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Biomedical subjects

V Barral

Publications and source records attributed to V Barral.

16 recordsLinked to original sources
PubMed2001

Parasite (Schistosoma mansoni) and host (Biomphalaria glabrata) genetic diversity: population structure in a fragmented landscape.

Random amplified polymorphic DNA (RAPD) markers were used to quantify genetic diversity within and between 5 populations of Schistosoma mansoni within its definitive host (Rattus rattus) and the 5 corresponding populations of the snail intermediate host (Biomphalaria glabrata) from a limited endemic area of murine schistosomiasis on the island of Guadeloupe. Analysis of molecular variance (AMOVA) and canonical correspondence analysis (CCA) were used to test the significance of genetic differentiation between populations. Both methods gave similar results. Of total gene diversity, 15.1% (AMOVA) and 18.8% (CCA) was partitioned between localities for S. mansoni with an absence of association between genetic and geographical distances. Geographical localities accounted for 20.5% (CCA) of the total diversity for B. glabrata populations. The genetic distances between pairs of parasite populations were not correlated with the genetic distances between the corresponding pairs of snail host populations. Such strong patterns of local differentiation of both parasite and snail populations are consistent with predictions based on metapopulation dynamics and may have implications on host-parasite susceptibility relationship through local adaptation processes.

Animals↗
PubMed1996

Distribution of schistosome genetic diversity within naturally infected Rattus rattus detected by RAPD markers.

Random amplified polymorphic DNA markers (RAPD) were used to visualize the genetic diversity within and between infrapopulations of Schistosoma mansoni recovered from the natural vertebrate host, Rattus rattus, trapped at an insular Guadeloupean focus. Phenotypes were characterized by the sex of the parasites and by 8 polymorphic markers generated by 3 primers. Among the 212 parasite individuals recovered from 10 infected rats, 78 genotypes were characterized. All the hosts naturally infected harboured multiple parasite genotypes with a maximum diversity of 28 genotypes/host. Phenotypic and genotypic diversity calculated by Shannon-Wiener's indices and Lynch and Milligan's estimators respectively is, on average, greater within than between hosts. Considering the very low snail infection rates observed in this focus and the rapid turnover of the vertebrate hosts, our results suggest that the high mobility of the vertebrate host and/or plurimiracidial snail infections could be factors responsible for parasite genetic diversity within hosts.

Animals↗
PubMed1993

Detection of genetic diversity within snail intermediate hosts of the genus Bulinus by using random amplified polymorphic DNA markers (RAPDs).

A polymerase chain reaction-based polymorphic assay procedure (RAPD) was used to study the genetic diversity of intermediate host snails within the genus Bulinus. Genetic differentiation was detected between two closely related species: Bulinus globosus and Bulinus umbilicatus. Evidence is presented demonstrating the potential of RAPD markers for differentiating populations of B. forskalii from different countries (Cameroon, Equatorial Guinea and Ivory Coast) or from the same country (Cameroon). RAPDs may be also used to identify offspring from cross- and self-fertilized hermaphrodite bulinid snails. RAPDs provide a cost-effective and routine method for genetic studies of snails transmitting schistosomiasis and for the evaluation of diversity between snail populations.

Animals↗
PubMed1993

Genetic variability and evolution of the Schistosoma genome analysed by using random amplified polymorphic DNA markers.

The usefulness of random amplified polymorphic DNA markers (RAPD) was assayed in an attempt to discriminate among species, strains and individuals within the genus Schistosoma. Depending on the species, 40-50 arbitrary decamer oligonucleotides were used as primers to amplify total DNA by the polymerase chain reaction (PCR). An important polymorphism was observed among 5 species, allowing a phylogenetic tree to be outlined. These differences can be used for rapid and accurate identification. A limited but easily detectable polymorphism was revealed among 3 strains of a single species (Schistosoma mansoni). Minor differences were observed among individuals of a single strain. A RAPD marker allows sexual discrimination between individuals from the terminal spined-egg species group. Although a limited number of strains have been examined, the results already indicate clearly that RAPD markers constitute a powerful tool for the analysis of genetic variability. This new tool will considerably extend the information available from morphology, isozyme and limited restriction fragment length polymorphism data and opens the way to genetic analysis of these species.

