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Biomedical subjects

R Corcoran

Publications and source records attributed to R Corcoran.

At least 37 records · Page 2Linked to original sources
PubMed1995

The risk of hepatitis A from sewage contamination of a water supply.

The drinking water supply of a town became contaminated with sewage. The town's population was surveyed to determine the baseline prevalence of hepatitis A antibodies and to establish whether an associated outbreak of hepatitis A had occurred. Samples of saliva were obtained from 540 people in 200 randomly selected households, and tested for IgG and IgM antibodies to hepatitis A. Fifty-six per cent (279/495) were susceptible to hepatitis A and 43% (213/495) immune as a result of previous infection. Immunity was directly related to age; those who were immune were significantly older than those who were susceptible (mean ages: 43.5 years and 19.0 years; p < 0.0001). Six people were found to have had a recent infection with hepatitis A, but exposure to hepatitis A during the water pollution incident was possible in only one case. The results offer no evidence that this incident caused an outbreak of hepatitis A, but the study has provided useful epidemiological data on hepatitis A.

Adolescent↗
PubMed1995

Schizophrenia, symptomatology and social inference: investigating "theory of mind" in people with schizophrenia.

It has been proposed that certain psychotic symptoms associated with schizophrenia reflect a deficit in the ability to appreciate other people's mental states (Frith, 1992). This notion is tested using a newly devised task examining the capacity to infer intentions behind indirect speech. The findings support the notion that some patients with schizophrenia have difficulties with tasks requiring 'theory of mind' skills and that this deficiency is symptom specific. The findings are discussed with reference to the cognitive skills which may be involved in the performance of tasks requiring social inferences.

Adult↗
PubMed1995

The role of the right temporal lobe in card sorting: a case study.

It has been demonstrated previously that performance on the modified Wisconsin Card Sorting Task (Nelson, 1976) is compromised by hippocampal sclerosis, particularly of the right hemisphere (Corcoran and Upton, 1993). Further evidence in support of this claim is presented here in the form of a case study. The findings from this case demonstrated that performance on the same task was not impaired following a right sided frontal lobectomy but was found to be deficient consequent to seizure recurrence in the right temporal lobe and following right temporal lobe removal. The clinical and theoretical significance of this case is discussed.

Adult↗
PubMed1995

Illness in a community associated with an episode of water contamination with sewage.

Following an episode of water contamination with sewage in a rural Irish town, a community-wide survey of gastrointestinal-associated illness and health service utilization was conducted. Random sampling of households yielded residents who were surveyed using a self-administered questionnaire. Of 560 respondents from 167 (84%) households, equal proportions lived in areas known to have been exposed and unexposed to the contaminated water, although 65% of subjects reported using contaminated water. Sixty-one percent of subjects met the case definition. The most common symptoms among cases were abdominal cramps (80%), diarrhoea (75%), appetite loss (69%), nausea (68%) and tiredness (66%). Mean duration of illness was 7.4 days. Only 22% of cases attended their general practitioner. Drinking unboiled water from the exposed area was strongly associated with being a case. A substantial degree of community illness associated with exposure to contaminated water was observed. The episode ranks as one of the largest reported water-borne outbreaks causing gastrointestinal illness in recent times.

Disease Outbreaks↗
PubMed1994

The role of the right hemisphere in the interpretation of figurative aspects of language. A positron emission tomography activation study.

We investigated cerebral activity in six normal volunteers using PET to explore the hypothesis that the right hemisphere has a specific role in the interpretation of figurative aspects of language such as metaphors. We also mapped the anatomical structures involved in sentence comprehension. During regional cerebral blood flow measurement subjects were asked to perform three different linguistic tasks: (i) metaphorical comprehension; (ii) literal comprehension of sentences; and (iii) a lexical-decision task. We found that comprehension of sentences compared with the lexical-decision task, induced extensive activation in several regions of the left hemisphere, including the prefrontal and basal frontal cortex, the middle and inferior temporal gyri and temporal pole, the parietal cortex and the precuneus. Comprehension of metaphors was associated with similar activations in the left hemisphere, but in addition, a number of sites were activated in the right hemisphere: the prefrontal cortex, the middle temporal gyrus, the precuneus and the posterior cingulate. We conclude that the interpretation of language involves widespread distributed systems bilaterally with the right hemisphere having a special role in the appreciation of metaphors.

Adult↗
PubMed1994

Effects of vigabatrin on partial seizures and cognitive function.

Forty five patients with refractory partial seizures were studied in a prospective, randomised, placebo controlled, add on, parallel group, double blind trial of the new antiepileptic drug vigabatrin (1.5 g twice daily) followed by open treatment. Seizure frequency was monitored throughout an eight week baseline, 20 weeks double blind, and up to 18 months of open vigabatrin treatment. Cognitive function, including measures of memory and concentration, mood, and behaviour were assessed at baseline and again during the 20th week of treatment. Vigabatrin was associated with a significant reduction in a measure of motor speed and overall score on a design learning test in the first 20 weeks of treatment. In comparison with the baseline period, vigabatrin treatment was associated with a significant reduction in median complex partial seizure frequency four to 12 and 12 to 20 weeks after commencing vigabatrin (-66% and -69% in the vigabatrin group, +50% and +25% in the placebo group). Ten of 20 patients on vigabatrin and four of 23 on placebo showed a > 50% reduction in complex partial seizure frequency in the last eight weeks of double blind treatment. At least 60% of responders had maintained the response to vigabatrin when assessed during the open phase of the trial at 44 weeks. Two patients discontinued vigabatrin because of depression, which resolved on drug withdrawal.

