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Biomedical subjects

A D Wilson

Publications and source records attributed to A D Wilson.

At least 109 records · Page 6Linked to original sources
PubMed1986

Responses of intraepithelial lymphocytes to T-cell mitogens: a comparison between murine and porcine responses.

Intraepithelial lymphocytes (IEL) were isolated from the small intestine of pigs. They showed a strong blastogenic response to the T-cell mitogens phytohaemagglutinin A (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM); in contrast, mouse IEL responded weakly to these mitogens. The response of pig IEL was age-dependent, reaching adult levels by 9 weeks of age. Early weaning of pigs delayed the onset of this response. The effects of inflammatory mediators on the response of mouse IEL were also examined.

Aging↗
PubMed1985

Consultation length: general practitioners' attitudes and practices.

A survey by postal questionnaire of 190 Nottingham general practitioners on consultation length was conducted and a response rate of 82% achieved. Reported consultation length was associated with the doctor's gender, use of an appointment system, membership of the Royal College of General Practitioners, and the number of patients seen during an average surgery. Seventy two per cent of respondents would have liked to have offered longer consultations and most thought that longer consultations would result in a higher standard of care and a lower prescription rate.

Appointments and Schedules↗
PubMed1985

The dissolution mechanisms of silicate and glass-ionomer dental cements.

The mechanism of dissolution of two dental cements of the acid-base setting types (silicate and glass-ionomer) is considered. Dissolution is incongruent, probably because most of the leached species can derive both from the matrix (polysalt gel) and the partly reacted glass particles. The release occurs by means of three discrete mechanisms, surface wash-off, diffusion through pores and cracks or diffusion through the bulk. Such behaviour is shown to be capable of being modelled with extremely high goodness-of-fit values, using equations such as y = const + at1/2 + bt. Analogies with research from the fields of geochemistry and nuclear fuel storage are made and these systems obey similar relationships. The dental cement systems differ, however, in that their dissolution is to some extent reversible. This is explained in terms of formation of insoluble complexes, either by reaction of the constituent ions, or by replacement of OH-, for example, with F-.

Chemical Phenomena↗
PubMed1985

The release of fluoride and other chemical species from a glass-ionomer cement.

The elution of fluoride, sodium and silica from a glass-ionomer cement was studied for 598 days. It was found that these species were still being released when the experiments were concluded, however, the rate of release was much diminished. The release of fluoride, sodium and silica was incongruent. Only fluoride associated with sodium appeared to be available for release.

Dental Cements↗
PubMed1985

An infant fatality following verapamil therapy for supraventricular tachycardia: cardiovascular collapse following intravenous verapamil.

A four-month-old infant with myocarditis and supraventricular tachycardia was given intravenous verapamil (0.1 mg/kg). Immediately following the dosage, the patient developed cardiovascular collapse. Aggressive, appropriate cardiopulmonary resuscitative efforts--including ventricular pacing--failed to reverse verapamil-induced decompensation. Myocarditis may have been responsible for our failure to resuscitate this infant successfully. To our knowledge, this is the first reported pediatric fatality following intravenous verapamil. We suggest that proven or suspected myocarditis should be added to the list of contraindications for intravenous verapamil therapy.

Humans↗
PubMed1985

Reaction cements as materials for the sustained release of trace elements into the digestive tract of cattle and sheep. I. Copper release.

Acid-base reaction cements were produced by reacting copper oxide with phosphoric acid. When placed in the reticulo-rumen of cattle and sheep these cements released copper into the digestive tract for at least 3 months at a rate sufficient to provide the animals' requirements for copper. Lambs given a pellet of cement at 3 months of age had significantly greater concentrations of copper in their livers than similar untreated animals when slaughtered 3-4 months later. It was shown that salts of cobalt and selenium could be incorporated into the cement to provide additional supplementation with these two elements.

Animals↗
PubMed1984

Acute illness in infants: a general practice study.

The character and frequency of acute illness in infants presenting to a general practice over a 16-week period was studied. Symptoms were classified as 'major' or 'minor' in accordance with the definitions used in a multicentre study in infant mortality.Of the 126 consultations reviewed, 106 (84 per cent) included at least one major symptom. None of the illnesses resulted in hospital admission or had a fatal outcome. It was concluded that this classification of symptoms into ;major' and ;minor' categories is not sufficiently discriminating to use in general practice. More specific definitions are required.

Acute Disease↗
PubMed1983

Mechanism of adhesion of polyelectrolyte cements to hydroxyapatite.

The interaction between polyacrylate ions and hydroxyapatite was examined using extraction techniques and infra-red spectroscopy. These studies have shown that polyacrylate ions become irreversibly attached to the surface of hydroxyapatite by displacing existing phosphate ions. The mechanism is not one of simple ion exchange, since calcium ions are displaced by the phosphate ions.

Acrylic Resins↗
PubMed1983

The cement-forming properties of phytic acid.

The properties of aluminosilicate-phytic acid cements were investigated. They proved to be fast-setting and resistant to acid attack, with the ability to bond to enamel, but not to dentin.

Adhesiveness↗
PubMed1982

NMR spectroscopy of dental materials. I. 31P studies on phosphate-bonded cement liquids.

Phosphorus-31 nuclear magnetic resonance spectroscopy of phosphoric acid solutions containing zinc and aluminium indicates that zinc forms simple salts in solution, whereas aluminium forms a number of complexes, some of which are polymeric. The formation of the aluminophosphoric acid complexes controls the gelation and strengthening of the dental silicate cement and prevents the formation of crystalline zinc phosphate in the zinc phosphate cement.

Aluminum↗
PubMed1982

The nature of the zinc polycarboxylate cement matrix.

The matrix of a stoichiometric zinc polycarboxylate cement has been shown to be identical with zinc polycarboxylate salt, which consists principally of neutralized carboxylate, groups with a few free acid groups. When excess zinc oxide is present, as in practical cements, there are no free acid groups present. There is no evidence for the formation of a chelate. Both salt and cement matrices are amorphous. The formation of the salt appears to control time-dependent changes in the consistency of the cement pastes.

Dental Cements↗
PubMed1982

Zinc oxide eugenol cements. VI. Effect of zinc oxide type on the setting reactions.

The particle size and adsorbed water on zinc oxide from various sources have been investigated and related to the reactivity with eugenol. The reactivity of zinc oxide with eugenol alone increases with the amount of water reversibly adsorbed. When 1% acetic acid is added to eugenol, the reactivity increases as the particle size of the oxide decreases. Generally, zinc oxide powders are deactivated by heat treatment because of coalescence of particles and loss of the ability to readsorb water.

Adsorption↗