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O Bera

Publications and source records attributed to O Bera.

14 recordsLinked to original sources
PubMed2003

Genetic and functional studies in multiple sclerosis patients from Martinique attest for a specific and direct role of the HLA-DR locus in the syndrome.

Among candidate genes involved in multiple sclerosis (MS) genetic susceptibility, MHC genes and particularly HLA-DRB1*1501-DQB1*0602 haplotype play a major role. Based on the strong linkage disequilibrium observed in Caucasians between DRB1*1501 and DQB1*0602 alleles, it is still impossible to draw a firm conclusion about the DRB1 or DQB1 locus involvement. In order to address this issue a strategy associating a genetic and a functional approach was conducted in a population of-non-Caucasian MS patients. We observed that in Martinicans (55 MS and 100 controls), the DRB1*15 and DRB1*07 alleles were positively associated with the disease. However in Martinicans the most common DRB1*15 subtype was *1503 and not *1501. Moreover, in Martinicans, the frequency of DQB1*0602, found in association with other DRB1 alleles than DRB1*15 (42% of DQB1*0602 haplotypes), was not increased in DRB1*15-negative MS patients, suggesting a neutral role of DQB1*0602 in MS genetics. In a second step, we demonstrated the capability of the DRB1*1503 allele associated with MS in Martinicans to present the immunodominant autoantigen MBP 85-99 peptide to a DRB1*1501 restricted MBP specific T cell line. Interestingly, structural features of DRB1*1501 or DRB1*1503 molecules are in good fit with the hypothesis that *1501 and *1503 molecules may act similarly in MS development by presenting the same immunodominant MBP peptide. On the whole, our results show a prominent role of the DRB1 locus (DRB1*1501 and/or DRB1*1503 alleles) in the immunodominant MBP 85-99 peptide presentation to genetically different MS patients and suggest a neutral role of the DQB1 encoded molecule in MS susceptibility.

Alleles↗
PubMed2001

MS and neuromyelitis optica in Martinique (French West Indies).

BACKGROUND AND OBJECTIVE: A population-based study is reported of MS in French Afro-Caribbeans (FAC) in Martinique. FAC are descendants of interracial mating that occurred between French Caucasians and black Africans in the 17th and the 18th centuries. METHODS: The authors surveyed the entire island of Martinique (area 1,128 km(2), population 357,000) between November 1997 and October 1999. RESULTS: Sixty-two patients (46 females, 16 males, ratio 2.9:1) were identified with definite or probable disease by the Poser criteria. Prevalence for all patients on December 31, 1998, was 17.4/10(5) (95% CI 13.1 to 21.7) and 14.3/10(5) (95% CI 10.4 to 18.2) for clinically definite cases (n = 51). Age range of patients on prevalence day was 17 to 73 years (mean +/- SD 39 +/- 11.3 years). Mean age at onset was 31.2 +/- 11 years. Overall, 9.7% had primary progressive disease and 19.4% had benign MS. A low proportion of definite and probable MS cases had oligoclonal bands in CSF (50.9%). Seventeen patients, 13 of whom were alive on prevalence day, had a relapsing form of neuromyelitis optica. CONCLUSION: The island of Martinique appears to have a low to medium prevalence of MS. MS was almost unknown in FAC in Martinique until the late 1970s. The apparent recent increase may be explained by improved recognition of patients, increased availability of MRI for diagnosis, increased disease awareness among physicians, increased survival of MS patients, or an actual increase in disease frequency.

Adolescent↗
PubMed2001

[The role of yaws in the serologic screening of treponematoses in blood donors in Martinique].

