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Öğe Cerebral diffusional changes in the early phase of anthrax: Is cutaneous anthrax only limited to skin?(W B Saunders Co Ltd, 2006) Karakas, HM; Bayindir, Y; Firat, AK; Yagmur, C; Alkan, A; Kayabas, UObjectives. Characteristics of cerebral diffusion in the acute period of the anthrax infection were investigated to understand the pathophysiology of the disease. Methods. Six cutaneous anthrax patients (mean age: 33.3, SD: 18.1) and six healthy control subjects (mean age: 33.7, SS: 19.6) were examined at the acute phase of the infection with diffusion weighted imaging on 1.5 T scanner. ADC values were measured from five different cerebral locations. T-tests, Logistic regression and ROC curves were used. Results. Anthrax patients were significantly different than controls regarding cortical ADC values (p < 0.05). Logistic regression model accurately classified five out of the six anthrax cases (83.3%). A cut-off value of 574 mm(2)/s x 10(-3) was found by using ROC curve coordinates. A sensitivity of 100% and a specificity of 67% were attained by means of this value. Conclusions. This study shows the existence of cerebral parenchymal. changes at microstructural. level in cutaneous anthrax without neurological findings. These changes are possibly related to the components of the toxin. Our results support the general but unproven opinion that anthrax treatment does not change the existence and the effects of the toxin. Pathophysiological. mechanisms towards classification should therefore be reviewed. (c) 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved.Öğe Effect of nasal septal deviation on total ethmoid cell volume(Cambridge Univ Press, 2006) Firat, AK; Miman, MC; Firat, Y; Karakas, M; Ozturan, O; Altinok, TBackground: The aim of this study was to evaluate the effect of nasal septal deviation (NSD) on ethmoid cell volume and to determine whether there was any correlation between NSD grade and ethmoid cell volume. Methods: Forty computerized tomography (CT) scans from patients with rhinosinusitis symptoms with NSD were evaluated. Septal deviations were classified into three groups according to the degree of deviation on CT. Ethmoid cell volumes were measured and the relationship between NSD and ethmoid cell volume was investigated. Results: There was a moderate but significant negative correlation between the septal deviation angle and the percentage of the ethmoid cell volumes (p = 0.001, r = -0.5152, r(2) = 0.2654). Total ethmoid cell volume on the ipsilateral side compared with the contralateral side was found to decrease as the degree of NSD increased. Conclusions: Nasal septal deviation affects the total ethmoid cell volume of the nasal cavity. The results of our study underline the role of ethmoid cell volume in the compensation mechanism equalizing the nasal cavity airflow changes due to NSD.Öğe Protective role of melatonin in pinealectomized rat brains: in vivo magnetic resonance spectroscopic analysis(Wiley, 2005) Hascalik, S; Celik, O; Karakas, HM; Parlakpinar, H; Firat, AK; Ozsahin, MThe goal of this study was to investigate the effect of melatonin on basic cerebral metabolites in pinealectomized (Px) rat brains. Twenty-one rats were randomly divided into three groups with seven rats per group. The study groups included sham-operated rats, Px rats and Px rats treated with melatonin. Melatonin administration began at 60 days following pinealectomy and continued for 21 days. At the end of the study, in vivo single voxel magnetic resonance spectroscopy was performed on whole brains to determine choline (Cho), creatine and N-acetyl aspartate (NAA) concentrations. Px rats had significantly lower NAA levels (P < 0.05), and significantly higher Cho levels (P < 0.05) when compared with sham-operated rats. Administration of melatonin had normalized NAA and Cho levels in Px rats. We propose that pinealectomy causes significant changes in cerebral metabolites which are compatible with neural loss. Melatonin administration prevents the disruptive effects of pinealectomy on brain tissue.