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Biomedical subjects

S Radha

Publications and source records attributed to S Radha.

8 recordsLinked to original sources
PubMed2006

Paratesticular malignant peripheral nerve sheath tumour: a case report.

Primary malignant peripheral nerve sheath tumours (MPNST) of intrascrotal extra testicular site are extremely rare with only few cases reported in literature. These are highly malignant tumours most often associated with neurofibromatosis. The incidence in general population is 0.001%. A 35-year-old male presented with swelling of the scrotal sac of three months duration. There were no features of neurofibromatosis. The lesion was excised and was diagnosed as MPNST. The patient developed recurrence within two months.

Adult↗
PubMed2003

Syndrome-related chromosome-specific radiation-induced break points of various inherited human metabolic disorders.

The frequency, distribution pattern and localisation of gamma radiation-induced break points on the chromosomes of patients with various inherited metabolic disorders were studied to detect: (i) whether the break point distribution following irradiation is random and proportional to the length or the DNA content of the chromosome, or non-proportionally distributed on their length and at times clustering to form hot spots on certain region of the chromosomes; and (ii) to find whether there exists a syndrome-related chromosome-specific pattern of radiation-induced break points. Lymphocyte cultures from patients of haemophilia, ichthyosis, Duchenne muscular dystrophy, retinitis pigmentosa and alpha-thalassemia, whose defective gene loci were located by DNA probe method, were subjected to 3Gy of gamma radiation at G(0). The chromosomal break point analysis was carried out on all the 23 types of chromosomes (excluding Y chromosome) using G banding and FISH painting. The exact location of the break points on G-banded chromosomes was identified using a semi-automated microscope densitometer system (Leitz MPV2). In normal individuals in all the chromosomes except the chromosome 1, a random distribution of break points proportional to their length based on their DNA content was observed. However, in all the syndromes studied a mixture of hypersensitive chromosomes with a non-random distribution pattern of chromosomal break points invariably clustering to form hot spots, and chromosomes with random distribution of break points proportional to their length were observed. The hypersensitive chromosomes and their hot spots were syndrome-specific.

Cells, Cultured↗
PubMed2000

Mutation analysis of 3 genes in patients with Leber congenital amaurosis.

OBJECTIVE: To assess the frequency of mutations in the CRX, GUCY2D, and RPE65 genes in patients with Leber congenital amaurosis (LCA). PATIENTS: One hundred seventy-six probands with a clinical diagnosis of LCA were from 9 countries, with the largest subgroup being 39 probands from India. METHODS: Samples were screened with single-strand conformation polymorphism analysis followed by DNA sequencing of 3 genes (CRX, GUCY2D, and RPE65) known to be associated with LCA. RESULTS: Of the 176 probands, 28 (15.9%) harbored possible disease-causing mutations. The relative contribution of each gene to the total number of mutations was as follows: CRX, 2.8%; GUCY2D, 6.3%; and RPE65, 6.8%. No patients who harbored mutations in these genes had associated systemic abnormalities. Molecular diagnosis allowed definitive genetic counseling in a family affected with Best disease and LCA. CONCLUSIONS: Molecular diagnosis may be of benefit to patients affected with LCA. The relative paucity of mutations found in this study suggests that more LCA-associated genes remain to be discovered. CLINICAL RELEVANCE: Molecular diagnosis can confirm and clarify the diagnosis of LCA. As genotype data accumulate, clinical phenotypes associated with specific mutations will be established. This will facilitate the counseling of patients on their visual prognosis and the likelihood of associated systemic anomalies.

Adolescent↗
PubMed1998

Sodium arsenite-induced chromosomal aberrations in the Xq arm of Chinese hamster cell lines.

Non-cytotoxic concentrations (1.5, 3 and 6 microM) of sodium arsenite (SA) were used to study its cytogenetic effects with special reference to the frequency and nature of chromosomal aberrations on the X chromosome at Xq21 and at centromeric regions in CHO9, EM-C11, V79, V-H4 and CHE cell lines using Giemsa and FISH techniques. A high frequency of chromosomal breakpoints was distributed on the X chromosome localized at the secondary constriction region of the q arm (Xq21) and to a lesser degree at the centromeric region (c band-positive region), showing a high degree of fragility of these regions. This phenomenon was observed in all cell lines except for V79, where aberrations were localized only in the Xq21 region, and CHO9, where the observed breakage frequency was lowest in comparison with other cell lines and breaks were mostly located in the centromeric region rather than at Xq21. Homozygous expression of the breakpoint at Xq21 (fragile site) and in the centromeric region was also confirmed using a female Chinese hamster embryonic (CHE) cell line, which showed a similar high frequency of breakpoints at Xq21 and in the centromeric region of both X chromosomes. Further, a detailed cytogenetic study in CHO9 and its ligase-deficient mutant EM-C11 cell line showed slightly higher sensitivity to SA in a cell survival assay. No difference was found for chromosomal aberrations in Giemsa stained preparations. For SCEs a higher spontaneous frequency was evident in EMC-11. SA significantly increased the frequency of SCEs in CHO9, but no effect was found in EM-C11. Further, we observed an increased number of abnormal cells with pulverised chromosomes, decondensed chromatin, isochromosomes and hyperploidy in CHO9 and EM-C11 cell lines at all doses of SA.

Animals↗