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Biomedical subjects

I K Volkov

Publications and source records attributed to I K Volkov.

At least 19 recordsLinked to original sources
PubMed2004

[Chronic bronchitis in children].

Current approaches to diagnosing in children a group of chronic lung diseases running with the symptoms of chronic bronchitis. Chronic bronchitis is demonstrated to be a major syndrome underlying the clinical manifestations of a number of chronic lung diseases, such as congenital malformations of the lung, chronic pneumonia, ciliary dyskinesia, immunodeficiencies running with the involvement of the lung, cystic fibrosis, etc. The paper shows it necessary to diagnose these conditions, by using various diagnostic studies (bronchological, immunological, biochemical, microbiological, etc.). Primary chronic bronchitis in childhood occurs rarely and it is diagnosed after excluding the above diseases.

Bronchiectasis↗
PubMed2004

[Efficacy of levofloxacin (Tavanic) in the treatment of children with chronic pulmonary diseases].

The efficacy of the fluoroquinolone levofloxacin in the treatment of 35 children with bronchopulmonary disease exacerbation was practically the same as that of amoxycillin/clavulanate, cefotaxime or ceftriaxone. The clinical and bacteriological results were favourable. The eradication of the pathogens responsible for the bronchopulmonary inflammations in 86% of the patients was stated. There is no doubt that fluoroquinolones should not be widely used in pediatrics. They should be considered as reserve drugs for the treatment of severe cases when the routine agents fail. Their use is justified when the situation is risky and the data on the pathogen susceptibility to the drugs are available. Still, levofloxacin is the most safe fluoroquinolone with low hepatotoxicity and lower effect on the central nervous system. The episodes of its negative cardiovascular action are less frequent. Moreover, the most frequent side effects of fluoroquinolones such as nausea, diarrhea or vomiting are less frequent with the use of levofloxacin. No signs of arthropathy in the patients treated with levofloxacin were observed in our trial.

Administration, Oral↗
PubMed2004

[Moraxella catarrhalis in chronic and relapsing respiratory tract infections in children].

Examination of 700 children with chronic and relapsing respiratory tract infections showed that during the period from 1996 to 2003 Moraxella catarrhalis strains were isolated from the sputum of 5.5-9.7% of the patients. The frequency of the emergence was the third after Haemophilus influenzae and Streptococcus pneumoniae. In healthy children M. catarrhalis was isolated in 2.7% of the cases. The most frequent detection of M. catarrhalis was stated in children under 1 year (4.5%). The antibiotic susceptibility tests revealed that the majority of the M. catarrhalis isolates had beta-lactamase activity, were resistant to benzylpenicillin, ampicillin and lincomycin and highly susceptible to amoxycillin/clavulanate, macrolides, certain cephalosporins and levofloxacin. The isolates were most frequent in the patients of the rather severe contingent (congenital lung disease, alveolitis, chronic pneumonia, bronchial asthma). In such patients the bronchoobstructive syndrome was more frequent (46.6%). High frequency of the affection of the upper respiratory tracts in the examined children was stated (62.1%).

Adolescent↗
PubMed1996

[Effect of mutations on the dynamics of numbers of individuals with different genotypes in an isolated heterogeneous population].

The overall (throughout the range) dynamics of the number of diploid individuals possessing n possible gene alleles in a given autosomal locus is studied in an isolated heterogeneous population. The significant influence of new mutations on overall dynamics is shown. It is demonstrated that, under certain conditions, the selection mechanism might have a greater effect on the dynamics of number of individuals with different genotypes in the isolated heterogeneous population than on mutation and "death-reproduction" mechanisms.

Genetic Heterogeneity↗
PubMed1995

[Selection dynamics in a heterogeneous population].

The dynamics of the number of diploid individuals with possible n > or = 2 alleles of a gene located not in a sex chromosome was studied in heterogeneous isolated population. It was demonstrated that if only selection is accounted for, the number of individuals carrying alleles that do not provide maximal selective advantage approaches zero as the time of observation increases, whereas the number of individuals with various genotypes, but with a maximal selective advantage, approaches non-zero stationary values depending on their initial numbers. It was established that under certain conditions and even if processes of death-multiplication are taken into account, the mechanism of selection may have a dominating effect on population dynamics.

Alleles↗
PubMed1994

[Spread of mutations in an inhomogeneous environment with respect to migration. III. A closed model of population dynamics with a arbitrary type of mutation and analysis of the effect of selection mechanisms and "death-reproduction"].

A closed mathematical model of population dynamics for an arbitrary mutant type was developed based on results obtained previously. The model considers the number of individuals with different genotypes, their random and constrained movements across the range, mechanisms of selection and Death-reproduction, and different conditions of the process at range boundaries. The influence of mechanisms of selection and Death-reproduction on integral parameters of the studied process was analyzed.

Death↗
PubMed1993

[The Zivert-Kartagener syndrome in children].

