May F. Sadiq

Assessment of genotoxicity of waterpipe and cigarette smoking in lymphocytes using the sister-chromatid exchange assay: a comparative study.

Tobacco smoking is a major world health problem. Recently, waterpipe smoking has become more popular in many countries. Although the genotoxicity associated with cigarette smoking has been extensively investigated, studies evaluating such toxicity in waterpipe users are still lacking. In this study, we examined the genotoxicity of waterpipe smoking in lymphocytes compared with the genotoxicity of cigarette smoking. Genotoxicity was evaluated using the sister chromatid exchanges (SCEs) assay. Fifty waterpipe smokers and 18 healthy nonsmokers participated in this study. Additionally, 18 heavy cigarette smokers (CS) were recruited for comparison. The results show that waterpipe smoking and cigarette smoking significantly increase the frequencies of SCEs (P < 0.01) compared with those of nonsmokers, indicating the genotoxic effect of tobacco smoking. In addition, frequencies of SCEs were significantly higher among waterpipe smokers compared with CS (P < 0.01), indicating that waterpipe smoking is more genotoxic than cigarette smoking. Moreover, the frequency of SCEs increased with the extent of waterpipe use. In conclusion, waterpipe smoking is genotoxic to lymphocytes and the magnitude of its genotoxicity is higher than that induced by regular cigarette smoking. Environ. Mol. Mutagen., 2011.

Assessment of DNA damage using chromosomal aberrations assay in lymphocytes of waterpipe smokers

ObjectivesThe aim of this study was to investigate the genotoxicity of waterpipe smoking in the lymphocytes of waterpipe smokers using chromosomal aberrations (CAs) assay.Materials and MethodsFifty waterpipe smokers and 18 healthy non-smokers volunteered to participate in the study. Additionally, 18 heavy cigarette smokers were recruited for comparison. Chromosomal aberrations (CAs) assay was used to evaluate DNA damage in the lymphocytes.ResultsThe results showed that similarly to cigarette smoking, waterpipe smoking significantly increased the frequencies of CAs (p < 0.01). In addition, the frequencies of CAs increased with more waterpipe use.ConclusionsWaterpipe smoking causes DNA damage to lymphocytes and the damage increases with more waterpipe use.

Mutagenicity of sodium azide and its metabolite azidoalanine in Drosophila melanogaster

The mutagenic and toxic activities of sodium azide (NaN(3) ) and its organic metabolite L-azidoalanine [N(3)-CH(2)-CH(NH)(2)-COOH] were examined in the different stages of spermatogenesis in Drosophila melanogaster. Both azide and azidoalanine were toxic to the injected males, but azidoalanine was significantly less toxic than sodium azide. Following the injection with 0.2 microl of these compounds in the hemocoel of young adult wild-type males, the minimum concentrations of these compounds with complete toxic effects (zero survival) were 40 mM sodium azide and 160 mM azidoalanine. Sex-linked recessive lethals were scored by the Muller-5 method in three successive broods, representing sperms (brood A), spermatids (brood B), and a compiled group of meiotic and premeiotic germ cell stages (brood C). The results provide strong experimental evidence that azidoalanine is significantly (p<0.01) mutagenic to all stages of spermatogenesis in Drosophila melanogaster. Sodium azide, however, was not significantly (p>0.05) mutagenic and did not increase the rate of sex-linked recessive lethals over those produced by the control group injected with 0.45% NaCl. These results indicate the requirement of metabolic activation of azide in Drosophila as a prerequisite for its mutagenic effects.

Methylenetetrahydrofolate Reductase Polymorphisms C677T and A1298C as Maternal Risk Factors for Down Syndrome in Jordan

