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Biomedical subjects

L I Ivanova

Publications and source records attributed to L I Ivanova.

At least 19 recordsLinked to original sources
PubMed2004

[Relation between resistance to oxidation and cholesterol acceptance of high density lipoproteins in patients with ischemic heart disease].

Cholesterol (CH) acceptance ability of high density lipoproteins (HDL) was assessed in 43 ischemic heart disease (IHD) patients, including patients with post-infarction cardiosclerosis and class II-III effort angina. CH acceptance ability of HDL was measured as increment of HDL CH after incubation with artificial CH-containing system. Oxidabilities of HDL and total plasma were estimated by quantitation of lipid peroxidation products (hydroperoxides and thiobarbituric acid-reactive substances - TBARS) after incubation with Cu(2+) ions. HDL fraction (after apo B lipoproteins removal) of IHD patients appeared to include 2 times less additive CH compared with donor's HDL despite lower (-12%) HDL CH level. Negative correlation (r =-0.38, p<0.05) existed between formed TBARS in HDL and HDL CH acceptance. In total plasma of IHD patients elevation of both formed TBARS and particularly hydroperoxides was observed. Parallelism between decrease of CH acceptance by HDL, oxidability of HDL and of total plasma testifies on weakness not only of CH-accepting, but also of antioxidant HDL functions in IHD patients.

Cholesterol↗
PubMed2004

[The way of evaluation of cholesterol accepting capacity of plasma high density lipoproteins].

The simple way of quantitative evaluation of high density lipoproteins (HDL) capacity to absorb additive cholesterol quantity is proposed. It allows to evaluate indirectly intensity of the first, rate limiting stage of reverse cholesterol transport its accepting from the cells by means of HDL. The way includes the usage of stable artificial cholesterol donor--cholesterol covered inert polymer particles, which are than more convenient, than cell culture use. The total HDL rough fraction (i.e. serum after apoB lipoproteins removal) was shown to include more than 50% cholesterol in addition to yet presenting amount. But this ability is sharply reduced, or sometimes even is completely absent, in HDL of 63 coronary heart disease (CHD) patients (as compared with 41 healthy donors). This difference of potential cholesterol accepting capacity is revealed even at the same initial HDL concentrations. The negative correlation (r = - 0.32, p < 0.05) between this HDL property (delta HDL cholesterol) and their oxidability in the ions Cu2+ presence was observed. This underlines atherogenic role of HDL oxidability. The treatment of patients by phospholipids (as Lipostabyl) resulted to recovery of HDL cholesterol accepting capacity. The possible mechanisms of junction of this HDL activity with their oxidability are discussed, as well as necessity of evaluation of HDL properties and reverse cholesterol transport for the choice of care strategy of CHD patients.

Blood Chemical Analysis↗
PubMed2001

[Blood bacteriostatic activity in patients with respiratory tuberculosis].

Vertical diffusion on the Löwenstein-Jensen medium was used to study blood bacteriostatic activity (BBA) in 174 patients with respiratory tuberculosis in relation to the drug resistance of isolated Mycobacterium tuberculosis (MT) strains and to the course of a tuberculous process. There was a clear relationship of BBA to the sensitivity of MT cultures to isoniazid: BAC was high and moderate in 90.8-98.2% of cases if strain drug sensitivity was present and low or null in 98% with drug resistance. The high and medium values of BBA correlated with the clinical indices "improvement" and "significant improvement". Patients with zero and lower values of BBA and isoniazid resistance showed a progressive specific process in 22.0% of cases. Estimation of total BBA by using liquid media is the most informative method.

Antitubercular Agents↗
PubMed1993

[An analysis of the mechanism of the resistance to barbiturate action by using exogenous RNA].

For the first time the experimental method of exogenous RNA has been used to evaluate the role of protein synthesis in different organs for the development of resistance to the soporific effect of barbiturates. Liver cytosolic RNA of phenobarbital-treated donors was found to reproduce completely the effect of phenobarbital-induced resistance to barbiturates in recipient rats: the reduction of hexenal-induced sleep and the increase of cytochrome P450 content in hepatic microsomes. Brain and renal RNAs had no influence on recipients. These data demonstrate the decisive role of microsomal R450-contained enzymes synthesis in the mechanism of the development of barbiturate resistance. It is concluded that exogenous RNA technique is of value for the organ-specific analysis of various complicated biological phenomena resulted from the activation of protein synthesis. The mechanism of exogenous RNA action and the possibility of cellular interactions by means of RNA molecules are also discussed.

