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261.
Santra BK Reddy PA Neelakanta G Mahadevan S Nethaji M Chakravarty AR 《Journal of inorganic biochemistry》2002,89(3-4):191-196
Complex [Cu(dpq)(2)(H(2)O)](ClO(4))(2).H(2)O (1), where dpq is dipyrido-[3,2-D:2',3'-f]-quinoxaline, has been prepared by reacting copper(II) perchlorate hexahydrate with dpq in methanol and structurally characterized. The complex crystallizes in the triclinic space group P-1 with the unit cell parameters a=8.646(2) A, b=12.290(5) A, c=14.283(4) A, alpha=94.01(2) degrees, beta=91.69(2) degrees,gamma=101.60 (3) degrees, V=1481.7(8) A(3) and Z=2. The structure, refined to R=0.0505 and R(w)=0.1441 for 5212 reflections with I>2sigma (I) using 440 parameters, shows the presence of a CuN(4)O chromophore in an axially compressed distorted trigonal-bipyramidal structure. The Cu-N distances lie in the range 1.969(3)-2.103(3) A. The Cu-OH(2) distance is 2.145(3) A. The complex is one-electron paramagnetic and exhibits a visible spectral d-d band at 718 nm in MeCN. It shows a quasi-reversible cyclic voltammetric response at 0.091 V (DeltaE(p)=229 mV) at 50 mV s(-1) in MeCN-0.1 M TBAP for the Cu(II)/Cu(I) couple. In 50 mM Tris-HCl/0.1 M KCl buffer-DMF mixture (1:4 v/v, pH 7.2), the couple appears at 0.089 V versus SCE. The complex undergoes facile reduction with sodium ascorbate in an aqueous DMF mixture (4:1 v/v) to form an unstable brown Cu(I) species (lambda(max)=440 nm, epsilon=7480 M(-1) cm(-1)) which converts to 1 on exposure to air giving a turnover frequency of ca. 400. Binding studies revealed that 1 is an efficient binder to calf thymus DNA. Complex 1 on reaction with supercoiled (SC) DNA in presence of ascorbic acid in a 50 mM Tris-HCl/50 mM NaCl buffer (pH 7.2) shows nuclease activity which is 4.5 times greater than that of the phen analogue. 相似文献
262.
MOTIVATION: Chromosomal segments that share common ancestry, either through genomic duplication or species divergence, are said to be segmental homologs of one another. Their identification allows researchers to leverage knowledge of model organisms for use in other systems and is of value for studies of genome evolution. However, identification and statistical evaluation of segmental homologies can be a challenge when the segments are highly diverged. RESULTS: We describe a flexible dynamic programming algorithm for the identification of segments having multiple homologous features. We model the probability of observing putative segmental homologies by chance and incorporate our findings into the parameterization of the algorithm and the statistical evaluation of its output. Combined, these findings allow segmental homologies to be identified in comparisons within and between genomic maps in a rigorous, rapid, and automated fashion. 相似文献
263.
p190-B RhoGAP regulates mammary ductal morphogenesis 总被引:1,自引:0,他引:1
Chakravarty G Hadsell D Buitrago W Settleman J Rosen JM 《Molecular endocrinology (Baltimore, Md.)》2003,17(6):1054-1065
Previous studies from our laboratory have demonstrated that p190-B RhoGAP (p190-B) is differentially expressed in the Cap cells of terminal end buds (TEBs) and poorly differentiated rodent mammary tumors. Based on these observations we hypothesized that p190-B might play an essential role in invasion of the TEBs into the surrounding fat pad during ductal morphogenesis. To test this hypothesis, mammary development was studied in p190-B-deficient mice. A haploinsufficiency phenotype was observed in p190-B heterozygous mice as indicated by decreased number and rate of ductal outgrowth(s) at 3, 4, and 5 wk of age when compared with their wild-type littermates. This appeared to result from decreased proliferation in the Cap cells of the TEBs, a phenotype remarkably similar to that observed previously in IGF-I receptor null mammary epithelium. Furthermore, decreased expression of insulin receptor substrates 1 and 2 were observed in TEBs of p190-B heterozygous mice. These findings are consistent with decreased IGF signaling observed previously in p190-B-/- mouse embryo fibroblasts. To further assess if this defect was cell autonomous or due to systemic endocrine effects, the mammary anlagen from p190-B+/+, p190-B+/-, and p190-B-/- mice was rescued by transplantation into the cleared fat pad of recipient Rag1-/- mice. Surprisingly, as opposed to 75-80% outgrowths observed using wild-type donor epithelium, only 40% of the heterozygous and none of the p190-B-/- epithelial transplants displayed any outgrowths. Together, these results suggest that p190-B regulates ductal morphogenesis, at least in part, by modulating the IGF signaling axis. 相似文献
264.
