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Y Yilmaz

Publications and source records attributed to Y Yilmaz.

At least 19 recordsLinked to original sources
PubMed2006

Dielectric study of neutral and charged hydrogels during the swelling process.

Dielectric spectroscopy measurements of conductivity were applied for understanding the change in the internal morphology of the neutral and permanently charged polyacrylamide (PAAm) hydrogels during the swelling process. For the first time four distinct peaks (each corresponding to a different swelling stage) in the conductivity of the neutral gel were observed during the swelling of this gel. These peaks are related to the distribution of dense polymer regions (they are defined as the "blobs") appearing in a microstructure of the given PAAm gel having at least four average sizes. For the charged gel the heterogeneity decreases due to the internal electric field of the charged sites. Thus, this characteristic behavior in the conductivity becomes almost negligible for the gel charged with permanent SO(3) (-) groups. It seems this fact causes considerable decrease in amplitude of the peaks and overall decrease the conductivity during the whole swelling process especially at high frequencies. The new theory of dielectric relaxation based on the fractional kinetics containing the complex power-law exponents was used for verifying these swelling processes and received an excellent confirmation in description of the real part of the complex conductivity Re[sigma(omega)] by the fitting function that follows from the suggested theory. The calculated power-law exponents describe the behavior of Re[sigma(omega,mm(0))] in the available frequency range (30 Hz-13 MHz) and for all values of the relative masses (volumes) measured in the process of the experiment. The excellent coincidence between the new theory and measured data gives a possibility to suggest more reliable physical picture of the swelling process that takes place in neutral/charged gels.

Journal Article↗
PubMed2006

Novel truncating and missense mutations of the KCC3 gene associated with Andermann syndrome.

BACKGROUND: Andermann syndrome (OMIM 218000) is an autosomal recessive motor-sensory neuropathy associated with developmental and neurodegenerative defects. The cerebral MRI reveals a variable degree of agenesis of the corpus callosum. Recently, truncating mutations of the KCC3 gene (also known as SLC12A6) have been associated with Andermann syndrome. METHODS: The authors assessed clinically and genetically three isolated cases from Germany and Turkey with symptoms consistent with Andermann syndrome. RESULTS: The authors detected four novel mutations within the KCC3 gene in their patients: two different truncating mutations in the first patient, a homozygous truncating mutation in the second, and a homozygous missense mutation in the third patient. In contrast to the classic phenotype of the Andermann syndrome linked to truncating KCC3 mutations the phenotype and the course of the disease linked to the missense mutation appeared to be different (i.e., showing additional features like diffuse and widespread white matter abnormalities). CONCLUSIONS: Not only truncating but also missense mutations of the KCC3 gene are associated with Andermann syndrome. Different types of KCC3 mutations may determine different clinical phenotypes.

Agenesis of Corpus Callosum↗
PubMed2006

Our experience in eight cases with urinary hydatid disease: a series of 372 cases held in nine different clinics.

OBJECTIVES: Hydatid disease, a parasitic infestation caused by the larval stage of the cestode Echinococcus granulosus, is diagnosed commonly in the east and south-east regions of Turkey. The aim of this study is to emphasize the relatively frequent occurrences of echinococcosis in our region, and to discuss therapeutic options and treatment results according to current literature. METHODS: A retrospective 10-year review of nine different clinics' records of the Research Hospital of the Medical School of Yüzüncü Yil University revealed 372 hydatid disease cases that were localized in various organs and treated surgically (271 cases) or drained percutaneously (99 cases). Hydatid disease was diagnosed by ultrasonography (US) and computed tomography scans (CT) and confirmed histopathologically. RESULTS: The involved organ was lung in 203 cases (131 adults, 72 children), liver in 150, spleen in 9, brain in 2, kidneys in 7 cases and the retrovesical area in 1 case. The urogenital system is involved at a rate of 2.15%. Two hundred and seventy-one cases were treated surgically and 99 percutaneously. Two cases with renal hydatid cyst refused the surgical procedure (one had a solitary kidney with hydatid cyst). Albendazole was administered to 192 patients; 93 patients had open surgical procedure and 99 patients underwent percutaneous procedure. Cysts were excised totally in the open surgical procedure; however, involved kidneys were removed totally (four cases) except one. Cystectomy and omentoplasty was performed in one case. Complications were as follows: in six cases, cystic material was spilled into the bronchial cavity during the dissection and a renal hydatid cyst ruptured and spilled retroperitoneally. CONCLUSION: Hydatid disease is a serious health problem in Turkey. The mainly affected organs are liver and lung. It can be treated surgical or by percutaneous aspiration.

