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Biomedical subjects

D Irving

Publications and source records attributed to D Irving.

At least 37 records · Page 2Linked to original sources

Cholinergic and dopaminergic activities in senile dementia of Lewy body type.

Analyses of brain tissue in a recently identified group of elderly demented patients suggest a neurochemical basis for some of the clinical features. Senile dementia of the Lewy body type (SDLT) can be distinguished from classical Alzheimer disease (AD) clinically by its acute presentation with confusion frequently accompanied by visual hallucinations, and neuropathologically by the presence of Lewy bodies and senile plaques (but not generally neurofibrillary tangles) in the cerebral cortex. Reductions in the cortical cholinergic enzyme choline acetyltransferase were more pronounced in individuals with (80%) compared to those without (50%) hallucinations and correlated strongly with mental test scores in the group as a whole. In the caudate nucleus, dopamine levels were related to the number of neurons in the substantia nigra, there being a 40-60% loss of both in SDLT--probably accounting for mild extrapyramidal features in some of these cases--compared with an 80% loss in Parkinson disease and no change in AD. The cholinergic correlates of mental impairment in SDLT together with the relative absence of cortical neurofibrillary tangles and evidence for postsynaptic cholinergic receptor compensation raise the question of whether this type of dementia may be more amenable to cholinotherapy than classical AD.

Aged↗

Simple measures of progress and outcome in the evaluation of mental health services.

There is a tautology regarding the use of progress and outcome measures. Such measures are easy to use in a reliable and valid fashion if the language of the measures is used as an integral part of (a) treatment planning and progress review, (b) clinical supervision, and (c) program management. The paper describes example guidelines and uses of measures in each of these functions. Also included are listings of scales with documented reliability and validity (by target population) and some sources for finding computer software for scoring some of the scales.

Evaluation Studies as Topic↗

Cortical neuropathological and neurochemical substrates of Alzheimer's and Parkinson's diseases.

Whilst the neuropathological correlates of Alzheimer type dementia--cortical neurofibrillary tangles and senile plaques--are well defined, the prevalence of these cortical abnormalities in Parkinson's disease and their relation to dementia is unclear. In a series of 46 consecutive cases of clinically and pathologically established Parkinson's disease the prevalence of mild Alzheimer-type pathology (exceeding the normal but not as extensive as in Alzheimer's disease) was increased 2 to 3 fold compared with an age-matched control group, although there was no obvious relation to the presence or severity of dementia. In a subgroup of Parkinsonian cases (both demented and non-demented), examined neurochemically, there were both similarities (decreased choline acetyltransferase, nicotinic and serotonergic S 1 receptor activities) and distinctions (increased muscarinic receptor binding--particularly to the "L" subtype, and normal serotonergic S 2, somatostatin, and D-aspartate binding together with normal levels of an endogenous nicotine binding inhibitor) compared with a group of cases with Alzheimer's disease. Amongst the various pathological and chemical indices examined, only presynaptic cholinergic markers (including the number of Meynert neurons) and S 1 receptor binding were related to dementia in Parkinson's disease. It is suggested that whilst coincidental classical Alzheimer's disease is infrequent in Parkinson's disease (5% in the present series) Alzheimer's disease itself is distinguished from Parkinson's disease by the formation of numerous neocortical neurofibrillary tangles and a reduction in glutamate uptake, serotonergic S 2 receptors and possibly in endogenous nicotine binding inhibitor.

Adult↗

A natural history of behavioral health program evaluation in Arizona.

This article examines the history of behavioral health program evaluation efforts in the state of Arizona during the years 1974-1982. Program Evaluation in Arizona has been carried out in an environment where planning, monitoring, contracting, appropriations, and evaluation have been inter-related--sometimes loosely, sometimes closely. Here we trace the year-by-year evolution of the evaluation system and its connections with the other parts of the environment. This history illustrates the gradual development of an evaluation system in an organizational context, including the sidetracks and setbacks .

Arizona↗

Pathological changes in the nucleus of Meynert in Alzheimer's and Parkinson's diseases.

Combined neuropathological and neurochemical assessment of the nucleus of Meynert in senile dementia of Alzheimer type (SDAT) have demonstrated that the cholinergic biochemical activity, choline acetyltransferase, is more extensively reduced in the nucleus (over 90%) than the loss of putative cholinergic perikarya (35%). Acetylcholinesterase histochemical activity was however substantially retained in individual neurones in the nucleus although virtually absent from the neocortex in SDAT. These abnormalities are consistent with a primary degeneration of cholinergic axons projecting to the cortex and secondary loss of perikarya from the subcortical nucleus. In contrast, preliminary observations on cases of Parkinson's disease suggest that the neuronal loss from the nucleus of Meynert may be greater in this disease than in SDAT, and previous studies have not consistently demonstrated a reduction in cortical choline acetyltransferase activities in Parkinson's disease. These observations, together with major differences in the neuropathology of the nucleus in SDAT and Parkinson's disease (neurofibrillary tangle and Lewy body formation, respectively) suggest that the involvement of the cholinergic system may differ in the two disease processes.

Acetylcholinesterase↗

Extensive loss of choline acetyltransferase activity is not reflected by neuronal loss in the nucleus of Meynert in Alzheimer's disease.

Choline acetyltransferase activity in discrete tissue punches from the nucleus of Meynert and in tissue from the temporal cortex was reduced by at least 90% and 75%, respectively, in 5 out of 6 elderly cases of Alzheimer's disease compared with 5 normal cases. In contrast, estimates of neurone density in these same cases revealed that there was only, on average, a 33% neurone loss in the nucleus of Meynert in Alzheimer's disease. These observations suggest that a key pathological change in Alzheimer's disease may be the 'down regulation' of transmitter-specific enzyme production in cholinergic neurones, and that neurone loss itself may be a secondary feature of the disease.

Aged↗

Cell loss in the locus coeruleus in senile dementia of Alzheimer type.

Sample counts of the pigmented cells of the locus coeruleus (LC) were performed in 10 middle-aged and 15 old people considered to be intellectually well preserved and in 15 cases of senile dementia of Alzheimer type (SDAT). Evidence of a gradual loss of neurons from early middle to old age was found in the control group. In the cases of SDAT 7 counts were within the lower range for the controls but 8 had fewer neurons than any control recorded and the mean count for all the SDAT cases was significantly less than that of the older controls. Some evidence exists that the more severe cases of SDAT in terms of neocortical plaque formation have the greatest loss of LC neurons.

Adult↗

Relief of bileduct obstruction by the percutaneous transhepatic insertion of an endoprosthesis.

Benign and malignant biliary strictures can be treated by the percutaneous transhepatic insertion of an endoprosthesis. We report the use of this technique in 44 patients, with a detailed description of the procedure. Insertion was successful in 41, three of whom later had elective surgery, and one, emergency laparotomy for biliary peritonitis. This patient died post-operatively. Cholestasis was relieved in 31 of the remaining 37 patients. Complications occurred in four. Twelve patients, all with malignant disease, died within 30 days of the procedure. The percutaneous insertion of a biliary endoprosthesis is a valuable alternative to surgery in selected patients. Complications can occur, and the prognosis depends on the nature of the underlying disease.

Adult↗

Planning inaction?

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Regional Health Planning↗