Feride İffet Şahin

Interactions of DNA with fluorescent dyes: by scanning tunneling microscopy

Genomic DNA was obtained from peripheral blood samples of healthy volunteers and interacted with two fluorescent dyes (i.e. Hoechst 33,258 and ethidium bromide) in aqueous media. These media containing DNA-dye complexes deposited on the gold coated mica surfaces. Then, STM images were obtained in which the STM was operated in air at atmospheric pressure with a tip-to-substrate bias voltage of 250-1000 mV (sample positive) and the tunneling currents in the range of 10-20 pA by using etched tips of Pt/Ir, in constant current mode. Both dyes from molecular clusters on DNA. While, the Hoechst molecules were observed on the DNA chains at regular distances, the ethidium bromide molecular clusters did not.

Effect of Hereditary Hemochromatosis Gene H63D and C282Y Mutations on Iron Overload in Sickle Cell Disease Patients.

Objective: Hemochromatosis is an autosomal recessive disease that is one of the most important reasons for iron overload. Sickle cell disease is a hemoglobinopathy that occurs as a result of a homozygous mutation in the hemoglobin gene. Erythrocyte transfusion is frequently used in the treatment of this disease. Iron overload as a result of transfusion is important in the mortality and morbidity of sickle cell anemia patients as well as in other hemoglobinopathies. In this study, the effect of hemochromatosis gene (HFE) p.H63D and p.C282Y mutations on transfusion-related cardiac and liver iron overload in sickle cell disease patients who carry homozygous hemoglobin S mutation has been investigated. Materials and Methods: This is a prospective single-center cross-sectional study in patients with homozygous hemoglobin S mutation between the years 2008 and 2013. The patients were divided into two groups. The first group (group A, n=31) was receiving chelation therapy and the second group (group B, n=13) was not. Direct and indirect iron loads were analyzed by magnetic resonance imaging and biochemically, respectively. HFE gene mutations were analyzed by polymerase chain reaction-restriction fragment length polymorphism method. Statistical analyses were performed by independent samples t-test. Results: p.H63D mutation was detected in 10 (32.3%) patients in group A and in only 1 patient (7.7%) in group B. When the 2 groups were compared for iron overload, iron deposition in the liver was significantly higher in group B (p=0.046). In addition, in group A, iron deposition was significantly higher in HFE mutation carriers compared to patients without the mutation (p=0.05). Conclusion: Results of this study showed that HFE gene mutations are important in iron deposition in the liver in patients with sickle cell disease.

BRCA1 and BRCA2 sequence variations detected with next-generation sequencing in patients with premature ovarian insufficiency

OBJECTIVE Although the association between BRCA1 and BRCA2 gene mutations and breast and ovarian cancer is known, there is insufficient data about premature ovarian insufficiency (POI). However, several studies have reported that there might be a relationship between POI and BRCA1 and BRCA2 gene mutation. Therefore, in the present study, we aimed to investigate the role of BRCA1 and BRCA2 gene mutations in the etiology of POI in a Turkish population. MATERIAL AND METHODS The cohort was classified into two groups: a study group, consisting of 56 individuals diagnosed with premature ovarian insufficiency (and who were younger than 40 years of age, had an antral follicle count <3-5, and FSH levels >12 IU/I), and a control group, consisting of 45 fertile individuals. A total of 101 individuals were analyzed by next-generation sequencing to detect BRCA1 and BRCA2 gene mutations. RESULTS We detected four new variations (p.T1246N and p.R1835Q in BRCA1 and p.I3312V and IVS-7T>A in BRCA2) that had not been reported before. CONCLUSION We did not find an association between the BRCA1 and BRCA2 gene mutations and premature ovarian insufficiency. However, larger, functional studies are needed to clarify the association.