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    Brain Malformations Associated With Knobloch Syndrome-Review of Literature, Expanding Clinical Spectrum, and Identification of Novel Mutations
    (Elsevier Science Inc, 2014) Caglayan, Ahmet Okay; Baranoski, Jacob E.; Aktar, Fesih; Han, Wengi; Tuysuz, Beyhan; Guzel, Asian; Guclu, Bulent
    BACKGROUND: Knobloch syndrome is a rare, autosomal recessive, developmental disorder characterized by stereotyped ocular abnormalities with or without occipital skull deformities (encephalocele, bone defects, and cutis aplasia). Although there is clear heterogeneity in clinical presentation, central nervous system malformations, aside from the characteristic encephalocele, have not typically been considered a component of the disease phenotype. METHODS: Four patients originally presented for genetic evaluation of symptomatic structural brain malformations. Whole-genome genotyping, whole-exome sequencing, and confirmatory Sanger sequencing were performed. Using immunohistochemical analysis, we investigated the protein expression pattern of COL18A1 in the mid-fetal and adult human cerebral cortex and then analyzed the spatial and temporal changes in the expression pattern of COL18A1 during human cortical development using the Human Brain Transcriptome database. RESULTS: We identified two novel homozygous deleterious frame-shift mutations in the COL18A1 gene. On further investigation of these patients and their families, we found that many exhibited certain characteristics of Knobloch syndrome, including pronounced ocular defects. Our data strongly support an important role for COL18A1 in brain development, and this report contributes to an enhanced characterization of the brain malformations that can result from deficiencies of collagen XVIII. CONCLUSIONS: This case series highlights the diagnostic power and clinical utility of whole-exome sequencing technology allowing clinicians and physician scientists to better understand the pathophysiology and presentations of rare diseases. We suggest that patients who are clinically diagnosed with Knobloch syndrome and/or found to have COL18A1. mutations via genetic screening should be investigated for potential structural brain abnormalities even in the absence of an encephalocele.
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    Evaluation of effects of memantine on cerebral ischemia in rats
    (Riyadh Armed Forces Hospital, 2008) Aluclu, Mehmet U.; Arslan, Seyfi; Acar, Abdullah; Guzel, Asian; Bahceci, Selen; Yaldiz, Mehmet
    Objective: To evaluate the effects of memantine on infarct size in cerebral ischemia and on neurological outcome after temporary middle cerebral artery occlusion (MCAO) and reperfusion in rats. Methods: In this study, performed between 2002-2004 in Dicle University School of Medicine, Diyarbakir, Turkey, 30 adult Sprague-Dawley rats were used. Cerebral ischemia was constituted by the intraluminal filament method with a 4-0 nylon suture. Reperfusion was started after 2 hours of MCAO. The rats were randomly divided into 2 groups as control and memantine. Saline 0.9% (0-5 ml/kg) and memantine (30 mg/kg) were administered via nasogastric intubations. Three coronal slices of 2 mm thickness were obtained from cerebrum, cerebellum, and brain stem, and were stained with a 2% solution of triphenyltetrazolium chloride. Transparent sheets were placed over each section and the areas of the brain and infarct were measured. Results: Forty-five slices from each group (total 90) were obtained. Percent of ischemic area (%) in cerebrum, cerebellum, and brain stem level in memantine was lower than those of the control group (p < 0.0001). In addition, we determined an improvement in neurological score at 24th and 72nd hours in the rats that have been given memantine. The memantine group showed significantly better recovery than the control group (p < 0.0001). Conclusions: We concluded that memantine may decrease ischemic area in experimental cerebral ischemia in rats and it seems that memantine may be beneficial in cerebral ischemia.
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    Pituitary adenoma coexisting with a suprasellar arachnoid cyst
    (Turkish Neurosurgical Soc, 2007) Guzel, Asian; Er, Uygur; Tatli, Mehmet; Uzunlar, Ali Kemal; Belen, Deniz; Bavbek, Murat
    OBJECTIVE: Biochemical and radiological properties of sellar and parasellar lesions are quite similar in some instances. This leads to a difficulty in preoperative diagnosis. Here, a pituitary adenoma and a suprasellar arachnoid cyst in the same patient is presented, and possible etiopathogenetic mechanisms and surgical treatment are discussed. CASE: A 56-year-old male patient was admitted to the hospital with a history of seizures, urinary incontinence and visual disturbances. Preoperative MRI revealed a mass lesion in the sella turcica with suprasellar extension and a coexisting large supra- and parasellar cyst. DISCUSSION and CONCLUSION: A slow-growing mass lesion beneath the defective mesencephalic leaf of the Liliequist membrane may lead to a one-way valve system on its surface. It might be speculated that CSF will become trapped in the cyst during tumor growth. The other possible mechanism to explain the coexistence is discussed. In light of these comments and intraoperative observations, we suggest a third type of suprasellar arachnoid cyst. a semi-communicative type.