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Search Results: 1 - 10 of 130312 matches for " V Nikolayevskyy "
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The Directly Observed Therapy Short-Course (DOTS) strategy in Samara Oblast, Russian Federation
Y Balabanova, F Drobniewski, I Fedorin, S Zakharova, V Nikolayevskyy, R Atun, R Coker
Respiratory Research , 2006, DOI: 10.1186/1465-9921-7-44
Abstract: The purpose of this study was to implement a DOTS programme in the civilian and prison sectors of Samara Region of Russia, describe the clinical features and outcomes of recruited patients, determine the proportion of individuals in the cohorts who were infected with drug resistant TB, the degree to which resistance was attributed to the Beijing TB strain family and establish risk factors for drug resistance.prospective study2,099 patients were recruited overall. Treatment outcomes were analysed for patients recruited up to the third quarter of 2003 (n = 920). 75.3% of patients were successfully treated. Unsuccessful outcomes occurred in 7.3% of cases; 3.6% of patients died during treatment, with a significantly higher proportion of smear-positive cases dying compared to smear-negative cases. 14.0% were lost and transferred out. A high proportion of new cases (948 sequential culture-proven TB cases) had tuberculosis that was resistant to first-line drugs; (24.9% isoniazid resistant; 20.3% rifampicin resistant; 17.3% multidrug resistant tuberculosis). Molecular epidemiological analysis demonstrated that half of all isolated strains (50.7%; 375/740) belonged to the Beijing family. Drug resistance including MDR TB was strongly associated with infection with the Beijing strain (for MDR TB, 35.2% in Beijing strains versus 9.5% in non-Beijing strains, OR-5.2. Risk factors for multidrug resistant tuberculosis were: being a prisoner (OR 4.4), having a relapse of tuberculosis (OR 3.5), being infected with a Beijing family TB strain (OR 6.5) and having an unsuccessful outcome from treatment (OR 5.0).The implementation of DOTS in Samara, Russia, was feasible and successful. Drug resistant tuberculosis rates in new cases were high and challenge successful outcomes from a conventional DOTS programme alone.Since the 1990s the World Health Organization Directly Observed Therapy Short Course (DOTS) management strategy has become the internationally recommended approach for tubercul
Rates of Latent Tuberculosis in Health Care Staff in Russia
Francis Drobniewski ,Yanina Balabanova,Elena Zakamova,Vladyslav Nikolayevskyy,Ivan Fedorin
PLOS Medicine , 2007, DOI: 10.1371/journal.pmed.0040055
Abstract: Background Russia is one of 22 high burden tuberculosis (TB) countries. Identifying individuals, particularly health care workers (HCWs) with latent tuberculosis infection (LTBI), and determining the rate of infection, can assist TB control through chemoprophylaxis and improving institutional cross-infection strategies. The objective of the study was to estimate the prevalence and determine the relative risks and risk factors for infection, within a vertically organised TB service in a country with universal bacille Calmette-Guérin (BCG) vaccination. Methods and Findings We conducted a cross-sectional study to assess the prevalence of and risk factors for LTBI among unexposed students, minimally exposed medical students, primary care health providers, and TB hospital health providers in Samara, Russian Federation. We used a novel in vitro assay (for gamma-interferon [IFN-γ]) release to establish LTBI and a questionnaire to address risk factors. LTBI was seen in 40.8% (107/262) of staff and was significantly higher in doctors and nurses (39.1% [90/230]) than in students (8.7% [32/368]) (relative risk [RR] 4.5; 95% confidence interval [CI] 3.1–6.5) and in TB service versus primary health doctors and nurses: respectively 46.9% (45/96) versus 29.3% (34/116) (RR 1.6; 95% CI 1.1–2.3). There was a gradient of LTBI, proportional to exposure, in medical students, primary health care providers, and TB doctors: respectively, 10.1% (24/238), 25.5% (14/55), and 55% (22/40). LTBI was also high in TB laboratory workers: 11/18 (61.1%). Conclusions IFN-γ assays have a useful role in screening HCWs with a high risk of LTBI and who are BCG vaccinated. TB HCWs were at significantly higher risk of having LTBI. Larger cohort studies are needed to evaluate the individual risks of active TB development in positive individuals and the effectiveness of preventive therapy based on IFN-γ test results.
