PubMed Health⌕ Search

Biomedical subjects

R Bamezai

Publications and source records attributed to R Bamezai.

At least 55 records · Page 3Linked to original sources
PubMed1987

Three-way differentiation of sister chromatids in endoreduplicated (M3) chromosomes of Bloom syndrome B-lymphoid cell line.

The three-way differentiation of sister chromatids (3-way SCD) in M3 endoreduplicated chromosomes in a Bloom syndrome (BS) B-lymphoid cell line, suggested that in addition to exchanges between sister chromatids (intra-exchanges), non-sister chromatid exchanges (inter-exchanges) also occur, especially in BS high SCE cells. In BS diploid chromosomes such inter-exchanges probably get confused with intra-exchanges when total SCEs are accounted for. Bloom syndrome high SCE cells probably do not follow the same bromodeoxyuridine (BrdU) uptake pattern over three cell cycles as normal cells. The 3-way SCD in M3 endoreduplicated chromosomes can be explained on the basis of Schvartzman's second model (1979) as well as Miller's model (1976), depending on the pattern of uptake of BrdU over three cell cycles. An interference in the previous events of exchanges in the following cell cycle (i.e., cancellation of SCEs) in BS chromosomes was observed in some regions, though not in high numbers.

B-Lymphocytes↗
PubMed1987

Cell cycle rate and sister chromatid exchange profile in polyethylene glycol-exposed/unexposed Bloom syndrome and normal cells. A co-culture study.

A delay in cell cycle progression and a decrease in sister chromatid exchange (SCE) frequency was observed in Bloom syndrome (BS) cells when exposed to polyethylene glycol (PEG) treatment followed by co-cultivation with unexposed normal cells, whereas the SCE rate of both normal and BS cells increased when PEG-exposed normal cells were co-cultured with unexposed BS high SCE cells. This indicates the role of normal cells, probably of cell membranes (which were disturbed or disrupted by PEG treatment), in complementing the deficiency of BS cells under co-culture conditions, and suggests that BS cells may be deficient in membrane bound factor(s) present in normal cells.

Bloom Syndrome↗
PubMed1987

Cerebellar ataxia and total albinism.

In this report a family is described where cerebellar ataxia occurred along with total albinism. A possibility of syntenic condition of the two genes responsible for the traits could explain the occurrence of the two conditions. The presence of two traits singly in the sibs reflects a recombinant event and suggests that the linkage is not absolute. Chromosomal study did not show any structural or numerical anomalies except in 1/50 metaphase plates scored in the proband (with cerebellar ataxia) where in chromosome No. 14 proximal intense band (21) seemed to be shifted, inv. (14) (q13q23?). The affected sibs with ataxia and albinism or ataxia alone depicted relatively a lower sister chromatid exchange (SCE) rate than their parents and age matched controls.

Albinism↗
PubMed1986

Centromere spreading in a case of megaloblastic anemia "cured" under TC 199 culture conditions.

The present study discusses the possible reasons of appearance and disappearance of centromere spreading in chromosomes obtained from bone marrow cultures in RPMI 1640 and TC 199 media, respectively, in a case of megaloblastic anemia. This prevention or curing effect of centromeric region is suggested to have occurred due to exogenous thymidine present in TC 199 medium, probably reflecting the failure of proper DNA synthesis.

Aged↗
PubMed1986

Cell cycle progression and SCE rate of Bloom syndrome cells with/without co-cultivation in the presence/absence of normal cells.

The present study was undertaken to examine cell cycle progression and SCE rate in three types of B-lymphoid cell line, viz., normal (KS-86), high-SCE Bloom syndrome (BS (BS2-2) and dimorphic BS (BS-SYW). In order to compare the dimorphic condition (BS-SYW) with artificial dimorphism (co-cultivation of BS2-2 with KS-86) these experiments were designed to test whether the BS B-lymphoid cell line cultures would influence the cell cycle progression and SCE rates of a normal B-lymphoid cell line, and vice versa. The present study resolved the controversy reported in the literature, by finding a definite time period under co-cultivation conditions when the SCE in normal cells was increased after 8 days of co-culture, whereas SCE in the BS cells decreased immediately with co-cultivation. In the dimorphic BS cell line (BS-SYW) the SCE frequency of a high-SCE cell population was also observed to be lower than that of a non-dimorphic BS cell line (BS2-2), thus corroborating the experimental observations under co-cultivation conditions. The decrease in BS SCE and increase in normal SCE (after a particular time period) is attributed to numerous causes discussed in relation to the cell cycle progression.

B-Lymphocytes↗
PubMed1984

Genetics of site specific colon cancer: a family study.

