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Biomedical subjects

A Harrison

Publications and source records attributed to A Harrison.

At least 91 records · Page 5Linked to original sources
PubMed1997

Can the NHS cope in future?

Four potential pressures are likely to determine whether the NHS will be able to cope in future: the change in population structure, changes in level of morbidity, introduction of new technologies, and increasing expectations of patients and NHS providers. New technology and changes in expectations are likely to have the biggest effect and are also the most difficult to quantify. Nevertheless, these pressures are to some extent amenable to control. If the growth in funding continues as it has in the past there is no convincing evidence that the NHS will not continue to cope.

Attitude of Health Personnel↗
PubMed1997

Funding the NHS. Is the NHS underfunded?

Since 1948 there has been constant debate over whether the NHS is underfunded. The debate heats up when crises in the NHS hit the headlines as occurred last year. Various groups, of all shades of the political spectrum, have argued that the NHS is unsustainable with current funding increases because of demands from demographic change, new technology, and increasing expectations. The government is almost a lone voice in arguing that the NHS is sustainable but may not be doing enough to ensure that it remains so in future. This article examines seven broad approaches used to support the case that the NHS is underfunded and concludes that all have flaws. There is no satisfactory answer to the question of whether the NHS is underfunded because the answer requires value judgments that will inevitably give rise to disagreements.

Attitude to Health↗
PubMed1997

The effect of untreated UHMWPE beads on some properties of acrylic resin denture base material.

OBJECTIVES: To evaluate the effect of surface untreated ultra high molecular weight polyethylene (UHMWPE) beads on a range of properties of the polymerised acrylic resin denture base material. METHODS: UHMWPE in the form of surface untreated beads was added to acrylic resin denture base material in various percentages (2.5%, 5%, 7.5% and 10%) to form a composite material. The influence on doughing and manipulation times, transverse and impact strength and hardness characteristics were examined. RESULTS: The results indicated that the manipulation and setting times gradually increased as the percentage of UHMWPE beads in the acrylic resin powder increased. By increasing the percentage of incorporated UHMWPE beads, there was a decrease in modulus of rupture and impact fracture resistance. There was also an effect on the hardness with an increasing percentage of beads lowering the hardness value, although this was not consistent. CONCLUSION: It was concluded that the use of untreated UHMWPE beads is of no significant benefit to the properties of acrylic resin.

Acrylic Resins↗
PubMed1997

The effect of filler content and processing variables on dimensional accuracy of experimental composite inlay material.

STATEMENT OF PROBLEM: Dimensional accuracy of a composite inlay restoration is important to ensure an accurate fit and to minimize cementation stresses. PURPOSE OF STUDY: A method was developed to measure dimensional accuracy and stability of a composite inlay. MATERIAL AND METHODS: A standard Class II (MOD) inlay cavity stainless steel mold was made with six circular indentations placed on the occlusal floor of the cavity and four indentations on each gingival floor to act as datum points in the measurement of linear polymerization shrinkage. The inlay restorations were prepared from an inlay-onlay composite material of different filler contents (50%, 65%, and 79% by weight). For each filler content group, three curing methods were used: light curing only, light curing and heat curing at 100 degrees C for 5 minutes, and light curing and heat curing at 100 degrees C for 5 minutes and then storage in distilled water for 7 days. The accuracy of the MOD inlays was determined by measuring the shrinkage of the restoration on the occlusal floor areas and the gingival seats. RESULTS: The results demonstrated an inverse linear relationship between filler content and polymerization shrinkage. There was a tendency for the light-curing and heat-curing method to show an increase in polymerization shrinkage. An expansion was recorded between the mesial and distal boxes when the specimens were soaked in water for 7 days. CONCLUSIONS: This study suggested that the inlay mold limits the physical shrinkage that can occur between the mesial and distal axial walls of the inlay restoration because the inlay cannot shrink to a smaller dimension than the mold. Water sorption then causes hygroscopic expansion, which enlarges the distance between the mesial and distal walls.

Analysis of Variance↗
PubMed1997

Neoadjuvant androgen ablation prior to radiotherapy for prostate cancer: reducing the potential morbidity of therapy.

