Oguz Ozturk

Increased plasma levels of interleukin-6 and interleukin-8 in β -thalassaemia major

Several immunological defects can be found in patients with beta-thalassaemia, among which the impairment of neurophil and macrophage phagocytic and killing functions and the production of some cytokines are the most important. It is known that interleukin-6 (IL-6) and interleukin-8 (IL-8) are important components of the pro-inflammatory response. The plasma levels of these cytokines may be relevant in the pathophysiology of beta-thalassaemia. To assess this hypothesis, the plasma IL-6 and IL-8 concentrations in patients with beta-thalassaemia, were investigated. Fourteen patients with thalassaemia major were studied by evaluating body iron status, iron supply for erythropoiesis, and plasma IL-6 and IL-8 levels, together with 12 age-matched healthy controls. The plasma levels of IL-6 and IL-8 were determined by enzyme-linked immunosorbent assay (ELISA). Patients with beta-thalassaemia were found to have higher IL-8 concentrations than normal controls (p < 0.001) and plasma IL-6 concentrations increased significantly in the beta-thalassaemic patients compared with control subjects (p = 0.01). Serum ferritin levels of beta-thalassaemic patients were significantly higher than those of control groups (p < 0.05). IL-8 levels correlated with ferritin levels (r = 0.694; p < 0.05) and the total number of transfusions (r = 0.64; p < 0.05). Plasma IL-6 levels in beta-thalassaemic patients did not correlate with any clinical, haematological or biochemical parameters. It was also found that plasma IL-8 levels in the patients who had blood transfusions over 100 times were significantly higher than those of under 100 times (p < 0.05), whereas there was no statistical difference for IL-6. Markedly increased plasma IL-6 and IL-8 levels were documented in patients with beta-thalassaemia. Increased production of IL-6 and IL-8 might have contributed to abnormalities in iron metabolism and it is probably due to overstimulation of macrophages. Before a clinical value can be ascribed to these changes in plasma cytokine levels in beta-thalassaemia, the follow-up samples of larger series of patients with 8-thalassaemia should be evaluated.

Different effects of PPARA, PPARG and ApoE SNPs on serum lipids in patients with coronary heart disease based on the presence of diabetes

BACKGROUND The aim of this study was to investigate the individual or combined effects of PPARA-L162V, PPARG-C161T and APOE polymorphisms on hyperlipidemia in coronary heart disease (CHD) patients. METHODS Our study included 223 patients with CHD (103 with type 2 diabetes (T2DM), 120 without diabetes) and 101 controls. All genotypes were determined by PCR-RFLP technique. RESULTS Genotypic and allelic distributions of PPARA-L162V polymorphism were similar between study and control groups (p>0.05). The serum total-cholesterol (TC) and LDL-cholesterol (LDL-C) levels were higher in PPARA-V162 allele carriers in non-diabetic CHD patients (p=0.007 and p=0.038, respectively). The increasing effect of the PPARA-V162 allele on serum TC and LDL-C levels was weakened with the presence of PPARG-161T allele in the non-diabetic CHD patients. The ApoE4-PPARA-V162 allelic combination of the ApoE/PPARA genes was found to be more frequent in diabetic CHD patients independent of serum lipids (p=0.035). CONCLUSIONS The PPARA V162 allele has an increasing effect on TC and LDL-C levels and this effect was reduced by carrying PPARG T161 allele in non-diabetic CHD patients. On the other hand, the V162 allele may be associated with an increased risk of CHD in diabetic CHD patients due to the presence of ApoE4 allele independent of serum lipids. We suggest that the PPARA L162V polymorphism may have diverse effects on serum lipids and CHD risk depends on the presence of T2DM.

Is the MDR1 C3435T Polymorphism Responsible for Oral Mucositis in Children with Acute Lymphoblastic Leukemia

BACKGROUND AND AIM Although the functional consequences of MDR-1 polymorphisms have been the subject of numerous studies, to the best to our knowledge, associations with clinical side effects of anticancer drugs have yet to be assessed. Our aim was to clarify any role of the C3435T polymorphism of the MDR1 gene in oral mucositis and its relation with elevated reactive oxygen species (ROS) levels, in children with acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS The distribution of the MDR-1 C3435T polymorphism in 47 patients with ALL was determined by RFLP and compared with that of 68 healthy controls. RESULTS There were no association in distribution of genotypes of MDR-1 C3435T polymorphism and the risk of ALL. Oral mucositis were detected in 78.7% (n=37) of the patients and significantly related to the MDR-1 CT genotype (p=0.042), as confirmed by logistic regression analysis. CONCLUSION Our preliminary data suggest that children carrying the CT genotype are more prone to develop oral mucositis, which might mean that the heterozygous genotype leads to accumulation of more reactive oxygen species. Since a limited number of patients was investigated, further studies are needed to confirm these findings.

