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J Lejeune

Publications and source records attributed to J Lejeune.

At least 55 records · Page 3Linked to original sources
PubMed1989

Correlation between the effects of rT3 and IMP dehydrogenase inhibitors on normal and trisomic 21 lymphocyte cultures.

3,3'5'-triiodothyronine (rT3) levels have been documented to be low in patients with Down syndrome but the metabolic implications of this finding remain unknown. A highly significant correlation was found between the in vitro variations of the mitotic index in lymphocyte cultures when rT3 or known inhibitors of inosine monophosphate dehydrogenase: mycophenolic acid, 6-mercaptopurine or 2-3-diphosphoglycerate were added. No significant difference was found between the response of trisomy 21 or normal lymphocytes. The finding suggests that rT3 may be a physiological modulator of inosine monophosphate dehydrogenase. The implications on cellular differentiation are discussed.

2,3-Diphosphoglycerate↗
PubMed1989

[Nucleolus organizer region--centromere translocation].

A karyotype 45,XX,-13,-15,+psudic (13;15)(p12.9;11.200) was observed in a young woman after two spontaneous miscarriages. After R-, C-, and NOR - banding - the rearranged element was shown to include: the long arm, the active centromere, and the NOR of chromosome 13, followed by the inactivated centromere, and the long arm of chromosome 15.

Abortion, Spontaneous↗
PubMed1988

Eleven new cases of del(9p) and features from 80 cases.

We report 11 cases of del(9p) and review 69 previously published ones. Of the 80 cases, 39 have a del(9p) as the sole anomaly. The symptoms are typical and diagnosis should be suspected at birth. The sex ratio does not appear to be unbalanced. A cardiac murmur is often present but surgery is rarely necessary. Mean IQ is 48. The number of reported cases with an associated trisomy has previously been underestimated. Death in infancy, owing mainly to gross visceral malformations, occurs more often in cases of del(9p) with another unbalanced chromosome segment (16/41) than in cases of del(9p) as the sole anomaly (1/39).

Abnormalities, Multiple↗
PubMed1988

[Molecular analysis of the parental origin of trisomy in two families with two children having regular trisomy 21].

In order to investigate the parental origin of the trisomy in two families with two free trisomy 21 affected siblings, cytogenetic and molecular analyses were performed. In each case the parental origin was the same for both patients. In one of the families an association between the concordance of the paternal origin of the trisomy and the existence of mosaicism in the blood was established. The various etiologies which may account for recurrence are discussed.

Adolescent↗
PubMed1988

[Thyroid function and trisomy 21. TSH increase and rT3 deficiency].

An excess of thyrotropin (TSH) with normal levels of tetraiodothyronine (T4) and of 3,5,3'-triiodothyronine (T3) was confirmed in the serum of 78 trisomy 21 children. A severe deficiency of 3,3',5'-triiodo-thyronine (rT3 or reverse T3) was observed and the decrease of the rT3/TSH ratio was highly significant. These new facts suggest that the rT3 deficiency plays a peculiar role in trisomy 21 (maybe through the regulation of one or few steps of monocarbons' metabolism). A systematic control of thyroid function (including the patient's rT3 level) is mandatory for the follow-up of every trisomy 21 patient.

Adolescent↗
PubMed1987

Contribution of magnetic resonance imaging to the knowledge of CNS malformations related to chromosomal aberrations.

Twelve patients presenting with various clinico-pathological syndromes related to chromosomal diseases have been evaluated using magnetic resonance imaging. They include patients with trisomy 21, trisomy 18, trisomy 13, 4p-syndrome, 5p-syndrome, and 7p-syndrome. In all these patients karyotype studies were performed demonstrating the chromosomal aberrations. All patients were examined using magnetic resonance imaging to evaluate the head and neck malformations which may be specifically associated with their chromosomal anomaly. We were particularly interested in brain abnormalities and the morphological findings correlated with some pathologic anatomical findings. A review of the literature on neuropathological data is reported and compared with the in vivo anatomical results obtained using this highly anatomical non-ionising and non-invasive investigative procedure. Particular interest is paid to trisomy 21 in which all recognizable stereotyped morphological skull and brain malformations are depicted with magnetic resonance and some other malformations demonstrated such as the excessive forward bending and ascension of the brainstem which correlated well with a simian cephalic organization.

