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H Nicolas

Publications and source records attributed to H Nicolas.

26 records · Page 2Linked to original sources
PubMed1982

Retinoblastoma, deletion 13q14, and esterase D: application of gene dosage effect to prenatal diagnosis.

Esterase D (ESD) gene dosage studies were performed on amniotic cells from a fetus at risk for del 13q14. The mother was a balanced carrier of an insertion in chromosome #20: 46,XXins(20;13)(p12;q1307q14.3). She had already given birth to a monosomic child with retinoblastoma (Rb) and to a phenotypically normal child trisomic for the same 13q14 segment. Both sibs displayed the expected proportionate gene dosage effects for ESD. A 153% value of ESD activity was found in the amniotic cells indicating unambiguously that the fetus was not monosomic for segment 13q14 and therefore not at increased risk for Rb. The mother delivered a phenotypically normal child who was confirmed to be trisomic for segment 13q14 by cytogenetic analysis and by gene dosage studies for ESD in cord blood cells and in lymphoblastoid cells.

Amnion↗
PubMed1981

Prenatal diagnosis of congenital enzymopenic methaemoglobinaemia with mental retardation due to generalized cytochrome b5 reductase deficiency: first report of two cases.

Prenatal diagnosis of congential enzymopenic methaemoglobinaemia (CEM) with mental retardation was performed in two fetuses at risk for generalized NADH-cytochrome b5 reductase deficiency. In the first case the enzyme activity of cultured amniotic cells was in the heterozygous to normal range. The mother delivered a normal baby with normal enzyme activity in cord blood cells. In the second case, the amniotic cells were almost completely enzyme deficient. The pregnancy was terminated, and the diagnosis of homozygous NADH-cytochrome b5 reductase deficiency was confirmed in cord blood cells, in several different tissues and in cultured fibroblasts from the aborted fetus.

Amniotic Fluid↗
PubMed1981

Prenatal diagnosis of congenital adrenal hyperplasia (21-OH deficiency type) by HLA typing.

The close genetic linkage between HLA-B and congential adrenal hyperplasia due to 21-hydroxylase deficiency permits prenatal diagnosis of an affected fetus by HLA typing of amniotic fluid cells in pregnancies at risk. Some families at risk, especially those with an affected girl with ambiguous genitalia, will only plan another pregnancy if a prenatal diagnosis is possible. After HLA typing of the index case, parents and eventually grandparents, the family were informed of the possibility of a prenatal diagnosis. Fibroblast cell lines were initiated from skin biopsies of the index cases and parents and were used as controls in the tests. HLA typing of the fetus was done on amniotic fluid cells grown in vitro using first, a microcytotoxicity test and second quantitative microabsorption test. Ten prenatal diagnoses are reported. In two cases the HLA genotype indicated an affected fetus, examination of the aborted fetuses was in agreement with the diagnosis. In one case an affected male fetus was diagnosed, the pregnancy is in progress. In seven cases an unaffected infant was predicted (four carriers and three homozygous normal infants).

Adrenal Gland Diseases↗
PubMed1981

Prenatal losses of trisomy 21.

Various cytogenetic studies of early spontaneous abortions have observed trisomy 21 in about 3% of the abortuses. Analyses of prenatal diagnosis performed during the 17th week of gestation and observations on late spontaneous abortions and perinatal deaths have also shown the importance of lethal trisomy 21 in the second half of pregnancy. From these studies, it can be estimated that at least four-fifths of conceptuses with trisomy 21 fail to survive. One important question is why the same chromosome anomaly in a zygote can lead either to an early arrest of development or to a liveborn infant. Pathologic examinations of spontaneously aborted embryos with trisomy 21 have rarely shown malformations that can explain the death of the embryo, but macroscopic and microscopic examinations of their placentas show growth retardation and hypoplasia. Analysis of in vitro growth characteristics of cell lines established from tissues of trisomy 21 embryos have demonstrated differences in cell population doubling times; this may explain variations in the developmental potentials of conceptuses with trisomy 21.

Adult↗
PubMed1980

[Methodology for HLA typing of amniotic fluid fetal cells (author's transl)].

Determination of HLA antigens can be used for prenatal diagnosis of some congenital anomalies such as adrenal hyperplasia (21-hydroxylase deficiency). This necessitates rigourous HLA typing of fetal cells cultivated in vitro. The method we have developed utilizes microcytotoxicity and quantitative microabsorption tests which have been adapted to the types of cells found in these cultures.

Absorption↗
PubMedDate not supplied

[A comparative study of the development of trisomy 21 concepti and the growth of their cells in vitro].

Children with trisomy 21 are only a part of conceptuses with this anomaly which leads mainly to early arrests of development. Growth retardation of embryo and placenta are the main characteristics of these abortuses. Cell lines were established from tissues of trisomics 21 of different types of evolution (early spontaneous abortions, abortions after prenatal diagnosis, stillbirths and newborn-infants). Differences in the in vitro growth characteristics of these cells have been evidenced. They may explain the variations in the developmental potentials of trisomy 21 conceptuses.

Cell Line↗