A comparison of cardiac computerized tomography and exercise stress electrocardiogram test for the investigation of stable chest pain: the clinical results of the CAPP randomized prospective trial.

AIMS: To determine the symptomatic and prognostic differences resulting from a novel diagnostic pathway based on cardiac computerized tomography (CT) compared with the traditional exercise stress electrocardiography test (EST) in stable chest pain patients. METHODS AND RESULTS: A prospective randomized controlled trial compared selected patient outcomes in EST and cardiac CT coronary angiography groups. Five hundred patients with troponin-negative stable chest pain and without known coronary artery disease were recruited. Patients completed the Seattle Angina Questionnaires (SAQ) at baseline, 3, and 12 months to assess angina symptoms. Patients were also followed for management strategies and clinical events. Over the year 12 patients withdrew, resulting in 245 in the EST cohort and 243 in the CT cohort. There was no significant difference in baseline demographics. The CT arm had a statistical difference in angina stability and quality-of-life domains of the SAQ at 3 and12 months, suggesting less angina compared with the EST arm. In the CT arm, there was more significant disease identified and more revascularizations. Significantly, more inconclusive results were seen in the EST arm with a higher number of additional investigations ordered. There was also a longer mean time to management. There were no differences in major adverse cardiac events between the cohorts. At 1 year in the EST arm, there were more Accident and Emergency (A&E) attendances and cardiac admission. CONCLUSION: Cardiac CT as an index investigation for stable chest pain improved angina symptoms and resulted in fewer investigations and re-hospitalizations compared with EST. CLINICAL TRIAL REGISTRATION: http://www.controlled-trials.com/ISRCTN52480460.

The biochemical, physiological and psychological consequences of a "1,000 miles in 1,000 hours" walking challenge.

The combined effects of 42 days of chronic sleep disruption and repeated hourly bouts of physical exertion have not been described. This case study reports the physiological and psychological demands placed on one individual who walked 1 mile in each consecutive hour for a period of 1,000 h (42 days), covering a total distance of 1,000 miles. The participant walked at a mean speed of 1.75 m/s completing each mile in approximately 15 min. Over the course of the challenge, the individual lost 1.6 kg in body weight. Markers of skeletal muscle damage, increased gradually whilst free testosterone levels decreased over the course of the challenge. Stress hormones increased whilst inflammatory markers (CRP) initially rose but then returned towards baseline over the course of the study. Cognitive motor performance measured via reaction time was maintained throughout the 42 days. The participant also displayed mood states typical of an elite athlete at baseline and throughout the challenge. Participation in this novel '1,000 mile 1,000 h' walking challenge evoked considerable physiological stress in a fit, healthy middle-aged participant but did not markedly alter cognitive performance or mood over the 42-day period.

Gastrointestinal transit, post-prandial lipaemia and satiety following 3 days high-fat diet in men.

BACKGROUND/OBJECTIVES: High-fat (HF) diets of 2 weeks have been shown to accelerate gastric emptying (GE). To date, no studies have shown any alteration in GE following shorter HF diets. The aim of this study was to assess if an HF, high-energy diet of 3 days can adapt gastrointestinal (GI) transit, blood lipids and satiety. SUBJECTS/METHODS: Eleven male volunteers participated in a study consisting of three, 3-day interventions each separated by a test day. During the first intervention, volunteers recorded their diet. In the second and third interventions, volunteers repeated their food diary plus either a low-fat yogurt or HF yogurt supplement in randomized order. Test days involved measurement of GE using the (13)C octanoic-acid breath-test, mouth-to-caecum transit time (MCTT) using the inulin H(2) breath test and satiety using visual analogue scales. Blood samples for measurement of lipaemia were taken using a venous cannula. RESULTS: MCTT was different between the three test days (P=0.038), with the shortest MCTT following the HF intervention. GE was shortest following the HF intervention. There were no differences in satiety between the interventions. The HF intervention reduced triglycerides, total cholesterol and low-density lipoprotein cholesterol, and increased high-density lipoprotein cholesterol. CONCLUSION: This study shows that changes in GI transit owing to an HF diet can occur in a time period as short as 3 days.

The effects of ingesting a carbohydrate-electrolyte beverage 15 minutes prior to high-intensity exercise performance.

