride was evaluated in human peripheral blood lymphocytes with micronucleus counts (MNC) as the endpoint. Two concentrations (0.5 micrograms and 1.0 microgram) of trimethyltin chloride were added to lymphocytes of healthy male and female subjects of different age groups, in mitogen-stimulated and serum-supplemented culture medium (RPMI 1640, Gibco) for 48 h at 37 degrees C. A significant increase in micronucleus counts was observed with both doses, which was more pronounced with the lower dose. ANOVA in male and female donors revealed significant differences between age groups (P less than 0.001), chemical concentrations (P less than 0.001) and for the interaction of these 2 factors (P less than 0.05 in females only). However, no regular increase or decrease in MNC frequencies was observed with the donor's age. Higher frequencies of MNC enhancement were observed in male individuals than in females. 相似文献
35.
36.
The ability of intraperitoneally administered cadmium chloride (0.42-6.75 mg/kg) to induce genotoxic damage in somatic and germ cells of mice was evaluated using chromosomal aberrations, sister-chromatid exchanges (SCE), micronuclei and sperm-head abnormalities as end-points. A significant increase in the frequency of chromosomal aberrations and SCEs was observed in almost all treated series when compared to the negative control. Micronucleus formation in polychromatic erythrocytes was not affected significantly except at the highest concentration used (6.75 mg/kg). Significant differences were observed in the frequency of sperm with abnormal head morphology at all concentrations tested except the lowest one. The clastogenic effects of cadmium chloride in both somatic and germinal cells are found to depend directly on the concentrations used. 相似文献
37.
The interaction between two group IV metals, the highly toxic lead and the relatively inactive and low toxic zirconium, was studied in the bone marrow chromosomes ofMus musculus in vivo. Low and high doses of zirconium oxychloride were fed orally to the experimental mice (i) 2 h before, (ii) 2 h after or (iii) together with different doses of lead nitrate. Protection against lead-induced clastogenicity was observed only when the lower dose of zirconium was administered prior to lead. All other combinations gave an additive or synergistic effect as was seen by significant increases in the frequencies of chromosomal aberrations. 相似文献
38.
Summary The action of Zirconium (Zr) on biological systems presents an enigma. It is ubiquitous, being present in nature in amounts
higher than most trace elements. It is taken up by plants from soil and water and accumulated in certain tissues. The entry
into animal systems in vivo is related to the mode of exposure and the concentration in the surrounding environment. Retention
is initially in soft tissues and then slowly in the bone. The metal is able to cross the blood brain-barrier and is deposited
in the brain and the placental barrier to enter milk. The daily human uptake has been known to be as high as 125 mg. The level
of toxicity has been found to be moderately low, both in histological and cytological studies. The toxic effects induced by
very high concentrations are nonspecific in nature. Despite the presence and retention in relatively high quantities in biological
systems, Zr has not yet been associated with any specific metabolic function. Very little information is available about its
interaction with the compounds of the genetical systems, such as nucleic acids. Apparently, the metal is neither an essential
nor toxic element in the conventional sense. However, the increasing exposure to this element through its increasing use in
new materials and following radioactive fallout, has increased the importance of the study of its effects on living organisms.
The tetravalent nature of the ionic state and the high stability of the compounds formed are important factors that need to
be considered, as also the accumulation of this element in the brain, reminiscent of the relationship between Al3+ and Alzheimer's disease. 相似文献
39.
A proinflammatory response of bovine endometrial epithelial cells to active sperm in vitro
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40.