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Biomedical subjects

C C Macintyre

Publications and source records attributed to C C Macintyre.

At least 19 recordsLinked to original sources

Smoking, lipids, glucose intolerance, and blood pressure as risk factors for peripheral atherosclerosis compared with ischemic heart disease in the Edinburgh Artery Study.

The aim was to determine if certain risk factors in the general population are more strongly related to peripheral arterial disease than to ischemic heart disease. Arterial disease in the lower limbs was measured by means of the World Health Organization questionnaire on intermittent claudication, the ankle brachial pressure index, and a reactive hyperemia test in 1,592 men and women aged 55-74 years selected randomly in 1988 from the age-sex registers of 10 general practices in Edinburgh, Scotland. Peripheral arterial disease was strongly related to lifetime cigarette smoking, with additional risks in current and exsmokers of less than 5 years. Multiple regression of risk factors on measures of peripheral arterial disease showed associations with diabetes mellitus (but not impaired glucose tolerance), systolic blood pressure, and serum cholesterol; inverse association with high-density lipoprotein cholesterol; and only univariate association with triglycerides. In multiple logistic regressions of risk factors on six separate indicators of cardiovascular disease, the only consistent difference was that smoking increased the risk of peripheral arterial disease (range of odds ratios, 1.8-5.6) more than heart disease (range of odds ratios, 1.1-1.6). Diabetes mellitus was not a stronger risk factor for peripheral arterial disease.

Aged

The effect of weaning diet on the subsequent colonic metabolism of dietary fibre in the adult rat.

The effect of the weaning diet on the subsequent colonic metabolism of bran and pectin in the adult rat has been investigated. Feeding a fibre-reduced diet on its own or supplemented with bran (WB) and pectin (P) from weaning (fibre-reduced (weaning)) was compared with introducing the same diet to age-matched rats reared on a standard laboratory diet from weaning (fibre-reduced (6 weeks)). The effects of the diets on colonic metabolism were measured by wet and dry caecal contents and stool weights, caecal sac weight, and caecal and faecal short-chain fatty acids (SCFA). Final body-weights were greater for fibre-reduced (6 weeks) and fibre-reduced (6 weeks) + P groups, but not fibre-reduced (6 weeks) + WB, than those of the fibre-reduced (weaning) rats. Rats fed on fibre-reduced (6 weeks) diet had a higher total caecal SCFA content than fibre-reduced (weaning) control rats. Fibre-reduced (weaning) + P-fed rats had a threefold higher caecal concentration of both propionate and butyrate than the matched fibre-reduced (6 weeks) + P group. Fibre-reduced (weaning) + WB animals had a significantly higher butyrate caecal concentration compared with their matched fibre-reduced (6 weeks) + WB group. Fibre-reduced (weaning) + P-fed rats had a lower faecal output than the fibre-reduced (6 weeks) + P rats. There was no difference in faecal output in rats fed on either fibre-reduced (6 weeks) + WB or fibre-reduced (weaning) + WB. The faecal concentration of SCFA was in general higher in the rats fed on fibre-reduced (weaning) alone, + P, or + WB than in those fed on fibre-reduced (6 weeks) alone, + P or + WB. Faecal output of total and individual SCFA was increased on the fibre-reduced (weaned) + WB diet compared with fibre-reduced (6 weeks) + WB-fed animals. The diet at weaning may be important in determining the pathways of caecal bacterial metabolism in the adult rat. In studying the effect of a dietary fibre on caecal metabolism and faecal output, when the diet is changed appears to be important.

Animals

Relationships of plasma viscosity, coagulation and fibrinolysis to coronary risk factors and angina.

Plasma viscosity, molecular markers of activated coagulation and fibrinolysis (fibrinopeptides A and B beta 15-42), coagulation factors (fibrinogen and factor VII) and antiplasmins were measured in 529 men aged 35-54 years and related to new angina pectoris (n = 117) and to coronary risk factors in controls without angina (n = 412). Five major risk factors (cigarette-smoking, blood pressure, cholesterol, triglyceride and body mass index) were each associated with increases in plasma viscosity, coagulation factors, and imbalance of coagulation over fibrinolysis (increased ratio of fibrinopeptide A/fibrinopeptide B beta 15-42). Increased viscosity and fibrinogen in smokers were partly reversed in ex-smokers, but the imbalance of coagulation and fibrinolysis persisted. Cholesterol and triglyceride were also associated with increased antiplasmin activity. In men with angina, only fibrinogen was elevated compared to controls. We suggest that increased plasma viscosity and an imbalance of coagulation over fibrinolysis may be mechanisms by which known risk factors promote arterial thrombosis, but are not present in stable angina.

