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Biomedical subjects

C Dollery

Publications and source records attributed to C Dollery.

At least 19 recordsLinked to original sources
PubMed1996

The acute rise in plasma fibrinogen concentration with exercise is influenced by the G-453-A polymorphism of the beta-fibrinogen gene.

We have investigated the effects of chronic physical training and acute intensive exercise on plasma fibrinogen levels and the relationship of these responses to beta-fibrinogen G-453-A polymorphism genotype. One hundred fifty-six male British Army recruits were studied at the start of their 10-week basic training, which emphasizes physical fitness. Cohorts were restudied between 0.5 and 5 days after a major 2-day strenuous military exercise (ME) undertaken in their final week of training. Changes in fibrinogen concentration were adjusted for the effects of age, body mass index, and smoking history. Compared with baseline values, fibrinogen concentrations were significantly lower (11.9%, P=.04) at day 5 after ME, consistent with the beneficial effect of training. However, they were higher on days 1 through 3 after ME (suggesting an "acute-phase" response to strenuous exercise) and were maximal on days 1 and 2 (27.2%, P<.001 and 37.1%, P<.001 respectively). Fibrinogen genotype was available in 149 individuals. As expected from previous studies, men with one or more fibrinogen gene A-453 alleles had plasma fibrinogen concentration slightly but significantly higher at baseline (4.5%, P=.11). During the acute-phase response (days 2 and 3), however, the degree of rise was strongly related to the presence of the A allele, being 26.7+/-5.4% (mean+/-SE), 36.5+/-11.0%, and 89.2+/-30.7 for the GG, GA, and AA genotypes, respectively (P=.01). These results confirm that chronic exercise training lowers plasma fibrinogen levels, that intensive exercise generates an acute-phase rise in levels, and that this acute response is strongly influenced by the G/A polymorphism of the beta-fibrinogen gene.

Adolescent↗
PubMed1995

Repair of anomalous pulmonary venous connection to the superior vena cava.

Complex forms of anomalous pulmonary venous connection to the superior vena cava (SVC) can be difficult to correct surgically. Since 1987, 11 patients have undergone repair of anomalous pulmonary venous connection to the SVC by diversion of the pulmonary venous drainage to the left atrium using a baffle with division of the SVC and reimplantation on the right atrial appendage to restore normal systemic venous drainage. Total anomalous pulmonary venous connection was present in 3 patients and partial anomalous pulmonary venous connection, in 8. All patients are alive and asymptomatic at a mean follow-up of 2.3 +/- 1.4 years. Postoperative echo-cardiograms (8 patients) revealed pulmonary venous obstruction requiring reoperation in 1 patient. No patient has clinical evidence of SVC obstruction, and all are in sinus rhythm. This is a safe and effective technique for repair of complex forms of anomalous pulmonary venous connection to the SVC, and the incidence of postoperative venous obstruction and rhythm disturbances is low.

Adolescent↗
PubMed1995

Hypertension trial results: consensus and conflicts.

In severe and accelerated hypertension the benefits of treatment are clearcut. In patients < 60 years of age with mild hypertension the main benefit is reduction of stroke by about 40%. The death rate from stroke is declining in many affluent countries for reasons which can only be partly explained by mass treatment of hypertension. In the MRC trial in patients < 60 years old it took 2500 patient/years of treatment to save one stroke. If the number of strokes is declining for other reasons the number of patient/years to save one stroke may be increasing. In older patients the absolute benefit is greater because they suffer more stroke events and because treatment also reduces coronary events.

Antihypertensive Agents↗
PubMed1995

Risk factors for ischaemic heart disease and stroke mortality in young and old hypertensive patients.

