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Biomedical subjects

M Kowalska

Publications and source records attributed to M Kowalska.

At least 37 records · Page 2Linked to original sources
PubMed1994

Relation of nimodipine dose and serum concentration to learning enhancement in aging rabbits.

Nimodipine, a 1,4-dihydropyridine calcium channel blocker, has been shown to enhance learning in aging rats, rabbits, and monkeys. Using an intravenous drug model, the relations among nimodipine dosage, nimodipine plasma concentration, and acquisition rate of the conditioned eyeblink response in aging rabbits were observed. Animals treated with nimodipine reached a behavioral criterion of 80% conditioned responses more quickly than did vehicle-treated control animals. Nimodipine doses produced marked behavioral effects, with statistically significant values starting at 0.5 micrograms/kg/min and reaching maximum efficacy at the minimal dose of 1 microgram/kg/min. Nimodipine at this dose exhibited an effect from the first day of infusion and facilitated learning rate threefold in comparison to control animals. Increasing the nimodipine dose to 3 and 5 micrograms/kg/min did not further facilitate learning rate. As nimodipine doses were augmented, the concentration of the nimodipine in plasma increased in a dose-related fashion. The most effective serum concentration for enhancing learning seemed to be distributed between 10 and 50 ng/ml. Concentrations above 50 ng/ml did not exert a more pronounced effect on the hippocampally dependent trace eyeblink conditioning task. The results of this study suggest that nimodipine may be useful in enhancing learning abilities in aging brain and have established the minimal serum concentration of nimodipine which must be achieved for this effect.

Acoustic Stimulation↗
PubMed1994

[Effect of subinhibitory doses of some antibiotics on bacteria in vitro].

The study was aimed at observation of influence of subinhibitory doses of selected beta-lactam antibiotics (cefuroxime, ceftazidime, thienamycin) and of ciprofloxacin on morphology and physiology of S. aureus and E. coli. The bacteria were subjected to action of these antibiotics in various subinhibitory concentrations in fluid Mueller-Hinton medium at 37 degrees C for 18 hours, and morphological changes in bacterial cells were observed in light and electronic microscope. In case of E. coli changes appeared as presence of elongated forms, while S. aureus formed giant cells with changes in staining. It was found that intensity of these morphological changes was proportional to concentrations of antibiotics. For determination of influence of tested antibiotics on growth of bacteria they were cultured in the fluid Mueller-Hinton medium containing antibiotics in concentrations of 4, 1 1/4 MIC. The culture lasted for 6 hours, and number of bacterial cells in 1 ml of the medium was periodically determined. Distinct inhibition of growth of bacterial cells was proportional to the used concentrations of antibiotics. Described in this paper morphological changes of bacteria found confirmation in change of their physiology expressed as inhibition of bacterial cell growth.

Anti-Bacterial Agents↗
PubMed1993

Functional aspects of calcium-channel modulation.

Associative learning is accompanied by a number of changes in the brain, many mediated by calcium. We have used eyeblink conditioning, a well-controlled learning task in animals and humans, to elucidate these changes. Our studies have focused on the hippocampus, a temporal lobe structure known to be important for storage of new information during learning in mammalian brain. Hippocampal neurons show an enhanced firing rate during learning correlated with behavioral acquisition; they also show reduction in a calcium-mediated after-hyperpolarization (AHP), a likely mechanism for their enhanced activity. Aging animals and humans exhibit learning deficits; aging hippocampal neurons show increased AHPs and altered calcium buffering, which contribute to the behavioral learning deficits. Intravenous administration of the calcium antagonist nimodipine causes aging rabbits to learn the eyeblink conditioning task as quickly as young controls. Oral nimodipine enhances learning rates in aging rabbits, rats, and monkeys. In each case, the type of learning task analyzed is dependent on hippocampal processing for acquisition and is impaired with aging. Nimodipine also reverses aging-related alterations in open field behavior of both rats and rabbits. We have done a series of physiological studies focused on the possible role of nimodipine in enhancing neuronal activity in the hippocampus of aging rabbits. The purpose of these studies was to determine how nimodipine may be functioning at a cellular level to increase the learning rate. Four major conclusions may be drawn from our data: (a) Nimodipine strongly enhanced the firing rate of single hippocampal pyramidal neurons recorded in vivo in an aging- and concentration-dependent fashion. Other calcium-channel blockers, such as nifedipine and flunarizine, given to control for cerebral blood flow changes, had essentially no effect on the hippocampal firing rate. (b) The slow AHP, mediated by an outward calcium-activated potassium current, was markedly larger in pyramidal neurons in hippocampal slices prepared from aging rabbits. Nimodipine, at concentrations as low as 100 nM, reliably reduced the AHPs of aging pyramidal cells. Aging neurons also showed more spike frequency adaptation, or accommodation, than young neurons. Nimodipine partially blocked accommodation at concentrations as low as 10 nM in aging neurons. (c) The calcium action potential was larger in aging neurons. Nimodipine modulated the calcium action potential in an age- and concentration-dependent fashion; concentrations as low as 100 nM reduced the calcium action potential in aging CA1 neurons without effects on young cells. (d) Nimodipine blocked the high threshold, noninactivating calcium current (L-type calcium current) in acutely dissociated hippocampal pyramidal neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

