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Biomedical subjects

D Witkowska

Publications and source records attributed to D Witkowska.

At least 37 records · Page 2Linked to original sources
PubMed1992

The study of leucine and methionine transport in the gut of rats intoxicated with thiram.

The effects of thiram on amino acids transport in rats jejunum were investigated. Using the gut everted sac method it was shown that 4 weeks intoxication with the pesticide (5% DL50 per os daily) caused time dependent inhibition in transport of C14-leucine and C14-methionine in the rat jejunum. In order to obtain further information, the influx of both amino acids into the jejunum slices was investigated in rats treated with thiram for 2 weeks. Over a range of amino acid concentrations (0-20 mM) the influx of these compounds was defined as the sum of a saturable term (active transport) and a linear term (passive transport). It was shown that thiram affected only the active transport of amino acids. The analysis of this transport for leucine using Lineweaver-Burk plots showed a decrease of the half-saturation constant (Kt), while the maximal value (Jm) remained unchanged. In the methionine transport study both kinetic constants were changed.

Animals↗
PubMed1992

Studies on immunity in mice immunized with outer membrane proteins of Hafnia.

Nonspecific protection induced in mice after administration outer membrane proteins of Hafnia alvei against infection with homologous and heterologous bacteria was transferred into other mice with lymphocytes isolated from spleens of mice immunized with outer membrane proteins. It was also found that mice sensitized with outer membrane proteins derived from H. alvei or with living bacteria induced in animals delayed hypersensitivity (DTH) in homologous and heterologous systems. The observed type of hypersensitivity was transferable to normal mice by lymphocytes obtained from donor animals which were previously sensitized with OMP. The experiments revealed that immunity induced with outer membrane proteins of Hafnia alvei is cell-mediated.

Animals↗
PubMed1992

Some biological properties of outer membrane proteins of Hafnia.

Outer membrane proteins (OMP) isolated from four antigenically different strains of Hafnia alvei were tested for the toxicity, pyrogenicity, ability to induce Shwartzman reaction as well as for their influence on the leukocyte system. LD50 doses for the studied preparations determined on inbred mice were 18, 20, 28 and 34 mg/kg. These differences in the toxicity of the preparations were reflected in manifestation of Shwartzman reaction; more toxic preparations induced strongest necrohemorrhagic changes at the site of injection. The OMP preparations injected intravenously to rabbits caused moderate increase of body temperature. They induced changes in the number of leukocytes in the animals comparable with those of other preparates of bacterial origin.

Animals↗
PubMed1992

Effect of outer membrane proteins from Shigella on humoral immunity induced in mice by SRBC.

Shigella flexneri outer membrane proteins (OMP) which had been earlier found to exert immunomodulatory effect on cell mediated immune response were also found to act as immunomodulator of the humoral immune response. Effects of OMP were investigated in the experiments in vitro and in vivo, where the level of humoral immune response, measured as the number of plaque-forming cells (PFC) to SRBC in the spleen was evaluated. We demonstrate that small doses of OMP (1-5 micrograms) stimulate, whereas higher doses (10-50 micrograms) suppress the humoral immunity.

Adjuvants, Immunologic↗
PubMed1992

Fraction of spleen cells responsible for suppression of cellular immune response to SRBC in mice treated with outer membrane proteins of Shigella.

Effect of splenocytes isolated from mice immunized with suppressive dose of OMP from Shigella on delayed hypersensitivity, induced in mice with sheep red blood cells was investigated. Only the population of T lymphocytes was found to suppress the delayed hypersensitivity, as measured by the footpad reaction. The results suggest that OMP of Shigella are able to induce in the spleens of animals active T cells which are responsible for the suppression of cellular response induced by SRBC.

Animals↗
PubMed1992

Humoral response in mice immunized with outer membrane proteins of Hafnia alvei. Protective activity of anti-OMP-antibodies.

Intraperitoneal immunization of mice with outer membrane proteins (OMP) of Hafnia alvei induced in the animals a synthesis of specific antibodies. The antibody levels, determined by ELISA test, were found to be relatively low in the sera of mice immunized with a single dose (5 micrograms) of OMP and after a second immunization. However, they were higher in mice immunized with three doses of OMP. The antibodies were present in circulation for a relatively short time after immunization. Serum containing anti-OMP antibodies given intraperitoneally to normal mice protected them only against challenge with a homologous Hafnia strain.

Animals↗
PubMed1991

[Study of combined effects of mixtures of pesticides from various chemical groups on calcium absorption in the rat intestine. I. Dichlorvos and thiram].

