BACE1 modulates filopodia-like protrusions induced by sodium channel beta4 subunit

Processing of APP by BACE1 plays a crucial role in the pathogenesis of Alzheimer disease (AD). Recently, the voltage-gated sodium channel (Na(v)) beta4 subunit (beta4), an auxiliary subunit of Na(v) that is supposed to serve as a cell adhesion molecule, has been identified as a substrate for BACE1. However, the biological consequence of BACE1 processing of beta4 remains illusive. Here, we report the biological effects of beta4 processing by BACE1. Overexpression of beta4 in Neuro2a cells promoted neurite extension and increased the number of F-actin rich filopodia-like protrusions. While coexpression of BACE1 together with beta4 further accelerated neurite extension, the number of filopodia-like protrusions was reduced. Overexpression of C-terminal fragment of beta4 that was generated by BACE1 (beta4-CTF) partially recapitulated the results obtained with BACE1 overexpression. These results suggest that the processing of beta4 by BACE1 regulates neurite length and filopodia-like protrusion density in neurons.

Fibrillogenic nuclei composed of P301L mutant tau induce elongation of P301L tau but not wild-type tau

Frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), an autosomal, dominantly inherited neurodegenerative disorder caused by tau gene mutations, is neuropathologically characterized by intraneuronal filamentous inclusions of hyperphosphorylated tau protein. Biochemical and immunocytochemical analyses have shown that only mutant tau is deposited in patients harboring P301L missense mutation, whereas both wild-type and mutant tau are deposited in patients harboring R406W mutation (Miyasaka, T., Morishima-Kawashima, M., Ravid, R., Kamphorst, W., Nagashima, K., and Ihara, Y. (2001) J. Neuropathol. Exp. Neurol. 60, 872- 884 and Miyasaka, T., Morishima-Kawashima, M., Ravid, R., Heutink, P., van Swieten, J. C., Nagashima, K., and Ihara, Y. (2001) Am. J. Pathol. 158, 373-379). Here we have tested the nucleation ability of monomeric tau and the seeding ability of fibrillogenic nuclei obtained from bacterially expressed human tau. P301L mutant tau showed a higher nucleation ability than wild-type tau, whereas R406W mutant tau shows similar ability to wild-type tau. Surprisingly, fibrillogenic nuclei composed of P301L mutant tau enhanced the assembly of P301L mutant tau into filaments but did not promote filament formation from wild-type tau. In contrast, nuclei composed of R406W mutant tau supported filament formation from both wild-type tau and R406W mutant tau, as did nuclei composed of wild-type tau. Proteolytic analyses indicated that the substructure of nuclei composed of P301L mutant tau was different from that of nuclei composed of wild-type or R406W mutant tau. Thus, the interaction between fibrillogenic nuclei and monomeric protein appears to play an important role in the mechanism of tau filament assembly.

Beta-synemin expression in cardiotoxin-injected rat skeletal muscle

Background

β-synemin was originally identified in humans as an α-dystrobrevin-binding protein through a yeast two-hybrid screen using an amino acid sequence derived from exons 1 through 16 of α-dystrobrevin, a region common to both α-dystrobrevin-1 and -2. α-Dystrobrevin-1 and -2 are both expressed in muscle and co-localization experiments have determined which isoform preferentially functions with β-synemin in vivo. The aim of our study is to show whether each α-dystrobrevin isoform has the same affinity for β-synemin or whether one of the isoforms preferentially functions with β-synemin in muscle.

Methods

The two α-dystrobrevin isoforms (-1 and -2) and β-synemin were localized in regenerating rat tibialis anterior muscle using immunoprecipitation, immunohistochemical and immunoblot analyses. Immunoprecipitation and co-localization studies for α-dystrobrevin and β-synemin were performed in regenerating muscle following cardiotoxin injection. Protein expression was then compared to that of developing rat muscle using immunoblot analysis.

