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Biomedical subjects

C Dore

Publications and source records attributed to C Dore.

At least 19 recordsLinked to original sources
PubMed2001

Effect of aging on the prognostic significance of ambulatory systolic, diastolic, and pulse pressure in essential hypertension.

BACKGROUND: This study compared the relative prognostic significance of 24 hour intra-arterial ambulatory systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and pulse pressure (PP) parameters in middle-aged versus elderly hypertensives. METHODS AND RESULTS: A total of 546 subjects aged <60 years and 142 subjects aged >/=60 years who had undergone baseline pretreatment 24-hour intra-arterial ambulatory blood pressure monitoring were followed for 9.2+/-4.1 years. Multivariate analysis showed that in younger subjects, 24-hour, daytime, and nighttime DBP, MAP, and SBP, when considered individually, were positively related to morbid events; DBP parameters provided the best predictive values. In the group >/=60 years (elderly group), 24-hour, daytime, and nighttime PP and SBP were the most predictive parameters, whereas ambulatory DBP and MAP measurements failed to provide any prognostic value. When 24-hour values of SBP and DBP were jointly included in the baseline model, DBP (z=2.02, P=0.04) but not SBP (z=-0.43, P=0.67) was related to outcome in younger subjects, whereas in the elderly group, SBP (z=3.33, P=0.001) was positively and DBP (z=-1.75, P=0.07) was negatively related to outcome. Clinic blood pressure measurements failed to provide any independent prognostic value in either age group. CONCLUSIONS: The relative prognostic significance of ambulatory blood pressure components depends on age; DBP parameters provided the best prognostic value in middle-aged individuals, whereas PP parameters were the most predictive in the elderly. This may reflect differing underlying hemodynamic mechanisms of hypertension in these age groups.

Adult↗
PubMed1999

Prediction of coronary and cerebrovascular morbidity and mortality by direct continuous ambulatory blood pressure monitoring in essential hypertension.

BACKGROUND: The goal of this study was to assess the prognostic value of ambulatory versus clinic blood pressure measurement and to relate cardiovascular risk to ambulatory systolic and diastolic blood pressure levels. METHODS AND RESULTS: The study population consisted of 688 patients 51+/-11 years of age who had undergone pretreatment 24-hour intra-arterial ambulatory blood pressure monitoring on the basis of elevated clinic blood pressure. A total of 157 first events were recorded during a 9.2+/-4.1-year follow-up period. The predictive value of a regression model containing age, sex, race, body mass index, smoking, diabetes mellitus, fasting cholesterol level, and previous history of cardiovascular disease was significantly improved by the addition of any ambulatory systolic or diastolic blood pressure parameter (whether 24-hour, daytime, or nighttime mean) or pulse pressure, whereas inclusion of baseline clinic blood pressure variables did not enhance the prediction of events. The most predictive models contained the ambulatory systolic blood pressure parameters. In the model containing 24-hour mean ambulatory systolic blood pressure (P=0.001), age (P<0.001), male sex (P<0.001), South Asian origin (P=0.008), diabetes mellitus (P=0. 05), and previous cardiovascular disease (P<0.001) were additional independent predictors of events. Whereas 24-hour ambulatory systolic blood pressure was linearly related to the incidence of both coronary and cerebrovascular events, 24-hour ambulatory diastolic blood pressure exhibited a positive linear relationship with cerebrovascular events but a curvilinear relationship with coronary events. CONCLUSIONS: Ambulatory blood pressure is superior to clinic measurement for the assessment of cardiovascular risk; there is no reduction in coronary risk at lower levels of ambulatory diastolic blood pressure.

Adult↗
PubMed1996

Value of thallium-201 imaging in detecting adverse cardiac events after myocardial infarction and thrombolysis: a follow up of 100 consecutive patients.

