A Valikovics

University of Debrecen, Debrecen, Hajdu-Bihar, Hungary

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Publications (28)98.61 Total impact

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    ABSTRACT: We report an unusual case of juvenile ischaemic stroke syndrome associated with the A8344G mutation in tRNA(Lys) gene of mitochondrial DNA. The clinical phenotype of patient was typical for MELAS (mitochondrial ecephalomyapathy with lactate acidosis and stroke like episodes). The MELAS has been related to mutation A3243G in most cases, but some other mitochondrial DNA mutations were described in the background of this syndrome as well. A 22-years-old man and his family were investigated. Throughout clinical investigation as well as Doppler sonography, neuroradiological, and immunserological examinations were performed. Molecular studies included the analysis of the Leiden, prothrombin G20210A and the most common mitochondrial DNA mutations. The DNA analysis of the proband revealed a heteroplasmic A8344G substitution in the T-loop of the tRNALYS gene. The mutation could not been detected in her mother blood. We can conclude that A8344G mutation of the mitochondrial DNA resulted in juvenile ischemic stroke, which is associated only rarely to this genetic alteration. In young age onset of a stroke-like episode with undetermined etiology the mtDNA alterations always have to be excluded.
    Ideggyógyászati szemle 11/2011; 64(11-12):399-403. · 0.35 Impact Factor
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    ABSTRACT: High stroke mortality in central-eastern European countries might be due to higher stroke incidence, more severe strokes or less effective acute care than in countries with lower mortality rate. Hospital databases usually yield more detailed information on risk factors, stroke severity and short-term outcome than population-based registries. The Debrecen Stroke Database, data of 8088 consecutively hospitalised patients with acute cerebrovascular disease in a single stroke centre in East Hungary between October 1994 and December 2006, is analysed. Risk factors were recorded and stroke severity on admission was scored by the Mathew stroke scale. The modified Glasgow outcome scale was used to describe patient condition at discharge. Mean age was 68+/-13 years, 11.4% had haemorrhagic stroke. The rate of hypertension on admission was 79% in men, and 84% in women, 40.3% of men and 19.8% of women were smokers, and 34% of all patients had a previous cerebrovascular disease in their history. Case fatality was 14.9%, and 43% had some disability at discharge. Outcome at discharge was worse with higher age, higher glucose, higher blood pressure, higher white cell count and erythrocyte sedimentation rate and more severe clinical signs on admission. In multivariate analysis admission blood pressure lost its significance in predicting outcome. In this large Hungarian stroke unit database hypertension on admission, smoking and previous cerebrovascular disease were more frequent than in most western databases. These findings indicate major opportunities for more efficient stroke prevention in this and probably other eastern European countries.
    International Journal of Stroke 10/2009; 4(5):335-9. · 2.75 Impact Factor
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    ABSTRACT: Human serum paraoxonase (PON1) protects lipoproteins against oxidation by hydrolyzing lipid peroxides in oxidized low-density lipoprotein (oxLDL); therefore, it may protect against atherosclerosis. PON1 activity and polymorphisms have been inconsistently associated with carotid artery disease. The goal of this study was to clarify the role of PON1 activity and phenotype on carotid artery disease and its correlation with some inflammatory and immune markers in subjects under 55 years with early-onset carotid atherosclerosis. Sixty patients with occlusive carotid artery disease and 30 healthy controls were enrolled. Intima-media thickness (IMT) was measured by high-resolution ultrasound of both common carotid arteries. Anti-oxLDL antibody levels were determined by ELISA. In the whole study population we found a negative correlation between PON1 activity and IMT (r = -0.27, p = 0.011), and between salt-stimulated PON1 activity and IMT (r = -0.24, p = 0.02). Both PON1 activity and salt-stimulated PON1 activity negatively correlated with anti-oxLDL levels (r = -0.28, p = 0.008; r = -0.26, p = 0.01). PON1 activity was lower in patients compared to controls; however, the difference was not significant.PON1 phenotype distribution of patients and controls did not differ significantly. The importance of PON1 activity as a predictive risk factor for early-onset occlusive carotid artery disease should be assessed in future studies.
