Asli Tetik

Methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms and therapy-related toxicity in children treated for acute lymphoblastic leukemia and non-Hodgkin lymphoma

This study aimed to investigate the association of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms with serum drug levels and toxicities after high-dose methotrexate (MTX) infusion. The study included 37 children with acute lymphoblastic leukemia or non-Hodgkin lymphoma. Serum MTX levels and toxicities of bone marrow, liver and kidney were analysed. Genotype analysis of the C677T and A1298C gene polymorphisms from genomic DNA of the subjects was performed by real-time PCR. Subjects with MTHFR polymorphism for C677T (CT, TT) had significantly higher MTX levels at 24 h (p = 0.009), and these genotypes did not seem to cause toxicity. Subjects with MTHFR polymorphism for A1298C (AC, CC) had significantly higher MTX levels at 48 h (p = 0.02), and had more grade III/IV anemia (p = 0.02), thrombocytopenia (p = 0.0001), elevated AST levels (p = 0.04) and frequent febrile neutropenic episodes (p = 0.004). The present study suggests that A1298C gene, but not C677T polymorphism is associated with MTX-related toxicity.

Association of the angiotensinogen M235T and angiotensin-converting enzyme insertion/deletion gene polymorphisms in Turkish type 2 diabetic patients with and without nephropathy

OBJECTIVE Recent studies have suggested an association between a deletion variant of the angiotensin-converting enzyme (ACE) gene and diabetic nephropathy. However, this finding has not been confirmed by all investigators. Furthermore, an M235T variant of the angiotensinogen (AGT) gene has been associated with hypertension, an important risk factor for the development and progression of diabetic nephropathy. RESEARCH DESIGN AND METHODS We investigated the relationship of the ACE insertion/deletion (I/D) and AGT M235T gene polymorphisms in Turkish patients with type 2 diabetes mellitus (DM) with and without diabetic nephropathy. A total of 102 individuals were screened for the presence of the ACE I/D and AGT M235T polymorphism: 46 individuals who had type 2 DM with diabetic nephropathy and, as controls, 56 individuals who had type 2 DM without diabetic nephropathy. Gene polymorphisms were determined by the specific melting temperature (T(m)) values of the resulting amplicons after real-time online polymerase chain reaction and melting curve analysis. RESULTS The frequencies of the ACE DD, ID, and II genotypes were 34.8%, 37.0%, and 28.3%, respectively, among type 2 diabetic patients with nephropathy, and 33.9%, 42.9%, 23.2%, respectively (P=.788), in the control subjects without diabetic nephropathy. On the other hand, the frequencies of the AGT MM, MT, and TT genotypes among the same groups were 26.1%, 52.2%, 21.7% and 26.8%, 57.1%, 16.1%, respectively (P=.758). CONCLUSIONS There were no differences in the frequencies of the AGT M235T and ACE I/D genotypes between Turkish patients with type 2 DM with and without nephropathy.

Cisplatin resistance induced by decreased apoptotic activity in non-small-cell lung cancer cell lines

We have investigated defective steps in apoptosis that might account for the development of resistance. For this purpose, A549 and Calu1 NSCLC (non‐small‐cell lung cancer) cell lines were treated with cisplatin to obtain resistant sub‐lines. Gene expression profiles and the phosphorylation status of the BAD (Bcl‐2/Bcl‐XL‐antagonist, causing cell death) protein were determined for each cell line. Cell death and cytochrome c release were analysed after treating cell lines with their appropriate cisplatin doses. Gene expression of BAD, Bid, caspases 4 and 6 were clearly decreased in the resistant cell lines, and the differential phosphorylation status of BAD also seemed to play a role in the development of cisplatin resistance. Since this is a new cisplatin‐resistant Calu1 cell line, it is noteworthy that DNA fragmentation, apoptotic cell ratio and cytochrome c levels were most decreased in the CR‐Calu1 cell line.