OBJECTIVES: To determine the impact of neoadjuvant hormonal therapy (NHT) prior to conformal radiotherapy on the reduction of volume of normal tissue structures exposed to high doses of radiation therapy and to evaluate the overall late toxicity and response to treatment among patients treated with this approach. METHODS: Among 214 patients treated with neoadjuvant leuprolide acetate and flutamide for 3 months prior to three-dimensional conformal radiotherapy (3D-CRT), 45 patients were prospectively evaluated with detailed dose-volume histogram (DVH) analyses to determine the extent of improvement of the geometry of the target volume after NHT. All patients underwent simulation and conformal treatment planning before and after NHT, and the pre- and posthormone DVH calculations for all normal tissue structures were compared for each patient. In addition, toxicity and response to therapy were evaluated in the 214 patients treated with this combined approach. RESULTS: In the 45 patients evaluated, the median reduction of the rectal and bladder volumes receiving 95% of the prescription dose (D95) were 18% and 46%, respectively, while 91% showed a reduction of small bowel volume in a range of 27% to 100% of the prehormonal values. Among the entire group of 214 patients treated with NHT and 3D-CRT, no grade 3 or 4 toxicity was observed with a median follow-up of 15 months after 3D-CRT. The 3-year actuarial grade 2 late gastrointestinal and genitourinary toxicity rates were 6% and 18%, respectively. CONCLUSIONS: Neoadjuvant hormonal therapy effectively reduces the volume of normal tissue exposed to high radiation doses in the majority of treated patients and decreases the potential morbidity of therapy.

Aged↗
PubMed1997

Selective activation of the external oblique musculature during axial torque production.

OBJECTIVE: To investigate whether different geographical regions of the external oblique musculature can activate at different levels and, if they do, to quantify the magnitude of these differences as a function of postural parameters during twisting exertions. DESIGN: Repeated measures design using electromyography on healthy subjects. BACKGROUND: The majority of the models currently used to assess spinal loading have represented the trunk musculature using single force vectors connecting a muscle's point of origin to its point of insertion. However, for muscles with large areas of origin and/or insertion (such as the external obliques), this single vector modelling approach misrepresents the multiple vector reality which, in turn, underestimates the complex loads these muscles can develop. METHODS: Nine subjects performed sub-maximal isometric axial twisting exertions (20, 40 and 60% of maximum voluntary contraction) while assuming six different postures defined by three levels of axial rotation (-20 degrees, 0 degrees and 20 degrees ) and two levels of sagittal flexion (0 degrees and 20 degrees ). As the subjects performed these isometric exertions, the integrated electromyographic activity was sampled using surface electrodes at five different locations over the right and the left external oblique muscles. RESULTS: The results showed significant (p<0.05) regional differences in the activation profiles and these activation profiles changed as a function of trunk posture. CONCLUSIONS: The external oblique musculature is capable of differential activation and the activation profiles of the different regions are affected by the posture of the torso. RELEVANCE: These findings suggest that the external oblique muscle is capable of selective activation of different regions along its cross-section and should, therefore, be modelled using multiple vectors. The result can have a direct bearing on the calculated spine loading, especially lateral and anterior/posterior shear forces.

Journal Article↗
PubMed1997

An evaluation of self-cured and visible light-cured denture base materials when used as a denture base repair material.

The aim of this study was to compare some of the physical properties of a heat-cured, a self-cured and a visible light-cured acrylic resin, and to evaluate the suitability of visible light-cured resin as a repair material for dentures made of heat-cured acrylic resin. Transverse strength, surface hardness and impact strength were determined for the three materials and the efficiencies of light-cured and self-cured resins, when used as a repair material, were evaluated by testing the transverse strength of repaired heat-cured specimens 1 hour, 1 week and 1 month after repair. The results showed that the rigidity of specimens repaired with light-cured resin improved with longer water storage. However, their transverse strength reached a maximum after one day and was reduced after 1 month. The rigidity and transverse strength of specimens repaired with self-cured resin were not influenced significantly by water storage and the transverse strength was significantly higher than the light-cured repaired specimens.

