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Biomedical subjects

B Ozmen

Publications and source records attributed to B Ozmen.

9 recordsLinked to original sources
PubMed2006

A comparison of the effects of sequential transdermal versus continuous orally administered hormone replacement therapies on plasma total homocysteine levels in postmenopausal women: a randomized, placebo-controlled study.

OBJECTIVE: The objective was to determine the effects of transdermal and oral hormone replacement therapies on plasma total homocysteine levels in postmenopausal women. MATERIAL AND METHODS: One hundred and ten postmenopausal patients were enrolled in the study. Participants were randomized into three groups: in Group A (n = 31) oral continuous combined therapy and in Group B (n = 30) transdermal sequential hormone replacement therapy were given for 6 months. A placebo was administered orally to the control group (Group C, n = 30). Serum homocysteine levels were studied prior to and after 6 months of treatment in all groups. RESULTS: There were no statistical significant differences in mean serum homocysteine levels among the groups prior to the study. The mean homocysteine levels after 6 months in Groups A-C were also similar. CONCLUSIONS: Serum homocysteine levels alter with neither oral continuous nor sequential transdermal hormone replacement therapy.

Administration, Cutaneous↗
PubMed2004

Beta2-microglobulin and cystatin C in type 2 diabetes: assessment of diabetic nephropathy.

BACKGROUND: Changes in glomerular filtration rate (GFR) provide a valuable indicator of the progression of diabetic nephropathy (DN). This study was designed to demonstrate the clinical values of serum cystatin C (Cys C) and beta2-microglobulin in the assessment of renal function in type 2 diabetics by comparing them with the GFR, estimated from the uptake phase of 99 m technetium dimetiltriamino pentaacetic acid renogram (GFR-DTPA) and creatinine clearances. MATERIALS AND METHODS: 68 type 2 diabetic patients with (urinary albumin excretions (UAE) 30 - 300 mg/24 h) (n = 39) and without (UAE < 30 mg/24 h) (n = 29) microalbuminuria and 32 controls were enrolled in the study. Serum Cys C, beta2-microglobulin, creatinine, urinary microalbumin levels, creatinine clearances and GFR-DTPA values were determined in all groups. Non-parametric ROC curves, using a cut-off GFR-DTPA of 60 mL/min/1.73 m (2), were obtained for these markers. RESULTS: Serum Cys C, beta2-microglobulin, glucose and HbA1c concentrations were significantly higher in the group with diabetes compared to controls. In the patients with microalbuminuria, serum Cys C and glucose concentrations increased significantly in comparison to patients with normoalbuminuria, while no differences were observed for beta2-microglobulin levels. Serum creatinine concentrations, GFR-DTPA values and creatinine clearances were not different between both diabetic groups and controls. Cys C was positively correlated with beta2-microglobulin and creatinine and negatively with GFR values; beta2-microglobulin was also positively correlated with serum creatinine in microalbuminurics. A significant inverse correlation was found between beta2-microglobulin and GFR values in both microalbuminurics and normoalbuminurics. CONCLUSIONS: Increased Cys C and beta2-microglobulin in diabetics may be early indicators of incipient DN. The diagnostic accuracies of Cys C and beta2-microglobulin are superior to that of serum creatinine in distinguishing between mild and moderately reduced GFR.

Adult↗
PubMed2003

Depression and anxiety in hypothyroidism.

The aim of the study was to determine the prevalence and severity of depression and anxiety in patients with hypothyroidism and to compare this with euthyroid patients. Thirty patients with hypothyroidism and 30 euthyroid controls attending the Endocrinology outpatient department of Celal Bayar University, Medical Faculty were included in the study. The hormonal screening was done by immunoassay and haemagglutination methods. Then, for psychiatric assessment, Hospital Anxiety and Depression Scale (HAD), Hamilton Depression Rating Scale (HAM-D), and Hamilton Anxiety Rating Scale (HAM-A) were used. There was no difference between the two groups in terms of demographic features. Total scores obtained from the scales used in the study did not differ significantly (p > 0.05). The frequency of items of both HAM-D and HAM-A did not show any differences in the two groups. By Wilks' Lambda discriminant analysis, depressive mood (HAM-D#1) was found to be the discriminating feature between the hypothyroid group and the euthyroid group. Therefore, depression and anxiety were not outstanding features in hypothyrodism. However, depression was more significant in the hypothyroid than euthyroid group.

Adult↗
PubMed1997

Interaural delay-dependent changes in the binaural difference potential in cat auditory brainstem response: implications about the origin of the binaural interaction component.

Auditory brainstem responses (ABRs) evoked by dichotic clicks with 12 different interaural delays (ITDs) between 0 and 1500 microsecond(s) were recorded from the vertices of 10 cats under ketamine anesthesia. The so-called binaural difference potential (BDP), considered to be an indicator of binaural interaction (BI), was computed by subtracting the sum of the two monaural responses from the binaural one. The earliest and most prominent component of BDP was a negative deflection (DN1) at a latency between 4 and 4.8 ms. Like all the other components of BDP, DNI was also due to binaural reduction rather than enhancement of the corresponding ABR wave, P4 in this case. Furthermore, the way its latency increased as a function of ITD was also not compatible with what would be predicted by the delay-line coincidence detector models based on the excitatory-excitatory units in the medial superior olive (MSO). We therefore proposed an alternative hypothesis for the origin of this BI component based on the inhibitory-excitatory (IE) units in the lateral superior olive (LSO). The computational model designed closely simulated the ITD-dependent attenuation and latency shifts observed in DN1. It was therefore concluded that the origin of this BI component in the cat's vertex-ABR could be the lateral lemniscal output of the LSO, although the delay lines which have been shown to exist also in the mammalian brain may play an important role in encoding ITDs.

