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M Thibon

Publications and source records attributed to M Thibon.

At least 19 recordsLinked to original sources
PubMed1991

K-tuple frequency in the human genome and polymerase chain reaction.

The frequency occurrences of K-tuple (overlapping sequences of defined length, K) were computed from the known human genome sequences. The significance of these frequencies for the whole human genome was tested by polymerase chain reaction (PCR). A computer programs based on these results was written to choose primers to amplify DNA target sequences, either of human genes or of human infectious agents. The software also gave nested primer sequences which were used to synthesize non radioactive probes by PCR. We applied these two methods, primer selection and non radioactive probes, to easily and quickly set up very efficient PCR sets to work in the human genome context.

Algorithms↗
PubMed1988

Clinical presentation of louse-borne relapsing fever among Ethiopian refugees in northern Somalia.

Louse-borne relapsing fever (LBRF) is still endemic among Ethiopian populations. In order to assess the clinical presentation of LBRF in an Ethiopian refugee camp in northern Somalia, a referral system was organized for all pyrexias of unknown origin. Among the 134 patients referred, 37 showed Borrelia in fresh and stained blood smears. Common clinical features were: high fever (above 39 degrees C in 73% of the cases), headache and general body pain (88%), liver tenderness (62%), petechia (54%), nausea and vomiting (46%), chills and rigors (30%) and epistaxis (11%). Jaundice was absent. No fatalities were observed. The clinical picture was less severe than in previous studies on LBRF. This difference might be due to the fact that the present study was community-based as opposed to the previous studies which were hospital-based.

Adolescent↗
PubMed1984

Lung alterations in guinea-pigs infected with influenza virus.

Guinea-pigs were infected intranasally with influenza A Hong Kong 68 (H3N2) virus. Infective particles were re-isolated from lung homogenates up to 3 days after inoculation and indicated local replication. The subsequent lung inflammatory stages were studied by light microscopy, scanning and transmission electron microscopy (TEM). Lung alterations appeared after 24 h and intensified up to 7 days after virus inoculation, progressively decreasing until 3 weeks thereafter. The damage was reversible and complete restoration of structure was obtained within 5 weeks. The lesions commenced with the infiltration of bronchiolar and alveolar walls by polymorphonuclear cells, histiocytes and macrophages. A purulent exudate was seen to occupy the bronchiolar lumen. Cilia disappeared from tracheal and bronchiolar epithelia. Tracheal epithelium desquamated in some animals. TEM examination showed deterioration in type I pneumocytes, an increase in type II pneumocytes and concomitant damage to alveolar capillaries. Alveolar oedema and fibrinous deposits were seen. The pleura presented slight modifications. These results show that infection of guinea-pigs with influenza virus is a useful model for the study of lung pathology associated with a non-lethal respiratory viral infection.

Animals↗
PubMed1983

Auto-antibody dependent activation of the autologous classical complement pathway by guinea-pig red cells treated with influenza virus or neuraminidase: in vitro and in vivo study.

Guinea-pig erythrocytes that had been exposed to influenza A virus or Vibrio cholerae neuraminidase activated the classical complement pathway in autologous serum. Because all viral particles were eluted from the treated cells, activation was not dependent on anti-viral antibodies or on the particles themselves. After a threshold of 45-55% desialation, had been reached, the relative capacity of treated cells to activate complement increased very rapidly with desialation. Desialation unmasked sites on which natural auto-antibodies of the IgM class were fixed. Antibody fixation on the membrane led to C3b deposition on the cell membrane and activation of the classical complement sequence then cell lysis. The relevance of in vitro lysis of desialated cells to in vivo clearance of these cells is not certain because C4-deficient guinea-pigs were able to eliminate desialated cells from the blood stream as efficiently as did normal guinea-pigs. Nevertheless, membrane desialation occurring during myxovirus infection could lead to autoimmunity and tissue changes, as well as to recovery by eliminating virus-modified cells.

Animals↗
PubMed1982

Guinea pig erythrocytes, after their contact with influenza virus, acquire the ability to activate the human alternative complement pathway through virus-induced desialation of the cells.

Guinea pig erythrocytes that had been exposed to influenza A virus activated the alternative complement pathway in whole human serum in the absence of natural antibodies. Because all virus particles were eluted from the treated cells, activation was not dependent on antiviral antibodies or on virus particles themselves. The relative capacity of treated erythrocytes to activate the alternative pathway was dependent on the amount of virus to which the cells had been exposed and was directly related to the amount of sialic acid removed from the erythrocyte membrane during incubation with either whole virus particles or purified viral sialidase. C3b bound to cells that had been treated with virus, and P-stabilized amplification convertase sites P,C3b,Bb formed on these cells, exhibited increased resistance to the action of the regulatory proteins beta-1H and C3b Ina compared with C3b and P,C3b,Bb on untreated, nonactivating cells. The acquired resistance of the cell-bound, P-stabilized amplification convertase to decay-dissociation by beta-1H was directly related to the activating capacity of the treated cells in whole serum (r = 0.95) and to the amount of sialic acid removed from the cells by the virus (r = 0.98). Desialation represents a specific alteration of the cell surface by which a nonimmune host, through activation of the alternative pathway, may deposit C3b on a target cell that had been exposed to influenza virus and may lyse virus virus-modified cells during orthomyxovirus infections.

Animals↗
PubMedDate not supplied

Antibody response to anti-A/New Jersey/76 vaccines.

Experimental inactivated influenza vaccines prepared with strain X 53, derived from A/New Jersey/76 virus were injected to several groups of subjects. Different compositions of vaccine were used and the subjects were selected from different age groups. Antibody responses were measured 15 days after vaccination; it was then possible to evaluate the conversion rates, the percentages of subjects showing a protective level of antibodies and the average level of antibodies. The results show that a very small dose of antigen, probably acting as a booster, gives very good results in the older age group. On the other hand, young adults (below 23) react to a much lower degree to the vaccine. The results are discussed in relation to the age distribution of preexisting antibodies in the experimental groups and in the general population in France.

Adult↗
PubMedDate not supplied

Effects of vaccination on an influenza epidemic in a geriatric hospital.

During winter 75/76 (from February 1 to March 31) we got the opportunity to follow the incidence of an influenza epidemic that occurred in the geriatric hospital of Ivry. Its population was, on the average, 83 years old. 958 persons were involved in this study: 523 out of them had been vaccinated with Pasteur bivalent Mutagrip A + B vaccine. The epidemic had a double origin: it was due to a virus A/Victoria and to a virus B/Hong Kong. A significant difference was noted between the vaccinated group and the nonvaccinated one. Serological (CF and HI) and virological investigations (virus isolation) were performed on 110 subjects. The clinical course followed by the disease was mild for the vaccinated and severe for the nonvaccinated. Mortality rate was 0.19% in the former against 3.90% in the latter. It has been thus possible to observe an "immunological fence" since it appears that when 79% of a given unit has been vaccinated, influenza incidence has been as much as three times reduced.

Aged↗