排序方式: 共有85条查询结果,搜索用时 359 毫秒
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Preya Velji Vladyslav Nikolayevskyy Timothy Brown Francis Drobniewski 《Emerging infectious diseases》2009,15(10):1609-1616
To address conflicting results about the stability of variable number tandem repeat (VNTR) loci and their value in prospective molecular epidemiology of Mycobacterium tuberculosis, we conducted a large prospective population-based analysis of all M. tuberculosis strains in a metropolitan setting. Optimal and reproducible conditions for reliable PCR and fragment analysis, comprising enzymes, denaturing conditions, and capillary temperature, were identified for a panel of hypervariable loci, including 3232, 2163a, 1982, and 4052. A total of 2,261 individual M. tuberculosis isolates and 265 sets of serial isolates were analyzed by using a standardized 15-loci VNTR panel, then an optimized hypervariable loci panel. The discriminative ability of loci varied substantially; locus VNTR 3232 varied the most, with 19 allelic variants and Hunter-Gaston index value of 0.909 unNN. Hypervariable loci should be included in standardized panels because they can provide consistent comparable results at multiple settings, provided the proposed conditions are adhered to. 相似文献
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Ibrahim Abubakar Francis Drobniewski Jo Southern Alice J Sitch Charlotte Jackson Marc Lipman Jonathan J Deeks Chris Griffiths Graham Bothamley William Lynn Helen Burgess Bobby Mann Ambreen Imran Saranya Sridhar Chuen-Yan Tsou Vladyslav Nikolayevskyy Melanie Rees-Roberts Hilary Whitworth F Sanderson 《The Lancet infectious diseases》2018,18(10):1077-1087
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Specific Interactions between the Viral Coreceptor CXCR4 and the Biguanide-Based Compound NB325 Mediate Inhibition of Human Immunodeficiency Virus Type 1 Infection 下载免费PDF全文
Nina Thakkar Vanessa Pirrone Shendra Passic Wei Zhu Vladyslav Kholodovych William Welsh Robert F. Rando Mohamed E. Labib Brian Wigdahl Fred C. Krebs 《Antimicrobial agents and chemotherapy》2009,53(2):631-638
The present studies were conducted to better define the mechanism of action of polyethylene hexamethylene biguanide (PEHMB) (designated herein as NB325), which was shown in previous studies to inhibit infection by the human immunodeficiency virus type 1 (HIV-1). Fluorescence-activated flow cytometric analyses of activated human CD4+ T lymphocytes exposed to NB325 demonstrated concentration-dependent reductions in CXCR4 epitope recognition in the absence of altered recognition of selected CD4 or CD3 epitopes. NB325 also inhibited chemotaxis of CD4+ T lymphocytes induced by the CXCR4 ligand CXCL12. However, NB325 did not cause CXCR4 internalization (unlike CXCL12) and did not interfere with CXCL12 binding. Additional flow cytometric analyses using antibodies with distinct specificities for extracellular domains of CXCR4 demonstrated that NB325 specifically interfered with antibody binding to extracellular loop 2 (ECL2). This interaction was confirmed using competitive binding analyses, in which a peptide derived from CXCR4 ECL2 competitively inhibited NB325-mediated reductions in CXCR4 epitope recognition. Collectively, these results demonstrate that the biguanide-based compound NB325 inhibits HIV-1 infection by specifically interacting with the HIV-1 coreceptor CXCR4. 相似文献
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Vyazovskiy VV Ruijgrok G Deboer T Tobler I 《Cerebral cortex (New York, N.Y. : 1991)》2006,16(3):328-336
Regional aspects of sleep homeostasis were investigated in mice provided with a running wheel for several weeks. Electroencephalogram (EEG) spectra of the primary motor (frontal) and somatosensory cortex (parietal) were recorded for three consecutive days. On a single day (day 2) the wheel was locked to prevent running. Wheel running correlated negatively with the frontal-parietal ratio of slow-wave activity (EEG power between 0.75 and 4.0 Hz) in the first 2 h after sleep onset (r = -0.60; P < 0.01). On day 2 frontal EEG power (2.25-8.0 Hz) in non-rapid eye movement sleep exceeded the level of the previous day, indicating that the diverse behaviors replacing wheel-running elicited more pronounced regional EEG differences. The frontal-parietal power ratio of the lower frequency bin (0.75-1.0 Hz) in the first 2 h of sleep after dark onset correlated positively with the duration of the preceding waking (r = 0.64; P < 0.001), whereas the power ratio in the remaining frequencies of the delta band (1.25-4.0 Hz) was unrelated to waking. The data suggest that in mice EEG power in the lower frequency, corresponding to the slow oscillations described in cats and humans, is related to local sleep homeostasis. 相似文献
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Regional differences in NREM sleep slow-wave activity in mice with congenital callosal dysgenesis 总被引:1,自引:0,他引:1
