Journal of Neural Transmission - Parkinson's Disease and Dementia Section最新文献

Non-enzymatic glycosylation of proteins, also called Maillard reaction, which occurs at an accelerated rate in diabetes, can lead to the formation of advanced glycosylation endproducts (AGEs). Tenilsetam (CAS 997: (+/-)-3-(2-thienyl)-2-piperazinone), a cognition-enhancing drug successfully used for treatment of patients suffering from Alzheimer's disease, when included in the Maillard reaction apparently inhibits protein crosslinking by AGEs in vitro. According to the mechanism proposed, Tenilsetam acts via covalent attachment to glycated proteins, thus blocking the reactive sites for further polymerisation reactions. A beneficial effect of Tenilsetam in Alzheimer's disease could come from the interference with AGE-derived crosslinking of amyloid plaques and a decreased inflammatory response by diminished activation of phagocytosing microglia.

Monoamine metabolites and amino acid concentration in cerebrospinal fluid (CSF) of 33 untreated patients with parkinsonian syndrome, and 20 control patients without specific neurological symptoms have been compared with those obtained in cerebrospinal fluid of rats intrastriatally lesioned with 1-methyl-4-phenylpyridinium ion (MPP+) and sham operated animals. Homovanillic acid content was found to be significantly lower in patients with severe parkinsonism (motor score of UPDRS > 24), but not in patients with mild symptoms (motor score < or = 24). A correlation between the loss of striatal dopamine and the decrease in cerebrospinal homovanillic acid has been established in rats treated with MPP+. The extrapolation of these results to those obtained from human patients could be important in assessing the degree of striatal dopamine loss shown by humans with parkinsonian syndrome at the moment of clinical diagnosis. No significant differences were found between the other monoamine metabolites analyzed and free amino acid content in human and rat CSF.

Nitric oxide (NO) is thought to be involved in neurodegenerative processes. Concerning Parkinson's disease (PD) it remains to be elucidated, if NO contributes to pathological alterations in the striatum. The present study evaluates the post-mortem putamen of PD patients and control subjects for distribution patterns of NO-synthase containing neurons, using the NADPH-diaphorase technique. The ratio of positively stained neurons and the total number of cells (control: 1,120 +/- 69 per mm2, n = 5; PD: 575 +/- 164mm2, n = 5) shows striking differences between controls and PD patients. Our findings give reason to conclude that NADPH-diaphorase positive structures may have pathogenetic importance in degenerative processes in PD putamen.

ATP-sensitive K+ channels were examined in sections of the hippocampus from patients with Alzheimer's disease and age-matched control subjects by means of quantitative autoradiography. ATP-sensitive K+ channels were labelled with the sulfonylurea, [3H]-glibenclamide, which is a potent blocker of these channels. The density of cells in the subiculum and the activity of choline acetyltransferase were determined in the same hippocampal tissue samples. In the hippocampal formation of control subjects, the density of high affinity [3H]-glibenclamide binding sites ranged from 17.6 +/- 0.9 pmoles/g in the presubiculum to 11.6 +/- 0.6 pmoles/g in the parvo-pyramidal layer of the presubiculum. There was no difference between Alzheimer patients and controls in the level of high affinity [3H]-glibenclamide binding in any hippocampal region although there was a marked loss of subicular cells (reduced by 29% compared to controls) and a reduction in choline acetyltransferase activity (reduced by 60% compared to controls). The results suggest that ATP-sensitive K+ channels are associated with elements in the hippocampus which are preserved in Alzheimer's disease.