Animals↗
PubMed1992

[Magnetic resonance imaging of the normal and the pathological knee in the child].

The results of magnetic resonance imaging (MRI) studies performed on the knee region of 60 children including 20 normally growing subjects are reported. In healthy children, MRI permitted to study the normal maturation of bone marrow and cartilaginous structures. The patients studied had bone tumors (11 patients), rheumatoid arthritis (8 patients), lesions of traumatic origin (7 patients), osteochondritis (4 patients), vascular and tissular dysplasia (3 patients), osteomyelitis (3 patients) and soft-tissue tumors (3 patients). In all patients, MRI showed clinically relevant abnormalities that were not detected by conventional X-rays or physical examination. MRI offers the ability to study disorders of bone, bone marrow, cartilage, menisci and ligaments in a noninvasive way. MRI has replaced arthrography of the knee and is the examination of choice in pediatric patients.

Adolescent↗
PubMed1988

MRI of hypothalamic hamartomas in children.

Eight cases of hypothalamic hamartomas (HH) diagnosed in children by clinical, biological and CT studies have been explored by MRI and compared with a control group of twenty children without hypothalamohypophyseal signs. MRI revealed the hamartoma in all cases. Its location and position relative to the floor of the third ventricle was precisely determined. The signal intensity of the lesion was identical to that of normal grey matter on T1-weighted images (300/600.28), but an hyperintense signal was observed over T2-weighted images (1800.60/120) in seven of the eight cases. These data suggest that HH are somewhat different in structure from normal brain tissue. MRI variations in signal intensity should be taken into account in the diagnostic work-up of these lesions.

Child↗
PubMed1987

[Genital tuberculosis in a 14-year-old girl].

The authors report the case of a 14 year-old girl presenting with pulmonary, adrenal and genital tuberculosis. Pelvic pain was the presenting symptom. Association of familial contamination, phlyctenular Mantoux test, apex infiltrate with a calcified nodule on chest x-ray film and numerous pelvic calcifications on plain films of the abdomen led to diagnosis. The authors emphasize the importance of the supervision of Mantoux test and the necessity of treatment of any latent primary tuberculosis.

Adolescent↗
PubMed1985

Acquired deep venous thrombosis in children.

In this study nine children with an acquired deep venous thrombosis (DVT) are discussed. The condition involved the limbs, pelvis and abdomen and was asymptomatic in five cases. Infection and long-term catheterisation were common predisposing factors. Phlebography was the most common and reliable diagnostic procedure.

Adolescent↗
PubMed1982

[Pleural mesothelioma: 3 developmental forms].

In the medical literature, there have been fewer reports on benign pleural mesotheliomas than on their malignant counterparts. We have reviewed the clinical, radiological and pathological features of mesotheliomas seen at the Hôtel-Dieu in Montreal over the past ten years. This experience leads us to postulate that there are three types of mesothelioma. The malignant form is often typical. Pedunculated lesions most often prove to be asymptomatic and benign. However, we have identified an intermediate category where the definitive nature of the mesothelioma could only be established after long term follow-up of the biological behaviour of the tumor.

Adult↗
PubMedDate not supplied

[Infectious aneurysm of the superior mesenteric artery in a 14-year-old child].

A 14-year-old girl developed an infectious aneurysm of superior mesenteric artery secondary to a bacterial endocarditis. Diagnosis was suggested by ultrasound images demonstrating a hypoechogenic structure with imparted turbulent systolic movements in superior mesenteric artery region. Diagnosis was confirmed at operation involving an obliterating endo-aneurysmoraphy.

Adolescent↗