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Biomedical subjects

Seiji Kikuchi

Publications and source records attributed to Seiji Kikuchi.

At least 37 records · Page 2Linked to original sources
PubMed2005

Herpes simplex virus encephalitis presenting with cerebral infarction-like signs and neuroimages.

A patient with an atypical presentation of herpes simplex virus (HSV) encephalitis mimicking acute cerebral infarction was reported. A 48-year-old man developed left-sided hemiparesis, convulsive seizures, and loss of consciousness. Brain magnetic resonance imaging revealed high intensity areas in the right frontal to parietal lobes on T2-weighted and diffusion-weighted images. Soon after admission with suspected cerebral infarction of the right middle cerebral artery region, the patient had high fever with frequent seizures and severe loss of consciousness. Laboratory findings including cerebrospinal fluid established a diagnosis of HSV encephalitis, and a state of apalic syndrome persisted despite aggressive antiviral therapy.

Brain↗
PubMed2004

CTLA-4 gene polymorphism is not associated with conventional multiple sclerosis in Japanese.

We investigated the polymorphisms of exon 1 (+49A/G) and promoter (-318C/T and -651C/T) regions of the CTLA-4 gene in 133 Japanese patients with conventional/classical multiple sclerosis (MS) and 156 healthy controls. Patients with optico-spinal MS (OSMS) or atypical clinical attacks were excluded from the study. There was no significant difference in the distribution of polymorphisms between patients and controls. Furthermore, there were no associations between polymorphisms and clinical characteristics, such as age at onset, disease prognosis, and HLA profiles. Our results suggest that CTLA-4 gene polymorphisms are neither conclusively related to susceptibility nor to the clinical characteristics of MS, especially in Japanese patients with conventional/classical form and clinical features identical to those of their counterparts in Western countries.

Adolescent↗
PubMed2004

Attack-related severity: a key factor in understanding the spectrum of idiopathic inflammatory demyelinating disorders.

Understanding the spectrum of idiopathic inflammatory demyelinating disorders (IIDD) is a fundamental issue for the diagnosis and treatment of these disorders as well as for the approach to their pathogenesis. The spectrum of IIDD is usually classified according to clinical course and lesion distribution. We compared the demographic features, clinical characteristics, laboratory findings, and genetic backgrounds between 193 Japanese patients with and without clinically or radiographically fulminant attacks who all satisfied the diagnostic criteria for multiple sclerosis (MS). "Fulminant attacks" in the current study represent attack-related clinically or radiologically severe relapses but do not necessarily mean severe disability. Patients with fulminant attacks were clinically and immunogenetically distinct from those free of such attacks, and the previously described characteristics of the opticospinal form of MS (OSMS) or neuromyelitis optica (NMO) were mostly shared by patients with fulminant attacks. HLA profiles were similar among patients with fulminant attacks irrespective of the lesion distributions. The GG homozygous and G alleles of the CTLA4 gene A/G coding SNP at position 49 in exon 1 were significantly more common in patients with fulminant attacks than in those without. Attack-related severity may be an important factor if validated by prospective studies defining criteria and establishing relationships to disease course and treatment regimens.

Adolescent↗
PubMed2004

Glyceraldehyde-derived advanced glycation end products in Alzheimer's disease.

The Maillard reaction that leads to the formation of advanced glycation end products (AGE) is considered to play an important role in the pathogenesis of Alzheimer's disease (AD). Until now AGE derived from glucose (glucose-AGE) have been mainly investigated, so we established new AGE species derived from alpha-hydroxyaldehydes and dicarbonyl compounds. We have found that AGE derived from glyceraldehyde (glycer-AGE) and glycolaldehyde (glycol-AGE) showed strong neurotoxicity for primary cultured rat cortical neurons in vitro. In this study, we immunohistochemically examined the localization of glycer-AGE and glycol-AGE in the brains of AD patients and elderly controls. Most of the neurons in AD or control brains did not show any immunoreaction with glycol-AGE. In AD brains, glycer-AGE was mainly present in the cytosol of neuron in the hippocampus and para-hippocampal gyrus, but not in senile plaques and astrocytes. The pattern of immunopositivity was uniform and powdery, not dot-like. The distribution of glycer-AGE differed from that of glucose-AGE, which was detected at both intracellular and extracellular sites. This suggests that glycer-AGE has a pathological role different from glucose-AGE in AD. In the central nervous system, glyceraldehyde is generated via the glycolytic pathway from glyceraldehyde-3-phosphate by glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We hypothesize that perikaryal glycer-AGE immunopositivity of neurons reflects an increase of cytoplasmic glycer-AGE along with the decline of GAPDH activity.

