Biomedical subjects
M Niang
Publications and source records attributed to M Niang.
[Diagnosis of tuberculosis by specific DNA amplification directly in samples].
The polymerase chain reaction (PCR was used to identify M. tuberculosis in specimens from patients with suspected pulmonary tuberculosis. A segment of the IS 6110 sequence and of the Cro EL gene were amplified and identified by hybridization with specific probes labeled with peroxidase. The results are in agreement with those obtained using standard microbiological techniques or clinical criteria. The PCR method allowed the detection of M. tuberculosis in 22 out of 58 samples that were acid fast staining negative. The number of patients with at least one positive sample by PCR was much higher in the group with suspicion of tuberculosis (14/28) than in the control group (3/23). This demonstrates the possibility of using PCR technology in endemic areas for tuberculosis.
Human phagocyte respiratory burst by Mycobacterium bovis BCG and M. leprae: functional activation by BCG is mediated by complement and its receptors on monocytes.
We have measured the role of serum components on two parameters of the phagocytosis reaction: a) the chemiluminescence (CL) response associated with the oxidative respiratory burst in response to Mycobacterium bovis BCG and M. leprae, and b) the uptake of these two mycobacteria by healthy human monocytes. Pre-incubations of fresh or heat-inactivated serum or serum containing EGTA or EDTA indicate that these two mycobacteria activate the alternative complement pathway. Monoclonal antibodies against CR1 and CR3 inhibit the responses of M. bovis BCG and M. leprae, demonstrating that complement receptors mediate the phagocytosis of these two mycobacteria. Thus, complement and its receptors on the surface of the monocytes (CR1 and CR3) are important in the functional activation of phagocytosis of M. bovis BCG and M. leprae.
CCPP: antibodies to F38 polysaccharide in Mali goats.
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Anopheles pharoensis and transmission of Plasmodium falciparum in the Senegal River delta, West Africa.
1. Anopheles pharoensis Theobald was found to be the prevalent man-biting anopheline mosquito in the central area of the Senegal River delta. 2. Blood-fed females of An. pharoensis were obtained during September-December 1987 from mosquito bednets in the village of Souhloul, near the Boundoum dam, 70 km NE of St Louis. 3. Dried mosquito specimens were identified morphologically and each thorax processed using monoclonal antibody against the circumsporozoite protein of Plasmodium falciparum. 4. Five An. pharoensis out of 912 examined were sporozoite positive, while ninety-eight An. gambiae Giles sensu lato were all negative. This finding strongly supports the local importance of An. pharoensis as a malaria vector. 5. Successful use of pyrethroid-impregnated bednets against malaria transmission in this situation has helped to achieve more than 90% reduction of malaria prevalence.
[Soft chancre in Dakar (apropos of 1,585 cases)].
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[The Senegal public health code. Methodology of research and development].
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[Tuberculous lupus in an adolescent].
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[Salmonellosis in hens due to Salmonella pikine].
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Hepatosplenic alterations determined by ultrasonography in a population recently infected with Schistosoma mansoni in Richard-Toll, Senegal.
Three years after intestinal schistosomiasis had been reported for the first time in the delta of the Senegal River Basin, an ultrasonographic study was conducted on 358 subjects of the community of Richard-Toll with a proven Schistosoma mansoni infection and compared with the findings from 352 uninfected subjects of a nearby town. Periportal thickening was found in 119 subjects (33%) in only one of whom it was greater than 10 mm; liver parenchyma lesions were found in 40 subjects (11%), at about the same rate in all age groups. No correlation was found between hepatomegaly and schistosomiasis. Frequency of thickening of the omentum was significantly higher in Richard-Toll than in the control group. 11% of the Richard-Toll subjects had portal vein diameters significantly larger than the values in the control group; of those, 6% had no periportal fibrosis sign in the liver. Significantly more splenomegaly was found in the infected group, though malaria as an aetiological agent cannot be ruled out. Based on periportal alterations and parenchyma lesions only, 141 (39%) subjects in the Richard-Toll group had alterations, corresponding to the World Health Organization proposed criteria for stage I; one subject had alterations corresponding to stage II. As S. mansoni infection is still new in this area, the patho-anatomical pattern is likely to change significantly in the future.
Preliminary study of urinary schistosomiasis in a village in the delta of the Senegal river basin, Senegal.