Results

With an anti-α-dystrobrevin antibody, β-synemin co-immunoprecipitated with α-dystrobrevin whereas with an anti-β-synemin antibody, α-dystrobrevin-1 (rather than the -2 isoform) preferentially co-immunoprecipitated with β-synemin. Immunohistochemical experiments show that β-synemin and α-dystrobrevin co-localize in rat skeletal muscle. In regenerating muscle, β-synemin is first expressed at the sarcolemma and in the cytoplasm at day 5 following cardiotoxin injection. Similarly, β-synemin and α-dystrobrevin-1 are detected by immunoblot analysis as weak bands by day 7. In contrast, immunoblot analysis shows that α-dystrobrevin-2 is expressed as early as 1 day post-injection in regenerating muscle. These results are similar to that of developing muscle. For example, in embryonic rats, immunoblot analysis shows that β-synemin and α-dystrobevin-1 are weakly expressed in developing lower limb muscle at 5 days post-birth, while α-dystrobrevin-2 is detectable before birth in 20-day post-fertilization embryos.

Conclusion

Our results clearly show that β-synemin expression correlates with that of α-dystrobrevin-1, suggesting that β-synemin preferentially functions with α-dystrobrevin-1 in vivo and that these proteins are likely to function coordinately to play a vital role in developing and regenerating muscle.

[A case of acute disseminated encephalomyelitis (ADEM) associated with peripheral neuropathy]

A 17-year-old boy with high fever, headache, and neck stiffness was admitted to our hospital. Spinal fluid showed a protein level of 215 mg/dL with myelin basic protein (579 pg/mL), 347/ microl cells (330 mononuclear cells), and a glucose level of 53 mg/dL. One week later, urinary retention, flaccid paraplegia, and sensory disturbance below the 10th thoracic level developed. MRI of the spinal cord revealed swelling and T2-high intensity area in the cord at the 11th and 12th thoracic level. Although high-dose of methylprednisolone was administered, consciousness disturbance and respiratory failure that required mechanical ventilation occurred. Bilateral abducens nerve palsy, nystagmus, and flaccid tetraparesis also occurred. Brain MRI revealed T2-high intensity area in the midbrain and pons. Nerve conduction study showed diminished amplitudes and prolonged latencies or absence of F waves. The patient was administered a combination of intravenous immunoglobulin and a high-dose of methylprednisolone. He showed improvement within one week after the treatment. Two weeks later, he recovered from respiratory failure and weakness of the upper limbs. He remained paraplegic, but gradually improved and was able to walk with support one and a half years later. We suggest the combination therapy of intravenous immunoglobulin and a high-dose of methylprednisolone is effective for patients with combined ADEM and peripheral neuropathy.

Sodium channel beta4 subunit: down-regulation and possible involvement in neuritic degeneration in Huntington's disease transgenic mice

Sodium channel beta4 is a very recently identified auxiliary subunit of the voltage-gated sodium channels. To find the primarily affected gene in Huntington's disease (HD) pathogenesis, we profiled HD transgenic mice using a high-density oligonucleotide array and identified beta4 as an expressed sequence tag (EST) that was significantly down-regulated in the striatum of HD model mice and patients. Reduction in beta4 started at a presymptomatic stage in HD mice, whereas other voltage-gated ion channel subunits were decreased later. In contrast, spinal cord neurons, which generate only negligible levels of expanded polyglutamine aggregates, maintained normal levels of beta4 expression even at the symptomatic stage. Overexpression of beta4 induced neurite outgrowth in Neuro2a cells, and caused a thickening of dendrites and increased density of dendritic spines in hippocampal primary neurons, indicating that beta4 modulates neurite outgrowth activities. These results suggest that down-regulation of beta4 may lead to abnormalities of sodium channel and neurite degeneration in the striatum of HD transgenic mice and patients with HD.

