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Biomedical subjects

E V Frolova

Publications and source records attributed to E V Frolova.

At least 19 recordsLinked to original sources
PubMed2006

[Immunological aspects of pathogenesis of stomatological constructional materials intolerance].

In blood and the mixed saliva of patients with intolerance of stomatologic constructional materials the maintenance of cytokines, factors of humoral answer were investigated. It was established, that in formation of intolerance the increased sensitivity stomatologic constructional materials which is not connected to allergic reaction of immediate type and is, apparently, pseudoallergic or develops on other type. There is an activation of the local immune answer including local synthesis of proinflammatory cytokines, sIgA and hyperactivation of complement system to formation of C3a component. Toxic and allergic action of stomatologic constructional materials grows in patients having antibodies to Candida albicans in the mixed saliva.

Adult↗
PubMed2004

[Efficacy of nondrug correction of hypertension in general medical practice].

Effectiveness of nondrug correction of elevated blood pressure was assessed in a group of hypertensives selected from participants of a study of prevalence of cardiovascular risk factors conducted in one of Saint Petersburg districts. Patients were divided into 3 subgroups in which the following interventions were used: diet with decreased sodium content, aerobic physical exercise, or combination of these methods. Blood pressure lowering achieved with these methods (-11 mm Hg systolic and -6.8 mm Hg diastolic) was maintained throughout 2 years of observation.

Adolescent↗
PubMed2003

Effect of carotid operations on regression of motor disorders in patients with a history of ischemic stroke.

This paper is concerned with an evaluation of the clinical effect of reconstructions on the brachiocephalic vessels in patients who suffered ischemic stroke. Altogether 143 patients with the above pathology were operated on. Of these, mild hemiparesis was present in 72 patients, moderate hemiparesis in 49, and severe hemiparesis was recognized in 17 subjects. The postoperative lethality accounted for 1.4% (2 subjects). Intraoperative development of repeated stroke was ascertained in three more subjects. The follow up of the operated patients lasted from three months to two years. In the postoperative period, a study was made of the time course of changes in motor pyramidal deficit. The study allowed the conclusion to be drawn that reconstructions on the brachiocephalic vessels are not only of preventive importance but also favour the elimination of motor disorders in patients who suffered ischemic stroke.

Brachiocephalic Trunk↗
PubMed2000

Anion permeability and erythrocyte swelling.

Permeability of cell membranes to cations may increase as a result of membrane oxidation or in certain pathologies. We studied the effects of nonselective increases in cell membrane permeability to univalent cations on the volume of erythrocytes incubated in phosphate-buffered saline (PBS) using amphotericin B (5-10 mg/l suspension) or gramicidin D (10-100 microg/l suspension) as the membrane permeabilizing agents. Both antibiotics caused K+ to leak, Na+ to accumulate intracellularly, and cell volume to increase. The interval needed to reach the equilibrium between the intracellular and extracellular ion concentrations ranged from 30 min to several hours, depending on the antibiotic concentration. In spite of a rapid disappearance of cation transmembrane gradients, cell volume increased relatively slow. Even 24 h after the membrane permeability was changed, the volume of most erythrocytes did not increase to the lytic values (about 1.6 times the normal volume). The slow increase in erythrocyte volume was accounted for by slow changes in the transmembrane Cl- gradient. 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), a specific inhibitor of anion transport, while producing no effect on the transmembrane Na+ and K+ fluxes induced by the antibiotics, significantly inhibited the decrease in the transmembrane Cl- gradient and the increase in erythrocyte volume. Analysis of these data by means of mathematical modeling showed that it failed to satisfactorily describe the experimental kinetics of erythrocyte swelling in response to increases in the membrane permeability to univalent cations if its permeability to Cl was set to be constant. The satisfactory description of this kinetics could be achieved by assuming that the membrane permeability to anions decreased with increasing erythrocyte volume. The results obtained demonstrate that transmembrane anion transport may be considered to be a component of the mechanism responsible for the erythrocyte volume stabilization, because a significant decrease in the swelling rate allows the erythrocytes with damaged membranes to activate a relatively slow (metabolic) mechanisms of cell volume stabilization and/or repair their damaged membranes.

Amphotericin B↗
PubMed2000

[Structural characteristics of ionotropic glutamate receptors revealed by channel blockade].

