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Biomedical subjects

M Niang

Publications and source records attributed to M Niang.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of the antineoplastic activity of mitoxantrone-L-carnitine combination therapy on an experimental solid form of ehrlich tumour in mice.

We have commenced a series of experiments to evaluate the effect of carnitine derivatives on the antineoplastic activity of mitoxantrone (MX) on various animal cancers. This report describes the therapeutic effect of MX in combination with l-carnitine (LCAR) on the growth of a solid form of Ehrlich tumour inoculated into mice. LCAR was administered subcutaneously at doses of either 200 or 100mgkg(-1) on day 6 and 13 after tumour inoculation, 1h prior to the treatment with MX. Mitoxantrone was administered intravenously at doses of 3 or 6mgkg(-1). We found that LCAR had no potentiating effect on the efficacy of MX, in terms of either slowing tumour growth or increasing the survival of mice. Nevertheless, therapeutic effects can be assumed at higher doses of both drugs based on values calculated from an index of relative hazards.

Algorithms↗
PubMed2006

Differences in circulating dendritic cell subtypes in peripheral, placental and cord blood in African pregnant women.

Dendritic cells (DC) are important for induction of primary immune responses and immunological tolerance. Changes in the frequency of DC subsets were analyzed in peripheral blood from pregnant women (mPB) and compared to placental blood (PB) and cord blood (CB). DCs were identified by flow cytometry in whole blood as lineage negative and HLA-DR-positive cells. Different DC subtypes were identified with CD123 and CD11c markers. In these data, the percentage of DC was significantly lower in mPB, PB and CB than in control women, but the absolute number of DC was higher in CB, suggesting that numbers of DC in CB do not explain the decrease of the immune response in newborn infants. Myeloid DCs (MDC) decreased in all compartments of pregnant women compared to control women, especially in mPB where MDC became lower than lymphoid DCs. An increase of less differentiated DC was observed in mPB and CB from pregnant women. DCs in pregnant women were mainly immature DC with a proportion of CD83-positive DC, identical as control women. The levels of IFNgamma, TNFalpha, IL-2, IL-4, IL-5 and IL-10 were not different in the three compartments (mPB, PB, CB). In conclusion, the phenotype and subset of DCs were different in pregnant women than in control women, suggesting a role in maintenance of immune tolerance against the fetus. The distribution of DC subsets was different in mPB, PB and CB. Their role in the regulation of immune response remains to be elicited.

Adult↗
PubMed2005

Gamma interferon-producing CD4 T-cells correlate with resistance to Mycoplasma mycoides subsp. mycoides S.C. infection in cattle.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most significant cattle disease in Africa. The control measures, which led to eradication from numerous countries are not feasible in Africa where the only prophylaxis relies on vaccination. However, the attenuated vaccines, used up to now in Africa, are of low efficiency. The development of an improved vaccine is, therefore, a necessity. The purpose of this study was to compare some immunological parameters in MmmSC-infected cattle (endobronchial versus natural in-contact infection) and assess the response in correlation with the clinical outcome (death versus recovery). Characterization of the immune parameters elicited in recovered animals, known to be refractory to new infection, will be an important step towards development of new vaccines against CBPP. A significant outcome of this study was the demonstration that all MmmSC-infected cattle developed a MmmSC-specific cell-mediated immune response. A kinetic analysis of the MmmSC responsiveness showed that the main difference between endobronchially- and in-contact infected animals was the delay before the onset of the MmmSC-specific immune response. The first MmmSC-responding PBMC sample was selected from each animal for cell phenotyping. The phenotypic analysis of this early MmmSC-induced response revealed the predominant contribution of the CD4 T-cells in all animals whereas IFNgamma was only constantly produced in recovered animals. Evolution of this early MmmSC-specific immune response was then followed by a kinetic analysis of the MmmSC-induced CD4 T-cell response and IFNgamma released. The results demonstrated that in recovered animals, the MmmSC-specific CD4 Th1-like T-cell response was maintained until slaughtering whereas in animals with acute disease, progression of CBPP was associated with a decreased ability of the PBMC to produce IFNgamma. The results led to the identification of immune parameters, which correlate with protection against CBPP and to a relevant strategy for the development of improved vaccines against this disease.

Animals↗
PubMed2002

[Fertility after ectopic pregnancy at the University Hospital in Dakar].