Adult

Risk of angina pectoris and plasma concentrations of vitamins A, C, and E and carotene.

The relation between risk of angina pectoris and plasma concentrations of vitamins A, C, and E and carotene was examined in a population case-control study of 110 cases of angina, identified by the Chest Pain Questionnaire, and 394 controls selected from a sample of 6000 men aged 35-54. Plasma concentrations of vitamins C and E and carotene were significantly inversely related to the risk of angina. There was no significant relation with vitamin A. Smoking was a confounding factor. The inverse relation between angina and low plasma carotene disappeared and that with plasma vitamin C was substantially reduced after adjustment for smoking. Vitamin E remained independently and inversely related to the risk of angina after adjustment for age, smoking habit, blood pressure, lipids, and relative weight. The adjusted odds ratio for angina between the lowest and highest quintiles of vitamin E concentrations was 2.68 (95% confidence interval 1.07-6.70; p = 0.02). These findings suggest that some populations with a high incidence of coronary heart disease may benefit from eating diets rich in natural antioxidants, particularly vitamin E.

Adult

Edinburgh Artery Study: prevalence of asymptomatic and symptomatic peripheral arterial disease in the general population.

Intermittent claudication has been studied in cardiovascular surveys but limited information is available on asymptomatic peripheral arterial disease. The purpose of this paper is to describe the prevalence of both asymptomatic and symptomatic disease and relation to ischaemic heart disease in the Edinburgh Artery Study. A cross-sectional survey was conducted on an age-stratified sample of men and women aged 55 to 74 years selected from age-sex registers in ten general practices in the city. Arterial disease was assessed in 1592 participants by means of the WHO questionnaire on intermittent claudication and measurement of the ankle brachial systolic pressure index (ABPI) and change in ankle systolic pressure during reactive hyperaemia. The prevalence of intermittent claudication was 4.5% (95% confidence interval (CI): 3.5%-5.5%). Major asymptomatic disease causing a significant impairment of blood flow occurred in 8.0% (95% CI: 6.6%-9.4%). A further 16.6% (95% CI: 14.6%-18.5%) had criteria considered abnormal in clinical practice: 9.0% had ABPI less than 0.9 and 7.6% had reactive hyperaemia pressure reduction greater than 20%. Intermittent claudication was equally common in both sexes. The ABPI and reactive hyperaemia results suggested a slight preponderance of asymptomatic disease in males and were consistent with an increasing prevalence with age and lower social class. Mean ABPI was higher in normal men than women, and was lower in the left leg than the right suggesting a unilateral predisposition to disease. Subjects with major asymptomatic disease had more evidence of ischaemic heart disease than in the normal population (relative risk (RR) 1.6; 95% CI: 1.3-1.9).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors

The effects of age, sex, and smoking on normal pharyngoesophageal motility.

Previous reports of normal pharyngoesophageal motility have described normal ranges in small numbers of young adults. In this study, the results of upper esophageal sphincter (UES) manometry with a microtransducer assembly in 67 healthy volunteers aged 17-77 yr have been analyzed for possible effects of age, sex, and cigarette smoking. Older subjects were found to have only marginally lower UES tonic pressures, but markedly elevated pharyngeal contraction pressures. Increasing age was associated with a reduction in duration of upper esophageal contractions and, for bread swallows, an increase in pharyngoesophageal wave velocity which may represent compensatory mechanisms for airway protection. Male subjects showed greater UES axial asymmetry than females, perhaps due to sex differences in laryngeal anatomy, whereas females had greater UES wet swallow after-contraction pressures which may be relevant to the generation of globus sensation. All results were independent of cigarette smoking. We conclude that normal values obtained in small numbers of young adults form an inadequate basis for the interpretation of UES tonic and pharyngeal contraction pressures, which are reported to be abnormal in older patients with dysphagia, and that manometric investigation of dysphagic patients requires the analysis of multiple parameters of dynamic pharyngoesophageal function.

Adult

Increasing incidence of aortic aneurysms in England and Wales.