Using TPHA instead of VDRL for syphilis blood-screening since 1995 showed an important increase of positive blood donors in Martinique. Yaws, another treponema disease, has been present on the island until 1975-1980. Usual tests are unable to identify which type--venereal or non venereal--of treponema is involved. Our study, carried out from January 1995 to May 1999, compares actual serological and epidemiological characteristics of TPHA reactive donors to former studies. In our results, the frequency of reactive TPHA is about 1.04% in blood donations. Donors are carrying serological tracks of a past treponema disease with very low rate of antibodies, sometimes linked to yaws. Among donors aged 18 to 30, prevalence is low and is going to become similar to the rate observed in Continental France. This means that this problem will disappear in new donor generations. We suggest the possibility for them to continue blood donation, if their personal preliminary enquiry fits the admission criteria for blood giving.

Adolescent↗
PubMed2001

HLA class I and class II allele and haplotype diversity in Martinicans.

The Martinican population is mainly the product of admixture between African people and French Caucasians. The aim of the present study is to investigate at the DNA level the polymorphism of HLA class I (HLA-A, HLA-B) and class II (HLA-DRB1, DQB1 and DPB1) genes in a population of 100 Martinicans. Allelic distributions and interlocus linkage disequilibria were compared to those observed in a French Caucasian population and in African or North American African populations. Our data revealed a higher degree of polymorphism in Martinicans than in Caucasians and showed a prominant contribution of African origin in the admixed genetic feature of this population. African characteristic alleles were significantly represented in Martinicans: A*30, *33 *34, *66, *74, *8001, B*1510, *35, *42, *53, DRB1*0302, *0804, *1202, *1304, *1503, DPB1*0101, *1701, *1801, *3901. Moreover a higher diversity of A*-B* and DRB1*-DQB1* associations was observed in Martinicans compared to Caucasians which also reflects the African genetic background of this population. In the whole, using PCR-based genotyping methods for HLA class I and class II loci, this study allows a preliminary description of HLA allele distribution in this Caribbean island and gives new elements which may be helpful in the anthropologic field as well as in HLA and disease association studies.

Africa↗
PubMed1999

Drug resistance mutations among HIV-1 strains from antiretroviral-naive patients in Martinique, French West Indies.

We report on the frequency of genetic mutations associated with drug resistance in antiretroviral treatment-naive patients from Martinique (French West Indies), where zidovudine (ZDV) has been available since 1987 and where combination therapy developed simultaneously with its use in continental France. Genotypic resistance was studied in plasma HIV RNA from samples collected between 1988 and 1998 from 70 antiretroviral-naive study subjects, half presenting with either primary infection or documented seroconversion. A line probe assay (LIPA) was used to detect substitutions on the reverse transcriptase (RT) codons 41, 69, 70, 74, 184, and 215. Direct sequencing was used to complete the data for RT codons which were uninterpretable by LIPA. Of these patients, 17 harbored mutated viruses with one or more mutations in the RT gene codons analyzed. ZDV resistance mutations T215Y/F, M41L, and K70R were found in 2, 5, and 12 individuals, respectively. Mutant strains L74V (didanosine [ddI] and dideoxycytidine [ddC]) were detected in 3 patients and M184V (lamivudine/ddI/ddC) in 4 patients. However, pure mutant results at one or more codons of interest were observed in only 5 (7%; 95% confidence interval [CI], 1%-13%) patients, all involving ZDV resistance. One carried both mutations T215Y and M41L known to confer a high degree of phenotypic resistance to ZDV. Among a subgroup of 28 patients with a timepoint of infection after 1995, 24 [86%; approximately 95% CI, 73%-99%) presented with a wild-type pattern. The significance of the high prevalence of mixed patterns observed in drug-naive patients remains unclear. However, the frequency of primary mutant genotypes associated with high levels of drug resistance is low in Martinique and in this study we did not observe any currently increased tendency in this frequency.

Anti-HIV Agents↗
PubMed1999

Seroindeterminate patterns and seroconversions to human T-lymphotropic virus type I positivity in blood donors from Martinique, French West Indies.