Upward gaze-evoked nystagmus with organoarsenic poisoning

The authors report assessment of abnormal ocular movements in three patients after organoarsenic poisoning from diphenylarsinic acid. The characteristic and principal sign is upward gaze-evoked nystagmus. Moreover, vertical gaze holding impairment was shown by electronystagmography on direct current recording.

Beta-site APP cleaving enzyme 1 (BACE1) is increased in remaining neurons in Alzheimer's disease brains

Alzheimer's disease (AD) is characterized by the extensive deposition of amyloid beta protein (Abeta) in the brain cortex. Abeta is produced from beta-amyloid precursor protein (APP) by beta-secretase and gamma-secretase. beta-Secretase has been identified as beta-site APP cleaving enzyme1 (BACE1). We produced rabbit polyclonal antibodies against the amino and the carboxyl terminals of BACE1. Using these antibodies, BACE1 was characterized in temporal lobe cortices by Western blotting and immunohistochemistry. Immunohistochemical studies employing anti-GFAP and anti-MAP2 antibodies as well as anti-BACE1 antibodies showed that BACE1 was expressed exclusively in neurons but not in glial cells. Brain samples were directly extracted by 0.5% SDS and analyzed by Western blotting and densitometer. Although the mean level of BACE1/mg protein in AD brains was not increased, the ratio of BACE1 to MAP2 or to NSE was significantly increased compared with that in control brains. Taken together, these findings suggest that those neurons that survive in AD brains might generate more BACE1 than normal neurons in control brains, indicating that increased BACE1 activity could be one of the causes of AD. This could justify the development of anti-BACE1 drugs for AD treatment.

Bladder and bowel dysfunction in chronic inflammatory demyelinating polyradiculoneuropathy

We present a patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) who developed severe bladder and bowel dysfunction (BBD) as evidenced by constipation, voiding difficulty, and urinary urgency. These symptoms appeared 10 years after onset of CIDP. Cystometry showed disturbance of bladder sensation and detrusor areflexia. Magnetic resonance imaging (MRI) showed greatly enlarged nerve roots filling the lumbosacral spinal canal; this appeared to be the likely cause of BBD. A 3-day course of intravenous methylprednisolone (1 g/day), followed by 30 mg/day of oral prednisolone, ameliorated the sensory disturbance and muscle weakness, but not BBD.

Decreased expression of hypothalamic neuropeptides in Huntington disease transgenic mice with expanded polyglutamine‐EGFP fluorescent aggregates

Huntington disease is caused by polyglutamine (polyQ) expansion in huntingtin. Selective and progressive neuronal loss is observed in the striatum and cerebral cortex in Huntington disease. We have addressed whether expanded polyQ aggregates appear in regions of the brain apart from the striatum and cortex and whether there is a correlation between expanded polyQ aggregate formation and dysregulated transcription. We generated transgenic mouse lines expressing mutant truncated N-terminal huntingtin (expanded polyQ) fused with enhanced green fluorescent protein (EGFP) and carried out a high-density oligonucleotide array analysis using mRNA extracted from the cerebrum, followed by TaqMan RT-PCR and in situ hybridization. The transgenic mice formed expanded polyQ-EGFP fluorescent aggregates and this system allowed us to directly visualize expanded polyQ aggregates in various regions of the brain without performing immunohistochemical studies. We show here that polyQ-EGFP aggregates were intense in the hypothalamus, where the expression of six hypothalamic neuropeptide mRNAs, such as oxytocin, vasopressin and cocaine-amphetamine-regulated transcript, was down-regulated in the transgenic mouse brain without observing a significant loss of hypothalamic neurons. These results indicate that the hypothalamus is susceptible to aggregate formation in these mice and this may result in the down-regulation of specific genes in this region of the brain.

