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Biomedical subjects

J Powell

Publications and source records attributed to J Powell.

At least 181 records · Page 10Linked to original sources
PubMed1993

The effects of anti-hypertensive medication on learning and memory.

1. The aim of the study was to investigate whether there were differential effects of three different anti-hypertensive medications (cilazapril, atenolol, nifedipine) on cognitive function. 2. A sub-group of patients participating in a large clinical trial of these three drugs, randomly allocated between the three drug conditions, received cognitive assessment at two points before the commencement of treatment and then after 12 and 24 weeks of treatment. Seventy-six patients began treatment, and 55 completed the full course. 3. Tests of learning and memory were designed specially for the study, with a different but comparable version administered on each assessment occasion, in a fixed order. 4. No significant differences between drug groups were found in any index of learning or memory, at any testing occasion. The results were the same whether or not treatment non-completers were included in the analysis.

Adult↗
PubMed1993

Subjective craving for opiates: evaluation of a cue exposure protocol for use with detoxified opiate addicts.

Cue exposure has been advocated as an intervention for reducing relapse rates in detoxified addicts, by extinguishing classically conditioned drug effects/craving which may have developed. Several studies with alcoholics have found cue exposure to be associated with reductions in craving, but no controlled study has yet shown such an effect in opiate addicts. The present controlled group design evaluates a protocol which draws from experience in the treatment of anxiety and requires that each stimulus exposure should be continued until within-session habituation has occurred. It also explores whether there is any benefit of using a 'cognitive aversion' strategy during cue exposure, based on the social learning analysis that craving derives from expectancies of positive drug effects. A total of 21 detoxified in-patients were randomized to routine ward treatment plus two sessions of either cue exposure (Group E) or cue exposure and cognitive aversion (Group E/CA), or to routine treatment alone (Group C). A specially designed Craving Test was carried out before and after treatment, to assess change in cue-elicited reactions. The two treated groups showed significantly greater reductions in craving than Group C, but did not differ from each other. The cue exposure protocol has therefore been adopted for use in an ongoing clinical trial.

Adult↗
PubMed1993

Sweet taste transduction in hamster taste cells: evidence for the role of cyclic nucleotides.

1. Physiological and behavioral responses to artificial sweeteners, natural sweeteners, and cyclic nucleotides were assessed using two techniques. An extracellular "in situ" technique recorded action potentials from fungiform taste buds and the two-bottle preference test measured behavioral preferences for the different sweeteners. 2. Two high-potency sweeteners, NC-00274-01 (NC01) and NC-00044-AA (NCAA), were preferred over water at micromolar concentrations. Saccharin and sucrose were likewise preferred, but at millimolar concentrations. 3. Bursts of action currents were elicited by sucrose at 200 mM, saccharin at 20 mM, and NCAA at 0.1 mM. A concentration-response curve for the high-potency sweetener NC01 revealed a threshold concentration of 1 microM and a saturation concentration of 100 microM. No responses were elicited by aspartame. 4. The responses to different sweeteners adapted rapidly at saturating concentrations. With NC01, adaptation was concentration dependent: at threshold the response adapted very slowly if at all. Adaptation increased with increasing concentration. 5. Membrane-permeant analogues of adenosine 3',5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate mimicked sweeteners in their ability to elicit a response. This occurred with high fidelity: nearly every taste bud that responded to sweeteners also responded to the nucleotides and every sweet-unresponsive taste bud was nucleotide unresponsive. 6. The sweet responses and nucleotide responses occurred in the absence of permeant apical cations and were not enhanced nor diminished by the presence of such cations. Amiloride had no effect on the sweet response.

Animals↗
PubMed1992

Group therapy in a detoxification unit.

The aim of this study was to discover residents' perceptions of supportive group therapy conducted as part of a week-long alcohol and other drug detoxification programme. A brief questionnaire was adapted from Yalom's Q sort and administered to 105 residents at the end of group sessions. The instrument elicited ratings of the extent to which each of ten outcomes had occurred. Outcomes rated positively included universality, the instillation of hope, group cohesion and guidance.The results are interpreted as providing support for the continuation of non-confrontational group therapy in the detoxification unit, with an increased emphasis on brief advice-giving.

Journal Article↗
PubMed1992

The rising trend in oesophageal adenocarcinoma and gastric cardia.

