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Biomedical subjects

A Harrison

Publications and source records attributed to A Harrison.

At least 37 records · Page 2Linked to original sources
PubMed2000

Stress distribution associated with loaded ceramic onlay restorations with different designs of marginal preparation. An FEA study.

The design of marginal finish of an inlay or onlay could influence the prognosis of the restoration since this area is subjected to various mechanical or chemical actions during function. This study was carried out to determine the tensile stresses which develop at the marginal area when subjected to vertical and horizontal loads. Onlay restorations with three different types of marginal finish, i. e. shoulder, chamfer and bevel, were modelled in three dimensions using the finite element method, and were then subjected to vertical and horizontal load at three different sites. The results show that horizontal forces acting on the restoration generate the highest tensile stresses whilst the vertical forces generate high tensile stresses at the margins of the chamfer and bevel designs.

Bicuspid↗
PubMed2000

Assessment of plaque prevention on dentures using an experimental cleanser.

STATEMENT OF PROBLEM: Adequate plaque control is essential for the maintenance of a healthy oral mucosa. Denture cleansers are a popular method used by denture wearers for cleaning. The clinical effectiveness of a new cleanser in tablet form has not been tested in vivo. Methods used for the in vivo assessment of denture cleanser effectiveness are often not standardized. PURPOSE: The aims of this in vivo study were to develop a new method for assessing plaque levels on dentures by using digital imaging and to use this methodology, together with a validated visual scoring method, to evaluate plaque buildup on dentures. MATERIAL AND METHODS: Thirty-five subjects were randomized to 1 of 2 treatment groups: (1) dentures soaked in a new cleanser, or (2) dentures soaked in water. The treatment period lasted 14 days. Plaque was assessed at baseline and on days 2 and 14 by using digital image analysis and a visual scoring technique. Results were analyzed with ANOVA at the 95% confidence interval. RESULTS: The new cleanser showed a statistically significant reduction in mean visual plaque of 51% at day 2 (P = 0.0002) and 42% (P = 0.0014) at day 14 compared with water. Similar results were seen with digital imaging. CONCLUSION: The new denture cleanser proved to be effective at preventing plaque accumulation on dentures. The analysis of digital images gave similar results as the visual scoring method.

Adhesives↗
PubMed2000

Nosocomial transmission of tuberculosis (TB) associated with care of an infant with peritoneal TB.

Nosocomial transmission of tuberculosis (TB) after exposure to infected peritoneal fluid has not been described. We report the exposure of 111 healthcare workers to infected dialysate from an infant with TB peritonitis. Two (5%) of 39 primary-care nurses, but no doctors or environmental service workers, had apparent tuberculin skin test conversions, raising the concern that patients with peritoneal TB may be a source for nosocomial transmission of TB.

Cross Infection↗
PubMed2000

Barriers to implementing South Africa's Termination of Pregnancy Act in rural KwaZulu/Natal.

INTRODUCTION: South Africa's Termination of Pregnancy Act, the most liberal abortion law in Africa, took effect early in 1997. In spite of the anticipated benefits to women's health, however, public reaction has been mixed. In the country's most populous province, KwaZulu/Natal, opposition is strong and most health care providers have refused to provide the service. This study explored attitudes and beliefs about abortion and the Termination of Pregnancy Act among primary care nurses and community members in a rural district in order to better understand barriers to implementation of the new law. METHODS: As part of a community survey on women's reproductive health (n = 138), questions on knowledge, attitudes and beliefs about abortion were asked, as well as awareness of the provisions of the Termination of Pregnancy Act. To better understand the perspectives of health care workers, a survey among primary care nurses on duty (n = 25) was also conducted. In-depth interviews were conducted with both nurses and women in the community to further pursue issues raised in the two surveys. RESULTS: Support for the Act was low (11%) among both community members and nurses, and few supported abortion on request (18 and 6%, respectively). Within each group, however, a clear hierarchy of support was observed: a majority of nurses (56%) and community members (58%) supported abortion in the case of rape or incest, or if the continued pregnancy would endanger a woman's health (61 and 56%, respectively), but few supported abortion for social or economic reasons. In-depth interviews revealed that abortion is seen as contrary to prevailing community norms; nurses were poorly informed about the Termination of Pregnancy Act and felt confused in their professional responsibilities. CONCLUSIONS AND RECOMMENDATIONS: Legalization alone cannot ensure implementation of abortion services. In South Africa, extensive media coverage prior to passage of the law ensured almost universal awareness of the Act, but little public education took place at the same time. In spite of general opposition to the law, however, there is an encouraging level of support for abortion in some circumstances. These findings suggest that abortion services can be implemented, even in conservative rural areas, but that a process of information dissemination and community consent prior to implementation is essential. Locating abortion within broader reproductive health services could be an effective way to improve access and acceptability.