Before, we reported a higher frequency of circulating immune complexes (CIC) in the sera from institutionalized Alzheimer's disease (AD), multi-infarct dementia and Down's syndrome patients than from age-matched controls. In this study, we tested the presence of CIC in the sera from an extended series of hospitalized AD patients, AD patients living in the community, from age-associated memory impairment (AAMI) subjects as well as from nursing home and community controls. We used two methods to measure CIC, C1q binding Elisa (C1qB-Elisa) and conglutinin binding (KgB-Elisa). The AD patients showed the highest frequency of positive findings and differed from the controls in KgB (42% vs. 17%) (Chi-square, p = 0.01) and C1qB (30% vs. 11%) (p < 0.05). In severe AD, 14/19 patients were KgB positive and 11/19 were C1qB positive and differed from controls. The frequency of CIC for the patients with moderate or mild dementia, the AAMI subjects and controls was similar. In the multivariate linear regression analysis, high CIC values of the AD patients significantly associated with a long disease duration and a history of recurrent urinary infections but not with age, sex, hospitalization, or the Mini-Mental Status score. We conclude that AD patients with severe dementia frequently show CIC but those with mild or moderate disease do not. The CIC relate to a long disease duration and a history of recurrent urinary infections.

Exons 16 and 17 of the beta-amyloid precursor protein gene has been sequenced in individuals with the amyotropic lateral sclerosis/Parkinson's dementia complex of Guam to test the hypothesis that this disease is an allelic variant of Alzheimer's disease and to test whether sequence differences within beta-amyloid in this population contributes to the non-deposition of this peptide in the disorder. The sequence was normal.

A computer-aided method for the determination of colour fusion time (CFT) was developed. CFT indicates the acuity of the perception of monochromatic contours. CFT was determined in 36 patients with Parkinson's disease (PD) and compared with a group of 36 age- and sex-matched controls. Patients with PD generally had a shortened fusion time, especially for dark-green, light-blue and dark-red stimuli. The results give evidence to the hypothesis of a colour perception disorder in PD. The physiological and pathoanatomical basis of this phenomenon is unknown, but a functional deficit of cortical neurons may be a probable cause.

In addition to impaired dopaminergic neurotransmission a dysfunctional noradrenergic system has been demonstrated in Parkinson's disease. L-threo-3,4-dihydroxyphenylserine (DOPS), a synthetic precursor of noradrenaline (NA), appears to be effective in the treatment of some akinetic symptoms in parkinsonian patients. In the present study the possible effect of DOPS was studied in rats, in which catalepsy was induced with haloperidol as a model for parkinsonian akinesia. Intravenous infusion of NA (1.5 and 15 micrograms/kg) or DOPS (2 and 4 mg/kg) in male Wistar rats (240-290 g) significantly decreased catalepsy. The effect of DOPS was abolished by pretreatment with the peripheral decarboxylase inhibitor benserazide (2 mg/kg). Pretreatment with Ro 40-7592, a catechol-O-methyltransferase inhibitor, potentiated and prolonged the anticataleptic effect of DOPS. The findings suggest a peripheral site of NA mediated anticataleptic action. Therapy with DOPS may be successful only without a peripheral decarboxylase inhibitor. Moreover, the therapeutic effect of DOPS may be potentiated by COMT inhibition.

We studied the effect of phosphatidylserine (PdtSER) on oxygen metabolite toxicity in skin fibroblast cell lines from apparently normal subjects. Fibroblast damage was produced by the generation of oxygen metabolites during the enzymatic oxidation of acetaldehyde by xanthine-oxidase (Xo). In order to quantify cell damage, we measured lactate dehydrogenase (LDH) activity in culture medium and cell viability in fibroblast cultures, with and without preincubation for 4 days with PdtSER 13 microM, after Xo incubation. We found a significant increase of LDH activity in culture medium of cells without preincubation with PdtSER. No significant increase of LDH activity was observed in the same cell lines after preincubation with PdtSER.

The effect of tetrahydroaminoacridine (THA) on the cerebrospinal fluid (CSF) monoamine metabolites was studied in 22 patients with Alzheimer's disease in an open treatment trial. The CSF monoamine metabolites were assayed at baseline and after 4 weeks' active THA treatment with 100 mg/d. A statistically significant increase in the CSF homovanillic acid (HVA) and in 5-hydroxyindoleacetic acid (5-HIAA) content was found. The increase of the CSF 5-HIAA level correlated significantly with improvement in cognitive tests and in the Instrumental Activities of Daily Living Scale. We conclude that besides its anticholinesterase activity THA enhances also the monoaminergic neurotransmission in the brain and that the clinical improvement during THA treatment may be partly mediated through the monoaminergic system.