排序方式: 共有63条查询结果,搜索用时 109 毫秒
21.
Tatiane Assone Fernando Vieira de Souza Karen Oliveira Gaester Luiz Augusto Marcondes Fonseca Olinda do Carmo Luiz Fernanda Malta Jo?o Renato Rebello Pinho Fernanda de Toledo Gon?alves Alberto Jose da Silva Duarte Augusto Cesar Penalva de Oliveira Jorge Casseb 《PLoS neglected tropical diseases》2014,8(9)
22.
Angelo PC Ferreira AC Fonseca VD Frade SP Ferreira CS Malta FS Pereira AK Leite HV Brum AP Pardini VC Gomes KB Cabral AC 《Genetics and molecular research : GMR》2012,11(2):1002-1012
Cryopreservation of mesenchymal stem cells from amniotic fluid is of clinical importance, as these cells can be harvested during the prenatal period and stored for use in treatments. We examined the behavior of mesenchymal stem cells from human amniotic fluid in culture that had been subjected to cryopreservation. We assessed chromosomal stability through karyotype analysis, determined whether multipotent capacity (differentiation into adipogenic, chondrogenic, and osteogenic cells) is maintained, and analyzed SOX2 and NANOG expression after thawing. Five amniotic fluid samples were cryopreserved for 150 days. No chromosomal aberrations were observed. The expression levels of NANOG and SOX2 also were quite similar before and after cryopreservation. Capacity for differentiation into adipogenic, chondrogenic, and osteogenic tissues also remained the same. We conclude that cryopreservation of amniotic fluid does not alter karyotype, NANOG/SOX2 gene expression, or multipotent capacity of stem cells that have been collected from amniotic fluid during pregnancy. 相似文献
23.
Malta E Verhagen CP Moolenaar GF Filippov DV van der Marel GA Goosen N 《DNA Repair》2008,7(10):1647-1658
UvrB is the main damage recognition protein in bacterial nucleotide excision repair and is capable of recognizing various structurally unrelated types of damage. Previously we have shown that upon binding of Escherichia coli UvrB to damaged DNA two nucleotides become extrahelical: the nucleotide directly 3' to the lesion and its base-pairing partner in the non-damaged strand. Here we demonstrate using a novel fluorescent 2-aminopurine-menthol modification that the position of the damaged nucleotide itself does not change upon UvrB binding. A co-crystal structure of B. caldotenax UvrB and DNA has revealed that one nucleotide is flipped out of the DNA helix into a pocket of the UvrB protein where it stacks on Phe249 [J.J. Truglio, E. Karakas, B. Hau, H. Wang, M.J. DellaVecchia, B. van Houten, C. Kisker, Structural basis for DNA recognition and processing by UvrB, Nat. Struct. Mol. Biol. 13 (2006) 360-364]. By mutating the equivalent of Phe249 (Tyr249) in the E. coli UvrB protein we show that on damaged DNA neither of the extrahelical nucleotides is inserted into this protein pocket. The mutant UvrB protein, however, resulted in an increased binding and incision of undamaged DNA showing that insertion of a base into the nucleotide-binding pocket is important for dissociation of UvrB from undamaged sites. Replacing the nucleotides in the non-damaged strand with a C3-linker revealed that the extruded base in the non-damaged strand is not directly involved in UvrB-binding or UvrC-mediated incision, but that its displacement is needed to allow access for residues of UvrB or UvrC to the neighboring base, which is directly opposite the DNA damage. This interaction is shown to be essential for optimal 3'-incision by UvrC. After 3'-incision base flipping in the non-damaged DNA strand is lost, indicative for a conformational change needed to prepare the UvrB-DNA complex for 5'-incision. 相似文献
24.
Freidenberg BM Blanchard EB Wulfert E Malta LS 《Applied psychophysiology and biofeedback》2002,27(4):251-260
Despite somewhat high attrition and relapse rates, cognitive–behavioral interventions for pathological gambling seem promising. As a possible remedy to these problems, we conducted a preliminary study of gambling-specific cognitive–behavior therapy (CBT) with the addition of motivational enhancement techniques (MET) for the treatment of pathological gamblers. Data on psychophysiological arousal upon exposure to imagined gambling vignettes were collected at both pre- and posttreatment. Results indicate that participants showed decreases in degree of arousal during the vignettes from pre- to posttreatment. There was also a strong dose–response relationship between reductions in gambling symptoms and reductions in arousal. These findings are discussed, as are their implications for further study of pathological gambling. 相似文献
25.
UvrB plays a key role in bacterial nucleotide excision repair. It is the ultimate damage-binding protein that interacts with both UvrA and UvrC. The oligomeric state of UvrB and the UvrAB complex have been subject of debate for a long time. Using fluorescence resonance energy transfer (FRET) between GFP and YFP fused to the C-terminal end of Escherichia coli UvrB, we unambiguously show that in solution two UvrB subunits bind to UvrA, most likely as part of a UvrA2B2 complex. This complex is most stable when both UvrA and UvrB are in the ATP-bound form. Analysis of a truncated form of UvrB shows that binding to UvrA promotes dimerization of the two C-terminal domain 4 regions of UvrB. The presence of undamaged DNA leads to dissociation of the UvrA2B2 complex, but when the ATPase site of UvrB is inactivated, the complex is trapped on the DNA. When the complex is bound to a damaged site, FRET between the two UvrB subunits could still be detected, but only as long as UvrA remains associated. Dissociation of UvrA from the damage-bound UvrB dimer leads to the reduction of the magnitude of the FRET signal, indicating that the domain 4 regions no longer interact. We propose that the UvrA-induced dimerization of the domain 4 regions serves to shield these domains from premature UvrC binding. Only after specific binding of the UvrB dimer to a damaged site and subsequent release of UvrA is the contact between the domain 4 regions broken, allowing recruitment of UvrC and subsequent incisions. 相似文献
26.