[The effect of tienamycin on selected cellular immunologic parameters in mice during the course of viral-bacterial infections of the respiratory system].

The effect of tienamycin on selected parameters of the immunological system in mice infected with the influenza virus and Staphylococcus aureus was studied. Tienamycin was administered 24 hours, 2 hours prior the infection and 2 hours after the infection (model I), 24 hours and 48 hours after infecting the mice (model II). The authors analysed phagocytosis, bactericidal activity of peritoneal exudate cells and the LIF release induced by the staphylococcus antigen and the viral antigen by the spleen mice leukocytes. The authors found that the antibiotic given to non-infected mice inhibited phagocytosis of staphylococci by the peritoneal exudate cells. In mice that were infected a positive effect of the antibiotic on all studied parameters. Administering the antibiotic before infecting the mice produced an even better effect.

Animals↗
PubMed1989

[Effect of cefoperazone on the activity of selected parameters of cellular immunity in mice with experimental viral-bacterial infection].

We applied mixed, viral-bacterial infections of mice (with influenza virus to the respiratory tract and Staphylococcus aureus) intereperitoneally. We used Sodium Cefoperazone subcutaneously in the dose of 30 mg/kg body weight 24, 48 and 72 hours after the infection. We evaluated phagocytic activity of the granulocytes isolated from animals and bactericidal activity of these cells expressed as their chemiluminescent activity. We studied it on the 3rd, 6th, 9th, and the 14th day after the infection. Phagocytic activity of cells taken from infected mice and treated with the preparation expressed as phagocytic index was the following: 0.38, 0.19; 0.88; 0.99 respectively. In the comparative studies, concerning the effect of preincubation of cells with antibiotic (at the concentration produced in blood serum by therapeutic doses) we found the increase in chemiluminescent process by 57% on the average. Analyzing the preliminary data form the experimental studies on the influence of Cefoperazone on mixed, viral-bacterial infections in mice we found the positive effect of the antibiotic evaluated in some immunological test. Intracellular killing of bacteria is stimulated. Preincubation of granulocytes with the antibiotic gives higher chemiluminescent activity of cells. However, chemotactic and phagocytic activity of cells are not changed.

Animals↗
PubMed1989

Changes in rat lung collagen after life-time treatment with vanadium.

Male Wistar rats were treated in the period from conception up to the 105th day of age with 40 and 60 ppm of vanadium, given as sodium metavanadate in the drinking water. It was found that total collagen and soluble collagen within the lungs of treated animals were significantly lower than in non-treated controls. The decrease in total collagen content observed was not dependent on the dose of vanadium administered. While the content of soluble collagen decreased significantly with increasing dose, the content of insoluble collagen in the lungs of the same rats was significantly higher than in controls and increased with an increase in the dose of vanadium administered. The increase in insoluble collagen was not accompanied by an increased content of hexoses and free aldehydes but by an increased content of collagen-bound vanadium. The results seem to indicate that this metal participates in an increased formation of insoluble collagen by forming additional cross-links between vanadium ions and the ligand groups in the amino acid side-chains.

Administration, Oral↗
PubMed1989

Effect of after-discharge EEG patterns on performance and latency of the conditioned avoidance response in hippocampally kindled cats.

