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Biomedical subjects

A V Lobanov

Publications and source records attributed to A V Lobanov.

At least 19 recordsLinked to original sources
PubMed2004

Effect of cholinergic and adrenergic receptor blockade on arrhythmogenic activity of endothelin-1 during inhibition of nitric oxide synthesis in awake mice.

We studied the effects of blockade of nicotinic receptors in sympathetic and parasympathetic ganglia (hexamethonium), muscarinic receptors (atropine), and beta1-adrenoceptors (atenolol) on arrhythmogenic activity of endothelin-1 during inhibition of nitric oxide synthesis with Nomega-nitro-L-arginine in NMRI mice. Atropine reduced, while hexamethonium completely abolished the arrhythmogenic effect of endothelin-1 during nitric oxide synthase inhibition. Atenolol potentiated arrhythmogenic activity of Nomega-nitro-L-arginine, but endothelin-1 had no effect on the incidence of arrhythmias under these conditions.

Adrenergic Antagonists↗
PubMed2003

Arrhythmogenic effects of endothelin-1 under conditions of NO-synthase blockade with L-NAME in NMRI mice.

Arrythmogenic effects of endothelin-1 were studied in NMRI mice under conditions of NO-synthase blockade with N omega-nitro-L-arginine methyl ester. Intravenous injection of endothelin-1 increased heart rate variability in awake mice. NO-synthase blockade potentiated the arrythmogenic effects of endothelin-1. In narcotized animals the arrythmogenic effect of endothelin-1 was not observed and was considerably weakened under conditions of NO-synthase blockade. Arrhythmia was paralleled by atrioventricular block and lengthening of the ST segment.

Animals↗
PubMed2001

Selenium metabolism in Drosophila: selenoproteins, selenoprotein mRNA expression, fertility, and mortality.

Selenocysteine is a rare amino acid in protein that is encoded by UGA with the requirement of a downstream mRNA stem-loop structure, the selenocysteine insertion sequence element. To detect selenoproteins in Drosophila, the entire genome was analyzed with a novel program that searches for selenocysteine insertion sequence elements, followed by selenoprotein gene signature analyses. This computational screen and subsequent metabolic labeling with (75)Se and characterization of selenoprotein mRNA expression resulted in identification of three selenoproteins: selenophosphate synthetase 2 and novel G-rich and BthD selenoproteins that had no homology to known proteins. To assess a biological role for these proteins, a simple chemically defined medium that supports growth of adult Drosophila and requires selenium supplementation for optimal survival was devised. Flies survived on this medium supplemented with 10(-8) to 10(-6) m selenium or on the commonly used yeast-based complete medium at about twice the rate as those on a medium without selenium or with >10(-6) m selenium. This effect correlated with changes in selenoprotein mRNA expression. The number of eggs laid by Drosophila was reduced approximately in half in the chemically defined medium compared with the same medium supplemented with selenium. The data provide evidence that dietary selenium deficiency shortens, while supplementation of the diet with selenium normalizes the Drosophila life span by a process that may involve the newly identified selenoproteins.

Algorithms↗
PubMed2001

Analysis of ethanol-glucose mixtures by two microbial sensors: application of chemometrics and artificial neural networks for data processing.

Although biosensors based on whole microbial cells have many advantages in terms of convenience, cost and durability, a major limitation of these sensors is often their inability to distinguish between different substrates of interest. This paper demonstrates that it is possible to use sensors entirely based upon whole microbial cells to selectively measure ethanol and glucose in mixtures. Amperometric sensors were constructed using immobilized cells of either Gluconobacter oxydans or Pichia methanolica. The bacterial cells of G. oxydans were sensitive to both substrates, while the yeast cells of P. methanolica oxidized only ethanol. Using chemometric principles of polynomial approximation, data from both of these sensors were processed to provide accurate estimates of glucose and ethanol over a concentration range of 1.0-8.0 mM (coefficients of determination, R(2)=0.99 for ethanol and 0.98 for glucose). When data were processed using an artificial neural network, glucose and ethanol were accurately estimated over a range of 1.0-10.0 mM (R(2)=0.99 for both substrates). The described methodology extends the sphere of utility for microbial sensors.

Biosensing Techniques↗
PubMed1998

Detection of ethanol in a two-component glucose/ethanol mixture using a nonselective microbial sensor and a glucose enzyme electrode.

Chemometric theory was applied to a microbial sensor for determinations of ethanol in the presence of glucose. Microbial sensors, consisting of Gluconobacter oxydans cells immobilized on Clark-type amperometric oxygen electrodes, exhibited good sensitivity but low selectivity toward ethanol and glucose. An Eksan-G commercial glucose analyzer was used as a second sensor for multivariate calibration and analyses. Microbial sensors exhibited nearly complete additivity for total glucose plus ethanol concentrations from 0.0 to 0.6 mM. Within this linear range, chemometric analyses provided estimates of ethanol concentration with measurement errors of less than 8%. Multivariate calibration thus is a promising approach to enhance the usefulness of microbial sensors.

Acetobacteraceae↗
PubMed1997

[A method for a modified Billroth II-Braun gastric resection].

A modified method of resection of the stomach after Billroth-II was used in treatment of 26 patients with ulcer disease of the stomach and duodenum and with antral cancer of the stomach. During this procedure the following anastomoses were formed: frontal-colonic, frontal, superior, longitudinal-transversal and antiperistaltic side-to-side anastomosis with interintestinal anastomosis after Braun [correction of Brown] following the dissection of the Treitz ligament. One complication was noted--the incompetent duodenum stump. There were no lethal complications.

Anastomosis, Surgical↗
PubMed1989

[A cluster sampling method and possibility of using it for mass screening of rickettsial infections].

Cluster sample technique has become a standard methodology for evaluation of immunization coverage and assessment of morbidity and mortality due to vaccine preventable and diarrhoeal diseases. The method is based on obtaining data in 30 randomly selected clusters and considered a statistically justified and economical alternative to the simple random sample approach. Cluster sample technique seems a relevant methodology for seroepidemiological studies and other surveys conducted as a part of surveillance of Rickettsial diseases.

Cluster Analysis↗
PubMed1986

[The cluster method in conducting epidemiological research].

The Expanded Programme on Immunization (EPI) whose goal is to reduce morbidity and mortality by providing children with immunizations against diphtheria, pertussis, tetanus, poliomyelitis, measles, and tuberculosis continually faces the problem of documenting immunization coverage rates. Therefore the EPI seeks simple, effective, and inexpensive methods of evaluation which could be implemented in different countries. An example of such a method is a simplified cluster sampling technique of estimation of immunization coverage through the examination of 210 children, selected randomly as 30 groups of 7 children each. In 1978-1984 more than 1000 immunization coverage surveys were performed all over the world, mainly in developing countries. In a modified way this method is also used to collect data on morbidity and mortality of certain EPI target diseases as well as diarrhoeal diseases.

Child↗
PubMed1978

[Detection of antibodies to Rickketsia prowazekii by using the antigen neutralization test].

The authors studied a possibility of using the antigen neutralization test with dry immunoglobulin typhus erythrocytic diagnostic agent for the purpose of detection of Rickettsia prowazeki antibodies. Blood sera of 315 healthy persons, 24 patients with sporadic typhus, and 18 laboratory animals immunized with R. sibirica and R. burneti, as well as with Proteus OX19 were examined. The results obtained pointed to the high specificity and sensitivity of the given serological test. A possibility of its use for antibody detection both in the typhus patients and in persons who sustained this infection in the past was demonstrated. In difference from the complement fixation test it permits to study anticomplementary sera.

Antibodies, Bacterial↗