Biomedical subjects

F I Sahin

Publications and source records attributed to F I Sahin.

11 recordsLinked to original sources

PubMed2000

Effects of estrogen and alendronate on sister chromatid exchange (SCE) frequencies in postmenopausal osteoporosis patients.

OBJECTIVE: To compare two types of osteoporosis treatment for genotoxicity by using sister chromatid exchange (SCE) frequencies. METHOD: Fifty-seven women, aged between 40 and 64 years, composed the population in the study. SCE values of patients under estrogen replacement therapy (ERT) or alendronate therapy were compared to controls who never used any drugs for osteoporosis. RESULT: The difference between the SCE values of women taking ERT and control women was found to be statistically significant (P<0.05). The difference between women taking alendronate and untreated controls was not statistically significant. CONCLUSION: Our results indicate that alendronate does not have genotoxic effects based on SCE frequency, while ERT increases SCE frequencies.

Adult↗

PubMed2000

PCR and RFLP analysis for identification and typing of Helicobacter pylori strains isolated from gastric biopsy specimens.

Helicobacter pylori (H. pylori) infection is the most common gastrointestinal tract infection which plays an important role in the ethiopathogenesis of peptic ulcer and gastritis. In recent years, molecular biological methods have been presented for detection of H. pylori in addition to histopathological and microbiological methods. Among these methods, polymerase chain reaction (PCR) and following restriction fragment length polymorphism analyses (RFLP) are highly sensitive methods for diagnosis and follow up of patients. In this present study our aim was to amplify H. pylori urease A and B genes by PCR and perform RFLP analysis. Gastric biopsy specimens from 17 female and 18 male patients were included in the study. Amplified PCR products were subjected to RFLP analysis and typing of the bacteria in pre and posttreatment specimens were performed. H. pylori urease A and B gene amplification was observed in 32 pretreatment samples and in 8 of 21 posttreatment specimens. As a result, PCR is a sensitive method to determine the H. pylori infection. RFLP, which is another effective method in order to demonstrate the reinfection of H. pylori.

Adolescent↗

PubMed1999

Gossypol induced apoptosis in the human promyelocytic leukemia cell line HL 60.

In human promyelocytic leukemia cell line HL60, apoptosis was induced by treatment with gossypol that is an inhibitor of protein kinase C. Gossypol acetic acid was added to HL 60 cells at 50, 100, 150 and 200 microM concentrations for six hours. Morphological features of apoptosis as well as internucleosomal DNA fragmentation were evaluated by light microscope, agarose gel electrophoresis and spectrofluorometric quantitation. Our results indicated that with the effective concentrations of gossypol (50 and 100 microM), apoptosis was induced in HL 60 cells.

Apoptosis↗

PubMed1998

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.

Bisbenzimidazole↗

PubMed1998

The in vitro effect of beta-carotene and mitomycin C on SCE frequency in Down's syndrome lymphocyte cultures.

Down's syndrome (DS) has the highest incidence among chromosomal disorders and is a predisposing factor in acute leukemia pathogenesis. DS patients are sensitive to both physical and chemical inducers at the DNA level. Studies on beta-carotene, an antioxidant, suggested the there is a relationship between high beta-carotene diet and reduced tumor incidence in humans indicating that beta-carotene is a chemopreventive agent against cancer. Sister chromatid exchange (SCE) is known as a sensitive parameter among the genotoxicity tests. In this study, we aimed to investigate the in vitro effect of beta-carotene on SCE frequencies in 7 DS patients and 7 healthy controls aged between 0-16 years. A direct leukomogenic agent Mitomycin-C (MMC) was used as a powerful SCE inducer. Addition of MMC to the cultures alone resulted in a significant enhancement of SCE frequencies in both groups when compared to the spontaneous values. In the study, beta-carotene seemed to decrease MMC induced mean SCE/cell values, but did not have an effect on unstimulated cells. As this is a limited study, it is hard to conclude that beta-carotene is a chemopreventive agent in DS patients, although our results seem to support other investigators' reports.

Adolescent↗

PubMed1997

Congenital muscular torticollis: is heredity a possible factor in a family with five torticollis patients in three generations?

Although the clinical features of congenital muscular torticollis are well known, the cause of this disorder still remains hypothetical. The role of heredity is not well established, because there have been only a few studies on it. We presented a family in which five members suffer from CMT in three generations, two of whom were operated on. According to the pattern in the pedigree, probably an autosomal dominant condition could be considered.

Adolescent↗

PubMed1996

Gene BR140, which is related to AF10 and AF17, maps to chromosome band 3p25.

