Biomedical subjects

F Boillot

Publications and source records attributed to F Boillot.

13 recordsLinked to original sources

PubMed2002

The Perseus Exobiology mission on MIR: behaviour of amino acids and peptides in Earth orbit.

Leucine, alpha-methyl leucine and two peptides were exposed to space conditions on board the MIR station during the Perseus-Exobiology mission. This long duration space mission was aimed at testing the delivery of prebiotic building blocks. During this mission, two amino acids (leucine and alpha-methyl leucine) and two peptides (leucine-diketopiperazine and trileucine thioethylester) were exposed in Earth orbit for three months. Basalt, clay and meteorite powder were also mixed with the samples in order to simulate the effects of potential meteorite protection. Analysis of the material after the flight did not reveal any racemization or polymerisation but did provide information regarding photochemical pathways for the degradation of leucine and of the tripeptide. Amino acids appeared to be more sensitive to UV radiation than peptides, the cyclic dipeptide being found to be as particularly resistant. Meteorite powder which exhibits the highest absorption in Vacuum UltraViolet (VUV) afforded the best protection to the organic molecules whereas montmorillonite clay, almost transparent in VUV, was the least efficient. By varying the thickness of the meteorite, we found that the threshold for efficient protection against radiation was about 5 microm. The possible exogenous origin of biological building blocks is discussed with respect to the stability to the molecules and the nature of the associated minerals.

Bentonite↗

PubMed1998

Delivery of extraterrestrial amino acids to the primitive Earth. Exposure experiments in Earth orbit.

A large collection of micrometeorites has been recently extracted from Antarctic old blue ice. In the 50 to 100 micrometers size range, the carbonaceous micrometeorites represent 80% of the samples and contain 2% of carbon. They might have brought more carbon to the surface of the primitive Earth than that involved in the present surficial biomass. Amino acids such as "-amino isobutyric acid have been identified in these Antarctic micrometeorites. Enantiomeric excesses of L-amino acids have been detected in the Murchison meteorite. A large fraction of homochiral amino acids might have been delivered to the primitive Earth via meteorites and micrometeorites. Space technology in Earth orbit offers a unique opportunity to study the behaviour of amino acids required for the development of primitive life when they are exposed to space conditions, either free or associated with tiny mineral grains mimicking the micrometeorites. Our objectives are to demonstrate that porous mineral material protects amino acids in space from photolysis and racemization (the conversion of L-amino acids into a mixture of L- and D-molecules) and to test whether photosensitive amino acids derivatives can polymerize in mineral grains under space conditions. The results obtained in BIOPAN-1 and BIOPAN-2 exposure experiments on board unmanned satellite FOTON are presented.

Aluminum Silicates↗

PubMed1998

The cost of tuberculosis to patients in Sierra Leone's war zone.

OBJECTIVE: To evaluate how the extreme poverty of the patients and the poor salaries of the staff combined to increase the cost of treatment to patients within the subsidised national tuberculosis programme in Sierra Leone. DESIGN/SETTING: From September to December of 1994, semi-structured interviews were conducted with 72 patients and 17 staff of the National Leprosy and Tuberculosis Control Programme of Sierra Leone, a screening and treatment programme funded by international donors. RESULTS: Although some extra costs were indeed incurred within the subsidized national tuberculosis treatment programme, they were much lower than those incurred during the pre-programme period when the patients sought intermittent help from a wide range of traditional and biomedical sources within the plural healing continuum. The national politico-economic crisis, and the consequent poverty of most patients, impeded compliance with and sustainability of treatment, even within the formal subsidised treatment programme. CONCLUSIONS: More money was spent by patients on treatment in the months/years preceding entry into the national tuberculosis programme. Many factors retarded entry, including poor communications, misinformation, malpractice by health professionals, and displacement resulting from chronic internal warfare. The war intensified all factors that predispose to tuberculosis and retarded access to treatment. Supra-programme cost, or 'corruption,' was minimal due to the poverty of health professionals, with a few salient exceptions.

Antitubercular Agents↗

PubMed1997

Prevalence of the human immunodeficiency virus among patients with tuberculosis in Sierra Leone, established from dried blood spots on filter paper.

