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排序方式: 共有477条查询结果,搜索用时 15 毫秒
51.
Kaltenbrun E Tandon P Amin NM Waldron L Showell C Conlon FL 《Birth defects research. Part A, Clinical and molecular teratology》2011,91(6):495-510
Congenital heart defects affect nearly 1% of all newborns and are a significant cause of infant death. Clinical studies have identified a number of congenital heart syndromes associated with mutations in genes that are involved in the complex process of cardiogenesis. The African clawed frog, Xenopus, has been instrumental in studies of vertebrate heart development and provides a valuable tool to investigate the molecular mechanisms underlying human congenital heart diseases. In this review, we discuss the methodologies that make Xenopus an ideal model system to investigate heart development and disease. We also outline congenital heart conditions linked to cardiac genes that have been well studied in Xenopus and describe some emerging technologies that will further aid in the study of these complex syndromes. 相似文献
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Tandon VK Yadav DB Chaturvedi AK Shukla PK 《Bioorganic & medicinal chemistry letters》2005,15(13):3288-3291
A series of (1,4)-naphthoquinono [3,2-c]-1H-pyrazoles and their (1,4)-naphthohydroquinone derivatives 2-7 were synthesized and evaluated for antifungal, antibacterial, and anticancer activities. The structure-activity relationship of these compounds was studied and the results show that the compound 2b exhibited in vitro antifungal activity against Candida albicans and Cryptococcus neoformans, and also possessed antibacterial profile against Klebsiella pneumoniae and Escherichia coli whereas 1c showed anticancer activity against Walker 256 Carcinosarcoma in rats. 相似文献
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55.
Shrivastava A Tiwari M Sinha RA Kumar A Balapure AK Bajpai VK Sharma R Mitra K Tandon A Godbole MM 《The Journal of biological chemistry》2006,281(28):19762-19771
Molecular iodine (I2) is known to inhibit the induction and promotion of N-methyl-n-nitrosourea-induced mammary carcinogenesis, to regress 7,12-dimethylbenz(a)anthracene-induced breast tumors in rat, and has also been shown to have beneficial effects in fibrocystic human breast disease. Cytotoxicity of iodine on cultured human breast cancer cell lines, namely MCF-7, MDA-MB-231, MDA-MB-453, ZR-75-1, and T-47D, is reported in this communication. Iodine induced apoptosis in all of the cell lines tested, except MDA-MB-231, shown by sub-G1 peak analysis using flow cytometry. Iodine inhibited proliferation of normal human peripheral blood mononuclear cells; however, it did not induce apoptosis in these cells. The iodine-induced apoptotic mechanism was studied in MCF-7 cells. DNA fragmentation analysis confirmed internucleosomal DNA degradation. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling established that iodine induced apoptosis in a time- and dose-dependent manner in MCF-7 cells. Iodine-induced apoptosis was independent of caspases. Iodine dissipated mitochondrial membrane potential, exhibited antioxidant activity, and caused depletion in total cellular thiol content. Western blot results showed a decrease in Bcl-2 and up-regulation of Bax. Immunofluorescence studies confirmed the activation and mitochondrial membrane localization of Bax. Ectopic Bcl-2 overexpression did not rescue iodine-induced cell death. Iodine treatment induces the translocation of apoptosis-inducing factor from mitochondria to the nucleus, and treatment of N-acetyl-L-cysteine prior to iodine exposure restored basal thiol content, ROS levels, and completely inhibited nuclear translocation of apoptosis-inducing factor and subsequently cell death, indicating that thiol depletion may play an important role in iodine-induced cell death. These results demonstrate that iodine treatment activates a caspase-independent and mitochondria-mediated apoptotic pathway. 相似文献
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Ravi Tandon Maria T. M. Giret Devi SenGupta Vanessa A. York Andrew A. Wiznia Michael G. Rosenberg Esper G. Kallas Lishomwa C. Ndhlovu Douglas F. Nixon 《PloS one》2012,7(9)
As perinatally HIV-1-infected children grow into adolescents and young adults, they are increasingly burdened with the long-term consequences of chronic HIV-1 infection, with long-term morbidity due to inadequate immunity. In progressive HIV-1 infection in horizontally infected adults, inflammation, T cell activation, and perturbed T cell differentiation lead to an “immune exhaustion”, with decline in T cell effector functions. T effector cells develop an increased expression of CD57 and loss of CD28, with an increase in co-inhibitory receptors such as PD-1 and Tim-3. Very little is known about HIV-1 induced T cell dysfunction in vertical infection. In two perinatally antiretroviral drug treated HIV-1-infected groups with median ages of 11.2 yr and 18.5 yr, matched for viral load, we found no difference in the proportion of senescent CD28−CD57+CD8+ T cells between the groups. However, the frequency of Tim-3+CD8+ and Tim-3+CD4+ exhausted T cells, but not PD-1+ T cells, was significantly increased in the adolescents with longer duration of infection compared to the children with shorter duration of HIV-1 infection. PD-1+CD8+ T cells were directly associated with T cell immune activation in children. The frequency of Tim-3+CD8+ T cells positively correlated with HIV-1 plasma viral load in the adolescents but not in the children. These data suggest that Tim-3 upregulation was driven by both HIV-1 viral replication and increased age, whereas PD-1 expression is associated with immune activation. These findings also suggest that the Tim-3 immune exhaustion phenotype rather than PD-1 or senescent cells plays an important role in age-related T cell dysfunction in perinatal HIV-1 infection. Targeting Tim-3 may serve as a novel therapeutic approach to improve immune control of virus replication and mitigate age related T cell exhaustion. 相似文献
58.