The aim of this study was to examine the effect of ingesting a commercially available carbohydrate-electrolyte (CHO-E) solution on strenuous exercise performance. Ten apparently healthy male volunteers (Mean +/- SD; age 20 +/- 2 yrs; height 178 +/- 7 cm; body mass 77 +/- 10 kg; estimated VO(2 max) 56 +/- 3 ml x kg(-1) x min(-1) completed three experimental trials in random order separated by a minimum of 7 days. For each trial, subjects consumed (8 ml x kg(-1) body mass) either a CHO-E solution (6% carbohydrate, 50 mg Na/500 ml), a non-CHO-E placebo, or no fluid, 15 minutes prior to exercise. The exercise involved intermittent shuttle (20 m apart) running for 1 hr followed by an incremental shuttle running test to exhaustion. Subjects displayed longer exercise times when the CHO-E solution was ingested compared with placebo or no fluid groups (exercise time to exhaustion - CHO-E 649 +/- 95 s, vs. placebo 601 +/- 83 s, vs. no fluid 593 +/- 107 s, P < 0.05). There was a main effect for time for specific gravity of urine (P < 0.05 vs. postexercise, pooled data) and body mass (P < 0.05 vs. postexercise, pooled data). The main finding from this investigation indicates that drinking a CHO-E solution 15 minutes prior to exercise improves performance. This study has practical implications for those sports where drinking during activity is restricted.

Measurement of serum albumin by capillary zone electrophoresis, bromocresol green, bromocresol purple, and immunoassay methods.

BACKGROUND/AIMS: The introduction of capillary zone electrophoresis (CZE) to this laboratory has highlighted discrepancies in albumin measured on an Abbott Aeroset by bromocresol green (BCG) and that calculated by CZE on the basis of total protein measured by Biuret. METHODS: This study examined differences in albumin estimation by CZE, Abbott Aeroset BCG, and Aeroset bromocresol purple (BCP), and compared these with albumin estimated by Beckman Array immunoassay. RESULTS: Altman and Bland analysis of results showed a positive bias of BCG with CZE (4.51 g/litre; 95% limits of agreement, 3.77 to 5.26; n = 72) and BCP (3.85 g/litre; 95% limits of agreement, -1.42 to 9.12; n = 72). CZE and BCP agreed closely (0.67 g/litre; 95% limits of agreement, -4.39 to 3.06; n = 72). Analysis of 57 of those samples in which BCG and CZE differed > or = 5 g/litre showed a positive bias of BCG with immunoassay (8.35 g/litre; 95% limits of agreement, 1.54 to 15.16; n =57), with good agreement between CZE and immunoassay (-0.44 g/litre; 95% limits of agreement, -2.82 to 1.94; n = 57). CONCLUSIONS: BCP is superior to BCG for the assay of albumin and has replaced BCG as the routine test for albumin in this laboratory.

Physical fitness, lipids, and apolipoproteins in the Northern Ireland Health and Activity Survey.

The objective of this study was to investigate the relationship between physical fitness, lipids, and apolipoproteins in a cross-sectional study using a two-stage probability sample of the population of Northern Ireland. The main outcome measures were physical fitness using VO2max estimated by extrapolation from submaximal oxygen uptake while walking on a motor driven treadmill, and total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, HDL2 and HDL3, and Lp(a). There were no significant relationships with fitness, after adjustment for possible confounders, with the exception of a positive relationship with HDL2 in males (P < or = 0.01) and Lp(a) in females (P < or = 0.05). There was also a relationship between physical fitness and HDL:apo AI ratio in males and females after adjustment for possible confounders (P < or = 0.05). We concluded that there were few relationships between lipid parameters and physical fitness after adjustment for possible confounders. The relationship between physical fitness and Lp(a) in females suggests a benefit associated with physical fitness and the relationship between physical fitness and HDL:apo AI ratio was in keeping with improved HDL cholesterol transport.

APO E genotype and familial hypercholesterolaemia.

Apolipoprotein E genotypes were measured in 83 patients with familial hypercholesterolaemia (FH) and in 175 blood donor controls. Following DNA extraction from peripheral blood, each sample was genotyped for the Apo E polymorphism by polymerase chain reaction. No significant differences were found in the levels of the epsilon 2 and epsilon 3 alleles between the two groups, while the epsilon 4 allele was approximately twice as prevalent in the FH patients as in controls (P = 0.006, df = 1). Of the FH patients, 8.4% were homozygous for the epsilon 4 allele while this genotype was rare in controls (P = 0.009, df = 1). These results suggest that the epsilon 4 allele is over represented in the FH population and may contribute to increased cholesterol levels and consequent vascular disease.