Gulnar Azevedo e Silva Lenildo de Moura Maria Paula Curado Fabio da Silva Gomes Ubirani Otero Leandro Fórnias Machado de Rezende Regina Paiva Daumas Raphael Mendon?a Guimar?es Karina Cardoso Meira Iuri da Costa Leite Joaquim Gon?alves Valente Ronaldo Ismério Moreira Rosalina Koifman Deborah Carvalho Malta Marcia Sarpa de Campos Mello Thiago Wagnos Guimar?es Guedes Paolo Boffetta 《PloS one》2016,11(2)
Many human cancers develop as a result of exposure to risk factors related to the environment and ways of life. The aim of this study was to estimate attributable fractions of 25 types of cancers resulting from exposure to modifiable risk factors in Brazil. The prevalence of exposure to selected risk factors among adults was obtained from population-based surveys conducted from 2000 to 2008. Risk estimates were based on data drawn from meta-analyses or large, high quality studies. Population-attributable fractions (PAF) for a combination of risk factors, as well as the number of preventable deaths and cancer cases, were calculated for 2020. The known preventable risk factors studied will account for 34% of cancer cases among men and 35% among women in 2020, and for 46% and 39% deaths, respectively. The highest attributable fractions were estimated for tobacco smoking, infections, low consumption of fruits and vegetables, excess weight, reproductive factors, and physical inactivity. This is the first study to systematically estimate the fraction of cancer attributable to potentially modifiable risk factors in Brazil. Strategies for primary prevention of tobacco smoking and control of infection and the promotion of a healthy diet and physical activity should be the main priorities in policies for cancer prevention in the country. 相似文献
27.
Chaos in multi-looped negative feedback systems 总被引:1,自引:0,他引:1
Non-linear control systems with multiple negative feedback loops display periodicity, quasiperiodicity and period-doubling bifurcations leading to chaos. The possibility that normal fluctuations in physiological control may result from deterministic chaos in multi-looped negative feedback systems is discussed. 相似文献
28.
Marina Candido Primi Vinícius Gonçalves Maltarollo Juliana Gallottini Magalhães Matheus Malta de Sá Carlota Oliveira Rangel-Yagui 《Journal of enzyme inhibition and medicinal chemistry》2016,31(2):283-294
The dopamine hypothesis states that decreased dopaminergic neurotransmission reduces schizophrenia symptoms. Neurokinin-3 receptor (NK3) antagonists reduce dopamine release and have shown positive effects in pre-clinical and clinical trials. We employed 2D and 3D-QSAR analysis on a series of 40 non-peptide NK3 antagonists. Multivariate statistical analysis, PCA and HCA, were performed to rational training/test set splitting and PLS regression was employed to construct all QSAR models. We constructed one highly predictive CoMFA model (q2?=?0.810 and r2?=?0.929) and acceptable HQSAR and CoMSIA models (HQSAR q2?=?0.644 and r2?=?0.910; CoMSIA q2?=?0.691, r2?=?0.911). The three different techniques provided convergent physicochemical results. All models indicate cyclopropane, piperidine and di-chloro-phenyl ring attached to cyclopropane ring and also the amide group attached to the piperidine ring could play an important role in ligand–receptor interactions. These findings may contribute to develop potential NK3 receptor antagonists for schizophrenia. 相似文献
29.
Costa EA Luppi MM Malta Mde C Luiz AP de Araujo MR Coelho FM da Fonseca FG Ecco R Resende M 《Journal of wildlife diseases》2011,47(3):690-693
Human herpesvirus type 1 (HHV-1) is widely dispersed among the human population. Although infection is often asymptomatic in humans, nonhuman primates develop a severe and often fatal infection. In August 2006, 13 black-tufted marmosets (Callithrix penincillata) from a group of 14 presented with clinical apathy, anorexia, and ataxia. Physical examination revealed conjunctivitis, erosive or ulcerative lesions on the skin, and swollen lymph nodes. Of the 14 animals captured, 10 died. Grossly, ulcers and erosions were observed on the skin of face, nasal planum, lips, and oral mucosa. Histologically, superficial vesicular and erosive stomatitis with associated basophilic intranuclear inclusion bodies in the squamous epithelium were observed. Swabs from oral lesions and tissue samples from necropsied animals were positive for HHV-1 by nested polymerase chain reaction for eight animals. 相似文献
30.
Camila Malta Romano Michael Lauck Felipe S. Salvador Célia Rodrigues Lima Lucy S. Villas-Boas Evaldo Stanislau A. Araújo José Eduardo Levi Claudio Sergio Pannuti David O’Connor Esper Georges Kallas 《PloS one》2013,8(8)