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Biomedical subjects

T W Meade

Publications and source records attributed to T W Meade.

At least 217 records · Page 12Linked to original sources

Haemostatic, lipid, and blood-pressure profiles of women on oral contraceptives containing 50 microgram or 30 microgram oestrogen.

In 15 women on oral contraceptives containing 30 microgram oestrogen, mean values for factors II, VII, and X, fibrinogen, fibrinolytic activity, antithrombin III, cholesterol, and fasting triglycerides were intermediate between values for 63 women on preparations containing 50 microgram oestrogen and those for 243 premenopausal women not on oral contraceptives. Mean blood-pressure levels, however, were higher in women on 30 microgram than in those on 50 microgram preparations. In 28 women on 50 microgram preparations containing 3 mg or 4 mg norethisterone, mean values of factor VII, fibrinogen, fibrinolytic activity, cholesterol, fasting triglycerides, and systolic blood-pressure were higher than in 15 women whose preparations contained only 1 mg of norethisterone. A less consistent picture was found in women on 30 microgram oestrogen preparations containing either 250 microgram (10 women) or 150 microgram (5 women) d-norgestrel. It is concluded that 30 microgram oestrogen preparations probably result in smaller hemostatic and lipid changes than 50 microgram preparations but that they may have a blood-pressure-raising effect attributable to the particular progestagen, d-norgestrel, used in 30 microgram preparations. The safety of these 30 microgram oestrogen preparations may thus depend partly on the balance between these two sets of effects. It is also concluded that norethisterone may have effects similar to those attributed to oestrogens.

Adult↗

Lipid and lipoprotein concentrations in 1604 men and women in working populations in north-west London.

Serum lipid and lipoprotein concentrations in men and women vary with age, and so-called "normal" limits should take account of this. Serum cholesterol, triglyceride, and phospholipid concentrations were measured in 1027 men and 577 women in five working populations in north-west London, and lipoprotein electrophoresis and quantitative analyses of lipoprotein concentrations were also performed. In men the best fit between serum cholesterol, triglycerides, and phospholipids, on the one hand, and age, on the other, was given by a curvilinear relationship expressed as a quadratic regression. In women the best fit was given by a linear regression. White men had higher serum cholesterol and triglyceride concentrations than Black men, and these differences were reflected in the distributions of the lipoproteins. There were no differences between values in White and Black women. Young women on oral contraceptives had lipid concentrations similar to those of older women not on these preparations. These data suggest that the adoption of concentrations of serum cholesterol (275-300 mg/100 ml (7-1-7-8 mmol/l) and triglycerides (175-200 mg/100 ml (2-0--2-3 mmol/l) recommended by a recent report on the prevention of coronary disease as limits above which special attention should be given to the management of hyperlipidaemia could result in as few as 2% of younger men or as many as 31% of older men being selected for treatment.

Adolescent↗

"Right" stay in hospital after sugery: randomised controlled trial.

A randomised controlled trial was carried out on 100 patients to compare the effects of discharge after certain pre-specified clinical criteria had been fulfilled--"right" stay--with those of discharge at an arbitrary 10 days after surgery--"fixed" stay. The operations concerned (cholecystectomy and vagotomy) were more hazardous than those previously included in studies of early discharge. Patients in the right-stay group were discharged, on average, 7-6 days after operation--that is, two days earlier than those in the fixed-stay group. In terms of clinical progress, social factors such as return to work, and the acceptability to patients and relatives of the implications of right stay, patients in this group fared as well as those in the fixed-stay group, and in some respects slightly better. Right stay entailed the transfer of some work from hospital to community medical and nursing staff, but this also was acceptable. The concept and use of the right-stay principle is of value in planning the postoperative discharge of suitable patients.

Adult↗

Cigarette smoking patterns during the working day.

The rates at which people smoke cigarettes during different periods of the day were obtained from three occupational groups. Group 1 consisted of those working at the main London production site of a food processing factory, Group 2 consisted of those in the administrative offices of the same company; there are smoking restrictions at both. Group 3 consisted of workers in the offices of a London borough where there are no smoking restrictions. Replies were received from 3174 people, or 88% of those approached. There was a higher proportion on non-smokers (over 70%) among the two groups of office workers than among the food processing workers (about 55%). Smokers in Group 3 recorded somewhat higher average cigarette consumption than those in Groups 1 and 2. During different periods of the day, the maximum hourly rate of cigarette smoking was about three times the minimum rate. For Groups 1 and 2 the maximum rate was consistently during the interval between leaving work and going to bed. In contrast, the maximum rate for Group 3 was consistently during the afternoon, while at work, and the rate between leaving work and going to bed was similar to the rate for the day as a whole. Results will help in deciding the time of day at which blood for carboxyhaemoglobin estimations should be taken.

Circadian Rhythm↗

Factor V in an industrial population.

Factor-V levels have been measured in a random sample of 626 men and 307 women working in a variety of occupations in North West London. The method is an automated one-stage assay using the same batch of freeze-dried thromboplastin, all results being expressed in terms of the same freeze-dried standard plasma; it has been shown that only one dilution of test plasma is necessary. Factor-V levels are significantly higher when venepuncture is difficult than when it is satisfactory, the mean levels being about 130% and 117% respectively. Factor-V levels are approximately normally distributed; they are similar in men and women and in blacks and whites, and increase significantly with age at the rate of about 0.6% per annum. Factor-V levels are not affected by oral contraceptives or the menopause, and there are no differences according to blood group or secretor status.

Adult↗

An epidemiological study of the haemostatic and other effects of oral contraceptives.

Factors V, VII and VIII (each determined by biological assay), fibrinogen, platelet count and adhesiveness, and fibrinolytic activity were measured in 234 white pre-menopausal women, of whom 57 (24%) were on oral contraceptives and 177 (76%) were not. Cholesterol, triglyceride and blood pressure levels were also recorded. In 20 of the women on oral contraceptives, and in an age-matched group of 20 who were not, prothrombin, factor X, antithrombin III and alpha 2-macroglobulin levels were determined, and factors VII and VIII were also measured immunologically. For the majority of the variables studied, the differences between those using and not using oral contraceptives were greater in younger than older women; in the case of factor VII (biological assay) and fibrinogen, the differences between the regression slopes on age were statistically significant, and mean values were substantially higher in those on oral contraceptives. There was also a significant difference between regression slopes on age for cholesterol. Mean levels of prothrombin, factors VII (immunological assay) and X, triglycerides and blood pressure were significantly higher, and mean levels of antithrombin III significantly lower, in those on oral contraceptives compared with those not. Overall, fibrinolytic activity was significantly higher in the women on oral contraceptives; this difference was, however, almost entirely due to the greatly increased fibrinolytic activity of the non-smokers on oral contraceptives, activity in the smokers on oral contraceptives being similar to that of the women not on these preparations. There were no significant differences in mean platelet count or adhesiveness, or in haemoglobin, packed cell volume, uric acid and blood sugar levels. Among the women on oral contraceptives, there was a significant negative correlation between factor VIII and fibrinolytic activity; this was largely due to five women all of blood groups A and B, in whom, besides high factor-VIII levels and poor fibrinolytic activity, other variables (e.g. fibrinogen) were raised in a direction that might be expected to favour thrombogenesis. It is possible that it is those women whose fibrinolytic activity does not increase in order to compensate for the effects of oral contraceptives on clotting factors, lipids and blood pressure, who are at special risk of thromboembolic episodes. The differential effects of oral contraceptives by age must be borne in mind in evaluating the effects of these preparations on the haemostatic and lipid systems.

Age Factors↗