Investigation was made of the effect of many-times repeated treatment with single pesticides: tiuram and dichlorfos (administered in a daily dose corresponding to 5% of LD50), and with their mixture, on calcium uptake by rat duodenum sections. Calcium uptake was examined by the method of Papworth and Patrick, as modified by the present authors. The amount of calcium transported by the sections was determined by the liquid scintillation method. Total transport was expressed in microM Ca2+/g tissue/h; subsequently, the participation of active and passive transport in total transport was determined. It was shown that administration of DDVP to rats during 14 days caused disturbances in active absorption of calcium, manifesting themselves by a significant decrease in the constant Jm (maximal transport rate) and in the constant Kt, this pointing to a rise of calcium affinity to the carrier. The effect of DDVP on passive transport was only slight. Under the same experimental conditions tiuram exerted an effect on both active and passive calcium transport. It caused a drop in the constant Jm and Kt (active transport), and to inhibition of passive transport. According to statistical treatment of the results, the effect of both pesticides combined on active transport does not differ from the effect of DDVP itself. Thus, the differences in diffusion probably result from the action of tiuram.

Animals↗
PubMed1991

[Studies on the combined effect of pesticide mixtures belonging to different chemical groups on calcium absorption in rat intestine. Part II. Chlorfenvinphos and cypermethrin].

In male Wistar rats study was made of the effect of multiple treatment (14 days) with single pesticides (chlorfenvinphos and cypermethrin) and with their mixture on intestinal calcium absorption. Pesticides were administered intragastrically through a stomach tube in a daily dose corresponding to 5% of LD50; in the case of the pesticide mixture, 5% of LD50 of each component were administered. Calcium uptake (active and passive) by duodenal sections were determined by the method of Papworth and Patrick, modified by the present authors. It was found that under the applied experimental conditions chlorfenvinphos influences the active transport of calcium, causing an increase in the values of the constants Jm (maximal transport rate) and Kt (affinity of calcium to carrier), whereas it inhibits the passive transport. Similar changes were displayed by rats exposed to cypermethrin. On the other hand, combined administration of both pesticides led to a lack of changes in the efficiency of active transport and to impairment of passive transport, as compared with control.

Animals↗
PubMed1990

Structural studies on Hafnia alvei 114-60 O-antigen.

The structure of Hafnia alvei 114-60 O-antigen has been established using sugar and methylation analyses as well as 1H-NMR spectroscopy. The results obtained proved that the repeating unit of Hafnia alvei 114-60 O-antigen is identical to that of Hafnia alvei ATCC 13337 standard strain and has the following structure: [formula: see text]

Antigens, Bacterial↗
PubMed1990

Studies on nonspecific protection induced with OMP of Shigella flexneri and other genera of Enterobacteriaceae.

Outer membrane proteins (OMP) isolated from Shigella flexneri, Escherichia coli, Proteus vulgaris and Salmonella typhimurium were tested for their protective activity. Each OMP preparate given to mice intraperitoneally in a single injection (5 micrograms/per mouse) protected the animals not only in homologous but also in varying intensity in heterologous systems. Evidence was obtained that this nonspecific protection is cell mediated.

Animals↗
PubMed1990

Immunogenic and protective properties of outer membrane proteins of Hafnia alvei.

Outer membrane proteins (OMP) extracted from antigenically distinct or related strains of Hafnia alvei containing defined composition of major proteins proved to be immunogenic. Intraperitoneal immunization of mice with a single dose of such preparations protected the animals against homologous and heterologous Hafnia strains. The OMP preparations were also found to induce protection with varying intensity against Escherichia, Proteus, Shigella and Salmonella.

Animals↗
PubMed1989

The effect of zinc and magnesium on calcium uptake into the rat duodenum slices.

The experiments were carried out on 80 male Wistar rats, divided into four groups as follows: group 1, treated orally with ZnCl2 at a dose of 10 mg Zn2+/kg for 14 days; group 2, control; group 3, MgCl2-treated at a dose of 5 mg Mg2+/kg; group 4, treated with ZnCl2 plus MgCl2 in the same manner as groups 1 and 3. The influx of calcium into the rat duodenum slices was investigated in vitro by the method of Papworth and Patrick. Over a range of calcium concentrations (0-10 mM) the influx of this element was defined as a sum of a saturable term (active transport) and a linear term dependent on concentration (passive transport). In the zinc-treated rats only the saturable term was affected. The study of this term by Lineweaver-Burk plots showed a decrease of the half-saturation constant, Kt, while the maximal value, Jm, remained unchanged. Moreover, magnesium was shown to interact with zinc at gut level because simultaneous oral administration of Mg2+ and Zn2+ to rats protected them against the inhibition of calcium uptake observed when Zn2+ was given alone.