Ethnic Variation in Inflammatory Profile in Tuberculosis
Anna K. Coussens,Robert J. Wilkinson,Vladyslav Nikolayevskyy,Paul T. Elkington,Yasmeen Hanifa,Kamrul Islam,Peter M. Timms,Graham H. Bothamley,Alleyna P. Claxton,Geoffrey E. Packe,Mathina Darmalingam,Robert N. Davidson,Heather J. Milburn,Lucy V. Baker,Richard D. Barker,Francis A. Drobniewski,Charles A. Mein,Leena Bhaw-Rosun,Rosamond A. Nuamah,Christopher J. Griffiths,Adrian R. Martineau
PLOS Pathogens , 2013, DOI: 10.1371/journal.ppat.1003468
Abstract: Distinct phylogenetic lineages of Mycobacterium tuberculosis (MTB) cause disease in patients of particular genetic ancestry, and elicit different patterns of cytokine and chemokine secretion when cultured with human macrophages in vitro. Circulating and antigen-stimulated concentrations of these inflammatory mediators might therefore be expected to vary significantly between tuberculosis patients of different ethnic origin. Studies to characterise such variation, and to determine whether it relates to host or bacillary factors, have not been conducted. We therefore compared circulating and antigen-stimulated concentrations of 43 inflammatory mediators and 14 haematological parameters (inflammatory profile) in 45 pulmonary tuberculosis patients of African ancestry vs. 83 patients of Eurasian ancestry in London, UK, and investigated the influence of bacillary and host genotype on these profiles. Despite having similar demographic and clinical characteristics, patients of differing ancestry exhibited distinct inflammatory profiles at presentation: those of African ancestry had lower neutrophil counts, lower serum concentrations of CCL2, CCL11 and vitamin D binding protein (DBP) but higher serum CCL5 concentrations and higher antigen-stimulated IL-1 receptor antagonist and IL-12 secretion. These differences associated with ethnic variation in host DBP genotype, but not with ethnic variation in MTB strain. Ethnic differences in inflammatory profile became more marked following initiation of antimicrobial therapy, and immunological correlates of speed of elimination of MTB from the sputum differed between patients of African vs. Eurasian ancestry. Our study demonstrates a hitherto unappreciated degree of ethnic heterogeneity in inflammatory profile in tuberculosis patients that associates primarily with ethnic variation in host, rather than bacillary, genotype. Candidate immunodiagnostics and immunological biomarkers of response to antimicrobial therapy should be derived and validated in tuberculosis patients of different ethnic origin.
Performance of the Genotype? MTBDRPlus assay in the diagnosis of tuberculosis and drug resistance in Samara, Russian Federation
Vladyslav Nikolayevskyy, Yanina Balabanova, Tatyana Simak, Nadezhda Malomanova, Ivan Fedorin, Francis Drobniewski
BMC Clinical Pathology , 2009, DOI: 10.1186/1472-6890-9-2
Abstract: We performed an evaluation of the GenoType? MTBDRplus assay (HAIN Lifescience GmbH, Germany) on a total of 168 sputum specimens from individual patients at a public health laboratory in Central Russia, as a model of a middle income site in a region with high levels of drug resistance. Phenotypic drug resistance tests (DST) were performed on cultures derived from the same sputum specimens using the BACTEC 960 liquid media system.Interpretable GenoType? MTBDRplus results were obtained for 154(91.7%) specimens with readability rates significantly higher in sputum specimens graded 2+ and 3+ compared to 1+ (RR = 1.17 95%CI 1.04–1.32). The sensitivity and specificity of the assay for the detection of rifampicin (RIF) and isoniazid (INH) resistance and MDR was 96.2%, 97.4%, 97.1% and 90.7%, 83.3%, 88.9% respectively. Mutations in codon 531 of the rpoB gene and codon 315 of the katG gene dominated in RIF and INH resistant strains respectively. Disagreements between phenotypical and molecular tests results (12 samples) could be explained by the presence of rare mutations in strains circulating in Russia and simultaneous presence of resistant and sensitive bacilli in sputum specimens (heteroresistance).High sensitivity, short turnaround times and the potential for screening large numbers of specimens rapidly, make the GenoType? MTBDRplus assay suitable as a first-line screening assay for drug resistant TB.Emergence of multidrug resistance tuberculosis (MDRTB, i.e. resistance to at least rifampicin (RIF) and isoniazid (INH) in conjunction with increasing rates of HIV infection worldwide makes the rapid detection of TB drug resistance a key factor in patients' management and care. Rapid (within 1–2 days) diagnosis of MDRTB in clinical specimens allows the commencement of an appropriate TB treatment regimen earlier and helps to prevent transmission of drug resistant TB bacilli.The WHO estimates current MDRTB rates in new and previously treated cases globally at 2.9% and 15.3% re