Acetaldehyde↗
PubMed2004

Platelet-activating factor acetylhydrolase gene polymorphism and its activity in Japanese patients with multiple sclerosis.

We evaluated the association of the plasma platelet-activating factor acetylhydrolase (PAF-AH) gene polymorphism (G(994)-->T) and PAF-AH activity with susceptibility and severity of multiple sclerosis (MS) in Japanese. DNA was collected from 216 patients with clinically definite MS (65 opticospinal MS (OS-MS) and 151 conventional MS (C-MS)) and from 213 healthy controls. The missense mutation G(994)-->T that disrupts the PAF-AH activity was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). No statistically significant difference in the frequency of genotypes and alleles of the plasma PAF-AH polymorphism was observed among OS-MS patients, C-MS patients and healthy controls. However, the missense mutation tended to be associated with the severity of OS-MS, especially in females (GT/TT genotypes; 51.7% in female rapidly progressive OS-MS vs. 26.6% in female controls, p=0.0870). Moreover, PAF-AH activities were significantly lower in MS than in controls, irrespective of clinical subtypes, among those carrying the identical polymorphism in terms of nucleotide position 994 of the PAF-AH gene. These findings suggest that the PAF-AH gene missense mutation has no relation to either susceptibility or severity of C-MS, yet its activity is down-regulated, and that the mutation has no relation with susceptibility of OS-MS, yet it may confer the severity of female OS-MS.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2004

Ibudilast, a nonselective phosphodiesterase inhibitor, regulates Th1/Th2 balance and NKT cell subset in multiple sclerosis.

We investigated the immunoregulatory effects of ibudilast, a nonselective phosphodiesterase inhibitor, at a clinically applicable dose (60 mg/day p.o. for four weeks) in multiple sclerosis (MS) patients. Sensitive real-time PCR for quantifying cytokine mRNA in the blood CD4+ cells revealed that the ibudilast monotherapy significantly reduced tumour necrosis factor-alpha and interferon (IFN)-gamma mRNA and the IFN-gamma/interleukin-4 mRNA ratio, suggesting a shift in the cytokine profile from Th1 toward Th2 dominancy. In a flow cytometric analysis, natural killer T cells, which have been reported to relate to Th2 responses in MS and its animal model (experimental autoimmune encephalomyelitis), increased significantly after the therapy. None of the significant immunological changes were seen in healthy subjects or untreated MS patients. Ibudilast may be a promising therapy for MS and its clinical effects warrant further study.

Adult↗
PubMed2004

Hodgkin's disease-related central nervous system angiopathy presenting as reversible posterior leukoencephalopathy.

Reversible posterior leukoencephalopathy syndrome (RPLS) is a clinical syndrome characterized by headache, conscious disturbance, seizure, and cortical visual loss with neuroimaging finding of edema in the posterior regions of the brain, with a reversible course (1). The precise pathomechanism of RPLS is not understood. However, association with uncontrolled hypertension, renal failure, eclampsia, or immunosuppressive agents has been implicated (1). We describe herein a case of Hodgkin's disease (HD)-related central nervous system (CNS) angiitis with neuroimaging finding suggestive of RPLS. The pathophysiology of RPLS in cases with CNS angiitis is discussed.

Adult↗
PubMed2004

Involvement of advanced glycation end-products (AGEs) in Alzheimer's disease.

The advanced stage of the glycation process (one of the post-translational modifications of proteins) leads to the formation of advanced glycation end-products (AGEs) and plays an important role in the pathogenesis of angiopathy in diabetic patients. It has recently become clear that AGEs also influence physiological aging and neurodegenerative diseases such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS). Recently we have provided direct immunochemical evidence for the existence of six distinct AGE structures within the AGE-modified proteins and peptides that circulate in the serum of diabetic patients on hemodialysis (DM-HD). We showed a direct toxic effect of the synthetic AGE-2 (glyceraldehyde-derived AGEs) on cortical neuronal cells and provided evidence for a toxic effect of AGE-2 present in DM-HD serum. These results indicate that of the various types of AGE structures that can form in vivo, the AGE-2 structure is likely to play an important role in the pathophysiological processes associated with AGE formation. In AD brains, AGE-2 epitope was mainly present in the cytosol of neurons in the hippocampus and para-hippocampal gyrus. Protein cross-linking by AGE structures results in the formation of protease-resistant aggregates. Such protein aggregates may interfere with both axonal transport and intracellular protein traffic in neuron. In this review, we provide an outline of AGEs formation in vivo and propose that the novel structural epitope AGE-2 is an important toxic moiety for neuronal cells in AD.

