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Biomedical subjects

B Ivanoff

Publications and source records attributed to B Ivanoff.

89 records · Page 5Linked to original sources
PubMed1977

[Evolution of mouse intestinal and blood immunoglobulins after oral route vaccination].

The authors have studied the mice immunoglobulins level after vaccination by oral route with a killed-pathogenic strain of Salmonella typhimurium and an avirulent mutant of the same bacteria. The obtained results show an increase of the intestinal IgA and IgG1 levels and a slighter one of sera IgG between the 10 th and 30 th day following immunization. No correlation was observed concerning the IgM, IgG and IgA levels and the mice protection against a challenge of pathogenic bacteria.

Administration, Oral↗
PubMed1976

Compared efficiency of a killed vaccine of Salmonella typhimurium, a live vaccine and an antigenic fraction in oral immunization of mice.

In an attempt to determine the best method of immunizing mice by oral route against Salmonella typhimurium, the animals were vaccinated by means of a killed-pathogenic strain, an avirulent mutant of the same bacteria, and a protective antigen removed from the supernatant culture of this mutant. After changing doses of vaccines and the interval between vaccination and challenge, the results obtained show the superiority of the live vaccine and protective antigen with regard to the killed one. Under our experimental conditions enteral vaccination appears to be more effective than the parenteral one.

Administration, Oral↗
PubMedDate not supplied

Antibiotic susceptibility in relation to serogroup and auxotype of Neisseria gonorrhoeae isolates from Gabon.

We tested 75 beta-lactamase-positive (penicillinase-producing Neisseria gonorrhoeae; PPNG) and 147 beta-lactamase negative (non-PPNG) strains of N. gonorrhoeae obtained during a two-year period in Franceville, a semirural community in southeastern Gabon, for susceptibility to antimicrobial agents, auxotype, and serotype. The most common auxotypes were the nonrequiring and proline-requiring strains. Of the non-PPNG strains tested, 37% belonged to serogroup WI, 48% to serogroup WII, and 15% could not be grouped with commercially available antisera. Except for four strains that belonged to serogroup WII, the PPNG strains were classified as serogroup WI or ungroupable. We determined the concentrations at which 90% of strains were inhibited (MIC90) for spectinomycin (32 mg/liter for both PPNG and non-PPNG), kanamycin (32 mg/liter for both PPNG and non-PPNG), tetracycline (2 mg/liter for non-PPNG, 1 mg/liter for PPNG), cefotaxime (0.03 mg/liter for non-PPNG, 0.008 mg/liter for PPNG), and penicillin (1 mg/liter for non-PPNG, greater than 32 mg/liter for PPNG). A MIC of greater than or equal to 2 mg of tetracycline/liter was noted for 17% of the strains. Strains belonging to serogroup WII were more resistant to tetracycline and cefotaxime than other strains. Proline-requiring strains were less susceptible to tetracycline, cefotaxime, and spectinomycin than the nonrequiring strains. The decreased sensitivity to penicillin (non-PPNG strains) and tetracycline was determined by proline-requiring strains belonging to serogroup WII.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Experimental cholera in monkeys].

The immune response to Vibrio cholerae was studied in baboons, rhesus monkeys and marmosets inoculated by the oral, intraintestinal or intravenous route with various strains of V. cholerae. Sera were collected from all animals on days 2, 6, 10, 17, 24, 32, 45 and 60 after infection. Serum protein, immunoglobulins (IgA, IgG, IgM), GOT, and alkaline phosphatases were determined. The results showed that baboons and rhesus monkeys were not susceptible to cholera infection under these experimental conditions. However, we were able to induce a lethal cholera infection in cotton-topped marmosets. In baboons and rhesus monkeys serum IgG levels decreased significantly following inoculation with V. cholerae; however, the ratio of GOT, alkaline phosphatase and antibodies against toxin were only slightly modified.

Alkaline Phosphatase↗
PubMedDate not supplied

[Three successive cases of salmonella meningitis in Gabon].

In a two months period Salmonella ajiobo and S. typhimurium (twice) were isolated from cloudy cerebrospinal fluids (CSF) of children less than one year old. No other cases of Salmonella meningitis occurred in a 2 year survey of meningitis in Franceville, a semi-rural community in southeastern Gabon. One case was fatal and the case with S. ajiobo needed a prolonged course since the CSF was not sterilized even after 6 days of therapy.

