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Biomedical subjects

L Monjour

Publications and source records attributed to L Monjour.

At least 73 records · Page 4Linked to original sources
PubMed1986

[Comparative study of research methods to assess water pollution of the fecal origin in the rural Sudan-Western Sahara environment].

In the assessment of the bacteriological quality of water from 1,500 drills World has not in Burkina-Faso, three methods have been analyzed comparatively. The first, relying upon bacterial production of H2S as indicator of faecal pollution and proposed by Indian workers, has been found unreliable for determining water potability. The second, based upon the nitrate content of water, is unable to reveal water contamination by human and animal excreta. The third method, employing a membrane filtration, is to be commended since it is well adapted to the Sahelian conditions. Simple, reliable, of low cost, this method is providing the quality assurance of water potability, a requirement which must accompany the drilling programs.

Animals↗
PubMed1985

[Measles vaccination in the Sudan-Sahel region of Africa. Absence of the immunodepressive effect of malaria].

A survey aiming at assessing the effectiveness of anti-measles vaccination was carried out in a rural Upper-Volta population. The haemagglutination inhibition technique was used for detection of anti-measles antibodies; a reciprocal antibody titer of 20 or more was considered as a positive one and the subject considered as immunized. In the age group of 1-3 years old studied here, malaria does not seem to be a factor that modulates the ability of vaccinated subjects of producing anti-measles antibodies. Thus the immunodepressive properties of the Plasmodium is not observed in this immunizing system which effectiveness has been further improved by the development of thermostable vaccines.

Burkina Faso↗
PubMed1985

[Monoclonal antibodies against defined Leishmania antigens protect mice against infection by different species of Leishmania].

Mice monoclonal antibodies (IgG) have been raised against Leishmania infantum promastigotes by fusing SP 2/0 myeloma cells and immunized mice splenic cells. The monoclonal antibodies have been detected by indirect immunofluorescence. In vivo tests showed that some of them could inhibit the life cycle of several Leishmania species from the Old and the New World. Studies of these protective monoclonals by the western blot technique showed the presence of three constant antigens (40 kD, 70 kD and 113 kD) amongst the Leishmania species studied.

Animals↗
PubMed1985

[Production of human monoclonal antibodies against various antigens of erythrocyte stages of Plasmodium falciparum].

Peripheral blood lymphocytes from 20 individuals living in a malaria endemic area (Burkina Faso) were transformed with Epstein-Barr virus. No antigen specific selection, nor stimulation of B-cells were performed prior to transformation. 20 cell lines were established, 14 secreted polyclonal antibodies directed against erythrocytic stages of Plasmodium falciparum. 4 lines were cloned and the supernatant analysed and characterised against Plasmodium falciparum antigens.

Animals↗
PubMed1985

[Efficacy of the vaccination of C57BL/6 mice against infection with different species of Leishmania].

Antigens were isolated from lysates of promastigotes of Leishmania infantum by electro-elution from polyacrylamide gels. Antigens with respective molecular weights for F2 = 94-67 kd; F5 = 30-20 kd and F6 below 20 kd, were injected intravenously in C 57 BL/6 mice. The immune sera were studied by indirect immunofluorescence; an in vivo test showed their inhibitory effect on the life cycle of several Leishmania species from the Old and the New world. Furthermore, mice immunized with F2, F5 or F6 were protected against an infection by Leishmania major. These results demonstrate that vaccination is efficient in mice differing genetically for either susceptibility (BALB/c) or partial resistance (C 57 BL/6) to Leishmania infections. Recently, we reported that a single monoclonal antibody raised against Leishmania infantum can prevent the development of Leishmania major and Leishmania mexicana amazonensis. Indeed, BALB/c mice injected subcutaneously with promastigotes pre-treated with this monoclonal antibody, did not present any cutaneous lesions over a period of 3 months. Using a mouse in vivo model--intraperitoneal injection of TG 180 mouse sarcoma cells along with monoclonal antibody pre-treated promastigotes--such an antibody-mediated inhibition was also observed against Old and New World Leishmania species. Protective monoclonal antibodies recognized by immunoblotting technique three antigenic fractions (40, 70 and 113 kd) common to several Leishmania species. Antigenic preparations from Leishmania infantum extracts were isolated by electro-elution from polyacrylamide gels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Abnormal anti-single stranded (ss) DNA activity in sera from Plasmodium falciparum infected individuals.