Adolescent↗
PubMed1987

Cerebellar hemispheric agenesis.

A case report is reported of bilateral cerebellar hemispheric agenesis which was associated with secondary degeneration of cerebellofugal and cerebellopetal tracts. Somatotopic correlations between the cerebellar and the medullary olive lesions were obvious: preserved dorsal accessory olives pattern correlated with the spared vermis and normal medial accessory olives with the spared flocculi. Cerebellopetal degeneration was more difficult to analyse. The relation of cerebellar agenesis with basal ganglia abnormalities and microcephaly is discussed.

Brain↗
PubMed1987

[Phospholipid methylation in fibroblasts of patients with trisomy 21].

Comparative studies of phospholipid methylation in normal and Down syndrome (trisomy 21) fibroblasts were performed on a series of 7 pairs. Two patients showed an increased phospholipid methylation pathway as compared to the appropriate controls; one patient showed a decreased pathway; and in four patients there was no significant difference. The phospholipid methylation pathway appears to be a minor pathway, as compared to the choline pathway of phosphatidylcholine synthesis and thus does not allow the detection of an eventual disturbance of monocarbon metabolism in Down syndrome.

Cells, Cultured↗
PubMed1986

[Metabolism of monocarbons and trisomy 21: sensitivity to methotrexate].

A diminution of the mitotic index, proportionnal to the square of the dose of methotrexate, was observed in lymphocyte cultures. Six trisomy 21 patients were twice as sensitive as six controls. This highly significant result confirms the hypothesis of a disturbance of monocarbons' metabolism in trisomy 21.

Cells, Cultured↗
PubMed1986

[Cooperation between two antiparallel peptide chains covering the major groove of DNA. Molecular model of a poly-lysine/poly-AT complex].

Two antiparallel polypeptide chains oriented 5' to 3' can be adapted upon the central pillar of the major groove of a poly-A, poly-T/DNA. Lysine residues with their epsilon-NH2 fixed on the phosphates can cover the major groove entirely. This model is in accordance with all known properties of poly-lysine/poly-AT complexes. A generalization of this antiparallel disposition would be a U-turn of a single peptide chain, producing a "finger" that can recognize the base-sequence of the major groove.

DNA↗
PubMed1985

[Analysis by reflection. A new method of observing human chromosomes].

When metaphase preparations of human cells are stained with Giemsa and submitted to epi-illumination with white light a brilliant yellow-green reflexion from the chromosomes is produced, quite comparable to fluorescence after acridine orange staining. Beside a remarkable stability of the image during repeated observations, this method yields excellent resolution.

Chromosomes, Human↗
PubMed1985

[Reciprocal syndromes caused by deficiency duplication resulting from maternal t(10;18)(p12;q22) translocation].

The detection of a familial translocation, t(10;18)(p12;q22), has made possible the observation in type and countertype of two related persons with opposite chromosomal imbalance: trisomy 18q22----18qter with monosomy 10p12----10pter in one of the two and monosomy 18q22----10pter in the other. In each case the abnormalities attributable to monosomy overrule those attributable to monosomy overrule those attributable to the associated trisomy.

Adolescent↗
PubMed1985

[Recombination between the fragile site Xq27 and the gene for coagulation factor IX].

Using the Taq I restriction polymorphism of a factor IX probe, we analysed the segregation of this gene and that of the fragile site Xq27. The ancestor of this family was a healthy carrier male. Of twelve informative meioses, at least four recombinations were detected. The hypothesis of a particular instability of the distal part the long arm of the X chromosome is reconsidered.

Adolescent↗