The topography of the channel binding site in glutamate receptors (AMPA and NMDA types of rat brain neurons, receptors of molluscan neurons and insect muscle), and in two subtypes of nicotinic cholinoreceptors (in frog muscle and cat sympathetic ganglion), has been investigated by comparison of the blocking effects of mono- and dicationic derivatives of adamantane and phenylcyclohexyl. The channels studied can be divided into two groups. The first one includes AMPA receptor and glutamate receptors of mollusc and insect, and is characterised by the absence of activity of monocationic drugs and the strong dependence of dicationic once on the internitrogen distance in the drug molecule. The second group includes NMDA receptor and both nicotinic cholinoreceptors. Contrary, here the blocking potency of monocations and dications are practically equal irrespective of molecule length. The data obtained suggest that hydrophobic and nucleophilic components of the binding site are located close to each other in the channels of the NMDA receptor type but are separated by approximately 10 A in the AMPA receptor channel.

Adamantane↗
PubMed1999

[The efficacy of Neovir in the combined treatment of patients with operable tumors of the gastrointestinal tract].

Under observation there were 32 patients with operable tumors of the gastro-intestinal tract. The average age of the patients was (64.8 +/- 7.5) years. Patients of the control group (18 patients were given the routine complex treatment. The main group (14 patients) were additionally given the interferonogenic immunomodulator "Neovir" which resulted in lower risk of the appearance of pyo-septic complications. It was confirmed by positive dynamics of the indices of cellular immunity, intensified production of proinflammatory cytokines and interferon-alpha.

Acridines↗
PubMed1997

[Free-radical processes in blood serum, liver and large bowel during 1,2-dimethylhydrazine-induced carcinogenesis in rats].

Rats were injected 21 mg/kg dimethylhydrazine (DMH), in a single dose, subcutaneously (experimental run I), or 5 times at weekly intervals (experimental run II) to measure free-radical process indices in blood serum, liver and large bowel 24 hr after a single exposure and 6 months after 5 exposures. Run I identified marked DMH inhibition of blood-serum level of active forms of oxygen (AFO). However it did not involve any changes in the concentrations of such products of lipids peroxidation (LP) as dien conjugates, Schiff's bases and protein peroxides (PP). Neither did total antioxidation activity (TAA) or that of Cu, Zn-superoxydismutase (SOD) change. However, nitrite levels increased while those of ceruloplasmin decreased significantly. AFO levels also dropped in the liver, following a single injection of DMH, with TAA and SOD activity decreased significantly. No changes were observed in AFO generation processes in the bowel which was targeted by DMH treatment. A slight decrease in TAA, a rise in PP and diverse changes in the enzymatic system of antioxodation protection were recorded: decreased SOD activity and an insignificant rise in catalase level (like in the liver). Run II showed an intensification of peroxidation in blood serum and bowel in animals bearing intestinal tumors. However, no distinct changes occurred in the liver. The results point to a tendency of free-radical processes being intensified during DMH-induced carcinogenesis in rats.

1,2-Dimethylhydrazine↗
PubMed1991

[Kinetics of work of ion channels operated by nicotinic cholinoreceptors in the membrane of mollusk neurons].

The patch-clamp technique in cell-attached configuration was applied to investigate suberyldicholine-induced currents in Planorbarius corneus neurons. The single channels currents registered as inward ones at hyperpolarization of the patches were due to chloride ions efflux from the cell. Suberyldicholine (5 mumol/l) was added into the patch electrode. Usually there were more than one channel in the membrane fragment under the clamp control. The open and closed times, bursts and clusters' lengths were measured and histograms of single-channel parameters were obtained. Histograms were approximated by a sum of exponentials. Single exponentials were fitted to open times; to = 27 +/- 3 ms (n = 21). Histograms of closed times were fitted by three exponentials: tc1 = 9.5 +/- 1.0 ms (n = 21)--short gaps; tc2 = 171 +/- 33 ms (n = 19)--intermediate gaps: tc3 = 5.2 +/- 1.0 s (n = 21)--long gaps. The openings were grouped in bursts: tb2 = 203 +/- 23 ms (n = 10) and in clusters of bursts: tk3 = 1.5 +/- 0.5 s (n = 9). There were some evidences that the single burst was the result of opening, closing and reopening of just the same channel. A kinetic model with one open and three nonconducting states is plausible for single-channel data. Two long-lasting closed times may be associated with desensitization states of the receptor-channel complex. Estimates of the kinetic model parameters were obtained, that may be useful in the further study of a mode of action for cholinergic drugs in Planorbarius corneus neurons.