OBJECTIVE: To determine the prognostic role of thallium-201 imaging compared with that of exercise electrocardiography in patients with acute myocardial infarction treated by thrombolysis. DESIGN: Patients who remained free of adverse cardiac events six weeks after myocardial infarction had stress and rest 201TI imaging and exercise electrocardiography and were followed up for 8-32 months. Adverse cardiac events (death, reinfarction, unstable angina, and congestive heart failure) were documented. SETTING: Large district general hospital, Middlesex. SUBJECTS: 100 consecutive male and female patients who were stable six weeks after thrombolysis for myocardial infarction. MAIN OUTCOME MEASURES: Prediction of occurrence of adverse cardiac events after myocardial infarction by exercise cardiography and 201TI myocardial perfusion imaging. RESULTS: Reversible ischaemia on 201TI imaging predicted adverse cardiac events in 33 out of 37 patients with such events during follow up (hazard ratio 8.1 (95% confidence interval 2.7 to 23.8), P < 0.001). Exercise electrocardiography showed reversible ischaemia in 33 patients, of whom 13 had subsequent events, and failed to predict events in 24 patients (hazard ratio 1.1 (0.56 to 2.2), P = 0.8). CONCLUSION: 201TI imaging is a sensitive predictor of subsequent adverse cardiac events in patients who have received thrombolysis after acute myocardial infarction, whereas exercise electrocardiography fails to predict outcome.

Adult↗
PubMed1996

Epidemiology of gonococcal and chlamydial infections in Harrow and Brent.

OBJECTIVE: To describe the epidemiology and associated clinical features of gonorrhoea and chlamydial infection and to develop a profile of sexually transmitted diseases (STDs) in an outer London health district. DESIGN: Hospital-based retrospective study. SETTING: Genitourinary medicine clinic, Northwick Park Hospital, Harrow and Brent Health Authority. SUBJECTS: 70 male and female individuals with gonorrhoea and 129 with chlamydial infection, diagnosed consecutively over 28 months in 1992-94. RESULTS: More men than women had gonorrhoea (43 versus 27) but more women than men had chlamydial infection (84 versus 45), p < 0.001. There was a clear tendency for cases with either infection to locate along major road and rail transport routes. Foci of gonococcal infection were concentrated mainly in the densely populated areas, whereas chlamydial cases were more evenly spread. There was no significant effect of gender or type of STD on the odds ratio for residence in Harrow, single marital status or attendance for test of cure. However, the odds ratios for women having sexual intercourse with a regular partner only or previous STD were 5 (95% CI 2.4 to 10.2), p < 0.001 and 0.3 (95% CI 0.18 to 0.69), p = 0.002 times the odds for men, respectively. The odds ratios for patients with gonococcal infection being employed or having sex with a regular partner only were 0.5 (95% CI 0.27 to 0.98), p = 0.04 and 0.30 (95% CI 0.15 to 0.60), p < 0.001 times the odds for patients with chlamydial infection, respectively. Of the women with gonorrhoea and previous pregnancy, 68% gave a history of abortion compared with 44% of those with chlamydial infection (p = 0.03). CONCLUSION: The identification of foci gonococcal and chlamydial infection and apparent location of these infections along the major transport routes in our health district require further study. That chlamydial infection, unlike gonorrhoea, is evenly distributed irrespective of population concentration and deprivation, suggests urgent need for a comprehensive local effort to control both STDs.

Adult↗
PubMed1991

Effect of exposure to high pressure on subsequent spatial learning and memory in rats.

The effects of high helium pressure on the subsequent acquisition of spatial memory were studied in male rats. Thirty-two rats were exposed to 65 ATA helium-oxygen pressure for 4.2 days, decompressed (total time in chamber 5 days), and then tested in an eight-arm radial maze. Thirty-two control rats were exposed in the chamber to 1 ATA air. Each rat had 20 sessions in the maze (2 sessions/day for 10 days), and the number of correct (visiting an arm not previously visited to obtain the reward pellet) and incorrect choices (visiting a previously visited arm) were recorded. Statistical analysis showed that the rats exposed to 65 ATA performed significantly better than 1-ATA controls during the first 8 of 20 sessions. This effect was most pronounced in sessions 5-8. Results for sessions 9-20 showed that the pressure-treated rats still made more correct choices but to an extent that did not always reach statistical significance. Possible explanations include the pressure-treated rats performing better because of hunger after a lower food consumption at pressure. Alternatively, pressure itself may enhance proposed mechanisms of spatial memory such as long-term potentiation.

