Beyazit Cirakoglu

Association and linkage of DRD4 and DRD5 with attention deficit hyperactivity disorder (ADHD) in a sample of Turkish children

The search for genetic factors predisposing to Attention Deficit Hyperactivity Disorder (ADHD) has focused on genes that regulate dopaminergic pathways such as dopamine receptors and enzymes that regulate levels of dopamine in the synapse. There have been several reports of association between ADHD and polymorphic variants within or near DRD4, DRD5, DAT1, DBH and COMT. In this study we set out to investigate specific alleles of DRD4 and DRD5, previously reported to be associated with ADHD, in a sample of Turkish children with DSM-IV ADHD children, as well as their relation to methylphenidate response and dimensional measures of symptom domains. One hundred and four independent trios and seven dyads were analysed using the transmission disequilibrium test (TDT). We found increased transmission of the DRD4 7-repeat allele (DRD4*7) (TDT χ2u2009=u20092.79, Pu2009=u20090.047). Given that we were testing specific a priori hypotheses regarding the associated alleles, we have used one-tailed P-values throughout. There was evidence of an interaction with methlyphenidate (MPH) response and analysis of the sample excluding non-responders revealed more significant evidence for the association (TDT χ2u2009=u20094.48, Pu2009=u20090.017). We also detected a trend for linkage and association in the DRD5 polymorphism (TDT χ2u2009=u20092.38, Pu2009=u20090.06). Similar findings were obtained in relation to MPH response as analysis of MPH responders alone gave rise to a more significant association than that of the group as a whole (TDT χ2u2009=u20094.9, Pu2009=u20090.013). t-Test and logistic regression TDT analyses of DRD4*7 transmission with respect to dimensional rating scales of hyperactivity and impulsivity showed an inverse relation suggesting that in this sample DRD4*7 is associated with a lower level of ADHD symptomatology. While this may be due to stratification along a dimension of severity such that severe cases belong to a more extreme group with other specific genetic and environmental causes, similar to the model for low cognitive ability, it is more likely the result of a chance selection bias in this sample.

No association between low- and high-activity catecholamine-methyl-transferase (COMT) and attention deficit hyperactivity disorder (ADHD) in a sample of Turkish children.

Biochemical and genetic studies of attention deficit hyperactivity disorder (ADHD) suggest that regulation of catecholamine neurotransmission is a key factor in the aetiology of the disorder. In particular, it is postulated that an underactive dopamine system is associated with the disorder. In this study we have tested this hypothesis by screening a clinical sample of Turkish children with the combined subtype of ADHD with a functional variant of catecholamine-methyl-transferase (COMT) that codes for high- and low-activity variants of the enzyme. Using within-family tests of association and linkage in a sample of 72 children, we found no evidence for a genetic association or linkage. We conclude that altered regulation of catecholamines due to this polymorphism does not have a significant main effect on the risk for ADHD in this population. However, it remains feasible that more minor effects or interacting effects with other genes or environment exist.

Apolipoprotein E Genotyping in Turkish Myocardial Infarction Survivors and Healthy Controls.

The apolipoprotein (Apo) E gene is known to be polymorphic. Three common alleles determine six phenotypes which can easily be detected by restriction fragment length polymorphism. We performed apo E genotyping in myocardial infarction survivors and healthy controls for the first time in the Turkish population. DNA was amplified by polymerase chain reaction (PCR) and the PCR product was digested with restriction enzymes HhaI to detect apo E2, E3, E4 and with TaqI to detect apo E1. Relative allele frequency for the patient group was found to be 0.91 for E3, 0.07 for E2, 0.02 for E4 and for the control group 0.875 for E3, 0.067 for E2, 0.058 for E4. Copyright 1995 S. Karger AG, Basel

A New Silent Germline Mutation of the TSH Receptor: Coexpression in a Hyperthyroid Family Member with a Second Activating Somatic Mutation