Diphenylarsinic acid poisoning from chemical weapons in Kamisu, Japan

We noted a new clinical syndrome with prominent cerebellar symptoms in apartment building residents in Kamisu, Japan. The well that provided drinking water contained diphenylarsinic acid, a degradation product of diphenylcyanoarsine or diphenylchloroarsine, which were developed for use as chemical weapons, inducing severe vomiting and sneezing. Characteristics of diphenylarsinic acid poisoning include brainstem-cerebellar and cerebral symptoms. Mental retardation associated with brain atrophy in magnetic resonance images was evident in some infants. We must be vigilant to prevent or minimize the effects of further diphenylarsinic acid poisoning in Japan or elsewhere.

Pravastatin at 10 mg/day does not decrease plasma levels of either amyloid-β (Aβ) 40 or Aβ 42 in humans

It has been assumed that statins work as a preventative drug for Alzheimer's disease (AD). Although some epidemiological observations raise doubts to the effectiveness of statins for AD, many in vitro and clinical studies insist on the effectiveness of statins decreasing amyloid-beta (Abeta) levels in medium or blood. To explore the effect of pravastatin on Abeta production, we followed the longitudinal plasma levels of both Abeta 40 and Abeta 42 during the allocation of pravastatin in 46 patients with hyperlipidemia. We found no correlation between plasma cholesterol levels or the decreasing values of total cholesterol and those of Abeta 40 or Abeta 42. Patients having Apolipoprotein E4 (ApoE4) had higher low-density lipoprotein levels and lower Abeta 40 levels in plasma, suggesting ApoE4 seems to influence plasma Abeta levels via cholesterol metabolism.

Chrysamine G and its derivative reduce amyloid beta-induced neurotoxicity in mice

The neurotoxicity of amyloid beta (Abeta) is widely believed to play a seminal role in neurodegeneration in Alzheimer's disease. We examined the effect of Chrysamine G (CG) on such neurotoxicity using the specific measurement of surviving neurons. CG was found to reduce the neurodegeneration induced by both the active short fragment of Abeta(25-35) and full-sized Abeta(1-40). In this study, we synthesized a new chemical compound from a monovalent structure of CG (hCG), with a lower affinity for Abeta, and compared its activity with that of CG. Both CG and hCG were found to be equally efficacious in reducing Abeta-induced neuronal death at a concentration of 0.1-1 microM, indicating that the mechanism of action for CG was not due to its chelating activity, but rather due to its anti-oxidant activity.

Corticosteroid- responsive asymmetric neuropathy with a myelin protein zero gene mutation

A patient with hereditary neuropathy presented with asymmetric distal weakness. On nerve biopsy, there was demyelination and onion-bulb formation, and molecular analysis revealed that the patient was heterozygous for an MPZ mutation. The patient improved with corticosteroid treatment.

[A case of sensory perineuritis with Bowen disease]

A 60-year-old man was admitted because of subacutely progressive sensory disturbance characterized by fluctuating dysesthesia and light pain on the skin of his hands and feet. He exhibited mononeuritis multiplex, and a plaque with sloughing was observed on the left side of his back. Sural nerve biopsy revealed marked thickening of the perineurium with vascularization, and no necrotizing vasculitis. The pathological features of the nerve biopsy were compatible with sensory perineuritis. A biopsy from his skin lesion revealed Bowen's disease. There have been several reported cases of sensory perineuritis accompanied by malignant tumors. In these cases, immune dysfunctions were considered a common underlying cause in both diseases. This is the first reported case of sensory perineuritis associated with Bowen's disease.

Prednisolone (30-60 mg/day) for diseases other than AD decreases amyloid beta-peptides in CSF

The effect of corticosteroid on the concentration of amyloid beta-peptide (Abeta) in human CSF obtained from 16 patients without dementia treated with prednisolone (> or =30 mg daily) was studied. The concentrations of Abetax-40 and Abetax-42 in CSF decreased after treatment was started (p < 0.002). A moderate- or high-dose regimen of prednisolone decreases Abeta production or increases Abeta degradation in the human brain and deserves further study in AD.