The aims is to evaluate fertility and medical cost about post ectopic pregnancy follow up. It is about a retrospective and descriptive study about 337 patients who have the opportunity to get a salpingectomy for an ectopic pregnancy between 1989 and 1997 at Le Dantec Gynecological and Obstetrical Clinic. After the ectopic pregnancy cure, women are followed with contraception, just time before trying to obtain another pregnancy. The studied parameters are: age, parity, socio-economical status, level of instruction, obstetrical and gynecological antecedents, Chlamydia serology, hysterosaipingography data, fertility after ectopic pregnancy, fees related to the cost of follow up after ectopic pregnancy. Data exploitation is done through an epidemiologic programme named Epi Info version 5 The average age of the patients was 27 years and that of the parity was 2.70. 87.83% of women were married. More than the half of those patients came from the suburb of Dakar. 171 patients (50.74%) were followed regularly, the other 166 (49.26%) disappeared. A Chlamydia trachomatis infection was found among 23.4% of cases. A tubal obstruction was noted in the level of the horns at 12.5 % of women. No case of maternal death was observed. Among 59 patients who wished a pregnancy, 34 ectopic pregnancy had been obtained (57.62%) in 4 month after stopping contraception and 26 cases of a new ectopic pregnancy. The expenses of medical cure after ectopic pregnancy are about 17.814 to 71,574.65 F CFA with an average of 38,689 F CFA (389.89 FF). Medical care after ectopic pregnancy raises a lot of problems: --some patients disappeared probably because of the inaccessibility of financial cost, --the high rate of Chlamydial trachomatis infection, an hypofertility after ectopic pregnancy. To combat this, we have to insist in the prevention of sexually transmitted diseases in general and of the chlamydial infection in particular. We have also to insist in the early diagnosis of the ectopic pregnancy. At last, we must set up a registre of ectopic pregnancy at the national level.

Adolescent↗
PubMed2001

Seasonality in the transmission of schistosomiasis and in populations of its snail intermediate hosts in and around a sugar irrigation scheme at Richard Toll, Senegal.

Irrigation for intensive sugar cultivation started in the early 1980s at Richard Toll, some 100 km from the mouth of the Senegal River. Infections with Schistosoma mansoni were first seen in late 1988. This study records quantitative snail surveys for over 3 years from 1992 at sites representing different habitats in and around the irrigation scheme. Populations of both Biomphalaria pfeifferi (the intermediate host of S. mansoni) and Bulinus spp. (mainly B. truncatus, the local host of S. boris) peaked in late 'spring' or early 'summer', depending on the habitat, and then remained low until the following spring', B. pfeifferi favoured smaller, man-made habitats with most transmission between May and August each year. The less abundant Bulinus spp. favoured larger natural and man-made habitats with most S. bovis transmission between April and July. S. mansoni infections were more, but S. bovis infections were less abundant than other trematodes in their respective snail hosts. Ecological changes in the early 1980s due to sugar irrigation pre-dated similar, more widespread changes in the late 1980s when the completion of dams across the Senegal River prevented seasonal rain fed floods and sea water intrusion. S. mansoni has since spread rapidly around Richard Toll. The incompatibility of the local S. haematobium strains with the dominant bulinid snails has so far prevented an epidemic of urinary schistosomiasis at Richard Toll, but the invasion of similar downstream habitats by susceptible B. globosus is worrying. The principal control measure, chemotherapy, given in the 'winter' would minimise the rate of reinfection. It could be reinforced by judicious mollusciciding within the sugar irrigation scheme but not elsewhere.

Animals↗
PubMed2001

Controlled trial of 3-day quinine-clindamycin treatment versus 7-day quinine treatment for adult travelers with uncomplicated falciparum malaria imported from the tropics.

We conducted a randomized, double-blind, placebo-controlled trial to compare a 3-day quinine-clindamycin regimen (group QC) with a 7-day quinine regimen (group Q) for the treatment of uncomplicated Plasmodium falciparum malaria in travelers returning from the tropics. A total of 55 and 53 patients in groups Q and QC were analyzed, respectively. Adverse effects were similar in both groups, although two patients in group Q had severe adverse reactions, leading to the cessation of treatment. The 28-day cure rate for the evaluated patients (per-protocol analysis) was 100% for group QC, whereas it was 96.3% for group Q (P = 0.5). The 28-day cure rate in the intention-to-treat analysis was 96.2% for group QC, whereas it was 94.6% for group Q (P = 1). There were no significant differences between the two regimens with regard to parasite and fever clearance times. Our study shows that the 3-day quinine-clindamycin regimen is well tolerated and compares favorably with a 7-day quinine treatment. This short-term regimen had previously been evaluated only in areas of endemicity. According to our results, the 3-day quinine-clindamycin regimen may be an alternative for the treatment of imported uncomplicated P. falciparum malaria in travelers returning from the tropics.