    Cerebrovascular Diseases 02/2008; 25(1-2):122-8. · 2.81 Impact Factor
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    ABSTRACT: We tested if asymmetric dimethylarginine (ADMA) contributes to the simultaneous evolution of atherosclerosis and insulin resistance. We investigated the significant predictors of insulin resistance in the context of atherosclerosis, focusing on the role ADMA, symmetric dimethylarginine (SDMA), and l-arginine play in a cohort of young atherosclerotic patients and their age-matched controls. In a case-control study, 60 patients younger than 55 years having at least 30% stenosis of the internal carotid artery and 30 age- and sex-matched controls were recruited at a community-based neurosonologic laboratory. We found a strong positive association between the homeostasis model assessment of beta-cell function and insulin resistance and the ADMA/SDMA ratio that remained statistically significant even after adjusting for all significant and a priori identified determinants (beta = 6.76; 95% confidence interval [CI], 2.13-11.39; P = .005). Interestingly, this relationship was even more pronounced in the atherosclerotic stratum (beta = 8.29; 95% CI, 1.43-15.15; P = .019), whereas, on multiple linear regression, lack of association was seen in subjects free of carotid atherosclerosis (beta = 1.39; 95% CI, -5.46 to 8.26; P = .671). We conclude that ADMA/SDMA ratio is a significant determinant of insulin resistance and may be a better parameter to monitor than ADMA alone. By accounting for the competition at the y+ transporters, ADMA/SDMA ratio could be an indicator of intracellular ADMA level.
    Metabolism 04/2007; 56(3):394-9. · 3.10 Impact Factor
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    ABSTRACT: Asymmetric dimethylarginine (ADMA) assumes a significant role in atherosclerosis by inhibiting the endothelial nitric oxide synthase (eNOS). Moreover, ADMA inhibits the inducible NOS (iNOS), the isoform that triggers atherosclerosis via peroxynitrite formation. Therefore, we investigated whether ADMA is a risk or protective factor in the atherosclerotic process. Intima-media thickness (IMT) of the common carotid artery, a surrogate for vascular diseases, was chosen as the outcome variable of interest. Sixty patients younger than 55 years having at least 30% stenosis of the internal carotid artery and 30 age- and gender-matched controls were recruited at a community-based neurosonological laboratory. We investigated relatively young patients to circumvent the confounding effect age has in the development of atherosclerosis. The IMT showed a negative correlation with ADMA upon analysis of the pooled data (Spearman correlation coefficient -0.300, p = 0.0041) and the atherosclerotic stratum (Spearman correlation coefficient -0.323, p = 0.012). A multiple linear regression model containing all determinant factors of IMT previously identified by simple regression was used to further quantify the relationship between IMT and ADMA. The negative association between IMT and ADMA remained statistically significant (beta: -0.510, CI: -0.894, -0.127; p = 0.010), furthermore it was even stronger in the atherosclerotic stratum (beta: -0.67, CI: -1.16, -0.18; p = 0.008). A minimal increase in ADMA concentration may be protective by inhibiting iNOS but not eNOS in states where iNOS is induced, e.g. inflammation accompanying atherosclerosis.
    Cerebrovascular Diseases 02/2007; 23(5-6):388-94. · 2.81 Impact Factor
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    ABSTRACT: Inflammatory processes have importance in atherosclerosis. We evaluated if subjects below 55 years of age with occlusive carotid artery disease have higher serum levels of antibodies against oxidized LDL and endothelial cells and the chemokines MCP-1 and RANTES than age matched subjects without atherosclerosis. Sixty patients with occlusive carotid artery disease (stenosis or occlusion) and 30 age-matched controls participated in the study. We measured the degree of carotid artery stenosis and intima-media thickness (IMT) by duplex ultrasound. White blood cell count (WBC), C-reactive protein (CRP), and fibrinogen levels were significantly higher in patients (means+/-SD: 7.5+/-1.8 vs. 6.1+/-1.1 G/L, p<0.001; 7.7+/-20.7 vs. 2.5+/-1.9 mg/L, p=0.015; and 3.7+/-0.9 vs. 3.1+/-0.5 g/L, p<0.001, respectively). Antibody levels against oxidized LDL and endothelial cells (21.1+/-22.9 and 19.9+/-15.3 EU/mL, p=0.6; and 19+/-15 vs. 20+/-9 U/mL, p=0.07) and RANTES and MCP-1 levels (72.4+/-32.3 vs. 73.8+/-27.3 ng/mL, p=0.7; and 468+/-1041 vs. 318+/-131 pg/mL, p=0.7) did not differ significantly between patients and controls and did not correlate with IMT. Higher levels of WBC, CRP, and fibrinogen suggest an ongoing inflammation in early-onset carotid atherosclerosis, but increased IMT is not associated by the elevation of serum levels of chemokines and antibodies evaluated in this study.