The relationship of the methylenetetrahydrofolate reductase C677T gene polymorphism in Turkish type 2 diabetic patients with and without nephropathy

Poor glycaemic control, hypertension and duration of diabetes are risk factors for the development of diabetic nephropathy, but there may be genetic factors. Recently, a common C to T mutation at nucleotide position 677 of the MTHFR gene (MTHFR677C > T) has been reported to be correlated with hyperhomocysteinemia and the severity of coronary artery disease as macroangiopathy. We aim to investigate Turkish type 2 diabetic patients with/without diabetic nephropathy and healthy group and examine the contribution of the MTHFR gene polymorphism to the development of diabetic nephropathy.

Effect Of G2706A and G1051A polymorphisms of the ABCA1 gene on the lipid, oxidative stress and homocystein levels in Turkish patients with polycystıc ovary syndrome

BackgroundObesity, insulin resistance and hyperandrogenism, crucial parameters of Polycystic ovary syndrome (PCOS) play significant pathophysiological roles in lipidemic aberrations associated within the syndrome. Parts of the metabolic syndrome (low HDL and insulin resistance) appeared to facilitate the association between PCOS and coronary artery disease, independently of obesity. ABCA1 gene polymorphism may be altered this components in PCOS patients.In this study, we studied 98 PCOS patients and 93 healthy controls. All subjects underwent venous blood drawing for complete hormonal assays, lipid profile, glucose, insulin, malondialdehyde, nitric oxide, disulfide levels and ABCA genetic study.ResultsIn PCOS group fasting glucose, DHEAS, 17-OHP, free testosterone, total-cholesterol, triglyceride, LDL-cholesterol and fibrinogen were significantly different compare to controls. The genotype ABCA G2706A distribution differed between the control group (GG 60.7%, GA 32.1%, AA 7.1%) and the PCOS patients (GG 8.7%, GA 8.7%, AA 76.8%). The frequency of the A allele (ABCAG2706A) was higher in PCOS patients than control group with 13,0% and 23,2%, respectively. In this study, the homocystein and insulin levels were significantly higher in PCOS patients with ABCA G1051A mutant genotype than those with heterozygote and wild genotypes.ConclusionsWe found higher percentage of AA genotype and A allele of ABCA G2706A in PCOS patients compare to controls. The fasting insulin and homocystein levels were significantly higher in PCOS patients with ABCA G1051A mutant genotype than those with heterozygote and wild genotypes.

Apolipoprotein E gene polymorphism and polycystic ovary syndrome patients in Western Anatolia, Turkey

PurposeDyslipidemia, cardiovascular disease and hypertension are more frequently seen in patients with PCOS than in normal patients. We aimed at evaluating the distribution of Apo E alleles that can influence cardiovascular risk of the PCOS patients and control subjects.MethodsIn this study, 129 young women with PCOS and 91 healthy women were included. In all subjects we performed hormonal, biochemical and Apo E genetic analysis.ResultsThe Apo E3 allele was found at a significantly higher frequency in the PCOS patient group compared with the control group. The Apo E2 allele was found at a significantly higher frequency in the control group compared with the patient group with PCOS.ConclusionsAlthough there were genotype and allele differences between control and patient groups in this study, no statistically significant change was determined in lipid and other cardiovascular risk factors in connection with allele and genotype.

β1 and β2‐Adrenergic Receptor Polymorphisms and Idiopathic Ventricular Arrhythmias

Introduction: Idiopathic ventricular arrhythmias commonly refer to ventricular tachycardia (VT) and/or frequent/monomorphic premature ventricular contractions (PVC) in patients with structurally normal heart. Activation of sympathetic tone has been shown to play an important role in the provocation and maintenance of these arrhythmias. We investigated whether common single nucleotide polymorphisms in the β1 and β2‐adrenergic receptors are associated with idiopathic ventricular arrhythmias.