Adult↗
PubMed2000

Sex-dependent neutralizing humoral response to Schistosoma mansoni 28GST antigen in infected human populations.

The reduction of Schistosoma fecundity observed after experimental vaccination with the Schistosoma mansoni 28-kDa glutathione S-transferase (Sm28GST) antigen has been related to the inhibition of glutathione S-transferase (GST) enzymatic activity by specific antibody. The humoral immune response to the protective antigen Sm28GST and to the epitopes involved in the enzymatic site (amino acid ¿aa sequences 10-43 and 190-211) was evaluated in infected individuals before chemotherapy treatment. The capacity of the serum samples to inhibit GST enzymatic activity was assessed. Specific IgG3 response was predominant in the male population with a low intensity of infection and was associated with maximal GST inhibition. In contrast, the neutralizing activity of serum samples from women with a low intensity of infection was correlated with high specific IgA response specifically directed toward the 190-211 epitope. These results strongly support the hypothesis that GST-neutralizing IgG3 and IgA isotypes are sex dependent. The relationship of this specific acquired immune response with the level of intensity of infection is discussed.

Adolescent↗
PubMed2000

Effect of acetyl-L-carnitine on leukemia L1210 resistant to mitoxantrone.

Supportive care in tumour chemotherapy is a subject of intensive research. The complications of cytostatic therapy are a cause of extensive research of their pharmacological interactions and side effects. The immunologic and biochemical changes accompanying tumours are the factor that is most responsible for the worsening of the physiology of the host. Regimens containing carnitine and it's acetyl-derivative are used in many cases, among others even for preventing hepatotoxicity. Our hypothesis was to verify the supporting metabolic effects of acetyl-L-carnitine hydrochloride (ALC) in combined therapy with mitoxantrone (MX) and hepatotoxic cytostatic drugs including alkylating agents. This present report describes the effect of ALC in combination with MX on DBA/2 male mice bearing a transplantable L1210 leukemia resistant to MX. The criterion for evaluation of effect was the length of survival time of experimental animals. The proportional-hazards model quadratic in the drug dose (7) was used for survival time evaluation and optimal dose calculation. The hazard functions and the index of relative hazard were determined using Weibull distribution after logarithmic transformation of the entered data in each particular group. The dose-response curve was represented by a second-degree polynomial without absolute term. The combination therapy revealed that the optimal dose of ALC was 186 mg/kg s.c. This relation is shown in Fig.1. A significant effect of ALC (s.c.) in combined therapy with MX (6 mg/kg i.v.) given to animals bearing an experimental form of leukemia L1210/MX resistant to MX was proven at a level of probability p < or = 0.001. The effect of ALC in monotherapy was not demonstrable.

Acetylcarnitine↗
PubMed2000

[Serum cortisol level variations in thyroid diseases].

This work studies the thyroid disorders impact on adrenals glands by measuring total cortisol. Radioimmunoassays of thyroid hormones and cortisol were performed in 108 subjects, aged 20-52 years, with thyroid diseases. Our results show low cortisol values (80.35 nmol/L) in 4.77% of hyperthyroids, high values in 3.57% of hyperthyroids (1348.18 nmol/L) and 12.5% of hypothyroids (969.05 nmol/L). In hyperthyroidism, thyroid hormone stimulates the secretion of 11 ceto metabolites biologically inactive, unable to slow pituitary activity, inducing an increased production of endogene cortisol. Excessive catabolism can lead to the exhausting of overstimulated adrenal glands, and therefore to a decreased cortisol. In hypothyroidism, high cortisol results of increase cortisol half life and decrease of metabolic clearance. Control mechanisms often allow normal cortisol values. These alterations in functional activity of adrenal glands, seen in nearly 10% of these subjects, sometimes command a specific attitude in diagnosis and therapy.

