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Biomedical subjects

K Madan

Publications and source records attributed to K Madan.

At least 55 records · Page 3Linked to original sources

Ring-18 and isopseudodicentric-18 in the same child: a hypothesis to account for common origin.

A child with two cell lines, one with a ring 18 and the other with an isodicentric 18 with a suppressed centromere is described. A hypothesis that could account for a common origin of the two cell lines is presented and discussed. The clinical features of this child were compatible with some of the features for each of the syndromes of 18p-, 18q-, and trisomy 18 as described in the literature.

Brain Diseases↗

Three cases of sex chromosome mosaicism with a nonfluorescent Y.

Clinical and cytogenetic findings in three patients mosaic for sex chromosomes (45,X0/46,XY; 45,X0/46,XY/46,XYq-, and 45,X0/46,XY/46,XYY), each with a nonfluorescent Y, are presented. Hypotheses for the origin and effect of these chromosome constitutions are discussed.

Adult↗

C-band polymorphism in human chromosome no. 6.

Chromosome analysis of G-banded cells from 92 individuals consecutively referred to the Cytogenetics Laboratory show that the paracentromeric band in the short arm (6p11), which stains negatively with G-banding and darkly with C-banding, shows a marked increase in size in about 9% of chromosome no. 6. The results of this study and those from a family in which two variants of chromosome no. 6 are segregating are compatible with a Mendelian pattern of inheritance.

Azure Stains↗

Orientation of major histocompatibility (MHC) genes relative to the centromere of human chromosome 6.

Linkage analysis of the data obtained from a three-generation Dutch family segregating for genetic variants of centromeric heterochromatic region in the band p11 on chromosome 6 (6ph), major histocompatibility (MHC) genes HLA-A, HLA-B and HLA-C, glyoxalase I (GLO) and phosphoglucomutase-3 (PGM3) showed that the genetic distance between the HLA gene cluster and 6ph is about 6 cM (at an estimated peak lod score of 3.466), that GLO is closer than HLA to the centromere and that PGM3 is probably not situated on the same chromosomal arm as HLA.

Centromere↗

An extra band in human 9qh+ chromosomes.

Chromosome analysis of G-banded cells from nine individuals showed that 9qh+ chromosomes have an extra band in the h region in approx. 3 to 50% of the cells.

Azure Stains↗

A reciprocal translocation, t(6p+; 14q-), in the pig.

A reciprocal translocation, identified as t(6p+; 14q-), is described in a 38,XX intersex pig. It is the fourth reciprocal translocation to be reported for this species, whereas Robertsonian translocations, of frequent occurrence in cattle and sheep, are so far unknown in domestic pig breeds.

Animals↗

Chromosome measurements on an XXp+ male.

Measurements carried out on an XX male show that there is a significant difference between the lengths of the short arm of the 2 X chromosomes of this patient and that the short arm of the longer X is also significantly different from that of the X chromosomes derived from normal individuals. The difference lies specifically in the size of the terminal band of the short arm. These results are consistent with the X-Y interchange hypothesis of Ferguson-Smith.

Humans↗

Chromosome studies in 1792 males prior to intra-cytoplasmic sperm injection: the Dutch experience.

The chance of a male with severe oligozoospermia or azoospermia achieving a pregnancy has undergone a revolutionary increase with the introduction of the intracytoplasmic sperm injection technique (ICSI). However, since ICSI circumvents part of the natural sperm selection mechanisms, the possible transmission of genetic defects to the offspring is a major concern. Cytogenetic analysis is a relatively simple technique to identify at least the carriers of a chromosomal aberration before starting the ICSI procedure. In order to assess the frequency of chromosomal aberrations in male ICSI candidates, we have performed a nationwide cytogenetic study. Of the 1792 males examined, 72 (4.0%) revealed a chromosomal aberration, and one individual even had two. Numerical sex chromosomal aberrations and Robertsonian translocations predominated, followed by reciprocal translocations, inversions and supernumerary marker chromosomes. The different implications, in case a chromosomal aberration is encountered prior to ICSI, are discussed.

Chromosome Aberrations↗