Abortion, Legal↗
PubMed2000

Oral health in Hlabisa, KwaZulu/Natal--a rural school and community based survey.

AIMS: To investigate rates of dental caries and periodontal disease, available dental services and resources and perceived needs in a rural South African community. DESIGN: A cross-sectional field study including situational analysis and focus group discussions. SETTING: KwaZulu/Natal, South Africa. PARTICIPANTS: A total of 520 children, adolescents and adults. METHODS: WHO caries scores and periodontal CPI score were determined through clinical examinations in five age groups, 5-6 years, 12 y, 15 y, 35-54 y, 55 y+. Focus groups included ten 15-year-old children and ten adults. RESULTS: Caries prevalences and (mean scores) were 5-6 y 64% (dmft 3.0), 12 y 24% (DMFT 0.4), 15 y 27% (DMFT 0.8), 35-54 69% (DFT 2.6) and 55 y+ 80% (DFT 2.7). Most caries was untreated and where present, treatment had been extraction. Dental caries rates were low and except for 5-6 y were within WHO targets for the year 2000. Periodontal disease prevalence was high but would respond to improved oral hygiene. Knowledge of oral health was rudimentary. CONCLUSIONS: A district-wide oral health promotion programme is required preceded by research to define effective health education messages. Access to simple but effective preventive and curative services would seem reasonable. In view of the lack of resources ART is suggested as caries treatment.

Adolescent↗
PubMed2000

Relation of Bcl-2 expression to androgen receptor, p21WAF1/CIP1, and cyclin D1 status in prostate cancer.

BACKGROUND: There is currently no effective treatment for recurrent hormone refractory carcinomas of the prostate gland. An understanding of the underlying mechanisms responsible for the progression of these lesions is likely to be important for the development of new therapeutic approaches. Recently, it has been suggested that the transition to a hormone independent state is accompanied by increased proliferation and bcl-2 gene expression, as well as by a decreased apoptotic state. AIM: To investigate the possible role of Bcl-2 and other cell cycle regulating proteins in the development of prostatic tumours. METHODS: Immunohistochemistry was used to study the relation between the expression of Bcl-2 and the androgen receptor, as well as p21WAF1/CIP1 (p21), and cyclin D1 status, in a series of 89 prostate cancer samples taken before androgen withdrawal treatment. RESULTS: Androgen receptor negative tumours expressed significantly higher amounts of Bcl-2 than those prostate carcinomas with low/medium androgen receptor values. However, in tumours expressing the highest amounts of androgen receptor, Bcl-2 expression was also high. A significant positive relation between Bcl-2 and p21 expression, as well as an inverse relation between Bcl-2 and cyclin D1 expression, was noted. Androgen receptor positive samples also expressed significantly higher amounts of cyclin D1. CONCLUSIONS: These results suggest that p21 and cyclin D1 expression in prostatic cancer might be modulated by Bcl-2 and by androgens and in turn this could be relevant to the progression of prostatic cancer.

Cyclin D1↗
PubMed2000

Tooth colour analysis by a new optoelectronic system.

