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Biomedical subjects

A S BENENSON

Publications and source records attributed to A S BENENSON.

At least 19 recordsLinked to original sources
PubMed1964

SEROLOGICAL RESPONSES OF MAN TO TYPHOID VACCINES.

Study of the serological responses in man to typhoid vaccines tested in several WHO-sponsored controlled field trials in British Guiana, Poland and Yugoslavia has not indicated any correlation between the level of Vi and O antibodies elicited and the effectiveness of the vaccines. Instead, the more effective vaccines have elicited significantly greater H-antibody responses; but a variety of factors suggests that it may in fact not be the antibody that confers immunity to the disease. The phagocytic test does not appear promising as a technique for determining the effectiveness of a typhoid vaccine, but passive protection of the chick-embryo may warrant further investigation.

Antibodies↗
PubMed1964

RAPID IDENTIFICATION OF VIBRIO CHOLERAE BY DARKFIELD MICROSCOPY.

This article describes a rapid, simple and reproducible method for detecting Vibrio cholerae in diarrhoeal patients. The method involves darkfield examination of a liquid stool specimen or a rectal swab immersed in broth and immobilization of V. cholerae by the addition of specific vibrio antisera. The authors state that in 80% of cases a definitive diagnosis is available within five minutes. There is no need for elaborate equipment or long training of technicians and the method is easily performed by one person in the field.

Bacteriological Techniques↗
PubMed1963

BACTERIAL VACCINE IN MULTIDOSE TABLET FORM FOR PARENTERAL USE.

Dried typhoid vaccines were prepared by freeze-drying of heat-inactivated phenolized-cell suspensions and by an acetone-killed and dried technique. Portions of the dried powder obtained by each method were compressed into tablets. Tests with the products showed that drying and making of tablets did not affect the ability of the vaccines to protect mice or elicit antibodies in rabbits.

Acetone↗
PubMed1961

Studies on infection and immunity in experimental typhoid fever. III. Effect of prophylactic immunization.

A study was made of the efficacy of various antityphoid immunizing agents in immunizing chimpanzees against typhoid fever produced by feeding viable S. typhosa. It was found that both acetone-killed and heat-killed, phenol-preserved typhoid vaccines were effective in protecting against infection induced with either homologous or heterologous strains of typhoid bacilli. Purified O antigen induced no discernible protection, but some immunity was afforded by the administration of purified Vi antigen.

Animals↗
PubMed1960

Studies on infection and immunity in experimental typhoid fever. I. Typhoid fever in chimpanzees orally infected with Salmonella typhosa.

A disease resembling human typhoid fever has been induced by feeding live cultures of Salmonella typhosa to young chimpanzees, thus confirming the classical reports of Grünbaum and of Metchnikoff and Besredka. Detailed clinical observations, results of stool and blood cultures, and serological studies have confirmed the impression that the disease produced in chimpanzees closely resembles the mild form of human typhoid fever frequently seen in childhood. Gross and histologic examination of intestines, mesenteric lymph nodes, liver, spleen, and other organs of orally infected chimpanzees has demonstrated that the pathological findings are essentially indistinguishable from those seen in mild typhoid fever in man. The clinical spectrum of disease seen in chimpanzees ranged from moderately severe illness, through transitory illness, to afebrile infection with or without bacteriemia (but invariably with an antibody response), occasionally leading to the development of persisting biliary infection and the carrier state. Thus the range of illness observed in chimpanzees resembled that seen in man, except that the severe and complicated forms of typhoid fever were not observed in the chimpanzee. A reason for this difference is proposed and discussed. In contrast to the limitations imposed upon the interpretation of human epidemiologic observations, it has been possible to demonstrate in the chimpanzee that clinical variation in disease pattern from animal to animal may occur despite the administration of the same dose of the same bacterial strain simultaneously to an entire group of animals under study; in other words, variation in clinical pattern is dependent on inherent, non-specific host factors as well as on dose, strain or preceding state of immunity. Variation in dose and in challenge strain of S. typhosa employed also appeared to have an effect upon the likelihood of producing febrile as against afebrile infection in chimpanzees. The dose required to produce clinical disease, even with the more virulent strain, was excessively large compared to what is believed to be the dose required to produce illness in man; the limitations of this assumption, and suggested explanations for the findings, are discussed. The production of the spectrum of typhoid fever in the chimpanzee has made possible the study of basic problems in this disease which are not amenable to definitive study through the use of prevailing laboratory techniques.

Animals↗
PubMed1959

Laboratory tests of typhoid vaccines used in a controlled field study.

In 1954-55, a controlled field trial of two types of typhoid vaccine-alcoholized ("vaccine A") and phenolized ("vaccine F")-prepared in Yugoslavia was carried out in the town and district of Osijek. In an attempt to correlate the protection conferred on man by these vaccines with their potency in laboratory animals, arrangements were made for laboratory tests to be performed jointly by the Central Institute of Hygiene, Zagreb, Yugoslavia; the Lister Institute of Preventive Medicine, Elstree, Herts, England; and the Walter Reed Army Institute of Research (WRAIR), Washington, D.C., USA. In this paper, the results of the WRAIR tests are presented.The potency relationship between vaccine A and vaccine F was found to vary with the type of test performed. According to active-immunization tests in mice, using either mucin or saline challenge, vaccine A was more potent than vaccine F, as it proved also in the passive immunization of mice with saline challenge and in Vi-antibody production in rabbits. As judged by the results of the passive immunization of mice with mucin challenge and of O-antibody production in rabbits, there was, however, no clear-cut difference in potency between the two vaccines. And, as indicated by H-antibody production in rabbits, vaccine F was clearly superior to vaccine A. Since vaccine F was also the more effective in man, the last-mentioned findings are of considerable interest, suggesting that the H antigen may be more, and the Vi antigen less, important in protecting man against typhoid fever than is currently considered to be the case.

Animals↗