    Cytokine 02/2007; 37(1):44-50. · 2.52 Impact Factor
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    ABSTRACT: Soluble CD40 ligand (sCD40L) has been suggested as a key mediator between inflammation and atherosclerosis, and the CD40-CD40L interaction has a role in atherosclerotic lesion progression. We evaluated if platelet released serum sCD40L and sCD40 levels differ between patients with early onset occlusive carotid artery disease and age-matched controls. sCD40L and sCD40 levels were measured in serum samples of 60 patients with occlusive carotid artery disease and 30 age-matched controls using ELISA. Degree of stenosis of the internal carotid artery (ICA), and intima-media thickness (IMT) in the common carotid artery were measured by high resolution ultrasound. Values are given as mean +/- SD. Mean age was 50.9 +/- 3.5 and 50.1 +/- 3.5 years in the patient and control groups. IMT was significantly thicker in patients than in controls (0.89 +/- 0.14 vs. 0.78 +/-0.12 mm, p=0.0003). Serum levels of sCD40L were significantly higher (6.9 +/- 5 vs. 4.5 +/- 3.0 ng/mL, p=0.038) in patients, whereas sCD40 did not differ significantly between patients and controls (85 +/- 56.9 vs. 79.3 +/- 18.7 pg/mL, p=0.34). IMT did not correlate with sCD40L or sCD40 levels (R=-0.03, p=0.77; and R=0.109, p=0.308, respectively). sCD40L but not sCD40 levels are significantly higher in patients with occlusive carotid artery disease. Platelet derived sCD40L may be a key mediator among inflammation, thrombosis and atherosclerosis.
    Disease markers 02/2006; 22(3):133-40. · 2.14 Impact Factor
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    ABSTRACT: Previously, 30 untreated hypertensive patients were investigated by transcranial Doppler (TCD) monitoring during physical exercise, and changes of hemodynamic parameters were compared with those of age matched healthy subjects. After 3-year antihypertensive (AHT) treatment, these hypertensives were investigated again. The aim of this study was to compare the cerebral hemodynamic changes in the regularly treated and noncompliant (untreated) hypertensives during ergometer cycling. Nineteen of 30 previously untreated hypertensive patients could be investigated again using the same method as before. Eleven were regularly treated (treated hypertensive [T-HT] group), and 8 did not take their AHT medications due to lack of compliance (noncompliant hypertensive [NC-HT] group). Blood pressure, heart rate, end-tidal CO2 (etCO2; Capnogard capnograph), and bilateral middle cerebral artery mean blood flow velocity (MV) were continuously monitored during ergometer cycling according to the World Health Organization protocol. Values of 2-minute loading were analyzed. Median loading time did not differ significantly between the T-HT and NC-HT groups. After 2 minutes of cycling in treated patients, the ratio of MV and etCO changes (DeltaMV/DeltaetCO2) showed similar values as before therapy (P = .38), whereas in noncompliant patients, a further worsening of the ratio of DeltaMV/DeltaetCO2 could be observed (P = .04). The decrease of arteriolar vasodilation (ie, the ratio of DeltaMV/DeltaetCO2) could be demonstrated in the NC-HT group after 3 years. TCD combined with ergometer cycling is a useful method for evaluation of cerebral hemodynamic changes after AHT therapy.
