Biomedical subjects
Publications and source records attributed to J Chevallier.
The authors report two cases of tropical sprue occurring in Guadeloupe, in the French Lesser Antilles, a region in which this disease had previously been reported only once. One of the patients was treated with quinolone (ofloxacin).
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The nuclear gene encoding the subunit epsilon of the catalytic sector F1 of the yeast Saccharomyces cerevisiae ATP synthase was cloned and sequenced. Degenerated oligonucleotide primers were constructed from primary structure data. A part of the ATP epsilon gene was amplified by polymerase chain reaction from yeast genomic DNA. From the amplified DNA sequence a nondegenerated oligonucleotide probe was constructed and used for isolating a 2040-base pair EcoRI fragment bearing the whole gene. A 186-base pair open reading frame encoding a 62-amino acid polypeptide is described. The deduced amino acid sequence was one amino acid longer than the mature protein. A null mutant was constructed. The mutant strain was unable to grow on glycerol medium. The mutant mitochondria had no detectable oligomycin-sensitive ATPase activity. The catalytic sector appeared unstable during purification but F0-subunits were still bound to F1. The mutation promoted a highly oligomycin-sensitive uncoupling of the mitochondrial respiration rate.
A peritoneal mesothelioma is described. The diagnosis was established by histological study. The clinical and radiological presentation are nonspecific. Contact with asbestos fibers is rarely reported and not obtained in this case. The clinical, radiological, histological presentations and therapeutic aspects are discussed.
The cloned FCY2 gene (strain pAB4) of the purine-cytosine permease (PCP) of Saccharomyces cerevisiae and the cloned allele fcy2-21 (strain pAB25) introduced into an S. cerevisiae strain carrying a chromosomal deletion at the FCY2 locus [Weber, E., Rodriguez, C., Chevallier, M. R. & Jund, R. (1990) Mol. Microbiol. 4, 585-596] were studied. The influence of external pH (varying over 3.5-6) has been analysed on the uptake of adenine, hypoxanthine and cytosine (Ktapp, apparent Michaelis constant and Vm) and on the binding constants of these three solutes (Kdapp, apparent half-saturation constant and Bmax, total binding sites) determined on plasma membranes. For pAB4, the variations of Ktapp and Vm were the same for the three bases, i.e. an increase in Ktapp when the pH increased and a maximum Vm around pH 5. For pAB25, Ktapp values varied in the same way and were significantly higher for the three bases than those found in pAB4. There was almost no variation of Vm for adenine, and there was a continuous decrease when the pH increased in the Vm of hypoxanthine and cytosine. Equilibrium binding measurements were performed for the three bases with plasma membrane isolated from pAB4 and pAB25. One single class of binding sites was detected. For pAB4, the affinity increased when the pH decreased for the three bases. The affinity of PCP for adenine was always greater than for cytosine or hypoxanthine. For pAB25, the same phenomenon was observed. However, the curves showing the variation of Kdapp as a function of pH were shifted towards more acidic pH values. A model was used to fit the experimental binding data obtained with hypoxanthine for the calculation of the dissociation constants of its binding to PCP and to determine the ionization constants of an amino acid involved in ligand binding. For pAB4, at acid pH, the dissociation constant was 1.7 +/- 0.4 microM. An amino acid displaying a pK of 3.8 was determined; this value was shifted to pK 4.8 when hypoxanthine was bound. For pAB25, the main effects of the mutation were a large decrease in the affinity of PCP for hypoxanthine (Kd of 14.4 +/- 4.3 microM) and a shift in the pK of the amino acid towards a more acidic pH (about 2.9). The pK of this group remained similar to the value obtained with pAB4 when hypoxanthine was bound. From these data, it is proposed that the binding of hypoxanthine and H+ is a random process.
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The FCY2 gene of the purine-cytosine permease (PCP) of Saccharomyces cerevisiae and the allele fcy2-21 have been cloned on the yeast multicopy plasmid pJDB207. The corresponding plasmids were introduced into a S. cerevisiae strain carrying a chromosomal deletion at the FCY2 locus. The resulting strains were designated pAB4 and pAB25 respectively. The pAB25 strain, which carries the fcy2-21 allele, contains four amino acid changes in the open reading frame of the PCP (Weber et al., 1989). The influence of these mutations was studied on cells by determination of the uptake constants of purine bases and cytosine [apparent Michaelis constant of transport (Ktapp) and Vmax] and on plasma-membrane preparations, by measurements of binding parameters at equilibrium [(Kd and maximum amount of binding sites/Bmax)]. For strain pAB4, the Ktapp and Vmax of uptake were almost similar for all solutes considered [1.8-2.6 microM and 8.5-10.2 nmol.min-1.(10(7) cells)-1]. The main effect of the mutations in strain pAB25 was based on a large increase in Ktapp for all ligands except adenine. Plasma membranes of each strain displayed one class of specific binding sites. Variations in Kd of 0.4-1 microM were observed for pAB4. These slight variations had no effect on the Ktapp of uptake measured for the corresponding solutes. In contrast, using pAB25 membranes, Kd increased dramatically; 2.6 microM, 40 microM and 96 microM for adenine, cytosine and hypoxanthine, respectively. These increments were correlated to variations in Ktapp of the uptake for cytosine and hypoxanthine. Therefore, we conclude that modification in the Ktapp of uptake in the strain carrying fcy2-21 allele is merely due to a modification of the binding ability of the permease for its ligands.