Investigation of BRAF V600E Mutation in Papillary Thyroid Carcinoma and Tumor-Surrounding Nontumoral Tissues

The aim of this study was to investigate the association between the BRAF V600E mutation incidence and histopathologic prognostic risk factors for papillary thyroid carcinoma (PTC) on the Turkish population. The contribution of BRAF V600E mutation in both tumor and tumor-surrounding nontumoral tissues of 108 patients with PTC was assessed using mutant allele-specific amplification-polymerase chain reaction. The BRAF V600E mutation was found in 52.8% of the tumor tissues, and 7.4% of the tumor-surrounding nontumoral tissues. The BRAF V600E mutation was significantly higher in the tumor tissues of the classic variant of PTC (CVPTC) cases than the follicular variant of PTC cases (p=0.001). The presence of the BRAF V600E mutation was more frequent in women, but this gender difference was not statistically significant. BRAF V600E mutation was more frequent in patients with either one of adenomatous hyperplasia or diffuse hyperplasia in tumor-surrounding nontumoral tissues (p=0.012). There was no significant difference in the BRAF V600E mutation distribution among tumor-surrounding nontumoral tissues of the two PTC variants, but it was more frequent in the CVPTC. Recent data suggest that BRAF V600E is an important marker, especially, for CVPTC. We propose that patients who had subtotal thyroid resection might have an increased risk of recurrence at the residual thyroid tissue if they have BRAF V600E mutation in their tumor-surrounding nontumoral tissues.

Association between PTEN IVS4 polymorphism and development of colorectal cancer in a Turkish population.

Background: Phosphatase and tensin homolog (PTEN) is one of the most frequently mutated suppressor genes in human cancers. However, there are no data about the role of PTEN IVS4 polymorphism in development of colorectal cancer (CRC). The authors aimed to determine the role of PTEN IVS4 variants in the etiology of CRC. Patients and methods: A hospital-based case–control study was conducted in 203 patients with CRC (127 colon, 76 rectum) and 245 healthy controls. The frequencies of PTEN IVS4 (rs 3830675) genotypes were determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Results: The (-/-) genotype of PTEN IVS4 that absence of ATCTT insertion at downstream of exon 4 in intron 4 of PTEN gene was found to be associated with 1.55-fold increased risk of colon cancer (p < 0.005; OR: 1.55, 95% CI: 1.24 – 1.94) and 1.4-fold increased risk of rectum cancer (p < 0.005; OR: 1.4, 95% CI: 1.08 – 1.82). Subgroup analyses showed that PTEN IVS4 genotypes were not associated with any clinicopathological characteristics of patients with CRC (p > 0.05). Conclusion: The (-/-) genotype of PTEN IVS4 gene might be associated with increased risk for development of CRC in a Turkish population. Further studies will clarify the exact role of PTEN IVS4 polymorphism in the etiology of CRC.

Investigation of Polymorphic Variants of PPARD and APOE Genes in Turkish Coronary Heart Disease Patients

