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Biomedical subjects

D G Cook

Publications and source records attributed to D G Cook.

At least 145 records · Page 8Linked to original sources
PubMed1988

Breathlessness, lung function and the risk of heart attack.

Men with moderate or severe breathlessness had a greater than two-fold risk of suffering a major ischaemic heart disease (IHD) event compared to men with no evidence of breathlessness, based on 7.5-year follow-up in a prospective study of 7735 British men aged 40-59 years. Even after adjustment for other risk factors, including cigarette smoking, the relative risk remained two-fold. Men in the lowest fifth of the forced expiratory volume is 1 s (FEV1) distribution also had a two-fold risk of IHD compared to men in the highest fifth after similar adjustment. In part, the role of breathlessness as a risk factor for major IHD events was explained by its strong association with pre-existing, but usually undiagnosed, IHD. However, breathlessness was associated with an increased risk of heart attack even in men without any evidence of pre-existing IHD at screening. FEV1 was related to risk of a major IHD event in men without evidence of pre-existing IHD at screening and in men with previously undiagnosed IHD detected at screening. Measures of breathlessness and lung function could be more widely used in clinical situations and in screening as additional independent indicators of both unrecognized IHD and of risk for major IHD events.

Adult↗
PubMed1987

Social class differences in ischaemic heart disease in British men.

To examine why ischaemic heart disease (IHD) mortality rates in Britain are higher in manual than in non-manual workers 7735 middle-aged men in the British Regional Heart Study were followed up for 6 years, during which time 336 men experienced a major IHD event (fatal or non-fatal myocardial infarction or sudden cardiac death). The prevalence rates of IHD at screening, were higher in manual workers. Also, the attack rate of major IHD events during follow-up was 44% higher in manual workers. Marked differences in cigarette smoking contributed substantially to the increased risk of IHD in manual workers, who also had higher levels of blood pressure, were more obese, and took much less physical activity in leisure time. Adjustment for differences in these risk factors narrowed the gap between manual and non-manual workers in attack rates of IHD. Since the risk of IHD in Great Britain is high in all social classes, there would seem to be little justification for any overall policy for prevention of IHD to focus on social class. However, anti-smoking strategies might well take into account the social class differences described.

Adult↗
PubMed1987

Type A behaviour and ischaemic heart disease in middle aged British men.

The Bortner questionnaire, which measures aspects of type A (coronary prone) behaviour was completed by 5936 men aged 40-59 selected at random from one general practice in each of 19 British towns. The presence of ischaemic heart disease was determined at initial examination and the men were followed up for an average of 6.2 years for morbidity and mortality from myocardial infarction and for sudden cardiac death. Non-manual workers had significantly higher scores (more type A) than manual workers and the score decreased (less type A) with increasing age. After adjustment for social class and age men with higher scores had higher prevalences of ischaemic heart disease less marked for electrocardiographic evidence and more marked for response to a chest pain questionnaire (angina or possible myocardial infarction). A man's recall of a doctor's diagnosis of ischaemic heart disease, however, did not relate to his Bortner score. There was no significant relation between the Bortner score and the attack rate or incidence of major ischaemic heart disease events. In this study type A behaviour, as measured by the Bortner questionnaire, did not predict major ischaemic heart disease events in British middle aged men.

Adult↗
PubMed1987

Non-participation and mortality in a prospective study of cardiovascular disease.

Men who did not participate in a prospective study of cardiovascular disease (The British Regional Heart Study) were younger than the participants, more likely to be unmarried, and more likely to be less skilled workers. In the first three years of follow-up, their total mortality rate was significantly higher than that of the participants; thereafter it declined to levels not significantly different from those of the participants. This excess of early deaths could not be attributed to age. There was a small but non significant excess mortality in non-participants due to neoplasms and cardiovascular disease and a somewhat greater excess from all other causes combined. The social characteristics of the non-participant population appear to contribute to their significantly higher total mortality rate, and allowance needs to be made for this in interpreting the study findings. However the death rate from cardiovascular disease was similar in participants and non-participants, suggesting that any analysis related to this particular cause of death should not be biased by non-participation.

Adult↗
PubMed1986

Giving up smoking and the risk of heart attacks. A report from The British Regional Heart Study.