Three-dimensional and fractal analyses of assemblies of amyloid beta protein subtypes [Abeta40 and Abeta42(43)] in canine senile plaques

The three-dimensional (3D) distribution of amyloid beta protein (Abeta) subtypes [Abeta40 and Abeta42(43)] in canine senile plaques (SP) was observed using a confocal laser scanning microscope. In diffuse plaques (DP), Abeta42(43) alone was deposited as an uneven nebula-like assembly of fine granules. The border of the Abeta42(43) assembly was unclear and diffusely merged to the surrounding area. Mature plaques (MP), on the other hand, showed two patterns of Abeta deposition. In some MP, only Abeta40 was deposited as a defined assembly of very short fibrillary structures. Other MP consisted of both Abeta40 and Abeta42(43), and the deposition patterns of the two Abeta species were the same as those in single-positive plaques; fine granular with unclear margin for Abeta42(43), and short fibrillary structures for Abeta40. Additionally, we calculated the fractal dimensions (FD) of both Abeta40 and Abeta42(43) assemblies, and examined the serial change of FD in each SP. The FD of Abeta42(43)-positive DP ranged from 1.05 to 1.27, and those of Abeta40-positive MP ranged from 1.13 to 1.54 in single-positive plaques. In one double-positive MP, FD ranged from 1.02 to 1.36 for Abeta42(43) and from 1.01 to 1.51 for Abeta40. These results showed that the FD of canine Abeta40 assemblies was higher than that of Abeta42(43) assemblies, and the spatial changes of FD values for Abeta40 and Abeta42(43) in double-positive plaques were quite different. These morphological analyses clearly showed that canine DP and MP have completely different 3D structures, suggesting that their processes of formation are different.

A case with myasthenia gravis (MG) emerging after splenectomy for idiopathic thrombocytopenic purpura (ITP): possible effects of thymectomy on autoantibodies

The combination of idiopathic thrombocytopenic purpura (ITP) and myasthenia gravis (MG) has been reported infrequently. We report here the development of MG in a patient who underwent splenectomy for ITP ten years earlier, and describe the serum levels of anti-acetylcholine receptor antibodies (anti-AchR) and platelet-associated IgG (PAIgG) followed over 11 years. The concentrations of both autoantibodies have been decreased after thymectomy, suggesting that this procedure is potentially beneficial for treating both MG and ITP.

Distinguishable effects of presenilin-1 and APP717 mutations on amyloid plaque deposition

Both APP and PS-1 are causal genes for early-onset familial Alzheimer's disease (AD) and their mutation effects on cerebral Abeta deposition in the senile plaques were examined in human brains of 29 familial AD (23 PS-1, 6 APP) cases and 14 sporadic AD cases in terms of Abeta40 and Abeta42. Abeta isoform data were evaluated using repeated measures analysis of variance which adjusted for within-subject measurement variation and confounding effects of individual APP and PS-1 mutations, age at onset, duration of illness and APOE genotype. We observed that mutations in both APP and PS-1 were associated with a significant increase of Abeta42 in plaques as been documented previously. In comparison to sporadic AD cases, both APP717 and PS-1 mutation cases had an increased density (measured as the number of plaques/mm(2)) and area (%) of Abeta42 plaques. However, we found an unexpected differential effect of PS-1 but not APP717 mutation cases. At least some of PS-1 but not APP717 mutation cases had the significant increase of density and area of Abeta40-plaques as compared to sporadic AD independently of APOE genotype. Our results suggest that PS-1 mutations affect cerebral accumulation of Abeta burden in a different fashion from APP717 mutations in their familial AD brains.

[A case of eosinophilic myositis proven by immunohistochemistry using antibodies against eosinophilic granule protein]

A 50-year-old man had been well until three months earlier, when he felt general fatigue, and cutaneous rash with itching. Thereafter a general muscular weakness developed and the patient could not walk for a month. Four weeks before referral to our hospital, he had high fever and could not role over in the bed. On admission, the patient was able to walk. He had no skin rash. Neurologically, he showed mild weakness in proximal muscles. Hematologic examination showed mild eosinophilia and serum creatine kinase was mildly elevated. Needle electromyogram revealed a diffuse myogenic pattern in extremities. Eosinophilic myositis was diagnosed by a biopsy of the left calf muscle showing mild infiltration of eosinophilis which was identified using antibodies against eosinophilic granule protein.