The incidence of cancer of the oesophagus and stomach in the West Midlands region of England have been analysed for the 25 years 1962-86. Overall, cancer of the oesophagus is increasing (from 3.45 per 100,000 in 1962-66 to 4.37 in 1982-86) and stomach cancer is decreasing (19.22 and 16.54 respectively). However, when analysed by histological type and subsite the picture is very different. In oesophagus, squamous cell carcinoma shows only a slight increase whereas for adenocarcinoma the increase is highly significant (from 0.14 to 0.76). In stomach, cardia shows a very similar pattern to adenocarcinoma of oesophagus (increasing from 0.75 to 2.96) but pyloric antrum is decreasing (from 2.63 to 2.32). The rapid changes in investigative procedures over the period have resulted in increasing numbers with histological confirmation and subsite specification but despite these confounding factors, comparative analyses still indicate a real increase in adenocarcinoma of oesophagus and cardia. Although the incidence of both are greater in men than in women, the proportional rates of increase, particularly for cardia, are very similar in both sexes, indicating a common aetiological factor or factors. Analysis by social-economic group reveals that the increases observed are not uniform throughout the population but are relatively higher in professional classes (1 and 2).

Adenocarcinoma↗
PubMed1992

Classical conditioning and cognitive determinants of subjective craving for opiates: an investigation of their relative contributions.

Subjective craving for drugs is frequently reported by detoxified addicts. Explanatory models emphasizing classical conditioning (CC) and cognitive mechanisms have been proposed, and the mechanisms postulated by the two approaches are discussed here. There are three major variants of the CC model, arguing that craving is associated with conditioned changes which are respectively drug-agonistic, opponent-process, or withdrawal reactions. The cognitive model highlights the role of 'outcome expectancies' as determinants of both appetitive and avoidant motivations. The present investigation has identified correlates of craving predicted by the above models, and tested them empirically. Detoxified opiate addicts participated in in a Craving Test requiring them to rate their craving, physical state, and emotions during exposures to both neutral and drug-related material. Other measures, including personality and outcome expectancies for drug use, were also taken, and interrelationships among the variables were explored statistically. Whilst some of the predictions of the CC formulations were borne out, the cognitive model received more consistent support. The theoretical and treatment implications of these data are considered.

Adult↗
PubMed1991

Models of arterial aneurysm: for the investigation of pathogenesis and pharmacotherapy--a review.

Arterial aneurysms continue to provide a clinical challenge for neurosurgeons and vascular surgeons. Many different animal models have been developed in which the pathogenesis, growth, rupture and treatment of these aneurysms can be investigated. These animal models have been reviewed here, with the focus on saccular aneurysms in the muscular cerebral arteries and fusiform aneurysms in the elastic aorta. Consideration of the animal models described indicates appropriate experimental models and new directions for the development of improved models in which to test the effects of pharmacologic factors in limiting the growth and rupture of aneurysms.

Aneurysm↗
PubMed1991

Staging carcinoma: its value in cancer of the larynx.

Three thousand four hundred and forty-five cases of cancer of the larynx were examined and 3,235 assigned to their TNM group. While good correlation with prognosis could be seen, the value of the detailed subsite (as opposed to the main laryngeal regions) was limited to defining T1a and T1b and aiding that of T2. T status gives some indication of prognosis, but the N status is of almost overriding importance.

Female↗
PubMed1991

Primary treatment of cancer of the larynx.

Analysis of 3,445 cases of cancer of the larynx with a follow-up of 99.8 per cent shows that over a period in which the survival has improved neither the modality of the treatment nor the severity of the cancer has changed. Improved survival may be due to socioeconomic factors or an improvement in the quality of treatment.

Combined Modality Therapy↗
PubMed1991

Modulation of the cancer susceptibility measure, adenosine diphosphate ribosyl transferase (ADPRT), by differences in low-dose n-3 and n-6 fatty acids.