Acoustic Stimulation↗
PubMed1997

Lens lipid peroxides and glutathione concentrations in diabetic cataract.

This study aims to explore the role of reactive oxygen radicals in the genesis of diabetic cataract. Lipid peroxide (LPO) concentrations in senile (n = 30) and diabetic (n = 14) cataractous lenses, were determined as thiobarbituric acid-reactive substances (TBARS) by a method modified from Satoh and Yagi, and reduced glutathione (GSH) concentrations were measured according to Beutler. Lens LPO levels (mean, SD; nmol TBARS/g protein) were significantly higher in diabetics (107.54, 18.12) than senile cataractous subjects (53.54, 15.48) (P < 0.0001). Lens GSH levels (mean, SD; nmol/g protein) showed no significant difference between diabetics (4.29, 2.05) and senile cataractous subjects (4.68, 3.12). These results suggest that free radical damage is more effective in the genesis of diabetic cataract than in senile cataract.

Adult↗
PubMed1996

Human long-latency responses to brief interaural disparities of intensity.

The electroencephalographic responses to abrupt changes in interaural differences of time (ITD) and intensity (IID) should provide important information on the dynamic characteristics and integrity of the binaural mechanisms detecting the azimuthal shifts of a sound image. However, a change in either or both of these cues to sound lateralization would stimulate not only the binaural mechanisms but also the monaural ones. There are several reports evidencing that in the case of ITD changes this problem can be overcome by using time-shifted noise or repetitive clicks. Any change in IID, however, will inevitably have a stimulating effect also on purely monaural mechanisms. Therefore, the stimulation techniques described in the literature so far for recording the long-latency responses related to IID mechanism cannot be regarded as being specific for binaural mechanisms. We used dichotically presented 100/s click trains which were amplitude modulated with a random sequence of 50 or 100 ms square wave-intervals, so that the sound intensities at the two ears simultaneously alternated between 60 dB and 80 dB levels except during brief periods of time (50 ms) in which the interaural intensity balance was impaired, leading to an IID of 20 dB every 2 s. Owing to the fact that the cortical mechanisms remain unresponsive to repetitive stimuli presented with intervals shorter than a certain recovery period, this stimulus did not evoke any significant potential when it was presented monotically or diotically, yet it could produce lateral sound image shifts and therefore evoke pronounced long-latency responses when presented dichotically. The main components N1 and P2 of these shift responses and those of the pip responses, also recorded from the same subjects, were compared with respect to their midline distributions and hemispheric or bilateral asymmetries. The significant differences found between the shift and pip responses indicated that those evoked by the IID stimulation we designed should not be considered simply as a non-specific vertex potential.

Acoustic Stimulation↗
PubMed1992

Human long-latency potentials evoked by monaural interruptions of a binaural click train: connection to sound lateralization based on interaural intensity differences.

In 9 subjects with normal hearing, monaural offset (MO) responses in the long-latency range were recorded with and without an ongoing sound (click train at a rate of 250/s) at the opposite ear. In the latter case MOs were perceived simply as termination of a sound. In the former case, however, the abrupt transition from binaural to monaural (BM) stimulation was perceived as a shift of the fused image from the center to either side. Therefore, the fairly large difference potential obtained by subtracting the MO response from the BM response was evaluated as the cortical response to stimulation of the sound lateralization mechanism based on interaural intensity differences. These center-to-side responses, which could be characterized by an N1-P2 wave sequence at latencies of 120 and 220 ms, respectively, were compared with the auditory onset responses also recorded from the same subjects by means of a sequential stimulation paradigm. The scalp topography of the N1 components in all these responses recorded simultaneously from frontocentral, parietocentral and two superior temporal electrodes with a neck reference is discussed.

Acoustic Stimulation↗
PubMedDate not supplied

Electroencephalographic responses to briefly introduced interaural intensity differences.

The stimulation techniques so far described in the literature, for recording the long-latency electroencephalographic responses to changes in interaural intensity difference (IID), cannot be regarded as being specific for binaural mechanisms because any change in IID has inevitably a stimulating effect also on purely monaural mechanisms. However, by making use of the relatively long recovery characteristics of cortical responses we were able to design a novel IID-stimulus, which did not evoke any significant potential when it was presented monotically or diotically, yet produced lateral sound image shifts and therefore evoked pronounced long-latency responses when presented dichotically. The shift responses recorded from five subjects mainly consisted of a negative-positive wave sequence at latencies around 110 ms and 200 ms, respectively. These vertex potentials, which were tested in this work receive no significant contribution from the monaural or binaural mechanisms sensitive to overall sound intensity, should be useful as a diagnostic tool for assessing the level of maturation or the integrity of the sound lateralization mechanism based on IIDs.

Adult↗