Adult↗
PubMed2005

Massive ovarian oedema in adolescents.

Massive ovarian oedema is an unusual clinical entity occurring in teenage girls. It is a rare tumour-like condition of the ovary characterized by marked enlargement of one or both ovaries due to marked accumulation of oedema fluid in the ovarian stroma. Massive ovarian oedema may result from partial or intermittent torsion of the mesovary, interfering with venous and lymphatic drainage, but not with arterial blood flow. The patients most commonly present with lower abdominal pain and enlargement. This entity can clinically mimic a neoplasia. We report three cases with massive ovarian oedema.

Adolescent↗
PubMed2004

Increased QT dispersion in breath-holding spells.

AIM: Breath-holding spells are common in infancy and early childhood, and patients are frequently referred to paediatric cardiology clinics for exclusion of heart disease. Recent data reveal subsequent development of epilepsy and neurocardiogenic syncope. Autonomic dysregulation and increased vagal stimulation leading to cardiac arrest and cerebral ischaemia is considered as the cause. Iron deficiency anaemia may be associated with these spells. We studied QT dispersion for the assessment of ventricular repolarization in these patients. METHODS: The study group consisted of 19 girls and 24 boys between 3 and 108 mo of age (mean +/- SD = 22.7 +/- 17.7 mo); and the control group consisted of 13 girls and 12 boys between 3 and 57 mo of age (mean +/- SD = 22.9 +/- 15.1 mo). QT interval was measured; corrected QT interval (QTc), QT dispersion (QTd) and QTc dispersion (QTcd) were calculated from 12-lead surface electrocardiograms of the patients and the control group. RESULTS: There was no statistically significant difference in terms of QT and QTc intervals between patient and control groups, while QTd and QTcd values were significantly increased in patients with breath-holding spells compared to the healthy children. QT dispersion was 59.5 +/- 35.9 ms and 44.8 +/- 11.9 ms, respectively, in patients and controls (p < 0.05). QTc dispersion was 102.1 +/- 41.9 ms and 79.6 +/- 24.6 ms, respectively (p < 0.01). The presence of iron deficiency did not effect the QT and QTc dispersion. CONCLUSION: QT dispersion is increased in patients with breath-holding spells, and this finding justifies further investigation for rhythm abnormalities and autonomic dysfunction in this patient group.

Arrhythmias, Cardiac↗
PubMed2003

Increased QT dispersion in epileptic children.