In a kindred of 46 individuals of an Indian Sikh family with no history of consanguinity, 8 suffered from site specific colon (caecum) cancer (not associated with polyposis). The clinical features in the affected kindred were indicative of a "cancer family syndrome". The study of the family depicted an autosomal dominant transmission pattern of site specific colon cancer, with probably 100% penetrance in the affected individuals. A low percentage of mitotic index (MI) was observed in the two probands who were available for the study. No structural or numerical chromosomal aberrations were observed in either case. It is probable that the gene responsible in this family could have begun by mutation at the germ cell level in the 1st generation and remained in a heterozygous condition in the affected individuals.

Adenocarcinoma, Mucinous↗
PubMed1976

A familial tetraphocomelia syndrome involving limb deformities, cleft lip, cleft palate, and associated anomalies--a new syndrome.

This paper reports a rare malformation syndrome which is observed in two sibs (brother and sister) of a family. It consists of nearly symmetric reductive defects of the limbs, flexon contractures of various joints, cleft lip and cleft palate, multiple minor abnormalities including capillary hemangioma of the forehead, hypoplastic cartilages of ears and nose, micrognathia, intrauterine growth retardation, and possibly mental retardation. Chromosomes of both parents and propositi are normal. Genetic data suggest autosomal recessive inheritance.

Abnormalities, Multiple↗
PubMedDate not supplied

A study of phenotypic correlation with the genotypic status of HTM regions of KRTHB6 and KRTHB1 genes in monilethrix families of Indian origin.

We investigated 21 affected individuals in two unrelated monilethrix families of Indian origin and identified point mutation (g.4624G>A) in the HTM motif (exon-7) of the KRTHB6 gene in all the affected members leading to E413K change in this basic keratin. The HTM motif of KRTHB1, however, showed previously unreported two allelic variants, one with three novel variations (SNPs) in cis: g.4421insT (intronic); g.4461T>C (exonic); g.4485A>G (exonic) and second with only intronic variation (SNP) (g.4421insT). Interestingly, the two distinct phenotypes of: localized severe hair defect with beaded appearance confined to the scalp of all the affected members of Family 1 and of generalized unbeaded hair defect of moderate severity in Family 2, segregated in the two families, respectively, correlating with the two separate genotypes for the functionally critical HTM region of KRTHB1 gene in the background of E413K mutation in the KRTHB6 gene. Presence of E413K mutation in the HTM of KRTHB6 gene was not observed in the background of the allelic variant with three SNPs in KRTHB1 gene in homozygous condition in all the affected members of Family 1, affected with a localized but severe form of the disease. However, the same (E413K) mutation existed in the KRTHB6 gene in the background of the allelic variant with three SNPs in the KRTHB1 gene in homozygous condition, consistently in all the affected members of Family 2, where all its affected members showed the segregation of a milder form of the disease. Presence of both E413K mutation in the KRTHB6 and the variations in the KRTHB1 genes were not observed together in randomly selected 150 unaffected controls outside the two affected families. This is also the first report of HTM mutation of KRTHB6 gene in monilethrix cases of Indian origin and the first report of SNPs in the KRTHB1 gene in literature to our knowledge.

Base Sequence↗
PubMedDate not supplied

A novel promoter polymorphism (-71C>T) in KRTHB6 gene in Indian population.

We have screened the basal promoter region, of KRTHB6 gene involving CAAT and TATA boxes in randomly selected 125 individuals of Indian origin by PCR-SSCP and DNA sequencing. We observed a novel promoter polymorphism (-71C>T) which could be differentiated by using LweI restriction enzyme. The frequency of -71 C allele, allele A (Accession no AY203963), was observed to be higher ( 0.712) in comparison to -71 T allele, allele B (0.288) (Accession no. AY037552).

Base Sequence↗
PubMedDate not supplied

Inhibitory potential of Chlorella vulgaris (E-25) on mouse skin papillomagenesis and xenobiotic detoxication system.

The present study assesses the modulatory potential of Chlorella vulgaris (E-25) on murine skin papillomagenesis, and the role of xenobiotic detoxication system in modulating the papillomagenesis pattern. Topical application of E-25 (500 mg/kg b.w./day) during peri-, post- or peri- and post-initiational stages of 7,12-dimethylbenz [a] anthracene (DMBA)-induced papillomagenesis, significantly modulated the a) tumor burden to 5.00, 4.33 and 3.94 (positive control value: 5.88 b) cumulative number of papillomas to 90, 78 and 67 (positive control value: 106); and c) percent incidence of mice bearing papillomas to 94, 90 and 89 respectively (positive control value: 100). E-25 treatment alone or during peri-, post- or peri- and post-initiational stages significantly elevated the sulfhydryl (-SH) and glutathlone S-transferase (GST) levels in the liver and skin tissues. However, the levels of microsomal cytochrome b5 (Cyt. b5) and cytochrome P-450 (Cyt. P-450) were not appreciably modulated by the topical treatment of E-25. The results suggest the chemopreventive potential of E-25 during peri-, post- or peri- and post-initiational stages of murine skin papillomagenesis. The possible significance of xenobiotic detoxication system in modulating the papillomagenesis pattern is discussed.

9,10-Dimethyl-1,2-benzanthracene↗