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Biomedical subjects

J A Scott

Publications and source records attributed to J A Scott.

At least 19 recordsLinked to original sources
PubMed1992

The plane of fracture and shear bond strength of three composite inlay systems.

Composite inlays have been introduced to overcome some of the problems encountered with direct placement techniques. However, some doubt has been expressed about the strength of the bond between the inlay surface and the composite luting cement due to the decreased number of C = C bonds remaining following supercuring of the inlay. This study investigated the bond strength of three composite inlay systems to etched bovine enamel and recorded the plane of fracture of the samples. The bond strength of one system was significantly greater than that of the other groups and was increased by the application of an unfilled resin enamel bonding agent. Unfilled resin application did not significantly alter the other systems tested. In only one of the systems tested was the inlay/composite cement bond found to be the weak link in the bonding procedure. In this group, the application of the manufacturer's specially formulated bond enhancer did not lead to an increase in bond strength.

Acrylates↗
PubMed1992

Meteorologic influences on the frequency of pulmonary embolism.

RATIONALE AND OBJECTIVES: Reports published earlier this century suggested that meteorologic factors influence the incidence of pulmonary embolism. These observations were based on few patients and often lacked rigorous standards of evidence. In the current study, the authors evaluate the association between barometric pressure changes and pulmonary embolism using radionuclide ventilation-perfusion (V/Q) scan data. METHODS: Daily interpretation data for V/Q lung scans were correlated retrospectively with daily local barometric pressure changes over a 7-year period. RESULTS: The incidence of pulmonary embolic disease was significantly related to a decrease in barometric pressure during the 3 days preceding clinical presentation. CONCLUSIONS: Meteorologic factors are less important than better-known risk factors for pulmonary embolism; however, their effect is demonstrable in a large data sample. This work confirms previously published associations between barometric pressure changes and the incidence of pulmonary embolism.

Analysis of Variance↗
PubMed1992

Microleakage of a composite inlay system.

This study investigated the marginal seal of resin composite inlays in dentin and enamel when either unfilled resin or a second or third generation dentin bonding agent is used. Standardized mesial and distal inlay cavities were cut in 135 human third molar teeth. The teeth were randomly divided into 9 groups and inlays fabricated in a hybrid resin composite inlay material. Each group of teeth was then treated with one of 8 dentin bonding agents or an unfilled resin and cemented with a dual curing resin cement. Each group was stored in deionized water for 1 week, thermocycled between 5 degrees C, 37 degrees C and 55 degrees C for 500 cycles, then placed in 2% methylene blue solution for 15 hours. Following this the teeth were sectioned and scored for the degree of leakage observed. Marginal microleakage was minimal at enamel margins, however there was marked leakage, even when a dentin bonding agent was used, on the dentin side. Only two dentin bonding agents proved more effective than unfilled resin and in only one case was the leakage not significantly worse than in enamel.

Analysis of Variance↗
PubMed1992

Anatomic divisions.

Explore the source record for details and available documents.

Acupuncture Points↗
PubMed1991

Silane effects on luting resin bond to a Ni-Cr alloy.

This study investigates the effect of a silane coupling agent on the shear bond strength of four commercially available resin luting systems (two of which rely on mechanical retention and two which have a chemical bond to metal) when bonding a prepared Ni-Cr alloy to etched bovine enamel. Silane application reduced the bond strengths of the two chemically adhesive resins and increased the bond strength of one of the mechanically retained resins. For the other mechanically retained resin, silane application did not significantly increase the bond strength but the plane of fracture changed from resin/metal to resin/enamel: from this an increase in metal resin bond strength can be inferred.

Acid Etching, Dental↗
PubMed1991

Nutrition education in supermarkets: the Lifestyle 2000 experience.

A 15-week supermarket-based nutrition education program was conducted as part of a larger multiple-strategy community-wide health promotion project. The program consisted of point-of-purchase materials displayed in the supermarkets and was supported by a mass media campaign and promotional activities such as competitions, taste testing and cooking demonstrations. The objective of the program was to promote the selection and purchase of low-fat foods, specifically low-fat dairy products, fresh fruit and vegetables, bread and cereal products. Awareness of the promotion was high, with some self-reported behaviour change. Supermarkets are potential sites for public health nutrition education and recommendations are made for improving the effectiveness of point-of-purchase promotions.

Australia↗
PubMed1991

Diagnosing multiple parasitic infections: trypanosomiasis, loiasis and schistosomiasis in a single case.

A case is reported of a 32-year-old traveller with loiasis, schistosomiasis and African trypanosomiasis. The patient had been working in oil exploration in Nigeria and Gabon and presented with Calabar swellings and carpal tunnel syndrome. Serology for all 3 diseases was positive but microfilariae of Loa loa and ova of schistosomiasis were not found. Treatment with diethylcarbamazine and praziquantel was given for loiasis and schistosomiasis respectively. Trypanosomes were isolated from a lymph node aspirate only after repetition of the procedure 2 months later and the patient was treated with suramin. He developed a drug induced nephritis and was then treated successfully with alpha-difluoromethylornithine. There is a discussion of the difficulties encountered making these diagnoses in Europeans particularly where there are atypical clinical features. The risks of rural work in West Africa are noted and the importance of considering all parasitic diseases relevant to the travel/occupational history is emphasised.

Adult↗
PubMed1991

Retrograde suction decompression of an ophthalmic artery aneurysm using balloon occlusion. Technical note.

A large ophthalmic artery aneurysm was ligated using a modification of the retrograde suction technique described by Batjer and Samson. Temporary proximal occlusion of the internal carotid artery was accomplished with a double-lumen balloon catheter, and distal occlusion was performed with a temporary clip. The aneurysm was collapsed by gentle aspiration through the distal lumen of the balloon catheter. This greatly facilitated dissection and clip ligation of the aneurysm.