[Adult Sandhoff disease presented as a motor neuron disease phenotype with slow progression]

A 35-year old Japanese male with adult Sandhoff disease was described, who was presented as a motor neuron disease phenotype with slow progression. At the age of 15, he first noticed weakness in his thigh. At the age of 28, his upper and lower motor neuron disturbances were disclosed. He was diagnosed as atypical amyotrophic lateral sclerosis. At the age of 34, a slight sensory disturbance appeared in the lower extremities. When he was admitted to our hospital, he displayed marked atrophy and weakness in his quadriceps femoris muscles, but no signs of mental deterioration and cerebellar ataxia. Because of the atypical course of motor neuron disease, hexosaminidase activity in peripheral leukocytes was determined. The assay of total hexosaminidase, hexosaminidase A and hexosaminidase B activities demonstrated low levels of these activities (7-15% of controls), leading the diagnosis of Sandoff disease. He was a member of non-consanguineous family, and the abnormal patterns of hexasaminidase activities were different between his father and mother. These data appear to show that he is a compound heterozygote in the locus of the hexosaminidase B gene. This is the first Japanese case of adult Sanhoff disease presented as a motor neuron disease phenotype.

Cessation of cerebral hemorrhage recurrence associated with corticosteroid treatment in a patient with cerebral amyloid angiopathy

We report the case of a 65 year old female patient with biopsy-proven cerebral amyloid angiopathy (CAA). She experienced intracerebral hemorrhages 4 times during 23 days but these serious strokes did not recur after corticosteroid therapy was started and her condition greatly improved. Since high titers of antinuclear antibodies and elevated erythrocyte sedimentation rate were found in her serum, she may have an inflammatory disorder involving amyloid-laden cerebral vessels. This is the first report showing the usefulness ofcorticosteroid for the treatment of CAA-related cerebral hemorrhages. Additionally, the concentrations of Abeta40 and Abeta42 in the CSF of this patient decreased rapidly after the use of corticosteroid, and ultimately fell far below normal values.

Plasma levels of amyloid beta 40 and 42 are independent from ApoE genotype and mental retardation in Down syndrome

In Down syndrome (DS) brain an early, selective accumulation of amyloid beta (Abeta) peptides ending at residue 42 (Abeta42) occurs. Whether this event depends on an altered processing of amyloid beta precursor protein (APP) or on defective clearance is uncertain. To investigate this issue, we measured Abeta species 40 and 42 in plasma from 61 patients with DS, 77 age-matched normal controls, and 55 mentally retarded subjects without chromosomal abnormalities. The Abeta 40 and 42 plasma levels were then correlated with apolipoprotein E (apoE) genotypes in all groups of cases, and with I. Q. and Mini Mental Status Examination values in DS subjects. Both Abeta species were significantly elevated in DS compared to control groups, and the extent of their increase reflects that expected from APP gene overexpression. Plasma levels of Abeta 40 and 42 did not correlate with apoE genotypes in DS and control cases, and with the extent of mental retardation in DS subjects. The results indicate that accumulation and clearance of plasma and cerebral Abeta are regulated by different and independent factors.

Increased amyloid beta protein in the skin of patients with amyotrophic lateral sclerosis

Distinct vascular and periadnexal immunoreactivity have been observed for amyloid b protein (Abeta) in skin from patients with amyotrophic lateral sclerosis (ALS). We used an enzyme-linked immunosorbent assay to make a more quantitative comparison of Abeta concentrations between ALS patients and controls. The insoluble fractions of skin samples from ALS patients contained significantly higher Abeta concentrations per milligram protein than those from controls. Various alterations in extracellular matrix components have been reported to occur in the skin of patients with ALS, and several matrix constituents have been shown to affect processing and aggregation of Abeta in human brain. Taking these previous findings together with those of the present study, our observations suggest that changes in extracellular matrix in skin of ALS patients may facilitate aggregation and deposition of Abeta.