BACKGROUND: Screening for human T-lymphotropic virus type I (HTLV-I) antibodies in volunteer blood donors has been systematic in the French West Indies since 1989. Western blot-indeterminate results are commonly obtained. The significance of these indeterminate serologic patterns in HTLV-I-endemic areas is still unclear. STUDY DESIGN AND METHODS: During a 2-year period, 9759 blood donors were tested for HTLV-I antibodies. The epidemiologic features of HTLV-I-seropositive, -seroindeterminate, and -seronegative donors were compared. A lookback investigation was performed for the HTLV-I-seropositive donors, and the HTLV-I-seroindeterminate individuals were followed up. RESULTS: Thirty-nine donors (0.4%) were HTLV-I seropositive and 49 (0.5%) were seroindeterminate. The age and sex ratio characteristics of the seroindeterminate donors are divergent from those of the HTLV-I-seropositive group and are more like those of the seronegative population. However, during the study period, three cases of seroconversion after an initial seroindeterminate profile were reported. Two cases were detected through follow-up of 38 HTLV-I-seroindeterminate donors over a mean of 8 months (2-24 months). The third seroconverter belonged to the HTLV-I-seropositive group and was identified through lookback investigation. This case is atypical, with p19 reactivity for several months before HTLV-I seropositivity. CONCLUSION: These findings indicate that, although HTLV-I-seroindeterminate donors mainly are HTLV-I-noninfected, the rate of seroconversion in a repeat blood donor population from an endemic region must be taken into consideration. Moreover, the case of delayed seroconversion observed in this study suggests the difficulty of counseling seroindeterminate blood donors in endemic regions.

Adult↗
PubMed1999

Infection with GB virus C/hepatitis G virus among blood donors and hemophiliacs in Martinique, a Caribbean island.

GB virus C/hepatitis G virus (GBV-C/HGV) RNA was detected by reverse transcription-polymer- ase chain reaction with primers derived from the nonstructural region 3 (NS3) in 9 (4.1%) of 221 blood donors and 2 of 20 (10%) hemophilia patients in Martinique, French West Indies. Anti-E2 antibodies were found in sera from 33 (14.9%) of the blood donors and 5 (25%) of the hemophiliacs. None of the subjects was positive for both GBV-C/HGV RNA and anti-E2. Among the 20 hemophiliacs, 12 (60%) had anti-HCV antibodies and 7 (35%) were positive for HCV RNA by PCR. All patients positive for HCV markers belonged to the group of 13 patients exposed previously to blood factor concentrates that were not activated virally. Nucleotide sequences of the 5'-untranslated region (5'UTR) of the GBV-C/HGV genome were obtained for the 10 NS3 PCR positive samples. Phylogenetic comparison of these isolates with reference isolates published previously showed a strong homology with European and American GBV-C/HGV strains, 8 isolates belonging to the genotype 2a and 1 isolate to the type 2b. The isolate from 1 blood donor was identified as subtype 1a, indicating the presence of West African type strains.

5' Untranslated Regions↗
PubMed1996

Assessment of qualitative functional parameters of stored red blood cells from donors with sickle cell trait (AS) or with heterozygote (AC) status.

We have compared the storage quality of three groups of 10 red blood cell concentrates of the AA, AS and AC haemoglobin phenotype. The 30 samples were drawn on CPD on day 0, and were centrifuged 6 hours later. Leukocytes were removed on D1 and the samples were kept at +4 degrees C for 42 days in SAG-mannitol. Viability tests were performed using a series of in vitro tests, including: ATP, 2,3-DPG, K+, glucose, lactic acid, pH, osmotic fragility tests and erythrocytic morphology determination. Results demonstrated a good functional quality for AS and AC haemoglobin RBCs. Higher 2,3-DPG levels were found in Hb AS and Hb AC. A lower osmotic fragility in Hb AC and AS RBCs versus Hb AA was observed; no significant difference was found in terms of ATP levels and other parameters. In addition no variation in S and C haemoglobin levels and no sickling were observed. In conclusion, these results indicate an overall good quality for haemoglobin AS and AC RBCs. Further in vivo studies must now be performed in order to confirm the transfusional quality of haemoglobin AS and AC RBCs.

