Browsing by Author "Mavioglu H."

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    Visual evoked potentials in pregnancy
    (1999) Yilmaz H.; Erkin E.F.; Mavioglu H.; Sungurtekin Ü.
    Pregnancy is a period when the estrogen/progesterone ratio rises considerably because of the passage of estrogen from the placenta. These changes in the level of estrogen during pregnancy increase the sensitivity of the central nervous system to cathecholamines. As a result, the sensitivity of the receptors in both the visual cortex and the inner plexiform layer of the retina to dopamine increases, and transmission in the optic pathways becomes faster. Inspired by this knowledge, we studied monocular pattern-reversal visual evoked potentials (PRVEPs) in both eyes of 30 pregnant women in the first trimester and 30 healthy nonpregnant women in the reproductive age. Mean P100 latency of pregnant women was significantly shorter than mean P100 latency of nonpregnant women (p<0.001). Mean P100 amplitude values were higher in pregnant women, although not statistically significant (p>0.05). Plasma estrogen and progesterone levels of pregnant women showed a negative correlation with PRVEP latencies, but a positive correlation with PRVEP amplitudes. In conclusion, this study supports the impression that changes in the levels of sex steroids affect the formation of PRVEPs by their actions on the central nervous system. The increase in estrogen during pregnancy seems to facilitate neural transmission in the optic pathways. Rise in the estrogen-progesterone level might be responsible for the shorter PRVEPs latencies in pregnant women.
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    Effects of oestrogen replacement therapy on pattern reversal visual evoked potentials
    (2000) Yilmaz H.; Erkin E.; Mavioglu H.; Laçin S.
    As a result of a regression in the ovarian functions, oestrogen level in circulation during the menopause drops to 1/50 of its value in the normal reproductive cycle. Excitatory oestrogen increases the sensitivity of the central nervous system to catecholamines by changing the opening frequency of voltage-related L-type calcium channels and augmenting the effect of glutamate; in addition it inhibits the formation of gamma-amino butyric acid (GABA) by the inhibition of glutamate decarboxylase enzyme. It is argued that oestrogen increases transmission in the optic pathways and that oestrogen is responsible for the shorter latency values and higher amplitudes of visual evoked potentials in women. We recorded the monocular pattern reversal visual evoked potentials (PRVEP) of both eyes of 54 post-menopausal women before treatment and of 30 of them after replacement therapy with Tibolon, and of 24 women receiving placebo treatment. The explicit values of P100 latency of right and left eyes before treatment were 98.8 ± 3.5 and 99.0 ± 3.3 ms, respectively. The explicit values of P100 latency of right and left eyes after placebo treatment were 98.6 ± 3.7 and 98.8 ± 4.0, respectively. The explicit values of P100 latency of right and left eyes after replacement treatment were 94.6 ± 3.7 and 94.8 ± 4.0, respectively. We found a statistically significant decrease in the mean PRVEP latencies and a statistically significant increase in mean amplitudes after replacement treatment (P < 0.001) compared with those before treatment and those after placebo treatment. We attributed the changes in PRVEP values after replacement treatment to the action of Tibolon, which acted as a natural sex steroid and speeded the visual transmission time via the widespread receptors in the central nervous system. It is concluded that PRVEP is an objective electrophysiological assessment method in evaluating the efficiency of hormone replacement therapy in post-menopausal women.
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    Clinical and histological changes of intrathecally administered gadopentate dimeglumine (Gd-DTPA) in normal rats
    (Centauro SRL, 2005) Mavioglu H.; Tuglu I.; Temiz C.; Ozbilgin K.; Cilaker S.; Selcuki D.; Selcuki M.
