Biomedical subjects

S Chanteau

Publications and source records attributed to S Chanteau.

At least 73 records · Page 4Linked to original sources

PubMed1995

[Evolution of the Mycobacteria Laboratory of the Pasteur Institute of Madagascar from 1991 to 1994].

In 1991, the Laboratory of Mycobacteria was a small laboratory, part of the Clinical Biology Centre (CBC) of the Institut Pasteur de Madagascar: 656 pathological samples have been analysed for the account of the CBC and the National Control Programme activities. Within 4 years, the number of samples tested increased by more than threefold and the technical ability has evolved in an important way, specially for the identification and the antibiotic sensitivity testing. The scientific equipment have been modernized and the rooms surface increased by fourfold. In 1995, this laboratory was officially designated as the National Reference Laboratory for the culture, the identification and antibiogramme for the account of the National Control programme and for the private clinicians. It also participates to the tuberculosis research programmes of Institut Pasteur de Madagascar. It is associated to the Laboratory of Mycobacteria in the Institut d'Hygiène Sociale of Antananarivo which is the National Reference Laboratory for the bacilloscopy, the teaching and the supervision of the peripheral laboratories.

Academies and Institutes↗

PubMed1995

[Genetic polymorphism of M. tuberculosis strains in Antananaviro].

The genetic polymorphism of the mycobacteria of the tuberculosis complex in the city of Antananarivo was studied on 126 strains isolated from positive microscopy pulmonary tuberculosis patients. The genetic profiles established using the RFLP technic and the IS6110 marker yielded 83 clusters of 1 to 29 strains. There were 34 strains with a IS6110 unique band profile of which 29 had a band located at 1.4-1.5 kb. These strains could be differentiated using a second marker, the DR marker. 3 strains with an unique IS6110 band located at 1.8-1.9 kb were identified as M. bovis. In general, there was no evident epidemiological relationship between the patients presenting with identical profiles. In the prison of Antananarivo, the IS6110 typing of 36 strains yielded 28 clusters of 1 to 3 strains. Excepting 2 clusters showing an internal contamination, the absence of profiles specific to the jail suggests that the patients were probably contaminated before their entrance. This preliminary study shows that the RFLP profiles of M. tuberculosis, using the IS6110 and the DR markers, were polymorphic enough for using this method to study the transmission in Antananarivo.

Cluster Analysis↗

PubMed1995

[Pericardial tuberculosis in Madagascar. 23 cases].

A 56 months retrospective study, from October 1990 to May 1995, at the Centre Hospitalier de Soavinandriana in Antananarivo pointed out 29 tuberculous pericarditis among the 97 pericardial effusions discovered by the echocardiography of 5600 patients. The sex-ratio was 0,81 and the mean age 38,6 years old (+/- 14,3). Hospitalization was justified by dyspnea (18 cases), thoracic pain (18 cases), lower limbs edema (6 cases) and ascitis (3 cases). Moreover, electrocardiography showed microvoltage in 18 cases and thoracic radiography showed one heart enlargement. Even if for 15 cases a pleural effusion was associated, only 2 patients had a pulmonary image suggestive of tuberculosis. Tuberculous pericarditis has been proved by the following examinations: pericardium puncture (21 cases), pericardium and pleural biopsy (respectively 11 and 13 cases), ganglionic biopsy and search of alcohol-acid-fast bacilli in sputum: 1 case. Histologic proof has been obtained 8 times out of 9 pericardial biopsies and 6 times out of 7 pleural biopsies. Bacteriological proof has been obtained 11 times by pathological samples cultivation: twice from fresh caseous material taken from the pericardium, once from 13 pleural fluids, 5 times from 6 pericardial biopsies, 3 times from 3 pleural biopsies. The patients have been put under antituberculous treatment associated with prednisone. 20 patients have been declared cured at the end of the treatment, 5 were dead and 4 were lost out of sight. Tuberculous pericarditis has become rare in developed countries but it is still challenging in Madagascar. In spite of the antituberculous treatment associated with corticoids, prognosis is severe (evolution towards pericardial constriction death.