Mark?C?GenoveseEmail author Eliza?F?Chakravarty Eswar?Krishnan Larry?W?Moreland 《Arthritis research & therapy》2003,6(1):R73
The objective of this study was to evaluate the safety and possible efficacy of IFN-β-1a for the treatment of patients with rheumatoid arthritis (RA). Twenty-two patients with active RA were enrolled in a phase II randomized, double-blind, placebo-controlled trial of 30 μg IFN-β-1a by weekly self-injection for 24 weeks. The primary outcome of the study was safety. Secondary outcomes included the proportion of patients achieving an American College of Rheumatology (ACR) 20 response at 24 weeks. There were no significant differences in adverse events reported in the two groups. Fewer than 20% of patients in each arm of the study achieved an ACR 20 response at 24 weeks (P = 0.71). Sixty-nine percent of patients receiving IFN-β and 67% receiving placebo terminated the study early, most of them secondary to a perceived lack of efficacy. Overall, IFN-β-1a had a safety profile similar to that of placebo. There were no significant differences in the proportion of patients achieving an ACR 20 response between the two groups. 相似文献
265.
266.
Structural and virological studies of the stages of virus replication that are affected by antirhinovirus compounds 下载免费PDF全文
Zhang Y Simpson AA Ledford RM Bator CM Chakravarty S Skochko GA Demenczuk TM Watanyar A Pevear DC Rossmann MG 《Journal of virology》2004,78(20):11061-11069
Pleconaril is a broad-spectrum antirhinovirus and antienterovirus compound that binds into a hydrophobic pocket within viral protein 1, stabilizing the capsid and resulting in the inhibition of cell attachment and RNA uncoating. When crystals of human rhinovirus 16 (HRV16) and HRV14 are incubated with pleconaril, drug occupancy in the binding pocket is lower than when pleconaril is introduced during assembly prior to crystallization. This effect is far more marked in HRV16 than in HRV14 and is more marked with pleconaril than with other compounds. These observations are consistent with virus yield inhibition studies and radiolabeled drug binding studies showing that the antiviral effect of pleconaril against HRV16 is greater on the infectivity of progeny virions than the parent input viruses. These data suggest that drug integration into the binding pocket during assembly, or at some other late stage in virus replication, may contribute to the antiviral activity of capsid binding compounds. 相似文献
267.
The extracellular matrix is fast emerging as important component mediating cell-cell interactions, along with its established role as a scaffold for cell support. Collagen, being the principal component of extracellular matrix, has been implicated in a number of pathological conditions. However, collagens are complex protein structures belonging to a large family consisting of 28 members in humans; hence, there exists a lack of in depth information about their structural features. Annotating and appreciating the functions of these proteins is possible with the help of the numerous biocomputational tools that are currently available. This study reports a comparative analysis and characterization of the alpha-1 chain of human collagen sequences. Physico-chemical, secondary structural, functional and phylogenetic classification was carried out, based on which, collagens 12, 14 and 20, which belong to the FACIT collagen family, have been identified as potential players in diseased conditions, owing to certain atypical properties such as very high aliphatic index, low percentage of glycine and proline residues and their proximity in evolutionary history. These collagen molecules might be important candidates to be investigated further for their role in skeletal disorders. 相似文献
268.
Natural killer (NK) cells are spontaneously cytotoxic against tumour target cells. Their number was found to be four times more in the spleen of tumour-bearing Swiss albino mice. After activation with recombinant interleukin-2 (rIL-2), NK cells were tested and found to seek out the tumour site when injected intravenously in tumour-bearing mice. Their potential for fighting tumours in vivo was further seen following adoptive transfer of rIL-2 activated NK (A-NK) cells in tumour-bearing mice. After surgical removal of tumour load, adoptive transfer of A-NK cells inhibited tumour recurrence in 92.3%cases, thereby suggesting the use of this protocol for therapeutic purposes to obtain a better outcome. 相似文献
269.
Medhavi Sudarshan Toolika Singh Abhishek Kumar Singh Ankita Chourasia Bhawana Singh Mary E. Wilson Jaya Chakravarty Shyam Sundar 《PLoS neglected tropical diseases》2014,8(12)
Introduction
Studies employing serological, DTH or conventional PCR techniques suggest a vast proportion of Leishmania infected individuals living in regions endemic for Visceral Leishmaniasis (VL) remain asymptomatic. This study was designed to assess whether quantitative PCR (qPCR) can be used for detection of asymptomatic or early Leishmania donovani infection and as a predictor of progression to symptomatic disease.Methods
The study included 1469 healthy individuals living in endemic region (EHC) including both serology-positive and -negative subjects. TaqMan based qPCR assay was done on peripheral blood of each subject using kDNA specific primers and probes.Results
A large proportion of EHC 511/1469 (34.78%) showed qPCR positivity and 56 (3.81% of 1469 subjects) had more than 1 calculated parasite genome/ml of blood. However, the number of individuals with parasite load above 5 genomes/ml was only 20 (1.36% of 1469). There was poor agreement between serological testing and qPCR (k = 0.1303), and 42.89% and 31.83% EHC were qPCR positive in seropositive and seronegative groups, respectively. Ten subjects had developed to symptomatic VL after 12 month of their follow up examination, of which eight were initially positive according to qPCR and among these, five had high parasite load.Discussion
Thus, qPCR can help us to detect significant early parasitaemia, thereby assisting us in recognition of potential progressors to clinical disease. This test could facilitate early intervention, decreased morbidity and mortality, and possibly interruption of disease transmission. 相似文献270.
Sunita Sharma Sanghamitra Ghosh Soma Singh Astha Chakravarty Ashalatha Ganesh Shweta Rajani B. N. Chakravarty 《PloS one》2014,9(10)