In the present study, the genotoxic effects of the low-calorie sweetener aspartame (ASP), which is a dipeptide derivative, was investigated using chromosome aberration (CA) test, sister chromatid exchange (SCE) test, micronucleus test in human lymphocytes and also Ames/Salmonella/ microsome test. ASP induced CAs at all concentrations (500, 1000 and 2000 mg/ml) and treatment periods (24 and 48 h) dosedependently, while it did not induce SCEs. On the other hand, ASP decreased the replication index (RI) only at the highest concentration for 48 h treatment period. However, ASP decreased the mitotic index (MI) at all concentrations and treatment periods dose-dependently. In addition, ASP induced micronuclei at the highest * Correspondence: Dr. Eyyüp Rencüzogulları, Biology Department, Faculty of Arts and Sciences, Ç ukurova University, 01330 Adana, Turkey; Fax: +90-3223386070; E-mail: reyyup@mail.cu. edu.tr. www.dekker.com concentrations only. This induction was also dose-dependent for 48 hours treatment period. ASP was not mutagenic for Salmonella typhimurium TA98 and TA100 strains in the absence and presence of S9 mix.

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An aberrant up-regulation of HOX transcript antisense intergenic RNA (HOTAIR), a long non-coding RNA (lncRNA), is associated with human cancers including gastric cancer (GC) and worse clinicopathological features. A naturally occurring functional single nucleotide polymorphism (SNP) rs920,778 (C→T) in the intronic enhancer of HOTAIR gene has been demonstrated to affect HOTAIR expression and cancer susceptibility. To investigate the association of the HOTAIR rs920778 polymorphism on the risk of GC susceptibility in Turkish population, a hospital-based case-control study was carried out consisting of 104 GC and 209 healthy control subjects matched on age and gender. The genotype frequency of HOTAIR rs920778 polymorphism was determined by using TaqMan Real-Time Polymerase Chain Reaction. No statistically significant differences were found in the allele or genotype distributions of the HOTAIR rs920778 polymorphism among GC and healthy control subjects (P > 0.05). Our results demonstrate that the HOTAIR rs920778 polymorphism has not been in any major role in genetic susceptibility to gastric carcinogenesis, at least in the population studied here. Independent studies are needed to validate our findings in a larger series, as well as in patients of different ethnic origins.

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The aim of this study was to investigate the in vivo genotoxic effects of carvacrol and thymol in bone marrow cells of rats. In the present study, both carvacrol (10, 30, 50, and 70 mg/kg b.w.) and thymol (40, 60, 80, and 100 mg/kg b.w.) significantly induced the structural and total chromosome abnormalities (CA) for all treatment periods (6, 12, and 24 h) when compared with control in bone marrow cells of rats intraperitonally administered. Both carvacrol and thymol showed similar effects with the positive control urethane on induction of the percentage of structural and total CA at the highest concentrations except the effects of carvacrol for 6 h treatment (70 mg/kg b.w. and 100 mg/kg b.w., respectively). In addition, carvacrol induced the numerical CA at all concentrations when compared to control and at two highest concentrations (50 and 70 mg/kg b.w.) when compared to solvent control. Thymol also induced the numerical CA especially at the highest concentration (100 mg/kg b.w.) for all treatment periods. It was shown that there was a dose-dependent effect on induction of structural, numerical and total CA for both carvacrol and thymol. Carvacrol and thymol decreased the mitotic index (MI) in all the concentrations and treatment times when compared with control. Carvacrol showed the similar effects with EC on decreasing the MI at 70 mg/kg b.w. for 6 h, at 30 and 50 mg/kg b.w. for 12 h and at all concentrations for 24 h treatment periods. Thymol also showed a similar effect with urethane (ethyl carbamate, EC) on decreasing the MI at 60, 80, and 100 mg/kg b.w. for 6 h and at all concentrations for 24 h treatment periods. Test substances decreased the MI in a dose-dependent manner.