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Biomedical subjects

I Dinçer

Publications and source records attributed to I Dinçer.

10 recordsLinked to original sources
PubMed2001

Methylenetetrahydrofolate reductase gene polymorphism and risk of premature myocardial infarction.

BACKGROUND: Elevated plasma homocysteine level is an independent risk factor for cardiovascular disease. A common mutation (nucleotid 677C-T) in the gene coding for methylenetetrahydrofolate reductase (MTHFR) has been reported to reduce the enzymatic activity of MTHFR and is associated with elevated plasma levels of homocysteine, especially in subjects with low folate intake. HYPOTHESIS: Methylenetetrahydrofolate reductase T/T genotype may be a risk factor for premature MI in Turkish population who are known to have low folate levels. METHODS: The study group was comprised of 96 men (aged <45 years) with premature myocardial infarction (MI) and 100 age- and gender-matched controls who had no history or clinical evidence of coronary artery disease (CAD) and/or MI. DNA was extracted from peripheral blood and genotypes were determined by polymerase chain reaction, restriction mapping with HinfI, and gel electrophoresis. Conventional risk factors for CAD were prospectively documented. RESULTS: Allele and genotype frequencies among cases and control subjects were compatible with Hardy-Weinberg equilibrium. The frequencies of T/T, C/T, and C/C genotypes among patients with MI and control subjects were 15.6, 40.6, and 43.8%, and 5, 35, and 60%, respectively. Multivariate analyses identified smoking, MTHFR C/T polymorphism, diabetes mellitus, family history of CAD, and hypertension as the independent predictors of premature MI. Defining patients with non-T/T genotype (C/C and C/T combined) as reference, the relative risk of MI for subjects with T/T genotype was 5.94 (95% confidence interval: 1.96-18.02, p = 0.0016). CONCLUSIONS: Our findings suggest that C677T transition in the MTHFR gene may be a risk factor for premature MI in Turkish men.

Adult↗
PubMed2001

The relation between transmitral early filling wave deceleration time and the recovery of atrial contractility after electrical cardioversion of atrial fibrillation.

BACKGROUND: Electrical cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial dysfunction and this phenomenon may lead to thrombus formation and embolic stroke. Delay of atrial mechanical function recovery may be related to ventricular diastolic function. OBJECTIVE: This study examined the effects of left ventricular diastolic function as well as the multiple clinical factors on the recovery of atrial systolic function after cardioversion for atrial fibrillation. METHODS: A total of 44 patients (28 male, 16 female, 61+/-18 years) with chronic AF (> or =1 month) underwent electrical cardioversion. Deceleration time of early filling wave (pre-CV EDT) on transmitral inflow obtained by using Doppler echocardiography before cardioversion and serial transmitral inflow Doppler variables were recorded through a 1 week study period in all patients. Various clinical (age, gender, the duration of AF) and echocardiographic variables (pre-CV EDT, left atrial dimension, left ventricular ejection fraction) were tested for an association with peak atrial filling wave velocity (VA) on day 1, 3 and 7 after cardioversion. RESULTS: EDT measured before cardioversion had a strong linear correlation with peak VA on every echocardiographic evaluation after cardioversion (Regression coefficient (R)=0.69, P<0.001; R=0.78, P<0.001 and R=0.83, P<0.001, on day 1, day 3 and day 7, respectively). The effect of left ventricular ejection fraction on peak VA was weaker than those of EDT. The duration of AF showed an inverse association with the recovery of atrial function, but this lost on multivariate analysis. None of the other parameters significantly correlated with peak VA after cardioversion. CONCLUSION: The recovery of atrial mechanical function after cardioversion, as assessed by peak VA on transthoracic Doppler echocardiography is mainly associated with the left ventricular diastolic function as measured by EDT, whereas the left ventricular systolic function relatively a small effect on this outcome. The duration of AF does not have any association with peak VA, possibly if it is chronic.

