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Biomedical subjects

A Hostacká

Publications and source records attributed to A Hostacká.

At least 91 records · Page 5Linked to original sources
PubMed1987

Partial purification and biological activity of the enterotoxic component of Pseudomonas aeruginosa.

From an Pseudomonas aeruginosa strain isolated from feces of a patient with clinical manifestation of diarrhoeal disease a filtrate from the culture in proteose peptone broth was prepared. After concentration, the culture filtrate was separated on Sephadex G-100 column in four fractions. The first high molecular fraction (F1) represented components of relative molecular mass exceeding 100,000, the second fraction those about 58,000, the third fraction those about 23,000 and the fourth one was composed from low molecular components of molecular mass lower than 10,000. In biological tests, the most marked reactions were caused by the third fraction. It caused a fluid accumulation in the rabbit ileal loop test, reactions in the rapid and delayed skin tests and in the mouse foot edema test. Besides these activities the third fraction caused also a hemolytic, proteolytic and elastase activity. A clear cytotoxic effect of this fraction was seen on Vero, Y1 and CHO cell lines. It was also found, that after heating (100 degrees C/10 min) both, the enterotoxic and hemolytic activities were lost.

Animals↗
PubMed1985

Toxic exoproducts of citrobacter freundii.

A strain of Citrobacter freundii isolated from the feces of a patient with diarrhoea was examined for growth kinetics and toxic exoproduct formation using the complete (BHI) and synthetic culture media. It was found that the test organism in synthetic medium grew distinctly slower than in BHI. Fractionations on Sephadex G-100 column yielded 3 fractions from the complete medium culture filtrate and 2 fractions from the culture filtrate obtained from synthetic medium. The first culture filtrate fractions (F1) were represented by components of the molecular weight over 100,000, the respective second fractions (F2) from complete and synthetic medium were of the molecular weights of about 40,000 and 10,000. In the early skin test on rabbits the toxicity of culture filtrates and their fractions manifested itself by an increased permeability of blood vessels, in the late skin test by a hemorrhagic reaction associated with dilatation of blood vessels and induration of the skin tissue. In a test on mouse foot pad all separated filtrate fractions gave a positive edematous reaction. In cultured Vero cells samples of synthetic medium fractions gave a distinct cytotoxic reaction. Immunochemically, the presence of LPS in culture filtrates as well as some variations in the antigenicity of components from the complete and synthetic medium fractions were found. Apart from LPS some additional high-molecular-weight components were also present in the toxic complex of both first filtrate fractions (F1). Much more attention should be given to analysis of these first fraction complexes as well as to toxinogenicity of second fractions (F2) using some additional tests.

Bacterial Toxins↗
PubMed1984

Toxinogenic potential of Proteus mirabilis strains.

Live bacterial suspensions, original as well as concentrated filtrates of Proteus mirabilis cultures caused positive reaction in the rapid skin test (vascular permeability reaction) and also in the delayed test (combination of haemorrhagic reaction, dilatation of vessels and induration) as well as in the test of mice-foot edema. The test on suckling mice did not prove the presence of thermostable enterotoxin. After separating the concentrated culture filtrates the biologic activity appeared in fraction 1 (relative molecular mass over 100 000) concerning the delayed skin test and in the fraction 2 (relative molecular mass approx. 40 000) in the rapid skin test. The activity localized in the fraction 1 can be ascribed to a lipopolysaccharide. The fraction 2 with an expressed activity in the rapid skin test showed also cytotoxic and proteolytic activity. In both fractions the presence of active antigen substances with different mobility and different antigen specificity was demonstrated.

Animals↗
PubMed1983

Biological activities of enterotoxin from Vibrio cholerae non-01.

The specific antiserum 54(2) prepared in rabbits by combined intraperitoneal and intravenous immunization with the enterotoxin from Vibrio cholerae non-01 was found to neutralize the enterotoxin biologic activity expressed by rabbit skin vascular permeability and hemorrhage factors. The inhibition of biologic activity was also observed when using antiserum to choleragen, but choleragen could not be neutralized by specific serum 54(2). The enterotoxin was also inactivated when heated at 100 degrees C for 10 min, but heating at 56 degrees C for 30 min had no influence on its biologic activity. The enterotoxin from Vibrio cholerae non-01 was found to elevate concentration levels of cAMP in the epithelial cells of the rabbit intestine and this elevation was comparable with that produced by the filtrate of Vibrio cholerae 569 B culture. The culture filtrate from Vibrio cholerae non-01 exhibited a similar activity. The Vibrio cholerae non-01 enterotoxin as well as the original culture filtrate were found to be cytotoxic for Vero cells.