Animals↗
PubMed1988

Respiratory criteria of fitness for surgery and anaesthesia.

A retrospective analysis has been undertaken of 53 operations in 42 patients with severe chronic obstructive airway disease. All patients had a forced expiratory volume in 1 second between 0.3 and 1 litre, but the outcome of surgery was successful after their first operations, all of which were elective; 38 of the 42 had uneventful anaesthesia and surgery together with a normal postoperative period, while four had artificial ventilation of the lungs. The best predictors of the use of postoperative ventilation were the arterial PO2 and whether the patient was dyspnoeic at rest.

Aged↗
PubMed1987

Energy expenditure of agricultural workers in an area of endemic schistosomiasis in the Sudan.

Indices of physiological performance in the field under natural working conditions were measured in 46 Sudanese Gezira villagers and related to exercise performance under controlled laboratory conditions. The effect of Schistosoma mansoni infection on energy expenditure in the field was also investigated. A highly significant positive association between the maximal aerobic power output (VO2 max) measured in the laboratory with energy expenditure in the field (r = + 0.51, p less than 0.001) and with changes in body weight during work (r = 0.41, p less than 0.01) was found. The villagers' energy expenditure in field work amounted to 25-28 KJ/min, which corresponded to more than 50% of their predicted VO2 max. They maintained that relative work level for more than an hour. The differences in energy expenditure between moderately infected and non-infected villagers with schistosomiasis did not attain statistical significance but the number of non-infected subjects on which the comparison was based was small.

Adolescent↗
PubMed1986

A comprehensive clinical validation of the nuclear stethoscope.

Five studies were conducted to examine the degree of variability to be expected during the use of the non-imaging nuclear probe (BIOS Inc.) under a variety of clinical conditions. Comparison of the ejection fraction (EF) readings between the nuclear probe and a gamma camera showed good agreement, with the nuclear probe tending to underestimate lower, and overestimate higher camera EF values [mean (S.D.) difference, 0.84% (6.06)]. A comparison of two nuclear probes showed a small mean (S.D.) difference of EF readings of 0.063% (2.26). EF readings obtained in normal subjects 6 weeks apart were reproducible and differed by a mean (S.D.) of 0.23% (4.42). The administration of placebo to 10 normal subjects followed by sequential measurements for 4 h produced EF changes large enough to mimic a clinical effect, the largest hourly change observed being 5.4%, indicating the need for strict placebo control in interventional experiments. Data on four patients with heart failure showed small non-significant EF changes in the 1 h after placebo administration but a wide intra-subject range of ejection time and time to peak filling measurements. This highlights the problem of accurate, reproducible cursor placement in such patients. The nuclear probe is a portable, low cost instrument which produces accurate EF measurements when compared with the gamma camera.

Adolescent↗
PubMed1986

2',5'-oligoadenylate synthetase induction in lymphocytes of patients with connective tissue diseases.

Spontaneous production of the interferon induced enzyme 2',5'-oligoadenylate synthetase (2',5'-A synthetase) was significantly greater in blood lymphocytes of patients with systemic lupus erythematosus (SLE), Behçet's syndrome, and rheumatoid arthritis than in control lymphocytes. Alpha interferon (IFN-alpha) induced comparable production of enzyme in normal, rheumatoid, and Behçet's lymphocytes, and reduced, but still appreciable amounts in SLE lymphocytes. Phytohaemagglutinin (PHA) did not induce enzyme. Thus spontaneous production of 2',5'-A synthetase is encountered in several connective tissue diseases and seems likely to be induced by in-vivo exposure to interferons.

2',5'-Oligoadenylate Synthetase↗
PubMed1986

Left ventricular function during isometric hand grip and cold stress in normal subjects.