Adult↗

PubMed1994

Follow-up of tuberculosis patients undergoing standard anti-tuberculosis chemotherapy by using a polymerase chain reaction.

We have analysed the clearance of Mycobacterium tuberculosis in sputum specimens from pulmonary tuberculosis patients undergoing 6-month chemotherapy, using the polymerase chain reaction (PCR) and standard microbiological methods. In a group of 19 patients, 11 (58%) were smear- or culture-positive and 13 (74%) were PCR-positive before treatment. Of the 16 patients followed from 2 months after the start of treatment and thereafter, all became smear-negative and culture-negative, whereas, with PCR, 4 (27%), 2 (13%) and 1 (7%) of these patients remained positive after 2, 3 and 6 months, respectively. These results suggest the possible usefulness of PCR in monitoring the efficacy of treatment when bacteriological tests are negative, so as to identify patients with a high risk of relapse.

Anti-Bacterial Agents↗

PubMed1994

Og4C3 circulating antigen: a marker of infection and adult worm burden in Wuchereria bancrofti filariasis.

Og4C3 circulating filarial antigen was detected in the sera of 94.5% (259/274) of microfilaremic patients, 32% (239/751) of persons with presumption of filariasis, and 23% (11/48) of chronic filariasis patients. The antigen level was correlated with the microfilariae (Mf) density and patient age (P < .01). It remained stable in patients treated with microfilaricidal drugs. Og4C3 antigen, undetectable in Mf culture media, was demonstrated to be a rare somatic Mf antigen. It appears to be an excreted or secreted antigen from adult filaria. It could be used as a marker of infection and an indicator of adult worm burden.

Animals↗

PubMed1994

Ivermectin plus diethylcarbamazine: an additive effect on early microfilarial clearance.

The effects of ivermectin, diethylcarbamazine (DEC), and the combination of both drugs on levels of microfilaremia (mf) were studied in 30 male Polynesian Wuchereria bancrofti carriers. Microfilarial densities were measured 30 min (H1/2), 1 hr (H1), and 2, 4, 8, 24, and 96 hr (H2, H4, H8, H24, and H96) after supervised single doses of ivermectin plus DEC (400 micrograms/kg plus 1 mg/kg, respectively, 400 micrograms/kg plus 3 mg/kg, respectively, and 400 micrograms/kg plus 6 mg/kg, respectively), DEC (6 mg/kg) alone, and ivermectin (400 micrograms/kg and 100 micrograms/kg, respectively) alone given to six groups of five patients each. The results showed that 1) DEC alone or combined with ivermectin induced a rapid clearance of mf after drug intake; at H1/2, the number of circulating microfilariae was reduced to 16%, 8%, 28%, and 31%, respectively, of pretreatment values in the groups receiving ivermectin plus DEC (400 micrograms/kg plus 1 mg/kg, 400 micrograms/kg plus 3 mg/kg, and 400 micrograms/kg plus 6 mg/kg) and DEC (6 mg/kg) alone; 2) ivermectin alone induced a rapid increase of mf densities during the first 2 hr, followed by a sharp decrease from H4 to H96; and 3) between H8 and H96, mf clearance was almost complete with the combination of ivermectin and DEC. A comparison among groups did not show any synergistic interaction between ivermectin and DEC on the clearance of microfilaria, with the effect of each drug being additive to each another.

Animals↗

PubMed1994

[Fatal ichthyosarcotoxism after eating shark meat. Implications of two new marine toxins].

