Ozçaka O, Bıçakcı N, Nalbantsoy A, Köse T, Berdeli A.

Department of Periodontology, School of Dentistry, University of Ege, Izmir, Turkey.

Akin F, Turgut S, Bastemir M, Turgut G, Kursunluoglu R, Karasu U, Guclu A.

1 Department of Endocrinology and Metabolism, Faculty of Medicine, Pamukkale University , Denizli, Turkey .

Taşkıran P, Cam SF, Sekuri C, Tüzün N, Alioğlu E, Altıntaş N, Berdeli A.

Department of Medical Biology and Genetics, Medicine Faculty of Celal Bayar University, Manisa, Turkey.

OBJECTIVES: Paraoxonase (PON1) is a high-density lipoprotein (HDL)-associated esterase that hydrolyses lipoperoxides. PON1 serves as a protective factor against oxidative modification of LDL, suggesting that it may play an important role in the prevention of atherosclerotic process. Research has focused on two polymorphisms: leucine (L allele) to methionine (M allele) substitution at codon 55, and glutamine (A allele) to arginine (B allele) substitution at codon 192. STUDY DESIGN: We examined amino acid changes at codon 55 and 192 in the PON1 gene by polymerase chain reaction and using restriction enzymes in 120 patients (92 men, 28 women; mean age 48.2+/-4.3 years) with premature coronary artery disease (CAD) and in 102 healthy subjects (80 men, 22 women; mean age 46.8+/-5.2 years) with no history of CAD and a normal electrocardiogram. RESULTS: Distribution of genotypes in the patient and control groups at codon 55 were 6.7% and 4.9% for MM, 46.7% and 29.4% for LM, 46.7% and 65.7% for LL, respectively. The frequency of genotypes at codon 192 were as follows: 4.2% and 2% for RR, 40% and 35.3% for QR, and 55.8% and 62.8% for QQ, respectively. While the frequency of PON1 55M allele was higher in the CAD group (0.3 vs. 0.2), PON1 192R allele frequency did not differ (p>0.05). There was a significant relationship between the PON1 M/L55 polymorphism and CAD (p=0.017), whereas the R/Q192 polymorphism was not associated with CAD (p=0.445). CONCLUSION: These data suggest that the PON1 M/L55 polymorphism shows a significant relationship with CAD and the Q/R192 polymorphism is not a major risk factor causing susceptibility to CAD in our population.

Department of Medical Biology and Genetics, Faculty of Medicine, Gazi University, Besevler, Ankara, 06510, Turkey. akinyilmaz@gazi.edu.tr

Both beta(1)- and beta2-adrenergic receptors (beta(1)- and beta(2)-AR) have important roles in heart function mainly in response to catecholamines. Some specific polymorphisms in the beta(1)- and beta(2)-AR genes, named ADRB1 and ADRB2, respectively, have been implicated in several cardiovascular and noncardiovascular phenotypes. In this study, we aimed to investigate the possible relationship between Ser49Gly and Arg389Gly polymorphisms of the ADRB1 and Arg16Gly and Gln27Glu polymorphisms of the ADRB2 gene with ST elevation myocardial infarction (MI) in a Turkish population. One hundred patients with ST elevation MI and 100 healthy control subjects were genotyped using the PCR-RFLP method. Although the Arg389 allele of the ADRB1 gene was associated with an elevated risk of MI, the Glu27 allele of the ADRB2 gene was associated with a decreased risk of MI. Carriers of the ADRB1 Arg389 allele (heterozygotes+homozygotes) had an approximately 3.5-fold increased risk for MI than Gly389 homozygotes (OR=3.59, 95% CI=0.96-13.47, P=0.045). For the ADRB2 Gln27Glu polymorphism, subjects having one or two copies of the Glu27 allele showed a decreased risk of MI compared with Gln27 homozygote subjects (OR=0.48, 95% CI=0.24-0.94, P=0.03). Haplotype analysis of these polymorphisms showed no significant differences between groups. These results suggest that the Arg389Gly and Gln27Glu polymorphisms may be associated with an altered risk of MI in this Turkish population.

Isbilen E, Yilmaz H, Arzu Ergen H, Unlucerci Y, Isbir T, Gurdol F.

Department of Biochemistry, Faculty of Medicine, Baskent University, Ankara, Turkey.

Paraoxonase 1 (PON1) is thought to influence serum homocysteine concentrations, at least in part, due to its homocysteine thiolactonase activity and to play a role in preeclampsia and atherosclerosis. We investigated the effects of PON 55 and PON 192 polymorphisms on plasma total homocysteine (tHcy) concentrations in preeclamptic and healthy pregnants among Turkish population (N = 106). PON 55 and 192 genotypes were determined by PCR RFLP techniques. Plasma tHcy concentrations were measured by high-performance liquid chromatography. No differences were observed in the distribution of PON 1 55/192 genotypes and allele frequencies between the preeclamptic and healthy pregnants. tHcy level in the plasma of preeclamptic women was found to be increased in comparison with healthy pregnants (P < 0.01). Preeclamptic women bearing the mutated PON 192 RR and wild-type PON1 55 LL genotypes had higher tHcy levels than those of the healthy pregnants with the corresponding genotypes, supporting the possibility that the hyperhomocysteinaemia seen in preeclamptic women is associated with the PON genotypes. However, no influence of the allelic distribution on plasma tHcy concentrations was detected in either group. Our results suggest that PON1 55 and 192 genotypes might have an important role in developing hyperhomocysteinaemia and may also have a role in the pathogenesis of preeclampsia in a Turkish population.