Analysis of the expression level of alpha-synuclein mRNA using postmortem brain samples from pathologically confirmed cases of multiple system atrophy.

To determine whether multiple system atrophy (MSA) is associated with altered expression levels of the alpha-synuclein messenger RNA (mRNA), we performed quantitative reverse transcription polymerase chain reaction for alpha-synuclein mRNA using postmortem brain samples from 11 cases of MSA and 14 age-matched control subjects. The brain specimens used in this study contained both the gray matter and white matter, which were dissected from the frontal, temporal or occipital lobe. The expression levels of alpha-synuclein mRNA in the brain specimens of MSA cases were not different from those of the control subjects. These results suggest that the transcriptional regulation of the alpha-synuclein gene is unlikely to be affected in MSA brains.

No mutation in the entire coding region of the alpha-synuclein gene in pathologically confirmed cases of multiple system atrophy.

To determine whether mutations in the coding region of the alpha-synuclein gene are relevant in cases of multiple system atrophy (MSA), detailed nucleotide sequence analysis of the alpha-synuclein gene was performed using total RNA obtained from autopsied brain specimens of 11 pathologically confirmed cases of MSA. The brain specimens used in this study contained both gray and white matter, which were dissected from the frontal, temporal or occipital lobe. No nucleotide alterations were found in the entire coding region of the alpha-synuclein gene in any of the cases. While mutations in the regulatory or intronic regions of the gene were not ruled out, our results suggest that mutations in the coding region of the alpha-synuclein gene are unlikely to contribute to the pathogenesis of MSA.

[The role of apolipoprotein E in the pathogenesis of Alzheimer disease].

Alzheimer disease (AD) is by far the most common cause of dementia in humans. Massive accumulation of senile plaques and neurofibrillary tangles are characteristic neuropathological manifestations of the disease. Recent investigations have revealed the presence of apolipoprotein E (apoE) in these structures. Furthermore, APOE4, a specific allele of the apoE gene, is frequently associated with sporadic AD and late-onset familial AD. Now, APOE4 has been established as being a major risk factor for AD. Although apoE is one of numerous plasma lipoproteins, it is of particular interest because, unlike other lipoproteins that are mainly synthesized in the liver, apoE is also synthesized in astrocytes and oligodendrocytes in the central nervous system. Furthermore, apoE plays an important role in the regeneration and degeneration of neurons. Recent studies have indicated the possibility that APOE4 accelerates the deposition of amyloid beta protein, which is a major component of senile plaques in AD brains.

Autosomal dominant diffuse Lewy body disease.

We describe a Japanese family with parkinsonism and later-onset dementia. The proband developed parkinsonism at the age of 61 years, followed by dementia starting when she was 67. Her uncle, who was also her husband, died at the age of 78 years after 7- and 5-year histories of parkinsonism and dementia, respectively. Pathological examination of these two patients showed marked neuronal loss with Lewy bodies (LBs) in the brain stem pigmented nuclei and numerous cortical LBs and ubiquitin-positive hippocampal CA2/3 neurites were observed. The proband also had many amyloid plaques. Their two sons developed similar parkinsonism at the ages of 39 and 28 years and also suffered later-on-set dementia. The apolipoprotein E genotype of the proband, her uncle and one of their sons was epsilon3/4 and that of the other son was epsilon4/4. These findings strongly suggest that this family has autosomal dominant diffuse LB disease.

[A case of dural arteriovenous malformation associated with progressive dementia showing marked improvement with endovascular treatment].

An 81-year-old man was admitted with a 3-month history of progressive dementia. Neurological examination revealed marked dementia, parkinsonism and myoclonus in his extremities. His cerebrospinal fluid examination was normal. An electroencephalogram showed a mildly slowed background. Computed tomography (CT) disclosed diffuse low-density areas in bilateral cerebral white matter. Contrast-enhanced CT demonstrated vermiform enhancement of engorged cortical veins, suggesting increased pressure of the venous system. Magnetic resonance imaging (MRI) disclosed diffuse high-intensity areas in bilateral cerebral white manner on T2-weighted images, and abnormal flow-voids presenting venous congestion on proton-density images. Cerebral angiography revealed arteriovenous malformation (AVM) fed by four branches of the right external carotid artery with retrograde drainage into the right transverse sinus, superior sagittal sinus, and dilated cortical veins. The ipsilateral sigmoid sinus was not visualized. After transarterial embolization, transvenous embolization of the right transverse sinus was performed. These treatments resulted in a marked clinical improvement. We emphasize the role of AVM as a cause of progressive dementia.

Apolipoprotein E epsilon4 allele and progression of cortical Lewy body pathology in Parkinson's disease.