Adrenal Glands↗
PubMed1999

Cellular immune responses of a Senegalese community recently exposed to Schistosoma mansoni: correlations of infection level with age and inflammatory cytokine production by soluble egg antigen-specific cells.

A recently reported epidemic of Schistosoma mansoni infection in Senegal provided an opportunity to study the dynamics of the development of immunity to human schistosomiasis. We report here on the cell-mediated immune response in a population of 99 females and 95 males, with particular emphasis on the relationship between intensity of infection and age. We found that the intensity of infection correlated negatively with age in females but not in males. In men and women, both Th1- and Th2-type cytokines were detected upon in vitro stimulation of PBMCs with soluble egg antigen (SEA) or soluble adult worm antigens (SWAP). In the female group, SEA-induced PBMC proliferation was associated with the production of IFN-gamma, IL-2 and IL-5, all of which correlated negatively with intensity of infection. Most cytokine production correlated positively with age. Spontaneous production of TNF-alpha, IL-6 and IL-10 was higher in the infected population than in an uninfected control group. Our results suggest that immunity to infection could be more pronounced in the female population and associated with a Th0/1 + 2 pattern of cytokine secretion mediated by soluble egg antigen (SEA).

Adolescent↗
PubMed1999

Differential serologic response to Mycoplasma ovipneumoniae and Mycoplasma arginini in lambs affected with chronic respiratory disease.

An enzyme-linked immunoabsorbent assay (ELISA) was used to evaluate the levels of antibodies to Mycoplasma ovipneumoniae and M. arginini in lambs with chronic respiratory disease. Sera were obtained from lambs in several flocks at various stages of the clinical disease and tested with sodium dodecyl sulfate (SDS)-treated M. ovipneumoniae and M. arginini whole cells and a crude capsular extract of M. ovipneumoniae as the antigens. There were low levels of antibody to M. ovipneumoniae in flocks sampled at the early stages of infection, whereas increased levels of antibody were present in lambs from flocks that had apparently recovered from the clinical disease. Slowly rising titers of circulating antibodies to M. ovipneumoniae were confirmed by sequential bleeding of lambs during the course of the clinical disease. However, antibody levels of M. arginini were more likely to increase earlier in the disease process. There was significant cross-reactivity between the 2 SDS-treated antigens in both the ELISA test and western immunoblotting. In contrast, the crude capsular extract was specific for detecting antibodies to M. ovipneumoniae.

Animals↗
PubMed1998

Occurrence of autoantibodies to cilia in lambs with a 'coughing syndrome'.

A respiratory disease of lambs that has been termed the 'coughing syndrome' has been observed in the mid-western region of the United States of America. Mycoplasma ovipneumoniae (M. ovipneumoniae) and Mycoplasma arginini (M. arginini) were routinely isolated from the respiratory tract of lambs with this disease. A high level of antibodies reactive with ovine cilia of the upper respiratory tract was detected in the sera from many of the lambs in affected flocks but not in sera of lambs from unaffected flocks. The reactivity of these antibodies with cilia was demonstrated by ELISA and confirmed by indirect immunofluorescent staining and western immunoblotting. These antibodies were predominantly of the IgG isotype. They were distinct from cold or warm agglutinins and could be absorbed from the sera with cilia but not with antigens of common bacterial pathogens of the sheep respiratory tract including M. ovipneumoniae, M. arginini, Pasteurella haemolytica, Pasteurella multocida or Neisseria ovis. In addition, their occurrence appeared to be independent of the specific antibodies to M. ovipneumoniae and M. arginini. Western immunoblotting indicated that the antibodies were directed primarily against an antigen with apparent molecular weight of 50 kDa. In one flock from which serial serum samples were collected from the same lambs over a 10-month period, antibodies to ovine cilia developed before the onset of the clinical disease and persisted for a period of several months until most of the lambs had apparently recovered. However, colonization of the respiratory tract of the lambs by M. ovipneumoniae preceded the production of these antibodies. Sequential serum samples taken from another flock, with no known history of this coughing, showed no such antibodies throughout the sampling period. It is suggested that an immunopathologic mechanism involving production of autoantibodies directed against a ciliary antigen of the lambs could be a contributing factor to the pathogenesis of this clinical disease.

Animals↗
PubMed1998

[Endobronchial tuberculosis presenting as an obstructive tumor in an HIV-1-positive patient. Apropos of a case and review of the literature].