Analysis of Variance↗
PubMed1989

The effect of Trichoderma viride C-1 UV mutagenization on cellulases activity.

Trichoderma viride C-1 strain was irradiated with UV until the survival level of 0.03% was obtained. Sixteen mutants were isolated on the basis of the visible clearance zone around the colonies on the media with cellulose and glycerol. Then they were cultivated on a rotary shaker in the liquid Saunders medium supplemented with microcrystalline cellulose and comminuted sugar beet pulp. Exo-1,4-beta-glucanase, endo-1,4-beta-glucanase and beta-glucosidase were assayed in the supernatants of postcultural liquids at different time intervals of culture. The same mutants were characterized by higher biosynthesis level of exoglucanase (1.2-5.0 times) endoglucanase (1.2-2.5 times) and beta-glucosidase (1.5-1.7 times) when compared with the wild type strain.

Cellulase↗
PubMed1988

Hafnia alvei lipopolysaccharides: isolation, sugar composition and SDS-PAGE analysis.

Lipopolysaccharides (LPS) of 33 strains of Hafnia alvei were isolated and purified. LPS content of the dry bacterial mass ranged from 1.2 to 4.5%. All examined lipopolysaccharides contained glucose, glucosamine, heptose, 3-deoxy-octulosonic acid and often galactose. Rhamnose, mannose, galactosamine, mannosamine and unidentified amino sugars were found in some H. alvei strains. Sialic acid was present in LPS of one strain. D-3-Hydroxybutyryl groups also were identified in lipopolysaccharides of 5 strains of this genus. SDS-PAGE of the lipopolysaccharides was presented in the paper. According to these results two core types exist in H. alvei.

Carbohydrates↗
PubMed1988

Phagocytic and bactericidal properties of macrophages of mice immunized with outer membrane proteins (OMP) of Shigella.

Macrophages obtained from peritoneal exudates of mice immunized with the single doses (1 and 5 micrograms) of OMP were shown to have stronger phagocytic as well as bactericidal properties in relation to Shigella flexneri bacilli than nonactivated macrophages. Macrophages from the animals immunized with 10, 20 and 30 micrograms OMP doses showed phagocytic and bactericidal properties similar to those of nonactivated macrophages while the immunization with the dose 50 micrograms resulted in their suppression. Likewise, activity of macrophages from mice immunized twice or three times with various doses of OMP did not differ much from that obtained after immunization with single OMP doses. On the other hand, immunization of mice with a sublethal dose of live Shigella flexneri did not activate either phagocytic or bactericidal properties of macrophages. Besides, phagocytic and bactericidal activity of macrophages of mice immunized with OMP of Shigella was determined in relation to Salmonella typhimurium. The doses 1 and 5 micrograms of OMP resulted in slight activation of macrophages which manifested itself by a little increase in their phagocytic and bactericidal ability. When used in the dose 10 micrograms, OMP remained without any effect on the above activity of macrophages. Only the dose 50 micrograms, slightly suppressed their phagocytic properties.

Animals↗
PubMed1988

Outer membrane protein composition of Hafnia alvei.

The outer membrane proteins (OMP) obtained from 33 strains of Hafnia of different origin, were analysed by SDS-polyacrylamide gel electrophoresis. About 21 protein bands could be distinguished in OMP of each strain. The major proteins of the outer membrane were of apparent molecular weight 34.000 (34K), 37.000 (37K), 39.000 (39K) and 41.000 (41K). On the basis of the electrophoregrams obtained, four groups of strains possessing different composition of major OMP were distinguished: (1) 34K and 37K, (2) 34K, 37K and 39K, (3) 34K, 37K and 41K, (4) 34K, 39K and 41K. The major OMP of 34K present in all strains examined was susceptible to proteolytic enzymes and was found to be heat modifiable. The remaining major OMP of 37K, 39K and 41K were identified as peptidoglycan associated proteins.

Bacterial Proteins↗
PubMed1987

Hypersensitivity to Shigella outer membrane proteins in mice.

Mice sensitized with living Sh. flexneri 3a or with outer membrane proteins (OMP) derived from these bacteria showed Arthus and delayed type hypersensitivity (DTH) when injected in the footpad with OMP. The delayed reactivity to OMP was transferable to normal mice by spleen cells obtained from donor animals which were previously sensitized with living bacteria.

Animals↗