CE Ormsby D Sengupta R Tandon SG Deeks JN Martin RB Jones MA Ostrowski KE Garrison JA Vázquez-Pérez G Reyes-Terán DF Nixon 《PloS one》2012,7(8):e41021
Human endogenous retroviruses (HERV) are remnants of ancestral retroviral infections integrated into the germ line, and constitute approximately 8% of the genome. Several autoimmune disorders, malignancies, and infectious diseases such as HIV-1 are associated with higher HERV expression. The degree to which HERV expression in vivo results in persistent inflammation is not known. We studied the association of immune activation and HERV-K expression in 20 subjects with chronic, untreated progressive HIV-1 infection and 10 HIV-1 negative controls. The mean HERV-K gag and env RNA expression level in the HIV-1 infected cohort was higher than in the control group (p = 0.0003), and was negatively correlated with the frequency of activated CD38+HLA-DR+CD4+ T cells (Rho = −0.61; p = 0.01) and activated CD38+HLA-DR+CD8+ T cells (Rho = −0.51; p = 0.03). Although HIV-infected persons had higher levels of HERV-K RNA expression (as expected), the level of RNA expression was negatively associated with level of T cell activation. The mechanism for this unexpected association remains to be defined. 相似文献
59.
Mitsuteru Suzuki Pramod Tandon Masaya Ishikawa Takayuki Toyomasu 《Plant biotechnology reports》2008,2(2):123-131
Vitrification methods are convenient for cryopreserving plant specimens, as the specimens are plunged directly into liquid
nitrogen (LN) from ambient temperatures. However, tissues and species with poor survival are still not uncommon. The development
of vitrification solutions with high survival that cover a range of materials is important. We attempted to develop new vitrification
solutions using bromegrass cells and found that VSL, comprising 20% (w/v) glycerol, 30% (w/v) ethylene glycol, 5% (w/v) sucrose,
10% (w/v) DMSO and 10 mM CaCl2, gave the highest survival following cryopreservation, as determined by fluorescein diacetate staining. However, the cryopreserved
cells showed little regrowth, for unknown reasons. To check its applicability, VSL was used to cryopreserve gentian axillary
buds and the performance was compared with those of conventional vitrification solutions. Excised gentian stem segments with
axillary buds (shoot apices) were two-step precultured with sucrose to induce osmotic tolerance prior to cryopreservation.
Gentian axillary buds cryopreserved using VSL following the appropriate preculturing approach exhibited 78% survival (determined
by the regrowth capacity), which was comparable to PVS2 and PVS1 and far better than PVS3. VSL had a wider optimal incubation
time (20–45 min) than PVS2 and was more suitable for cryopreserving gentian buds. The optimal duration of the first step of
the preculture was 7–11 days, and preculturing with sucrose and glucose gave a much higher survival than fructose and maltose.
VSL was able to vitrify during cooling to LN temperatures, as glass transition and devitrification points were detected in
the warming profiles from differential scanning calorimetry. VSL and its derivative, VSL+, seem to have the potential to be
good alternatives to PVS2 for the cryopreservation of some materials, as exemplified by gentian buds.
Mitsuteru Suzuki, Pramod Tandon and Masaya Ishikawa contributed equally to the work. 相似文献
60.
A theoretical investigation of capillary-tissue fluid exchange has been studied including the characteristics and influence of the boundaries and media through which the fluid flows. Filtration from a cylindrical capillary into the concentrically surrounding tissue space and flow from a capillary into the tissue across a thin membrane are analyzed in detail. In has been observed that the filtration efficiency of the functional unit decreases as the viscosity of the peripheral layer increases. Contrary to the results of Apelblat [17], the slip velocity at the porous boundary plays a dominant role in filtration efficiency. It has also been noticed that the filtration efficiency decreases as the slip velocity at the porous boundary increases. 相似文献