2,3-Diphosphoglycerate↗
PubMed1996

Ocular manifestations in patients with HTLV-I associated infection--a clinical study of 93 cases.

The purpose of this study was to confirm that ophthalmological features seen in patients in Martinique, French West Indies, could be linked to infection by HTLV-I. The authors studied 93 HTLV-I infected patients divided into 70 patients with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) and 23 asymptomatic HTLV-I carriers. They did a complete ophthalmological examination with an assessment of lacrymal secretion by means of three tests: Shirmer 1, break-up time and rose Bengal. Some patients had a biopsy of secondary salivary glands. When possible, detection of HTLV-I antibodies was carried out in the aqueous humor. In 45 of the 93 patients (48.4%) the presence of dry keratoconjunctivitis was recorded. In 22 of these 45 cases, a biopsy of the secondary salivary glands showed the presence of lymphoplasmocytoid infiltrations comparable to the glandular changes that occur with Gougerot-Sjögren syndrome. Among the 93 patients, 15 cases of uveitis were noted (16.1%) with 13 cases of anterior uveitis and 11 cases of vitritis. The inflammation was bilateral in 9 cases (9/15 = 60%). Two cases of cotton wool spots, 3 cases of abnormalities in the distribution of the retinal pigment and 7 cases of corneal lesions were also noted. Higher levels of anti-HTLV-I antibodies were detected in the aqueous humor of 3 patients with uveitis. The coexistence of dry eye (keratoconjunctivitis), uveitis and retinal microangiopathy in patients who are suffering from HAM/TSP could suggest the involvement of an autoimmune or immunological mechanism in the physiopathology of the illness.

Adult↗
PubMed1994

[Ophthalmologic manifestations in spinal cord diseases caused by HTLV-I virus. Clinical study of 30 cases].

We present the results of ophthalmologic examinations of a consecutive series of 30 patients with HTLV-I associated myelopathy. This is the first ophthalmologic prospective study reported outside the Japanese endemic area. Twenty-one of the patients (70%) had kerato-conjunctivitis sicca in addition to accessory salivary gland lymphocytary infiltration in 7. Two cases of uveo-papillitis, 1 case of cotton-wool spots and 3 cases of retinochoroidal degeneration were also observed. Moreover, an aliquot of the aqueous humour was collected from the anterior chamber in 5 patients and showed high titer of HTLV-I antibodies for the 2 patients with uveo-papillitis. We propose different hypotheses to explain the physiopathologic characteristics of these features.

Adult↗
PubMed1991

Immunoradiometric assay of pS2 protein in breast cancer cytosols.

We studied the ELSA-pS2 immunoradiometric kit (CIS Bio International) for pS2 protein assay in breast cancer cytosols according to classic validation methods. In addition, we studied correlations between pS2, steroid receptors, and cathepsin-D assays. Repeatability (CV = 1.5% to 4.8%) and reproducibility (CV = 1.6% to 4.9%) were good. The results were linearly related to pS2 concentrations between 205 and 2200 ng/L; the detection limit was 40 ng/L. The accuracy of the assay was measured by assessing recovery; analytical recoveries were near 100% throughout the standard curve. The use of different compounds for cytosol preparation (Tris 10 mmol/L or phosphate 25 mmol/L, KCl 0.4 mol/L, bovine serum albumin 1 g/L) had no effect on pS2 results. pS2 was assayed in breast tumor cytosols from 197 postmenopausal and 92 premenopausal patients. The mean value was 24 micrograms/g of protein; the median and 25th and 75th percentiles were 6, 1, and 23 micrograms/g protein, respectively. We observed a relation between concentrations of pS2 and those of estrogen and progesterone receptors, but there was no relationship between the concentrations of pS2 and cathepsin-D.

Breast Neoplasms↗