    Journal of Neuroimaging 02/2005; 15(1):64-9. · 1.41 Impact Factor
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    ABSTRACT: The role of serum cholesterol and triglycerides in carotid artery atherosclerosis is controversial. We measured carotid artery intima-media thickness (IMT), a marker of atherosclerosis in subjects younger than 55 years of age with a 6-fold range of serum cholesterol levels (3.93-25.03 mmol/L) and a 200-fold range of triglyceride levels (0.36-75.97 mmol/L). Eighty-six patients with increased serum lipid values and 30 subjects with normal lipid values were included. Serum lipids were measured after an overnight fast. High-resolution sonographic investigations of the carotid arteries of all patients were videotaped. Intima-media thickness was measured offline at 1-mm increments in the distal 10-mm segments of both common carotid arteries by a reader blinded to patient characteristics. First, IMT was compared among groups defined by their cholesterol and triglyceride levels with the use of traditional cutoff values. Next, all subjects were pooled, and general regression analysis was performed to identify significant predictors of IMT with age, body mass index, lipid values, sex, diabetes, hypertension, and smoking status as independent variables. Intima-media thickness was larger in patient groups with high cholesterol levels (ie, the hypercholesterolemic and combined hyperlipidemic groups) than in the control, borderline, and isolated hypertriglyceridemic groups (P < .01). In the general multiple regression model, IMT correlated positively with total cholesterol level (beta = 0.343; P = .002) and age (beta = 0.3; P = .006) but not with triglyceride level. Both the group comparisons and the general regression analysis of the pooled data suggest that hypercholesterolemia has an important role in early onset IMT changes in the common carotid artery, whereas hypertriglyceridemia does not have an appreciable role.
    Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 09/2004; 23(9):1161-9. · 1.40 Impact Factor
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    ABSTRACT: Several factors have been held responsible for the development of atherosclerosis. To avoid the masking effect of age, we evaluated correlates of carotid atherosclerosis in patients <55 years of age. Plasma lipids, oxidative resistance of low-density lipoprotein, homocysteine, inflammatory markers, plasma viscosity, and red cell deformability were measured in fasting blood samples of 100 subjects: 45 patients with >30% stenosis of the internal carotid artery, 20 patients with carotid occlusion, and 35 control subjects. Stenosis and intima-media thickness (IMT) of the carotid artery were evaluated by duplex ultrasound. White blood cell (WBC) count, plasma fibrinogen, C-reactive protein (CRP), and lipoprotein(a) levels were significantly higher in patients than in control subjects, and patients had increased IMT (P<0.01 for all comparisons). There was a tendency for higher homocysteine levels in patients. Smokers had higher WBC, fibrinogen, and CRP levels. After the effect of smoking was controlled for, WBC count, natural logarithmic transform of homocysteine, and online-measured IMT remained significantly higher in patients than in control subjects. WBC, fibrinogen, and CRP levels were highest in the highest IMT quartile (P=0.012, P=0.007, and P=0.036, respectively). Inflammatory markers and homocysteine have a more important role than lipid factors in early-onset carotid atherosclerosis. We cannot recommend the measurement of low-density lipoprotein peroxidation as a routine screening test to identify high-risk patients for early-onset carotid atherosclerosis. The confounding effect of smoking on inflammatory markers should be considered in studies on atherosclerosis.
    Stroke 01/2003; 34(1):58-63. · 6.16 Impact Factor
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    ABSTRACT: Ischaemic stroke ranks among the most important causes of death and disability in developed countries. Abnormal lipid metabolism is among the several factors that have a role in the pathogenesis of atherosclerosis. We hypothesize that the decreased resistance of low-density lipoproteins against oxidative stress is an independent risk factor for cerebral atherosclerosis and suggest testing this hypothesis by ultrasonographic evaluation of the carotid artery and correlating this finding to plasma values of compounds that play a role in lipid metabolism. By measuring the oxidative resistance of low-density of lipoprotein the risk for ischaemic stroke can be predicted.
    Medical Hypotheses 07/2001; 56(6):694-6. · 1.05 Impact Factor
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    ABSTRACT: To evaluate the diagnostic value of a combined method, i.e. ergometer cycling with continuous bilateral transcranial Doppler monitoring (TCD) to detect cerebral hemodynamic abnormalities in recently diagnosed hypertensive patients. 30 neurologically symptom-free, nontreated patients with essential hypertension and 30 age- and sex-matched controls were studied. Carotid ultrasound, resting ECG and blood parameters were investigated. Cycling ergometry was performed according to the WHO protocol. Blood pressure, heart rate, end-tidal CO2 (etCO2) and bilateral middle cerebral artery (MCA) blood flow velocity (MV) were monitored. At rest, MV in the MCA did not differ significantly between controls and hypertensive subjects. MV continuously increased in controls until the end of loading whereas a plateau was reached at 4 min in hypertensive subjects. During 6 min of cycling, the time course of absolute values of MV in the MCA and that of the changes in the ratio of mean velocity/end-tidal CO2 (DeltaMV/DeltaetCO2) differed significantly between hypertensive subjects and controls (p = 0.03 and p = 0.02, respectively). Ergometer cycling combined with TCD revealed altered vasoreactivity, therefore this may be a sensitive method for the detection of early hemodynamic impairment in nontreated hypertensive subjects.