Adenylyl Cyclases↗
PubMed1982

Toxic factors of Aeromonas hydrophila and Plesiomonas shigelloides.

In detail, exoproducts of Aeromonas hydrophila and Plesiomonas shigelloides were studied on the pathogenesis of diarrhoea. Enterotoxin, hemolysin and a cytotoxic factor were found in a fraction of culture filtrates of Aeromonas hydrophila with a molecular weight of approximatley 60,000. Apart there from a cytotoxic factor was also found in a fraction with molecular weight above 100,000. This fraction contained also endotoxin which was hemolytic, too. Enterotoxic activity was expressed by an accumulation of fluid in the ligated ileal loop and by increased vascular permeability in the skin of rabbit. Activation of adenylate cyclase was not found. Cytotoxic activity was represented by hemorrhagic reaction in the skin of rabbit, in some cases by sanguinous and mucous fluid in the ligated ileal loop and by significant morphological alterations on Vero cells leading to the death of cells. Culture filtrates of Plesiomonas shigelloides show only very low activity in biological experiments. Separation and purification steps led to a more concentrated and active material.

Aeromonas↗
PubMed1977

Partial purification and characterization of the NAG vibrio enterotoxin.

The culture filtrates of non-cholera vibrios (NAG vibrios) which possessed toxic activity were concentrated, precipitated with (NH4)2SO4 and fractionated on a column of Sephadex G-100. Three fractions were obtained. The first fraction contained mainly lipopolysaccharide which possessed no enterotoxic activity measured by the fluid accumulation in the ligated rabbit ileal loop as well as no activity in the skin permeability test. However, it was toxic for mice after i.v. administration (LD50: 600 microgram per mouse). The second fraction contained one antigenic protein and revealed four bands in the region of albumin migration distance in polyacrylamide electrophoresis. The size of the molecules from the second fraction was estimated by the elution volume from the G-100 Sephadex and polyacrylamide electrophoresis at approximately 50,000-70,000 daltons. This fraction had marked proteolytic activity. The third fraction contained proteins. In biological experiments only the second fraction possessed the enterotoxic activity identical to that of the original filtrate. The coexistence of the permeability and hemorrhagic factor in this material was proven by means of the rabbit skin test and a fast toxic effect for infant mice after intragastric inoculation. The enterotoxic activity characteristic of cholera enterotoxin was demonstrated in the ligated ileal loop of rabbit only after administration of 5-10 fold concentrated culture filtrate and the second fraction.

Animals↗
PubMed1976

Influence of early weaning on the activity of several enzymes in the liver of rat.

In normally weaned rats the activity of two enzymes in rat liver, i.e. ATP citrate lyase and malic enzyme, gradually increases between the end of the third and the beginning of the fourth postnatal week. The activity of mitochondrial alpha-glycerophosphate oxidase remains unchanged during this period. Early weaning on the 18th postnatal day causes a rapid increase in activity of these enzymes. The impulse for this increase is very probably the change from high fat milk diet to high carbohydrate standard laboratory diet, the decrease of blood lipids, the activation of thyroid gland and changes of sensitivity of hepatic cells towards thyroid hormones. These results showed that early weaning modifies to the known picture of physiological weaning to a great extent.

ATP Citrate (pro-S)-Lyase↗
PubMed1976

Blood lipids during normal and early weaning in rats.

In young rats reared with their mothers, a gradual increase of serum cholesterol, triglycerides, phospholipids and total lipids was found between the 7th and the 18th to 22nd postnatal day. Then the concentrations of lipids gradually decrease. Early weaning at the 18th postnatal day causes a precocious decrease of the concentration of all studied lipids in blood so that their values on days 22 and 26 are significantly lower than in animals weaned on the 30th postnatal day. The body weight of early weaned rats decreases only slightly and returns to normal by the 30th day. The changes in serum lipids after early weaning are caused by differences in the amount of cholesterol and other lipids in breast milk, in comparison with those in the standard laboratory diet. Perhaps they may participate in disturbing the homeostatic equilibrium of cholesterol in early weaned rats.

Age Factors↗