Fumihito Yoshii

Positron emission tomographic studies during serial word-reading by normal and dyslexic adults.

Positron-emission tomography (PET) was used to study regional cerebral metabolic activity during oral reading in right-handed adult males with, and without a childhood and family history of developmental dyslexia. Significant group differences in normalized regional metabolic values were revealed in prefrontal cortex and in the lingual (inferior) region of the occipital lobe. Lingual values were bilaterally higher for dyslexic than normal readers. In contrast to the asymmetry observed in prefrontal and lingual regions in nondyslexic subjects during reading, the dyslexic pattern was more symmetric. These results demonstrate that individuals who suffered from familial developmental dyslexia as children, activate different brain regions during reading as adults, as compared to individuals without such childhood history.

A clinical and genetic study in a large cohort of patients with spinocerebellar ataxia type 6

AbstractIn order to clarify the clinical and genetic features of SCA6, we retrospectively analyzed 140 patients. We observed an inverse correlation between the age of onset and the length of the expanded allele, and also between the age of onset and the sum of CAG repeats in the normal and the expanded alleles. The ages of onset of four homozygous patients correlated better with the sum of CAG repeats in both alleles rather than with the expanded allele calculated from heterozygous SCA6 subjects. Clinically, unsteadiness of gait was the main initial symptom, followed by vertigo and oscillopsia, and cerebellar signs were detected in nearly 100% of the patients. In contrast, extracerebellar signs were relatively mild and infrequent. The results of neuro-otological examination performed in 22 patients suggested the purely cerebellar abnormalities of ocular movements in nature. There was a close relationship between downbeat positioning nystagmus (DPN) and positioning vertigo, which became more common in the later stage. We conclude that total number of CAG repeat-units in both alleles is a good parameter for assessment of age of onset in SCA6 including homozygous patients. In addition, clinical and neuro-otological examinations suggested that SCA6 is a disease with predominantly cerebellar dysfunction.

Mutation Analysis of the PINK1 Gene in 391 Patients With Parkinson Disease

OBJECTIVES To determine the frequency, distribution, and clinical features of Parkinson disease (PD) with PINK1 mutations. DESIGN Retrospective clinical and genetic review. SETTING University hospital. PATIENTS We performed extensive mutation analyses of PINK1 in 414 PD patients negative for parkin mutations (mean [SD] age at onset, 42.8 [14.3] years), including 391 unrelated patients (190 patients with sporadic PD and 201 probands of patients with familial PD) from 13 countries. RESULTS We found 10 patients with PD from 9 families with PINK1 mutations and identified 7 novel mutations (2 homozygous mutations [p.D297MfsX22 and p.W437R] and 5 single heterozygous mutations [p.A78V, p.P196QfsX25, p.M342V, p.W437R, and p.N542S]). No compound heterozygous mutations were found. The frequency of homozygous mutations was 4.26% (2 of 47) in families with autosomal recessive PD and 0.53% (1 of 190) in patients with sporadic PD. The frequency of heterozygous mutations was 1.89% (2 of 106) in families with potential autosomal dominant PD and 1.05% (2 of 190) in patients with sporadic PD. The mean (SD) age at onset in patients with single heterozygous mutations (53.6 [11.1] years; range, 39-69 years) was higher than that in patients with homozygous mutations (34.0 [20.3] years; range, 10-55 years). Myocardial iodine-123 metaiodobenzylguanidine uptake was low in patients with heterozygous mutations but not in those with homozygous mutations. CONCLUSIONS Our results suggest that homozygous PINK1 mutations tend to be diagnosed as the early-onset autosomal recessive form of PD. Single heterozygous mutations may contribute to the development of sporadic PD and also could be an additional genetic predisposition for developing familial PD. The reduced myocardial iodine-123 metaiodobenzylguanidine uptake observed in patients with single heterozygous PINK1 mutations is similar to that seen in patients with sporadic PD.