The difficulties in assessing and comparing tooth shades are well documented. This pilot study introduces an alternative method of photoelectric tooth colour measurement, the silicon photodiode array apparatus. This apparatus was used to determine colorimetric values for samples of acrylic resin teeth and the results compared with colour values obtained using a conventional photoelectric tristimulus colorimeter. Whilst a significant difference was found between some colorimetric data produced by the two types of apparatus for the same sample these differences existed purely at the mathematical level and would not be perceived by a human observer.

Acrylic Resins↗
PubMed2000

Patient satisfaction in an emergency dental clinic.

OBJECTIVES: Attendance at emergency clinics may be accompanied by extensive waiting times and frustration and may not result in patients obtaining the treatment which they expected. The objective of the study was to ascertain patient satisfaction with the overall provision of day time emergency services in a university dental teaching hospital, for quality assurance purposes. METHODS: Patients (or persons accompanying child patients) attending the clinic, selected according to a sampling frame designed to identify approximately 10 per cent of attendees, completed a questionnaire. RESULTS: High levels of patient satisfaction were found; 17 of 24 questions scoring satisfaction on a scale 1-5 had median scores of 5, six had median scores of 4 and one had a median score of 3. The lower scores related mostly to patient facilities rather than treatment. CONCLUSIONS: Overall patient satisfaction with their dental A & E experience has been extremely positive, probably attributable to a well motivated staff using a team approach.

Adolescent↗
PubMed2000

Patterns of attendance and treatment at an emergency dental clinic: a three year follow-up.

OBJECTIVES: Patterns of attendance at the Dublin Dental Hospital's Accident and Emergency Clinic in 1996 were compared with figures from 1993 to look for changes, especially in the light of changing provision of public funding for dental treatment for medical card holders and dependants. METHODS: An audit of patient clinical records for one month in 1996 was compared to previously published data relating to 1993. RESULTS: While patient numbers were similar in the two time periods (718 in 1993 versus 708 in 1996), the proportion of attendances by medical card holders or their dependants dropped from 48 per cent to 36 per cent. The proportion of non urgent treatments had also dropped over the three years. CONCLUSIONS: Changes in the provision of publicly funded dental treatment for medical card holders and dependants has reduced the proportion of such patients attending the clinic. However, their places have been taken by other patients.

Adolescent↗
PubMed2000

The effect of continuous poly (methyl methacrylate) fibres on some properties of acrylic resin denture base material.

This study investigated the effect of continuous poly (methyl methacrylate) fibres on the transverse strength and impact strength of poly (methyl methacrylate) denture base resin. The fibres were added in three arrangements, a single unidirectional (longitudinal in the length of the specimen) layer, two longitudinal layers and in cross ply form (a combination of an inferior longitudinal layer and a superior transverse layer). The results indicated that the transverse bend and impact strengths of poly (methyl methacrylate) denture base resin, were not significantly improved by the addition of poly (methyl methacrylate) fibres.

Acrylic Resins↗
PubMed1999

Tuberculosis in immigrants and visitors.

Immigrants and visitors are a significant factor in the epidemiology of tuberculosis (TB) in New Zealand, accounting for an increasing proportion of notifications in recent years. At present screening of immigrants from countries with a high incidence of TB is inadequate. There are deficiencies in procedures, inadequate screening coverage, ineffectual coordination between the Ministry of Health and New Zealand Immigration Service, incomplete follow-up on those at risk of TB, confusion over financial responsibility, inadequate data to describe the problems and monitor interventions, and a lack of commitment to assistance with TB control in neighbouring countries from which some of our TB arises. We make recommendations in all of these areas. Timely screening of high-risk immigrants should be seen as health protection for ethnic minorities.

Emigration and Immigration↗
PubMed1999

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Explore the source record for details and available documents.

Journal Article↗
PubMed1999

Preparation of Iron Particles Coated with Silica.