A fish poisoning involving 188 hospitalizations occurred in November 1993, in Manakara, a middle-sized town on the south-east coast of Madagascar, following the ingestion of shark. A single shark was involved in this poisoning and was identified as Carcharinus leucas. There was no unusual characteristic of this shark or its meat. The attack rate was about 100%. First clinical signs appeared within five to ten hours after ingestion. The patients presented neurological symptoms almost exclusively, the most prominent being a constant, severe ataxia. Gastrointestinal troubles, like diarrhoea and vomiting were rare. The overall case-fatality ratio was close to 30% among the 200 poisoned inhabitants. Search for similar poisoning previously reported in this area was negative, and fishermen in Manakara usually eat that kind of shark without mistrust. Bacteriological and chemical origins were eliminated. Two liposoluble toxins were isolated from the shark liver and tentatively named carchatoxin-A and -B respectively. They were distinct from ciguatoxin in chromatographic properties.

Adult↗

PubMed1994

[Mass food poisoning after eating sea turtle in the Antalaha district].

In December 1994, a mass food poisoning through ingestion of turtle affected about 60 persons, on the north-eastern coast of Madagascar. The prevailing clinical signs were digestive (nausea, vomiting, dysphagia, acute stomatitis) and might persist during several weeks. The poisoning attack rate was 48% with a lethality of 7.7%. Such accident, even if rare in Madagascar, requires a structured organization to control sea products poisoning and to set up adequate prevention measures.

Adolescent↗

PubMed1994

Genetic control of susceptibility to leprosy in French Polynesia; no evidence for linkage with markers on telomeric human chromosome 2.

Several lines of evidence have suggested a role of genetic factors in susceptibility to leprosy. In the mouse, natural susceptibility to infection with mycobacteria is controlled by the chromosome 1 Bcg locus, a region which is syntenic with a fragment of the human chromosome 2q, region q31-q37. It has been postulated that a human homolog of the Bcg gene controls susceptibility to leprosy per se, and may be located on chromosome 2q. In order to test the influence of this putative gene on leprosy per se, we performed linkage analyses in a set of seven multicase French Polynesian pedigrees, using an affected sib pair method and the LOD score method employing different modes of inheritance. Family members were typed for eight polymorphic loci on chromosome 2q: CRYGP1, FN, TNP1, VIL, DES, INH, PAX3, and UGT1A1. Our data provide evidence against the presence of a gene controlling susceptibility to leprosy per se on human chromosome 2q in the French Polynesian population.

Chromosomes, Human, Pair 2↗

PubMed1994

Og4C3 circulating antigen, anti-Brugia malayi IgG and IgG4 titers in Wuchereria bancrofti infected patients, according to their parasitological status.

This study involved 221 microfilaremic (Mf+), 302 amicrofilaremic (Mf-) antigen positive (AG+) and 1454 Mf-antigen negative (AG-) individuals living in endemic villages. Whatever the group considered, antigen and antibody titers were widely distributed. Og4C3 antigen, detected both in Mf- and Mf+ patients, was significantly higher in Mf+ patients. The Mf parasitological status did not significantly influence the antifilarial antibodies levels in the infected AG+ individuals, although IgG4 was more discriminant. In the supposedly uninfected individuals (Mf-AG-), anti-filarial IgG and IgG4 could be detected in a large proportion of the group. Og4C3 circulating antigen test was confirmed to be a good marker of active Wuchereria bancrofti infection.

Adolescent↗

PubMed1993

Ultra-rapid, simple, sensitive, and economical silica method for extraction of dengue viral RNA from clinical specimens and mosquitoes by reverse transcriptase-polymerase chain reaction.

A rapid, simple and efficient single-tube procedure is described for the isolation of dengue virus RNA from small amount of serum (10 microliters) followed by a reverse transcriptase-polymerase chain reaction (RT-PCR). Recovery of RNA is based on the lysing and nuclease-inactivating properties of guanidinium thiocyanate in the presence of silica. The silica RT-PCR can be completed within 5 hours starting from RNA extraction to agarose gel electrophoresis. All of the 63 dengue-3 culture-positive sera were RT-PCR-positive (virus titres: < 10(2) to 11(10.69.). Of 33 culture-negative acute sera from serologically confirmed dengue fever patients collected during dengue-3 epidemic, 4 were RT-PCR-positive. RT-PCR was also positive in 29 of 30 dengue-1 culture-positive sera (virus titres range: < 10(2) to 10(8.69). Dengue-1 virus was also detected in field-caught Aedes aegypti mosquitoes by silica RT-PCR.