Adolescent↗
PubMed1994

Safety and efficacy of nebulized lignocaine in patients with cancer and breathlessness.

Although anecdotal reports suggest nebulized lignocaine may help breathlessness in patients with cancer this has not been examined formally. We report a pilot study comparing nebulized lignocaine 100 mg and 200 mg with saline in six patients with cancer who were breathless at rest. Nebulized lignocaine was well tolerated apart from mild bronchoconstriction in two patients after the 200 mg dose and the unpleasant taste; serum concentrations were below levels at which toxicity has been reported. The effort of breathing (measured on a visual analogue scale) did not differ between treatments, whereas the distress of breathing was less after saline than after either dose of lignocaine. These findings do not support the reported benefits of nebulized lignocaine.

Administration, Intranasal↗
PubMed1993

A role for the hippocampus in card sorting?

This study examines the performance of three groups of patients with epilepsy on three measures typically used to assess the integrity of the frontal lobes: the Modified Wisconsin Card Sorting Test (MWCST), verbal fluency and the Stroop test. The groups comprised sixteen patients with clearly defined hippocampal sclerosis, thirteen patients with unilateral temporal lobe seizure onset and eighteen patients with unilateral frontal lobe onset. Results demonstrated that performance on the MWCST was most compromised by hippocampal sclerosis. These patients took longer to complete the task, achieved fewer categories and made more perseverative errors than patients in the other groups. In contrast, verbal fluency and performance on the Stroop test were less affected by the presence of hippocampal sclerosis. These results have both clinical and theoretical significance. It is argued that patients with hippocampal damage perform poorly on the MWCST because of the heavy working memory requirements of the test. Cautious use of this test as a tool to localise seizure origin in patients with complex partial seizures is therefore recommended. The findings are discussed in terms of Gray's (1982) model of the hippocampus as a comparator of actions.

Adolescent↗
PubMed1993

Hepatitis B in the non-residential mentally handicapped population.

This study describes seroprevalence and risk factors for hepatitis B in seven centres caring for non-residential mentally handicapped individuals. Overall, 11% were hepatitis B marker seropositive and 4% had the hepatitis B surface antigen (HBsAg). Male sex and increasing age were associated with seropositive status, and Down's syndrome was associated with the presence of HBsAg. Immediate family members of those with hepatitis B markers were screened and 22% had evidence of hepatitis B markers. Forty-one family members were identified when the mentally handicapped individual was HBsAg positive and of these 13 (32%) were seropositive. This study demonstrates that hepatitis B is a problem for the non-residential mentally handicapped population and confirms the risk of infection to their immediate families.

Adolescent↗
PubMed1993

Epilepsy and poor memory: who complains and what do they mean?

The aim of this study was to increase the understanding of the major causes of memory complaints made by people with epilepsy. Neuropsychological test performance, patients' self-reports of memory failures and the use of memory support strategies were compared in two groups of 30 patients with epilepsy differing in level of memory complaints. Those reporting significant memory difficulties performed more poorly on two of the six measures of memory administered. Age of onset of seizures was significantly later in the 'complaining' group but none of the other treatment and epilepsy variables considered differentiated the groups. Patients who complained of memory problems, however, were significantly more depressed and anxious than non-complainers. These findings may have implications for memory rehabilitation interventions in the population.

Adult↗
PubMed1992

Memory failure in epilepsy: retrospective reports and prospective recordings.

People with epilepsy frequently complain of memory difficulties and previous research provides some support for the existence of memory dysfunction. However, our clinical experience is that many who report serious memory difficulties perform quite adequately on psychometric tests. One explanation for this discrepancy is that these patients are exaggerating the difficulties they encounter in their daily lives. This study aimed to examine this hypothesis by comparing patients' retrospective reports of memory to prospective recordings of everyday memory failures. Results demonstrated that far from over-emphasizing their daily problems, people with epilepsy believed fewer memory failures occurred when rated retrospectively than was indicated by a prospective recording device. While there was good agreement between the methods of assessing memory failures for the frequency of their most troublesome difficulties, subjects tended to underestimate the incidence of the less pervasive everyday problems. The results are interpreted through the theory of memory introspection proposed by Herrmann.

Adult↗
PubMed1992

Everyday memory failures in people with epilepsy.

In a series of studies, we have explored the nature of memory problems experienced by people with epilepsy. By means of a questionnaire, the first study surveyed everyday memory failures experienced by 742 people with epilepsy. Findings revealed a high level of failures that were associated with later age of onset of seizures and raised levels of anxiety and depression. A second smaller prospective study confirmed these findings and suggested that patients with epilepsy had underestimated the frequency of memory complaints when assessed retrospectively. The third study investigated the relationship between self-reported memory failures and neuropsychological test performance. A measure of verbal recall was the best predictor of reported memory failures. Again, older age of onset and mood were found to be pertinent variables in relation to memory complaints.

Age Factors↗
PubMed1985

An assay to determine the kinetics of RNA cleavage.

To evaluate some synthetic catalysts that mimic ribonuclease, a quantitative assay has been developed that measures the number of phosphate diester bonds cleaved in a polymeric RNA substrate. This assay involves determining the number of 5'-oligonucleotide termini produced during the cleavage, using polyuridylic acid as the substrate. Samples withdrawn from the kinetic run are treated with venom exonuclease (phosphodiesterase I), and the increase in the concentration of uridine is determined by high-performance liquid chromatography. A related assay has been developed to monitor the catalyzed cleavage of the dinucleotide uridylyl(3'----5') uridine (UpU).

Chromatography, High Pressure Liquid↗