Viability of Neocortical Function Shown in Behavioral Activation State PET Studies in Alzheimer Disease

Twenty subjects with mildly to moderately severe Alzheimer disease (AD) and 14 normal elderly control subjects were studied using [18F]fluorodeoxyglucose and positron emission tomography (PET) to investigate regional cerebral glucose metabolism during both a resting state and a behavioral activation state, utilizing a reading memory task (RMT). The RMT produced significant global metabolic activation of 15 ± 15% in normal subjects and 11 ± 13% in AD subjects. The occipital regions were preferentially activated, but all regions in both groups were also significantly activated. The RMT did not allow a better discrimination of AD patients from normal controls on the basis of regional metabolic deficits. Regions in the AD group that were individually classified as hypometabolic during rest also exhibited metabolic activation. The apparent viability of hypometabolic regions in AD patients challenges current hypotheses regarding the cause of abnormal metabolism in AD.

Excessive daytime sleepiness and sleep episodes in Japanese patients with Parkinson's disease

In Parkinsons disease (PD), sudden unexpected sleep episodes and excessive daytime sleepiness (EDS) while driving and engaging in social activities are important problems. We conducted a multi-center study to clarify the prevalence and contributing factor of EDS and sleep episodes in Japanese patients with PD. We evaluated 188 patients with PD (85 men, 103 women) and 144 age-matched controls for sleepiness. EDS was defined as an Epworth sleepiness scale (ESS) score of >or=10. ESS score was significantly higher (6.6+/-4.2 vs. 5.6+/-3.8) and prevalence of sleep episodes was higher in PD than in controls (6.4% vs. 0.7%). PD patients with EDS were more likely to have sleep episodes (22.5% vs. 2.0%), higher score for disease severity and depressive symptoms, and on higher dose of dopaminergic agents than those without EDS. However, there were no differences in nocturnal disturbances between the two groups. ESS score was not different between patients taking ergot and non-ergot dopamine agonists. Logistic regression analysis demonstrated that mental state, total dose of dopaminergic agents, and ESS score were significant predictors of sleep episodes. ESS score of >or=10 had 75% sensitivity and 82.4% specificity for sleep episodes. These results suggest that sleepiness in PD is dependent on disease itself and dopaminergic treatment rather than nocturnal disturbances.

Characteristics of sleep disturbances in Japanese patients with Parkinson's disease. A study using Parkinson's disease sleep scale

The present multicenter cross‐sectional study was performed using semistructured questionnaires to determine the contributing factors of sleep disturbances in Japanese patients with Parkinsons disease (PD). We used the Parkinsons disease sleep scale (PDSS, Japanese version). All data were obtained by means of interviewed questionnaire and physical examination by neurologists. The study was carried out between April 2005 and December 2005 at eight university hospitals and affiliated facilities in the Kanto area of Japan. A total of 188 (85 men and 103 women) PD patients and 144 controls (64 men and 80 women) were included. Stepwise regression analysis identified complications of treatment, depression, age, and disease duration as significant risk factors of sleep disturbances in PD. Significant differences in total PDSS score were observed between Hoehn & Yahr (H&Y) Stages 1 and 4, between H&Y Stages 2 and 4, and between H&Y stages 3 and 4 (Bonferroni test). The results of this survey suggested that complications due to treatment (dyskinesia, wearing off, on–off), depressive state, and disease stage are significant determinants of sleep disorders in Japanese patients with PD. We speculate that the reduction of neurotransmitters involved in the sleep–wakefulness mechanism and degeneration of neurons progress together in parallel with deterioration of motor function.

Human task‐specific somatosensory activation

We used positron emission tomography to study normal patterns of local cortical metabolic activation induced by somatosensory stimuli. Palpation and sorting of mah-jongg tiles by textured design increased local glucose metabolic rate (ICMRgl), by 18% on average, in contralateral somatosensory cortex. A graphesthesia task gave a similar result. In contrast, vigorous vibrotactile stimulation of fingers, face, or knee did not produce a consistent focus of activation. Our results indicate that ICMRgl activation is best achieved by somatosensory tasks requiring an active perceptual effort.