Three years after the first cases of urinary schistosomiasis infection were reported in the village of Mbodiene, Senegal, Schistosoma haematobium eggs were found in 87% of the inhabitants of this village; 30% were heavily infected (> 50 eggs per 10 mL urine). The prevalence of infection was very high in all age groups, but children showed more intense infections. No difference between sexes was found. In the special situation of a very high prevalence, test strips for proteinuria and haematuria are not very useful for the individual diagnosis of S. haematobium infection. Six and 12 weeks after treatment with a single dose of praziquantel (40 mg/kg), S. haematobium eggs were found in 25% and 30% of the treated subjects, respectively. Bulinus globosus was identified as intermediate host, but other snail vectors may also play a role. S. mansoni eggs were found in 1% of the population. Both S. haematobium and S. mansoni are spreading in the delta of the Senegal river.
Royal Society of Tropical Medicine and Hygiene meeting at Manson House, London, 18 May 1995. The epidemiology of human schistosomiasis in the Senegal river basin.
Extensive water development has taken place in the north of Senegal over the last decade, resulting in a large increase in the amount of fresh water for irrigation. The objectives of the present study were to determine the prevalence and intensity of Schistosoma mansoni and S. haematobium in the Senegal river basin (SRB), and to ascertain the distribution of the snail species acting as intermediate hosts for both species of schistosomes. The schistosomiasis survey started in January 1994 and was completed in March 1995. Compared to studies before the construction of the Diama dam, there was a significant increase in both the prevalence and intensity of urinary and intestinal schistosomiasis in the human population in parts of the SRB. From the 9014 people who were registered from 180 villages and 4 towns (10 districts), 7750 were examined. S. mansoni was found in the lower valley (lower delta-Senegal river, lower delta-Lampsar river, upper delta, and diéré) but not in the middle valley. The mean prevalence ranged from 4.4% in the lower delta-Senegal River to 71.8% in the zone of Lac de Guiers, where prevalence and intensity of infection were higher on the eastern side of the lake (81.3% with a mean number of 2088 eggs/g of faeces) compared with the western side (50.3% with a mean 1111 eggs/g). S. haematobium was recorded throughout the area of study, ranging from a mean prevalence of 0.37% in diére (lower valley) to 41.5% in the lower valley (Lampsar river), where the mean egg count was 313/10 mL of urine. Physical and chemical changes to the environment have favoured the spread and increase in the populations of freshwater snails. The only snail involved in the transmission of S. mansoni was Biomphalaria pfeifferi. Five species of bulinid snails were present--Bulinus globosus, Bu. umbilicatus, Bu. senegalensis, Bu. forskalii and Bu. truncatus--but only the first 3 species were involved in the transmission of S. haematobium in the lower and middle valleys.
Four years' follow-up of hepatosplenic morbidity in a recently emerged focus of Schistosoma mansoni in northern Senegal.
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The ISOBM TD-7 Workshop on hCG and related molecules. Towards user-oriented standardization of pregnancy and tumor diagnosis: assignment of epitopes to the three-dimensional structure of diagnostically and commercially relevant monoclonal antibodies directed against human chorionic gonadotropin and derivatives.
