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Biomedical subjects

S Harrison

Publications and source records attributed to S Harrison.

At least 145 records · Page 8Linked to original sources
PubMed1988

Disconnection of the amygdala from visual association cortex impairs visual reward-association learning in monkeys.

Cynomolgus monkeys (Macaca fascicularis) were trained in a task that assessed their ability to associate visual stimuli with food reward. Acquisition of stimulus-reward associations was measured under 2 conditions, a 2-stimuli acquisition condition and a 1-stimulus acquisition condition. On each trial in the 2-stimuli condition, the positive (correct) and negative (incorrect) stimuli were presented side by side and the animal chose one by touching it; if the choice was correct, a food reward was dispensed. On each trial in the 1-stimulus condition, either the positive or the negative stimulus was presented alone; if the stimulus was the positive, it was followed by reward delivery, regardless of the animal's response to it, and if it was the negative, it was not followed by reward delivery. Thus, reward delivery was contingent upon the animal's response to the stimuli in the 2-stimuli condition but not in the 1-stimulus condition. The effect of acquisition trials under these 2 conditions was measured, in both conditions, by the animal's subsequent choice when presented with the 2 stimuli side by side. Following preoperative training in this task, the animals were first subjected to unilateral ablation of the inferotemporal cortex. This operation had little effect on the animals' learning ability. Then, the amygdala was ablated in the hemisphere contralateral to that in which the unilateral inferotemporal ablation had been carried out. This combination of crossed unilateral lesions of the amygdala and of the inferotemporal cortex, which disconnects the amygdala from the output of visual association cortex, produced a profound impairment in stimulus-reward-associative learning.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1987

Immunohistochemical localization of c-erbB-2 in human breast carcinomas.

This study was carried out to assess the utility of antibodies raised to synthetic peptides of the predicted sequence of the c-erbB-2 gene product to identify immunocytochemically those tumours overexpressing this putative transmembrane receptor. Staining with rabbit antiserum 21N gave the best correlation with gene amplification and did not stain the membrane of any of the normal tissues at the dilution which strongly stained the membrane of any of the normal tissues at the dilution which strongly stained the amplified tumours. No significant correlation was found with lymph node involvement, epidermal growth factor receptor status or with oestrogen receptor levels. Of the 12 out of 34 cases which demonstrated c-erbB-2 gene amplification in the primary tumour, two had lymph node metastases which were also positive immunocytochemically. Fourteen other cases which had lymph node metastases were negative in the primary tumour and in the metastases. These tumours all showed strong membrane positivity. A comparison of modified methacarn and formol saline fixation demonstrated an increased sensitivity with the former, but the staining pattern was unaltered. This small but extensively studied group of cases has indicated that increased c-erbB-2 protein can be identified routinely in fixed tissue sections, making it possible to carry out extensive studies to look for clinical correlates, but also to assess the stage in tumour progression at which the increased expression occurs and whether it correlates with any potentially premalignant condition.

Breast Neoplasms↗
PubMed1987

Amygdalectomy and disconnection in visual learning for auditory secondary reinforcement by monkeys.

Nine monkeys in 3 groups took part in an experiment on visual discrimination learning set in an automatic apparatus. Each new visual discrimination problem was solved using auditory secondary reinforcers. Primary food reinforcement was delivered only after a new problem had been solved to a criterion, and the problem was then replaced by a new one; thus, within-problem learning relied purely on secondary and not on primary reinforcement, but the secondary reinforcers were associated with primary reinforcement. Bilateral amygdalectomy severely retarded within-problem learning. Disconnection of the amygdala from auditory input, by crossed unilateral lesions of amygdala and of auditory cortex combined with forebrain commissurotomy, had a similar effect to that of bilateral amygdalectomy. Disconnection of the amygdala from visual association cortex left learning unimpaired. Thus, for normal performance in this task, interaction of the amygdala with the sensory modality of the secondary reinforcer was essential, but interaction of the amygdala with the sensory modality of the discriminative stimuli was not necessary. It was concluded that the amygdala is involved in associating stimuli with the primary reinforcing attributes of food reward, and not with its other attributes.

Amygdala↗
PubMed1986

Labour relations in health services management.

'Labour relations' or 'industrial relations' refers to employer-employee relations which are both economic as in matters of pay and conditions, and managerial, i.e. the political relationships between management and employees, collectivized through trade unions and professional associations. This paper traces the development of managerial relationships as illustrated by experiences in the British National Health Service particularly over the past 20 years focusing on groups of actors--management (within which may be distinguished government and local managers), health professional workers and other workers--whose interactions need to be studied if managerial relations within health services are to be satisfactorily analysed. We conclude that, although until recently, developments in management have had little impact upon worker behaviour outside unskilled groups, changing economic and other circumstances could create the conditions in which stronger managerial control over professional workers might emerge.

Forecasting↗
PubMed1985

Assessing the needs of the elderly using unsolicited visits by health visitors.

Thirty-five percent of patients over 70 years old who received an unsolicited visit by a health visitor were found to have previously unidentified needs. In all, 71% of the 110 patients surveyed were found to have problems involving mobility, communication or caring for themselves. Most of their needs were social ones. It was concluded that unsolicited visiting by health visitors was efficient use of time by members of the primary health care team. Changes in practice administration are suggested to improve access to medical care for elderly patients.

Aged↗
PubMed1984

Consensus management in the British National Health Service: implications for the United States?

Most operational services within the reorganized British National Health Service are managed by local teams: medical specialist, general practitioner, nurse, administrator, and finance officer. Decision by consensus has worked well to integrate services in a complex and fiscally constrained system. As larger and more formal systems of health care emerge in the United States, the British experience may be relevant.

Administrative Personnel↗
PubMed1983

Excreta disposal facilities and intestinal parasitism in urban Africa: preliminary studies in Botswana, Ghana and Zambia.

The relationships between intestinal parasitism and excreta disposal technologies in Gaborone (Botswana), Ndola (Zambia) and Kumasi (Ghana) were investigated. Parasitic prevalence and intensity rates amongst groups of urban residents having similar socio-economic status and housing, but different excreta disposal technologies, were compared. In Gaborone, there was no evidence of a difference in intestinal parasitism between those using aqua privies and having access to public taps and those in identical houses enjoying flush toilets, in-house water connections and showers. In Ndola, the group with sewered aqua privies had larger houses, cleaner toilets, better water supplies, longer residence and more people in paid employment than the groups using pit latrines or communal flush toilets. Despite this, the sewered aqua privy users were not found to be different from the other groups with regard to hookworm and protozoal infection but had significantly higher Ascaris infection rates. In Kumasi, despite the differences in toilet type--from squalid communal aqua privies, through often fouled bucket latrines to well-maintained flush toilet systems--and despite also the differences in water provision, no evidence was obtained of any differences in intestinal parasitism between the groups studied. These findings suggest that the provision of superior water and sanitation facilities to a small cluster of houses, or to houses scattered through an area, may not protect those families from infection if the over-all level of faecal contamination of the environment is high. The sample sizes and response rates achieved in this study were low and follow-up studies, employing the same methodology but with larger samples, are recommended.

Adolescent↗