The genes AF10 and AF17 have been identified as the basis of the t(10;11) and t(11;17) translocations, events that result in their fusion to the MLL/HRX gene in acute myeloid leukaemias. AF10 and AF17 bear significant homology to each other within their putative zinc finger and leucine zipper domains, although they are diverged outside these regions. The BR140 gene encodes a 140 kDa protein of unknown function that contains a putative zinc finger domain, a leucine zipper region, and, in addition, a bromo domain. The zinc finger and leucine zipper domains of BR140 have significant homology to those of AF10 and AF17, suggesting that it belongs to this newly described gene family and, therefore, could be a target for chromosome translocation. To assess the potential involvement of BR140 in chromosome translocations in leukaemia, the chromosomal location of the BR140 gene has been determined by using several independent methods. A combination of Southern analysis, polymerase chain reactions (PCR) on monochromosomal cell hybrids, and fluorescence in situ hybridisation (FISH) has been used to show that the BR140 gene maps to chromosome band 3p25.

Blotting, Southern↗

PubMedDate not supplied

Numerical chromosomal abnormalities detected by atomic force microscopy.

The numerical abnormalities of human metaphase chromosomes, fixed according to standard procedures for optical microscopy but not treated for banding, were detected by atomic force microscopy (AFM). High-resolution AFM imaging of chromosomes in trisomy 13, 21, and Klinefelter syndrome can be compared directly with the traditional optical image. The unbanded metaphase chromosomes, including the extra ones in trisomic patients showed a structural pattern very similar to G-banding. Comparison of AFM images with light microscopic data allows the identification of specific chromosomes, and images of chromosomes showing numerical and structural abnormalities can then be analysed.

Chromosome Aberrations↗

PubMedDate not supplied

The mechanism of G-banding detected by atomic force microscopy.

The morphologic changes occurring in human chromosomes during G-banding by trypsin treatment on the same metaphase were followed with the aid of an atomic force microscope (AFM). It was found that trypsin treatment alone caused a pattern of collapse in the chromosomes that was clearly dependent on the duration of trypsinization. The progressive pattern of collapse first indicated the loss of internal differentiation between chromatids, then bands, and finally all internal structures, except for edges running around the chromosomes' perimeter. When stained with Giemsa, the collapsed chromosomes partly regained their original form, and transverse ridges appeared that correspond to G-positive band regions. However, the treatment of fixed chromosomes with trypsin for 42 s diminished the chromosomal edges, and the z-dimensions could not be measured even with the subsequent application of Giemsa.

Chromosome Banding↗

PubMedDate not supplied

C-banding visualized by atomic force microscopy.

C-banding is a method used for studying chromosome rearrangements near centromeres and for investigating polymorphisms. In human chromosomes, the C-bands are located at the centromere of all the chromosomes and the distal long arm of the Y chromosome. In this study, we aimed to detect the structural changes in chromosomes during the stages of C-banding by atomic force microscopy. We observed crater-like structures in the chromosomes after 2xSSC (saline sodium citrate) treatment and measured the relative difference between the heights of chromatid and centromere of the chromosomes. Results showed that the relative difference was 3 nm in chromosomes 1, 9, 16, and Y, whereas in the other chromosomes this value was 11.6 nm. After Giemsa staining, the relative difference increased by a factor of 16 in chromosomes 1, 9, 16, and Y. The other chromosomes showed no such increase, which is in accordance with our suggestion that nonhiston proteins associated with DNA in constitutive heterochromatin can make the constitutive heterochromatin resistant to C-banding.

Azure Stains↗

PubMedDate not supplied

Detection of Helicobacter pylori in dental plaque and gastric biopsy samples of Turkish patients by PCR-RFLP.

Helicobacter pylori is regarded as an important pathogen playing a key role in the pathogenesis of peptic ulcer. Different studies about the mode of transmission of the microorganism report conflicting results about dental plaque as the source of H. pylori infection. In the present study we aimed to detect the presence of H. pylori in dental plaque of Turkish patients by polymerase chain reaction (PCR) and if any to do typing by restriction fragment length polymorphism (RFLP) analysis. Fifty dyspeptic patients, to whom upper gastrointestinal endoscopy was performed, were included in the study. Dental plaques were obtained before endoscopic examination. Both dental plaque and gastric biopsy samples were amplified with Ure A and Cag A gene primers. There were no positive dental plaque samples even in the 23 patients whose gastric biopsy specimens were positive. Our findings showed that there is not a correlation between dental presentation of the microorganism and H. pylori gastritis.

Adult↗