Magnetic resonance imaging and 11C-N-methylspiperone/positron emission tomography studies in a patient with the interval form of carbon monoxide poisoning

Magnetic resonance (MR) and (11)C-N-methylspiperone ((11)C-NMSP)/positron emission tomography (PET) imagings were repeatedly performed in a 50-year-old man with the interval form of carbon monoxide (CO) poisoning. In MR images obtained when delayed neuropsychiatric symptoms developed (two months after poisoning), the inner segments of the bilateral globus pallidus appeared as high signal intensities in the T1-weighted and low signal intensities in the T2-weighted images, suggesting prior focal hemorrhage in these areas. A PET study with (11)C-NMSP performed at that time showed an increase in dopamine D2 receptor binding in the caudate and putamen. Treatment with bromocriptine was very effective and five months after the poisoning, MR and (11)C-NMSP/PET images showed improvement, concomitantly with the disappearance of the neuropsychiatric symptoms.

Correlation between depressive symptoms and nocturnal disturbances in Japanese patients with Parkinson's disease.

Depression and nocturnal disturbances are frequent in patients with Parkinsons disease (PD). The aim of this study was to determine the correlation between depressive symptoms and nocturnal disturbances in patients with PD in Japan. The subjects of this multi-center cross-sectional study were 188 patients with PD and 144 age-matched controls who were assessed for nocturnal disturbances by the Parkinsons disease sleep scale (PDSS) and for depressive symptoms by Zung Self-Rating Depression Scale (SDS). Depressive symptoms (SDS score of > or =40) were identified in 122 patients (64.9%). The SDS was significantly higher in PD patients than control subjects. The stepwise regression model identified PDSS (p<0.001) and Unified Parkinsons Disease Rating Scale I (mental state) (p=0.002) as significant determinants of SDS. Stepwise regression analysis identified item 15 (daytime sleepiness) (p=0.002), item 13 (early morning tremor) (p=0.008), item 12 (nocturnal dystonia) (p=0.015), and item 3 (sleep maintenance insomnia) (p=0.026) as significant predictors of SDS. Our results indicated that depressive symptoms in PD correlate significantly with nocturnal disturbances, and that daytime sleepiness, dystonia, tremor and sleep fragmentation are the most common nocturnal disturbances in depressed patients with PD.

A novel small molecule, N-(4-(2-pyridyl)(1,3-thiazol-2-yl))-2-(2,4,6-trimethylphenoxy) acetamide, selectively protects against oxidative stress-induced cell death by activating the Nrf2–ARE pathway: Therapeutic implications for ALS

Antioxidant defense is crucial in restoring cellular redox homeostasis. Recent findings have suggested that oxidative stress plays pivotal roles in the pathogenesis of many neurodegenerative diseases. Thus, an anti-oxidative stress remedy might be a promising means for the treatment of such disorders. In this study, we employed a novel ligand-based virtual screening system and identified a novel small molecule, N-(4-(2-pyridyl)(1,3-thiazol-2-yl))-2-(2,4,6-trimethylphenoxy) acetamide (CPN-9), which selectively suppressed oxidative stress-induced cell death in a cell-type-independent manner. CPN-9 upregulates NF-E2-related factor 2 (Nrf2), a key transcriptional regulator of the expression of phase II detoxification enzymes and antioxidant proteins, and Nrf2-regulated factors such as heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), and glutamate-cysteine ligase modifier subunit (GCLM). The CPN-9-mediated upregulation of HO-1, NQO1, and GCLM was abolished by Nrf2 knockdown. Moreover, the antioxidant N-acetylcysteine reduced the protective effect of CPN-9 against oxidative stress-induced cell death with concomitant diminishing of Nrf2 nuclear translocation. These results indicate that CPN-9 exerts its activity via the reactive oxygen species-dependent activation of the Nrf2 signaling pathway in cultured cells. It is noteworthy that the postonset systemic administration of CPN-9 to a transgenic ALS mouse model carrying the H46R mutation in the human Cu/Zn superoxide dismutase (SOD1) gene sustained motor functions and delayed disease progression after onset. Collectively, CPN-9 is a novel Nrf2 activator and a neuroprotective candidate for the treatment of neurodegenerative diseases, including ALS.