The numbers of patients being admitted to hospital with aortic aneurysms have increased recently. A study was carried out to try to find out whether this was a true increase in incidence or whether it could be attributable to more accurate diagnosis and better surgical techniques. From analyses of routine statistics it was found that from 1950 to 1984 age standardised mortality rose 20-fold in men to 47.1 per 100,000 population and 11-fold in women to 22.2 per 100,000 and that this was mainly due to more deaths from abdominal aneurysms. Hospital admissions of men with abdominal aneurysms were found to have increased steadily from 1968 to 1983, but the increase for women admitted did not begin until 1978. An increase in both emergency and elective admissions and only a marginal fall in deaths in hospital (from 45% to 39%) suggest that admissions for abdominal aneurysms increased across a wide range of severity of disease. It is concluded for the following reasons that the true incidence of aortic aneurysms, particularly abdominal aneurysms, has been increasing in England and Wales: the trends are not wholly compatible with advances in diagnosis and surgery, there are inconsistencies by age and sex, and increases have occurred in the number of complicated as well as uncomplicated cases.

Adult

Pharyngoesophageal dysmotility in globus sensation.

Ambulatory esophageal pH monitoring, radiologic examination, endoscopy, and manometry were undertaken in 142 patients with globus. The results demonstrate that abnormal gastroesophageal reflux occurred in 23% of patients, implying that, while reflux may be responsible for globus in some patients, it is not the cause of globus sensation in the majority of individuals with this symptom. Comparing patients with globus and control subjects, there were no differences in lower esophageal sphincter pressures, esophageal body motility, or tonic upper esophageal sphincter pressures, but patients with globus exhibited higher pharyngeal and upper esophageal sphincter after-contraction pressures during deglutition. The physiological significance of this pharyngeal and upper esophageal dysmotility is not clear and it may be no more than a secondary phenomenon. Alternatively, it may contribute to the generation of globus, perhaps in combination with other physical and psychological triggers.

Diagnosis, Differential

Normal pharyngoesophageal motility. A study of 50 healthy subjects.

Upper esophageal manometry is technically problematic. Published normal values are, therefore, few and wide ranging, reflecting catheter and recording-system variables, while the reproducibility of measurements and the influence of food consistency have been little studied. In this investigation, 50 healthy volunteers were studied with (1) a 2.8-mm-diameter six-sensor catheter-mounted transducer assembly and (2) a 3.2 X 7.2-mm sleeve device linked to a computerized recorder with a pressure-sample rate of 32/sec. The study protocol included water, bread, and semisolid swallows. Upper esophageal sphincter (UES) tonic pressures measured with the catheter-mounted assembly were lower and more reproducible than pressures measured with the sleeve system. Compared with water, bread swallows showed greater pharyngeal and sphincter after-contraction pressures, while semisolid swallows had less complete sphincter relaxation. Duration of pharyngoesophageal contractions was greater with bread or semisolid than water. The observations have established normal values for measurements of UES function and, in addition, have shown that (1) catheter variables significantly influence the measurement of upper sphincter tonic pressure, (2) pressures recorded with the catheter-mounted transducer are most reproducible, and (3) pharyngoesophageal motility patterns vary significantly according to the substance swallowed.

Adult

Surveillance of an at risk population: assessment of postal urine cytology.

The urine postal cytology kit Urotel was assessed against our standard cytological method; 184 patients attending for routine surveillance cystourethroscopy provided free flow urine specimens. The urine cytology was reported blind. Comparison of the 2 tests showed similar specificity but significantly higher sensitivity with the Urotel kit. These kits may have a place in the surveillance of patients at high risk of recurrent tumour or those with carcinoma in situ, reducing the frequency of hospital attendance.

Humans

Low plasma vitamins E and C. Increased risk of angina in Scottish men.

Cross-cultural studies suggest that low plasma antioxidant levels contribute to the high incidence of coronary heart disease (CHD) in Scotland. One hundred twenty-five cases of angina without reported history were identified by a postal WHO chest pain questionnaire from a systemic population sample of 6000 Edinburgh men (35-54 years). Classical CHD risk factors (lipids, blood pressure, smoking, and relative weight), plasma vitamins, and a new independent CHD risk factor, adipose tissue linoleate, were measured in angina (n = 125) and healthy controls (n = 430). Cigarette smoking was common in angina (46% vs. 29%, p less than 0.01), and adipose tissue linoleate was lower (8.77 +/- 0.18% vs. 9.81 +/- 0.14% (p less than 0.01). Classical CHD risk factors were not different. Vitamin E/cholesterol molar ratio (micron/mM) was lower in angina than in controls: 1.58 +/- 0.03 vs. 1.66 +/- 0.02 (p less than 0.01). Plasma vitamin C was also lower in angina than in controls: 23.6 +/- 1.7 vs. 30.5 +/- 1.1 microM (p less than 0.001). The relative risk of angina for those in the lowest versus those in the highest quintile of the vitamin E/cholesterol ratio distribution was 2.2:1, irrespective of other risk factors (p less than 0.009). Adipose tissue linoleate removed the association between vitamin E and angina. The relative risk of angina for those in the lowest versus those in the highest quintile of plasma vitamin C was 2.6:1 (p less than 0.01), and the increased risk was also independent of classical risk factors, but closely related to a smoking habit. Low plasma vitamin E or adipose linoleate predisposes to angina, and smoking may increase the risk of angina by lowering plasma vitamin C levels in Scottish men.

