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Biomedical subjects

R Coles

Publications and source records attributed to R Coles.

At least 19 recordsLinked to original sources
PubMed1992

Image comparison techniques for use with megavoltage imaging systems.

In this paper we describe software facilities for enabling patient positioning studies using the megavoltage imaging system developed at the Royal Marsden Hospital and Institute of Cancer Research. The study focuses on the use of the system for three purposes: patient position verification (by comparing images taken at treatment simulation with megavoltage images taken at treatment time); reproducibility studies (by analysing a set of megavoltage images); and set-up correction (by adjusting the set-up until the megavoltage image obtained at treatment registers with the simulation image). The need is discussed for suitably presented simulator images, a method of determining field boundaries and the possibility of delineating soft-tissue interfaces. Several algorithms of different types, developed specifically for the purpose of intercomparison of planar projection images, are presented. The techniques employed and their usefulness, in both the qualitative and the quantitative sense, are discussed. The results are presented of a phantom and clinical study, to evaluate the rigour and reproducibility of the algorithms. These results indicate that measurements can be made to an accuracy of about 1-2 mm, with a similar value for interobserver reproducibility for the best image comparison techniques available.

Algorithms↗
PubMed1991

A trial of tinnitus therapy with ear-canal magnets.

A double-blind trial of Takeda's treatment of tinnitus by placing rare-earth magnets close to the tympanic membrane was carried out on 50 patients. The trial failed to show significant benefit from this line of therapy.

Double-Blind Method↗
PubMed1990

A rat granulosa cell plasminogen activator bioassay for FSH in human serum.

A previously described in-vitro rat granulosa cell plasminogen activator bioassay for FSH has been modified and applied in the assay of human serum. This modified method consists of exposing the diethylstilboestrol-stimulated granulosa cells from 25- to 26-day-old rats to FSH or test substance for 3.5 h in wells coated with 125I-labelled fibrinogen and treated with thrombin. Following stimulation with FSH, the dose-related production of plasminogen activator was measured as the degree of 125I-labelled fibrinolysis in the presence of added plasminogen. Using the urinary FSH/LH bioassay reference preparation as the assay standard, the useful range of the assay was 0.3-15 IU/l, with an assay sensitivity of 0.3 IU/l. As determined using purified glycoprotein hormone preparations, the assay was highly specific for FSH. The minor degree of FSH bioactivity measured in some of the hormone preparations was accounted for by the amount of FSH contamination in these preparations. To abolish interference caused by unknown serum factors, we heat-treated the serum samples for 15 min at 56 degrees C before the assay. The results indicated that neither immunoreactivity nor bioactivity was affected by this treatment. Furthermore, heat-treated human sera gave responses parallel to the standard curve at the three dose levels (2, 4 and 8 microliters) studied. We used this bioassay to estimate the FSH-like bioactivity in 15 human serum samples. The estimates of immunoreactive FSH in these samples correlated well with the corresponding FSH bioactivity (r = 0.745, n = 15 and P less than 0.05). The results indicate that with this sensitive and rapid (completed within 24 h) bioassay, it should be possible to measure FSH bioactivity in heat-treated human serum samples.

Animals↗
PubMed1988

Confidants and family structure in old age.

Previous research has shown that confiding has a major influence on well-being in old age, but little is known about the availability and selection of confidants. Drawing from a survey of the social networks of 1,050 persons aged 60 and older in Sydney, Australia, this study explored aspects of the influence of age, gender, and family structure in predicting the choice of confidants among potentially available spouses, children, siblings, and other persons in informal relationships. Logistic regression was used because the response variable was dichotomous and because several explanatory variables, which were both categorical and continuous, were being examined simultaneously. The findings indicated that people tended to confide in more distant family or nonfamily when close family members were not available. The relative importance of variables differed substantially between types of confiding relationships and between gender and age groups of respondents. Our findings suggest the need for longitudinal research and more sensitive methods of analysis in exploring the complexities of maintaining and re-forming primary bonds through the course of old age.

Age Factors↗
PubMed1987

Patterns of exposure of schoolchildren to amplified music.

The amplified-music listening habits and the hearing status of 1443 comprehensive schoolchildren have been surveyed by questionnaire. In a stratified sample of them (n = 25), the levels at which they would listen to a personal cassette player (PCP) in various circumstances were measured. The main conclusion drawn was reassuring: that these children seem to be more conservative in their music-listening habits than young people are commonly given credit for. Nevertheless, music may sometimes make a small contribution to socioacusis and to the total noise dosage of those exposed to noise occupationally. Some recommendations are made for manufacturers of PCPs, and for some restrictions on the use of PCPs in occupational noise.

Adolescent↗
PubMed1986

Correlation between fibre content of the lungs and disease in naval dockyard workers.

In the period 1966-82 lungs from 333 workers who had been employed at a Royal Naval dockyard were referred to the MRC Pneumoconiosis Unit where they were investigated for the severity of asbestosis, the presence of tumours, and an assessment of mineral fibre content and the type and amount of mineral present. The occupational exposure to mineral dust has been coded for 189 of these cases. There is good correlation between the severity of asbestosis and the coded exposures, electron microscopic mineral fibre count, and the fibre count as seen under the light microscope. The information collected showed that mesotheliomas occurred in those who had had minimal or slight asbestosis, by contrast with the pulmonary carcinomas found in those with moderate to severe asbestosis. The amphibole (crocidolite and amosite) lung content correlated with severity of asbestosis.

Aged↗