Aedes↗

PubMed1993

Seroepidemiological survey of HTLV-I infection in French Polynesia, Cook Islands and Fiji.

Different population groups of French Polynesia, Cook Islands and Fiji were screened for Human T-Lymphotropic Virus type I (HTLV-I) antibodies. Among 1487 individuals sampled in French Polynesia, twelve were considered Western Blot (WB) indeterminate and one was considered WB-positive for HTLV-I infection. This positive subject originated from France and was a blood donor. Out of 196 Polynesians of the Cook Islands, one was WB-indeterminate. Among populations sampled in Fiji, one of 222 Melanesians was found WB-indeterminate and one of 211 Indians was WB-indeterminate.

Adolescent↗

PubMed1993

Nucleotide sequence of the first cosmid from the Mycobacterium leprae genome project: structure and function of the Rif-Str regions.

The nucleotide sequence of cosmid B1790, carrying the Rif-Str regions of the Mycobacterium leprae chromosome, has been determined. Twelve open reading frames were identified in the 36716bp sequence, representing 40% of the coding capacity. Five ribosomal proteins, two elongation factors and the beta and beta' subunits of RNA polymerase have been characterized and two novel genes were found. One of these encodes a member of the so-called ABC family of ATP-binding proteins while the other appears to encode an enzyme involved in repairing genomic lesions caused by free radicals. This finding may well be significant as M. leprae, an intracellular pathogen, lives within macrophages.

Bacterial Proteins↗

PubMed1993

The blackfly Simulium buissoni and infection by hepatitis B virus on a holoendemic island of the Marquesas archipelago in French Polynesia.

The hematophagous blackfly Simulium buissoni causes skin lesions on an island in the Marquesas archipelago that is holoendemic for hepatitis B virus (HBV). To test the hypothesis of the possible role of this fly in the transmission of hepatitis B, 506 children (age range 2-11 years) were examined for the presence of skin lesions, and attempts were made to detect HBV DNA in and on blackflies using two polymerase chain reaction methods. The mean number of skin lesions showed a positive correlation with the age of these children (r = 0.12, P < 0.05). Furthermore, it was significantly higher in the rural zone than in the urban zone (mean +/- SD 41.02 +/- 31.71 versus 17.73 +/- 13.43; P < 0.05), and showed a correlation with a higher infection rate (73.9% versus 41.3%). Of the 45 pools of 10 insects tested, HBV DNA was not detectable on the inside of the insect, but was detectable on the flies (1-10 particles/insect in three positive pools). Infection by HBV conveyed by the flies is theoretically possible, but their indirect role via the numerous skin lesions caused on children is likely to explain such a high level of transmission.

Adolescent↗

PubMed1993

Long-term efficacy of single-dose treatment with 400 micrograms.kg-1 of ivermectin in bancroftian filariasis: results at one year.

In April 1992, a safety trial was performed with a single dose of ivermectin 400 micrograms.kg-1 (IVER 400). In 37 bancroftian filariasis carriers, 6 and 12 months after IVER 400 treatment, the microfilaremia recurrences were 3.2% and 13.5%, respectively. As compared to results from other studies with diethylcarbamazine and IVER at different dosages and periodicities, the dosage of IVER 400 seems the most effective; but a yearly intake might not be sufficient.

Animals↗

PubMed1993

Low predictive value of PGL-I serology for the early diagnosis of leprosy in family contacts: results of a 10-year prospective field study in French Polynesia.