BACKGROUND The activity of the methylenetetrahydrofolate reductase (MTHFR) enzyme is regulated by the two polymorphisms C677T and A1298C, which reduce enzyme activity and result in hypomethylation of chromosomes that increase the risk of nondisjunction. These polymorphisms are suggested to be risk factors for Down syndrome (DS) in some populations. AIM The aim of this study was to test if C677T and A1298C polymorphisms are correlated to maternal risk of DS in Jordan. METHODS The proportions of C677T and A1298C polymorphisms were examined in 53 case mothers who delivered DS children and 29 controls. The median age of case mothers was 35 years when delivering their affected children. Polymerase chain reaction-restriction fragment length polymorphism was used for genotyping. RESULTS The frequency of MTHFR C677T allele in all DS mothers was 3.2-fold higher than in the controls (odds ratio [OR] = 3.12, 95% confidence interval [CI]: 1.303-7.677). Also, the proportion of 677T in the older case mothers was different from the controls, but was significantly higher in younger case mothers than in the controls (OR = 4.2, 95% CI: 1.61-10.97, p = 0.003). The proportions of 677CT and 677TT genotypes in younger cases are, respectively, 10- and 9-fold higher than in the controls. The proportions of MTHFR A1298C are significantly different among all case groups and the controls (χ(2) = 4.27, p = 0.127), but there was a significant difference between young case mothers and both older case mothers group and the controls (OR = 1.25, 95% CI: 0.405-3.85, p = 0.698). CONCLUSIONS There is strong association between MTHFRC677T and maternal risk of DS in Jordanian mothers younger than 35 years old and the MTHFR1298C allele has a lesser but additive risk effect in MTHFR677T/1298C compound heterozygotes.

Associations of variants in MTHFR and MTRR genes with male infertility in the Jordanian population.

Folate pathway is expected to play an important role in spermatogenesis since it is involved in DNA synthesis, repair and methylation. The purpose of this study was to examine the association between male infertility and the MTHFR (C677T and A1298C) and MTRR (A66G) polymorphisms. A group of 300 males was recruited in this study from different Jordanian infertility clinics. Of these, 150 cases of infertile men that included oligozoospermia cases (n=45), severe oligozoospermia (n=71) and azoospermia (n=34) were studied. The other 150 males were age matched fertile controls. Genotyping of MTHFR and MTRR polymorphisms was performed using PCR-RFLP technique. The results showed an association between MTHFR 677TT genotype and male infertility (P<0.05). However, the distribution of MTHFR A1298C and MTRR A66G genotypes were not different between the fertile and infertile groups (P>0.05). In addition, none of the examined polymorphisms was related to any of the semen parameters in the infertile group. In conclusion, this study showed that MTHFR C677T polymorphism is associated with male infertility in Jordanians.

THE EFFECT OF TRIFLUOPERAZINE ON THE GENOTOXICITY OF BLEOMYCIN IN CULTURED HUMAN LYMPHOCYTES

The effects of trifluoperazine on the toxicity and mutagenicity of bleomycin were examined in cultured human lymphocytes. Lymphocyte cultures were initiated from three adult healthy non-smoking male volunteers. Cultures were exposed to the drugs for either three or twenty hours prior to cell collection. The toxic and clastogenic effects of the different treatments were represented by the reduction in the mitotic indices and the induction of chromosomal aberrations (CA) respectively. Both TFP and BLM significantly increased CA frequencies and reduced the mitotic indices (MI) following all treatments. The reduction in the mitotic indices and the increase in CA frequencies induced by the combined administration of both BLM and TFP were highly significant (p ≤ 0.001), but they were not significantly different from the sum of those induced by the separate treatments with the two drugs. These combined treatments, however, potentiated the odds ratios compared to those of the separate drug treatments. Therefore, though the effect of TFP on the clastogenic and cytotoxic effects of BLM was additive, the observed potentiation of the odds ratios of the combined treatments compared to those of the separate treatments suggested a significant enhancement in the expected chemotherapeutic effects of BLM when administered with TFP.

Ancient founder mutation is responsible for Imerslund-Gräsbeck Syndrome among diverse ethnicities

BackgroundImerslund-Gräsbeck syndrome (IGS) was described just over 50 years ago by Olga Imerslund and Ralph Gräsbeck and colleagues. IGS is caused by specific malabsorption of cobalamin (Cbl) due to bi-allelic mutations in either the cubilin gene (CUBN) or the human amnionless homolog (AMN). Mutations in the two genes are commonly seen in founder populations or in societies with a high degree of consanguineous marriages. One particular mutation in AMN, c.208-2A>G, causing an out-of-frame loss of exon 4 in the mRNA, is responsible for some 15% of IGS cases globally. We present evidence that this founder mutation causes a substantial percentage of cases among diverse ethnicities and that the mutation is as old as human civilization.MethodsPartial genotyping indicated a founder event but its presence in diverse peoples of Arabic, Turkish, Jewish, and Hispanic ancestry suggested that the mutation might be recurrent. We therefore studied the flanking sequence spanning 3.5 Mb to elucidate the origin of the haplotype and estimate the age of the mutation using a Bayesian inference method based on observed linkage disequilibrium.ResultsThe mutations distribution, the size of the shared haplotype, and estimates of growth rate and carrier frequency indicated that the mutation was a single prehistoric event. Dating back to the ancient Middle East around 11,600 BC, the mutation predates the advent of writing, farming, and the monotheistic religions of the region.ConclusionsThis mutation causes over 50% of the IGS cases among Arabic, Turkish, and Sephardic Jewish families, making it a primary target for genetic screening among diverse IGS cases originating from the Middle East. Thus, rare founder mutations may cause a substantial number of cases, even among diverse ethnicities not usually thought to be related.

