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Biomedical subjects

E Kay

Publications and source records attributed to E Kay.

At least 37 records · Page 2Linked to original sources

DNA quantification is technically feasible and of value in cervical smear samples: possible applications for determination of progression in low grade dyskaryosis.

This study evaluates the feasibility of DNA analysis of cervical intraepithelial neoplasia III (CIN III) lesions on cervical smear and formalin-fixed paraffin-embedded tissue (FFPET) blocks with a view to extending this type of analysis to milder grades of dyskaryosis. DNA ploidy was determined by image analysis using a CAS 200 Image Analyser. Seventeen patients with a diagnosis of CIN III were studied. Results show that all smear and tissue samples were non-diploid with nine aneuploid and eight tetraploid lesions. In 6/7 patients whose smears and corresponding biopsies were examined there was complete agreement as to the DNA profile. We conclude that DNA quantification is technically feasible in archival, routinely prepared cervical smears. This technique should now be applied to CINI and CINII cervical smears to determine if it is of value in identifying those lesions that will progress to CIN III. This study is particularly timely with the possibility in the near future of estimation of ploidy by image analysis using instruments such as the Highly Optimized Microscope Environment (HOME) system.

Aneuploidy

The relevance of health state utilities to lower third molar surgery.

A study of the attitudes of 102 arts and science undergraduate students was carried out to establish relative utility values, that is the participants own assessments, for possible outcomes of surgical intervention and non-intervention in lower third molar management. Using a standardised visual analogue scale, respondents were asked to rate 17 outcomes of treatment presented to them by means of short descriptions (vignettes). Ranking of mean utility values showed that post operative complications were considered to be a greater handicap than the sequelae of leaving third molars in situ. The respondents considered that the effects of irreversible lingual and inferior dental nerve damage reduced health to a major degree, and that normally encountered post operative complications such as moderate pain, swelling and trismus were a greater handicap than recurrent mild/moderate pericoronitis.

Adult

Public health aspects of third molar surgery. The effect of surgeons' treatment thresholds on efficiency and effectiveness.

Disease associated with third molars is being recognised increasingly as a public health problem in terms both of rising incidence and of appropriate use of resources. Since minor alterations in treatment philosophy can have a substantial impact on the efficiency and effectiveness of oral surgery services, this study examines the sensitivity and specificity of oral surgeons' decisions and uses Receiver Operator Characteristics (ROC) analysis to investigate their ability to detect and make appropriate judgements about teeth which need extraction according to established criteria. The study shows that the seniority of the surgeon making the treatment decisions had no significant effect on the decisions made and also demonstrated wide variations between the treatment plans made by individual clinicians. It is clear from this study that if an efficient and effective service for the treatment of third molar disease is to be commissioned, policy decisions about criteria for intervention must be made by health service purchasing authorities, adhered to by secondary care providers, and shared with the primary care practitioners who refer patients for treatment.

Decision Making

Oxygen free radical activity in experimental colonic carcinoma.

Oxygen free radical activity has been implicated in carcinogenesis through DNA lysis. This study measured chemiluminescence and superoxide dismutase (SOD) inhibition as an index of oxygen free radical activity in azoxymethane-induced colonic carcinoma. After 3 weeks of acclimatization, ten Fisher 344 rats were injected with azoxymethane (7 mg kg-1 week-1) over 10 weeks. All animals were killed at 37 weeks and colonic mucosa (5-25 mg wet weight) was sampled from sites of histologically confirmed gross tumour and sites 3-5 cm distant from tumour as well as from ten paired normal controls. The samples were processed in buffered luminol and chemiluminescence was measured in a luminometer. Each sample was then placed in a solution of SOD for 3 min before a second chemiluminescence estimation. Mean(s.e.m.) chemiluminescence from control mucosal samples decreased from 8.1(1.0) to 3.9(1.1) mV per 100 mg tissue (P < 0.05) after incubation in SOD, suggesting that oxygen free radical activity was being measured. There was an increase to 20.2(0.9) mV per 100 mg in azoxymethane-treated colon remote from tumour and to 53.9(2.1) mV per 100 mg at tumour sites; both were reduced significantly after incubation with SOD to 6.7(0.7) and 11.0(0.8) mV per 100 mg respectively (P < 0.001). Chemiluminescence was significantly increased in azoxymethane-induced colonic carcinoma, both remote from and maximally at the tumour site, suggesting a field change in carcinogenesis associated with oxygen free radical activity.