The ISOBM TD-7 hCG Workshop was established to characterize the molecular epitope structure and specificities of a panel of diagnostically relevant monoclonal antibodies (MAbs) directed against human chorionic gonadotropin (hCG) and its derivatives, and to consider how this information could be used to improve comparability of immunoassay results for these analytes. In this multicenter study, 27 MAbs have been characterized in detail as to their main and fine specificities by direct binding-, competitive- and sandwich-RIA, -ELISA, BIAcore and Western blotting. Antigens used in the study included the upcoming first WHO reference reagents for immunoassay, i.e. nick-free hCG (hCG), nicked hCG (hCGn), hCG alpha-subunit (hCGalpha), hCG beta-subunit (hCGbeta), nicked hCG beta-subunit (hCGbetan), hCG beta-core fragment (hCGbetacf), synthetic peptides of hCGbeta C-terminal peptide (hCGbetaCTP), and homologous hormones, luteinizing hormone (LH) and subunits (LHbeta) from various species. Correct classification of blinded internal controls demonstrated the reliability of the MAb referencing approach. Three-dimensional molecular epitope assignment was possible in many instances by comparing immunoreactivity of the ISOBM MAbs (n = 27) to a large panel of MAbs (n = 18) previously well characterized in the Innsbruck (P.B.) and Paris (J.M.B.) laboratories. All three major antibody specificities (alpha, n = 1; beta, n = 21; alphabeta, n = 5) were represented in the TD-7 MAb panel. HCGbeta MAbs could further be subdivided into (i) those recognizing hCGbeta only (epitopes: beta(6), n = 1; beta(7), n = 2; beta(14), n = 1) and (ii) those recognizing hCGbeta + hCG (beta1, beta2, beta4, beta5, n = 10; beta8 and beta9, n = 9). Members of the latter group were specific either for hCG + hCGbeta + hCGbetacf (beta1, n = 3) or hCG + hCGbeta + hCGbetaCTP (beta8, n = 6; beta9, n = 1) or in addition to hCG + hCGbeta + hCGbetacf recognized hLH/hLHbeta to a minor (beta2, n = 3; beta4, n = 3) or similar degree (beta5, n = 1). Epitopes were (i) located on the first and third loops protruding from the cystine knot of hCGbeta (beta2-beta6, aa hCGbeta20-25 and 68-77), (ii) presumably centered around the knot itself (beta1), or (iii) on hCGbetaCTP (epitope beta8 = hCGbeta141-144, beta9 = hCGbeta113-116). The ISOBM panel of MAbs represents all major epitope specificities suitable for the design of specific sandwich immunoassays. High analyte variability in serum and urine during the course of pregnancy and tumor development favors certain epitope combinations. For routine diagnostic purposes, assays recognizing a broad spectrum of hCG/hCGbeta variants such as hCG + hCGn + hCGbeta + hCGbetan + hCGbetacf + -CTPhCG + -CTPhCGbeta may be useful. Low cross-reactivity against related glycoprotein hormones (e.g. hLH) and their derivatives is mandatory. These criteria are best met by combinations of MAbs directed against epitopes located around the cystine knot (beta1) and against those encompassing the top of loops 1 and 3 on hCGbeta (beta2, beta4). The first WHO reference reagents for immunoassay of hCG and hCG-related molecules being prepared by the IFCC should facilitate characterization of what assays for 'hCG' are measuring. The next step towards improving between-laboratory comparability of measurements of hCG/hCG derivatives in pregnancy and oncology is provided by results of this TD-7 Workshop.
Immuno-epidemiology of Schistosoma mansoni infections in a recently exposed community in Senegal.
Schistosoma mansoni was introduced in the Senegal basin around 1988, due to man-made ecological changes. Since 1991, we investigate a recent but very intense focus, Ndombo, a village near the city of Richard Toll where the outbreak was first described. Four cohorts, each a random sample (+/- 400 subjects each) from this community, were examined and followed up after treatment, starting at 8 month intervals over a 2-year period. Each cohort is examined parasitologically (Kato-Katz), clinically, serologically (circulating antigen and antibody profiles); treated with praziquantel 40 mg/kg; followed up 6-10 weeks, one and two years after treatment; and monitored for water contact patterns and local snail densities. In the first cohort, the prevalence was 91%, with a mean egg count of 663 epg. Prevalences are near 100% in all age groups, but egg counts decline strongly in adults. Antigen detection in serum and urine confirmed that the egg counts genuinely reflect variations of worm burdens, not e.g. of worm fecundity. This is surprising, as in this focus acquired immunity in adults should not have yet developed according to current hypothesis. The antigen detection assays (CAA/CCA) showed high sensitivity and quantitative power, and promising perspectives as a research tool and possibly as a method for non-invasive diagnosis and screening in urine. Epidemiological in subsequent cohorts were highly similar, although seasonal variations were observed possibly due to transmission fluctuations. Anti-AWA and anti-SEA IgE levels increased with age, while IgG4 peaked in the age-group 10 years and correlated well with egg counts.(ABSTRACT TRUNCATED AT 250 WORDS)
Epidemic typhus imported from Algeria.
We report epidemic typhus in a French patient returning from Algeria. The diagnosis was confirmed by serologic testing and the isolation of Rickettsia prowazekii in blood. Initially the patient was thought to have typhoid fever. Because body lice are prevalent in industrialized regions, the introduction of typhus to pediculosis-endemic areas poses a serious public health risk.