Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.107 (DAT)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apraxia was tested in 12 DAT patients with mild to moderate dementia using two assessment procedures: conceptual tasks requiring object use and pantomime knowledge, and tasks based on the imitation of meaningless oral and hand movements. Both object use and pantomime performance were markedly impaired in the DAT group; imitation of hand postures, hand movements and multiple oral movements was also defective while single oral movements could be well imitated. Error analysis revealed several underlying deficits: on conceptual tasks, deficits in object and action knowledge and poor action planning were frequent, whereas impaired recall and coordination of spatial and temporal movement features were found on imitation tasks. A correlation analysis between both types of apraxia showed low and nonsignificant results. These and previous observations suggest that motor control is organized by two functionally separate systems: a conceptual system for purposeful and symbolic motor acts, and a system controlling sensorimotor and spatiotemporal movement features. Both systems may be subject to early damage in Alzheimer's disease.
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PMID:Two forms of apraxia in Alzheimer's disease. 812 45

A study was performed to assess the occurrence of senile dementia in institutions for the elderly. In a total of 747 cases examined in 1986 we diagnosed 316 (42.3%) to be suffering from dementia. The patients were subdivided by etiology into 4 categories: Vascular type (VD) 51.6%, Alzheimer type (DAT) 21.8%, Mixed type 9.2% and others 17.4%. Subsequently 124 of these demented patients died and autopsies were performed on 104 cases by 1990. Final clinical diagnoses were made and correction of initial diagnoses was necessary in 15 cases. The agreement rate between final clinical and pathological diagnoses was 79.8% for all 104 cases where data was available. For individual categories treated separately, the rates were VD 83.3%, DAT 89.3%, Mixed 64.7% and others 63.6%.
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PMID:[Senile dementia in institutions for the elderly--agreement rate between clinical and pathological diagnoses]. 823 44

Brain glucose utilization and ATP formation were found to be reduced to 54% and 81%, respectively, of control values in incipient sporadic dementia of Alzheimer type, causing reduced availability of the glucose-derived neurotransmitter acetylcholine. With respect to energy shortage, impacts on energy-dependent processes such as synaptic transmission, ion homeostasis, protein processing and degradation, extracellular transmission, and extracellular phosphorylation may be expected. Normal processing of the amyloid precursor protein was demonstrated to occur via a muscarinergic acetylcholine M1 and M3 receptor-mediated signal transduction pathway. Since both the muscarinergic acetylcholine receptors on pyramidal neurons and G proteins were found to be unaltered in DAT, the possibility is discussed that the diminution of glucose utilization and the energy shortage in DAT brain may contribute considerably to abnormal amyloid precursor protein processing and thus to secondary amyloid formation.
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PMID:Abnormalities in brain glucose utilization and its impact on cellular and molecular mechanisms in sporadic dementia of Alzheimer type. 823 17

The shape and thickness of the third ventricles were studied with magnetic resonance imaging in 46 patients under evaluation for memory impairment. We compared this population with 23 subjects imaged for other reasons. The study group consisted of patients with diagnoses of probable dementia of the Alzheimer's type (DAT; 35.6%), multi-infarct dementia (MID; 22.2%), depression (8.9%), alcoholic dementia (6.7%), other dementias (OD; 13.2%) and no dementia (6.7%). Within the study group, there were no significant differences across diagnostic categories for duration of symptoms or level of education. Patients with DAT were, however, more impaired than others (Mini-Mental State Examination scores: DAT 14.6 [+/- 8.2] versus MID 17.4 [+/- 6.2] versus OD 21.2 [+/- 6.4]). Demented subjects were more likely than nondemented individuals to have a convex third ventricle and greater wall separation. The results suggest that the shape of the third ventricle may correlate with dementia. Possibly, the dorsal medial nucleus of the thalamus is involved in the dementia.
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PMID:Convex third ventricle: a possible sign for dementia using MRI. 825 Oct 50

The present study on brain electrical activity in healthy subjects (n = 35) and patients suffering from dementia of the Alzheimer type (DAT; n = 35) used Fast Fourier Transformation-dipole approximation to quantify differences between the two groups. DAT patients showed a shift of alpha and beta activity toward frontal brain regions. The amount of this shift correlated with the degree of dementia. The relative distribution of magnitude of activity between the frequency bands differed between DAT patients and control subjects. DAT patients had higher magnitudes in the slow frequency range, correlating with the severity of dementia, and lower ones in the alpha and beta range compared with findings in age-matched control subjects.
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PMID:Dementia of the Alzheimer type: effects on the spontaneous EEG described by dipole sources. 827 51

Thirty-five patients with organic dementia were investigated with multichannel FFT analysis of EEG. In 21 of them, somatosensory-evoked potentials (SEPs) with stimulation of the median nerves were also recorded. Based on clinical and psychometric data and regional cerebral blood flow measurements, the patients were subdivided into Alzheimer-type dementia (DAT) of moderate (n = 10) and severe (n = 11) degree, multi-infarct dementia (MID) (n = 7), and frontotemporal degeneration (FTD) (n = 7). The FTD patients showed mild EEG abnormality and the MID patients showed increases of low frequency activity in combination with a well-preserved posterior dominant activity. The DAT patients showed the most pronounced abnormalities with deterioration of the posterior activity combined with a large increase of low frequency activity. The SEPs of the DAT group showed an amplitude enhancement of the parietal response components. The FTD group showed only a moderate delay of the precentral N30 component. The MID group showed individually varying abnormalities, including a delay of the primary cortical response. It is concluded that the different distributions of pathology in the different organic dementia disorders are reflected in the quantified EEG and SEPs as studied with multichannel technique.
Dementia
PMID:Multichannel EEG frequency analysis and somatosensory-evoked potentials in patients with different types of organic dementia. 835 5