Animals

Stress ulceration and gastric mucosal cell kinetics: the influence of prophylaxis against acute stress ulceration.

Acute gastric stress ulceration occurs frequently in severely ill patients. Mucosal ischemia is central to the etiology of stress ulceration. The ability of the mucosa to restore continuity when damaged is one of the most important of the local defence mechanisms against injury. The aims of this study were to investigate this restitutive process during stress ulcer formation and to determine the effect of prophylaxis against stress ulceration on gastric mucosal cell kinetics. Nuclear DNA was radiolabeled in vivo with tritiated thymidine, and after autoradiography the position and number of labeled cells along the gastric mucosal gland were determined. Wistar rats were studied immediately and 48 hr after cold restraint stress. The labeling index in the proliferative zone of the gastric mucosa was significantly suppressed immediately after stress (12.58% vs 16.81% for unstressed controls, P < 0.001). This effect persisted for 48 hr after stress (9.89% vs 16.35% for unstressed controls, P < 0.001). Prophylaxis against stress ulceration with cimetidine or allopurinol prevented this suppression of gastric mucosal cell kinetics and promoted early migration of labeled cells towards the surface of the mucosal gland. Allopurinol prophylaxis was associated with migration of mucosal cells immediately following stress greater than that following cimetidine prophylaxis (14.0% vs 9.3% surface layer labeling index, P < 0.01). Allopurinol, a xanthine oxidase inhibitor, reduces oxygen free radical production during ischemia reperfusion injury. These results emphasise the importance of the gastric mucosal defence mechanisms in protection against injury and indicate the role of ischemia in the aetiology of acute gastric stress ulceration.

Allopurinol

Ploidy changes between diagnosis and relapse in childhood renal tumours.

Ploidy patterns, analysed by flow cytometry (FCM) and image analysis (IA), were investigated at relapse in a group of six children with renal tumours [five Wilms' tumour (WT) and one bone metastasizing renal tumour of childhood (BMRTC)] and results compared with diagnostic profiles. IA detected one or more aneuploid populations in five of 12 tumours which were diploid on FCM. Patterns in three of six patients [two with unfavourable histology (UH) and one with favourable histology (FH)] were aneuploid at diagnosis and relapse, two patients (one FH, one BMRTC) developed aneuploid features at relapse and one patient with a tetraploid tumour was diploid at relapse. Histology patterns were similar at diagnosis and relapse in all patients. Three of six patients (two UH, one BMRTC) have died of disease. This report highlights (1) the superiority of IA over FCM in detecting aneuploid populations and (2) changes in ploidy status which have not previously been reported in these tumours. Overinterpretation of DNA status at relapse may prove misleading.

Aneuploidy

Self-efficacy and health behavior among older adults.

Self-efficacy has a well-established, beneficial effect on health behavior and health status in young and middle-aged adults, but little is known about these relationships in older populations. We examined this issue as part of a randomized trial to determine the cost savings and changes in health-related quality of life associated with the provision and reimbursement of a preventive services package to 2,524 Medicare beneficiaries enrolled in Group Health Cooperative of Puget Sound. Baseline self-efficacy data were collected for all participants in five behavioral areas: exercise, dietary fat intake, weight control, alcohol intake, and smoking. Results reveal that efficacy and outcome expectations for these health behaviors are not independent. Correlational and factor analyses indicate two dimensions of efficacy expectations, one consisting of exercise, dietary fat, and weight control, and another consisting of smoking and alcohol consumption. Outcome expectations of the five behaviors form a single dimension. Older adults with high self-efficacy had lower health risk in all behaviors and better health. Regression analyses detected a positive association between socioeconomic status and health-related quality of life (p < .02), but the strength of the association declined (p < .11) after the self-efficacy measures entered the model, indicating that self-efficacy explains part of the association between socioeconomic status and health status. Interventions aimed at improving self-efficacy also may improve health status.

