Biomedical subjects

Lalji Singh

Publications and source records attributed to Lalji Singh.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Chromosomal abnormalities and y chromosome microdeletions in infertile men with varicocele and idiopathic infertility of South Indian origin.

Various factors cause spermatogenesis arrest in men and, in a large number of cases, the underlying reason still remains unknown. Little attention is paid to determining the genetic defects of varicocele-related infertility. The objective of our present study was to investigate the chromosomal abnormalities and Y chromosome microdeletions in infertile men of South Indian origin with varicocele and idiopathic infertility. Metaphase chromosomes of 251 infertile men with varicocele and unexplained infertility were analyzed using Giemsa-Trypsin-Giemsa (GTG) banding and fluorescence in situ hybridization (FISH). The microdeletions in 6 genes and 18 sequence-tagged-sites (STS) in the Yq region were screened using polymerase chain reaction (PCR) techniques. Out of 251 infertile men, 57 (22.7%) men were with varicocele, of which 8.77% were azoospermic, 26.31% were severely oligozoospermic, 21.05% were mildly oligozoospermic, and 43.85% were oligoasthenoteratozoospermic (OAT), and 194 (77.29%), with idiopathic infertility, of which 51% were azoospermic, 13.40% were severely oligozoospermic, 19.07% were mildly oligozoospermic, and 16.4% were with OAT. Genetic defects were observed in 38 (15.13%) infertile individuals, including 14 (24.56%) men with varicocele and 24 (12.37%) men with idiopathic infertility. The frequencies of chromosomal defects in varicocele and idiopathic infertility were 19.3% and 8.76%, respectively, whereas Y chromosome microdeletions were 5.26% and 3.60%, respectively. Overall rate of incidence of chromosomal anomalies and microdeletions in 251 infertile men were 11.5% and 3.98%, respectively, indicating a very significant higher association of genetic defects with varicocele than idiopathic male infertility. Our data also demonstrate that, among infertile men with varicocele, severely oligozoospermic and OAT men with varicocele have higher incidences of genetic defects than mildly oligozoospermic and azoospermic men.

Adult↗

PubMedDate not supplied

Male infertility: no evidence of involvement of androgen receptor gene among Indian men.

Spermatogenesis is collaboratively controlled by testosterone and follicle stimulating hormone. Testosterone and its immediate metabolite dihydrotestosterone affect their roles through the androgen receptor (AR). Mutations in the AR gene have been shown to cause partial to complete androgen insensitivity or infertility in otherwise normal males. The dependence of germ cells upon Sertoli and Leydig cells for their differentiation into sperms and deletion studies of the AR gene in animal models indicate a direct or indirect role of the AR gene in spermatogenesis. Although a few studies worldwide have reported AR mutations in male infertility, no similar study has been conducted on Indian populations. Therefore, we undertook this study to look at the contribution of AR mutations in male infertility among Indian men. We have sequenced the complete coding region of the AR gene in a total of 399 infertile samples, comprising 277 azoospermic, 100 oligozoospermic, and 22 oligoteratozoospermic samples. A total of 100 healthy males with proven fertility and the same ethnicity as the experimental group served as controls. Sequence analysis revealed no mutation in any of these samples. Our study suggests that mutations in the AR gene are less likely to cause azoospermia and oligozoospermia; however, it was difficult to rule out its effect in oligoteratozoospermia, as the sample size was small.

Adult↗

PubMedDate not supplied

CAG repeat expansion in the androgen receptor gene is not associated with male infertility in Indian populations.

CAG repeat expansion in exon 1 of the androgen receptor (AR) gene has been reported to be associated with male infertility in some but not all populations. Until now, studies have not been carried out to examine this among Indian populations. For the first time, we have analyzed the CAG repeat motif in the AR gene in 280 men with azoospermia and in 201 men with normal fertility. The mean number of CAG repeats in the AR gene of men with azoospermia was 21.7 +/- 0.18, with a high incidence of repeat number 22. Among fertile-control men, the mean number of CAG repeats was 22.4 +/- 0.19, with a predominance of repeat number 23. The highest number of CAG repeats (32) was found with low frequency in both fertile and azoospermic groups. Comparison of fertile men and those with azoospermia on the basis of CAG repeats revealed that the number of CAG repeats in both groups were similar, as revealed with a paired t test (t = 0.04; P =.967). Expansion of the CAG repeat in the AR gene is therefore not associated with male infertility in Indian populations. This suggests that what is true for one population may not be true for other populations.

Adenine↗