Biomedical subjects
Publications and source records attributed to G Tixier.
Since 1754 in Vichy the poor have been admitted in a new hospital with 70 beds. In 1759 Doctor Inspector of thermal waters, Emmanuel Tardy, wants for sick people new purgative medications. Ten preparation, and the lenitive, are made for the children, the pregnant women, and the men as in the famous Manuel des Dames de Charite.
The evaluation of the ELISA technique has been studied in the special case of its application to the serological diagnosis of chlamydiosis in goats. The results showed that this technique is reliable (accurate and reproducible) and efficient. Sera from 96 goats were studied with the ELISA technique, indirect immunofluorescence (IIF) and complement fixation (CF), the latter being the standard method in France. A comparison of the results revealed a similarity of findings with ELISA and indirect immunofluorescence and the greater sensitivity of the ELISA technique relative to that of complement fixation.
The serological responses following a primary vaccination carried out one year before in two groups of dogs which received an inactivated cell culture vaccine containing or not an adjuvant (alumine-hydroxide) are compared. Neutralizing antibody titers assayed in mice, obtained with only one injection of the adjuvanted vaccine are at the same or a greater level than those induced by two injections of the non-adjuvanted vaccine administered two to four weeks apart (statutory schedule of rabies primary vaccination applied in France).
The challenge we carried out, which regularly brought about the death of the control animals, led us to study the different factors influencing the pathogenicity of the rabies virus. So, the method of preparation is important. The strain NYC, prepared from the salivary glands is extremely pathogenic for dogs; however, when it is prepared from mouse brains after nine passages have been made, it proves to be already partially modified. One then notices a death-rate which is less severe, even when larger quantities of virus are employed, and also the presence of some aberrant phenomena. (The survival of some of the infected animals and the nature of their inapparent forms of infection were confirmed by serology.) The significance of the route of inoculation in the different species of animals was studied. The injection in the crotaphytes was reserved for dogs, the cervical muscles for cats and the masseters for sheep. Paradoxically, cats prove to be most resistant to the challenge under our conditions. Finally the numerical data, allowing us to compare the different strains, modified, fixed or wild, was established. The data was based on the incubation period and on the differences between the titres obtained via intramuscular routes and intracerebral routes in the mice.
This work reports on two distinct studies on the analysis of correlation of results of potency tests of rabies vaccine intended for dogs. In a first study, the analysis compares the results of the conventional NIH test in mice with seroneutralizing antibodies obtained after 21 days of vaccination in dogs. Arithmetical analysis (109 NIH results, 466 antibody titres) did not reveal significant linear correlation between the results. In a second study, the analysis compares the results of the conventional NIH test and of the NIH test without booster in mice with seroneutralizing antibodies obtained after 21 days of vaccination in dogs. Arithmetical analysis (27 conventional NIH results (without booster), 118 antibody titres) did not reveal any significant linear correlation between the results.
In this study, we report some technical improvements which enable us to envisage wider use of the haemagglutination test and haemagglutination inhibition of the rabies virus. Moderated trypsination of sensitive red blood cells and their counting are important parameters. An interesting application of the test was the haemagglutination competition enabling the amount of soluble glycoprotein (obtained during the fractionating of the virus components) to be evaluated. From antibody kinetics of vaccinated dogs, a study of the correlation which exists between the IHA titres, SN mice titres and SN-RFFIT titres was carried out. Satisfactory correlation was obtained between these three techniques.
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The authors present a disposable device which may be used for skin tests studying delayed cellular hypersensitivity with 7 antigens and a glycerin control. With the aim of more objective evaluation of the results, they suggest the establishment of a score taking into account the number of positive reactions and the degree of the reactions. Finally, they describe the results of a large multicentre study involving 830 subjects considered to be healthy and divided into 4 groups according to the response to the tests.
The microculture plaque titration of virus shows an important disadvantage : the reduction of the areas observation brings out plaque convergence and prevents from their exact enumeration. Nevertheless, a method, proposed by Moore, enables the estimation of virus title. The influence of the dilution and repetition factors on the title precision has been investigated. Two examples are treated.
We show that in enterotoxic or not enterotoxic E. coli strains from various origins, enterotoxic strains of E. coli from calves only agglutin horse red cells in presence of mannose. The haemagglutinins structure, not visible with electron microscope is compatible with presence of fimbriae. It would be K 99 antigen, specific adhesiveness structure for strains from calves.
Delta toxin, a hemolytic exocellular protein excreted by C. perfringens type C has been purified to homogeneity, assessed by polyacrylamide disc gel electrophoresis. Purification steps involved successively calcium phosphate gel formation in culture supernatant fluid, salting-out of unadsorbed material by ammonium sulfate to 50 % saturation, isoelectric focusing and gel filtration on Sephadex G75. Purified toxin appears as a basic protein occuring in two forms with isoelectric points of 8.8 and 9.4 as disclosed by isoelectric focusing. Molecular weight estimated by SDS-polyacrylamide disc gel electrophoresis was found to be close to 42,000 for the two forms. The lytic activity of delta toxin is inhibited by Ca++ and EDTA. The toxin is activated by short-term treatment with low concentration of trypsin.