Adenosine diphosphate ribosyl transferase (ADPRT) is related to oxidants, and lower values for ADPRT in white cells suggest increased cancer susceptibility. Ordinarily, oxidants are generated intracellularly via metabolism of n-6 fatty acids common in western diets. However, n-3 fatty acids in fish oils might limit oxidants via competitive inhibition of key enzymes, elevate ADPRT, and lower cancer risk. In this controlled trial, 47 women were assigned either lecithin (an n-6 fatty acid, 7.2 g daily) or eicosapentaenoic acid-docosahexaenoic acid (n-3 fatty acids, 1.5 g daily) for six weeks, and 45 women completed all four visits. After six weeks, ADPRT increased by 9.3 +/- 10.8% (SD) for the n-3 fatty acid group relative to the n-6 fatty acid group. For the subset of 39 women with good compliance, ADPRT increased by 20.9 +/- 11.1% (nonparametric p = 0.039). This increase persisted after adjustment for regression to the mean. The trial suggests a "normalizing" effect of low-dose n-3 fatty acids on the ADPRT measure.

Disease Susceptibility↗
PubMed1991

Post-laryngectomy stomal recurrence: tumour implantation or paratracheal lymphatic metastasis?

In the treatment of obstructing laryngeal cancer, an association has often been noted between emergency tracheotomy for airway relief and subsequent post-laryngectomy stomal recurrence. It is however unclear whether this is due to tumour implantation in the tracheotomy track, or paratracheal lymph node metastasis. To investigate the pathophysiology of stomal recurrence, the recurrence rate and clinical outcome of 26 cases of T3N0M0 glottic cancer treated with emergency tracheotomy and subsequent laryngectomy were analysed, and compared with 65 stage-matched cases treated with laryngectomy alone. Analysis shows the 'emergency tracheotomy' group to have a very poor prognosis with a higher incidence of recurrence at the stoma, and also in the regional lymph nodes. These findings suggest that paratracheal lymph node metastasis is an important mechanism in the development of stomal recurrence and thus has considerable implications for the prevention of such a recurrence following laryngectomy in the patient presenting with malignant airway obstruction.

Carcinoma, Squamous Cell↗
PubMed1991

Eosinophilic pustular folliculitis (Ofuji disease) in childhood: a review of four cases.

Four children under 2 years of age were treated at our hospital in the last three years with a recurrent vesiculopustular eruption of the scalp, variably extending to the face and limbs. All cases followed a cyclical pattern. Three of the children had a moderate response to topical steroids, and one went into remission after a two-month course of erythromycin. Ethnic origin may be an important predisposing factor. Histologically, all patients showed a moderate mixed inflammatory infiltrate with numerous eosinophils centered around hair follicles. Peripheral white blood cell count showing leukocytosis with eosinophilia was observed in those cases measured, but no consistent immunologic abnormalities could be identified.

Eosinophilia↗
PubMed1991

Postwithdrawal exposure treatment to prevent relapse in opiate addicts: a pilot study.

A major problem in treating opiate addiction is relapse within a few months after withdrawal. Learning models of relapse offer some promise toward understanding this problem. The present pilot study examines whether cue-exposure treatment to drug-related cues, in hospital and real life, might reduce relapse. Fourteen opiate addicts were withdrawn on clonidine over 6 days, and 10 of those were exposed to drug-related cues in hospital for 1 week and in real life for another. There were then followed as outpatients up to 6 months. Craving was elicited in half of the 10 patients exposed to drug cues who showed within- and between-session habituation. Four cases were opiate-free at 6 months follow up and 1 at 3 months. Half of the cases had relapsed to heroin at various times up to 6 months. Habituation to craving responses was not obviously related to outcome whereas vocational factors were. The operational use of craving in research is discussed.

Adult↗
PubMed1991

The natural history of low grade non-Hodgkin's lymphoma and the impact of a no initial treatment policy on survival.

The natural history of low grade lymphoma and the influence of a 'no initial treatment' policy on survival were studied retrospectively in a group of 153 patients with stage II-IV low grade non-Hodgkin's lymphoma. The median follow-up was 85 months (range 45-229 months) and median survival of 50 months (range 14-220 months). Favourable outcome was significantly associated with the absence of B symptoms and a centroblastic/centrocytic (cb/cc) diffuse and follicular histological subtype and was inversely associated with increasing age. No significant differences in survival were found according to patient gender, site or stage of disease or whether the patients were participants in a clinical trial. Importantly, there was no survival disadvantage amongst the 56 patients who were initially untreated compared to those receiving other treatment modalities: initially untreated patients had a median survival of 75 months; 56 per cent were alive at 5 years and the median treatment free interval was 33 months. This favourable outcome persisted even after adjustment for other important prognostic variables. Further studies are needed to identify the characteristics of those patients with indolent disease in whom treatment may be deferred without adversely affecting survival.

Adult↗