    Objectives: This study is carried out to explore clinical and histological changes induced in rats by intrathecal administration of Gd-DTPA via suboccipital spinal injection. 2.5, 5, 10 μmol/g-brain of Gd-DTPA were injected intrathecally to 43 adult male rats and sucrose as control solution with same volume and osmolarity were injected to 18 rats. Animals were sacrificed on day 4 and 14. Sections from the cortex, brain stem, cerebellum and medulla spinalis were obtained to examine for cell loss and apoptosis. In this study, no clinical abnormalities were observed in 69.8% of rats of Gd-DTPA group and in 83.3% of rats of sucrose group. Transient neurological signs such as ataxia and paresis were seen in 11.6% of rats in the Gd-DTPA group and in 5.5% of rats in the sucrose group. They were seen more frequently in the Gd-DTPA group especially in the highest dose and volume. Histological examination did not revealed necrosis or apoptosis in both groups. This study suggests that intrathecally administered Gd-DTPA may be safe in humans when lower doses per gram of brain are used than rats.
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    The validity and reliability of the Turkish version of Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) in patients with mild and moderate Alzheimer's disease and normal subjects
    (2006) Mavioglu H.; Gedizlioglu M.; Akyel S.; Aslaner T.; Eser E.
    Objectives: The cognitive subscale of the Alzheimer's Disease Assesment Scale (ADAS-Cog) is the most widely used test clinical trials dealing with Alzheimer's disease (AD). The aim of this study was to investigate the validity and reliability of the Turkish version of ADAS-Cog. Methods: Twenty-nine patients with AD, fullfilling NINCDS-ADRDA criteria of probable AD, who were in stage 3-5 according to the Global Deterioration Scale (GDS), and 27 non-demented control subjects with similar age, gender and educational status were recruited for the study. The Turkish version of ADAS-Cog, Standardized Mini Mental Status Examination (MMSE) and Short Orientation-Memory-Concentration Test (SOMCT) were applied to both of the groups. Interrater reliability, internal consistency, test-retest reliability; face validity, differential validity and convergent validity were statistically analyzed. Results: Both MMSE and ADAS-Cog have significantly differentiated patients with AD and control subjects (p < 0.001). A significant correlation was established between MMSE and ADAS-Cog scores in AD group (r: -0.739). ADAS-Cog was also highly significantly correlated with GDS (r: 0.720) and SOMCT (r: 0.738). For the group with AD, control and whole cohort coefficients of internal consistency, Cronbach's α: 0.800, 0.515, 0.873 were found respectively. Inter-rater reliability for total ADAS-Cog score was found as ICC: 0.99 and 0.98 and test-retest reliability was found as ICC: 0.91 and 0.95 for demented and nondemented subjects, respectively. Conclusion: The Turkish version of ADAS-Cog has been found to be highly reliable and valid in differentiating patients with mild and moderate AD from nondemented subjects. Copyright © 2006 John Wiley & Sons, Ltd.
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    Familial Mediterranean fever gene variations could trigger VPS16-associated early-onset dystonia and diabetes mellitus: clinical identification of a family with MEFV and VPS16 genetic variation association
    (Oxford University Press, 2024) Gemici Y.I.; Ekici C.; Batum M.; Akbostanci C.; Koc A.; Mavioglu H.
    Objectives: We describe the clinical pictures of an index case with dystonia and his family resulting from VPS16 and MEFV genetic variations based on previously published data and discuss the mechanisms that may have brought out the clinical findings. Methods: A 17-year-old male had generalized dystonia that started at age 6 years, non-febrile abdominal pain attacks and was diagnosed with type 1 diabetes at age 14 years. Meanwhile, his 13-year-old sister had the same clinical presentation. His father was diabetic and his mother was asymptomatic. There was no consanguinity between the parents. Genetic variations were detected with whole exome sequencing. Results: VPS16 c.1513C>T/p.Arg505* (likely pathogenic), MEFV c.2080A>G p.Met694val (pathogenic) and MEFV c.1772T>C p.Ile591Thr (unknown significance) heterozygous variants were detected in his siblings. The father had VPS16 c.1513C>T/p.Arg505* and MEFV c.2080A>G p Met694val variations and the mother had MEFV c.1772T>C p.Ile591Thr variations. Conclusions: The occurrence of these diseases in siblings but their absence in the parents suggests the idea that the coexistence of two separate variations in the VPS16 and MEFV genes determines the phenotype. In addition, the increase in MEFV variation load in this family and the fact that DM occurs at an earlier age suggest that inflammation may cause an early diabetic clinical presentation. © The Author(s) 2024.