A comprehensive clinicomorphological examination of 24 children with Zivert-Kartagener syndrome ascertained the complete triad (bronchiectasis, maldevelopment of the sinuses and transposition of the viscera) in all of them. Initial signs of the respiratory affection are shown to arise early. The disease progression depended primarily on the scope of pulmonary damage. Electron-microscopic findings at examination of the patients' tracheal mucosa obtained at bronchoscopy revealed reduced number of ciliary cells and abnormal inner structure of the cilia. The impairment in some patients was focal. The attention is drawn to the benefit of early diagnosis and follow-up for such patients who should be treated surgically after careful consideration of potential risks.

Biopsy↗
PubMed1992

[Mathematical modeling of the dynamics of frequency of the mutation process. I. Age features of SA frequency dynamics tendency].

A mathematical method for modelling SA frequency dynamics tendencies, depending on age, for different fixation moments and in general for the whole interval of observation is suggested. The criteria of remainder dispersion attitude is used for choosing an optimal model. The initial hypothesis about discrepancies distribution law is used for checking adequateness of the optimal model to the research process. In addition, aposteriory trust intervals are built for the initial and forecast SA frequency values and the hit into them corresponding the experimental values of SA frequencies is controlled. An example of practical realization of the model proposed is considered and the results obtained analysed.

Models, Theoretical↗
PubMed1991

[The serum and tissue concentrations of antibiotics used in pediatric pulmonology].

Measurements were made of the concentrations of different antibiotics in children with acute and chronic pneumonia. The data obtained do not only confirm the dependence of the peak concentration of the drug in blood serum and tissue fluid on the antibiotic single dose but also point to a direct relationship between the single dose and duration of a high drug concentration in the body. It has been established that parenteral drugs penetrate well the pleural cavity, making it inadvisable to administer antibiotics intrapleurally in the treatment of acute pneumonias complicated by exudative pleurisy. In chronic pneumonia, the maximal content of antibiotic in pulmonary tissue reaches 30% of its serum concentration 2.5-3 hours after a single intramuscular drug injection. Study of the pharmacokinetics of antibiotics administered per os in the treatment of acute pneumonia attests to their rapid absorption from the gastrointestinal tract; as a rule, the peak concentrations were recorded 1 hour after the drug intake and exceeded many times the minimum inhibitory concentration for pneumococci isolated from the patients placed under observation.

Acute Disease↗
PubMed1991

[Experience with using radionuclide methods for evaluation of the lungs and hepatobiliary system in children with allergic diseases].

A total of 25 children with bronchial asthma and 40 children with cutaneous and dermato-respiratory + manifestations of allergy and concomitant injury to the gastrointestinal tract were under observation at an allergological clinic. In addition to the general clinical and allergological examination, radionuclide studies were performed by means of scintipneumography with 99mTc and hepatobiliscintigraphy with 99mTc HIDA. The data obtained indicate that radionuclide methods can be used in childhood allergological practice in the capacity of screening diagnosis as well as in the capacity of adjuvant + methods of examination, making it possible to perform investigations necessary for diagnosis establishment in a more precise and atraumatic manner.

Asthma↗
PubMed1990

[The indices of antipneumococcal immunity in children with chronic pneumonia].

In 76 children with chronic pneumonia the levels of serum antibodies to pneumococcal capsular polysaccharide antigens (serotypes 1, 3, 6B, 8, 9N, 15F, 23F), O-polysaccharide and pneumococcal protein somatic antigens were determined by ELISA techniques. The study showed that in sick children the content of antipneumococcal antibodies in the blood increased with age. No correlation between the content of total immunoglobulins and that of antipneumococcal antibodies in the blood of the patients was established, but a sharp decrease in the concentration of antibodies was registered in a child with hypoglobulinemia. No increase in the level of antibodies to pneumococcal antigens was observed in cases of the exacerbation of Pneumococcus-induced inflammatory process in the lungs.

Adolescent↗
PubMed1988

[Bayesian estimates of unknown parameters of mathematical models of the dynamics of the mutation process and changes in the ratio of cells having passed different numbers of divisions in a culture].

With the help of Bayesian methods, the conditions of solving experimental data samples and their divisions were established, equivalence of estimations of unknown linear dynamic models parameters proved, the estimations having been worked out by both accounting calculation errors and using their compensations with additional noise in the original model's discrete analog. The results are used in mathematical modeling of changing intensity of the process of hereditary pathology frequencies, and the process of changing the ratio of cells having passed different numbers of divisions in the culture.

Bayes Theorem↗
PubMed1988

[Parametric identification of mathematical models of population genetics taking into account the geographical dispersion in finite samples].

A method for parameter identification of population genetics' mathematical models, taking account of geographical disperse at limited samples of experimental data on mutant frequency values has been developed. The existence of the MLS (method of the least squares) estimations of the models' parameters studied has been proved, zero approach of the looked for estimations found and the iterative procedure of making them precise shown. A means of building up the a posteriori function of probability density of the zero and following approximations of the models' parameters is pointed out. The possibility of application of the proposed method to find estimations of mathematical models' parameters of population genetics, taking account of geographical disperse, has been shown on the particular example.

Animals↗