Female↗
PubMedDate not supplied

[Acute gastroenteritis and breast feeding in Gabon. Preliminary results].

76 diarrheic infants (from 15 days to 2 years) had a stool examination for rotavirus (ELISA method) and a stool culture and were classified according to breast feeding or not. This study was performed in a semi-urban region (Haut-Ogooué, Gabon). The preliminary results suggest a protection by breast feeding against rotavirus and enteropathogenic bacteria, rapid elimination of diarrheic agents may be facilitated by human milk.

Acute Disease↗
PubMedDate not supplied

Secondary immune response to oral and nasal rough mutant strains of Salmonella typhimurium.

The variations in anti-Salmonella typhimurium antibody levels was measured in BALB/c mice which had been orally and nasally vaccinated with S. typhimurium live mutants of different lipopolysaccharide lengths. Together with the demonstration of immunological memory, the intensity of the secondary response was correlated with the length of the polysaccharide chain at intestinal and serum levels. Nasally administered antigen seemed to be at least as immunogenic as when orally administered.

Administration, Intranasal↗
PubMedDate not supplied

[Serological survey for arbovirus antibodies in the human and simian populations of the South-East of Gabon (author's transl)].

A serological survey for arbovirus antibodies was carried out in human and simian populations of the South-East of Gabon. 197 human sera (adults), 34 simian sera (collected in the monkey colony of the Centre International de Recherches Médicales de Franceville) and 28 paired sera of mothers and their new-borns (samples collected from the umbilical cord) were tested using haemagglutination inhibition (HI) for all sera and complement fixation test (CF) for some of them. In the human population, 88% showed antibodies against yellow-fever virus as a consequence of vaccination, 20% against Chikungunya virus and 58% against Orungo virus. The high antibody titers for Chikungunya virus detected by HI test with CF antibodies proved a recent activity of this virus. The serological survey of simian population confirms the activity of Chikungunya virus in this area and demonstrates the circulation of one or more Flaviviruses, especially Zika virus. Transmission of maternal antibodies was established for the following arboviruses: Chikungunya, yellow-fever, Uganda S., Zika and Orungo.

Adult↗
PubMedDate not supplied

Protective immunity and the cell-mediated immune response in mice following oral administration of an avirulent strain of Salmonella typhimurium.

Oral vaccination with Salmonella typhi-murium M 206 has been shown to confer highly significant protection on BALB/c and low-responder (LR) Biozzi mice a 30 days, but no protection was observed in high-responder (HR) Biozzi mice. None of the three strains showed any evidence of significant protection 10 days after primary vaccination. A correlation was noted between the degree of protection and the results of tests measuring cell-mediated immunity, both in vitro (MIF test), and in vivo (colloidal carbon clearance). Phagocytosis was significantly more active in vaccinated mice, both at days 10 and 30, except in HR mice. MIF production was only found at day 10 in HR mice, and was present at day 30 in both HR and LR mice. Our results emphasize the importance of the role of macrophage phagocytosis in the protection of mice against Salmonella infections.

Administration, Oral↗
PubMedDate not supplied

[Experimental infection by "Salmonella typhi-murium": protective role of homologous ribosomal extracts in calves (author's transl)].

Eleven calves, 6 months old, vaccinated or not, have been infected experimentally with 10(7) Salmonella typhi-murium, administered by oral route. The control calves had a serious illness, characterized by a severe diarrhoea, hepatic and renal symptoms and a heavy infestation of the main organs. The other five calves, which were orally and subcutaneously vaccinated with ribosomal extracts of S. typhi-murium and S. dublin showed only a moderate alteration of their health while biochemical disorders at the level of liver and kidneys disappeared. However, salmonella were found in mesenteric lymph nodes, but in much lower amounts than in controls.

Animals↗
PubMedDate not supplied

[An ELISA study of the intestinal and serum anti-LPS antibody response in BALB/c mice fed with various mutants of "Salmonella typhi-murium" (author's transl)].

The specific anti-LPS serum antibody response in BALB/c mice, before and after an oral booster with different non-pathogenic strains of Salmonella typhi-murium, was measured by an ELISA technique. Serum response to LPS was found to depend on the length of the LPS polysaccharide moiety in "rough" mutants. The M206 "smooth" mutant induced a less marked anti-LPS response. The immunogenicity of the polysaccharidic "core" appears to be modified by the O antigen. The specific antibody response in the gut only becomes marked following after booster of Ra, Rc and M206 mutants.

Animals↗