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Biomedical subjects

K W Stephen

Publications and source records attributed to K W Stephen.

At least 127 records · Page 7Linked to original sources
PubMed1977

Phenytoin concentrations in mixed, parotid and submandibular saliva and serum measured by radioimmunoassay.

1 Concentrations of phenytoin in mixed, parotid and submandibular saliva and serum were determined in normal subjects after an oral dose, using a specific double antibody radioimmunoassay which requires only 20 micronl fluid. 2 Semi-log concentration-time plots of phenytoin concentration in mixed saliva and serum gave good parallelism after the initial 14 h post-administration period. 3 The mean ratio of the mixed saliva: serum phenytoin concentration was 10.3% +/- 1.5 (s.d.) in seven normal subjects. 4 Phenytoin concentrations found in separate parotid and submandibular salivary fractions did not differ but were significantly greater (P less than 0.001) than those found in mixed saliva. 5 Phenytoin concentrations in all salivary fractions were independent of the volume of fluid produced and the degree of stimulation. 6 The rate of phenytoin secretion in the parotid and submandibular fluid was proportional to the salivary flow rate. 7 These data suggest that mixed saliva may be a suitable medium for the monitoring of phenytoin concentrations and may provide a non-invasive alternative to the direct determination of phenytoin in serum.

Adult↗
PubMed1977

The performance of ultraviolet lights used to polymerize fissure sealants.

The performances of ultraviolet (uv) lights used to initiate polymerization in fissure sealant systems were studied with a view to establishing recommendations for improving clinical results. The relationship between the setting time of an uv polymerized sealant (Nuva-seal) and the intensity of radiation applied was first established. This was compared with the intensity and distribution of radiation from seven Nuva-lites and one Quartzlite. It was found that some of the Nuva-lites did not produce an average intensity of uv radiation sufficient to completely polymerize Nuva-seal within the manufacturer's recommended exposure times. It is suggested that this may be a factor contributing to the large variation in sealant retention found in the different clinical trials with Nuva-seal. Finally, a number of recommendations are made to ensure that sufficient uv radiation is applied to all sealant surfaces when the Nuva-seal system is used.

Dental Equipment↗
PubMed1977

The erupting first permanent molar--its place in stratified clinical field studies.

Erupting first permanent molars of 5 1/2 to 6 1/2 year-olds are eminently suited for the clinical testing of potential caries-inhibiting techniques. Due to the rapid onset of caries in these teeth, accurate monitoring of new materials/regimes can be instituted and meaningful data obtained within one year of trial commencement. In addition, by concentrating on this age-group and by also stratifying for socio-economic status, deciduous caries experience and three-month wide age-bands, different trials' data can be readily compared. A further benefit is that these most caries-prone teeth can be protected thus saving the need for block injections in young subjects and alleviating later orthodontic problems.

Animals↗
PubMed1976

Quantitative aspects of pertechnetate concentration in human parotid and submandibular salivary glands..

Quantitative uptakes of 99Tcm-pertechnetate by the salivary glands have been measured in 36 subjects and normal values established. While uptake over the parotid gland increased with time, parotid uptakes were higher at all time intervals than uptakes over the submandibular glands. The uptake over the submandibulars also increased with time. There was no significant difference between resting uptakes of right and left glands, a significant difference would therefore suggest the presence of pathology. Values over the parotid gland are greater under resting conditions than following stimulation, but no such difference was noted for submandibular glands. However, with stimulated glands it was also shown that there was no significant difference between the right and left parotid, or rignt and left submandibular uptakes. The clinical relevance of these findings is discussed.

Adult↗