In a prospective study of 7735 middle-aged men, both current and ex-cigarette-smokers had a risk of a major IHD event, within an average 6.2 years of screening, more than twice that in men who had never smoked cigarettes; men who had given up smoking more than 20 years ago still had an increased risk. This excess risk among ex-smokers is only to a small extent explained by their higher blood pressure, serum total cholesterol, and body-mass index. An increased prevalence of IHD in men who had recently given up smoking also made a small contribution to excess risk. In both current and former cigarette smokers, the number of years a man had smoked cigarettes ("smoking-years") was the clearest indicator of IHD risk due to cigarettes. The major benefit of giving up smoking may lie in halting the accumulation of smoking years.

Adult↗
PubMed1986

Operant conditioning of head waving in Aplysia.

Head waving is a naturally occurring behavior that Aplysia use to explore their environment. Aplysia can be operantly trained to modify their head-waving response, increasing the amount of head waving on one side of their body in order to terminate the presentation of an aversive strong light. Acquisition of the operant response is rapid, within 10 min. Two observations indicate that the operant conditioning is under the control of the contingencies of reinforcement: (i) contingent reinforcement significantly elevates operant responding, reversing the contingencies significantly reduces operant performance, and reinstating the contingencies significantly reinstates operant responding; and (ii) yoked controls do not acquire the operant response, yet these same animals readily learn when reinforcement is made contingent upon their responses. Finally, internally derived cues (e.g., proprioceptive or reafferent) appear to play a predominant role in acquiring the operant response. Since progress has been made in understanding the cellular basis of classical conditioning in Aplysia, this demonstration of operant conditioning in a response system that is well-suited for a cellular analysis provides a preparation in which it is possible both to analyze the cellular mechanisms of operant conditioning and to address the theoretical question of the relationship between classical and operant conditioning on a mechanistic level.

Animals↗
PubMed1986

Serum uric acid, serum glucose and diabetes: relationships in a population study.

The relationships between serum uric acid, serum glucose and diabetes have been examined in a survey of 7735 middle-aged men drawn at random from general practices in 24 British towns. There was a positive relationship between serum glucose and serum uric acid concentrations up to about 8.0 mmol/l; at higher levels of glucose, serum uric acid decreased. Uric acid levels were significantly reduced in insulin-dependent diabetics and in those on oral hypoglycaemics and also in 'non-diabetics' with casual glucose levels greater than 10 mmol/l. Both uric acid and glucose concentrations were positively related to body mass index; only uric acid was positively related to alcohol intake. Men on antihypertensive treatment had raised levels of uric acid (significant) and glucose (non-significant). The positive relationship between serum uric acid and serum glucose could not be explained by associations with body mass index, alcohol intake, age, social class, gout or treatment for hypertension. It probably reflects the biochemical interaction between serum glucose and purine metabolism, with increased excretion of uric acid during hyperglycaemia and glycosuria.

Adult↗
PubMed1985

Is the clinical trial evidence about new drugs statistically adequate?

The statistical adequacy of all papers published in the period 1976-80 describing clinical trials of five non-steroidal anti-inflammatory and two analgesic drugs introduced into the UK market in 1978 and 1979 has been assessed using a checklist of simple criteria. Most trials were reported to be randomised and double-blind. Trial designs were less satisfactory in other important respects; the sample size of most trials was inadequate to demonstrate superiority of the new drug compared with an active control therapy. The period of treatment assessment was short in view of the likelihood of prolonged prescription of drugs in these classes. It is suggested that licensing authorities should demand higher standards of clinical trial evidence offered in support of new drugs.

Anti-Inflammatory Agents↗
PubMed1984

A case of envenomation by the neotropical colubrid snake, Stenorrhina freminvillei.

The case history of a bite by the neotropical opisthoglyph, Stenorrhina freminvillei, is presented. This is apparently the first documentation of human envenomation by this genus. Localized pain and swelling were the predominant symptoms; no systemic reaction was noted. Such mild effects are consistent with the bites reported for other New World colubrids, in contrast to the potentially lethal effects produced by Old World colubrid genera Dispholidus, Thelotornis, Rhabdophis and Atractaspis.

Animals↗
PubMed1984

Prevalence of ischaemic heart disease in middle aged British men.