The relation between different EEG after-discharge patterns and memory retrieval of the conditioned avoidance response was studied in 8 hippocampally kindled cats. The after-discharge patterns were classified into 5 basic EEG types. The relation was analyzed in three different situations: A, at the conditioning stimulation onset, B, at the conditioning stimulus termination, and C, when conditioning stimulus onset and termination were studied within the same type of EEG pattern of after-discharge. The moment of presentation of the conditioning stimulus was determined by the type of EEG after-discharge pattern. Significant relation was observed between reflex performance and type II and III EEG AD types. The type II (4.5-12/s spiking activity) was associated with a greater proportion of positive responses if presented on the uniform background of EEG after-discharge patterns. During the type III pattern (EEG dysrhythmia), there were more negative than positive responses in all the three experimental situations, especially if the type III EEG pattern was observed at the time of conditioned stimulus termination. The latency of reflex performance measured in the experimental condition C (the same pattern of EEG during conditioning stimulus onset and termination) was longer during the type II EEG pattern of after-discharges than the latencies found during type III EEG activity and in the control group. During type III pattern associated with greatest proportion of response failures there was, however, no increase of reflex latencies. The results suggest differential effect of different EEG after-discharge patterns on memory retrieval of the well established conditioned avoidance response in cats.

Animals↗
PubMed1989

The effect of Corynebacterium parvum in influenza infected mice.

This paper is the continuation of earlier studies on the effect of the killed suspension of Corynebacterium parvum in influenza virus infected mice. Our investigation showed the normalized effect of these drugs on disturbed function of cell mediated immunity during experimental influenza infection especially in phagocytic and bactericidal activity of granulocytes. The present experiments concern the explanation of these infection mechanisms. Intraperitoneal injection of Corynebacterium parvum stimulated spleen index. Foot pad test is higher than in comparatively treated BCG group. The pathomorphological analysis of the spleen, thymus and peritoneal lymph nodes points out to the multiplication of multiple lymph nodes sinus cells. Generally, C. parvum possessed protective effect in experimental influenza infection. We tested the following parameters: phagocytic and bactericidal activity of granulocytes, liberation of leukocytes migration inhibition factor (LIF).

Adjuvants, Immunologic↗
PubMed1988

The effect of vanadium on lung collagen content and composition in two successive generations of rats.

Lung collagen content in rats continuously exposed for two generations to 20 ppm vanadium as sodium metavanadate drinking solution was quantified by measurement of hydroxyproline in hydrolysates of whole lungs. The content of soluble and insoluble collagen isolated from the lungs of the same treated rats was also quantified by the same means. It was found that the content and composition of lung collagen for both F1 term fetuses and 21-day-old F1 pups of the treated group did not differ from the results obtained for control rats of the same age. However, total collagen and soluble collagen within lungs of adult F1 rats and F2 term fetuses were significantly lower than in non-treated controls, while the content of insoluble lung collagen of the same rats was significantly higher.

Animals↗
PubMed1987

Effect of physical exercise on some parameters of immunity in conditioned sportsmen.

The studies were performed on 20 conditioned cyclists and 19 untrained men. At rest absolute and percent number of neutrophils, eosinophils, and monocytes, neutrophil bactericidal activity, and blood plasma beta-glucuronidase, acid phosphatase, and lactic dehydrogenase (LDH) activities were similar in sportsmen and untrained men, while neutrophil adherence was lowered in sportsmen. Maximal physical exercise induced significant rises in absolute numbers of neutrophils and monocytes in both groups. In sportsmen, adherence of neutrophils and monocytes and neutrophil bactericidal activity significantly decreased under the influence of exercise, while neutrophil phagocytic activity did not change. On the other hand, in untrained men, maximal physical exercise did not induce significant changes in neutrophil and monocyte adherence and bactericidal activity of neutrophils, but their phagocytic activity increased. Blood plasma beta-glucuronidase, acid phosphatase, and LDH activities increased during exercise in both groups. The changes observed tended to normalize during 2-h recovery. The results obtained suggest that intensive physical exercise tends to depress nonspecific immunity, which may render sportsmen more susceptible to infections.