Systemic lytic state is not a predictor of coronary reperfusion in acute myocardial infarction.

To investigate why approximately one third of patients thrombolysed with streptokinase fail to reperfuse, we assessed the lytic status, antistreptokinase antibody and non invasive parameters of reperfusion in 95 consecutive patients with acute myocardial infarction treated with streptokinase for the first time. The lytic status was assessed by Clauss fibrinogen assay and thrombin clotting time before and 2 h after streptokinase infusion. Antistreptokinase antibody was measured prior to the infusion. Reperfusion was assessed by measurement of the 24:96 h troponin-T ratio (a ratio > 1 indicating reperfusion) and ST segment resolution 2 h post streptokinase. Ninety-two (97%) patients achieved a systemic lytic state with a fibrinogen titre of less than 1.0 g/l and thrombin clotting time ratio of > 2.5. Despite this, 27% failed to reperfuse with a mean 24:96 h troponin-T of 0.9, SD 0.6 vs. 3.4 +/- 3.2 in the reperfused group, (P < 0.0001). 83% of the reperfused group but none of the non reperfused group had ST segment resolution. No difference was observed in the levels of fibrinogen and thrombin clotting time between the reperfused 0.25 +/- 0.3 g/l; 6.9 +/- 4, and the non reperfused group 0.4 +/- 0.6 g/l; 7.9 +/- 2.6. No difference was observed in the levels of antistreptokinase antibody between the reperfused (median = 168 U/ml and the non reperfused (median = 177 U/ml). Failure to reperfuse with Streptokinase is not due to failure to achieve a lytic state. Therefore increased or accelerated dosages of streptokinase are unlikely to increase the rate of reperfusion.

Physical activity, lipids, apolipoproteins, and Lp(a) in the Northern Ireland Health and Activity Survey.

In a cross-sectional study using a two-stage probability sample (N = 1,600) of the population of Northern Ireland, there was an inverse association between the highest recorded recent activity and total cholesterol (P < or = 0.01), LDL (P < or = 0.01), triglyceride (P < or = 0.05) and Chol:HDL ratio (P < or = 0.001) in males, and total cholesterol (P < or = 0.001), LDL (P < or = 0.001), and triglyceride (P < or = 0.01) in females; between habitual activity and HDL (P < or = 0.05) in males and total cholesterol (P < or = 0.05) and triglyceride (P < or = 0.01) in females. There was a relationship between the highest recorded activity and apoAI (P < or = 0.01) and apoB (P < or = 0.01) in males and with apoB (P < or = 0.001) in females; between habitual activity and apoAI (P < or = 0.01) and apoAII (P < or = 0.05) in males and apoB (P < or = 0.01) in females; between past activity and Lp(a) in females (P < or = 0.05). After adjustment for possible confounding factors, total cholesterol (P < or = 0.05) and LDL (P < or = 0.05) were unexpectedly higher in males who were active throughout life. Total cholesterol (P < or = 0.05) and LDL (P < or = 0.001) were higher in females with highest recorded activity and triglycerides lower (P < or = 0.05) in those habitually active. An association between highest recorded activity and apoAI (P < or = 0.01), and past activity and apoAI:apoB ratio (P < or = 0.05) was shown in males and in females, after adjustment, and between apoB (P < or = 0.05) and highest recorded activity.

Vitamin E and exercise in the Northern Ireland population.

Serum vitamin E, vitamin E/cholesterol and physical activity and fitness were examined in a representative cross section (n = 1600) of the Northern Ireland population as part of the Northern Ireland health and activity survey. Serum vitamin E levels were measured by high-performance liquid chromatography, cholesterol by an enzymatic method, physical activity profile was recorded by computer assisted interview and physical fitness was determined by estimation of VO2 max. The levels of serum vitamin E and vitamin E/cholesterol ratio in the Northern Irish population were similar or higher than in other populations with lower incidences of coronary heart disease. The assessment of activity showed that 75% of the population fell below recommended activity levels likely to confer a cardioprotective effect. A significant relationship (P = 0.01) was found in males between serum vitamin E levels and lifetime participation in physical activity. Otherwise no relationship was found between serum vitamin E or vitamin E/cholesterol ratio and physical activity or fitness in the population.

Total radical trapping antioxidant potential (TRAP) and exercise.

