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Biomedical subjects

O FELSENFELD

Publications and source records attributed to O FELSENFELD.

At least 19 recordsLinked to original sources
PubMed1964

[CHOLERA 1964].

Explore the source record for details and available documents.

Anti-Bacterial Agents↗
PubMed1964

AGGLUTINATING, LETHAL TOXIN AND E1 TOR HAEMOLYSIN NEUTRALIZING POTENCY OF SERA IN CHOLERA.

There is a lack of agreement as to the significance of agglutination test results in cholera, and recent epidemics of "classic" Vibrio comma and El Tor infections have provided an opportunity to compare this test with two other serological procedures recently introduced in cholera work. These are determination of the circulating antitoxin expressed as the lethal toxin neutralizing power of a serum, and determination of the haemolysin neutralizing power through serial test-tube dilutions.Applying these tests to sera from cholera patients, convalescents, carriers and contacts and from immunized persons either exposed or not exposed to cholera, the authors found the agglutination test to be a less sensitive indicator of the immunological status than the other two procedures. They therefore recommend antitoxin and antihaemolysin titration for the study of cholera patients, convalescents and carriers. In the conditions of the experiments described, the results with exposed and non-exposed vaccinated individuals were less conclusive, but nevertheless suggest that antitoxin and antihaemolysin tests may be helpful in the follow-up of vaccination experiments.

Agglutination Tests↗
PubMed1963

Serological analysis of supernatant liquids of cultures of El Tor vibrios.

Watanabe, Y. (406th Medical General Laboratory, U.S. Army Medical Center, Japan) and O. Felsenfeld. Serological analysis of supernatant liquids of cultures of El Tor vibrios. J. Bacteriol. 85:31-36. 1963.-Supernatant liquids of cultures of El Tor vibrios were analyzed serologically by applying the Ouchterlony agar diffusion technique. There are at least three different water-soluble antigenic components: thermolabile and exotoxin-like, thermolabile-bacterial, and thermostable-bacterial. All rabbit sera containing antibody(s) against the thermolabile exotoxin-like antigen(s) neutralized the lethal and hemolytic activities of the supernatant liquids of the cultures. These antibodies behave differently when absorbed with bacterial cells. The antihemolytic activity was not absorbed, whereas the antilethal was partially absorbed. The possibility of the existence of a nonactive toxin(s), which can stimulate production of antibodies against the lethal and hemolytic principles in the rabbit, was indicated.

Animals↗
PubMed1963

Some observations on the cholera (E1 Tor) epidemic in 1961-62.

The author discusses some of the features of the cholera epidemic caused by El Tor vibrios in 1961-62 in the Western Pacific. The disease originated in the Celebes and spread from there to other parts of Indonesia, to Sarawak and, possibly, to Kwangtung. Hong Kong and Macau were most probably infected from Kwangtung. Subsequently the disease reached the Philippines, progressing from Manila southwards to the other islands, whence it invaded British Borneo. The El Tor epidemic did not differ clinically or epidemiologically from other cholera outbreaks observed during the past decade. The disease attacked poor, under-nourished people living under insanitary conditions. It spread along the coastline and, to a limited extent, along inland waterways. The authorities in the affected territories recommended that the quarantine regulations, sanitary measures and treatment methods used against cholera caused by the so-called "true" cholera vibrios be applied also to cholera caused by El Tor vibrios.

Cholera↗
PubMed1961

Production of vibrio El Tor toxin in a liquid medium.

Watanabe, Yoshikazu (U. S. Army Medical Center, Japan), and Oscar Felsenfeld. Production of vibrio El Tor toxin in a liquid medium. J. Bacteriol. 82:43-47. 1961.-High toxin titers (as measured by mouth lethality and hemolytic activity) were obtained from culture supernatants of strains of El Tor vibrio isolated from patients in Indonesia. Cultivation of the organism in vitro revealed that the concentration of ferrous ion in the medium was critical for the production of maximal yields of toxin. Toxins produced under appropriate conditions were antigenic in rabbits and produced antibodies capable of neutralizing both the hemolytic and lethal actions in multiple proportion. Suggestive evidence has been obtained that the hemolytic and lethal toxins may be separate molecules.

Animals↗