Dementia (Basel, Switzerland)最新文献

Preliminary to a multicenter trial, an open-label study was conducted of prednisone treatment in Alzheimer's disease. Prednisone was given at an initial dose of 10 mg (part 1) or 20 mg (part 2) and tapered over 7 weeks. There were no serious adverse events attributed to the medication, and there were no significant changes in either mean cognitive or behavioral assessment scores with treatment during either part. Serum levels of the acute phase proteins alpha-1-antichymotrypsin and C-reactive protein did not change significantly during part 1, but were suppressed by the higher dose given in part 2. Thus, a prednisone regimen with an initial dose of 20 mg is tolerable and results in suppression of the acute phase response in Alzheimer's disease.

It has been reported that many tau sites in neurofibrillary tangles (NFT) are abnormally phosphorylated. We investigated the phosphorylation of tau in the hippocampus of nondemented patients and Alzheimer's disease patients by immunostaining with five site-specific antibodies against phosphorylated tau. In the pretangle stage, tau in neuropil threads was phosphorylated at serines 199, 202 and 409, numbered according to the longest human tau isoform, whereas tau in some neuronal soma was phosphorylated at serines 199, 202, 409 and 422. Tau at the stage of NFT was phosphorylated at serine 396 and threonine 231 in addition to serines 199, 202, 409 and 422. In the advanced stage, tau in ghost tangles was phosphorylated mainly at serine 396. These results suggest that the phosphorylation of each site in tau differs among the maturing stages of neurofibrillary change and that abnormal phosphorylation of tau in the neuronal soma occurs at 199, 202, 409 and 422 earlier than at threonine 231 and serine 396.

Xanomeline, a substituted TZTP, is a new M1 selective muscarinic agonist in clinical trials for Alzheimer's disease. The brain uptake of [11C]xanomeline and the analog [11C]butylthio-TZTP was examined by positron emission tomography (PET). Radioactivity accumulated most markedly in the neocortex and the striatum. Pharmacological characterization in vitro and in cynomolgus monkeys in vivo by PET indicated specific [11C]butylthio-TZTP binding to muscarinic receptors and to sigma-1 recognition sites. More than 5% of the radioactivity was in the human brain 5 min after i.v. injection of [11C]xamomeline or [11C]butylthio-TZTP. This high brain uptake may be clinically advantageous in the sense that substituted TZTP may induce central muscarinic agonist effects at a dose level for which there is a low risk of peripheral side-effects.

In clinical practice, Alzheimer's disease (AD), multi-infarct Dementia (MID) and depression are often difficult to differentiate and may coexist. This study reports the findings of CT and MRI focused on hippocampal atrophy (HA). Quantitative volumetric MRI measurements of the hippocampus showed a reduced volume in AD patients compared to normal controls with no overlap. CT studies reported a significant widening of the hippocampal fissure in AD patients. Because volumetric measurements are not available for routine examinations, so far we are required to use the finding of hippocampal lucency in CT and dilatation of the directly visible hippocampal fissure in coronal MRI scans as criteria for HA. These findings were visually classified on a 4-point scale by 2 neuroradiologists, who had no knowledge of the clinical diagnosis. The examinations of 80 patients (42 with AD, 22 with major depression, 3 with MID, 6 classified as age-associated memory impairment (AAMI) and 8 'normals' with only subjective memory impairment) showed that the HA strongly supports the diagnosis of AD, by correctly identifying 95% of the AD patients and 47.8% of the patients without AD. These results suggest that CT and MRI examinations of the hippocampus are capable of demonstrating HA in clinical practice, which is strongly correlated with the diagnosis of AD.

Two contrasting multivariate statistical methods, viz., principal components analysis (PCA) and cluster analysis were applied to the study of neuropathological variations between cases of Alzheimer's disease (AD). To compare the two methods, 78 cases of AD were analyzed, each characterised by measurements of 47 neuropathological variables. Both methods of analysis revealed significant variations between AD cases. These variations were related primarily to differences in the distribution and abundance of senile plaques (SP) and neurofibrillary tangles (NFT) in the brain. Cluster analysis classified the majority of AD cases into five groups which could represent subtypes of AD. However, PCA suggested that variation between cases was more continuous with no distinct subtypes. Hence, PCA may be a more appropriate method than cluster analysis in the study of neuropathological variations between AD cases.

