ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SummaryPositron emission tomography (PET) with18F-2-fluoro-2-deoxy-D-glucose (FDG) demonstrates a typical pattern of impairment of regional metabolic rates of glucose (rCMRGlu) in most patients with a clinical diagnosis of probable Alzheimer's disease (AD): reduction of rCMRGlu in temporo-parietal association cortex, more variably also in prefontal cortex, but relative preservation of primary visual and sensorimotor cortex, striatum, and cerebellum. Apart from early stages, both hemispheres are affected, but pronounced asymmetries may be present. With the exception of Parkinson's disease with dementia, the complete pattern is rarely seen in other dementing conditions, which usually lead to more global, frontal or multifocal metabolic impairment. Severity of dementia is mainly correlated with temporo-parietal rCMRGlu reduction, probably irrespective of the cause of dementia, and the neuropsychological profile is related to the asymmetry of metabolic alterations. Procedures are available for assessment of the typical pattern that yield comparable results in different laboratories, and have a high accuracy for discrimination between normals and probable AD. Diagnostic accuracy is better for presenile than for senile dementia of Alzheimer type, and for moderate to severe cases than for mild dementia. A definitive judgement of the diagnostic value of FDG PET in AD is hindered by the lack of sufficient data with diagnosis confirmed at autopsy.

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SummaryThere is increasing evidence for genetic heterogeneity in Alzheimer disease. A longitudinal clinical and imaging study had been established in order to determine whether specific phenotypic profiles are present in aetiologically distinct familial Alzheimer disease (FAD) pedigrees. [18F]fluorodeoxyglucose positron emission tomography has been used in conjunction with statistical parametric mapping to determine the relative distribution of hypometabolism. A parietotemporal deficit has been observed in individuals from both amyloid precursor protein mutation and chromosome 14 linked FAD families. Preliminary data from asymptomatic individuals at risk of FAD shows similar, although a less extensive pattern of deficit.

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SummaryA compartment model has been developed and validated for the kinetic analysis of (S)(-)11C-nicotine binding in the brain including a compensation for the influence of regional cerebral blood flow (rCBF). The model was applied to eight patients with Alzheimer disease (AD) and three age-matched healthy volunteers who received intravenous injections of (S)(-)11C-nicotine and11C-butanol. The uptake and time course of radioactivity in different brain regions were assessed by positron emission tomography (PET). The rate constantk*was formulated by dividing the K2rate constant for11C-nicotine with the K, rate constant for11C-butanol and thereby minimizing the influence of CBF on the quantitated binding of11C-nicotine. The rate constant k2*for11C-nicotine giving a quantitative measure of binding in the brain tissue was significantly higher in the temporal and frontal cortices as well as in the hippocampus of AD brains as compared with controls, indicating deficits in specific nicotinic binding in these brain areas of AD patients. A significant and negative correlation was obtained between cognitive function (Mini-Mental State Examination) and k2*of11C-nicotine in the temporal and frontal cortices as well as in the hippocampus. The described kinetic model allowed in vivo quantification of nicotinic receptor binding in brain, which will be of importance in the future for evaluation of diagnosis, progress of disease, as well as the therapeutic effects in the treatment of AD.

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SummaryLocal metabolites have long been considered to play an important physiological role in regulating regional cerebral blood flow (rCBF). However, the evidence reviewed here emphasizes that the regulation of (rCBF) by central cholinergic nerves is independent of regional metabolism. Activation of the intracranial cholinergic fibers originating in the nucleus basalis of Meynert (NBM) and septal complex releases acetyl-choline in the cortex and hippocampus, which results in vasodilation and an increase in rCBF in the cortex and hippocampus. Such intracranial cholinergic vasodilative nerve fibers do not belong to the autonomie nervous system according to the traditional definition by Langley, but interestingly, these fibers behave in the brain similarly to the action of autonomie nerves in peripheral organs. The NBM could be transiently stimulated to increase rCBF by nonpharmacological methods. For example, cutaneous sensory stimulation activates the cholinergic nerves originating from the NBM to enhance rCBF. The increase in rCBF at the diffuse cortices during walking appears to include an excitation of this NBM-originating cholinergic vasodilation system. Other various inputs to the NBM may have a similar effect to enhance rCBF via activation of that cholinergic system, provided the stimulation is delivered properly. Thus the combination of pharmacological and non-pharmacological techniques may provide a balance in our attempts to improve cholinergic replacement therapy.

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SummaryMagnetic resonance head scans of 94 patients with probable Alzheimer disease (AD) and 45 patients with possible AD were examined prospectively to determine the prevalence and significance of rarefied cerebral white matter (leukoaraiosis) in patients with AD. Only 8.7% of patients with probable AD and 11.1% of patients with possible AD exhibited large confluent areas of subcortical leukoaraiosis. The remaining patients had variable degrees of leukoaraiosis surrounding the lateral ventricles. The magnitude of leukoaraiosis correlated with the patient's age but not with the Hachinski Ischemic and Mini Mental Status scores. Postmortem studies of two Alzheimer patients showed that their large confluent areas of subcortical leukoaraiosis consisted of rarefied white matter, gliosis, and arteriosclerotic small arteries. Eight additional Alzheimer patients who underwent autopsy had similar but less pronounced white matter changes limited to the periventricular regions of the cerebral hemispheres. Large confluent areas of rarefied subcortical white matter occur in a small minority of Alzheimer patients and are probably not caused by AD.

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SummaryThe specificity of BR88, a polyclonal antibody we raised against amino acids 1–12 of β/A4 (β-amyloid protein), has been reexamined in view of a claim made that it cross-reacts with τ-protein, probably the sole component of the paired helical filaments of Alzheimer disease. We have used enzyme-linked immunosorbent assays, immunoblots, and immunohistochemistry, together with appropriate controls, to show that BR88 does not cross-react with τ. This contradicts the claim in question and confirms our previous findings in which BR88 was used to show that some tangle-bearing cells displayed the N-terminus of β/A4 on their surfaces. The conclusions formed in that earlier work therefore remain intact.

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

SummaryThis study evaluated Alzheimer disease (AD) patients' awareness of impairment in several domains, including cognitive, psychiatric, and behavioral functioning. Ratings made by 13 patients with moderate to moderately severe probable AD were compared with ratings made by their relatives using the Cognitive Behavior Rating Scales (Williams et al., 1985; Williams, 1987). Unawareness was defined as the discrepancy between informant and patient ratings. Informants consistently rated patients' impairment as more severe than the patients rated themselves. However, the discrepancy between the ratings was statistically significant only for Language Disorder, Higher Cognitive Deficits, Memory Disorder, Dementia, and Apraxia, and not for Agitation, Need for Routine, Depression, and Disorientation scales. Unawareness was not related to severity of memory impairment, as measured by the Rivermead Behavioural Memory Test (Wilson et al., 1985). The results of this small, preliminary study of relatively severely impaired AD patients suggest that awareness of psychiatric and behavioral problems may be relatively preserved compared to awareness of cognitive problems. These findings should be replicated with a larger sample with a broader range of severity.

ISSN:0893-0341    

出版商:OVID    

年代:1995

数据来源: OVID