A method is described for coating fine iron particles ( approximately 1 µm) with a uniform silica layer, produced by the hydrolysis of tetraethyl orthosilicate. The presence of a small amount of gelatin on the surface of the iron particles facilitates this process. X-ray photoelectron measurements indicate that the gelatin interacts with the surface of the iron particles through both nitrogen (in -NH(2) groups) and oxygen (in -COOH groups) and then binds to the silica. The silica coating increases the resistance of the iron particles to oxidation on heating in air, raising the temperature at which a detectable oxidization occurs from 330 to 400 degrees C. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Deposition of fenoterol from pressurized metered dose inhalers containing hydrofluoroalkanes.

The imaging technique of gamma scintigraphy has been used to quantify the total amount of drug deposited in the lungs and the pattern of regional lung deposition, for formulations of Berodual (Boehringer Ingelheim GmbH) delivered from pressurized metered dose inhalers formulated with chlorofluorocarbons, and with hydrofluoroalkane-134a or -227. Data were expressed as the mass of fenoterol deposited in the lungs from the Berodual formulations. All the formulations tested gave a whole lung deposition less than 20% of the metered (exvalve) dose. The mass of fenoterol deposited in the lungs for a solution formulation containing hydrofluoroalkane-134a was inversely proportional to the actuator nozzle diameter. The data suggest that the total and regional lung deposition of hydrofluoroalkane-based pressurized aerosol formulations is highly product-specific and that changes in bioavailability can be brought about by varying both the constituents of the formulation and the design of the actuator.

Female↗
PubMed1999

The reinforcement of dentures.

The material most commonly used for the fabrication of complete dentures is poly (methyl methacrylate) (PMMA). This material is not ideal in every respect and it is the combination of virtues rather than one single desirable property that accounts for its popularity and usage. Despite its popularity in satisfying aesthetic demands it is still far from ideal in fulfilling the mechanical requirements of a prosthesis. The fracture of dentures may be due to the mechanical properties of the acrylic resin or may be due to a multiplicity of factors leading to failure of the denture base material. Generally, there are three routes which have been investigated to improve the impact properties of PMMA: the search for, or development of, an alternative material to PMMA; the chemical modification of PMMA such as by the addition of a rubber graft copolymer; and the reinforcement of PMMA with other materials such as carbon fibres, glass fibres and ultra-high modulus polyethylene. The following review of attempts to improve the mechanical properties of denture base material takes account of papers published during the last 30 years.

Carbon↗
PubMed1999

STD syndrome packets: improving syndromic management of sexually transmitted diseases in developing countries.

OBJECTIVE: To design, introduce, and evaluate "STD syndrome packets" containing recommended drugs for each syndrome, four condoms, a partner treatment card, and a patient information leaflet, with the goal of improving sexually transmitted disease (STD) case management. METHODS: Packet design evolved around available packaging technology, informed by pilot testing with nurses working in primary care clinics, doctors in private medical practices, and patients with an STD, in Hlabisa, South Africa. Evaluation 1 year later included analysis of distribution records and interviews with 16 nurses and 64 patients. RESULTS: A cheap packet (2 U. S. cents each, excluding contents) compatible with current legislation was designed and introduced to six public sector clinics and as a short pilot to five private medical practices. Four thousand eighty-five packets were distributed to the clinics, equivalent to approximately 115% of the STDs reported over that period. All 16 nurses reported using the packets, but only 63% did so all the time because of occasional supply problems. All believed the packets improved treatment by saving time (75%), improving supply of condoms and partner cards (44%), and making treatment easier (56%). Patients also responded positively, and most said they would buy a packet (up to $5) at a pharmacy (84%) or store (63%) if available. CONCLUSIONS: The STD syndrome packets have the potential to improve STD syndromic management by standardizing therapy and improving the supply of condoms, partner cards, and information leaflets. Packets are popular with practitioners and patients, but consistent supply is essential for maximal impact. There may be scope for social marketing of the packets, which could further increase use.

Anti-Infective Agents↗