AIM: Epilepsy is a common paroxysmal disorder in childhood. Tachyarrhythmia, bradyarrhythmia, asystole, atrioventricular block, ventricular fibrillation or sudden death may occur during seizures. Mutations of ion-channel coding genes are found in patients with idiopathic or cryptogenic epilepsy. The ion channels also play a role in arrhythmogenesis. QT dispersion is a non-invasive method for assessment of regional repolarization differences within the myocardial tissue. This study investigated QT and QTc dispersion (QTcd) and the risk of dysrhythmia in epileptic children. METHODS: The first group included 28 patients with newly diagnosed epilepsy and not taking antiepileptic treatment (range 10 mo to 15 y, mean +/- SD 6.86 +/- 3.92 y), the second group included 34 patients taking antiepileptic treatment (range 1-14 y, mean +/- SD 7.51 +/- 3.68 y) and the control group included 52 healthy children (range 4 mo to 15 y, mean +/- SD 6.94 +/- 3.92 y). Twelve-lead ECGs were obtained and heart rate, RR interval, P wave amplitude and duration, PR interval, QRS duration, QRS axis and QT intervals were measured, and QTc, QTd, QTcd were calculated in all subjects. The measurements were repeated in the first group under antiepileptic treatment. RESULTS: While no significant difference in terms of heart rate, RR interval, P wave amplitude and duration, PR interval, QRS duration, QRS axis, QT intervals or QTc intervals was found, QTd and QTcd values were significantly increased in epileptic children compared with the control group. QTd was 58.1 +/- 13.4 ms and 35.9 +/- 9.3 ms and QTcd was 91.0 +/- 22.9 and 68.6 +/- 18.0ms in patients and controls, respectively. Antiepileptic treatment did not affect QT dispersion. CONCLUSION: QT dispersion is increased in epileptic children. Further investigation is needed to reveal the pathogenesis of myocardial repolarization abnormalities in epileptic patients.

Anticonvulsants↗
PubMed2002

Slow regions percolate near glass transition.

A nanosecond scale in situ probe reveals that a bulk linear polymer undergoes a sharp phase transition as a function of the degree of conversion, as it nears the glass transition. The scaling behaviour is in the same universality class as percolation. The exponents gamma and beta are found to be 1.7 +/- 0.1 and 0.41 +/- 0.01 in agreement with the best percolation results in three dimensions.

Journal Article↗
PubMed2002

Luteinizing hormone pulse frequency and amplitude in azoospermic, oligozoospermic and normal fertile men in Turkey.

AIM: To investigate the LH pulse frequency and amplitude in azoospermic and oligozoospermic patients and to compare them with normal fertile subjects. METHODS: In this controlled clinical study, 10 normal fertile male volunteers and 20 infertile patients (10 oligozoospermic and 10 azoospermic) were enrolled. Blood samples were taken every 30 minutes for 12 hours. FSH, LH and T levels were determined. LH was observed at all the blood samples, but FSH and testosterone only at the first, middle and last samples. RESULTS: The mean LH levels were significantly different between all the groups, but there was no statistical difference in the FSH levels between the fertile and oligozoospermic groups. The mean LH levels increased from the fertile towards the azoospermic groups (P<0.01). The LH pulse amplitude and frequency were significantly different between all the 3 groups. The former increased while the latter decreased from the fertile to the azoospermic groups. The T levels were different statistically only between the fertile and the azoospermic groups. CONCLUSION: The more prominent is the testicular defect, the lower will be the LH pulse frequency and the higher the amplitude.

Adult↗
PubMed2001

Effects of sildenafil citrate, acetylcholine, and sodium nitroprusside on the relaxation of rabbit cavernosal tissue in vitro.

OBJECTIVES: To investigate the effect of sildenafil together with the influence of sodium nitroprusside and acetylcholine and further discuss its mechanism of action in vitro. METHODS: Isolated strips of rabbit corpus cavernosum were stimulated isometrically with phenylephrine. Graded relaxations were induced using increasing concentrations of acetylcholine, sodium nitroprusside, and sildenafil alone and in combination. RESULTS: The agents all relaxed the rabbit corpus cavernosal strips in a dose-dependent manner. The inhibitory potentials of the test agents were ranked (from least inhibitory to most inhibitory) as follows: sildenafil, acetylcholine plus sildenafil, sodium nitroprusside, sodium nitroprusside plus sildenafil, acetylcholine. The presence of sodium nitroprusside in the medium reduced the median effective dose for the sildenafil-induced relaxation of the cavernosal tissue from 3.65 x 10(-5) M to 2.73 x 10(-7) M, and the presence of acetylcholine reduced it to 9.79 x 10(-6) M. CONCLUSIONS: Sildenafil enhances the relaxing effect of both sodium nitroprusside and acetylcholine on the phenylephrine-induced contraction of rabbit cavernosal tissue.