MUTAGENIC ACTIVITY OF RHODIUM(III) COMPLEXES WITH 2,2'-BIQUINOLINE AND 2-(2'-PYRIDYL)QUINOLINE

Abstract The mutagenic activity of the rhodium(III) complexes with 2,2′-biquinoline(biq) and 2-(2′-pyridyl)quinoline(pq) namely, mer - and fac -[Rh(pq)Cl 3 (H 2 O)], cis -[Rh(NN) 2 X 2 ]X (NN = biq or pq; X = Cl, Br) and cis -[Rh(pq) 2 Cl 2 ] [Rh(CO) 2 Cl 2 ]·H 2 O, was investigated in strains of Salmonella typhimurium TA1530 (hisG46, Δgal, Δuvr, R − ) and TA98 (hisD3052, ΔuvrB, rfa, R + ). All of the complexes studied appear to be active in inducing both base substitution and frame shift mutations. The complex cis -[Rh(biq) 2 Cl 2 ]Cl exhibits the highest activity in both strains and has the lowest toxicity.

Human Diversity in Jordan: Polymorphic Alu Insertions in General Jordanian and Bedouin Groups

ABSTRACT Jordan, located in the Levant region, is an area crucial for the investigation of human migration between Africa and Eurasia. However, the genetic history of Jordanians has yet to be clarified, including the origin of the Bedouins today resident in Jordan. Here, we provide new genetic data on autosomal independent markers in two Jordanian population samples (Bedouins and the general population) to begin to examine the genetic diversity inside this country and to provide new information about the genetic position of these populations in the context of the Mediterranean and Middle East area. The markers analyzed were 18 Alu polymorphic insertions characterized by their identity by descent, known ancestral state (lack of insertion), and apparent selective neutrality. The results indicate significant genetic differences between Bedouins and general Jordanians (p = 0.038). Whereas Bedouins show a close genetic proximity to North Africans, general Jordanians appear genetically more similar to other Middle East populations. In general, these data are consistent with the hypothesis that Bedouins had an important role in the peopling of Jordan and constitute the original substrate of the current population. However, migration into Jordan in recent years likely has contributed to the diversity among current Jordanian population groups.

The Mutagenic And Toxic Effects Of Bleomycin And Trifluoperazine In Drosophila Melanogaster

The mutagenic and toxic effects of trifluoperazine and bleomycin on Drosophila were investigated in the progenies of males injected with 0.2 microliter of bleomycin and/or trifluoperazine. The Muller-5 method was used to study the induction of complete- and mosaic-sex-linked recessive lethals induced by 0.1 microgram/ml bleomycin and/or 0.1 mM trifluoperazine in the five successive broods, mainly representing the different stages of spermatogenesis. Trifluoperazine increased the induction rate of sex-linked recessive mutations above the spontaneous rates of the control, but these increases were not statistically significant at the 5% level27 in any of the five different broods. Contrary to trifluoperazine, bleomycin significantly (5% level)27 increased the induction rate of the complete sex-linked recessive lethals over those of the control in the meiotic and premeiotic broods C and D, and the meiotic brood E. As with the separate treatment with bleomycin, the frequencies of the complete sex-linked recessive lethals induced by the simultaneous combination treatment of 0.1 microgram/ml bleomycin and 0.1 mM trifluoperazine were significantly higher than those of the control at the 5%27 level, only in the meiotic and premeiotic broods, but they were not significantly higher than those induced by bleomycin treatment alone19. Treatments with 0.1 mM trifluoperazine enhanced the toxicity, sterility and the number of mutated clusters induced by 0.1 mM bleomycin but did not significantly increase the rates of induced lethals over the additive effects of both drugs in the meiotic and premeiotic stages, suggesting no potentiation effects for trifluoperazine over those of bleomycin in Drosophila. Higher concentrations of the two drugs could not be used due to their high toxicity and sterility effects.