Apolipoprotein E allele-dependent antioxidant activity in brains with Alzheimer's disease

Thiobarbituric acid-reactive substances (TBARS), an index of lipid peroxidation, were assayed in postmortem brain. Basal TBARS levels were increased and oxidative stimulation produced more TBARS in AD relative to control brains. In addition, apolipoprotein E isoforms showed differing antioxidant activities, with E2 > E3 > E4, suggesting that the lowest antioxidant activity of E4 could contribute to its association with AD.

Novel presenilin-1 mutation with widespread cortical amyloid deposition but limited cerebral amyloid angiopathy

OBJECTIVE

To clarify the phenotypic heterogeneity in deposition of amyloid beta (Abeta) in the parenchyma and in cerebral vessels of the brains of the patients having presenilin-1 (PS1) mutations. Mutations in PS1 induce increased production of Abeta42(43), resulting in an enhanced overall deposition of Abeta protein within the cerebral cortex.

METHODS

Sequence analysis of the PS1 gene of DNA from patients with early onset Alzheimer's disease, and immunostaining of brain tissues by end specific monoclonal antibodies against Abeta.

RESULTS

Sequence analysis disclosed a novel mutation (N405S) in the PS1 gene in a Japanese patient with early-onset Alzheimer's disease. Postmortem examination of one patient with N405S showed limited cerebral amyloid angiopathy, whereas postmortem examination of another Japanese patient with Alzheimer's disease with the E184D mutation disclosed severe cerebral amyloid angiopathy. The brains of both patients showed widespread neuritic plaques, neurofibrillary tangles, and neuronal loss. Immunostaining showed that Abeta42 was predominant over Abeta40 in neuritic plaques in both patients, whereas Abeta40 was found to be predominant over Abeta42 in cerebral amyloid angiopathy in the patient with E184D. However, most cortical vessels of the patient with N405S were not reactive with either of the antibodies.

CONCLUSION

The N405S mutation of PS1 is a major determinant of cortical Abeta deposition but not cerebral amyloid angiopathy in Alzheimer's disease.

Abeta42-positive non-pyramidal neurons around amyloid plaques in Alzheimer's disease

Immunohistochemistry with end-specific antibodies against C-termini of Abeta40 and Abeta42 in Alzheimer's disease showed that Abeta42 immunoreactivity was localised intracellularly in subpopulations of neurons of patients with Alzheimer's disease.

Angiotensin-converting enzyme genotype is associated with Alzheimer disease in the Japanese population

We compared the distribution of an insertion (I)/deletion (D) polymorphism of the gene coding for the angiotensin-converting enzyme (ACE) in 133 Japanese sporadic Alzheimer disease (AD) patients with 257 controls. The association between AD and ACE genotypes or alleles was found to be significant. The frequency of II genotypes was 1.4 times higher in AD than controls, while that of DD genotypes was only 0.4 times as high. The altered distribution of ACE alleles in patients with AD appeared to be independent of apolipoprotein E.

A combination of autoimmune hepatitis, sensory-dominant peripheral neuropathy, and primary Sjögren's syndrome in the same patient: a rare association

Although autoimmune hepatitis and sensory-dominant neuropathy have been known to independently accompany primary Sjögren's syndrome, the combination of all these conditions in the same patient has not been described. We report the case of a woman who initially suffered from autoimmune hepatitis and later was diagnosed with primary Sjogren's syndrome upon the development of sensory-dominant neuropathy. In this patient, autoimmune hepatitis preceded neuropathy by one year. All of the diagnoses were confirmed by histological examinations of the liver, sural nerve, and minor salivary gland. Her autoimmune hepatitis was relieved with conservative treatment, and her sensory-dominant neuropathy was alleviated by prednisolone therapy. Our case indicated that the multiple organ involvement, especially that in the liver and peripheral nerves, should be taken into account in the course of primary Sjögren's syndrome.