Analysis of Variance↗
PubMed2001

Association between the severity of heart failure and the susceptibility of myocytes to apoptosis in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: Bcl-2 proto-oncogene, an inhibitor of apoptosis and Bax proto-oncogene, an inducer of apoptosis play critical roles in the molecular circuit controlling apoptosis in cardiac muscle. The ratio of Bax to Bcl-2 proto-oncogene determines survival or death after an apoptotic stimulus. We speculated that susceptibility of myocytes to apoptosis determined as the Bax/Bcl-2 ratio might vary with the severity of heart failure. METHODS AND RESULTS: We studied immunohistochemically 108 endomyocardial biopsy specimens from 30 patients with idiopathic dilated cardiomyopathy (mild heart failure, n=14; moderate or severe heart failure, n=16) with the use of Bcl-2 and Bax monoclonal antibodies. The expression of each protein was determined semiquantitatively as the fraction of myocytes labeled with specific monoclonal antibodies using a digital morphometric analysis system. Patients with mild heart failure showed significantly increased Bax/Bcl-2 ratio than the patients with advanced heart failure (1.59+/-1.26 vs. 0.34+/-0.43, P=0.002). The expression of Bcl-2 was found to be independent of the severity of heart failure whereas the expression of Bax was significantly higher in patients with mild heart failure compared to the patients with moderate or severe heart failure (52.1+/-29.3 vs. 21.6+/-22.4%, P=0.005). Additionally, Bax/Bac-2 ratio was inversely correlated with the mitral E-interventricular septum distance, left ventricular end-systolic and end-diastolic diameter. CONCLUSION: The susceptibility of myocytes to apoptosis is significantly increased in the early phase of heart failure but it decreases with worsening of the disease due to depressed expression of Bax onco-protein. Increased myocyte susceptibility to apoptosis may have a role in the transition from mild heart failure to severe in patients with idiopathic dilated cardiomyopathy.

Adult↗
PubMed2001

Hyperhomocysteinemia and restenosis.

OBJECTIVE: This study was undertaken to assess the effect of plasma homocysteine level on angiographic restenosis 6 months after coronary angioplasty. METHODS: The plasma homocysteine level was measured in 100 consecutive patients at the time of coronary angioplasty, 56 patients who attended a 6-month follow-up angiogram being enrolled to the study; the 44 patients without a control coronary angiogram were not enrolled. Patients with and without angiographic restenosis were designated as groups A (n = 34) and B (n = 22) respectively. RESULTS: The baseline demographic (groups A and B), angiographic (groups A and B) and procedural characteristics were similar in both groups. The mean plasma homocysteine level (SD) was 15.2 (7.7) and 11.1 (2.5) mumol/l in groups A and B respectively (P = 0.007; 95% CI -6.9 to -1.1). With respect to the plasma homocysteine level, the upper and the lower thirds were compared by binary logistic regression (the lower third homocysteine level being < 10.6 mumol/l and the upper third homocysteine level > 14.1 mumol/l). The angiographic restenosis rate for the lower and upper tertiles was 47.4% and 89.5% respectively (P = 0.01; OR = 9.4; 95% CI 1.6-52.7). After adjustment for age and sex, the statistical significance did not change (P = 0.013; OR = 9.43; 95% CI 1.6-54.9). Even after adjustment for age, sex, smoking, hypertension, hypercholesterolemia, and diabetes mellitus, there was a statistically significant difference between the upper and lower tertiles (P = 0.008; OR = 41.3; 95% CI 2.6-635). CONCLUSION: Increased plasma homocysteine level and diabetes mellitus were independent risk factors for angiographic restenosis after percutaneous transluminal coronary angioplasty and coronary stenting.

Angioplasty, Balloon, Coronary↗
PubMed2001

Is there any effect of chronobiological changes on coronary angioplasty?