Topographic differences in the sleep EEG have been repeatedly found in humans and rodents. A frontal predominance of EEG slow-wave activity (0.75-4 Hz; delta band) during non-rapid eye movement (NREM) sleep is particularly evident under conditions of increased sleep propensity. Local aspects of neuronal connectivity in the neocortex that are modified by specific neuronal stimulation may underlie these differences. To investigate the role of altered neuronal connectivity on anterior-posterior EEG topography, sleep was recorded in mice with congenital dysgenesis of the corpus callosum (B1 strain) during baseline and after 6 h sleep deprivation (SD). In these mice neuronal connections within a hemisphere are increased due to the longitudinal Probst bundle, a structure of re-routed callosal fibers. After SD the frequencies above 1.5 Hz within the delta band in NREM sleep were reduced in B1 mice compared with control C57BL/6 mice, a strain that has a normal corpus callosum, while power in the lowest frequency band (0.75-1.0 Hz) was enhanced in B1 mice. The differences between the strains subsided in the course of recovery. The redistribution of EEG power within the delta band in the frontal region in mice with a well developed Probst bundle, suggests a role of intracortical connectivity in local sleep regulation. 相似文献
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Nikolayevskyy V Gopaul K Balabanova Y Brown T Fedorin I Drobniewski F 《Emerging infectious diseases》2006,12(9):1406-1413
A high prevalence of tuberculosis (TB) isolates that are genetically homogenous and from the Beijing family has been reported in Russia. To map TB transmission caused by these strains, new genotyping systems are needed. Mycobacterial interspersed repetitive units (MIRUs) offer the possibility of rapid PCR-based typing with comparable discrimination to IS6110 restriction fragment length polymorphism techniques. Spoligotyping and detection of IS6110 insertion in the dnaA-dnaN region were used to identify Beijing strains in 187 Mycobacterium tuberculosis isolates from Samara, Russia. The Beijing isolates were analyzed by using 12-MIRU and 3-exact tandem repeats (ETR) loci and by an expanded set of 10 additional variable number tandem repeats loci. The expanded set of 25 MIRUs provided better discrimination than the original set of 15 (Hunter-Gaston diversity index 0.870 vs. 0.625). Loci MIRU 26, 1982, and 3232 were the most polymorphic in Beijing isolates. 相似文献
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Drug-resistant tuberculosis, clinical virulence, and the dominance of the Beijing strain family in Russia 总被引:13,自引:0,他引:13
Drobniewski F Balabanova Y Nikolayevsky V Ruddy M Kuznetzov S Zakharova S Melentyev A Fedorin I 《JAMA》2005,293(22):2726-2731
Context Tuberculosis and multidrug-resistant tuberculosis is a serious public health problem in Russia. Objective To address the extent of "Beijing strain" transmission in the prison/civil sectors and the association of drug resistance, clinical, and social factors with the Beijing genotype. Design and Setting Cross-sectional population-based molecular epidemiological study of all civilian and penitentiary tuberculosis facilities in the Samara region, Russia. Patients Consecutively recruited patients with bacteriologically proven tuberculosis (n = 880). Main Outcome Measure Proportion of Beijing strains and association with drug resistance, human immunodeficiency virus infection, imprisonment, radiological, clinical, and other social factors. Results Beijing-family strains (identified by spoligotyping and composed of 2 main types by mycobacterial interspersed repetitive unit analysis) were predominant: 586/880 (66.6%; 95% confidence interval [CI], 63.4%-69.7%) with a significantly higher prevalence in the prison population (rate ratio [RR], 1.3; 95% CI, 1.2-1.5) and those aged younger than 35 years (RR, 1.2; 95% CI, 1.0-1.3). Comparable proportions were co-infected with the human immunodeficiency virus (10%), concurrent hepatitis B and C (21.6%), drank alcohol (90%), smoked (90%), and had a similar sexual history. Drug resistance was nearly 2-fold higher in patients infected with Beijing strains compared with non-Beijing strains: multidrug resistance (RR, 2.4; 95% CI, 1.9-3.0), for isoniazid (RR, 1.8; 95% CI, 1.5-2.1), for rifampicin (RR, 2.2; 95% CI, 1.7-2.7), for streptomycin (RR, 1.9; 95% CI, 1.5-2.3), and for ethambutol (RR, 2.2; 95% CI, 1.6-3.2). Univariate analysis demonstrated that male sex (odds ratio [OR], 1.5; 95% CI, 1.1-1.9), advanced radiological abnormalities (OR, 3.3; 95% CI, 1.3-8.4), homelessness (OR, 5.6; 95% CI, 1.1-6.3), and previous imprisonment (OR, 2.0; 95% CI, 1.5-2.7) were strongly associated with Beijing-strain family disease. Multivariate analysis supported previous imprisonment to be a risk factor (OR, 2.0; 95% CI, 1.4-3.3) and night sweats to be less associated (OR 0.7; 95% CI, 0.5-1.0) with Beijing-strain disease. Conclusions Drug resistance and previous imprisonment but not human immunodeficiency virus co-infection were significantly associated with Beijing-strain infection. There was evidence that Beijing isolates caused radiologically more advanced disease. 相似文献
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