Animals↗
PubMed1992

[Beta-adrenoblockers in the reorganizing of the food center of the hypothalamus under the influence of substance P].

An ability of substance P (15 nmol intracerebroventricularly) to transform functional properties of the hypothalamic feeding center manifested in escape reaction in response to threshold electrical stimulation of this motivation center in rabbits. Beta-adrenergic antagonists inderal and obsidan (0.25, 0.5 mg, respectively) injected intravenously were found to restore feeding elicited by electrostimulation of the hypothalamic feeding center. However, escape reaction, elicited from the feeding center under substance P was found unchanged after intravenous administration of 0.25 mg kalipsol. The data obtained suggested an important role of beta-adrenergic mechanisms in substance P transformation of the functional properties of the hypothalamic feeding centre.

Adrenergic beta-Antagonists↗
PubMed1992

[Substance P and the resistance of biological motivations to ethanol].

Ability of the substance P to enhance the tolerance of feeding and defence motivations of ethanol was studied in rabbits. Ethanol led to disintegration of central mechanisms of both feeding and escape responses elicited by a threshold electrical stimulation of lateral and ventromedial hypothalamic centres. Subsequent i.v. administration of the substance P restored the effects of midbrain RF on the motivational centres. The inhibitory effect of the dorsal hippocampus and the facilitatory effect of the midbrain RF on excitability of the lateral hypothalamus, are also restored. The data obtained suggest that the substance P is able to increase a tolerance of the central mechanisms of biological motivations of ethanol.

Animals↗
PubMed1991

[Clinical and hygienic aspects of the effect of antimony ore on workers in the Far North].

The clinical and hygienic studies performed at the antimonite ore extraction mines in Yakutia revealed that the workers were exposed to high concentrations of polymetallic dusts, containing chromium dioxide, antimony, arsenic and their compounds. 11% of the workers exhibited dust bronchitis, changes in the blood and immune reactivity indices which were due to reactions of adaptation to the Far North climatic conditions and the occupational factors' toxic effects.

Air Pollutants, Occupational↗
PubMed1991

[Enhancement of the resistance of the escape reaction to ethanol after substance P].

An ability of substance P (30 micrograms/kg intravenously) to prevent deleterious effects of ethanol (E) (0.5 g/kg intravenously) on central mechanisms of escape reaction elicited by threshold electrical stimulation of the ventromedial hypothalamus was investigated in chronic experiments upon rabbits. Substance P was found to prevent E effects on excitability of the ventromedial hypothalamus (VMH) and on facilitatory influences of the midbrain reticular formation on this emotional centre which were observed in intact animals. Inhibitory effects of the dorsal hippocampus on the VMH could not be evaluated due to its alterations in response to previous substance P administration. The authors suggest that substance P can be considered to be a possible endogenous factor to increase a tolerance of emotional behavioural reactions of an organism to alcohol.

Animals↗
PubMed1991

[The etiopathogenesis of poisonings by the components of technical fluids].

The studies of peculiarities of aliphatic alcohol metabolism in etiopathogenesis of acute poisoning with methyl alcohol and ethilenglicol have shown that it was reasonable to apply the inhibitors of alcoholdehydrogenase as a specific antidote in emergency therapy. Inhibitors prevent the formation of toxic products by blocking metabolism of these spirits.

Acute Disease↗
PubMed1989

Substance P against ethanol-induced alterations in central mechanisms of feeding and escape in rabbits.

Rabbits were treated with 0.5 g/kg ethanol intravenously and alterations of limbic-midbrain interactions in both feeding and escape elicited by threshold electrical stimulation of the lateral (LH) and ventromedial hypothalamus (VMH) were observed. Decrease of the VMH excitability and abolishing of inhibitory effects of the dorsal hippocampus (HPC) and facilitatory influences of the midbrain reticular formation (MRF) on both motivational hypothalamic centres were found in animals after ethanol administration. Subsequent single injection of substance P (SP) (30 microgram-kg i.v.) just at the height of alcohol manifestations in central mechanisms of feeding and escape led to restoration of the VMH excitability and facilitatory MRF influences on this motivational centre. SP administration was also found to restore the inhibitory hippocampal and facilitatory MRF effects on the excitability of the LH feeding centre. Partial and selective SP restoration of ethanol-induced alterations in feeding and escape which are observed in the present study, as well as the data of some other researchers, led to the suggestion that peptides could be used as factors of enhancing tolerance to ethanol or curing deleterious acute alcohol-induced effects in motivated behaviours in animals.