INTRODUCTION: A rare case report of endobronchial tuberculosis is reported in an HIV-1 positive patient of black African origin. EXEGESIS: A 38-year-old woman of Guinean origin, HIV-1 positive, presented with persistent right upper lobe opacity at chest X-ray. Computerized tomography of the chest after injection confirmed this finding and revealed right laterotracheal and Barety space adenopathy. Investigations of acid-fast bacilli in the biological media were negative. Fiberoptic bronchoscopy showed endobronchial lesion on the wall of the ventral part of the right upper lobe, which had the appearance of bronchogenic carcinoma, and infiltrates in the dorsal mucosa. Biopsy of the lesion revealed granuloma formation, but no evidence of caseation necrosis. Identification of Mycobacterium tuberculosis in sputum culture helped arrive at a diagnosis of endobronchial tuberculosis similar to obstructive bronchial tumor. CONCLUSION: This case of endobronchial tuberculosis is the first described in an HIV-1 positive patient of black African origin. Mediastinal lymph node revealed by chest computerized tomography after injection could be the site of spreading of mycobacteria by fistulization of tuberculosis lymph node into the right main bronchus. Only the histology of lesions carried out during bronchial fibroscopy permitted the exclusion of endobronchial neoplasia. In addition, the sensitivity of direct microscopy for acid-fast bacilli is poor. Identification of Mycobacterium tuberculosis by sputum culture helped guide the diagnosis which was further confirmed by a good therapeutic response. This case of endobronchial tuberculosis in an immunodepressed patient underlines the difficulty in determining the etiology of pulmonary opacities.

AIDS-Related Opportunistic Infections↗
PubMed1998

Human IgE responses to rSm22.6 are associated with infection intensity rather than age per se, in a recently established focus of Schistomiasis mansoni.

In studies of schistosomasis mansoni-endemic communities, individuals with IgE responses to a 22 kD adult worm antigen (rSm22.6) suffered lower intensities of reinfection after treatment. It is of interest to define the factors that lead to the production of rSm22.6-specific IgE because it is a marker for resistant individuals and it may be involved in the development of resistance to reinfection. In endemic populations rSm22.6-specific IgE increases linearly with age. However, it is not possible to distinguish between age per se and 'history of infection' in endemic populations because individuals are exposed to the parasite at an early age. We have, therefore, quantified pre- and post-treatment isotype responses to rSm22.6 in a comparatively 'epidemic' Senegalese community where the patients were infected at different ages and where pre-treatment intensity of infection can be taken as a reasonable measure of antigen exposure. Post-treatment isotype responses to rSm22.6 correlated positively with pre-treatment intensities of infection but were not shown to be related to age. IgG1, IgG4 and IgE responses to rSm22.6 were significantly higher after treatment with the difference increasing with the pre-treatment level of infection. These results from a recently established focus of infection suggest that isotype responses to rSm22.6 are antigen-exposure dependent rather than dependent on age per se.

Adolescent↗
PubMed1998

Field isolates of Mycoplasma ovipneumoniae exhibit distinct cytopathic effects in ovine tracheal organ cultures.

Ovine tracheal ring explants were infected with four different Mycoplasma ovipneumoniae and one M. arginini field isolate and their ability to induce cytopathic effects was tested by measuring ciliary activity and intracellular calmodulin release. Infected tracheal rings showed significantly decreased ciliary activity as compared to the non-infected control rings. There were, however, marked differences between isolates in the onset and severity of the effects which correlated with their ability to produce hydrogen peroxide. Infected tracheal rings released more calmodulin than the non-infected controls. The amount of calmodulin released also varied between isolates, and somewhat reflected the degree of loss of ciliary activity in the corresponding rings induced by the different isolates. Light and electron microscopic examinations of infected tracheal rings revealed disorganisation and sloughing of the epithelium, and association of mycoplasmas only with the cilia. Following repeated in vitro passages, the organisms had reduced ability to inhibit ciliary activity which correlated with decreased hydrogen peroxide production. Addition of catalase to the organ cultures delayed loss of ciliary activity. These results suggest that M. ovipneumoniae induced ciliostasis in ovine tracheal ring explants which correlated with hydrogen peroxide production. Furthermore, these M. ovipneumoniae-induced injuries to respiratory epithelial cells could contribute to the role that this organism may play in sheep respiratory disease.

Animals↗