The relationship between physical activity, physical fitness and total radical trapping antioxidant potential (TRAP) was examined in the Northern Ireland Health and Activity Survey. This was a cross-sectional population study (n = 1600) using a two-stage probability sample of the population. TRAP was calculated using the sum of the individual serum antioxidant concentrations (urate, protein thiols, ascorbate, alpha tocopherol and bilirubin) multiplied by their respective stoichiometric values. Physical fitness was determined by estimation of VO2max by extrapolation from submaximal oxygen uptake, and physical activity was recorded by computer-assisted interview. Mean serum TRAP concentrations were significantly higher in males (653 +/- 8.2 mumol/l, mean +/- SEM) compared to females (564 +/- 8.0 mumol/l) (p < 0.0001). Both male and female smokers had significantly lower TRAP values than non-smokers (males p < 0.0001, females p = 0.02). In females, there was a positive relationship of TRAP with age (p < 0.001) and body mass index (p < 0.001) but a negative relationship with physical fitness (p < 0.05). The known beneficial effects of exercise and activity do not appear to be directly mediated through increased antioxidant status.

Validation of an ion selective electrode system for the analysis of serum fluoride ion.

A high impedance unit was developed for use with a fluoride/pH electrode system for the measurement of serum fluoride. The linearity, accuracy, precision and detection limit of the system is reported. At a pH of 1.55, the system was linear over a range of serum fluoride concentrations up to 100 mumol l(-1), with a lower limit of detection of 0.3 mumol l(-1). Recoveries at this pH were 94-105% in the range 2.6-100 mumol l(-1). Within-run CVs ranged from 4.2% at a level of 2.3 mumol l(-1) to 1.2% at a level of 55.7 mumol l(-1), while day-to-day CVs ranged from 12.8% at a level of 2.2 mumol l(-1) to 4.6% at a level of 51.7 mumol l(-1). The system demonstrated a rapid response time and has the potential for a smaller sample size requirement with alternative electrode shape. Continued development of this unit into an automated fluoride ion selective electrode system is recommended, since the measurement of serial serum fluoride samples is of greatest importance in assessing the impact of new anaesthetic agents on renal function.

Ascorbate and exercise in the Northern Ireland population.

The relationship between physical activity, physical fitness and serum ascorbate was examined in the Northern Ireland Health and Activity Survey. This was a cross sectional population study (n = 1600), using a two stage probability sample, of the population of N. Ireland. Physical activity profile was recorded by computer assisted interview and physical fitness was determined by estimation of VO2 max by extrapolation from submaximal oxygen uptake. Serum ascorbate was measured using a colorimetric reaction of 2,4 dinitrophenylhydrazine with dehydroascorbate. Mean serum ascorbate was greater in females than males (p < 0.001), and was lower in smokers than non-smokers in both males (p = 0.01) and females (p < 0.001). There was no statistically significant relationship between serum ascorbate and age, social class, body mass index, physical activity or physical fitness in males but there was a relationship with age (p < 0.01) and physical fitness (p < 0.05) in females.

Increased serum apolipoprotein(a) in patients with chronic renal failure treated with continuous ambulatory peritoneal dialysis.

Patients with end-stage renal failure (ESRF) on renal replacement therapy are at significantly increased risk of cardiovascular disease. To determine whether altered concentrations of apolipoprotein(a) (apo(a)), the plasminogen-like protein moiety of the atherogenic particle lipoprotein(a), contributed to this increased risk, apo(a) concentrations were measured in 48 non-diabetic patients with ESRF treated by continuous ambulatory peritoneal dialysis (CAPD) therapy and compared with 65 controls. Apo(a) concentration was increased in CAPD patients compared to controls (geometric mean 419 units/l versus 137 units/l; ratio of means 3.06 (95% CI 1.95-4.80). We conclude that CAPD patients have increased apo(a) concentrations which may contribute to their increased risk of cardiovascular disease.

Experience of a quality assessment scheme for non-laboratory glucose meters.

In late 1989 a quality assessment scheme was introduced for glucose meters at 12 non-laboratory sites in a unit of management. The overall monthly imprecision of the meters varied from 3.4% to 17.1%, the highest coefficients of variation being recorded for glucose concentrations outside the range 3-20 mmol/l. In the same period 37% of results fell outside +/- 10% of laboratory set target limits; 13% fell outside +/- 20% of these limits. Participants have been advised of the unreliability of results outside the range 3-20 mmol/l. The main benefit of the scheme has been the improved confidence of users in the results obtained.