Adolescent↗
PubMed1987

Cell phenomena in experimental viral-bacterial infections in mice. I. The release of leukocyte inhibiting factor (LIF) from mouse spleen leukocytes in the presence of specific antigens.

The aim of the presented experiments was to estimate LIF production in the course of experimental infections with influenza viruses (of different degrees of adaptation), with S. aureus 209P and in the course of simultaneous viral-bacterial infections in mice. Spleen cells incubated with specific influenza antigens obtained according to Nath's method were used for the experiments as well as cells incubated with staphylococcal staphylolysine (Boehring Werke). The interdependence between LIF release and the degree of adaptation of viruses to lung tissue was observed. When influenza viruses APR-8 of high degree of adaptation to animal lung tissue were used, inconsiderable LIF production was observed in the early stage of observation. When the animals were infected with viruses A/Scotland/74 of low degree of adaptation, significant LIF production could be noticed since the 1st day of observation. Mixed, viral-bacterial infections influenced insignificantly LIF release. Its production was mainly conditioned by influenza viruses used for the infections.

Adaptation, Physiological↗
PubMed1987

Cell phenomena in experimental viral-bacterial infections in mice. II. Phagocytic activity of granulocytes during infection with influenza viruses and staphylococci.

In the paper the influence of viral, bacterial and mixed viral-bacterial infections on phagocytic activity of mouse peritoneal granulocytes was estimated. Granulocytes isolated on the 3rd, 6th, 9th and 14th day of infection were incubated for 1 h at 37 degrees C together with S. aureus 209P cultivated in the presence of 14C labelled glucose. The radioactivity of samples was measured in the scintillatory counter. The results were shown as phagocytic index of granulocytes. The obtained data point to the decrease of granulocyte phagocytic activity in mice infected with bacteria in the first period of infection. When mice were infected with non-adapted influenza virus the decrease of granulocyte phagocytic activity was observed in the late stage of infection. The infection with adapted virus as well as mixed infection led to the complete disfunction of granulocyte phagocytic activity.

Adaptation, Physiological↗
PubMed1987

Cell phenomena in experimental viral-bacterial infections in mice. III. Estimation of the phagocytic activity of peritoneal granulocytes after in vitro contact with viral and bacterial antigens.

In the paper, the influence of in vitro contact of granulocytes with the antigen obtained from A/Scotland/74 and APR-8 influenza viruses as well as with staphylococcal anatoxine on phagocytic activity of granulocytes was examined. The results are given as phagocytic indices. In the group of animals infected with non-adapted influenza viruses the increase of phagocytosis was observed only in the first period of infection (on the 3rd and 6th day), whereas phagocytic index of granulocytes obtained from animals infected with adapted virus increased only on the 3rd day. In mixed infections, when granulocytes were contacted in vitro with viral as well as bacterial antigens, the insignificant increase of phagocytic indices was observed in the initial period of infection. On the other days of observation (on the 6th, 9th and 14th day) the obtained results approximated to values of phagocytic indices of granulocytes from the control group of animals.

Adaptation, Physiological↗
PubMed1987

Cell phenomena in experimental viral-bacterial infections in mice. IV. Bactericidal activity of peritoneal granulocytes in experimental viral and viral-bacterial infections.

Bactericidal activity of mouse peritoneal granulocytes was examined on the 3rd, 6th, 9th and 14th day after infection. 18-hour-old S. aureus 209P culture was used for examination. Human serum of AB group was used for opsonization. The mixture of bacteria, leukocytes and serum was placed at 37 degrees C for 2 h. Every 30 minutes the samples were taken to estimate the total number of living bacteria and the number of live intracellular bacteria. In the group of animals infected with bacteria as well as in the animals infected with non-adapted influenza viruses, granulocytes showed increased intracellular killing of test bacteria. The decrease of bactericidal activity of granulocytes was observed when they were taken from mice infected with adapted influenza viruses. In mixed infections, with the use of non-adapted virus and bacteria, the decrease of bactericidal activity of granulocytes was observed on the 6th and 9th day after infection. In the group of animals infected simultaneously with non-adapted virus and bacteria, increased bactericidal activity of granulocytes was observed in the initial period of infection. At the same time, on the 14th day this ability significantly decreased.

Animals↗