We investigated the predictors of cardiovascular mortality at different ages in a longitudinal study of 10186 hypertensive patients attending clinics in the UK. There were 7374 patients (51% were men) < 60 years of age and 2799 patients (44% men) were > or = 60 years. For IHD death the age-adjusted relative risks (RRs) and 95% confidence intervals (CI) for a 1 mmol/l increase in cholesterol were RR = 1.17 (1.07, 1.27) (men) and RR = 1.22 (1.12, 1.33) (women). The RRs for stroke were 0.99 (men) and 1.07 (women). In men and younger women, urea and smoking were important predictors of IHD and stroke death. Age differences were present in women for both urea and smoking. For IHD in women, smoking: RR = 2.65 (1.80, 3.89) (< 60 years) and RR = 1.38 (1.01, 1.88) (> or = 60 years). For stroke in women, smoking: RR = 2.03 (1.23, 3.35) (< 60 years) and RR = 1.06 (0.70, 1.61) (> or = 60 years). We conclude that urea and smoking are important risk factors for stroke and IHD death in hypertensive women aged < 60 years, but are less important in those aged over 60 years. Cholesterol predicted IHD death in all men and women, but did not predict stroke death.

Adult↗
PubMed1994

Optimism abounds.

Explore the source record for details and available documents.

Forecasting↗
PubMed1994

Role of endothelium in the maintenance of low pulmonary vascular tone in normal children.

BACKGROUND: Resting vascular tone is low in the normal pulmonary circulation, and experimental studies have suggested that this may be due to the continuous release of endothelium-derived nitric oxide (NO), a locally acting vasodilator. We have investigated whether NO contributes to the normal control of pulmonary vascular tone and resistance in children. METHODS AND RESULTS: We studied the hemodynamic effects of NG-monomethyl-L-arginine (L-NMMA), a specific inhibitor of NO synthesis, on the pulmonary circulation of six children 2 to 17 years old (mean, 9 years) with congenital heart disease but normal pulmonary blood flow, pressure, and resistance (all had isolated left heart obstructive lesions). The diameter of a segmental pulmonary artery and pulmonary blood flow velocity were measured by quantitative angiography and intra-arterial Doppler catheters. There was a consistent, dose-dependent fall in pulmonary blood flow velocity in response to three increasing doses of L-NMMA (compared with baseline, flow velocity fell to 75 +/- 7%, 62 +/- 8%, and 40 +/- 10%, P < .01). Flow velocity returned to control values with subsequent infusion of L-arginine, the substrate for NO. Thereafter, acetylcholine, an endothelium-dependent dilator, produced an increase in flow velocity (56 +/- 10% greater than baseline, P < .01). Arterial diameter was unchanged during L-NMMA and L-arginine infusions, indicating that the major effect of each agent is to alter vascular tone distal to the segmental pulmonary arteries. CONCLUSIONS: The dilator action of endothelium-derived NO contributes to the maintenance of low resting pulmonary tone in normal children. Impairment of NO production may contribute to the elevated pulmonary vascular resistance that complicates some cases of congenital heart disease.

Arginine↗
PubMed1991

Risks and benefits in the trial of the European Working Party on High Blood Pressure in the Elderly.

Hypertensive patients over the age of 60 years were admitted to a double-blind placebo-controlled trial. Patients in the actively treated group received a combined potassium-losing and -sparing diuretic (triamterene 50 mg plus hydrochlorothiazide 25 mg; n = 416); this dose could be doubled and methyldopa (up to 2 g, daily) was added in 35% of patients when blood pressure remained high. The placebo group (n = 424) received matching capsules and tablets. Adverse effects were assessed in the double-blind period of the trial by calculating the incidence of abnormal biochemical results, investigator reports of diseases and prescriptions of concomitant therapy and a self-administered symptom questionnaire completed by patients. In 1000 hypertensive subjects over 60 years of age, 1 year of active treatment would prevent 11 fatal cardiac events, 6 fatal and 11 non-fatal strokes and 8 cases of severe congestive heart failure. No unexpected adverse treatment effects were observed. A significant excess incidence rate (per 1000 person years) was found in the active group compared with placebo for: (1) impaired renal function, a serum creatinine greater than 180 mumol/l (2.0 mg/dl); (2) mild hypokalaemia, a serum potassium less than 3.5 mmol/l; (3) reports of gout; and (4) an elevated serum uric acid greater than 0.52 mmol/l in men or greater than 0.46 in women. Elevated blood sugar and prescriptions for hypoglycaemic drugs tended to be more frequent in the actively treated group, but this difference was not statistically significant. In both groups, there was a low incidence (less than 7 per 1000 person years) of anaemia and depression and diseases of the liver, gall bladder or pancreas.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Is a high serum cholesterol level associated with longer survival in elderly hypertensives?