Adult

Abnormal eating attitudes in young insulin-dependent diabetics.

All insulin-dependent diabetics between the ages of 16 and 25 years attending the diabetic clinic at the Royal Infirmary, Edinburgh, (152 women and 139 men) were asked to complete the EAT, the EDI, and the GHQ, and to provide a control subject (sibling or close friend) of similar age who would do likewise. Marked differences were found between diabetic women (but not men) and their controls in eating attitudes, in many of the psychological characteristics associated with eating disorders, and in GHQ scores. Although some of the women had classic anorexia nervosa or bulimia, others with abnormal eating attitudes did not fulfil the formal criteria. Overall, diabetics were significantly heavier than controls but the differences in eating attitudes were not eliminated by correcting for overweight. Abnormal scores were associated with high HbA1 levels and independently with retinopathy. The weight gain and psychological effects of diabetes are identified as probably of aetiological importance in the abnormal eating attitudes of young diabetic women.

Adolescent

Reproducibility of reactive hyperaemia test in the measurement of peripheral arterial disease.

The reproducibility and sources of variation in ankle and brachial systolic pressures were determined for a reactive hyperaemia test used to assess peripheral arterial disease in the lower limbs. Thirty-six subjects had repeat measurements taken by four observers on two separate days using a Doppler probe and random zero sphygmomanometer. Ankle pressures were measured before and after 4 min of arterial occlusion above the knee. The 95 per cent confidence limits for a postocclusion reduction in pressure was approximately +/- 25 mmHg and for the postocclusion ankle-brachial ratio was +/- 20 per cent. The corresponding figures for the mean of four measurements taken by two observers on 2 days was approximately +/- 17 mmHg and +/- 13 per cent. In patients with vascular disease analysis of variance showed that the greatest sources of variation in the postocclusion ankle-brachial ratio were the 'biological' variations between subjects and between legs. But for postocclusion reductions in pressure, variability due to observers and repeat readings was as important as the 'biological' differences between subjects and legs. Thus, in respect of variability, the ratio may be a better parameter to detect differences between subjects.

Adult

The importance of the time interval between insulin injection and breakfast in determining postprandial glycaemic control--a comparison between human and porcine insulin.

This study assessed the effect of the time interval between insulin injection and breakfast in determining subsequent postprandial glycaemic control and also whether this differed between highly purified porcine insulin and human insulin (crb) in six diabetic patients (age range 24-36 years, duration of diabetes greater than 10 years) usually treated with twice daily Actrapid MC and Monotard MC and with stable insulin requirements and diabetic control. On separate mornings each patient was given, after an overnight fast, their usual dose of either Actrapid MC and Monotard MC or Humulin S and Humulin Zn injected 5, 20, or 40 min before a standard breakfast. The postprandial glycaemic profile was not significantly different at any of the three time intervals with Actrapid MC and Monotard MC. However, with the human insulin the profile was significantly better at the 40 min interval than at the 5 min interval (p less than 0.05) and this was also better than any of the profiles with the porcine insulin, there being a significant difference between the two types of insulin (p less than 0.05). These findings suggest that the time interval between insulin injection and breakfast may be more important with human insulin than with porcine insulin.

Adult

Variability of ankle and brachial systolic pressures in the measurement of atherosclerotic peripheral arterial disease.

The aim of this study was to determine the variability of measurements of ankle and brachial systolic pressures and ankle brachial ratios in order to assess their suitability for use in epidemiological studies of arterial disease in the lower limbs. Thirty-six subjects had repeat measurements taken by four observers on two separate days using a Doppler probe and random zero sphygmomanometer. The variability in the measurement of ankle systolic pressure was comparable to that for brachial systolic pressure. The 95% confidence limits of one measurement of the ankle brachial ratio was estimated to be +/- 16%, reducing to +/- 10% for the mean of four measurements taken by two observers on two days. Analysis of variance indicated that the variability in the measurement of ankle brachial ratios attributable to observers, days, timing of measurements on the same day, and repeat measurements was considerably less than the "biological" variability between subjects and between legs. These results suggest that repeatability of the ankle brachial ratio is such that a single measurement is suitable for most epidemiological studies of atherosclerotic peripheral arterial disease.

Adult