BACKGROUNDnUp to date, three thyroid-stimulating hormone receptor (TSHR) germline variants have been reported for which no functional consequences have been detected by in vitro characterizations. However, familial nonautoimmune hyperthyroidism and hot nodules are clearly associated with constitutively activating TSHR germline mutations. We describe a family with a new TSHR germline mutation that is associated with euthyroidism in 13 family members and hyperthyroidism in 1 family member.nnnMETHODSnMutation analysis of the TSHR gene was performed by denaturing gradient gel electrophoresis. TSHR constructs were characterized by determination of cell surface expression, 3-5-cyclic adenosine monophosphate (cAMP) accumulation, and constitutive cAMP activity.nnnRESULTSnA novel TSHR germline mutation (N372T) was found in a man who presented with thyrotoxicosis. The mutation was also detected in 13 family members, all of whom were euthyroid. Interestingly, an additional constitutively active somatic mutation (S281N) was identified on the second parental TSHR allele of the hyperthyroid index patient. Linear regression analysis showed a lack of constitutive activity for N372T. Moreover, coexpression studies of N372T with S281N did not reveal any evidence for a functional influence of N372T on the constitutively active mutation (CAM).nnnCONCLUSIONSnN372T is unlikely to cause altered thyroid function. This is consistent with the finding that only the index patient with the additional somatic mutation S281N was hyperthyroid.

Therapeutic efficacy of Ac-DMQD-CHO, a caspase 3 inhibitor, for rat spinal cord injury

We investigated the therapeutic efficacy of Ac-DMQD-CHO, a caspase-3 inhibitor, and functional recovery in spinal cord injury in a rat model. Thirty rats were randomized into three groups of 10 each. In groups 2 and 3, spinal cord trauma was produced in the thoracic region. Group 3 rats were treated with Ac-DMQD-CHO. Treatment responses were evaluated based on histopathological and TUNEL staining findings at 24 h and 5 days post-injury. Neurologic performance was assessed during and following treatment. Twenty-four hours after injury, light microscopy examination revealed diffuse hemorrhagic necrosis, edema, vascular thrombi, and polymorphonuclear leukocyte infiltration in group 2 and 3 rats, but cavitation and demyelinization were less prominent in group 3. At this time point, treatment of the rats with Ac-DMQD-CHO significantly reduced the number of apoptotic cells. Traumatic injury to the spinal cord causes apoptosis and administration of Ac-DMQD-CHO decreases apoptosis and improves functional outcome.

Angiotensin converting enzyme gene polymorphism in Turkish asthmatic patients.

Asthma is a chronic inflammatory disease of the airways. Several candidate genes have been identified with a potential role in the pathogenesis of asthma, including the angiotensin converting enzyme (ACE) gene. We aimed to investigate the frequency of an ACE gene polymorphism in Turkish asthmatic patients and to determine its impact on clinical parameters and disease severity. Ninety-seven asthmatic patients (M/F 25/72, mean age 39 ± 13 years) and 96 healthy subjects (M/F 26/70, mean age 38 ± 12 years) were included. At baseline, all participants completed a questionnaire on demographics, symptoms, triggering factors, severity of asthma, and the presence of atopism. Blood samples were obtained from all patients and genomic DNA was isolated. The frequency of the ACE genotypes (I = insertion and D = deletion) among asthmatics and controls were compared: asthmatics showed a 40.2% prevalence of the DD genotype (n = 39), ID was 45.4% (n = 44), and II was 14.4% (n = 14.4). In the control subjects, the frequency of DD was18.8% (n = 18), ID was 50% (n = 48) and II was 31.3% (n = 30). The DD ACEgenotype was significantly more frequent in asthmatics compared with controls (p < 0.001). Asthmatics with the ID ACE genotype showed a higher frequency of drug allergies, although this was not statistically significant (p = 0.08). Asthmatics with the DD genotype appeared to have a higher incidence of asthmatic episode exacerbations due to viral infections, but again this was not statistically significant (p = 0.08). Patients with mild or moderate-severe asthma had similar frequencies of these mutations. We found a higher frequency of the ACE DD gene mutation in Turkish asthmatic patients compared with non-asthmatics, suggesting that this ACE gene polymorphism may be a risk factor for asthma but does not increase the severity of the disease.

