Puthiya Mundyat Gopinath

Genotoxicity evaluation of heat shock in gold fish (Carassius auratus)

Genotoxicity evaluation of heat shock was carried out in Carassius auratus. The genotoxicity end points studied were nuclear anomalies (micronucleus assay), chromosomal aberrations, DNA damage (comet assay) and cell proliferation. The heat shock temperatures used were 34 degrees C, 36 degrees C and 38 degrees C. The results demonstrated that heat shock causes the induction of micronucleus at all the three temperature studied. Heat shock also inhibited cell proliferation at 38 degrees C and caused aberrations in the metaphase chromosomes at 34 degrees C and 36 degrees C. Comet assay demonstrated single strand DNA damage at all the three temperatures. The results obtained indicate that heat shock is a genotoxicant.

MTHFR gene variants C677T, A1298C and association with Down syndrome: a case-control study from South India.

BACKGROUND: The 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and low folate levels are associated with inhibition of DNA methyltransferase and consequently DNA hypomethylation. The expanding spectrum of common conditions linked with MTHFR polymorphisms includes certain adverse birth outcome, pregnancy complications, cancers, adult cardiovascular diseases and psychiatric disorders, with several of these associations remaining still controversial. Trisomy 21 or Down syndrome (DS) is the most common genetic cause of mental retardation. It stems predominantly from the failure of chromosome 21 to segregate normally during meiosis. Despite substantial research, the molecular mechanisms underlying non-disjunction leading to trisomy 21 are poorly understood. MATERIALS AND METHODS: Two common variants C677T and A1298C of the MTHFR gene were screened in 36 parents with DS children and 60 healthy couples from Tamil Nadu and Karnataka. The MTHFR genotypes were studied by RFLP analysis of PCR-amplified products and confirmed by sequencing. RESULTS: The CT genotype was seen in three each (8.3%) of case mothers and fathers. One case father showed TT genotype. All the control individuals exhibited the wild type CC genotype. A similar frequency for the uncommon allele C of the second polymorphism was recorded in case mothers (0.35) and fathers (0.37) in comparison with the control mothers (0.39) and fathers (0.37). CONCLUSION: This first report on MTHFR C677T and A1298C polymorphisms in trisomy 21 parents from south Indian population revealed that MTHFR 677CT polymorphism was associated with a risk for Down syndrome.

Studies on Brahma Rasayana in Male Swiss Albino Mice: Chromosomal Aberrations and Sperm Abnormalities

Ayurveda, the Indian holistic healthcare system encompasses traditional medicines with a principle of creating harmony and maintaining balance within the natural rhythms of the body. Rasayana is one of the branches of Ayurveda frequently used as rejuvenant therapy to overcome many discomforts and prevent diseases. It has been reported that rasayanas have immunomodulatory, antioxidant and antitumor functions. However, the genotoxic potential of many rasayanas remains to be evaluated. The present study was undertaken to assess the role of Brahma rasayana(BR) on genotoxicity in vivo in a mouse test system. The older mice (9 months) were orally fed with rasayana for 8 weeks. The treated groups showed no signs of dose-dependent toxicity at the dosage levels tested. The body weight loss/gain and feed consumption were unaffected at tested doses. Furthermore, sperm abnormalities and chromosomal aberrations were insignificant in the treatment group when compared to controls. However, there was a marginal increase in sperm count in the BR treated animals. These findings clearly indicate that there are no observed adverse genotoxic effects elicited by BR in experimental animals such as mice.