To elucidate whether the apolipoprotein E epsilon4 allele (APOE4) affects cortical neuropathology in Parkinson's disease (PD), we determined APOE genotypes and quantified the densities of cortical Lewy bodies (LBs), amyloid plaques and neurofibrillary tangles in 22 autopsy-proven PD cases (12 with dementia; 10 without dementia) that were not accompanied by Alzheimer's disease. The APOE4 frequency in the demented patient group was 0.21, which was significantly higher than that in Japanese controls (P < 0.04). LB densities in demented PD patients were significantly higher than those in non-demented PD patients, despite the shorter disease duration in the former. Moreover, plaque density in the temporal cortex and LB density in the cingulate cortex were significantly higher in the group with APOE4 than in that without the allele. There was no difference in tangle density between these two groups. These results suggest that APOE4 may influence the increase in the number of cortical LBs and amyloid plaques in PD. It is possible that when PD occurs in individuals with APOE4, concomitantly evolving cortical LB pathology in a proportion of cases results in limbic (transitional) or neocortical-type LB disease.

mtDNA polymorphisms in Japanese sporadic Alzheimer's disease.

We screened 92 Japanese patients with sporadic AD (clinically diagnosed: 72 cases; autopsy-confirmed: 20 cases) and 59 age-matched controls for mitochondrial polymorphisms previously reported to be associated with increased risk in Caucasian AD. The polymorphisms in tRNA(Gln) (nt. 4336), 16S rRNA (nt. 3196), and ND1 (nt. 3397) were not found in either in Japanese AD or age-matched controls. The frequencies of these polymorphisms in Japanese seems to be very rare if not absent, indicating that these three mutations are not likely to be genetic risk factors of Japanese AD. In the analysis of polymorphisms of 12S rRNA, however, we identified two novel mutations, an insertion of three cytosines and an A to G transition at nt. 856, which have not been described before. The insertion of three cytosines was observed in one of the 90 AD cases, but not in 59 normal controls. The A to G transition at nt. 856 was found in 2 of the 90 AD cases, but not in 59 normal controls. These results raise the possibility that the mutations in the 12S rRNA are genetic risk factors for AD in Japanese population.

Pick's disease: selective occurrence of apolipoprotein E-immunoreactive Pick bodies in the limbic system.

We carried out immunohistochemical examination of apolipoprotein E (apoE) in brains from two patients with Pick's disease. In these cases 1 and 2, the APOE genotypes were epsilon 3/4 and epsilon 3/3, respectively. In both cases, numerous argyrophilic globular intraneuronal inclusions, Pick bodies (PBs), were distributed widely throughout the brain, and immunohistochemically were occasionally positive for apoE. Interestingly, such apoE-immunoreactive PBs were virtually restricted to neurons in the limbic system; in the dentate gyrus, the proportion of apoE-immunoreactive PBs relative to the total number of argyrophilic PBs was 5.0% in case 1 and 2.7% in case 2, whereas in the frontal and temporal neocortices it was less than 0.1% in both cases. Diffuse cytoplasmic immunoreactivity for apoE was found in only a few limbic system neurons without PBs in both cases. In conclusion, it is considered that apoE may not be positively involved in the process of PB formation and that the preferential distribution of apoE-immunoreactive PBs in the limbic system may reflect the presence of certain regional factors associated with the synthesis or metabolism of apoE in this particular system.

Lack of association of very low density lipoprotein receptor gene polymorphism with Caucasian Alzheimer's disease.

To determine whether the association of the very low density lipoprotein receptor (VLDL-R) gene with Alzheimer's disease (AD), which has recently been identified in Japanese AD patients, is commonly observed in AD patients of other ethnic backgrounds, we have investigated the allele frequency of the polymorphic CGG repeat in the 5'-UTR of the VLDL-R gene using a data set of 84 Caucasian AD patients with 104 Caucasian controls. Although the allele frequency of the 8-repeat allele was slightly lower, and that of 9-repeat allele was slightly higher, in the Caucasian AD patients than in Caucasian controls, the differences were not statistically significant. Multiple logistic regression analysis using apolipoprotein E4 (APOE4) allele, 5, 8-, or 9-repeat allele of the VLDL-R gene, sex, and age at onset as the predictors revealed that only the APOE4 allele was significantly associated with AD in the data set of the Caucasian AD patients and controls.

Genetic association of the very low density lipoprotein (VLDL) receptor gene with sporadic Alzheimer's disease.

A specific isoform of apolipoprotein E has been associated with the accelerated rate of disease expression of sporadic Alzheimer's disease (AD) and late-onset familial AD (FAD). An earlier age at onset has also been demonstrated in familial AD patients with mutations in the amyloid precursor protein (APP) gene (APP717 and APP670/671)13 carrying the APOE epsilon-4 allele compared to those who do not, but not in familial AD patients with APP692 or 693 mutations, or in chromosome 14-linked familial AD patients. Hypothesizing that receptors for apoE-containing lipoproteins act as a potential risk factor for AD, we performed an association study using a polymorphic triplet (CGG) repeat in the gene for the VLDL receptor (VLDL-R), a receptor for apoE-containing lipoproteins. The frequency of the 5-repeat allele was significantly higher in all of the Japanese sporadic AD patients (P < 0.02) than in the Japanese controls. Moreover, the odds ratio was significantly increased in the AD patients homozygous for the 5-repeat allele (OR = 2.1, 95% CI = [1.1-4.2]). Multiple logistic regression analysis reveals that the relative risk conferred by the presence of two copies of the 5-repeat allele and at least one copy of the APOE epsilon-4 allele is 8.7 (95% CI = [2.9-25.8]). Our results suggest that the VLDL-R gene is a susceptibility gene for AD.