The aim of this study was to determine the role of polymorphic variants of apolipoprotein E (APOE) and peroxisome proliferator-activated receptor delta (PPARD) genes in the development of coronary heart disease (CHD), and the PPARD and APOE gene-gene interaction in a Turkish population. This study was carried out using a sample of 223 patients with CHD (103 with diabetes and 120 without diabetes) and 101 controls. PPARD +294T/C and APOE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism technique. The PPARD and APOE genotype distributions were the same between study groups (p>0.05). In the nondiabetic CHD patients, the PPARD +294 C allele showed higher serum low-density lipoprotein cholesterol (LDL-C) level than the common +294 TT homozygote genotype (3.83 ± 1.01 vs. 3.33 ± 1.14, p=0.015). In addition, a significant association between APOE 4 and PPARD +294 C alleles was detected based on their effects on LDL-C in the nondiabetic CHD patients (+294 C/APOE4: 4.43 ± 0.88 vs. +294 TT/nonAPOE 4: 3.48 ± 1.09, p = 0.009). This association indicated the interaction of two genes on plasma LDL-C levels ascended in the order +294 T<+294 T-APOE 4<+294 C27. In addition, the CHD patients who were +294 C allele carriers had a 2.48-fold higher risk of LVH than subjects homozygous for the T allele. An increasing effect of the PPARD +294 C allele was shown on serum LDL-C levels in nondiabetic CHD patients. In addition, the results suggested that the +294 C allele might be associated with an increased LVH risk especially in male CHD patients. Furthermore, gene-gene interaction between the PPARD +294T/C and the APOE polymorphisms was observed regarding LDL-C concentrations.

The effects of age and gender on the relationship between HMGCR promoter-911 SNP (rs33761740) and serum lipids in patients with coronary heart disease.

BACKGROUND Hydroxymethylglutaryl-Coenzyme A Reductase (HMGCR) catalyzes the rate-limiting step of cholesterol biosynthesis. This enzyme is the target of the widely available cholesterol lowering statins. In this population-based case-control study, the frequencies of -911 C>A polymorphism (rs3761740) of the HMGCR gene in patients with coronary heart disease (CHD) and healthy subjects were investigated and the correlations between the different genotypes and hypercholesterolemia with cardiovascular risk factors were analyzed. METHODS The HMGCR genotypes were determined in 365 patients with CHD and 365 controls by PCR-RFLP assay. Anthropometric measurements were measured in all participants. RESULTS There was no significant difference in the genotype frequencies of the HMGCR polymorphism between the male subjects of both patient and control groups, however, the HMGCR-CC genotype was found to be more frequent in female patients with CHD than female controls (p=0.002). The HMGCR-CC genotype showed higher total-cholesterol (TC) and LDL-cholesterol (LDL-C) levels than the CA+AA genotypes in male CHD patients (p=0.018). Due to this significant sex interaction, a multivariate analysis was conducted on the patient group. In the multivariate logistic regression analysis, the HMGCR-CC genotype was significantly associated with age<55 (OR=2.837, p=0.001) and TC ≥ 5.18 mmol/L (OR=1.970, p=0.027) in male subjects. However, this association was not observed in female patients (p>0.05). This analysis confirmed that the HMGCR-CC genotype was associated with elevated TC levels in male CHD patients with age<55 years. CONCLUSION These results suggest that age and sex modify the contribution of the HMGCR-911 polymorphism to fasting serum TC, LDL-C levels and risk of CHD.

Is there any correlation between restriction fragment length polymorphism of the L-MYC gene and metastasis of human nonsmall cell lung cancer?

A potential molecular marker associated with cancer susceptibility as well as metastasis, prognosis and adverse survival, is the L-myc gene. The studies of lung cancer patients from different populations have yielded controversial results. We studied 64 nonsmall cell lung cancer (NSCLC) patients and 37 healthy controls of Turkish origin for L-myc gene polymorphism. Our aim was to test the hypothesis that there was association between L-myc S allele in NSCLC and predisposition to the disease and TNM stage indicating tumor size, node classification and metastasis. Polymerase chain reaction restriction fragment length polymorphism and agarose gel electrophoresis were used to determine the L-myc oncogene genotypes. We found no significant difference, both in the distribution of the LL, LS and SS genotypes and in the allelic frequencies, between the patient group and the control group; that is, the frequencies of L-myc alleles were, L and S, 0.59 and 0.41, 0.60 and 0.40, respectively. Our data between the patient group and the control group; that is, the frequencies of L-myc alleles were, L and S, 0.59 and 0.41, 0.60 and 0.40, respectively. Our data concerning age, sex, size of tumors, histological type of tumors showed no significant association with L-myc genotype. However, a higher frequency of L-myc S allele in the squamous cell carcinoma compared to other histological groups was found, although this difference was not statistically significant. No association was found between the L-myc RFLP and increased risk of metastasis either to the lymph nodes or to other organs. Our results suggested that L-myc gene polymorphism was not a suitable prognostic marker of metastatic development in Turkish NSCLC patients.