Therapeutic efficacy of SJA6017, a calpain inhibitor, in rat spinal cord injury

Apoptosis is an important element of the secondary processes that occur after spinal cord injury. Calpain and caspases are key proteases in apoptotic cell death. We evaluated the neuroprotective effects of SJA6017 (a calpain inhibitor) and measured functional recovery in a rat spinal cord injury model. Thirty Wistar albino rats were divided into three groups of 10 animals each: sham-operated (group 1), trauma control (group 2) and trauma-plus-SJA6017 treatment (group 3). Spinal cord trauma was produced in the thoracic region of the animals. Rats in group 3 received SJA6017 1 min after trauma. Treatment efficacy was evaluated after injury using light microscopy and TUNEL staining. Neurological performance was assessed using an inclined plane and a modified version of the Tarlovs grading scale. Group 2 rats showed moderate trauma with widespread edema, hemorrhage, vascular thrombi and necrosis 24 h after injury. Group 3 rats had significantly reduced tissue injury and apoptosis. Tarlov scores revealed that group 3 rats also had ameliorated recovery of limb function. Our results demonstrate that treatment with SJA6017 reduces apoptotic cell death, preserves spinal cord tissue and improves functional outcome. Treating calpain-induced apoptosis with this agent may be a feasible therapeutic strategy for patients with spinal cord injury.

Neuroprotective effects of Ac.YVAD.cmk on experimental spinal cord injury in rats

BACKGROUNDnApoptosis as a cell death mechanism is important in numerous diseases, including traumatic SCI. We evaluated the neuroprotective effects of Ac.YVAD.cmk and functional outcomes in a rat SCI model.nnnMETHODSnThirty rats were randomized into 3 groups of 10: sham-operated, trauma only, and trauma plus Ac.YVAD.cmk treatment. Trauma was produced in the thoracic region by a weight-drop technique. Group 3 rats received Ac.YVAD.cmk (1 mg/kg, ip) 1 minute after trauma. The rats were killed at 24 hours and 5 days after injury. Efficacy was evaluated with light microscopy and TUNEL staining. Functional outcomes were assessed with the inclined plane technique and a modified version of the Tarlov grading system.nnnRESULTSnAt 24 hours postinjury, the respective mean number of apoptotic cells in groups 1, 2, and 3 were 0, 5.26 +/- 0.19, and 0.97 +/- 0.15. Microscopic examination of group 2 tissues showed widespread hemorrhage, edema, necrosis, and polymorphic nuclear leukocyte infiltration and vascular thrombi. Group 3 tissues revealed similar features, but cavitation and demyelination were less prominent than those in group 2 samples at this period. At 5 days postinjury, the respective mean inclined plane angles in groups 1, 2, and 3 were 65.5 +/- 2.09, 42.00 +/- 2.74, and 52.5 +/- 1.77. Motor grading of animals revealed a similar trend. These differences were statistically significant (P < .05).nnnCONCLUSIONSnAc.YVAD.cmk inhibited posttraumatic apoptosis in a rat SCI model. This may provide the basis for development of new therapeutic strategies for the treatment of SCI.

Effect of BCG vaccination on cytokine mRNA expression in atopic children with asthma

BACKGROUNDnTo investigate whether a preexisting T(H2)-type immune response could be suppressed by BCG immunization in atopic children with asthma.nnnMETHODS AND RESULTSnWe have used PCR to amplify reverse transcribed (RT) IFN-gamma and IL-5 mRNA expressed by peripheral blood mononuclear cells (PBMCs) in response to in vitro phytohemagglutinin A, purified protein derivative and Dermatophagoides pteronyssinus II stimulation from nine atopic children, both before and 8 weeks after BCG vaccination. We have demonstrated that IFN-gamma expression was induced in response to all stimulants (IFN-gamma/beta-actin) after the vaccination, whereas there was no expression before (P<0.001). Although there was a tendency to diminish in the expression of IL-5 mRNA in response to the stimulants, only PHA rendered a statistically significant decrease after the vaccination.nnnCONCLUSIONSnThese results provide some evidence of TH1 dominance after BCG administration in atopic children.

Enhancement of the immune response to hepatitis B virus vaccine by antigen specific IgM

In the present study, modulation of antibody response induced by Hepatitis B virus vaccine-IgM complex was investigated. Purified IgM-type anti HBv monoclonal antibody (1B11) was complexed to commercially available HBv vaccine (GenHevac B Pasteur, France) at varying concentrations of HBsAg (0.5, 1, 1.5 microg of HBsAg) and used to immunize BALB/c mice. An enhanced humoral immune response was obtained with the HBv vaccine-IgM complex at all the doses compared with those immunized by vaccine alone and increased antibody levels were observed with increased concentrations of HBsAg in vaccine formulation. Immunization with HBv vaccine-IgM complex mostly generated IgG-type antibodies in the sera of mice, and also gave rise to the development of hybrid cells which predominantly produced IgG-type monoclonal antibodies. Hence, results from this study indicate that 1B11 can be effectively used to obtain a better immune response to HBv vaccine.