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M Sitbon

Publications and source records attributed to M Sitbon.

51 records · Page 3Linked to original sources
PubMed1985

Human-enteric-coronaviruslike particles (CVLP) with different epidemiological characteristics.

One hundred fifty-six diarrheic and 115 control stools collected throughout a year from nonhospitalized children were examined by electron microscopy in Haut-Ogooué, Gabon; 65.2% of the controls and 38.5% of the diarrheics were found to contain coronavirus particles (CVLP). In both diarrheic and control groups the CVLP prevalences showed a seasonal variation whereas significant variation of prevalence with age was observed only in the controls. Thus, the CVLP in controls were significantly more abundant in children over 2 years old (76% vs 48%, P less than .01) and more frequently observed during the months of rainy seasons (75% vs 54%, P less than .02). On the other hand, the higher prevalence of CVLP in diarrheics over 2 years old was not significant (48% vs 36%, P = .20), whereas a significantly lower prevalence of CVLP during the months of rainy seasons was observed in this group (27% vs 50%, P less than .01). Studies of the climatological factors in this equatorial climate showed a parallel cyclical variation of parameters representing rainfall, temperature, as well as relative humidity. We were not able to distinguish which of these factors was influencing more directly the prevalence of CVLP.

Age Factors↗
PubMed1985

Rotavirus prevalence and relationships with climatological factors in Gabon, Africa.

A one-year study of rotavirus prevalence was carried out using electron microscopy in Gabon, equatorial Africa. One hundred fifty-six nonhospitalized diarrheic children up to 10 years of age and 115 age-matched controls were investigated together with diarrheic adults and children over 10 years of age. Rotaviruses were observed only in diarrheic children under 10 years of age (10.2%). Rotaviruses were more prevalent in the dry-season months (19.2% versus 1.3%, P less than .001). Rotaviruses were the most commonly found among all the viral, bacterial, and parasitic agents we detected, with the exception of the coronaviruslike particles, which are the subject of another paper [Sitbon, 1985].

Adolescent↗
PubMed1985

Use of a focal immunofluorescence assay on live cells for quantitation of retroviruses: distinction of host range classes in virus mixtures and biological cloning of dual-tropic murine leukemia viruses.

A rapid and sensitive focal immunofluorescence assay (FIA) using monoclonal antibodies or heterologous antisera was employed for detection and biological cloning of viruses capable of inducing viral antigens on cell surfaces. The FIA was performed directly on a variety of live cells in tissue culture dishes and was used successfully with C-type murine leukemia viruses (MuLV) of different tropism including ecotropic, xenotropic, amphotropic, and dual-tropic recombinant mink cell focus-inducing (MCF) viruses. With the FIA, we were able to titrate and distinguish ecotropic Friend-MuLV and Friend-MCF viruses present in mixtures. Dual-tropic MCF viruses could be specifically detected directly in mouse cells by using MCF-specific monoclonal antibodies. These antibodies replaced the requirement for production of typical MCF cytopathic effect in mink cells for MCF virus detection, and also allowed efficient titration in mouse cells of MCF virions pseudotyped with ecotropic envelope proteins. Furthermore, by picking foci of fluorescent cells and using their cell-free viral progeny, MCF viruses were cloned from complex pseudotypic mixtures. This allowed the cloning of viruses present at low frequency in heterogeneous mixtures obtained from leukemic tissues.

Animals↗
PubMed1985

[Etiology of acute infantile gastroenteritis in Gabon].

Rotaviruses are the main etiology of acute diarrhoeas in gabonese children (11 to 30% according to age). Salmonellae (11.4%), Shigellae (7.1%) and E. histolytica (7.1%), isolated or associated with enterobacteria, E. coli (3%), Giardia and Strongyloides stercoralis (1.4%), Yersinia enterocolitica (1%) and Balantidium coli (0.5%) were also found, without cholera.

Adolescent↗
PubMed1983

Anti-influenza human T killer cells present an intertypic activity anti-A and -B type viruses in a secondary reaction in vitro.

In man influenza viruses induce a cytolytic T lymphocyte (CTL) activity directed against autologous or HLA-A or -B compatible target cells infected with the immunizing virus. While only type specific CTL are characterized in man, we report here experiments showing intertypic activities of human CTL from donors vaccinated with both A and B type influenza viruses. Their peripheral blood leucocytes (PBL) restimulated in vitro with live influenza virus of one type gave rise to both anti-A and -B activities, when non-infected or Sendaï infected target cells were not lysed. These intertypic activities were restricted by HLA-A or -B antigens and were inhibited by OKT3 antibody. When u.v.-inactivated viruses were used as restimulating antigen, no intertypic CTL were obtained. The results of competition experiments with cold targets show that no common antigens were recognized by anti-A and anti-B CTL. Moreover the restricting HLA-A or -B molecules seen in association with A or B types viruses appeared different in the same experiment, confirming that different antigens were probably involved for the agents of A and B subgroups. This influenza specific intertypic activity was therefore probably due to an intertypic stimulation of type specific CTL activities, possibly arising at the level of T helper cells.

Antigens, Viral↗
PubMed1980

[Presence of enteric viruses in non-diarrheic canine stools].

Rota-, corona- and parvovirus particles have been visualized by direct electron microscopy in canine stools collected at random in Paris streets. A possible involvement of these viruses in gastroenteric diseases is discussed in the light of these findings.

Animals↗
PubMed1980

Electron microscopy detection and characterization of viral particles in dog stools.

A number of apparently normal dog stool samples, randomly collected on the sidewalks of Paris were examined by Electron Microscopy. The study revealed the presence of viral particles in 27 cases. Morphological criteria lead to the characterization of rotavirus in 2 specimen, coronavirus in 7 and parvovirus in 5. Rotavirus particles appeared always alone while coronavirus and parvovirus particles were present together in 5 cases. Similar particles have been implicated in animal and human gastroenteritis. The importance of their presence in canine dejections is discussed in view of pollution by dog stools of urban and suburban areas.

Animals↗
PubMedDate not supplied

[Calcium channel modulators as antidotes in fatal imipramine poisoning].

Calcium entry modulators were tested as antidotes to imipramine lethal toxicity. 42 rats were administered intraperitoneally 85 mg/kg of imipramine. In 6 control rats, hypotension and bradycardia were observed. Survival time was 15' +/- 5'. Survival time of rats treated with intraarterial nitrendipine was 21' +/- 11'. Survival time of 5 out of 6 rats treated by intraarterial verapamil or diltiazem was respectively 19'00" +/- 14'30" and 40'30" +/- 32'00". 5 out of 6 rats treated by intraarterial nimodipine, as well as all of the rats treated by flunarizine or nicardipine survived and were alive and active 48 hours later. Intoxication with imipramine may induce life threatening complications for which there are no specific medication. Nicardipine might be considered in the treatment of acute poisoning by imipramine and related tricyclic compounds.

Animals↗