AIMS: We hypothesized that If there is a chronobiologic variation in the development of acute ischaemic events which is mainly attributed to the tendency for thrombus formation in the morning hours, same time dependent variations must also be seen in the development of ischaemic events after percutaneous transluminal coronary angioplasty (PTCA) and PTCA with stent implantation. METHODS: Enrolled in this study were 349 consecutive patients with single vessel disease and undergoing elective single vessel angioplasty. Patients had been observed for the development of immediate postprocedural ischaemic events. Working hours of our laboratory were divided into 2-hourly intervals in order to define the ending time of procedure. Analysis of acute complications was carried out according to the ending time of procedure. RESULTS: There was no difference with regard to clinical presentation, but patients who had complications had higher blood cholesterol level (P < 0.05). Patients with stent implantation had more adverse events than the PTCA group, but this difference did not reach the statistical significance (P = 0.07). The time interval between 10:30 a.m.-12:30 p.m. was found to be an independent risk factor for the negative outcomes (P = 0.043, Relative Risk 4838). CONCLUSION: The results of our study have demonstrated that postprocedural complications after angioplasty is related to the procedure time These patients may be observed more closely for the development of immediate postprocedural ischaemic events.

Adult↗
PubMed2001

Lengthening of intraatrial conduction time in atrial fibrillation and its relation with early recurrence of atrial fibrillation.

Intraatrial conduction delay in atrial fibrillation (AF) that is considered a component of atrial electrical remodeling has been demonstrated previously in experimental models and it is considered an important factor for the induction or stabilization of AF. However, it is not known if this phenomenon exists in human AF. The present study aimed to compare intraatrial conduction time (IACT) in patients with chronic atrial fibrillation who were converted to sinus rhythm and a matched control group, and to investigate its relation with early AF recurrence. Seventeen patients with chronic AF (mean duration of 20.71+/-16.35 months) were enrolled in the study (7 males, 10 females, 63+/-8 years). An age and sex matched control group (n=12) consisted of patients with sinus rhythm who underwent electrophysiological study (EPS). None of the patients were on any antiarrhythmic treatment during the procedures. Cardioversion was performed via external DC cardioversion. Eight patients in the control group were delivered a DC shock because of induced ventricular tachycardia during EPS. IACT was defined as the interval between the onset of P wave surface ECG and the beginning of A wave at high right atrium (IACT 1) and low right atrium (IACT 2). Additionally, the interval between A wave at high right atrium and low right atrium was measured (IACT 3). Patient characteristics such as age, sex and echocardiographic variables were not different between the AF group and the control group. Heart rate after cardioversion was found to be similar between the two groups. Total delivered energy was significantly higher in the AF group than in the control group (464.47+/-165.82 joules vs. 315.00+/-27.77 joules, p<0.001). IACT 1 (15.30+/-7.61 msec vs 8.50+/-5.29 msec, p<0.02 ), IACT 2 (45.25+/-836 msec vs 26.44+/-10.45 msec, p<0.001) and IACT 3 (26.9+/-8.26 msec vs. 18.67+/-10.05, p<0.05) significantly lengthened in the AF group after maintenance of sinus rhythm compared to the control group. There were 6 early AF recurrences during the 1 week follow-up period. Multivariate analysis, revealed IACT 2 and IACT 3 were significantly different between the control group, the patient with recurred AF and the patients with maintained sinus rhythm. Post-hoc analysis revealed that IACT 2 and IACT 3 significantly lengthened in the patients with recurred AF compared to both the control group and patients with maintained sinus rhythm. On the other hand, only IACT 2 patients with maintained sinus rhythm were found to be higher than those of the control group. The present study indicated that intraatrial conduction was disturbed in patients with AF, a finding which is consistent with those of previous experimental studies. Additionally, such a phenomenon may be a risk factor for the early recurrence of AF after cardioversion to sinus rhythm.

Atrial Fibrillation↗
PubMed2000

Left atrial appendage function in patients with different pacing modes.