The relationship between serum total cholesterol, measured at randomization, and mortality was investigated in 822 patients, who were followed for an average of 3.1 years in a double-blind trial, conducted by the European Working Party on High Blood Pressure in the Elderly. Serum cholesterol, measured at randomization, was 0.54 mmol/l higher in women than in men, and declined with increasing age in both men (0.028 mmol/l per year) and women (0.036 mmol/l per year). During follow-up on randomized treatment, cholesterol fell by a similar amount with placebo (0.11 mmol/l per year) and with active treatment (0.14 mmol/l per year). Active treatment consisted of hydrochlorothiazide (25-50 mg/day) plus triamterene (50-100 mg/day) with the addition of alpha-methyldopa (0.5-2.0 g/day) in one-third of the patients. Serum total cholesterol, measured at randomization, was independently and inversely correlated with total (P = 0.03), non-cardiovascular (P = 0.03) and cancer (P = 0.04) mortality during follow-up on double-blind treatment. Total and non-cardiovascular mortality were also negatively correlated with haemoglobin and body weight at randomization.

Aged↗
PubMed1990

Age-related effects of placebo and active treatment in patients beyond the age of 60 years: the need for a proper control group.

The age-related response to placebo and active antihypertensive treatment was evaluated in 742 elderly hypertensive patients who were followed in the double-blind placebo-controlled trial conducted by the European Working Party on High blood pressure in the Elderly (EWPHE). In the two treatment groups, the fall in systolic and diastolic blood pressures after 3 months was negatively correlated with age (P less than 0.02), indicating that the hypotensive effect of placebo and active treatment was more pronounced in older patients. Further comparison of the two treatment groups failed to demonstrate any statistical differences in the slopes of the hypotensive effect on age. These conclusions were not altered by cumulative adjustments for baseline blood pressure, pulse rate, serum creatinine and the presence of cardiovascular complications at entry. In conclusion, in the present study, a similar blood-pressure-lowering action which increased with age was observed on active and placebo treatment; thus, proof that an observed age-related hypotensive effect is caused by a particular drug requires comparison with a control group on placebo.

Aged↗
PubMed1989

Diuretic agents and beta-blockers in the treatment of hypertension.

Benzothiadiazine diuretic agents and beta-adrenergic receptor-blocking drugs are two of the main groups of drugs used to treat mild hypertension. Recently, questions have been raised about their relative efficacy in preventing morbidity and mortality from vascular disease in addition to their effect on lowering blood pressure. Attention has been focused on the unfavorable metabolic effects of diuretic drugs and the proven value of beta-adrenergic receptor blockade in secondary prevention after myocardial infarction. Four randomized controlled trials comparing drugs in these two classes have been published: the Medical Research Council trial, the International Prospective Primary Prevention Study in Hypertension, the Heart Attack Primary Prevention in Hypertension trial, and the Metoprolol Atherosclerosis Prevention in Hypertension study. These trials, especially that of the Medical Research Council, have raised some questions about the relative efficacy of these two classes of drugs in preventing stroke in smokers and nonsmokers. Overall, there is little evidence of a reduction in morbidity and mortality after myocardial infarction. The predicted advantage of beta-adrenergic receptor blockade over diuretic therapy has not been realized although there are sufficient hints of a differential benefit to encourage the performance of further trials.

Adrenergic beta-Antagonists↗
PubMed1988

The Medical Research Council Hypertension Trial: the smoking patient.

Tobacco smoking is a powerful risk predictor for coronary disease. In the recent Medical Research Council (MRC) Hypertension Trial, which this article discusses, it also proved to be an important predictor of stroke. The MRC trial had two active treatment groups, one of which received bendrofluazide and the other propranolol. The main positive result of the trial was a 45% reduction in stroke events in the actively treated groups. Propranolol appeared to be much less effective than bendrofluazide in the prevention of stroke in smokers, although both active drugs were equally effective in nonsmokers. Possible explanations for this lack of efficacy in smokers are discussed. Coronary events were not reduced by treatment, although there was a trend toward their reduction in nonsmoking men treated with propranolol. The lack of effect of propranolol in reducing coronary morbidity and mortality rates was a surprise in view of the positive results from trials with both short-term and long-term treatment with beta-adrenergic blockade after myocardial infarction.

Adult↗