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Biomedical subjects

I R Dorozhkova

Publications and source records attributed to I R Dorozhkova.

At least 19 recordsLinked to original sources
PubMed2005

[Analysis of risk factors of the occurrence of drug resistance in patients with tuberculosis from civil and penitentiary sectors in the Samara Region].

The true prevalence rates of multidrug-resistant tuberculosis (MDRT) are unknown for most regions of Russia. This study was conducted in the Samara Region that differs from other regions in the rapid spread of HIV infection. The purpose of this study was to determine the primary and acquired resistance of Mycobacterium tuberculosis (MBT) to first-line antituberculous drugs in patients from civil and penitentiary sectors and to reveal risk factors of drug resistance of MBT. Six hundred patients (309 civilians and 291 prisoners who had been bacteriologically diagnosed as having tuberculosis. The authors have established the following:--in new cases, primary drug resistance is as follows: to isoniazid [38.9% (95% CI, 31.3-36.9%)], to rifampicin [25.9% (95% CI, 19.4-33.4%)] and to MDRT [23.0% (95% CI, 16.7-30.3%)];--in prisoners, the primary resistance of MBT was statistically more significant than in civilians;--male sex, in adequate prior or current treatment for tuberculosis for more than 4 weeks, the presence of fibrocavernous tuberculosis and previous prison stay are essential risk factors of the development of resistance of MBT to both any first-line drug and MDRT;--HIV infection is unassociated with resistance.

Adult↗
PubMed2005

[The composition and drug sensitivity of a mycobacterial population in patients with suspected tuberculosis].

By using the diagnostic material (175 sputum samples and 103 bronchoalveolar lavage fluid samples) taken from 39 patients with suspected tuberculous infection during a 2.5-month follow-up, the authors traced the time course of changes in the composition and drug sensitivity of a mycobacterial population to rifampicin. Along with the traditional microbiological studies, the latest molecular biological studies, a TB-BIOCHIP test system (enzyme immunoassay) in particular, were employed to detect the bacterial and L-transformed forms of the causative agent. A molecular biological assay was first developed to detect the drug sensitivity of L-forms of Mycobacterium tuberculosis.

Antibiotics, Antitubercular↗
PubMed2004

[New technologies in the determination of drug susceptibility in Mycobacterium tuberculosis].

A variety of mutations in the genes rpoB, katG, inhA, ahpC, kasA was studied by using different molecular biological methods (conformational polymorphism of single-chain fragments, heteroduplex analysis, biochips) in rifampicin- and isoniazid-resistant Mycobacterium tuberculosis (MBT) strains isolated from patients with pulmonary tuberculosis. Twenty-nine mutation combinations were identified in the MBT strains. The use of biochips is the most promising method for identifying the type of mutations responsible for the simultaneous resistance to rifampicin and isoniazid. Detection of several MBT strains in one patient requires the use a combination of molecular biological and microbiological studies.

Antitubercular Agents↗
PubMed2001

[Components of monitoring drug resistance of tuberculosis agent in the evaluation of effectiveness of the national tuberculosis control program].

The authors analyzed the changes and pattern of drug-resistance in tuberculosis pathogen by using the reports of over 700 microbiological laboratories of tuberculosis control service in Russia in the past 20 years (1979-1998), which yielded a monitoring system for drug resistance in the pathogen in this country. Seven underlying informational blocks were identified. These included more than 20 different quantitative and qualitative parameters covering the characteristics of a patient and the pathogen and regionally environmental and epidemiological indices. Analysis of the data on the united northern, west-northern, and Baltic regions is given as an example of successful use of the monitoring system.

Antibiotics, Antitubercular↗
PubMed2000

[The monitoring of the drug resistance of the causative agent of tuberculosis in Russia in 1979-1998].