Both isometric exercise and cold stress have been suggested as alternatives to dynamic exercise for the detection of obstructive coronary artery disease. A non-imaging nuclear probe was used to measure left ventricular ejection fraction and relative left ventricular volumes continuously during both of these stress tests in 24 normal subjects. There was a significant fall in left ventricular ejection fraction within 15 seconds of subjects starting a two minute isometric hand grip test at 50% maximal voluntary contraction, with a mean (SE) maximal fall of 10% (1.8) after 90 seconds. During two minutes immersion of the hand and wrist in iced water left ventricular ejection fraction fell significantly within 30 seconds with a mean maximal fall of 7% (1.7) after one minute. Nine subjects underwent repeat tests under identical conditions approximately two weeks later. The standard error of the change in ejection fraction on two occasions was 5.4% at rest, 7.0% at the peak of isometric exercise, and 4.8% at peak cold stress. These results indicate that the reproducibility of both of these stress tests is acceptable when they are performed under carefully controlled conditions. The resulting changes in ejection fraction are transient, however, and moreover depend upon the choice of stress protocol. The discrepancies between published reports of such studies in coronary artery disease may be mainly due to methodological differences, and neither test is likely to be of sufficient discriminative ability to distinguish between individuals with obstructive coronary artery disease and normal subjects.

Adult↗
PubMed1985

Influence of dendritic cells on tumor growth.

Dendritic cells (DC) exposed to antigen are potent initiators of immune responses, and the numbers of DC and the dose of antigen control the level of response. The influence of these variables was tested on the growth of mouse sarcoma cells in vivo. When normal syngeneic DC (100,000) were given to mice with palpable tumors, tumor regression or delay in tumor growth was obtained. DC exposed to increasing doses of tumor extract in vitro before administration had progressively less effect. DC exposed to antigen delayed tumor growth significantly only when given on the same day as 500 tumor cells. The studies suggested that low doses of antigen on DC elicit immune responses and that high doses block them. The numbers of antigen-presenting cells and the dose of antigen modulate the degree of immunity to mouse sarcoma in vivo.

Animals↗
PubMed1983

Cardiac output and the recumbent position in late pregnancy.

Changes in cardiac output were measured by transcutaneous aortovelography in 30 pregnant patients and in 30 control subjects with change of position from the supine. When compared to the supine position, the left and right lateral and left 15 degrees tilt positions caused statistically significant increases in cardiac output, whereas the right 15 degrees tilt position did not. Neither fetal head engagement nor the time spent in each position had significant effects on the changes in cardiac output. It was not possible to identify a subgroup of pregnant patients who were particularly sensitive to changes in posture.

Adolescent↗
PubMed1980

Wholemeal bread and satiety.

Ten normal volunteers were offered unlimited amounts of bread, butter and jam at midday on four successive Tuesdays: on two days the bread was white (70 per cent extraction flour) and on the other two days it was wholemeal (100 per cent extraction flour). Contrary to previous reports, there was no significant effect of the type of bread on the quantity or type of nutrient intake at the meal, or in the subsequent 24 hours.

Adult↗
PubMed1977

Accidental hypothermia and impaired temperature homoeostasis in the elderly.

A longitudinal study of the age-related decline in thermoregulatory capacity was made in 47 elderly people to try to identify those at risk from spontaneous hypothermia. During the winters of 1971-2 and 1975-6 environmental and body temperature profiles were obtained in the home, and thermoregulatory function was investigated by cooling and warming tests. Environmental temperature and socioeconomic conditions had not changed but the body core-shell temperature gradients were smaller in 1976, indicating progressive thermoregulatory impairment. People at risk of developing hypothermia also seem to have low resting peripheral blood flows, a nonconstrictor pattern of vasomotor response to cold, and a higher incidence of orthostatic hypotension.

Aged↗
PubMed1975

Water balance and body weight: studies in a tropical climate.

Total body weight, water balance and energy balance were estimated in young adult men in a hot climate, over three 6-day periods. The aim was to determine the relative contributions to body weight changes of fluctuations in water and energy stores. In these subjects, the small observed body weight changes were due almost entirely to water balance changes. Water balance was regulated to within +/- 1% of body weight from day-to-day.

Adult↗