1. Early-onset dementia of Alzheimer type (EODAT; AD) and late-onset dementia of Alzheimer type (LODAT; SDAT) are heterogenous in origin. 2. A common superordinate pathobiochemical principle in the etiopathogenesis of both types of dementia is neuronal energy failure with subsequent abnormalities in cellular Ca2+ homeostasis and glucose-related amino acid metabolism. 3. These metabolic abnormalities are assumed to occur first at axodendritic terminals of the acetylcholinergic-glutamatergic circuit and to cause morphological damage at synaptic sites. 4. Metabolic stress and structural damage at synaptic sites may induce enhanced formation of APP and its cleavage product amyloid. 5. Energy-metabolism related abnormalities along with functional and structural changes at synaptic sites of the acetylcholinergic-glutamatergic circuit may precede the formation of amyloid in DAT brain.
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PMID:Intermediary metabolism disturbance in AD/SDAT and its relation to molecular events. 843 Feb 15

CT images of leuko-araiosis in brain slices were quantified according to volumes of reduced Hounsfield units in frontal periventricular white matter in groups of elderly patients with multi-infarct dementia (MID, n = 23) and dementia of the Alzheimer type (DAT, n = 16). Volumes of leuko-araiosis, estimates of atrophic cerebral tissue, and local cerebral perfusion utilising inhalation of xenon gas as the indicator were correlated on the same CT slices. Ratios of frontal leuko-araiosis to total brain tissue volume were similar for patients with MID and DAT (mean 5.7 (SD 2.1)% v 6.5 (3.2%)), and both were significantly greater than ratios in elderly normal volunteers (3.1(1.3)%, 0 < 0.001). Cerebral atrophy (measured as the ratio of volumes of cerebrospinal fluid to total brain area) for DAT patients was 17.0 (6.7)%, which was greater than for MID patients (12.5 (5.4)%; p < 0.05) and both types of patients showed more cerebral atrophy than did age matched, elderly normal subjects. Cerebral perfusion was decreased in all regions measured in patients with MID and DAT compared with elderly normal subjects. Multi variate regression analyses correlated frontal leuko-araiosis with reductions of local cerebral blood flow in subcortical grey matter (p < 0.025) in patients with vascular dementia but not in those with DAT. These quantitative measures implicate decreased perfusion due to atherosclerosis in territories supplied by the deep penetrating cerebral arteries in the pathogenesis of leuko-araiosis in patients with vascular dementia, but suggest a different pathogenesis for leuko-araiosis in Alzheimer's disease.
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PMID:Correlations of leuko-araiosis with cerebral atrophy and perfusion in elderly normal subjects and demented patients. 843 7

The clinical diagnosis of organic brain syndromes (especially of primary degenerative dementia) in their early stages is uncertain or only tentative. We used a set of relatively simple tests to support the hypothesis that the disturbance of several operational brain functions precedes memory decline in primary degenerative dementia. Twenty-one patients with early stage, presenile onset of DAT, 14 patients with cardiovascular disease (CVD) and a questionable dementia, an age-matched control group (EC, n = 15), and a younger control group (YC, n = 16) were examined in the following tests: labyrinth learning test, tactile and visual pattern recognition, different reaction time tasks, eye-tracking, finger-tapping, alpha-EEG-blockade, photic driving, flicker fusion frequency, and interaction tasks. The test demonstrated that the patients performed more slowly for all tasks than did control subjects. The CVD patients performed better than the DAT group, but they were also significantly worse in the tests compared with healthy elder subjects. This test battery was found purposeful for early diagnosis of both primary degenerative and other forms of dementia, and may also be helpful to exclude other forms of organic brain syndromes.
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PMID:[Test battery for objective assessment and differential diagnosis in the early stage of suspected development of presenile dementia of the Alzheimer type]. 849

Older drivers with dementia are involved in more crashes than healthy older drivers. Some investigators, therefore, have proposed that a diagnosis of dementia (DAT or other type) should lead to the automatic revocation of a driver's license. In the authors' view, however, renewal of license should be based on criteria related to driving competence rather than solely on chronologic age or a medical diagnosis. Unfortunately, current competency testing procedures do not assess the attentional factors discussed herewith that have been found to be important for safe driving. As the studies reviewed in this article reveal, there is good evidence that a skill test that predicts crash involvement in older drivers should incorporate attentional measures, in particular tests of attentional shifting based on dichotic listening and related tests. There is also evidence that attention-shifting measures are diagnostic of attention impairment in the early stages of Alzheimer-type dementia. Further research is needed to determine whether other attentional skills, such as sustained and divided attention, also need to be assessed. Additional work also is needed to refine attention tests for ease of use in the clinical setting. Lastly, although these attention measures account for only some of the variance contributing to crash involvement, they may allow for better predictive capability when combined with measures of other skills involved in driving. Driver training programs can complement driver testing procedures in serving the dual requirement for reducing crash risk among drivers with dementia while continuing to be responsive to their mobility needs. Information on the role of attention and other cognitive skills in safe driving should be made available, so that drivers (or their family members) who think they may have declining skills can seek further evaluation. Organizations such as automobile associations and retired persons groups can provide self-assessment inventories for completion by older drivers or referral for medical and neuropsychological evaluation. Finally, training techniques for improving attentional skills in drivers with DAT need to be developed and tested.
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PMID:Attention and driving. Assessment in elderly individuals with dementia. 850 86


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