Alzheimer Disease↗
PubMed2004

[Treatment for patients with early Parkinson's disease].

Ad hoc committee of Japanese Neurological Society made a guideline for the treatment of Parkinson's disease in 2002. Based on the chapter of treatment for early Parkinson's disease, starting drugs were discussed in this article. Three points should be considered in initiating the drug treatment, that is, neuroprotection, motor complications, and side effects. In order to demonstrate neuroprotection of dopamine agonists by using neuroimaging techniques, CALM-PD CIT study (pramipexole) and REAL-PET study (ropinirole) were done. There are, however, many controversies concerning neuroprotection and no definite conclusion was drawn. On the contrary, the inhibitory effects of dopamine agonists on the appearance of motor complications were clearly elucidated by several large-scale studies. For the present, although the side effects were reported more frequently in those treated by dopamine agonists than by levodopa, starting the treatment by dopamine agonists were recommended except in patients with dementia and in elderly patients, for whom levodopa should be used first.

Aged↗
PubMed2003

The prevalence and clinical characteristics of MS in northern Japan.

In Japan, there is a low prevalence rate (PR) of multiple sclerosis (MS; 0.8-4.0/100,000) but a relatively high frequency of "optic-spinal form" MS (OS-MS). There have been no intensive epidemiologic frequency studies, however, in over 30 years. We performed a province-wide prevalence study of MS in the Tokachi province of Hokkaido, the northernmost island of Japan, and compared the observed clinical features with other populations in Japan and Western countries. Prevalence was determined on March 31, 2001. The primary sources for the case ascertainment were 13 hospitals that treated patients with neurologic diseases including MS in Tokachi. Patients were classified according to Poser's criteria. The prevalence rate of clinically definite or laboratory-supported definite MS (LSDMS) was 8.57 per 100,000 [31/361,726; male/female ratio=1:2.9, and age at onset=29.1+/-14.2 (mean+/-SD) years]. Out of the 31 patients, 5 (16%) were classified as OS-MS. The prevalence rate of MS in the Tokachi province was the highest reported in Orientals to date, although still low in comparison with Western communities at a similar latitude. In contrast to the previous reports in Japan, there was a relatively low frequency of OS-MS in Hokkaido.

Adolescent↗
PubMed2003

Deficits of working memory during mental calculation in patients with Parkinson's disease.

Using the dual task paradigm, previous studies have suggested that working memory (WM) deficit is due to depleted attention resources in patients with Parkinson's disease (PD). The aim of this study is to establish whether the WM problems in PD are due to reduced attentional set-shifting resources rather than depletion of attention resources. The task design attempts to eliminate confounding of the deficits in dealing with novel material, a problem documented in PD, by concentrating on WM tasks of mental calculation that are familiar to subjects in daily living. We also administered attention tasks, the Trail Making Test (TMT) that relies primarily on attentional set-shifting and the Kana (Japanese syllabogram) Pick-out Test instead primarily depending on depleted attention resources for allocation. A total of 24 patients with PD and 24 normal controls participated in this study. The PD group showed deficits in mental calculation span and in attentional set-shifting in the TMT-b.Considering the common deficits in alternating processing of mental calculation and TMT-b in PD, the results suggested that the central executive dysfunction in PD during mental calculations was due to reduced attentional set-shifting resources for rapidly alternating operations, rather than the depletion of attentional resources.

Adult↗
PubMed2003

The writing of arabic numerals, kanji, and kana in brain-damaged patients.

This study investigated the neural mechanisms involved in the writing of Arabic numerals, kanji, and kana. Tasks involving writing numerals in Arabic, kanji, and, kana were administered to four patients with Gerstmann's syndrome and to five Wernicke aphasics. The results indicated that the ability to write Arabic numerals was well preserved in the Wernicke aphasics despite their serious phonological disturbances. The patients with Gerstmann's syndrome, who have a deficit with the concept of number, could write kanji numerals better than Arabic and kana numerals. Unlike Arabic numerals (ideogram) and kana (syllabogram), kanji (morphogram) have both semantic and phonetic values. The results suggested that Arabic numerals may be somesthetic and linked directly to the concept of number bypassing phonological analysis.

Aged↗
PubMed2003

Effect of proteasome inhibitor on cultured mesencephalic dopaminergic neurons.