Acetylcholine↗
PubMed2001

Cerebral vein thrombosis in Behçet's disease.

Behçet's disease is a chronic, relapsing multisystem disorder, and nervous system involvement is one of the serious manifestations. Neuro-Behçet is rarely reported in children and may present with a wide variety of symptoms because the entire neuraxis may be affected. A case of cerebral vein thrombosis secondary to Behçet's disease is presented. The patient has recovered without any visual loss and had no complaints at 1-year follow-up.

Adolescent↗
PubMed2001

Multicentral clinical evaluation of the aetiology of erectile dysfunction: a survey report.

Patients with erectile dysfunction, who admitted to 4 different urological centres in Turkey were evaluated in terms of aetiological factors to establish the aetiology of erectile dysfunction in our population and compare it with the data derived from Western communities. After the history, physical examination, psychological evaluation and laboratory testing, a clinical diagnosis was established as primarily psychogenic, organic, or mixed aetiology. Mean patient age was 43.5 years (range 17 to 69), and 9 of the patients were unmarried. Of the patients 53 had vascular risk factors, and 10 reported a history of alcohol abuse. Eleven patients were using drugs that might interfere with the disorder. In this multicentral study of 115 impotent men, an organic cause was found in 43%, psychogenic in 47%, and mixed in 19%. Mean age of the overall patients was 43.48. When the ages of the patients with organic erectile dysfunction and those with psychogenic erectile dysfunction were compared, it was clearly seen that those with organic erectile dysfunction were much older (52.73 versus 33.02).

Adolescent↗
PubMed2001

Magnetic resonance imaging findings in patients with severe neonatal indirect hyperbilirubinemia.

The aim of this study was to document the magnetic resonance imaging (MRI) findings of cases with a history of severe neonatal indirect hyperbilirubinemia. Ten cases (eight cases with neurologic findings, two normal cases) with a history of severe neonatal indirect hyperbilirubinemia were studied. Neurologic findings and MRI results were described and correlated. Seven of eight cases with neurologic findings demonstrated symmetric and uniform increased T2 signal changes limited to globus pallidi. MRI scans of two cases without neurologic findings showed no abnormality. Severe neonatal indirect hyperbilirubinemia should be considered in the differential diagnosis of bilateral symmetric hyperintense signal changes in the globus pallidus on MRI. However, high levels of unconjugated bilirubin concentrations in the neonatal period may not always cause such lesions of globus pallidus on MRI despite the presence of neurologic findings.

Child, Preschool↗
PubMed2001

Prognostic value of auditory brainstem response for neurologic outcome in patients with neonatal indirect hyperbilirubinemia.

To investigate the value of the auditory brainstem response as a reliable test for the neurologic prognosis of infants with neonatal indirect hyperbilirubinemia, auditory brainstem response studies were performed in 22 infants. The patients were followed up until 12 months of age. Two patients demonstrated pathologic auditory brainstem response consistent with auditory neuropathy but had no neurologic finding except a lack of speech at 12 months of age. Two other patients had neurologic sequelae, one showing severe dyskinetic cerebral palsy, the other mild hypotonia and motor retardation, but their auditory brainstem response results were normal. These results suggested that auditory brainstem response examination might not provide reliable information for the neurologic prognosis. Neurologic disturbances resulting from bilirubin neurotoxicity can be seen in patients with a normal auditory brainstem response, but patients with an abnormal auditory brainstem response may not have any neurologic dysfunction apart from speech retardation.

Bilirubin↗
PubMed2001

Comparison of acarbose and gliclazide as first-line agents in patients with type 2 diabetes.

