PubMed Health⌕ Search

Biomedical subjects

L Ekblom

Publications and source records attributed to L Ekblom.

9 recordsLinked to original sources
PubMed1985

NOR activity and centromere suppression related in a de novo fusion tdic(9;13)(p22;p13) chromosome in a child with del(9p) syndrome.

A female infant with del(9p) syndrome was found to have the karyotype 45,XX,tdic(9;13)(p22;p13) de novo. In the translocation chromosome, various combinations of AgNOR activity and inactivity were found with suppression of either the 9 or neither centromere. These phenomena of discontinuous centromeric suppression and variation in NOR activity in the one chromosome were scored on AgNOR, GTG, and a combination of AgNOR- and GTG-banded preparations. With AgNOR staining, 15.8% tdic chromosomes were AgNOR-positive, and this coincided (in preparations with GTG banding only) with 16% tdic chromosomes with a nonstaining gap present at the NOR site. This suggested that when the NOR-nonstaining gap was present the AgNOR staining would be positive; this was confirmed by the absence of gaps in combination AgNOR-GTG-banded preparations. In cells with tdic-NOR-negative chromosomes, equal proportions of cells with the 13 or both centromeres constricted were observed, but in cells with tdic-AgNOR-positive chromosomes there was only half the proportion of tdic chromosomes with both centromeres constricted; ie, there was a (significant) tendency towards inactivity of the NOR when both centromeres were constricted in the tdic chromosome. Therefore, the 2 phenomena, variation in NOR activity and centromeric suppression, are interrelated in this case.

Centromere↗
PubMed1984

Constitutive fragile sites 1p31, 3p14, 6q26, and 16q23 and their use as controls for false-negative results with the fragile(X).

Fragile(X) estimations in fragile(X)-mental retardation hemizygotes or heterozygotes can become falsely negative in stored blood (lymphocytes). This was shown in blood stored (before culture) at 4 degrees C, room temperature (25 degrees C), 37 degrees C, and 39 degrees C for 1-4 days. After storage, blood was cultured in Ham's F10-5% FC serum with 0.1 microM FUdR and scored for fra(X) and the constitutive fragile sites at 3p14 and 6q26. It was found that the proportion of cells expressing the fragile(X) and the 3p14 site varied inversely with the temperature and time of storage. In addition, 50 patients and controls were scored for the three latter sites after routine 72-96-hr culture in F10-0.05 or 0.1 microM FUdR. The 3p14 site was detected in every individual tested in a mean +/- S.D. of 11.3 +/- 3.2% of cells (0.1 microM FUdR). It was found that this site was FUdR dose dependent whereas the 6q26 site was not. The 3p14 (but not the 6q26) site is therefore suitable as a control site for the FUdR effect. It is proposed that repeat studies are necessary when less then 4% 3p14 sites are present in specimens from males referred for fra(X) estimation. Other constitutive fragile sites (eg, 1p31 and 16q23) can also be used.

Chromosome Fragile Sites↗
PubMed1981

The usefulness of NOR and RFA banding in prenatal diagnosis: a case report.

Prenatal chromosome analysis of amniotic cells showed a male fetus to carry an unusual marker D chromosome containing extra genetic material on the short arm, which could be interpreted as a possible t(D;G) or t(D;Fq) unbalanced translocation using non-branded preparations or a routine GTG band method. Analysis of this marker by NOR and RFA banding and parental chromosome studies showed the marker to be an unusual variant of the satellited area of chromosome 15, with no associated phenotypic anomalies. The usefulness of NOR and RFA banding as aids in chromosome identification in prenatal diagnosis is discussed.

Acridine Orange↗