[MRI findings of posterior spinal artery syndrome--report of a case].

A 58-year-old woman presented with sudden onset of numbness and weakness of the lower limbs. She showed paraparesis associated with hyperreflexia and pathological reflexes in lower limbs. She showed decreased sensation of vibration and proprioception in lower limbs, as well as tingling sensation below Th11 level. Pinprick and thermal sensations were spared. Magnetic resonance imaging (MRI) of the spinal cord revealed a symmetric high signal intensity area at the posterior medial part of the spinal cord spanning Th9 to Th11 on T2-weighted and proton density images. On the basis of clinical findings as well as MRI findings, we made a diagnosis of posterior spinal artery syndrome. The MRI findings are considered to be highly useful for the diagnosis of PSAS.

Attainment and stability of the performance in differential low rate water reinforcement in rats.

The establishment and stability of the behavioral baseline for rats in relation to the schedule of differential reinforcement of low rate under water reinforcer (DRL 20 sec for water) were studied, with the following results: When the DRL value was gradually stepped up from 1 sec to 20 sec with the advance of the sessions from 1to 16, the establishment of the behavioral baseline was slower than when DRL 20 sec was applied from the start. The establishment of the baseline was clearly accelerated by the prolongation of the length of time for training in one session from 60 min to 120 min. The baseline remained highly stable without being affected by the intermittent administration (2-3 times a week) of methamphetamine and diazepam, each in doses from 0.06 to 1.0 mg/kg, and of caffeine and pentobarbital, each in doses from 1.2 to 20 mg/kg, or by the discontinuation of the test from 1 to 15 days. However, during the retraining period following the test discontinuation it was found that the baseline fluctuated for a long time due to the elimination of water deprivation. The baseline stability, once established, could be maintained through about 300 daily sessions, with only a slight dependence on the change in environmental conditions such as humidity, temperature, and the season.

Analytical study of acquisition on free-operant avoidance response for evaluation of psychotropic drugs in rats.

Systematic research was performed on the acquisition of free-operant (Sidman-type) avoidance response, which is widely used for the study of psychotropic drugs, with the following results: When the training session was fixed at 2 hours once daily, shock-shock (S-S) interval at 5 seconds, and response-shock (R-S) interval variable-20, 30 and 60 seconds, the acquisition speed of the response was almost constant independent of the R-S interval, about 6 sessions being always required. When the S-S and R-S intervals were constantly 5 and 30 seconds, respectively and the length of one session was varying-1, 2 and 4 hours, the behavioral baseline was established after about 6 sessions independently of the length of the session. Thus the cumulative time for the acquisition was shortest when one session was 1 hour long, and longest when it was 4 hours long. There was a linear relation with negative inclination between the logarithm of mean numbers of shock delivered per sessions and the number of sessions. In rapid and exact training of animals for the evaluation of drug effects, one session of an hour per day is adequate. In the evaluation of drug effects on the acquisition process, observation of the shift in logarithmic value of shocks delivered is recommended.

[Effects of penfluridol, a psychotropic agent, on operant behavior of rats].

Effects of penfluridol, a diphenylbutylpiperidine type psychotropic agent, on operant behavior were investigated and compared with those of chlorpromazine and haloperidol in rats trained on the following 5 schedules. Fixed ratio (FR 30) of food reinforcement and differential water reinforcement of low rate (DRL 20 sec) schedules were used for positively reinforced behaviors. Continuous (Sidman-type) and discriminated avoidance schedules were used for negatively reinforced behaviors. Conditioned suppression of response (CER) under FR 30 developed by stimulus presentation with electric shock was also applied. When 1 mg/kg of penfluridol was given orally, no change was observed in respondings of all the performances. At higher doses (2 approximately 8 mg/kg, p.o.), the respondings were inhibited in proportion to the dosage except in DRL performance, in which only correct response rate decreased at 8 mg/kg. These inhibitory effects were observed more apparently in the negatively reinforced behaviors than in the positively reinforced ones. Furthermore, a clear dose-effect relationship was obtained in the former. CER was not all attenuated by 2 approximately 8 mg/kg of penfluridol, thus a diazepam-like effect was not confirmed. These behavioral effects suggested that penfluridol has neuroleptic properties similar to those observed with chlorpromazine or haloperidol. However, in general, the inhibitory effects reached the maximum level approximately at 16 hr and lasted for 2 approximately 3 days after oral administration of the drug. Intensity of the effect of penfluridol was estimated to be about 1/8 approximately 1/10 that of haloperidol, according to the results obtained in the avoidance performances.