AIM: To compare the effect of acarbose and gliclazide on clinical findings, biochemical parameters and safety in type 2 diabetic patients insufficiently controlled with medical nutrition therapy (MNT). METHODS: Seventy-two patients (age 35-70 years, BMI < or = 35 kg/m2), who had not taken any oral antidiabetic drug previously, were randomised into two groups after a four-week placebo period, and treated for 24 weeks with acarbose (100 mg two to three times daily) and gliclazide (40-80 mg twice daily). The study was open and 57 patients (33 males and 24 females) completed it. MNT was provided for each patient based on personal requirements as defined by a dietitian. The effect of treatment was evaluated by fasting and postprandial (PP) metabolic parameters (blood glucose, insulin and C peptide levels), HbA1c and plasma lipid levels. In addition, side-effects were recorded and clinical examinations performed. RESULTS: Both drugs were effective in reducing of HbA1c, fasting and PP blood glucose levels. However, PP serum insulin levels in the gliclazide group increased more than those in the group treated with acarbose (p = 0.007). Moreover, a small weight reduction was obtained with acarbose treatment but not with gliclazide. Lipid levels were favourably affected by both drugs. Total cholesterol levels decreased in both groups, the decrease only reaching significance in the acarbose group (p = 0.013). However, serum levels of LDL cholesterol decreased in both groups (acarbose and gliclazide, p = 0.033 and p = 0.023, respectively), but the ratio of HDL to LDL cholesterol increased in the acarbose group only (p = 0.045). Both treatments were generally well tolerated. Common complaints in the acarbose group were flatulence and meteorism (29.6%). However, 10.0% of the patients in the gliclazide group reported at least one mild hypoglycaemic episode. CONCLUSIONS: The results of the study demonstrate that acarbose and gliclazide were reasonably effective in improving metabolic control in patients insufficiently controlled with diet alone, and both treatments were well tolerated. Because of its effects on weight reduction and PP hyperinsulinaemia, acarbose may be preferred as a first-line drug, particularly in the treatment of overweight type 2 diabetic patients.

Acarbose↗
PubMed2000

99Tc-HmPAO SPECT in 13 patients with classic lissencephaly.

In this study, technetium-99 ((99)Tc)-hexamethylpropyleneamine-oxine single-photon emission computed tomography (SPECT) was performed on 13 children with classic lissencephaly (nine with epileptic seizures, four without seizures). Focal or multifocal hypoperfusions were observed in 12 patients. The hypoperfused areas observed on SPECT scanning did not correlate with the localization of agyric-pachygyric regions in all patients. The distribution of perfusion abnormalities by SPECT and the localization of agyria-pachygyria as detected by magnetic resonance imaging did not correlate strongly. All nine patients with seizures and three of the four patients without seizures had focal or multifocal cerebral blood flow abnormalities on the SPECT scans. The presence of brain perfusion abnormalities detected by SPECT and the occurrence of epileptic seizures did not have a significant relationship. These results suggest that the role of SPECT studies in classic lissencephaly is not clearly defined. More sophisticated methods are needed to clarify the correlation between structural and functional abnormalities of patients diagnosed with lissencephaly.

Brain↗
PubMed2000

Peroneal nerve palsy: the role of early electromyography.

Footdrop is rare in the newborn period. In this report, the clinical and electrophysiological features of a newborn whose peroneal neuropathy was detected in the delivery room is presented. Her first electrophysiological examination, at the 13th hour of life, revealed a peroneal nerve lesion. All findings elicited in this and subsequent examinations suggested an antenatal onset. Clinical recovery began within weeks of the birth and she was able to walk, with no residual neurological abnormality, by her first birthday. Early electrophysiological examination of a newborn with peripheral neuropathy may provide valuable information about the time of onset and pathophysiological features of the nerve lesion. In spite of the early electromyogram findings revealing severe nerve injury, a good prognosis is possible in newborns with peroneal neuropathy.

Diagnosis, Differential↗