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Biomedical subjects

F Giraud

Publications and source records attributed to F Giraud.

At least 127 records · Page 7Linked to original sources
PubMed1982

X-autosome translocations: cytogenetic characteristics and their consequences.

To define the principal characteristics of X-autosome translocations, the authors present a study of 105 cases, five of which are personal observations. The autosomal pairs 15, 21, and 22 are affected by t(X-Aut) more often than would be expected. The distribution of breakpoints on the X chromosome does not differ significantly from the expected distribution. The analysis of different patterns of inactivation seems to confirm that the inactivation could occur at random, but would be followed by a cellular selection favoring the better genetic balance. An estimate of the incidence of t(X-Aut) is proposed, based upon the conclusions that only one chromosome is susceptible to translocation in meiosis in both males and females and that all affected men will be sterile, as will be 50% of women.

Chromosome Banding↗
PubMed1982

[Genetic aspects of autosomal fragile sites. Apropos of 40 Cases].

We report forty cases of congenital autosomal fragile sites, which have been analysed genetically and cytogenetically in the light of previous reports in the literature. The nature of the lesion of DNA at the fragile site is unknown. In contrast with the fragile site Xq27 there is no particular phenotype associated with autosomal fragile sites. The incidence of early spontaneous abortion and of chromosomal abnormalities in the offspring of carriers of these inherited autosomal fragile sites suggests the possibility of prenatal diagnosis.

Abortion, Spontaneous↗
PubMed1981

The effects of membrane lipid order and cholesterol on the internal and external cationic sites of the Na+-K+ pump in erythrocytes.

cholesterol depletion alters the apparent affinity of the internal cationic sites and the maximal translocation rate but not the affinity of the external cationic sites of the Na+-K+ pump in human erythrocytes. To test whether these effects were mediated by a direct cholesterol-internal site interaction or by a change in membrane lipid order, the effects of five fluidizing amphiphiles (chlorpromazine, imipramine, benzyl alcohol, sodium oleate and sodium benzenesulphonate) on the kinetic parameters of the Na+-K+ pump were determined. The cholesterol removal and all the agents used induced dose-response decreases in membrane lipid order as measured by fluorescence polarization or ESR. Positive and neutral amphiphiles mimicked the effects of cholesterol removal on the affinity of the internal sites of the pump and to a lesser extent on the maximal translocation rate. Anionic amphiphiles had no effect on internal sites, probably because they distributed preferentially within the outer leaflet on the membrane. These results indicate that cholesterol controls the affinity of the internal sites of the Na+-K+ pump by altering the membrane lipid order. In contrast, neither cholesterol depletion nor the agents used altered the affinity of the external sites of the Na+-K+ pump. This difference in sensitivity to membrane lipids order suggests that internal and external cationic sites, although borne by the same protein, are in different lipid environments.

Adult↗
PubMed1981

Alterations in human erythrocyte shape and the state of spectrin and phospholipid phosphorylation induced by cholesterol depletion.

Cholesterol depletion of erythrocytes, obtained after incubation with phosphatidylcholine vesicles, induces in most of the experiments: (1) a discocytestomatocyte transformation as observed by scanning electron microscopy; (2) a specific decrease in spectrin phosphorylation of intact erythrocytes; (3) an increase in lipid phosphorylation. It is concluded that the effect of cholesterol on erythrocyte shape is probably mediated through its action on the activity o of membrane-bound enzymes, proteases or kinases.

Cholesterol↗
PubMed1981

[Cefotaxime in childhood infections (author's transl)].

Cefotaxime was administered to 20 patients suffering from severe bacterial infections. Four were newborn babies, seven were infants, and nine were children. The infections treated included 9 bronchopulmonary infections and 6 urinary tract infections. In 9 patients, the infecting organism was identified: E. coli (3), Klebsiella (2), Staphylococcus aureus (3), and Proteus (1). Except in one case, cefotaxime was administered alone at doses of 50 to 100 mg/kg every 12 hours. The route of administration was intramuscular. 4 patients had already received unsuccessful antimicrobial therapy. All patients were clinically cured. In those with pneumonia, the clinical and radiological response was very prompt; in urinary tract infections, the temperature returned to normal in less than 48 hours. The local and general tolerance was always good. It may be concluded from these results that cefotaxime, a new parenteral cephalosporin, is especially useful and should prove particularly effective in severe infectious conditions found in pediatric practice.

Adolescent↗
PubMed1981

X-linked mental retardation with the fragile X. A study of 15 families.

The clinical and cytogenetic features of 15 families with mental retardation linked to the fragile site on the X chromosome are presented. The 15 propositi were all prepubertal, and one was a girl. Although the clinical picture varied in severity, it was sufficiently constant to suggest the diagnosis from the facial features and the encephalopathy with language retardation and disturbed behavior. Macroorchidism was not seen before puberty. The fragile X chromosome was found in seven of the nine mothers studied and in two mildly retarded sisters and has also been demonstrated in fibroblasts in eleven subjects with the abnormality.

Adolescent↗
PubMed1981

Partial inversion of the secondary constriction of chromosome 9. Does it exist?

Pericentric inversion of chromosome 9, a common abnormality, has been much studied because of its possible genetic effect. Apart from total inversion, in which the whole heterochromatic segment of chromosome 9 appears to be situated on the short arm, some authors describe partial inversion, in which the heterochromatin is found partly on the long arm and partly on the short arm. Our study indicates that firstly, the heterochromatic segment of chromosome 9 is composed of two biochemically different subunits: the heterochromatin of the centromere itself and the heterochromatin of the secondary constriction. Secondly, it suggests that partial inversion of the secondary constriction of chromosome 9 is an unusual event, as the majority of published cases can be interpreted as the result of an increase in the centromeric heterochromatin without alteration of the secondary constriction.

Centromere↗
PubMed1981

[45X/46XY/46XrY mosaic with banding and the Turner phenotype (author's transl)].

A chromosome make-up of 45X/46XY can be associated with gonadal dysgenesis, partial dwarfism and Turner-like congenital abnormalities according to Simpson's terminology, as can pure 45X. The Turner syndrome in the form of X/XY is rare. There is a double interest in the case that we report apart from its rarity; first because it has been possible to show lack fluorescence of the Y chromosome which can occur in the pathogenesis of clinical manifestations, when a third clone exists as an addition together with a ring chromosome Y. Because the risks of tumours developing are great when the caryotype includes a Y even if it is one with banding the adnexae should be removed routinely in these cases. A tumour can develop in these girls whereas there is practically no risk if the caryotype is 45X or a mosaic without a Y in it.

Child↗
PubMed1981

[Individual variability of associations between acrocentrics (author's transl)].

We studied the quantitative and qualitative variation of associations between acrocentric chromosomes in four subjects on a period of ten months; results show a definite tendency of association in a same subject, tendency which is reproducible and clear. Even though each individual has a determined rate of associations, the number of associated chromosomes and the number of associations themselves do not vary with months. Furthermore, associations do not appear at random; indeed, they have a wide spectrum of variations from one subject to the other but if we take the subjects individually, their associative rate concerning each chromosome do not change with months. Therefore, the phenomenon of association could be viewed as a biological characteristic of each individual.

Adult↗