Acrylic Resins↗
PubMed1997

The optimum curing cycle for a light- and heat-cured composite inlay material.

The transverse bend test and surface microhardness test were used to determine the optimum curing cycle for a light- and heat-cured composite inlay material. Specimens were light-cured (control) and light- and heat-cured using the following temperatures: 50 degrees C for 5 min; 50 degrees C for 10 min; 100 degrees C for 1 min; 100 degrees C for 5 min; 100 degrees C for 10 min; and 100 degrees C for 15 min. Heat-curing in boiling water at 100 degrees C for at least 1 min significantly improved the transverse strength, modulus of elasticity and surface microhardness compared to light-curing only or at 50 degrees C. The curing cycle of 100 degrees C for 5 min is considered the most appropriate.

Analysis of Variance↗
PubMed1997

Should doctors inform terminally ill patients? The opinions of nationals and doctors in the United Arab Emirates.

OBJECTIVES: To study the opinions of nationals (Emiratis) and doctors practising in the United Arab Emirates (UAE) with regard to informing terminally ill patients. DESIGN: Structured questionnaires administered during January 1995. SETTING: The UAE, a federation of small, rich, developing Arabian Gulf states. PARTICIPANTS: Convenience samples of 100 Emiratis (minimum age 15 years) and of 50 doctors practising in government hospitals and clinics. RESULTS: Doctors emerged as consistently less in favour of informing than the Emiratis were, whether the patient was described as almost certain to die during the next six months or as having a 50% chance of surviving, and even when it was specified that the patient was requesting information. In the latter situation, a third of doctors maintained that the patient should not be told. Increasing survival odds reduced the number of doctors selecting to inform; but it had no significant impact on Emiratis' choices. When Emiratis were asked whether they would personally want to be informed if they had only a short time to live, less than half responded in the way they had done to the in principle question. CONCLUSIONS: The doctors' responses are of concern because of the lack of reference to ethical principles or dilemmas, the disregard of patients' wishes and dependency on survival odds. The heterogeneity of Emiratis' responses calls into question the usefulness of invoking norms to explain inter-society differences. In the current study, people's in principle choices did not provide a useful guide to how they said they would personally wish to be treated.

Adolescent↗
PubMed1997

Family planning services in developing countries: an opportunity to treat asymptomatic and unrecognised genital tract infections?

OBJECTIVE: To determine the prevalence of asymptomatic and unrecognised genital tract infections among women attending a family planning clinic in rural South Africa. METHODS: 189 consecutive women had genital samples taken to diagnose infection with Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Candida albicans, Treponema pallidum, and HIV, and to diagnose bacterial vaginosis. RESULTS: Mean age was 25 years; 155 (82%) were unmarried, 156 (83%) were currently using contraception, and 41 (22%) reported having an STD treated in the preceding 12 months. Although none volunteered abnormal urogenital symptoms, 74 (39%) had at least one elicited by direct questioning. 119 women (63%) had at least one genital infection: N gonorrhoeae (eight; 4%), C trachomatis (14; 8%), T vaginalis (26; 14%), C albicans (56; 30%), active syphilis (15; 8%), HIV (44; 24%), and bacterial vaginosis (29; 15%). 49 women (26%) had multiple infections. Most infections (71; 60%) were asymptomatic. Symptomatic women failed to recognise and report their symptoms, and routine services failed to detect the infections. CONCLUSION: Prevalence of genital tract infection is high among these women, most infections are asymptomatic, and symptomatic infections are frequently not recognised. Women attending family planning clinics in such settings should be screened for syphilis and offered testing for HIV infection. Strategies to detect and treat other genital infections need to be developed.

Adult↗
PubMed1997

A novel image cytometric method for quantitation of immunohistochemical staining of cytoplasmic antigens.