The Russian 1979-1998 annual reports of the centralized microbiology laboratories of the tuberculosis controlling service were used to examine the pattern and trends of formation of drug-resistance in the tuberculosis pathogen. The data on over 1.2 million cases of drug resistance to 7 antituberculous drugs were pooled. The analysis indicated that drug resistance had increased in two steps in the past 2 decades. The maximum levels of the drug resistance of Mycobacterium tuberculosis to some drugs were limited (7.8 and 37.2%), which are not greater those as indicated by the international statistics.

Antitubercular Agents↗
PubMed1999

Drug-resistant strains of Mycobacterium tuberculosis isolated in Russia.

SETTING: State Research Center for Applied Microbiology, Russian Research Institute of Phthisiopulmonology (Ministry of Health, Moscow). OBJECTIVE: To analyze drug-resistant clinical isolates of Mycobacterium tuberculosis obtained from patients referred to the institute from different parts of Russia, and to study the mechanisms of their rifampicin resistance. DESIGN: Fifty clinical isolates of M. tuberculosis were analysed. Polymerase chain reaction (PCR) and sequencing were used to study the mechanisms of rifampicin resistance in 25 isolates. RESULTS: Among cultures isolated from 50 patients, drug resistance was detected in 33. Most of the isolates were resistant to rifampicin (25 isolates), isoniazid (14 isolates), and streptomycin (seven isolates). Only 6% of the isolates were resistant to one drug, while 14% were resistant to two, 32% to three, 40% to four, and 8% to five drugs. Susceptible isolates were derived from 17 patients. The following point mutations and deletions in the rpoB locus, responsible for high level rifampicin resistance (more than 50 microg/ml in egg-based medium), were detected: G-->A/395 (Arg-->Gln), C-->T/232 (His-->Tyr), C-->T/221 (Ser-->Leu), G-->T/202 (Asp-->Tyr), GA-->TT/202-203 (Asp-->Phe), deltaATGGACCAG/199-207 (Met, Asp, Gin), A-->T/91 (Met-->Leu), TG-->CC/227-228 (Leu-->Ser), GAG-->AGT/349-350-351 (Gln-->Ser), deltaGGG/354(Gly). CONCLUSION: A number of previously unrecognised genetic modifications in the rpoB region were found in rifampicin-resistant strains isolated from patients from different parts of Russia.

Adult↗
PubMed1996

[Biological characteristics of mycobacterial agent in homeless patients with pulmonary tuberculosis].

133 homeless subjects with pulmonary tuberculosis were examined microbiologically in Moscow Tuberculosis Hospital N 7 in 1993-1994. In most of the examinees the disease was advanced with destruction and intensive bacterial discharge (100-10,000 microbes in the sample). New-onset cases discharged mycobacteria with multiple drug resistance. Acquired drug resistance was registered in 83.8% of previously treated patients, 73% of them had resistance to 2-6 drugs. Isoniazid-, rifampicin- and streptomycin- resistant were 48.6, 33.8 and 63.5% of the examinees, respectively.

Adult↗
PubMed1995

[L-transformation of mycobacteria in the light of current epidemiological situation of tuberculosis in the world].

To determine a role of L-forms of Mycobacterium tuberculosis in the development of a recurrent tuberculous process in persons with residual pulmonary tuberculous changes, a total of 2,412 persons registered at a dispensary as those included into Groups VIIA and VIIB who were found to have a significant tuberculosis infection pool. The tuberculosis pathogen was detected in 214 (9%) examinees in the bacterial and L forms. A further follow-up of the persons whose pathological material had shown the L form which are prone to reverse indicated that the isolation of unstable mycobacterial L forms is an important predictive sign showing the high potential hazard of tuberculous process reactivation.

Adult↗
PubMed1994

[Tissue immunity reactions in experimental aspergillosis].