GALNS Mutations in Indian Patients With Mucopolysaccharidosis IVA

Mucopolysaccharidosis IV A (Morquio syndrome A, MPS IVA) is a lysosomal storage disease caused by the deficiency of N‐acetylgalactosamine‐6‐sulfatase (GALNS). The mutation spectrum in this condition is yet to be determined in Indians. We aimed to analyze the mutations in the GALNS gene in Asian Indians with MPS IVA. All the exons and the adjacent intronic regions of the gene were amplified and sequenced in sixty‐eight unrelated Indian families. We identified 136 mutant alleles comprising of 40 different mutations. We report twenty‐two novel mutations that comprise of seventeen missense (p.Asn32Thr, p.Leu36Arg, p.Pro52Leu, p.Pro77Ser, p.Cys79Arg, p.His142Pro, p.Tyr191Asp, p.Asn204Thr, p.Gly188Ser, p.Phe216Ser, p.Trp230Cys, p.Ala291Ser, p.Gly317Arg, p.His329Pro, p.Arg386Ser, p.Glu450Gly, p.Cys501Ser), three splice‐site variants (c.120 + 1G > C, c.1003‐3C > G, c.1139 + 1G > A), one nonsense mutation (p.Gln414*) and one frameshift mutation (p.Pro420Leufs*440). Eighteen mutations have been reported earlier. Among these p.Ser287Leu (8.82%), p.Phe216Ser (7.35%), p.Asn32Thr (6.61%) and p.Ala291Ser (5.88%) were the most frequent mutations in Indian patients but were rare in the mutational profiles reported in other populations. These results indicate that the Indian patients may have a distinct mutation spectrum compared to those of other populations. Mutant alleles in exon 1, 7 and 8 accounted for 44.8% of the mutations, and sequencing of these exons initially may be a cost‐effective approach in Asian Indian patients. This is the largest study on molecular analysis of patients with MPS IVA reported in the literature, and the first report from India.

Brahmarasayana protects against Ethyl methanesulfonate or Methyl methanesulfonate induced chromosomal aberrations in mouse bone marrow cells

BackgroundAyurveda, the traditional Indian system of medicine has given great emphasis to the promotion of health. Rasayana is one of the eight branches of Ayurveda which refers to rejuvenant therapy. It has been reported that rasayanas have immuno-modulatory, antioxidant and antitumor functions, however, the genotoxic potential and modulation of DNA repair of many rasayanas have not been evaluated.MethodsThe present study assessed the role of Brahmarasayana (BR) on Ethyl methanesulfonate (EMS)-and Methyl methanesulfonate (MMS)-induced genotoxicity and DNA repair in in vivo mouse test system. The mice were orally fed with BR (5 g or 8 mg / day) for two months and 24 h later EMS or MMS was given intraperitoneally. The genotoxicity was analyzed by chromosomal aberrations, sperm count, and sperm abnormalities.ResultsThe results have revealed that BR did not induce significant chromosomal aberrations when compared to that of the control animals (p >0.05). On the other hand, the frequencies of chromosomal aberrations induced by EMS (240 mg / kg body weight) or MMS (125 mg / kg body weight) were significantly higher (p<0.05) to that of the control group. The treatment of BR for 60 days and single dose of EMS or MMS on day 61, resulted in significant (p <0.05) reduction in the frequency of chromosomal aberrations in comparison to EMS or MMS treatment alone, indicating a protective effect of BR. Constitutive base excision repair capacity was also increased in BR treated animals.ConclusionThe effect of BR, as it relates to antioxidant activity was not evident in liver tissue however rasayana treatment was observed to increase constitutive DNA base excision repair and reduce clastogenicity. Whilst, the molecular mechanisms of such repair need further exploration, this is the first report to demonstrate these effects and provides further evidence for the role of brahmarasayana in the possible improvement of quality of life.

Chromosomal Abnormalities in 979 Cases of Amenorrhea: A Review

Abstract Primary amenorrhea refers to absence of spontaneous menarche even after the age of 16 while in secondary amenorrhea, the condition follows a period of normal menstruation. Cytogenetic data in cases with primary (n=852) (PA) or secondary (n=127) amenorrhea (SA) investigated at the Department of Genetics, Dr. A.L. Mudaliar Post Graduate Institute of Basic Medical Sciences, University of Madras, during the 25-year period 1979 to 2004 was reviewed. Routine GTG-band analysis of metaphases from peripheral blood leucocytes revealed the incidence of chromosomal abnormalities in individuals with PA and SA to be 25.82% and 7.09% respectively. In addition to numerical abnormalities, the various structural aberrations of the X chromosome encountered were deletions, isochromosome for the long arm, translocations and ring chromosomes. Ascertainment of the karyotype aided in confirmation of the provisional diagnosis, a better phenotype-genotype correlation to understand clinical heterogeneity and in genetic counseling.