Many studies suggest that patients who receive a ventricular pacemaker have a higher incidence of systemic thromboembolism compared to patients receiving a physiological pacemaker. However, the exact mechanism regarding the etiology of thromboembolism remains unclear. We evaluated the left atrial appendage (LAA) functions, using multiplane transesophageal echocardiography (TEE), in patients with different pacing modes. In order to evaluate the ejection fraction (EF), peak emptying (V(E)) and filling (V(F)) flow velocities of the LAA by TEE, we studied 31 patients (mean age 63+/-18.5 years) who had been paced for 5.0+/-2.9 years. Patients with atrial fibrillation, left ventricular dysfunction and mitral valve disease were excluded. The pacing indications were complete atrioventricular block (AVB) in 19 patients (9 VVI, 10 VDD or DDD) and sick sinus syndrome (SSS) in 12 patients (5 VVI, 7 DDD). Mean EF, V(E) and V(F) of the LAA were significantly lower in all patients with ventricular pacing (25.5+/-15.6%, 30.4+/-15.6 cm/s and 29. 1+/-19.2 cm/s, respectively) compared to those with physiologic pacing (48.5+/-16.9%, 59.6+/-16.3 cm/s, 57.9+/-18.5 cm/s, respectively) (P<0.01 in all). When patients were further classified with respect to underlying heart disease whether they had SSS or AVB, all measurements of the LAA (EF, V(E) and V(F)) in both subgroup of patients with SSS and AVB were found significantly lower in those with ventricular pacing than in those with physiologic pacing (Tables 3 and 4). This decrease, especially in LAA flow, was much greater in those with SSS (Mean V(E) and V(F) <20 cm/s). In a patient paced with VVI for SSS, a thrombus was detected within the LAA cavity. In conclusion, these results suggest that the pacing modality appeared to influence the LAA functions in paced patients. Patients with asynchronous ventricular pacing modes had a significantly higher incidence of depressed LAA functions than did patients with physiological pacing, especially more marked in patients with sick sinus syndrome. This may be a factor responsible for increased risk of thrombus formation and thromboembolic events in this patient population.

Adult↗
PubMed2000

The effects of L-carnitine treatment on left ventricular function and erythrocyte superoxide dismutase activity in patients with ischemic cardiomyopathy.

We studied the effects of L-carnitine on left ventricular systolic function and the erythrocyte superoxide dismutase activity in 51 patients with ischemic cardiomyopathy. They all previously were under the treatment of angiotensin-converting enzyme inhibitor, digitalis and diuretics. Patients were randomized into two groups. In group I (n=31), 2 g/day L-carnitine was added to therapy. L-Carnitine was not given to the other 20 patients (Group II). In group I (mean age 64.3+/-7.8 years), 27 of the patients were men, and four were women. In group II (mean age 66.2+/-8.7 years), 17 of the patients were men, and three were women. Twenty age-matched healthy subjects (mean age: 60.1+/-5.3 years) constituted the control group. In each group, left ventricular ejection fraction (LVEF) by echocardiography and red cell superoxide dismutase activity by spectrophotometric method were measured initially and after 1 month of randomisation. Compared with normal healthy subjects (n=20), patients (n=51) had significantly higher red cell SOD activity (5633+/-1225 vs. 3202+/-373 U/g Hb, P<0.001). At the end of 1 month of L-carnitine therapy, red cell SOD activity showed an increase in group I (5918+/-1448 to 7218+/-1917 U/g Hb, P<0.05). In group II, red cell SOD activity showed no significant change after 1 month of randomisation (5190+/-545 to 5234+/-487 U/g Hb, P=0. 256). One month after randomisation there was a significant increase in LVEF in both groups I and II (37.8-42.3%, P<0.001 in group I; 41. 5-43.8%, P<0.001 in group II). The improvement in LVEF was more significant in the L-carnitine group (4.5% vs. 2.3%, P<0.01). We conclude that, as a sign of increased free radical production, superoxide dismutase activity was further increased in patients with L-carnitine treatment. L-Carnitine treatment in combination with other traditional pharmacological therapy might have an additive effect for the improvement of left ventricular function in ischemic cardiomyopathy.

Aged↗