Animals↗
PubMed1990

[Chlorine channels activated by suberyldicholine in mollusk neurons].

Patch-clamp technique in cell-attached configuration was applied to investigate ion permeability induced by suberyldicholine in the neurons of freshwater mollusc Planorbarius corneus. The inward currents through single channels were registered at patch potentials 50-100 mV more negative than resting potential of the cell. When the patch pipette contained suberyldicholine (5 mol/l), single channel currents were recorded which grouped in bursts and bursts of openings could themselves be grouped together in clusters of bursts. The desensitisation was not too pronounced: usually we were able to observe single-channel currents for 20-30 minutes. The unit conductance gamma was found to be about 10 pS.

Animals↗
PubMed1990

[Delayed hypersensitivity to Candida albicans].

Conditions and factors influencing the formation of delayed hypersensitivity (DH) to yeast-like fungi of the species C. albicans under experimental conditions have been studied. The intensity of this reaction has been found to depend on the dose and method used for infecting mice, the time of the test and the qualitative state of fungal cells. As the result of this study, the infectious model of DH to C. albicans has been proposed. This model may be used for the study of the influence of different exogenous and endogenous factors of cell-mediated immune response to candidiasis.

Animals↗
PubMed1989

[Photo-induced destruction of DOPA-melanin].

Studies of the effect of illumination at different wavelengths revealed a high stability of DOPA-melanin to the visible light. Contrariwise, UV-visible light of high intensity upon prolonged (many hours) illumination caused a significant bleaching of the diluted aqueous solution of the pigment. The absorption spectrum of DOPA-melanin in the UV- and IR-regions did not differ from the initial one; however, the illuminated pigment acquired an ability for fluorescence. Stepwise gel chromatography on Toyopearl-55 and Toyopearl-40 columns resulted in three fractions of photobleached DOPA-melanin which differed in their molecular masses, absorption spectra (UV, IR) and fluorescence. It was concluded that the photoinduced bleaching of DOPA-melanin was mainly due to the pigment depolymerization. A possible mechanism of melanin photodestruction is discussed.

Chromatography, Gel↗
PubMedDate not supplied

Structural characteristics of ionotropic glutamate receptors as identified by channel blockade.

The channels of four types of ionotropic glutamate receptor (NMDA receptors and Ca-permeable AMPA receptors of rat brain neurons, and cation-selective receptors from mollusk neurons and insect postsynaptic muscle membranes) and two subtypes of nicotinic cholinoreceptor (from frog neuromuscular junctions and cat sympathetic ganglia) were studied. The structural characteristics of channels determining their susceptibility to blockade by organic mono- and dications were identified. These studies used homologous series of adamantane and phenylcyclohexyl derivatives. These experiments showed that the receptors studied here could be divided into two groups. The first group included the AMPA receptor and the mollusk and insect receptors. These were characterized by the lack of effect on the part of monocations and a strong relationship between the activity of dications and the distance between nitrogen atoms. The second group included the NMDA receptor and both subtypes of the nicotinic cholinoreceptor (muscular and neuronal). Here, conversely, the activity of monocations and dications, regardless of their lengths, were essentially identical. A model for the binding sites of blockers in channels is proposed, which takes these observations into account.

Animals↗
PubMedDate not supplied

An application of an effective interdisciplinary health-focused cross-cultural collaboration.

The phenomenon of cross-cultural collaboration is not new. What is lacking in the literature, however, is a discussion of how health professionals from various cultures, collaborating together, have addressed their patients' health care needs to improve their quality of life. Because of increased interest in global health issues, it seems logical that health professionals from various countries form collaborative partnerships to investigate and address these health issues. Although treatments to health problems are offered, it is not generally communicated in the literature how cross-cultural collaboration played a role in managing the process to solve the problem. By applying the concepts for global managers outlined by P. R. Harris and R. T. Moran (1996), this article describes how the investigators established a successful cross-cultural collaboration for conducting health research between teams in the United States and Russia.

Communication↗