Cytogenetic Evaluation of Down Syndrome: A Review of 1020 Referral Cases

Abstract A retrospective analysis was performed on 1102 cases with a provisional diagnosis of Down syndrome referred to the Department of Genetics, Dr.ALMPGIBMS, University of Madras during the period from 1979 to 2006. Cytogenetic analyses confirmed the diagnosis in 1020 cases (92.6%). Among them, regular (free) trisomy 21 constituted 83.82 percent. Mosaicism was recorded in 10.78% and Robertsonian translocations in five percent of cases. The translocation was of de novo origin in about 50 percent of the individuals where families had been investigated. Trisomy 21 was associated with structural and numerical chromosomal anomalies in one case each. A tandem 21;21 rearrangement and a familial 13;21 Robertsonian translocation with mosaicism for Y chromosome were seen in two other cases. The mean maternal age was higher in regular trisomy 21 (25.08 years) than in translocation (22.83 years) cases. An excess of males was seen in all groups except in the translocation group where the male:female ratio was 0.93. This paper summarizes the chromosomal abnormalities and the clinical features seen in these patients.

Mitochondrial DNA Variation Analysis in Cervical Cancer

This study was undertaken to investigate the mitochondrial DNA (mtDNA) variation in non-malignant and malignant cervical tissue samples. We have identified 229 and 739 variations non-malignant and malignant tissues respectively distributed over 321 locations in the D-loop (50 in non-malignant and 166 in malignant; 216 variations), coding region (139 in non-malignant and 455 in malignant; 594 variations) tRNA and rRNA genes (39 in non-malignant and 119 in malignant; 158 variations). Besides, 77 novel and 34 various other disease associated variations were identified in non-malignant and malignant samples. A total of 236 tumor specific variations in 201 locations representing 30.1% in D-loop, 59.3% in coding regions and 10.6% in RNA genes were also identified. Our study shows that D loop (in 67 locations) is highly altered followed by ND5 (35 locations) region. Moreover, mtDNA alterations were significantly higher in malignant samples by two tailed Fishers exact test (P≤0.05) with decreased mtDNA copy numbers. Bioinformatic analysis of 59 non-synonymous changes predicted several variations as damaging leading to decreased stability of the proteins. Taken together, mtDNA is highly altered in cervical cancer and functional studies are needed to be investigated to understand the consequence of these variations in cervical carcinogenesis and their potential application as biomarkers.

Genetic variation in genes involved in folate and drug metabolism in a south indian population

BACKGROUND: Genetic variations represented as single nucleotide polymorphisms (SNPs) vary across the world population. This genetic polymorphism (such as SNPs) plays an important role in pharmacogenomics. SNPs that affects cellular metabolism, by altering the enzyme activity, have an important role in therapeutic outcome. Allele frequencies in number of clinically relevant SNPs within south Indian populations are not yet known. Hence, we genotyped randomly selected unrelated south Indian subjects from different locations of south India representing the heterogeneous ethnic background of the population. MATERIALS AND METHODS: Common variants of MTHFD1, TYMS, SHMT1, MTR, MTRR, CBS and SULT1A1 gene polymorphisms were screened from healthy unrelated south Indian volunteers. Genotypes were determined using RFLP analysis of polymerase chain reaction-amplified products and confirmed by DNA sequencing. Chi-square test was performed to test for deviation from the Hardy-Weinberg equilibrium for each locus. RESULTS: Gene allele frequency for several polymorphisms in our study differed significantly between the populations of other nations reported for several of the SNPs. These results demonstrate that the populations in different geographic regions may have widely varying genetic allele frequencies for clinically relevant SNPs. CONCLUSION: The present study reports, for the first time, the frequency distribution of MTHFD1, TYMS, SHMT1, MTR, MTRR, CBS and SULTIA1 gene polymorphisms in a south Indian population. Population-specific genetic polymorphism studies will help in practicing pharmacogenomic principles in the clinics.

Down syndrome child with 48,XXY,+21 karyotype

Cytogenetic analysis in 60 clinically suspected cases of Down syndrome and their parents was carried out using conventional Giemsa-trypsin-banding technique. Fifty-five individuals (91%) exhibited a free trisomy 21. Robertsonian translocations were seen in three cases and two cases exhibited a normal karyotype. A four-month-old child, the second-born of non-consanguineous parents, possessed an extra X chromosome in addition to trisomy 21. The probands parents and his brother showed a normal karyotype. The phenotypic characteristics of this child have been discussed in the light of the published reports on double aneuploidies of XXY and trisomy 21.