    Cerebrovascular Diseases 02/2001; 12(3):186-91. · 2.81 Impact Factor
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    ABSTRACT: Cisternal samples of cerebrospinal fluid (CSF) were analyzed for protein, albumin, sodium (Na), potassium (K), and calcium (Ca) content in 21 control subjects and 64 patients who had experienced acute stroke. A second cisternal CSF sample was taken in 37 of the stroke patients after 2-3 weeks treatment with the calcium antagonist nimodipine. Increased permeability of the blood-brain barrier was reflected by the significantly higher CSF/serum ratio of albumin in stroke patients than in control subjects (0.0046 vs. 0.0028,p = 0.0012). Serum and CSF concentrations of Na, K, and Ca did not differ between control subjects and stroke patients. In control subjects and in stroke patients, concentration of calcium in cisternal CSF ([Ca]) was smaller than values reported by others in lumbar samples. In stroke patients, the pH of CSF was lower than that of simultaneously taken blood (7.38 vs. 7.44, p < 0.001). No differences between stroke patients and control subjects were found for the cisternal CSF/serum ratios of Na (1.0 and 0.99), K (0.61 and 0.63), and Ca (0.25 and 0.24). When patients and controls were pooled together, CSF total [Ca] correlated weakly with serum total [Ca] (Spearman r = 0.28, p = 0.014) and with serum ionized [Ca] (Spearman r = 0.27, p = 0.016). After 2-3 weeks of nimodipine treatment, CSF [Ca] was significantly lower in the subgroup treated with 60 mg nimodipine four times daily (240 mg/d) than with 30 mg four times daily. A nimodipine dosage of 30 mg four times daily (120 mg/d) did not affect CSF [Ca]. A 240 mg daily dosage, but not a 120 mg daily dosage, of nimodipine may affect the Ca transport system in humans at the choroid plexus.
    Clinical Neuropharmacology 10/2000; 23(6):318-23. · 1.82 Impact Factor
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    ABSTRACT: To investigate cerebral metabolism by 2-[18F]fluorodeoxy-d-glucose (FDG) uptake using PET and cerebrovascular reverse capacity by transcranial Doppler sonography (TCD) in different mitochondrial diseases (mitochondrial myopathy; mitochondrial encephalopathy, lactacidosis, and stroke-like episodes [MELAS]; and chronic external ophthalmoplegia). Previous studies on individual patients with mitochondriopathies revealed abnormal accumulations of mitochondria in endothelium, smooth muscle cells, and pericytes of blood vessels in different parts of the nervous system (cerebrum, cerebellum, sural nerve) and skeletal muscle. On this basis, some investigators suggested a pathogenic role of vascular involvement in the MELAS syndrome and other encephalopathies. smhd1 The authors investigated neuronal metabolism and cerebrovascular involvement with PET in 5 cases and with TCD with acetazolamide stimulation in 15 cases. The patients were divided into three groups: 1) interictal MELAS (n = 4); 2) progressive external ophthalmoplegia (n = 6); and 3) pure mitochondrial myopathy and neuropathy (n = 5). The results were compared with those from matched normal control subjects. The diagnoses were based on clinical phenotype as well as histopathologic and molecular analysis. Cerebral glucose uptake was impaired in all patients, both with and without CNS symptoms, particularly in the occipital and temporal lobes. The vasoreactivity of the small arterioles to acetazolamide did not differ significantly between the patients and healthy control subjects or between the different groups of mitochondrial disorders. MELAS does not appear to be a functional disturbance of arterioles leading to an ischemic vascular event. The clinical symptoms in MELAS are not the result of a mitochondrial angiopathy but are the consequences of a mitochondrial cytopathy affecting neurons or glia. There is no correlation between the decreased glucose metabolism and the duration of the disease.