Öğe Quantitative evaluation of brain involvement in ataxia telangiectasia by diffusion weighted MR imaging(Elsevier Ireland Ltd, 2005) Firat, AK; Karakas, HM; Firat, Y; Yakinci, CObjective: To evaluate the value of diffusion weighted imaging (DWI) in diagnosing ataxia telangiectasia (AT) and to investigate the spatial distribution of cerebral microstructural changes caused by the disease. Methods: Six AT patients (9-13 years) and nine healthy control subjects were examined on 1.5 T scanner. In addition to conventional MR images, DWI were performed with a fat suppressed, multishot spin echo EPI sequence using B values of 0, 500 and 1000 s/mm(2). Mean ADC values were measured from 16 different supra and infratentorial location. The difference between controls and AT patients regarding ADC values, and the accuracy, sensitivity and specificity of them in discrimination were analyzed with t-tests, logistic regression analysis, ANOVA and ROC curves. Results: Conventional images of the controls were normal. In AT patients, the only conventional MR abnormality was cerebellar atrophy. The difference between both groups regarding mean ADC values was not significant for any of the cerebral structures. In contrary to cerebrum, cerebellar mean ADC values of patients and controls were statistically different (p < 0.011-0.0001). Patients and controls were classified with 100% accuracy using ADC values of cerebellar white matter and cortex together (p < 0.016). The cut-off ADC value (0.699 mm(2)/s) for middle cerebellar cortex had produced highest (100%) sensitivity and specificity. There was a difference between superior, middle and inferior cerebellar cortex regarding ADC values (p < 0.026). Superior cerebellar cortex (0.987 +/- 0.1956 mm(2)/s) had higher ADC values than the middle and inferior cerebellar cortex. Conclusion: DWI provides a supplementary and objective imaging finding in AT. This finding is highly accurate in the radiological discrimination of healthy subjects and AT. Our findings also implicate that AT causes a diffuse atrophy and mostly affects superior part of the cortex. (C) 2005 Elsevier Ireland Ltd. All rights reserved.Öğe Sonographic evaluation of the carpal tunnel after provocative exercises(Amer Inst Ultrasound Medicine, 2004) Altinok, MT; Baysal, O; Karakas, HM; Firat, AKObjective. Dynamic carpal tunnel syndrome (CTS) is a subtype of CTS in which symptoms usually subside with rest and return with repetitive motions. In this subgroup, nerve conduction studies, performed at rest, are often inconclusive. In this study, the diagnostic value of provocative sonography was evaluated in patients with dynamic CTS. Methods. Twenty wrists of 13 patients with dynamic CTS and 10 control subjects were investigated with sonography before and immediately after provocative exercises imitating work-related stresses. In addition to conventional indices (palmar displacement, nerve area at the middle level, and swelling ratio before and after exercise), 2 newly formed indices (provocative nerve area ratio and provocative palmar displacement ratio) were investigated. Results. In the pre-exercise period, there were no significant differences between patients and control subjects regarding palmar displacement and the swelling ratio. The difference was significant (P = .035) for the nerve area at the middle level. In the post-exercise period, all parameters were significantly different between patients and control subjects. The nerve area at the middle level and the swelling ratio had higher significance (P < .0001) than palmar displacement (P = .015). The post-exercise swelling ratio had the highest sensitivity (95%) in diagnosing dynamic CTS when a cutoff value of 1.26 was used. The provocative palmar displacement ratio had high sensitivity (80%) and the highest specificity (90%) for a cutoff value of 1.28. Conclusions. Provocative exercises increase sensitivity and specificity and contribute to the sonographic diagnosis of dynamic CTS. This examination should be performed if electrodiagnostic test results are negative.Öğe An unusual case of acute disseminated encephalomyelitis confined to brainstem(Elsevier Science Inc, 2004) Firat, AK; Karakas, HM; Yakinci, C; Altinok, T; Alkan, A; Biçak, UAcute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating disorder usually encountered in children or adolescents and characterized by multifocal neurological deficits of rapid onset. Typical target areas of demyelination include the corona radiata, centrum semiovale, periventricular white matter, cerebellar peduncles and brainstem. Involvement of deep gray matter nuclei is also frequent. We report a 6-year-old boy with ADEM who had only brainstem involvement. Serial magnetic resonance images representing the stage of disease and response to steroid treatment are presented. (C) 2004 Elsevier Inc. All rights reserved.