[A case of stiff-man syndrome with head retraction like reflex myoclonus and jerky myoclonus of bilateral lower extremities which responded well to removal of mediastinal carcinoma]

A 58-year-old male presented with reflex myoclonus and stiffness of the left facial, tongue, shoulder, and lower limbs muscles. Muscle stiffness and gait progressively worsened, leading to frequent falls. Acoustic and cutaneous stimuli of head precipitated reflex myoclonus like head retraction. Cutaneous of lower extremities precipitated jerky myoclonus of bilateral lower extremities. CSF analysis were unremarkable. No anti GAD antibody or anti amphiphysin antibody was detected in the serum and CSF. On surface EMG the spasms initiated with 4-5 short burst discharges at intervals between 59 and 84 ms, followed by a tonic decrescendo activity up to 3 s. After diazepam treatment, stiffness and reflex myoclonus of lower extremities were disappeared and head retraction like reflex myoclonus was improved but remained. CT of the chest revealed a mediastinal tumor. Biopsy of the tumor revealed undifferential carcinoma. The patient further improved after the resection of the tumor. These findings suggest that this stiff-man syndrome may occur as an autoimmune paraneoplastic syndrome of CNS.

Alzheimer's disease: correlation of the suppression of beta-amyloid peptide secretion from cultured cells with inhibition of the chymotrypsin-like activity of the proteasome

Peptide aldehyde inhibitors of the chymotrypsin-like activity of the proteasome (CLIP) such as N-acetyl-Leu-Leu-Nle-H (or ALLN) have been shown previously to inhibit the secretion of beta-amyloid peptide (A beta) from cells. To evaluate more fully the role of the proteasome in this process, we have tested the effects on A beta formation of a much wider range of peptide-based inhibitors of CLIP than published previously. The inhibitors tested included several peptide boronates, some of which proved to be the most potent peptide-based inhibitors of beta-amyloid production reported so far. We found that the ability of the peptide aldehyde and boronate inhibitors to suppress A beta formation from cells correlated extremely well with their potency as CLIP inhibitors. Thus, we conclude that the proteasome may be involved either directly or indirectly in A beta formation.

[A case of delayed cerebral infarction occurring in puerperium preceded by herpes zoster ophthalmicus in late pregnancy]

Delayed central neurological symptoms following herpes zoster ophthalmicus (HZO) such as "herpes zoster ophthalmicus and delayed contralateral hemiparesis" are considered to be due to ipsilateral intracranial vasculopathy. We experienced a rare case with cerebral infarction occurred in puerperium following HZO in late pregnancy. A healthy 30-year-old woman had left HZO at weeks 35 of gestation. She was given acyclovir (ACV) for external use and improved with small pigmentation on the left eye-lid. Seven weeks after the onset of HZO, she suddenly developed aphasia and right hemiparesis. Cerebral angiogram showed narrowing on M 1 segment of the ipsilateral middle cerebral artery. The occlusion was seen on peripheral portion of the angular artery on the same side. In cerebrospinal fluid (CSF), cell count was slightly elevated, but concentration of protein and sugar were normal. Varicella-zoster titer was increased in both serum and CSF. She was treated with intravenous ACV (1500 mg/day) for 10 days. On the next day after the treatment, the cell count was normalized and on 18th day, varicella-zoster titer was decreased in CSF. Higher brain function improved and no relapses occurred. This is a first case of delayed cerebral infarction occurring in puerperium preceded by herpes zoster ophthalmicus in late pregnancy, as far as we searched. We should treat carefully pregnant or lactating patients with HZO, considering delayed cerebral infarction.