Age Factors

LiCl aversive conditioning has transitory effects on pheromonal responsiveness in male house mice (Mus domesticus).

Appetitive and aversive experiences influence whether odors elicit precopulatory behavior from male rodents. A role for aversive experience in odor-elicited reproductive behaviors had been demonstrated for hamsters and rats, but similar work on house mice had not been performed. Four experiments examined whether lithium chloride (LiCl) aversive conditioning would alter two precopulatory behaviors (ultrasonic vocalizations and olfactory preference) that male house mice normally exhibit to female urine. Lithium chloride was used to aversively condition male house mice to either female urine odor, female urine in drinking water, the female herself, or a novel odor. Independent tests of taste aversion establishment were also conducted. In these experiments, LiCl aversive conditioning produced robust taste aversions to water adulterated with either female urine or a novel odorant/tastant (isoamylacetate), but only transitory decrements in odor-elicited, male-typical precopulatory behaviors. We conclude that aversive conditioning is unlikely to be a significant factor affecting male mouse precopulatory behavior.

Animals

Cystic duct obliteration and gallbladder mucosal destruction: a feasible alternative to cholecystectomy.

'Chemical cholecystectomy' has been proposed as an alternative to removal of the gallbladder. This study assessed cystic duct obliteration using bipolar electrocoagulation (with sham cannulation controls) and gallbladder mucosal treatment with tetracycline (or saline controls) in 29 mongrel dogs. Cystic duct obstruction was assessed by tube cholecystography at day 14, and epithelial damage by histology at day 42. Electrocoagulation by duct diathermy effectively occluded the cystic duct in 14 of 19 animals; however, this was associated with mucocele formation unless mucosal treatment with tetracycline was also performed. Immediate instillation of tetracycline after duct electrocoagulation produced only partial epithelial damage. The combination of duct electrocoagulation and delayed tetracycline instillation at 14 days produced complete destruction of all gallbladder epithelium and an effective chemical cholecystectomy.

Animals

Neuropathologic findings in AIDS and human immunodeficiency virus infection--report on 30 patients.

Central nervous system findings in 30 fatal cases of human immune deficiency viral (HIV) infection are described. Twenty seven patients had acquired immune deficiency syndrome (AIDS) and three patients had serological evidence of HIV infection only (HIV seropositive). Twenty nine patients had neuropathologic abnormalities at autopsy and frequently had more than one neuropathologic process. Neurologic disease was the dominant clinical feature in nineteen patients. The spectrum of neuropathologic disease is similar to that described in other series encompassing direct HIV infection of brain; indirect CNS involvement by opportunistic pathogens differing slightly from other series in their relative frequency; lymphoma and neurovascular disease. This, the first report which serves to document the level of neurologic disease in Irish patients with AIDS and HIV infection should help to provide meaningful information for use in the planning of neurologic and rehabilitation services for these patients.

Acquired Immunodeficiency Syndrome

Piezoelectric lithotripsy and soft tissue injury. Safety limits in the experimental and clinical setting.

Controversy surrounds the capacity of extracorporeal shock wave lithotripsy to cause soft tissue injury. This study examines the influence of different dosages of shock waves on the gall bladder in both humans and an animal model. Sixty one guinea pigs were divided into groups and subjected to different numbers of shock waves (6,000, 24,000, and 48,000) at different frequencies (2.5, 5.0, 10, 20 shock waves per second) and sacrificed at different intervals. Soft tissue damage after lithotripsy seemed to be related to the number of shock waves administered. In addition, repeated administration of low dose lithotripsy (at weekly intervals for six weeks) did not seem to produce a cumulative injury. Finally, in the animals sacrificed one month after receiving high dose lithotripsy, no soft tissue damage was evident, indicating satisfactory healing. Thirty patients were subjected to either high dose (36,000 shock waves) or low dose (6,000 shock waves) lithotripsy 24 hours before elective cholecystectomy. Both macroscopic and microscopic evidence of soft tissue injury were detected in a significantly higher percentage of patients who received a high dose in a single treatment (p less than 0.05). The group who received repeated low dose lithotripsy showed no evidence of cumulative injury. We conclude that low dose lithotripsy produces minimal soft tissue injury and is safe when repeated up to six times at weekly intervals.

Animals