The authors have developed a model of acute and chronic aspergillosis induced by Aspergillus fungi injected intraperitoneally to white mice. Subsequent histological evaluation of the mouse viscera identified 3 phases of tissue immunity reactions: non-specific, characterized by mucosal epithelial proliferation and hypersecretion, lymphoid reaction and development of diffuse alveolitis in the lungs, rapid growth of aspergilla; specific, characterized by pronounced proliferative processes, onset of lymphoid-histiocytic and macrophagal pneumonia, emergence of small thin-wall intraalveolar micetomas, absence of aspergilla growth from homogenates of the internal organs; productive, characterized by formation of granuloma, large aspergillomas in the liver and mesenterium. The course of experimental aspergillosis reflects the process of immunity formation in response to advancing infection.

Animals↗
PubMed1993

[Characteristics of biological properties of the causative agent in patients with pulmonary tuberculosis exposed to prolonged low-dose radiation].

Strains of M. tuberculosis isolated from tuberculous patients exposed to low-dose radiation after the Chernobyl accident were compared to those obtained from tuberculous non-irradiated controls for L-forms incidence, L-transformation and virulence. A total of 31 cultures were examined in vivo. In response to L-transforming preparations the frequency and rate of L-forms induction in the test strains were much higher than those in the controls. The same tendency was registered for virulence.

Animals↗
PubMed1992

[Estimation of the degree of risk of reactivation of residual tuberculous changes based on the status of mycobacterial population].

The study was undertaken to define the role of L-forms of M. tuberculosis having different qualitative and ++quantitative characteristics in the development of recurrences of a tuberculosis process in subjects with residual tuberculous changes in the lungs. The microbiological and ++clinico-roentgenological+ examination included 2412 subjects who were in VIIA and VIIB Dispensary Groups. These subjects were found to have a considerable reservoir of tuberculosis infection: the causative agent of tuberculosis in the bacterial and L-forms was detected in 214 (9%) of the examinees. Detection of M. tuberculosis L-forms tended to reversion in a pathological material of subjects with residual tuberculous changes in the lungs is a major predictors of high potential risk of tuberculosis process reactivation.

Adult↗
PubMed1991

[Pathomorphological assessment of the therapeutic effect of mycobacteriophages in tuberculosis].

The effect of DS6A mycophage was studied in comparison with that of isoniazid on 30 guinea pigs with disseminated tuberculous infection in order to reveal the therapeutic effect of the mycobacteriophage and tissue reactions caused by it. The mycophage was found to have therapeutic properties in disseminated tuberculosis in guinea pigs but its action is less pronounced than in isoniazid monotherapy. Study of the special features of tissue reactions in mycophage monotherapy has demonstrated that with the mycophage phagocytosis remains incomplete and granulomatous processes that gradually lose morphological signs of tuberculous inflammation and acquire typical features of sarcoidosis develop in the animal organs.

Animals↗
PubMed1990

[Characteristics of qualitative changes in the Mycobacteria population during the treatment of middle-aged and elderly patients with newly detected pulmonary tuberculosis].

Clinicobacteriological investigations were applied to 142 new cases of pulmonary tuberculosis at the age of 60 to 89 years. The control group consisted of 132 patients of young and middle ages (from 17 to 40 years). The form of the process, its extent and the character of the destructions in them were the same as those in the elderly and senile patients. It was shown that the pathogen bacterial forms in the elderly and senile patients were much more frequent than L-forms of M. tuberculosis (67.6 and 42.9 per cent, respectively). The tubercle bacilli were mainly isolated from pure cultures (45.8 per cent). L-transformants of M. tuberculosis in the elderly and senile patients were markedly less frequent than in the patients of the control group (69.7 per cent) with analogous forms of tuberculosis. The frequency of L-forms and their rapid reversion into the initial bacterial form of M. tuberculosis (28.0 per cent) and the same period of isolating both the bacterial and L-forms were the distinctive features of the L-forms isolated from the elderly and senile patients. It was suggested that L-forms of M. tuberculosis played an important role in reactivation of the specific process.

Age Factors↗