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Biomedical subjects

M Brewis

Publications and source records attributed to M Brewis.

9 recordsLinked to original sources
PubMed2000

The synthesis and glass-forming properties of phthalocyanine-containing poly(aryl ether) dendrimers.

The synthesis, structural characterisation and properties of a number of phthalocyanine-containing dendrimers are described. Peripheral substitution of phthalocyanine (Pc) with four poly(aryl ether) dendritic wedges (1st, 2nd or 3rd generation) produces materials whose properties are dominated both by the columnar self-association of the Pc core and by the glass-forming character of the dendritic substituents. Asymmetric Pcs containing a single poly(aryl ether) dendron display a columnar mesophase, the structure of which can be frozen into an anisotropic glass at room temperature. Placing the dendritic wedges at the axial sites of silicon phthalocyanine prohibits self-association and gives materials from which can be fabricated robust, isotropic solid solutions of Pc with high glass transition temperatures. A single crystal X-ray diffraction analysis of one of these compounds illustrates the ability of the axial dendrons to prevent cofacial aggregation in the solid state.

Journal Article↗
PubMed1981

Natural history of autoimmune thyroiditis.

One hundred and sixty-three asymptomatic people with thyroid antibodies or raised serum thyrotrophin (TSH) concentrations, or both, and 209 age-matched and sex-matched controls without either marker of thyroid disorder were followed up for four years to determine the natural history of autoimmune thyroiditis. Mildly raised TSH concentrations alone and the presence of thyroid antibodies alone did not significantly increase the risk of developing overt hypothyroidism during the four years compared with the controls. Overt hypothyroidism developed at the rate of 5% a year in women who initially had both raised TSH concentrations and thyroid antibodies. Prophylactic treatment with thyroxine may be justified in women found to have both markers of impending thyroid failure. The cost effectiveness of screening the adult population remains to be evaluated.

Adult↗
PubMed1978

Thyroid hormone concentrations in a large scale community survey. Effect of age, sex, illness and medication.

Total thyroid hormone concentrations have been measured in the course of a large scale community survey to determine the distribution of these variables in the normal population and to assess the effect of age, sex, previously undectected thyroid disease and medication upon these parameters. 2779 subjects were studied. Serum T4 concentrations were normally distributed. A progressive increase in T4 levels with age was noted in the males, and a smaller increase in females which was concealed by the raised T4 values secondary to oral contraceptive therapy in females under the age of 45. Serum T3 levels were also normally distributed. There was a small reduction in T3 with age in the males but this fall was not seen in the females. T3 values were relatively higher in females under the age of 45 but this increase was not noted after exclusion of subjects taking an oral contraceptive. The changes in thyroid hormone concentrations with age are relatively minor (particularly with respect to T3) in a randomly selected sample from an English town. It is suggested that the changes reported by other authors reflect the process of selection used, and the high frequency of undetected thyroid disease, other illness and medication in hospital-based communities.

Adolescent↗
PubMed1976

Electors not liable for jury service as a sampling frame for the elderly.

Data from 449 persons aged over 65 who had been respondents to a population-based survey and 96 non-respondents aged over 65 were studied to compare those who had declared their age at electoral registration with those who had not. It was found that only 75% (79% of respondents and 57% of non-respondents) had declared their age. In an analysis of 16 variables among the respondents, a statistically significant difference for social class among males was found in that relatively fewer from Social Classes IV and V had declared their age. As an administrative instrument for estimating the size of the elderly population, the list of those marked as not liable for Jury Service on the electoral roll is clearly inadequate, giving an underestimate of about 25%. This could possibly be improved upon by better design of the electoral return form.

Age Factors↗
PubMed1968

Recent history of ischaemic heart disease and duodenal ulcer in doctors.

Data are presented on the incidence of ischaemic (coronary) heart disease and duodenal ulcer among the several thousand male medical practitioners aged 35-64 holding immediate sickness benefit policies with the Medical Sickness Annuity and Life Assurance Society Limited. Three periods are considered: 1947-50, 1957-60, and 1961-5.The incidence of first clinical episodes of ischaemic heart disease in the doctors altered little between 1947-50 and 1957-60 but increased in 1961-5. Comparison of the late 1940s with the early 1960s shows a 60% rise of incidence at ages 45-54 but little change at other ages. Cases first presenting as "sudden" death increased between 1947-50 and 1961-5 by 111% at 45-54, and again changed little at 55-64. In two other occupational groups that have been studied-bus conductors and insurance salesmen-the increase of incidence was greater than for the doctors at 45-54 and it occurred also over 55 years of age. The increase from 1947-50 to 1961-5 in mortality during all episodes of ischaemic heart disease was the same in the doctors as in the male population of England and Wales at 45-54, but at 55-64 it was less.The results in the doctors are not due to alterations over the period in length of sickness absence, or underwriting policy, or of the nomenclature used on the certificates.Well-documented changes in the smoking habits of doctors may be partly responsible for what appears to have been a relatively favourable experience of ischaemic heart disease from 1947-50 to 1961-5, especially at ages 55-64.Incidence of duodenal ulcer at ages 35-64 declined steadily in this population of doctors from 1947-50 to 1961-5. The decline is very likely to be real.

Adult↗