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Over a seventeen years period we observed 5 patients presenting with very similar lesions the equivalent of which we could not find in the literature. These were pigmented and more or less atrophic bands which exactly followed Blaschko's lines. The lesions appeared during childhood or adolescence, between the ages of 6 and 20 years and always were unilateral. In all cases they were located on the trunk where they formed a recumbent "S" pattern characteristic of Blaschko's lines. They often started 3 to 6 cm away from the posterior midline and ended precisely on the anterior midline. These bands varied in number and in 3 out of 5 cases they were associated with pigmented atrophic bands or lines on the limbs of the same side. The intensity of pigmentation and atrophy was variable. The lesions were asymptomatic and only caused a cosmetic prejudice. They were perfectly fixed, and during a 2 to 30 years observation period they remained unmodified. The five skin biopsies performed on 3 patients showed no abnormality of the epidermis other than irregular and moderate hyperpigmentation of its deep part. In the dermis, there was no distinct pigment incontinence, no inflammation and no alteration of connective tissue texture; the elastic network was invariably normal. The impression of skin atrophy was not due to true dermal hypoplasia and perhaps corresponded to atrophy of the subcutaneous cellular tissue. No biological disturbance was observed. These lesions can easily be distinguished from epidermic naevi, incontinentia pigmenti and areas of hypoplastic dermis.(ABSTRACT TRUNCATED AT 250 WORDS)
The aim of this study was to try to determine the hospital admission profiles of Spanish immigrants in France and whether differences exist between the admission patterns in this population and the autochthus French population. The study was carried out between 1984 and 1985 in all the hospitals of the "Assistance Publique-Hôpitaux de Paris". In-patients were codified by using the OTARIE system (Organisation du Traitement Automatisé de Recherche Intéressant l'Epidémiologie) based on the I.C.D. 9R. (International Classification of Diseases). Observation of the proportional morbidity rates and the standardized rates showed differences between the two populations for tuberculosis, congenital pathology, poisoning and symptoms (multi-etiological processes, poorly defined conditions and symptoms "per se"). The Spanish sample showed a greater diagnosis for tuberculosis and symptoms (psychiatric and neurological) than the French population. However, poisoning and congenital pathologies were more frequent in the latter.
8-Azidoadenine was used as a photoaffinity reagent to characterize the purine-cytosine permease of Saccharomyces cerevisiae. It is a potent competitive inhibitor of cytosine uptake and irradiation of the cells incubated with the label induced the irreversible inactivation of cytosine uptake. Addition of excess cytosine prevented this labelling which was restricted to the outer face of the plasma membrane since it was not accumulated by the cells. In the strain with the amplified purine-cytosine permease gene the maximum cytosine uptake rate was increased 4-5-fold relative to wild type without a modification of the Michaelis constant of uptake (Kt); no uptake could be measured in the deleted strain. The relative amounts of specific labelling determined for the cells and for membrane preparations were 0, 1 and 4 for the null, the wild-type and the amplified strains, respectively. One major band specifically labelled by [3H]azidoadenine, corresponding to a polypeptide with an apparent molecular mass of 45 kDa, was observed in the wild type, amplified in the strain carrying the multicopy plasmid and not detected in the deleted strain. Therefore this polypeptide corresponds to the purine-cytosine permease.
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Polyclonal auto-anti-idiotypic antibodies (AAIs), detected in antisera of rabbits immunized with acetylcholine conjugate, have already been characterized. In this paper, we report on a cytochemical application of these AAIs on skeletal muscle motor endplates of an invertebrate. We have shown that there is a non-uniformly distributed reaction in the synaptic cleft. The deposits seem to be associated with the muscular plasma membrane. The specificity of the cytochemical method is discussed. On this kind of muscle, the AAIs are able to detect, at the ultrastructural level, acetylcholine binding sites which most likely are acetylcholine receptors.
The evolution of hospitalization for patients with HIV infections in Parisian public hospitals (Assistance Publique de Paris) can be analyzed from the data base containing discharge diagnoses and from the results of a cross-sectional survey "on a given day". At present, the activity associated with HIV infection represents more than 2% of the total activity of this institution. From 1982 to 1987, HIV-associated activity increased extremely rapidly, treating patients in acute care hospitals and clinical departments and concomitantly developing home care and day hospitalizations. The latter were responsible for the substantial decrease in the average length of hospitalization. Home care and day care hospitalizations for HIV infection continued to increase during 1988, while longer-term hospitalizations decreased.
Many patients with Acquired Immunodeficiency Syndrome (AIDS) and the other forms of human immunodeficiency virus infection are treated in the Assistance Publique hospitals of Paris (AP). A cross-sectional survey to be repeated on a given day of each trimester was designed to obtain rapidly and anonymously the number of inpatients treated. A questionnaire was sent to the head of every department treating acute inpatients, asking for the number of patients with AIDS, AIDS-related Complex, pre-AIDS... and asymptomatic carriers of HIV. In 1986, a regular increase was observed from 252 (139 AIDS patients) in March to 318 (170 AIDS patients) in December. On the average, approximately two-thirds of the AIDS patients were hospitalized in three hospitals; however, their number remained stable over the year so these three hospitals' proportion tended to decrease. An estimation of the annual number of inpatients with HIV infection was drawn from the mean of the cross-sectional survey's results. This survey makes it possible to evaluate on an almost continuous basis the impact of AIDS and related conditions on hospitalization figures.