Role of 14‐3‐3σ in resistance to cisplatin in non‐small cell lung cancer cells

The efficacies of chemotherapeutic agents are often limited by side effects and acquired drug resistance. We have investigated whether the differential expression pattern of 14‐3‐3σ affects cisplatin response in non‐small cell lung cancer cell lines. Two pairs of parental/cisplatin resistant cell lines (A549/CRA549 and Calu1/CR‐Calu1) and clinical lung cancer biopsy samples were analysed for 14‐3‐3σ expression. Cell viability was assessed by WST assay; and 14‐3‐3σ expression was suppressed by siRNA transfection. 14‐3‐3σ mRNA expression increased in CR‐A549 and CR‐Calu1 compared with their cisplatin‐sensitive parental A549 and Calu1 cell lines. But when 14‐3‐3σ expression was suppressed, elevated cisplatin response was seen in A549 and CR‐Calu1 cell lines. Increased 14‐3‐3σ expression might also account for reduced cisplatin response in vivo, since, 14‐3‐3σ expression in clinical biopsy samples obtained from lung cancer patients undergoing cisplatin‐based chemotherapy significantly higher in the non‐responder compared with the responder group. We therefore propose that increased 14‐3‐3σ expression is correlated with cisplatin response in non‐small cell lung cancer cells; monitoring its expression might become useful in the future in predicting poor outcome to cisplatin treatment and/or the verification of acquired cisplatin resistance in lung cancer patients.

Is there any association between the Ser326Cys polymorphism of the 8-oxoguanine glycosylase 1 (OGG1) gene and risk of colon polyp and abnormal glucose tolerance in acromegaly patients?

AIM Evidence arising from experimental studies indicates an association between increased levels of the growth hormone/insulin-like growth factor 1 and oxidative stress. The association of the Ser326Cys polymorphism in the 8-oxoguanine glycosylase (OGG1) gene with a colon carcinoma and diabetes mellitus has been examined. The aim of the study was to compare the genotypic distribution of OGG1 Ser326Cys between acromegaly patients and nonacromegalic subjects and to explore whether this polymorphism is associated with a colon polyp risk and abnormal glucose tolerance. METHODS We examined 98 acromegaly patients, and 99 healthy subjects who can be compared in terms of age and gender. All participants were evaluated by anthropometric and biochemical measurements. Also, a 75-g oral glucose test and colonoscopy was applied to the patients. Genomic DNA was isolated from peripheral blood leucocytes and the genotype was assessed by melting temperature analyses after using a real-time polymerase chain reaction protocol. RESULTS Colon polyps were detected in 13 (30.2%) of 43 patients who underwent the colonoscopy. Except for diastolic blood pressure, clinical and biochemical characteristics were similar between the patients diagnosed with and without a colon polyp. A higher proportion of acromegaly patients had the Ser326Ser genotype when compared to the control group (p=0.007). Genotypes were similar between the patients with a normal glucose tolerance and an abnormal glucose tolerance (p=0.774). The frequency of the Cys allele was significantly higher in patients with polyps than those without a polyp (38.5% vs. 18.3%) (p=0.029). CONCLUSION Our results suggest that the Cys allele may influence the colon polyp risk in acromegaly patients. Large-scale studies with acromegaly patients are required to show whether being a carrier of the Cys allele is associated with the risk of a colorectal polyp.

The relationship of the endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) gene polymorphism in Turkish type 2 diabetic patients with and without diabetic foot ulcers

OBJECTIVE This study aims to evaluate the influence of eNOS G894T and VEGF C936T gene polymorphism in diabetic foot ulcers. METHOD We studied 50 patients with diabetic foot ulcers and 57 diabetic patients without diabetic foot ulcer and a control group of 75 healthy individuals. RESULTS The genotype eNOS distribution did not differ between Type 2 Diabetic Patients group and Diabetic Foot Ulcer group (P>0.05). The frequency of the polymorphic T allele in Type 2 Diabetic Patients were significantly higher than the control group (42.3% and 24.5%, respectively)(p<0.01). The frequency of the polymorphic T allele between the Type 2 Diabetic Patients and Diabetic Foot Ulcer group was similar (p>0.05). The genotype VEGF distribution did not differ between Type 2 Diabetic Patients group and Diabetic Foot Ulcer group (P>0.05). The frequency of the polymorphic T allele between the Type 2 Diabetic Patients and Diabetic Foot Ulcer group was similar for both groups (p>0.05). CONCLUSION Polymorphism of eNOS G894T is not a risk factor for diabetic foot ulcer formation. T allele is a risk factor for diabetes, but T allele is not a risk factor for diabetic foot ulcer formation. Polymorphism of VEGF C936T and T allele are not risk factors for diabetes occurence and diabetic foot formation.