The Role of the Interferon Gamma Release Assay in Assessing Recent Tuberculosis Transmission in a Hospital Incident
Louise Bradshaw,Elizabeth Davies,Michael Devine,Peter Flanagan,Paul Kelly,Kevin O'Connor,Francis Drobniewski,Vladislav Nikolayevskyy,Ibrahim Abubakar
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0020770
Abstract: In 2007, an extensive contact screening investigation into onward transmission of tuberculosis was instigated at a hospital in Northern Ireland following diagnosis of pulmonary multi-drug resistant TB in a healthcare worker. Interferon gamma release assays (IGRAs) were used to test 333 patients and 98 staff. We investigated for evidence of onward transmission and recent infection based on analysis of clinical, demographic and IGRA data. We also described within-patient variability of IGRA results. Among patients and staff, increasing age of patients was the only factor associated with IGRA positivity. Greatest within-subject variability of IU/mL in serially-tested patients/staff was seen in those with a positive IGRA test and this did not correlate with increased exposure to the index case. IGRA positivity being largely explained by increasing age in patients and previous TB contact in staff lends weight to the conclusion that IGRA positivity reflected previous infection rather than recent transmission.
Survival of Civilian and Prisoner Drug-Sensitive, Multi- and Extensive Drug- Resistant Tuberculosis Cohorts Prospectively Followed in Russia
Yanina Balabanova,Vladyslav Nikolayevskyy,Olga Ignatyeva,Irina Kontsevaya,Clare M. Rutterford,Anastasiya Shakhmistova,Nadezhda Malomanova,Yulia Chinkova,Svetlana Mironova,Ivan Fedorin,Francis A. Drobniewski
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0020531
Abstract: A long-term observational study was conducted in Samara, Russia to assess the survival and risk factors for death of a cohort of non-multidrug resistant tuberculosis (non-MDRTB) and multidrug resistant tuberculosis (MDRTB) civilian and prison patients and a civilian extensive drug-resistant tuberculosis (XDRTB) cohort.
An Integrated Approach to Rapid Diagnosis of Tuberculosis and Multidrug Resistance Using Liquid Culture and Molecular Methods in Russia
Yanina Balabanova, Francis Drobniewski, Vladyslav Nikolayevskyy, Annika Kruuner, Nadezhda Malomanova, Tatyana Simak, Nailya Ilyina, Svetlana Zakharova, Natalya Lebedeva, Heather L. Alexander, Rick O'Brien, Hojoon Sohn, Anastasia Shakhmistova, Ivan Fedorin
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0007129
Abstract: Objective To analyse the feasibility, cost and performance of rapid tuberculosis (TB) molecular and culture systems, in a high multidrug-resistant TB (MDR TB) middle-income region (Samara, Russia) and provide evidence for WHO policy change. Methods Performance and cost evaluation was conducted to compare the BACTEC? MGIT? 960 system for culture and drug susceptibility testing (DST) and molecular systems for TB diagnosis, resistance to isoniazid and rifampin, and MDR TB identification compared to conventional Lowenstein-Jensen culture assays. Findings 698 consecutive patients (2487 sputum samples) with risk factors for drug-resistant tuberculosis were recruited. Overall M. tuberculosis complex culture positivity rates were 31.6% (787/2487) in MGIT and 27.1% (675/2487) in LJ (90.5% and 83.2% for smear-positive specimens). In total, 809 cultures of M. tuberculosis complex were isolated by any method. Median time to detection was 14 days for MGIT and 36 days for LJ (10 and 33 days for smear positive specimens) and indirect DST in MGIT took 9 days compared to 21 days on LJ. There was good concordance between DST on LJ and MGIT (96.8% for rifampin and 95.6% for isoniazid). Both molecular hybridization assay results correlated well with MGIT DST results, although molecular assays generally yielded higher rates of resistance (by approximately 3% for both isoniazid and rifampin). Conclusion With effective planning and logistics, the MGIT 960 and molecular based methodologies can be successfully introduced into a reference laboratory setting in a middle incidence country. High rates of MDR TB in the Russian Federation make the introduction of such assays particularly useful.
