A. J. Therkelsen

Staining of human telomeres with primed in situ labeling (PRINS).

As described, the PRINS method is a very rapid and reliable way of staining human telomeres. To obtain the maximum frequency of stained telomeres, the primer (CCCTAA)7 should be used, although the average frequency never quite reaches 100%. The frequency is strongly dependent on the age of the individual, being significantly higher in children and newborns than in adults. A difference between the (CCCTAA)7 primer and the complementary primer is demonstrated and a possible explanation is proposed, namely, that gaps in the C-rich strand cause chain elongation termination after the addition of only one dTTP molecule.

Presumptive direct insertion within chromosome 2 in man.

Most congenital structural autosomal aberrations reported in man are two point rearrangements, mainly reciprocal translocations. Some presumptive inversions (see Parrington & Edwards, 1971 ; Wahrman et al. 1972) and a presumptive chromatid interchange (Caspersson et al. 1971a) have also been found. Lejeune & Berger (1965) have suggested that some translocations may be three-point rearrangements (insertions) and may be responsible for the fact that an identical-looking chromosome rearrangement may be found in phenotypically normal as well as phenotypically abnormal members of the same family. Morphologically identical but genetically different chromosomes may be formed by crossing-over between an inserted segment and the normally located segment. Lejeune & Berger (1965) coined the term ‘aneusomie de recombinaison’ for such an event, and their hypothesis has got support also from findings by de Grouchy et al. (1966). The published cases were all translocations. I n the present paper we report on a family in which an intrachromosomal insertion seems to be the most likely explanation of the cytogenetic and clinical findings.

Ring chromosome 20 with loss of telomeric sequences detected by multicolour PRINS

Brandt CA, Kierkegaard O, Hindkjær J, Jensen PKA, Pedersen S. Ring chromosome 20 with loss of telomeric sequences detected by multicolour PRINS.

Protection of cells in tissue culture by means of cysteamine and cystamine against the action of nitrogen mustard and X-rays

Abstract The purpose of the present study was to decide whether cyst e amine and cystamine protect cells in tissue culture against the action of nitrogen mustard and X-rays. Earles L-strain of mouse fibroblasts was used in the experiments. Both cyst e amine and cystamine afford good protection against nitrogen mustard (HN2), whereas under the same experimental conditions no definite protection of the cultures is obtained against X-irradiation with doses of 1160, 870, 580, 290 and 145 r. The results suggest that the mechanisms of the protective action of cyst e amine against X-rays and against nitrogen mustards are different. It is emphasised that radio-protection of isolated cells may be obtained under other experimental conditions and with other cell types. The protection obtained against nitrogen mustard supports the view that destruction of SH groups in the cell plays a central part in the biological effect of HN2.

Origin of triploidy in spontaneous abortuses.

Fourteen triploid spontaneous abortuses were studied cytogenetically by sequential Q and C banding and the marker chromosomes were compared with those of the parents. The abortuses comprised all triploid cases in a series of 288 consecutive abortuses of the first 16 weeks of pregnancy occurring in one hospital. In 12 of the triploids the origin of the extra haploid set was conclusively determined, revealing six cases of dispermy, five failures in the first maternal and one failure in the first paternal meiotic division.

Marker chromosomes in parents of spontaneous abortuses

SummaryIn a study of spontaneous abortuses, the karyotype of 80 parental pairs were investigated in detail for chromosomal markers using Quinacrine-stained chromosome preparations from cultures of peripheral blood. Chromosomal markers were found in 26.9% of the parents and there was no difference between the frequency among parents of chromosomally abnormal and chromosomally normal abortuses.Grouping of the markers in p+ or s+ and qh+ variants showed that there was a statistically significant difference between parents with karyotypically normal and abnormal abortuses, p+ and s+ variants being more frequent in the first and qh+ more frequent in the second group.

Experience with transabdominal fine needle biopsy from chorionic villi in the first trimester: an alternative to amniocentesis

The aims of the present study were to assess the concentrations of the BM proteins in normal human second trimester amniotic fluid, to characterize these antigens and to elucidate the effects of chromosomal aberrations and other fetal disorders on these proteins. The material consisted of 21 normal and 41 pathological pregnancies, the latter being defined by an increased a-fetoprotein concentration in amniotic fluid or chromosomal aberrations in the fetus or both of these. The radioimmunoassays for the 7-S collagen domain of human type IV collagen (Risteli et al. 1980) and the fragment P1 of human laminin (Risteli & Timpl 1981) followed established procedures. The average concentrations of laminin PI and 7-S collagen in normal amniotic fluid were in the range 10-77 pg/l (average 36 pg/l) and 7-152 pg/l (average 46 pg/l), respectively. The size of the BM proteins was estimated with gel filtration on a Sephacryl 5-300 column; both amniotic fluid antigens eluted in the void volume, indicating that they are probably the intact biosynthetic forms of these BM proteins. In pathological pregnancies, when amniotic fluid a-fetoprotein concentration was increased, high concentrations of the two BM proteins were also often found. In the whole series there was a significant correlation (p < 0.01) between the amniotic fluid contents of 7-S collagen and a-fetoprotein. However, the congenital nephrotic syndrome of the Finnish type, a possible hereditary defect of the basement membrane, formed an exception, as in this condition the elevated afetoprotein concentration was accompanied by normal levels of the BM proteins in amniotic fluid.

Localisation of the classical DNA satellites on human chromosomes as determined by primed in situ labelling (PRINS)

Abstract The chromosomal localisation and relative amounts in humans of the classical DNA satellites I, II and III have been determined by using the primed in situ labelling reaction with a variety of oligonucleotide primers. The centromeres of seven of the human chromosomes, viz. nos 6, 8, 11, 12, 18, 19 and X, are not identifiably marked by any of the primers. A possible phylogenetic explanation of this is suggested and the possible relationship of the classical satellites to the function of the centromere is discussed.

Partial deletion 11q : report of a case with a large terminal deletion 11q21-qter without loss of telomeric sequences, and review of the literature

We describe the cytogenetic findings and the dysmorphic features in a stillborn girl with a large de novo terminal deletion of the long arm of chromosome 11. The karyotype was 46,XX,del(11)(q21qter). By reviewing previous reports of deletion 11q, we found that cleft lip and palate are most frequently seen in proximal 11q deletions involving 11q21. Telomeric staining using the PRINS technique demonstrated normal telomeric sequences in the deleted chromosome 11.

Structural X-chromosome abnormality in a female with gonadal dysgenesis

SummaryA patient with gonadal dysgenesis and 46 chromosomes is described. In the inactive X chromosome there seems to be a deletion of the short arms and an insertion of heterochromatin in the long arms. The most probable mechanism, to explain this structurally abnormal X is a pericentric inversion, with breakage and union having occurred in the centromeric heterochromatin of the short arm and in band q 23 of the long arm. An amplification of the centromeric heterochromatin left in the short arm is also supposed.ZusammenfassungEine Patientin mit Gonadendysgenesie und 46 Chromosomen wird beschrieben. Im inaktiven X-Chromosom scheint eine Deletion des kurzen Armes und eine Insertion von Heterochromatin im langen Arm vorzuliegen. Dieses strukturell abnorme X-Chromosom läßt sich wahrscheinlich durch eine perizentrische Inversion erklären, wobei die Bruchstellen im zentromernahen Heterochromatin des kurzen Armes und im Band q 23 des langen Armes liegen. Gleichzeitig wird eine Vergrößerung des zentromernahen Heterochromatins, welches im kurzen Arm verblieben ist, angenommen.