The prevalence of ischaemic heart disease was determined by an administered questionnaire and electrocardiography in 7735 men aged 40-59 years drawn at random from general practices in 24 British towns. Overall, one quarter of these men had some evidence of ischaemic heart disease on questionnaire or electrocardiogram or both. On questionnaire, 14% of men had possible myocardial infarction or angina, with considerable overlap of the two syndromes. The prevalence of possible myocardial infarction combined with angina and of definite angina only showed a fourfold increase over the age range studied. Electrocardiographic evidence of ischaemic heart disease (definite or possible) was present in 15% of men, there being myocardial infarction in 4.2% and myocardial ischaemia in 10.3%. Electrocardiographic evidence of myocardial infarction increased fourfold over the age range studied. There was considerable overlap of questionnaire and electrocardiographic evidence of ischaemic heart disease. Nevertheless, more than half of those with possible myocardial infarction combined with angina had no resting electrocardiographic evidence of ischaemic heart disease, and half of those with definite myocardial infarction on electrocardiogram had no history of chest pain at any time. This national population based study strongly suggests that the prevalence of ischaemic heart disease in middle aged British men is greater than has been indicated by previous studies based on occupational groups.

Adult↗
PubMed1984

Recall of diagnosis by men with ischaemic heart disease.

In a study of the prevalence of ischaemic heart disease in middle aged men in 24 British towns, the subjects were asked whether a doctor had ever told them that they had any form of cardiovascular disease. Their recall of various diagnoses was related to evidence of ischaemic heart disease obtained by an administered questionnaire on chest pain and electrocardiography. Twenty one per cent of men recalled a diagnosis of cardiovascular disease, in one quarter of whom it was ischaemic heart disease. There was a sixfold increase in the prevalence of recall of a diagnosis of ischaemic heart disease over the age range studied. Only one third of the men with possible myocardial infarction on questionnaire recalled such a diagnosis having been made by a doctor. Only half of those with a definite myocardial infarction on an electrocardiogram could recall a diagnosis of ischaemic heart disease. Even in severe (grade 2) angina 40% could not recall being told that they had heart disease. Overall, only one in five of those regarded as having ischaemic heart disease was able to recall such a diagnosis having been made by a doctor, and these were likely to be those most severely affected. Ischaemic heart disease is common in middle aged British men, but most of those affected are apparently not aware of their condition. This low level of awareness among patients and doctors may contribute to a lack of public concern regarding the need for action to reduce the incidence of ischaemic heart disease in Great Britain.

Adult↗
PubMed1983

Multiple regression in geographical mortality studies, with allowance for spatially correlated errors.

In order to provide clues to the aetiology of a disease, mortality indices for different areas are often related to explanatory variables by using multiple regression. However, mortality in nearby areas may be similar for reasons not attributable to the covariates, so the errors will not be independent. This paper suggests a way of finding a parameterized form for the correlated error structure by examining the residuals from an ordinary least squares regression. Such a model is then fitted by using maximum likelihood. An example based on cardiovascular mortality in British towns is used to illustrate the problem and our solution.

Cardiovascular Diseases↗
PubMed1983

Role of habituation and classical conditioning in the development of morphine tolerance.

Rats were tested for the development of analgesic tolerance to low (5 mg/kg) and high (15 mg/kg) doses of morphine once every 12 or 48 hr in distinctive or nondistinctive environments. Results indicated that in a nondistinctive environment, development of analgesic tolerance to morphine (a) is a function of repeated presentation of morphine, (b) is more rapid with massed than with spaced presentations of morphine, (c) is not dependent on variation in drug levels, (d) shows spontaneous recovery across time, and (e) is not sensitive to marked alteration in the environment. It is suggested that in nondistinctive environments the development of tolerance to morphine is mediated by a habituation process. Results show that in a distinctive environment development of analgesic tolerance to morphine (a) is a function of repeated presentation of morphine, (b) is slightly more rapid with spaced than with massed presentations of morphine, (c) is not dependent on variation in drug levels, (d) shows persistence across time, and (e) is sensitive to alteration in the environment. It is suggested that in a distinctive environment the development of tolerance to morphine is mediated by a classical conditioning process that is superimposed on the habituation process.

Animals↗