SETTING: Sierra Leone National Tuberculosis Programme. OBJECTIVE: To evaluate serological testing in field conditions of dried blood spots (DBS) on filter paper for unlinked surveillance of human immunodeficiency virus (HIV) associated tuberculosis. DESIGN: DBS were first evaluated against sera in 359 consenting patients on the capital city's District Tuberculosis Register (DTR). DBS eluates were tested with repeated ELISA using different antigens. Serum samples were tested with ELISA and confirmed with LIA. The cost was compared with that of rapid/simple tests on whole blood. In a second phase, DBS were applied to an unlinked countrywide serosurvey of 582 patients from the DTRs. RESULTS: The specificity of DBS for HIV-1 and HIV-2 was 100% and sensitivity was 100% and 87.5%, respectively. The cost of the strategy was half that of rapid/simple tests on whole blood. In 1995, HIV-1 associated tuberculosis seroprevalence was 2.41%. CONCLUSION: The proposed method for the surveillance of HIV-1 associated tuberculosis in Africa is simple, cheap and accurate. Further investigations are necessary to evaluate its sensitivity for HIV-2, and to study the epidemiology of HIV-2 in Sierra Leone.

AIDS Serodiagnosis↗

PubMed1996

Leprosy among the Limba: illness and healing in the context of world view.

The study analyzes the traditional beliefs and practices concerning leprosy of the Limba people of Sierra Leone. It shows that this dialectally diverse ethnic group has two views of leprosy and its cause, and two varieties of stigma associated with the disease. The Limba have abandoned their traditional treatments for leprosy in response to an effective leprosy control programme, but retained their traditional world view, including its definition of illness, which holds a person seriously ill only when he has severe pain or disability. Thus, they seek treatment from the programme, but often at a relatively advanced stage of the disease. The study shows that the Limba have reinterpreted the notion of 'germs' as introduced by medical workers, and that leprosy control workers have their own misunderstandings of Limba beliefs and practices. The study points the way to improved communication between leprosy workers and Limba patients by focusing on the points at which their views differ, and by identifying concepts within Limba world view that can be adapted by leprosy workers to help convey their message. The study emphasizes the importance of world view as a key to understanding patient attitudes and behaviour in developing countries, and to making valid cross-cultural comparisons, but notes that it can take years for an investigator to understand the world view of a particular culture. It argues that in short-term research projects there is an advantage to working with an anthropologist who has in-depth knowledge of the culture, but who may not be a specialist in medical anthropology.

Anthropology, Cultural↗

PubMed1996

[Irreductible congenital dislocation of the hip at birth].

BACKGROUND: Rare congenital dislocation of hip (CDH) (0.03 for 1,000 births) are irreducible at birth; they are named teratologic in literature. However some of them are isolated without any pathological context, having a postural origin or due to an underlying disease. PATIENTS: Seventeen dislocated hips, irreducible at birth, were seen in 12 infants and included in this study. Clinical examination of these neonates was normal with the exception of signs of CDH. Postural abnormalities such as pes calcaneus, genu recurvatum, torticolis were seen in ten infants but none of the 12 had any manifestation of neurologic, dystrophic or malformative disease. However, manifestations of a disease able to explain the CDH such as congenital myopathy, cutis laxa, cortical atrophy, Klinefelter syndrome, appeared within the following months in four infants. Treatment of these CDH started in every case by an attempt of reduction by continuous traction and was efficient in eight cases. A redislocation occurred for four hips and this treatment was uneffective for five hips. Finally seven hips had to be treated by open reduction. Reduction was maintained for nine hips after closed treatment (one of them after a redislocation and a second time of orthopaedic treatment). One hip is still dislocated after failure of closed treatment. Stabilisation of the reduction was necessary by pelvic and/or femoral osteotomy in majority of cases. CONCLUSIONS: Morphological modifications of hip established from X-rays and during the surgical procedure are rather related to the age of the dislocation making inappropriate the term "teratologic". The irreducible and isolated CDH can be postural in origin but as well due to a disease whom manifestations will appear lately. Their treatment, orthopaedic or surgical, is difficult and the results often disappointing.

Female↗

PubMed1995

Evaluation of a broth microdilution antifungal susceptibility test with a pH indicator: comparison with the broth macrodilution procedures.

A broth microdilution antifungal susceptibility test with a pH indicator (bromocresol purple) in a synthetic medium was evaluated. This method measures cellular activity instead of simply a change in biomass. The variations of pH caused by fungal activity were measured by changes in optical densities at 450 nm. The MICs50 obtained were compared with the MICs found by the classical broth macrodilution procedure. In most cases broth micro- and macrodilution MICs were in agreement for amphotericin B, fluconazole, flucytosine and nystatin.

Amphotericin B↗

PubMed1993