Proteasomal dysfunction has been implicated in the pathogenesis of Parkinson's disease (PD). We examined the effect of a selective proteasomal inhibitor, epoxomicin, on primary cultured mesencephalic neurons. Exposing rat cultured mesencephalic neurons to epoxomicin for 24 h resulted in neurotoxicity in a dose-dependent manner. Epoxomicin caused mitochondrial dysfunction, reduction in reduced glutathione (GSH), and increased generation of free radicals. Neuronal damage was significantly blocked by antioxidative/GSH-augmenting agents. Epoxomicin also increased the expression of Bax and decreased that of Bcl-2, which may cause mitochondrial dysfunction and release of free radicals. Dopaminergic neurons were preferentially resistant to the toxicity of epoxomicin. Inhibiting the synthesis of tetrahydrobiopterin (BH(4)), which has been reported to have antioxidative function, increased the susceptibility of dopaminergic neurons, whereas increasing BH(4) levels protected non-dopaminergic neurons. These findings suggest that BH(4) is at least in part a contributing factor to grand the resistance to dopaminergic neurons against epoxomicin neurotoxicity. Our results suggest that proteasome inhibition causes the neurotoxicity in mesencephalic neurons, but that is not sufficient to reproduce the selective damage to dopaminergic neurons, such as that seen in PD.

Animals↗
PubMed2003

Brefeldin A-induced neurotoxicity in cultured spinal cord neurons.

Brefeldin A (BFA) is a fungus metabolite that is known to cause the disassembly of the Golgi complex and apoptosis in exposed cells, both of which have been suggested as playing roles in the pathogenesis of neurodegenerative diseases, particularly amyotrophic lateral sclerosis (ALS). This study showed that BFA caused neurotoxicity and apoptotic nuclear changes in cultured spinal neurons of rat spinal cord in a dose- and time-dependent manner. The spinal motor neurons were more vulnerable to this neurotoxicity. The cultured spinal neurons showed irreversible disassembly of the Golgi apparatus as early as 1 hr after exposure to BFA. BFA induced the expression and activation of caspase-12 beginning 8 hr after exposure. The level of the cleaved form of caspase-3 had increased 12 hr after the addition of BFA. Free radical generation and loss of mitochondrial membrane potential were observed in the later stages of neurotoxicity caused by BFA. Collectively, our data suggests that BFA is an excellent agent for reproducing the pathophysiological features of ALS. This in vitro model may be useful in attempts to study the mechanisms of this neurodegenerative disease and to examine therapeutic potentials.

Animals↗
PubMed2003

Spinocerebellar ataxia type 14 caused by a mutation in protein kinase C gamma.

BACKGROUND: We previously discovered spinocerebellar ataxia type 14 (SCA14) in a single Japanese family with an autosomal dominant neurodegenerative disorder characterized by cerebellar ataxia and intermittent axial myoclonus. The latter manifestation is selectively observed in patients with early onset. We mapped the locus to chromosome 19q13.4-qter, but the etiologic gene was not known. Recently, a mutation in the protein kinase C gamma gene (PRKCG) was identified in a US family of English and Dutch ancestry with autosomal dominant SCA whose disease mapped to a region overlapping that of the SCA14 locus. Different PRKCG mutations were found in another family with SCA and in a sporadic case from the United States. Axial myoclonus was not observed in any of these US families. OBJECTIVES: To determine whether a mutation in the PRKCG gene is responsible for SCA14 and to investigate the prevalence of PRKCG mutations in Japanese patients with autosomal dominant SCA. PATIENTS AND METHODS: Direct nucleotide sequencing analysis of the 18 coding exons of the PRKCG gene was performed in the 19 members of the original Japanese family with SCA14 and in 24 Japanese probands with SCA. After identifying a PRKCG mutation, DNA samples from 72 patients with multiple system atrophy and 50 healthy individuals were examined for the mutation as controls. RESULTS: Sequence analysis revealed a novel missense mutation, Gln127Arg, in all affected members of the family with SCA14. This mutation was not found in 122 control individuals. No mutations in the PRKCG gene were detected in the group of 24 probands with SCA of unknown type. CONCLUSIONS: These findings document that SCA14 is caused by mutations in the PRKCG gene. The observation that all 4 PRKCG mutations identified in patients with SCA to date are located in exon 4 suggests a critical role for this region of the gene in cerebellar function. Mutations in the same region of the gene can result in myoclonus in some families but not in others.

Adult↗