A genome wide association study of pulmonary tuberculosis susceptibility in Indonesians
Eileen Png, Bachti Alisjahbana, Edhyana Sahiratmadja, Sangkot Marzuki, Ron Nelwan, Yanina Balabanova, Vladyslav Nikolayevskyy, Francis Drobniewski, Sergey Nejentsev, Iskandar Adnan, Esther van de Vosse, Martin L Hibberd, Reinout van Crevel, Tom HM Ottenhoff, Mark Seielstad
BMC Medical Genetics , 2012, DOI: 10.1186/1471-2350-13-5
Abstract: In stage 1, we used the Affymetrix 100 K SNP GeneChip marker set to genotype 259 Indonesian samples. After quality control filtering, 108 cases and 115 controls were analyzed for association of 95,207 SNPs. In stage 2, we attempted validation of 2,453 SNPs with promising associations from the first stage, in 1,189 individuals from the same Indonesian cohort, and finally in stage 3 we selected 251 SNPs from this stage to test TB association in an independent Caucasian cohort (n = 3,760) from Russia.Our study suggests evidence of association (P = 0.0004-0.0067) for 8 independent loci (nominal significance P < 0.05), which are located within or near the following genes involved in immune signaling: JAG1, DYNLRB2, EBF1, TMEFF2, CCL17, HAUS6, PENK and TXNDC4.Mechanisms of immune defense suggested by some of the identified genes exhibit biological plausibility and may suggest novel pathways involved in the host containment of infection with TB.Tuberculosis (TB) remains one of the leading causes of infection-associated mortality, with close to 10 million new cases and 2 million deaths annually [1,2]. Although Mycobacterium tuberculosis has infected around a third of the world's population, only 3-10% of those infected develop active disease during their lifetime [3]. More than 90% of infected individuals remain asymptomatic with a latent infection. This indicates that host immune/defense pathways are often highly effective in controlling this disease. Because the infection causes such a burden of disease in those unable to contain the infection, it is important to discover underlying mechanisms to aid the development of more effective interventions such as better vaccines and novel treatments for latent and active infection. Similarly, it is important to identify predictive biomarkers that might identify individuals who are most susceptible to developing active TB disease.Studies of heritability using twins and other familial designs have convincingly implicated a genetic
Nonsmooth Optimization Algorithms in Some Problems of Fracture Dynamics  [PDF]
V. V. Zozulya
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.211073
Abstract: Mathematical statement of elastodynamic contact problem for cracked body with considering unilateral restrictions and friction of the crack faces is done in classical and weak forms. Different variational formulations of unilateral contact problems with friction based on boundary variational principle are considered. Nonsmooth optimization algorithms of Udzawa’s type for solution of unilateral contact problem with friction have been developed. Convergence of the proposed algorithms has been studied numerically.
Precessing Ball Solitons as Self-Organizing Systems during a Phase Transition in a Ferromagnet  [PDF]
V. V. Nietz
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.410A3010
Abstract:

Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition is induced by a magnetic field directed along the axis of anisotropy, while the action of the periodic field perpendicular to the main magnetic field has been analyzed. Under these conditions, the characteristics of arising equilibrium PBS are uniquely determined by the frequency of the periodic field, but the solitons with other frequencies are impossible. For such structure, the entropy increase connected with dissipation is compensated by the decrease of the entropy due to the external periodic field. It is shown that the equilibrium PBS are essentially the “self-organizing systems” that can arise spotaneously in a metastable state of ferromagnet.

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