Animals↗
PubMed1988

[Substance P and effects of ethanol on the central mechanisms of the escape reaction in rabbits].

Substance P (SP) effects on the central mechanisms of escape reaction, elicited by threshold electrical stimulation of the ventromedial hypothalamus were investigated in rabbits pretreated with ethanol (0.5 g/kg). SP (30 micrograms/kg) was demonstrated to normalize in 71.4% of cases the excitability of the ventromedial hypothalamus which was decreased by ethanol and restored in 83.3% of cases the facilitatory effects of the midbrain reticular formation in escape reactions. However, SP was ineffective in the restoration of the inhibitory effects of the dorsal hippocamp on the excitability of the ventromedial hypothalamus that was obvious in intact animals. Partial normalizing effect of SP on escape reaction in rabbits after previous ethanol administration can be accounted for by the fact that both undecapeptide and ethanol are similar in their realization of central effects such as an interaction with the same brain neurotransmitters, interference with neuronal enzyme processes and reactions with opiate receptors.

Animals↗
PubMed1987

[Effect of monooxygenase reactions catalyzed by cytochrome P-450 on the microsomal membrane].

Hydroxylation of dimethylaniline in rabbit liver microsomes is accompanied by inactivation of cytochrome P-450 and the formation of products inhibiting the catalytic activity of non-inactivated cytochrome P-450. Other enzymes and electron carriers of microsomal membrane (cytochrome b5, NADH-ferricyanide reductase, NADPH-cytochrome c and NADPH-cytochrome P-450 reductases) as well as glucose-6-phosphatase were not inactivated in the course of the monooxygenase reactions. Phospholipids and microsomal membrane proteins were also unaffected thereby. Consequently, the changes in the microsomal membrane during cytochrome P-450 dependent monooxygenase system functioning are confined to the inactivation of cytochrome P-450.

Aniline Compounds↗
PubMed1985

[Substance P in the central mechanisms of the escape reaction].

The role of substance P in the central mechanisms of escape reaction elicited by electrical stimulation of the ventromedial hypothalamus was investigated in chronic experiments on rabbits. Intravenous injection of substance P (30 micrograms/kg) led to a short-term (less than 10 min) increase in the threshold of stimulation of the ventromedial hypothalamus and to more stable (up to 1.5 h) disorders of the hippocampal-hypothalamic relations. After substance P injection the inhibitory effects of the dorsal hippocampus but not the facilitating influences of the midbrain reticular formation on excitability of the hypothalamic motivation center were found to be lacking. Disorders of the central mechanisms of escape reaction after substance P injection correlated with new patterns of the main EEG rhythms in different areas of the brain cortex in response to the ascending excitations of the limbic-midbrain structures. Interpreting the mechanisms of substance P involvement in escape reaction the authors point to the ability of the given peptide to interact with different transmitter systems of the brain and opiate receptors and to alter the brain blood circulation.

Animals↗
PubMed1984

[Substance P in the central mechanism of the rabbit feeding response evoked by stimulation of the lateral hypothalamus].

The effects of substance P on the central mechanisms of food motivation elicited by electrical stimulation of the lateral hypothalamus were studied in chronic experiments on rabbits. Intravenous injection of substance P (30 micrograms/kg) brought about a dramatic reduction in the excitability of the "food center" in the hypothalamus, which returned to normal 45-60 minutes after injection. Higher concentrations of substance P provoked food behavior inversion up to the replacement of food motivation by avoidance behavior. Intravenous injections of substance P disturbed the relationships between the hippocamp, midbrain reticular formation and hypothalamus seen in health. This manifested in complete cessation of the inhibitory effects of the dorsal hippocamp and facilitating influences of the midbrain reticular formation on the excitability of the hypothalamic "food center". It is assumed that disorders of the central mechanisms of food motivation may arise from the effects produced by substance P directly on the central nervous system or on the brain via changes in the hormonal balance and responses of the autonomous nervous system.

Animals↗