    Neurology 09/2000; 55(4):544-8. · 8.25 Impact Factor
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    ABSTRACT: Cerebrovascular reactivity, cerebrovascular reserve capacity, and velocity acceleration can be easily and reliably assessed by measuring acetazolamide-induced changes using transcranial Doppler. The authors' aim was to determine whether there are gender-related differences in these parameters. Fifty-six healthy subjects (27 males, 29 females) were examined using transcranial Doppler. Velocities in the middle cerebral artery on both sides were recorded before and at 5, 10, 15, and 20 minutes after intravenous administration of 1 g acetazolamide. The baseline mean flow velocity in the middle cerebral artery was significantly higher in women than in men (p < 0.02). After acetazolamide administration, significantly higher cerebrovascular reactivity, cerebrovascular reserve capacity, and velocity acceleration were observed in females than in males (p < 0.001 in all cases). Subgroup analysis showed that women before menopause responded with higher cerebrovascular reserve capacity and velocity acceleration than age-matched men (p < 0.01 and p < 0.001, respectively), but no significant difference was found between females after menopause and men of similar age.
    Journal of Neuroimaging 08/2000; 10(3):151-6. · 1.41 Impact Factor
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    ABSTRACT: Because recent data are conflicting, it is not certain whether hyperlipidemia is an independent risk factor for cerebrovascular diseases. Decreased cerebrovascular reserve capacity refers to the decreased ability of the cerebral arterioles to adapt in critical conditions and probably predicts a higher risk of stroke. The aim of this study was to compare cerebrovascular reserve capacity in hyperlipidemic patients and healthy controls using transcranial Doppler sonography. Thirty-four hyperlipidemic patients and 21 healthy controls were examined. With transcranial Doppler sonography, the mean blood flow velocity in the middle cerebral artery was registered at rest and at 5, 10, 15, and 20 minutes after intravenous administration of 1,000 mg acetazolamide. Cerebrovascular reactivity and reserve capacity were calculated from mean blood flow velocities. Various laboratory measurements were also made and assessed for correlation with resting cerebral blood flow velocity and cerebrovascular reserve capacity. No significant differences could be observed between controls and hyperlipidemic patients in cerebrovascular reactivity or cerebrovascular reserve capacity. No correlation was found between various laboratory measurements and resting cerebral blood flow velocity or cerebrovascular reserve capacity. We could not demonstrate any differences in cerebrovascular reserve capacity between hyperlipidemic patients and healthy controls. Thus, the vasodilatory ability of the cerebral arterioles seems to remain unchanged in this patient group and is not correlated with the severity of hyperlipidemia.
    Journal of Clinical Ultrasound 04/2000; 28(3):115-21. · 0.70 Impact Factor
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    ABSTRACT: The aim of the study was to assess the incidence of atherosclerotic lesions on carotid arteries among diabetic subjects suffering from cerebrovascular accident. A further aim was to investigate the relationship between the severity of the carotid lesion, the stroke subtype and the fatal outcome. One hundred and sixty eight patients treated because of cerebrovascular accident at the Dept. of Neurology University Medical School of Debrecen were studied. The age of the patients, the duration of diabetes and hypertension were registrated. Base on duplex scanning carotid lesions were divided in 6 groups of severity (normal, intimal sclerosis, slight, moderately severe, severe stenosis and occlusion). Based on clinical signs and CT results stroke subtypes were divided into five groups (lacunar and non-lacunar infarctions, hemorrhages, normal CT and others). The relationship between severity of carotid lesions, stroke subtype and lethal outcome was assessed using statistical tests. Carotid stenosis of different severity was detected in 60% of the cases. Severity of stenosis was independent from duration of diabetes, but it was positively related to duration of hypertension (p = 0.016). In 1/3 of the patients lacunar strokes, in another 1/3 non-lacunar strokes were observed. No significant relationship was found between severity of carotid stenosis, stroke subtype and lethal outcome of the patients (p = 0.53 and p = 0.26 respectively). Diabetic patients suffering from stroke have a higher incidence of carotid artery atherosclerotic lesions than diabetics without stroke. A special attention should be paid to the carotid duplex sonography in order to detect diabetic cerebral macroangiopathies in early, asymptomatic stage.
    Orvosi Hetilap 04/1999; 140(13):697-700.