Increased Gastric Cancer Risk with PTEN IVS4 Polymorphism in a Turkish Population

We aimed to investigate the association of the phosphatase and tensin homolog (PTEN) IVS4 polymorphism with a gastric cancer (GC) risk in the Turkish population. A hospital-based case-control study was conducted in 93 patients with GC, and 113 healthy controls. The PTEN IVS4 (rs no: 3830675) polymorphism was determined by using polymerase chain reaction-restriction fragment length polymorphism analysis. The PTEN IVS4 (-/-) genotype exhibited a significantly elevated risk for GC compared to controls (p<0.005; odds ratio: 1.6, 95% confidence interval: 1.19-2.14). Analyses on clinicopathological parameters showed that PTEN IVS4 genotypes were not associated with any of the variables of patients with GC (p>0.05). In conclusion, the PTEN IVS4 polymorphism might contribute to the development of GC in a Turkish population. Further studies, including comparison of the PTEN IVS4 polymorphism with plasma and tissue expressions of PTEN in larger study size groups will provide a further assessment of the PTEN IVS4 polymorphism in GC patients.

New MCAD gene mutation, not previously reported in other nations, found at A1161G in Turkish population

Medium chain acyl-CoA dehydrogenase (MCAD) catalyzes the ®rst reaction of the beta-oxidation cycle for 4-10-carbon fatty acids. MCAD de®ciency is one of the most frequent inborn metabolic disorders in populations of northwestern European origin [Tanaka et al., 1992]. It is also the most common defect in mitochondrial beta-oxidation in humans. It is an autosomal recessive disorder, which usually presents in infancy. The disease manifests itself in periods of metabolic stress to the beta-oxidation system and may be fatal. In previous reports, using a polymerase chain reaction (PCR)-based assay for 985A-to-G mutation in the medium-chain acyl-CoA dehydrogenase (MCAD) gene, the following is demonstrated: ®rst, the A985G mutation in exon 11of MCAD gene is present more than 85% of the disease alleles from patients from all over the world; second, the allele frequency of A985G in the general population from most European countries is very high (1/59 in Netherlands, 1/68 in the United Kingdom, 1/74 in Scotland, 1/84 in Caucasian Americans in North Carolina, 1/101 in Denmark, 1/140 in France, and 1/143 in Normandy) [Andresen et al., 1995], but low in the southern part of western and central Europe (1/216 in Turkey, 1/240 in the Czech Republic, and 1/333 in Italy) [Tanaka et al., 1997]; third, these results support the notion of a founder effect in northwestern Europe [Yokota et al., 1991; Gregersen et al., 1993]; and fourth, MCAD de®ciency does not play a signi®cant role in the causation of SIDS [Miller et al., 1992; Arens et al., 1993; Ryan et al., 1997]. The prevalence of the 985A-to-G mutation in the medium-chain acyl-CoA dehydrogenase (MCAD) gene among the Turkish population was studied using the PCR/Nco-I method for molecular diagnosis. A frequency study of this common mutation was also conducted on blood samples from 35 healthy newborns and their mothers. Neither heterozygotes nor homozygotes for the 985A-to-G mutation were identi®ed among newborns and their mothers. After considering previous reports, we stopped using the PCR/Nco-I method for molecular diagnosis, and we performed DNA sequencing for that region. We found four A1161G mutations and no A985G mutation in 35 newborns. Because the mutation was heterozygous and the disease was recessive, the effect of the mutation at protein level on the clinical situation could not be studied. The MCAD gene was cloned and mapped to chromosome 1p21, comprising 12 exons spanning 44 kb of DNA; 80% of hot spots are found on exon 11 for A985G transition, which results in the replacement of lysine by glutamate at codon 304. A total of 26 different mutations have been identi®ed in the MCAD gene but none of these mutations (other than A985G) was counted more often than 1% in variant alleles. However, in our preliminary study, the A1161G mutation was found in 11.4% of the Turkish population, it had not been previously reported in other nations. The results of the present study ®t with previous reports that MCAD de®ciency is a common disorder in non-Turkish Caucasians, and quite rare among Japanese [Nagao, 1996.]. Therefore, newborn mass screening for MCAD de®ciency using this method would not be practical in Turkey. However, it still seems necessary to investigate a child with fatty acid oxidation disorder for the presence of MCAD de®ciency, using both biochemical and molecular genetic methods.