Evaluation of molecular markers by immunohistochemical labelling of tissue sections has traditionally been performed by qualitative assessment by trained pathologists. For those markers with a staining component present outside of the nucleus, there has been no image histometric method available to reliably and consistently define cell interfaces within the tissue. We present a new method of approximating cellular boundaries to define cellular regions within which quantitative measurements of staining intensity may be made. The method is based upon Voronoi tessellation of a defined region of interest (ROI), and requires only the position of the nuclear centroids within the ROI. Here we describe the VORSTAIN software which has been developed based on the Oncometrics CytoSavant Automated Image Cytometry System. To demonstrate this technique, human breast cancer sections immunohistochemically stained for bcl-2 protein and counter-stained with nuclear methyl green stain were evaluated. Intra-observer variation in the measured values was between 1.5-2.6% and inter-observer variation was between 1.8-4.4%. The primary source of variability was due to difficulties in interpreting the exact position of the nuclear centroids. Analysis of mean staining densities for each slide correlated well with subjective scoring performed by two independent pathologists. Using VORSTAIN, significant variation of staining intensities between regions within the same slide was measured for some sections, indicating a large degree of heterogeneity within the tumours. The ability to accurately quantitate the degree of heterogeneity of molecular marker expression within tumours may be a valuable tool in prognostication.

Biomarkers, Tumor↗
PubMed1997

Exploring partner communication and patterns of sexual networking: qualitative research to improve management of sexually transmitted diseases.

This ethnographic research among rural South African men and women seeking care for STDs explores constraints to communication among partners and defines predominant patterns of sexual networking. A series of fifteen open-ended interviews explored topics related to sexual networking and partner communication. Patterns of sexual networking showed clear gender variation, with men more likely to discuss multiple partners. Both men and women believed they should tell one partner about their STD, most often a steady partner. Strong distinctions were made between regular and casual partners, with an emphasis on the role of trust in a steady relationship. Men and women expressed anxiety about telling their partners of their illness, but women more often expressed fear whereas men felt embarrassed. Multi-partnered sexuality is common and is widely accepted for men. While the importance of regular partnerships is clear for both men and women, sexual relationships appear to be highly unstable. Communication among partners could be facilitated by stronger health promotion messages, such as the importance of telling a partner about an STD. Prevailing patterns of communication and sexual networking have profound implications for the STD epidemic.

Adult↗
PubMed1997

An in vitro investigation of the abrasive qualities of a selection of denture-cleaning pastes on poly(methyl methacrylate) denture base material.

This study investigated the damage to poly(methyl methacrylate) (PMMA) denture base material caused by brushing with a range of denture-cleaning pastes using an electric, motor-driven, reciprocal-action toothbrushing machine. Plate specimens of PMMA were exposed to 5000, 10,000 and 20,000 brush strokes with four commercial and one recently developed denture-cleaning pastes. Products were applied as slurries in dilutions of 1:2, 1:3 and 1:5. Wear and roughness measurements were made using a surfometer. Results of a one-way analysis of variance showed that there was a statistically significant difference between each of the different denture-cleaning pastes at each given dilution for each number of wear cycles. For the denture-cleaning pastes, doubling the number of brush strokes in most cases, increased the depth of abrasion by a factor of two. A reduction in the Roughness Index and depth of wear was seen, again in most cases, with a dilution from 1:2, 1:3 and to 1:5. A recently developed paste (Blend-a-Dent Hygienic denture paste) bad a comparatively low wear and roughening effect on PMMA denture base material; however, further investigation of its stain-removal properties are necessary before it can be recommended as a suitable denture-cleaning paste.

Analysis of Variance↗
PubMed1997

The effect of surface treated UHMWPE beads on some properties of acrylic resin denture base material.

UHMWPE in the form of experimental surface treated beads was added to acrylic resin denture base material in various percentages to form a composite material. The influence on doughing and manipulation times, and transverse and impact strength was examined. The results indicated that the manipulation times, were not significantly affected as the percentage of UHMWPE beads in the acrylic resin powder increased. Increasing the percentage of incorporated UHMWPE beads resulted in an inconsistent decrease in the modulus of rupture and no effect on the impact fracture resistance. It was concluded that the use of treated UHMWPE beads is of no significant benefit to the properties of acrylic resin.

Acrylic Resins↗