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    ABSTRACT: Strokes caused by hemodynamically significant internal carotid artery stenoses and occlusions are believed to be embolic or hemodynamic of origin. The aim of the study was to assess cerebral hemodynamic compromises of significant carotid artery stenosis of occlusion using vasodilatory testing (acetazolamide test) in asymptomatic and symptomatic patients. 36 patients with unilateral, hemodynamically significant carotid stenosis were investigated using transcranial Doppler acetazolamide-test. There were 12 asymptomatic and 24 symptomatic patients. The middle cerebral artery mean blood flow velocity was measured at rest and after intravenous injection of 1 g acetazolamide. The absolute mean blood flow velocities and the cerebrovascular reactivity was compared at the stenotic and non-stenotic side. In a further analysis the mean velocities and the cerebrovascular reactivity values of the stenotic side were compared. Results of acetazolamide test performed on 28 healthy volunteers were used as control values. There were no side-differences between the middle cerebral artery mean blood flow velocity and cerebrovascular reactivity values in the asymptomatic group. In the symptomatic group, however middle cerebral artery mean velocity and cerebrovascular reactivity after acetazolamide was significantly lower on the stenotic side, than on the non-stenotic one. Comparing the different groups non-stenotic sides did not differ to each other in their cerebral blood flow velocity and cerebrovascular reactivity. In the symptomatic patients, however, cerebral blood flow velocity and cerebrovascular reserve capacity after acetazolamide was lower, than that of the stenotic side of asymptomatic patients and controls. The transcranial Doppler is a suitable method for detecting altered cerebral hemodynamics in significant carotid stenosis. Impaired cerebrovascular reactivity may refer to the impairment of cerebral autoregulatory mechanisms.
    Orvosi Hetilap 04/1998; 139(11):623-8.
  • American Journal of Physiology-heart and Circulatory Physiology - AMER J PHYSIOL-HEART CIRC PHY. 01/1998;
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    ABSTRACT: The early preclinical detection of cerebrovascular complications in individuals with diabetes is one of the goals of care described in the St. Vincent Declaration. In accordance with this goal, the aim of the present work was to investigate whether altered cerebral microvascular function in patients suffering from type 1 diabetes can be detected with a transcranial Doppler probe after the administration of acetazolamide. A total of 72 type 1 diabetic patients and 40 healthy control subjects entered the study. Patients were divided into two groups: those with long-term diabetes (disease duration of >10 years, n = 37) and those with short-term diabetes (disease duration of < or =10 years, n = 35). Mean blood-flow velocity in the middle cerebral artery (MCAV) was measured at rest and at 5, 10, 15, and 20 min after intravenous administration of 1 g acetazolamide with a transcranial Doppler probe and expressed as the percentage change from the pretest measurement. The percentage increase in MCAV (cerebrovascular reactivity) was calculated at each time point and compared between the groups. Cerebrovascular reserve capacity (CRC), expressed as the maximal percentage increase of the MCAV, was compared between the groups. Additionally, a reproducibility study of CRC was performed in 10 patients, using intraclass correlations. Cerebrovascular reactivity in the long-term diabetes group was lower (means +/- SD: 5 min, 23.4 +/- 15.4%; 10 min, 28.8 +/- 17.0%; 15 min, 30.0 +/- 15.6%; 20 min, 24.2 +/- 17.8%) than that of the control subjects (5 min, 43.5 +/- 23.9%; 10 min, 55.3 +/- 24.0%; 15 min, 56.7 +/- 23.8%; 20 min, 54.8 +/- 25.9%) and the short-term diabetic patients (5 min, 43.6 +/- 25.9%; 10 min, 52.2 +/- 27.7%; 15 min, 55.3 +/- 32.2%; 20 min, 45.8 +/- 35.8%). CRC was lower in the long-term diabetes group than in the control group or the short-term diabetes group. Impairment of cerebrovascular reactivity was associated with retino- and nephropathy and increased levels of fibrinogen. In contrast, CRC was independent from actual glucose, insulin, glycosylated hemoglobin, von Willebrand factor antigen, and alpha-2 macroglobulin levels. Transcranial Doppler measurements of the changes in MCAV after stimulation with acetazolamide can detect altered cerebral microvascular function in patients with diabetes. Cerebrovascular reactivity and reserve capacity are reduced in patients with long-term diabetes. Further prospective studies should delineate the clinical significance of our results.
    Diabetes 11/1997; 46(11):1840-5. · 7.90 Impact Factor