Sera from 32 subjects with Plasmodium falciparum parasitaemia were screened for the presence of antibodies to native-double stranded (ds) DNA and to heat-denaturated-single stranded (ss) DNA by a Farr DNA binding radioimmunoassay. In addition anti-dsDNA antibodies were also studied by indirect immunofluorescence using Crithidia luciliae and rat liver sections as substrates. Immunoglobulin (G, A, M) levels and plasmodial antibodies titres (PA) were concomitantly evaluated. The anti-ssDNA activity was higher in malarious individuals with high IgM levels than in normal or malarious individuals with normal IgM levels. This activity was higher during the acute stage of infection than after recovery. A positive and significant relationship was found between the anti-ssDNA activity and the IgM levels but not with IgG, IgA or PA titres. Speckled antinuclear antibodies (ANA) were also observed in sera from 43.8% of the individuals and the mean ssDNA activity was higher in these ANA positive patients. Conversely anti-dsDNA antibodies could not be detected by any of the tests performed. This preferential production of anti-ssDNA Ab and not anti-dsDNA Ab is additional evidence that the autoantibodies observed in malaria infection are not a consequence of a generalized and non-specific polyclonal activation.

Adolescent↗
PubMed1984

Normal frequency of anti-thyroglobulin antibodies in hyperendemic areas of malaria: relevance to the understanding of autoantibody formation in malaria.

Sera from 280 inhabitants from the Upper-Volta villages of Donsé and Oursi were screened for the presence of anti-thyroglobulin antibodies (anti-Tg Ab) by the classical passive haemagglutination technique. Precipitant malarial antibodies and immunoglobulins (IgG, IgA, IgM) levels were concomitantly evaluated. Although 90% of the individuals studied had antibodies against malaria, a disease known to be associated with autoantibody (auto-Ab) production a normal frequency of anti-Tg Ab was observed in both Donsé and Oursi villages. This normal frequency of anti-Tg Ab contrasting to the previously reported increased frequency of other auto-Ab in individuals exposed to malaria, is additional evidence that the auto-Ab production that takes place during malaria infection is not the result of a generalized and non-specific activation of autoreactive cells by parasite derived mitogens.

Adolescent↗
PubMed1984

A screening of serological syphilis in Mauritania.

A survey aiming at assessing the frequency and the distribution of serological syphilis has been carried out on a sample of 6049 subjects aged 6-18 years in Mauritania. 33.4% of the samples had a reciprocal titer of 150 or more as determined by means of an immunofluorescence technique. However, frequencies in the different villages ranged from 7.5 to 47.6% and were strongly associated with the percentage of Black elements in the community. A significant difference was found between the age-groups 6-13 and 14-18, with a mean increase of 56%. These results suggest that an intervention program might be necessary in Mauritania.

Adolescent↗
PubMed1983

Specificity of auto-antibodies in malaria and the role of polyclonal activation.

Sera of 173 individuals living in a malaria endemic region in Upper Volta (Donsé village) were screened for the presence of 14 auto-antibodies by the indirect immunofluorescent and/or passive haemagglutination techniques. At least one auto-antibody (AAb) was detected in sera of 72% (124 out of 173) subjects. No differences in the AAb frequency was observed in the sex or age groups. Conversely, a significant relationship between a high frequency of auto-antibodies, high malaria antibody titres and high IgM levels was observed. Antinuclear antibodies (ANA) (87% of total AAb) and particularly those of speckled pattern of fluorescence were by far the most frequently observed. Smooth muscle antibodies (SMA), heart and gastric parietal cell antibodies and thyroglobulin antibodies were found at a normal frequency. This selective increase in the frequency of one AAb (and not of others) cannot, in our opinion, result from a non-specific polyclonal activation. An alternative hypothesis involving both a specific antigenic and a non-specific mitogenic signal is proposed.

Adolescent↗
PubMed1983

Geographical and ethnical distribution of HBs antigen subtypes in Mauritania.

A survey conducted in sera from 515 black and 499 white individuals living in 8 villages of Mauritania showed an HBs Ag prevalence of 15.7%. Two main subtypes, ayw2 (34.7%) and ayw4 (63%), were found in this country which is a junction area between North and West Africa and where 2 ethnic groups are living close one to the other but with very rare cross-breeding. ayw2 was more prevalent in the driest part of the country (North) and ayw4 in the South. Analysis of the subtype distribution in each village indicates that there is no relationship between HBs Ag subtype and ethnic groups, but there is a correlation between HBs Ag subtype and the geographical location of the villages.

Adolescent↗