Adult↗
PubMed1991

The effect of silane on shear bond strengths of etched cast metal restorations.

This study investigated the effect of a silane on the shear bond strength between an electrolytically etched Ni-Cr alloy and bovine enamel. The effect of time delay after etching and after silaning was also investigated. The results showed there to be a significant increase in bond strength when silane was used and bonding carried out immediately following silaning. However, a delay in bonding of even one hour after silaning significantly reduced bond strength. For periods up to one week, delay in silaning after etching had no effect on bond strength.

Animals↗
PubMed1990

Sites of cadmium uptake in bacteria used for biosorption.

Electron microscopy and x-ray spectroscopy were used to determine location and type of cadmium biosorption on and in bacteria, some of which produced extracellular polymers. Examined Arthrobacter and Pseudomonas species appear to have detoxification systems that precipitate cadmium internally irrespective of whether or not they excrete polymers. Capsular Klebsiella aerogenes strains showed minimal intracellular uptake but over a 5-100 mg dm-3 Cd range produced the highest net metal removal levels due to significant extracellular adsorption.

Arthrobacter↗
PubMed1990

Negative scintigraphy with positive magnetic resonance imaging in bone metastases.

We report three patients with known primary tumor in whom radionuclide skeletal imaging for metastatic disease was normal with or without clinical symptomatology referable to this area. Magnetic resonance imaging (MRI) of the spine demonstrated focal areas of abnormal signal intensity in the vertebral bodies of these patients. In all three patients, biopsy confirmed metastatic disease. All the patients received radiation or chemotherapy depending upon the etiology. These preliminary data suggest that MR imaging may be useful in evaluating patients with known primary tumor in whom clinical suspicion persists despite a negative radionuclide bone scan.

Bone Marrow↗
PubMed1990

Cardiovascular changes after bone marrow transplantation in dogs with mucopolysaccharidosis I.

Five dogs with mucopolysaccharidosis I, 3 of which had been treated with bone marrow transplantation (BMT), were evaluated for 20 months with electrocardiography, thoracic radiography, and M-mode and 2-dimensional echocardiography. Treated and untreated (control) dogs had widened P waves on ECG. Thoracic radiographs remained normal for all dogs throughout the study. Thickening of the mitral valve was observed on echocardiograms of dogs in both groups, but the untreated dogs appeared to have thicker valves. Concentrations of glycosaminoglycans in the mitral valves and myocardium were higher in control dogs than in treated dogs. Markedly large aortic root diameters were observed on echocardiograms in both untreated dogs, but aortic root diameters remained normal in treated dogs. Echocardiography, but not electrocardiography, was useful in monitoring heart enlargement in each dog. Dogs treated with BMT generally had less severe cardiac changes and slower disease progression than control dogs.

Animals↗
PubMed1990

Report of the 1989 Asilomar meeting on education in genetic counseling.

In September, 1989, 35 individuals representing training programs for genetic counselors and genetic nurse specialists, the Education Committee of the National Society of Genetic Counselors (NSGC), and others with interest and expertise in genetic counselor education met at Asilomar, CA. The purpose of this meeting was to reevaluate training program curricula, both didactic and experiential; to discuss the need for and desirability of advanced graduate education in genetic counseling; and to consider whether alternatives to master's-level training are needed to overcome a growing manpower shortage in the provision of genetics services. This article summarizes recommendations for master's-level training curricula, reviews options and implications for post-master's genetic counselor education, and examines issues related to training for people without a master's degree who also provide patient and community genetics education.

Education, Graduate↗
PubMed1989

The role of beneficence in clinical genetics: non-directive counseling reconsidered.

The popular view of non-directive genetic counseling limits the counselor's role to providing information to clients and assisting families in making decisions in a morally neutral fashion. This view of non-directive genetic counseling is shown to be incomplete. A fuller understanding of what it means to respect autonomy shows that merely respecting client choices does not exhaust the duty. Moreover, the genetic counselor/client relationship should also be governed by the counselor's commitment to the principle of beneficence. When non-directive counseling is reexamined in light of both these principles, it becomes clear that there are cases in which counselors should attempt to persuade clients to reconsider their decisions. Such attempts are consistent with non-directive counseling because, while respecting the clients' decision-making authority, they insure that clients act with full knowledge of the moral consequences of their decisions.

Beneficence↗
PubMed1989

Morphologic and functional correlates of plasma membrane injury during oxidant exposure.

Plasma membrane injury by exposure to hydrogen peroxide was examined in a renal epithelial cell line (LLC-PK1). Morphologic and functional parameters of plasma membrane integrity were studied in an attempt to eludicate the sequence of membrane alterations during the evolution of hydrogen peroxide-mediated injury. These parameters included plasma membrane potential and permeability, plasma membrane bleb formation, cellular size, and plating efficiency. Plasma membrane potential was the earliest parameter affected by hydrogen peroxide exposure. Half maximal depolarization occurred within 15-30 min of exposure to 1 mM, after 10-15 min exposure to 100 mM and after over 150 min exposure to 10 microM hydrogen peroxide. After exposure to 1 mM hydrogen peroxide, the following sequence of events was seen; increased plasma membrane blebbing (30 min), cell swelling (90-125 min) and increased plasma membrane permeability (150-240 min). After a 30 min exposure to 1 mM hydrogen peroxide, cellular plating efficiency, measured at 24 h, was reduced by 50% (P less than .001). These changes were accelerated, although their order of appearance was unchanged, at higher concentrations of hydrogen peroxide. We conclude that functional and morphologic expressions of cellular injury in this model occur in a defined sequence with plasma membrane depolarization representing the earliest marker of membrane injury during hydrogen peroxide exposure.

Animals↗