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Biomedical subjects

D Neary

Publications and source records attributed to D Neary.

At least 109 records · Page 6Linked to original sources
PubMed1981

Renaut body distribution at sites of human peripheral nerve entrapment.

In an autopsy study of the pathology of chronic subclinical nerve entrapment Renaut bodies showed a strong predilection for sites of nerve entrapment. They were present at these sites in 43 of 74 peripheral nerves but in none of the control sections of the same nerves. Renaut bodies were most frequently encountered in the median nerve at the wrist and in the lateral femoral cutaneous nerve at the inguinal ligament but were rarely seen in sections of the common peroneal nerve at the neck of the fibula. Renaut bodies were closely associated with thickened subperineurial capillaries, and, in successive transverse sections, they terminated in a fibrous mass of these thickened vessels. In several nerves Renaut bodies showed a similar orientation within adjacent fascicles, suggesting that mechanical factors were related to their pathogenesis; despite this finding there was no relationship between their numbers at entrapment sites and the presence of pathological changes in myelinated nerve fibres at the same level. These findings suggest that while mechanical factors are important in the pathogenesis of Renaut bodies there is no evidence to support the theory that these structures protect nerve fibres from mechanical stress.

Humans↗
PubMed1981

Alterations in protein synthetic capability of nerve cells in Alzheimer's disease.

Cytoplasmic RNA content, nuclear and nucleolar volume are all significantly reduced in nerve cells of the temporal cortex in cases of Alzheimer's disease, examined both at diagnostic craniotomy and post mortem, when compared with non=demented control cases of similar age. On average, at necropsy, all three parameters are equally reduced by about 40-50%, but in biopsy cases, nuclear volume is decreased by the greatest amount (43%), followed by nucleolar volume is decreased by the greatest amount (43%), followed by nucleolar volume (36%), and cytoplasmic RNA (26%). These findings indicate that a change in protein synthesis occurs daily in the course of Alzheimer's disease which may result from a primary alteration within the nuclear apparatus.

Adult↗
PubMed1980

Glucose metabolism and acetylcholine synthesis in relation to neuronal activity in Alzheimer's disease.

The metabolism of (U--14C) glucose and its incorporation into acetylcholine were determined in vitro in fresh cortical biopsy samples from patients with Alzheimer's disease and controls. Synthesis of 14C acetylcholine was significantly reduced (60% and 67% reduction under stimulated and resting conditions, respectively) without significant changes in the overall metabolism of glucose (as measured by 14CO2 production). Acetylcholine synthesis was directly related to the activity of choline acetyltransferase. The changes in cholinergic markers reflected the severity of psychological defects. Acetylcholine synthesis was not reduced in biopsy samples from patients suffering from presenile dementia with no histological evidence of Alzheimer's disease.

Acetylcholine↗
PubMed1980

Amnesia is not caused by cognitive slowness.

It has been suggested that the memory disorder in human organic amnesia might be caused by the slow processing of information. Such slowness might be differentially greater for semantic tasks, and/or for tasks requiring the extraction of multiple features of stimuli, or it might simply be a non-specific slowing. These possibilities were tested in a group of alcoholic amnesics and matched normal controls by presenting subjects with a series of words and requiring them to identify one specified word or one of two specified words, or membership of a specified category or one of two specified categories. Although amnesics' reaction times were slightly slower than controls' the effect was insignificant, and there was no hint of differential slowing in the semantic or multiple processing tasks. It was concluded from these results and a consideration of the reaction time literature that cognitive slowness is unrelated to the main cause of amnesia.

Alcohol Amnestic Disorder↗
PubMed1977

The thoracic outlet syndrome.

Thirty-one patients with thoracic outlet syndrome have been studied in detail in the neurological and vascular clinics at this hospital. The patients were classified on the basis of their presenting symptoms into four groups--predominantly vascular, neurological, combined vascular and neurological, and pain and paraesthesiae alone. The majority of patients had radiological abnormalities and all had structural lesions in the superior thoracic aperture seen at operation. All operations were carried out through a standard supraclavicular approach, enabling the compressive structures to be visualized. This would not have been the case had the commoner trans-axillary approach for first rib resection been followed and in fact none of the operations included removal of the first rib. The results of operation were evident in our patients with a marked relief in their vascular symptoms, their pain and paraesthesiae and a slight but definite improvement in muscle bulk and power.

Adolescent↗
PubMed1975

Sub-clinical entrapment neuropathy in man.

Twelve median and 12 ulnar nerves were obtained at routine autopsies from patients without known disease of the peripheral nervous system. Enlargement of cross-sectional area due to an increase in connective tissue elements was commonly present in the ulnar nerve at the elbow and in the median nerve under the flexor retinaculum. Renaut bodies were also prominent at these two sites. The connective tissue changes did not appear to be related to the presence or absence of nerve fibre damage. When nerve fibres were teased apart and examined individually, localised changes were found at the elbow in 5 ulnar nerves and under the flexor retinaculum in 5 median nerves. The changes were mild and transverse sections at the same levels showed few abnormalities. However, the changes were similar in character to those described previously in experimental animals with entrapment syndromes. They are therefore considered to be valid evidence of sub-clinical entrapment in apparently unaffected human subjects.

Acute Disease↗
PubMed1973

Development of extrapyramidal symptoms in hypertensive patients treated with diazoxide.

Extrapyramidal symptoms developed a variable time after the start of treatment with oral diazoxide in 15% of a series of 100 severely hypertensive patients. Six illustrative cases are described. Treatment with diazoxide could be continued in four of these. The symptoms are usually controllable either by dosage adjustment or by the use of diazepam or procyclidine. There was no evidence of irreversibility of the extrapyramidal syndromes observed.

Adult↗
PubMedDate not supplied

Autobiographical experience and word meaning.

The role of current personal experience in understanding of word meaning was investigated in a patient, WM, who suffers from semantic dementia. The study was prompted by the observation that WM, despite being severely impaired on formal tests of word comprehension and naming, retained a range of vocabulary pertaining to her daily life. If autobiographical experience has a general facilitatory effect, then this should affect which concepts are retained and which lost, but not influence the quality of that conceptual knowledge. Conversely, if personal autobiography has a direct role in investing concepts with meaning, then WM's understanding of nominal terms that she uses spontaneously in conversation ought not to be normal, but should be constrained by the autobiographical context in which she uses those terms. WM could define nouns and noun phrases drawn from her conversational vocabulary, but her definitions had a markedly autobiographical quality. Moreover, WM was extremely impaired in her ability to define new noun phrases, constructed by combining words from her conversational vocabulary (e.g. "dog licence", constructed from "driving licence" and "dog"; "oil field" constructed from "oil" and "field"). It was concluded that WM does not have normal conceptual understanding of nouns and noun phrases that she uses appropriately in conversation. Her understanding is narrow and autobiographically constrained. The findings, which suggest an interactive relationship between autobiographical and semantic memory, have implications for understanding of the progressive breakdown of semantic knowledge.

Amnesia↗