NMDA receptor density as measured by the specific binding of [3H]MK 801 was significantly decreased (about 20%) in the frontal but not in the parietal cortex of postmortem brain samples of Alzheimer's disease (AD) patients (n = 21), when compared with control brains (n = 20). Membrane fluidity was not altered in the frontal cortex samples, but was slightly reduced in the parietal cortex samples of the AD patients. Since AD-specific histopathological changes (densities of senile plaques and neurofibrillary tangles) were about similar in both areas, it is concluded that the reductions of NMDA receptor densities in the frontal cortex is independent of AD-specific histopathological changes and of changes of membrane fluidity.

Cognitive deficits are the most important symptoms in the diagnosis of dementia. Changes in noncognitive behavioural areas often go unrecognised at examination or are considered insignificant. These abnormalities, however, contribute most to the caregiver's burden, interfere with the individual well-being of the patient, and are predictors of early institutionalization. Psychotherapeutic interventions in dementia complete the treatment effects achieved by psychopharmacology, cognitive enhancers, and cognitive training of target functions. Psychotherapy in dementia should be based on an interacting form of therapy, i.e. a contingency management in the natural environments of the dementia sufferer where the primary caregiver, as a mediator, takes over the main therapeutic tasks.

The most important new development during recent years in the field of degenerative dementia concerns synaptic pathology. So far it has been investigated in some regions and some cortical laminae in Alzheimer's disease (AD). The present communication is a more comprehensive study of all laminae in four different regions, the prefrontal, parietal, inferior temporal and posterior cingulate cortex. Against the background of normal aging, AD was compared with another degenerative disorder, frontal lobe degeneration of non-Alzheimer type (FLD). The synapse density was measured using synaptophysin as a marker. Astrocytes were also counted in the molecular layer. In normals, the cortex showed successively lower synaptic density from layer I to layer VI and relatively lowest density in the prefrontal cortex and a general decline with increasing age. A 46-49% decrease in synaptic density was found in all laminae in all regions of AD brains, a finding different from that in FLD. The number of astrocytes increased significantly in the prefrontal cortex both in AD and FLD but parietally only in AD. These results contribute to the understanding of normal synaptic organization of cortex, demonstrate the laminar and regional distribution of synaptic loss in AD and underscore the difference between AD and FLD. The gliosis appears to be secondary to the neurodegenerative changes. Synaptic loss is likely to be a common pathogenetic feature of neurodegenerative disorders and a likely cause of clinical symptoms and regional metabolic decrements in dementia.

Individual differences in the development of neurofibrillary changes were examined in eight cortical regions in the brains of 43 subjects with Down syndrome (DS; age range, 15-69 years) using sections stained with monoclonal antibodies (mAb) tau-1 and 3-39. Neurofibrillary pathology was found in 4 cases below 36 years of age and in all 20 cases above that age. In the 24 positive cases, numerical density of pretangles stained with tau-1 and 3-39, respectively, was 6.1/mm2 and 0/mm2; early tangles, 5.0/mm2 and 5.3/mm2; mature tangles, 4.0/mm2 and 5.0/mm2 (p < 0.01); and end-stage tangles, 0.04/mm2 and 2.5/mm2 (p < 0.001). Numerical density of pretangles stained with mAb tau-1 and tangles and plaques stained with mAb 3-39 correlates weakly with age (r = 0.43; p< 0.02), and together with the wide range of numerical densities suggested heterogeneity of the population examined. Cluster analysis based on two variables - i.e., numerical density of pretangles stained with mAb tau-1 and neurofibrillary tangles (NFTs) and plaques stained with mAB 3-39, distinguished three groups of subjects with severe, moderate and weak changes. The severely affected group of 5 subject (21%) had an average 54.6/mm2 of neurons and 13.9/mm/ plaques with neurofibrillary changes, whereas the moderately affected group (6 subjects; 25%) showed a significantly lower numerical density of neurons and plaques with neurofibrillary changes (25.7/mm2 and 8.1/mm2, respectively) as compared with the most affected group. Most of the subjects (13; 54%) belong to the third group with only 2.2/mm2 of neurons and 1.4/mm2 plaques with neurofibrillary pathology. Comparison of these three groups of Down syndrome subjects representing high, moderate, and low susceptibility to neurofibrillary changes with the general population suggests that the risk of Alzheimer disease is similar but the onset of pathological changes is earlier in DS.