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O Raoul

Publications and source records attributed to O Raoul.

33 records · Page 2Linked to original sources
PubMed1984

Assignment of human phosphoribosylglycinamide synthetase locus to region 21q221.

The enzymatic activity of phosphoribosylglycinamide synthetase (GARS) has been studied in several cases of partial monosomies and full and partial trisomies 21. An excess of GARS activity was found in regular trisomy 21 with a trisomy 21/normal ratio equal to 1.55. A 0.99 ratio was found in 21q21----21pter monosomy; a 0.54 ratio was found in 21qter----21q22 monosomy; a 0.88 ratio, in 21q21----21pter trisomy, and a 1.46 ratio, in 21q22.1 trisomy. Consequently, the GARS gene locus, assigned to chromosome 21, could be localized in subband 21q22.1.

Adolescent↗
PubMed1984

[Ring chromosome 14. I. A case report on homogeneous r(14)].

A ring chromosome derived from a no. 14 was observed, without mosaicism, in a 2-month-old male with craniofacial dysmorphism, retarded psychomotor development, seizures and retinal anomalies. Serum immunoglobulins concentrations were normal.

Abnormalities, Multiple↗
PubMed1982

[X chromosome fragility and effects of trimethoprim].

Severe clinical regression was observed in a patient carrier of a fragile X after treatment trimethoprime. This prompted us to examine the effect of this antibiotic in lymphocyte cultures: a dose ranging from 13 mg/l to 53 mg/l increases considerably the frequency of the Xq27 gap in four fragile-X patients; a dose of 13 mg/l allows a normal growth, without appearance of the Xq27 gap, in 19 normal, non-carrier subjects; a dose of 82 mg/l totally inhibits cell division in 10 normal, non carrier subjects. The reversibility of the blockade was demonstrated, either by washing out the trimethoprime before the 50th hour of incubation or by adding 5-formyl-tetrahydrofolate (0.125 mg/l). It is concluded that one of the steps of monocarbon metabolism is inhibited by trimethoprime. This antibiotic, which must be avoided when treating patients carrier of the fragile X can be utilized in vitro for cytogenetic investigations.

Cells, Cultured↗
PubMed1981

[Fragile site Xq27 and metabolism of monocarbons. Significant decrease of the frequency of chromosomal gaps by treatment in vitro and in vivo].

A decrease of frequency of a gap at the extremity of the long arm of the X chromosome (fragile site Xq27) is obtained by adjonction of monocarbons precursors to lymphocytes cultures. The efficacity of the treatments is precised by the analysis of 44 629 mitoses. For the first time, in one patient, parenteral administration of 5-formyl-tetrahydrofolate lead to a clinical improvement with concomitant disappearance of the gap.

5-Hydroxytryptophan↗
PubMed1979

Evidence for a correlation between late replication and autosomal gene inactivation in a familial translocation t(X;21).

A familial translocation t(X;21)(q2700;q11) is studied. A girl, trisomic for almost all the chromosome 21, has a mildly abnormal phenotype. A second girl, phenotypically abnormal, is monosomic for the juxtacentromeric region of chromosome 21 only. A comparison of the replication pattern and of the activity of superoxide dismutase (gene located on chromosome 21) shows a clear correlation between late replication, gene inactivation and phenotype expression of chromsome 21.

Chromosomes, Human, 21-22 and Y↗
PubMed1976

[Partial trisomy of chromosome 21 by maternal translocation t(15;21) (q26.2; q21)].

A balanced reciprocal translocation, t(15;21) (q262;q21) was observed in the mother and maternal grandfather of two patients. The propositus, who received the abnormal chromosome 15 from his mother, is trisomic for the distal part of chromosome 21, and his phenotype is that of classical trisomy 21. His sister, who is trisomic for the proximal part of 21q, is slightly retarded but developmentally normal otherwise.

Child, Preschool↗
PubMedDate not supplied

[Spectral karyotyping (SKY) principle, avantages and limitations].

Banding karyotype is a routine technique, which allows the identification of numerous aneusomy and/or aneuploïdy in congenital diseases and cancers. However, this analysis fails to detect small or complex chromosome rearrangements. Molecular cytogenetic techniques like fluorescence in situ hybridization (FISH) analysis can overlap these limitations. Particularly, multicolor karyotyping by spectral karyotyping (SKY) may rectify or precise the conventional karyotype results. With two examples, we present here, the principle, the indications and the limits of this technique for constitutional and cancer chromosomal abnormalities characterization. Moreover, we present an easy way to build efficient sky probes with a best sensitivity than the probes classically used.

Adult↗