In 1983, a cohort study to follow up the family contacts of leprosy cases was implemented in French Polynesia to assess the usefulness and applicability of phenolic glycolipid-I (PGL-I) serology in a leprosy control program. A total of 1201 contacts (666 females, 535 males) have been included in the study. The IgM anti-PGL-I seroprevalence determined on the initial sera was 17%. It was significantly higher among females than males (20% vs 15%, p = 0.02). From 1983 to 1992, 4 out of 204 (2%) anti-PGL-I seropositive contacts developed the disease (1 indeterminate, 1 BT, 1 BL, 1 LL) compared with 10 out of 997 (1%) seronegative contacts (4 indeterminate, 3 BT, 1 BB, 2 TT). Of these 10 patients, only 3 (2 indeterminate, 1 BT) converted to seropositivity when leprosy was diagnosed. The risk of developing leprosy was not significantly higher among seropositive than among seronegative groups (2% vs 1%, p = 0.2). A PGL-I circulating antigen test performed on 216 selected sera at entry into the trial showed a higher antigen prevalence when the antibody level was higher. PGL-I antigen was detectable in 5 of 12 patients tested prior to diagnosis (1 LL, 1 BL, 3 indeterminate). The median time to externalize the disease was not significantly different among antibody-positive and -negative contacts (17 vs 25 months, p = 0.3). The relative risk of developing leprosy for contact individuals was 30.8 times that of noncontacts, and 15% of the total new cases detected between 1983 and 1992 emerged from the study population.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Effects of chemotherapy on antibody levels directed against PGL-I and 85A and 85B protein antigens in lepromatous patients.

IgG antibodies against antigens 85A and 85B from Mycobacterium bovis BCG, IgM antibodies against phenolic glycolipid-I (PGL-I) and circulating PGL-I antigen were measured in the serum of 11 patients with lepromatous leprosy receiving multidrug therapy (MDT). Before treatment, 6 patients were reactive to antigen 85A, 10 patients to antigen 85B, and 11 patients to PGL-I; circulating PGL-I was detected in the sera of all of them. After 2 years of MDT PGL-I antigen could no longer be detected in all of the patients, except for two who were not compliant with treatment. IgG antibodies directed against the 85A and 85B antigens and IgM antibodies against the PGL-I antigen also decreased significantly during treatment but more slowly. The determination of circulating PGL-I antigen remains the most appropriate tool for monitoring lepromatous leprosy under MDT.

Antibodies, Bacterial↗

PubMed1993

Safety trial of single-dose treatments with a combination of ivermectin and diethylcarbamazine in bancroftian filariasis.

A supervised safety trial of the treatment with a combination of ivermectin 400 micrograms.kg-1 (IVER 400) plus increasing doses of diethylcarbamazine (DEC), given simultaneously in single dose, was performed on five groups of Polynesian Wuchereria bancrofti carriers, 49 males aged 25 to 73 years, in whom microfilaremia ranged from 1 to 6,137 mf/ml. The trial was hospital-based, open, dose-escalating (1 group per week). Safety of an unchanging dose of IVER 400 and ascending doses of DEC were studied in the 5 following groups: group 1- IVER 400 plus DEC 1 mg.kg-1, 12 patients; group 2- IVER 400 plus DEC 3 mg.kg-1, 17 patients; group 3- IVER 400 plus DEC 6 mg.kg-1, 10 patients. Two control groups were included in the study, group 4- DEC 6 mg.kg-1 alone, 5 patients; group 5-: IVER 400 alone, 5 patients. Carriers were examined and questioned regarding their experience of adverse reactions, which were graded 0 to 3 according to severity, at 6, 12 and 24 hours and at 4 days after treatment. Biological examination was performed 4 days before and 4 days after treatment and included determination of microfilaremia, complete blood count, liver function tests and assessment of creatinine and urea levels. Adverse reactions were observed in 51% of 49 carriers (15 of grade 1, 8 of grade 2, 2 of grade 3). None was considered serious and they all disappeared in 2 days. The main symptoms were fever > or = 37.5 degrees C, myalgia, arthralgia, headache, asthenia, anorexia, vertigo and chills. Adverse reactions of patients were not significantly different between the five groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