PubMed Health⌕ Search

Biomedical subjects

A Vertényi

Publications and source records attributed to A Vertényi.

At least 19 recordsLinked to original sources
PubMed1979

Shigella dysenteriae 1-like cytotoxic enterotoxins produced by Salmonella strains.

A Salmonella enteritidis strain produced a cytotoxin in addition to heat-labile (LT) and heat-stable (ST) enterotoxins. Two strains of serotypes Salmonella kapemba and Salmonella thompson were LT and ST negative, but exhibited a cytotoxic effect. After Sephadex G-100 fractionation of the crude S. enteritidis material, some high and low molecular fractions had both cytotonic and cytotoxic activities. Of the two other salmonellae, only some high molecular fractions contained the cytotoxic substance. Neutralization experiments revealed an antigenic relationship between the cytotoxins studied and Shigella dysenteriae 1 enterotoxin. On the basis of cross neutralization and other data, it seems that cytotoxic and LT-like characters are carried by the same molecule. In S. thompson and S. kapemba the LT fails to exert a biological effect, although it is antigenically related to the LT of Escherichia coli.

Animals↗
PubMed1979

An altered heart-labile enterotoxin (LT') produced by Escherichia coli serogroup O55 strain.

An Escherichia coli serogroup O55 strain produced heat-labile enterotoxin only, which exerted unusual effects on cell cultures; it caused elongation of CHO and HeLa cells but no changes in Y-1 cells. Injection of this substance, designated LT', into mouse foot pad and rabbit skin caused a well-expressed necrotic effect beside the LT-like activity. LT' showed no cytotoxic effect and failed to produce mouse lung oedema. The strain was not haemolytic. According to Sephadex G-100 fractionation, the LT' had a high molecular weight. The LT' and the necrotic activities could not be separated by fractionation. Neutralization experiments suggested an antigenic relationship between LT and LT'. The antigenic deficiency of LT' was closely related to the common antigenic component of LT and choleragen. The necrotic effect caused by crude LT' was neutralized only by the homologous serum.

Animals↗
PubMed1978

Heat-stable enterotoxin produced by Shigella flexneri.

Filtrates and ultrasonics extracts of Shigella flexneri showed rapid permeability factor (PF) test and proved positive in suckling mice and ligated rabbit loop tests within 4 hr. Delayed PF was not detected and the rabbit loop dilatation test read after 18 to 24 hr, the mouse pad oedema reaction, the test for elongation effect of CHO cells were also negative. In the delayed PF test a strong "blanching" effect was observed. A filtrate of an Ent-Escherichia coli strain was positive only in the rapid PF test, while filtrate and ultrasonic extract prepared from the Ent+ E. coli strain showed a positive reaction in all tests for enterotoxins (ST and LT) including the rapid PF test. Ultrasonic extracts of a S. flexneri and an Ent- E. coli strain concentrated by freeze-drying were fractionated on Sephadex G-100 column. S. flexneri fractions of 60--70ml were positive for rapid PF, dilation capacity in suckling mice, and the blanching effect in the delayed PF test. No positive reaction was found in the delayed PF test and in CHO cell culture. Similar fractions of Ent- E. Coli carried substances responsible for the rapid PF and the blanching effect, but without suckling mice positivity.

Bacterial Toxins↗
PubMed1978

Unique features of heat-stable enterotoxin of Shigella flexneri.

Sephadex G-100 fractions of ultrasonic lysate of Shigella felxneri were compared to the fractions of Escherichia coli lysates of Ent- , LT+ ST+, LT+ and ST+ strains. The range of molecular weight of S. flexneri ST fractions was the same as that of E. coli LT fractions. Rapid PF activity was associated with the ST peak in the case of S. flexneri, and followed the LT activity in the E. coli (LT+ ST+) fractions, and appeared in the same molecular weight range in the case of Ent- E. coli lysate. Cross neutralization could be demonstrated between S. flexneri ST and E. coli LT. Antigenic relationship between shigella ST and choleragen seemed to be less expressed and rather unilateral.

Animals↗
PubMed1978

Mouse lung oedema caused by a toxic substance of Escherichia coli strains.

Some Escherichia coli strains isolated from patients and instilled into the nostrils of mice cause a rapidly developing fatal, haemorrhagic lung oedema. Lung toxic strains were found in different serogroups, with the predominance of 04, 06, and 018. The toxic material seems to be bound to the cells; the toxin yield is poor by different methods of extraction. The toxic principle causes toxic, haemorrhagic oedema in mouse foot pad test and shows cytotoxicity for AV-3 cells. The "lung toxin" is heat labile and after Sephadex fractionation has a molecular weight of about 100 000 dalton. There is a possible identity with a toxic haemolysin.

Animals↗
PubMed1978

Enterotoxin production by Shigella flexneri type 2A, strain no. M42-43.

Enterotoxin produced by Shigella flexneri type 2a, strain M42-43, is similar to "Shig-like" cytotoxic enterotoxin and shares common features with that of other S. flexneri strains. On the basis of molecular filtration and neutralization experiments it is suggested that the same molecule carries these biological characters.

Animals↗
PubMed1978

Specificity of antipyrogenic immunity.

The specificity of antipyrogenic immunity as well as the structural differences of the Enterobacteria responsible for pyrogenicity have been studied. Strains S. minnesota Re 595 and S. typhimurium SL 1102 as well as glycolipids obtained from them, further E. coli 083 and E. coli F 576 as well as the LPS extracted from them were used in the experiments. In conformity with the results of chemical analysis it was found that the method reflected exactly the antigenicity of the receptors responsible for pyrogenicity. Alterations of the antipyrogenic immunity may indicate that the structure of the single endotoxins responsible for pyrogenicity are different in antigenicity.

Animals↗
PubMed1977

Oral immunization of monkeys with polyvalent dysentery vaccine.

Macaca mulatta monkeys were immunized orally with polyvalent Boivin extract of Shigella flexneri 2a, 3a, 4a, 4b, 6 and Shigella sonnei. The total immumizing dose for each component was equivalent to 1.2 X 10(12) cells. After challenge with 7.5 X 10(10) cells of a virulent S. flexneri 2a strain, out of 20 immunized animals 2 developed dysentery and 4 showed mild dyspepsia; all 6 control animals became ill with dysentery. Vaccination failed to influence the incidence, duration or the intermittent character of shigella excretion. Protective antibodies appeared in high titre in the serum of immunized animals.

Administration, Oral↗