Edwin R. Nye

Lecithin:cholesterol acyltransferase activity, plasma and lipoprotein lipids and obesity in men and women

Lecithin:cholesterol acyltransferase (LCAT) activity, lipid concentration, lipoprotein lipid concentrations and cholesteryl ester linoleic acid proportion were determined in the plasma of 85 subjects randomly selected from a population during a health screen survey. Mean fractional LCAT rate was significantly higher in men than in women. Molar LCAT rate correlated with low density lipoprotein (LDL) cholesterol concentration in men and with nearly all lipoprotein lipid concentrations in women. Most of these relationships were dependent on plasma unesterified cholesterol (UC) concentration. Fractional LCAT rate was correlated only with HDL cholesterol concentration in women and this relation was dependent on the influence of obesity. An inverse relationship between plasma cholesteryl ester (PCE) linoleic acid proportion and molar LCAT rate in women was also explained by influences of obesity on the data. Both fractional and molar LCAT rates were positively correlated with obesity (Quetelets Index and subscapular skinfold thickness) in women but not in men. This study showed the influence of sex on nearly all correlations involving LCAT activity in combined groups of men and women.

Red blood cell cholesterol levels, plasma cholesterol esterification rate and serum lipids and lipoproteins in men with hypercholesterolaemia and normal men during 16 weeks physical training☆

Abstract Eight men with hypercholesterolaemia and 10 normal men participated in a 16-week physical training programme. Red blood cell cholesterol (RBC-C) levels, plasma cholesterol esterification rate (CER), serum lipoprotein lipid concentrations and dietary intake were measured during the programme. Whilst mean plasma CER was not significantly different between patients with hypercholesterolaemia and normal men, the mean fractional plasma cholesterol esterification rate was significantly lower in the patients throughout the study. Plasma CER increased and RBC-C levels decreased significantly in both the patients and the normal men. These changes were inversely correlated in the normal men. Serum cholesteryl esters and low density lipoprotein cholesterol (LDL-C) increased with training, particularly in the patients. Our results in normal men are consistent with the concept that the lecithin: cholesterol acyltransferase (LCAT) enzyme is involved in the transport of cholesterol from peripheral cells in vivo.

IDL Composition and Angiographically Determined Progression of Atherosclerotic Lesions During Simvastatin Therapy

Some patients with coronary artery disease experience continued progression of one or more coronary lesions despite treatment with drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and markedly lower plasma cholesterol levels. We examined relationships between the progression of coronary artery lesions and plasma lipoproteins, in particular intermediate density lipoprotein (IDL) and its composition, in 38 patients with coronary artery disease who had been treated with simvastatin for 2 years. Patients were given lipid-lowering dietary advice; 3 months later they were started on simvastatin therapy (10 mg/d) for 1 month, and after review of their plasma cholesterol levels, the dose was increased to 20 mg/d and later to 40 mg/d if the target level of plasma cholesterol had not been attained. Progression of lesions was determined by serial quantitative coronary angiography (variability of 5.5%) and was defined as an increase in percent diameter stenosis (%S)> or =10%; regression was defined as a decrease in %S > or =10%. The proportions of cholesteryl esters (CEs) and free cholesterol decreased significantly (P<.001), and proportions of protein and triglycerides increased significantly (P<.001) in IDL during simvastatin therapy. The CE content of IDL decreased significantly (-7.2 weight [wt]%, n=20, P<.001) in nonprogressors (patients who did not show progression of any lesions) and did not change significantly (-1.8 wt%, n=14, P=.36) in progressors (patients who showed progression of one or more lesions without regression of any lesion). This decrease in IDL CE content in nonprogressors was significantly (P=.01) different compared with the corresponding change in patients classified as progressors. Mean plasma cholesterol concentration tended to increase in progressors (0.47 mmol/L) and tended to decrease in nonprogressors (-0.39 mmol/L) during the initial 3-month diet period, and these changes were significantly different (P=.02). Furthermore, this change in plasma cholesterol level during the initial diet period was correlated significantly with the change in IDL CE content during the entire study (r=.348, n=38, P=.03). These data suggest that IDL CE content may be a determinant of progression of coronary lesions and may be influenced by compliance with or metabolic response to lipid-lowering dietary advice in patients with coronary artery disease during simvastatin treatment.

Plasma noncholesterol sterols in male distance runners and sedentary men.

SummaryPlasma lathosterol concentration is taken to be an index of the rate of cholesterol synthesis and plasma concentrations of plant sterols just as campesterol and betasitosterol are taken to be indeces of cholesterol absorption efficiency. These noncholesterol sterols were measured in plasma from 14 male distance runners and 10 sedentary men. Plasma lathosterol concentration was 30% lower (P<0.02) and plasma betasitosterol concentration was 33% higher (P<0.02) in the runners compared to the sedentary men. Plasma concentrations of lathosterol and plant sterols were inversely and significantly (P<0.05) correlated in both the runners and the sedentary men. Plasma plant sterol concentrations were correlated positively and significantly (P<0.01) with plasma high density lipoprotein cholesterol (HDL-C) concentrations in the runners and sedentary men combined. These findings suggest that more efficient cholesterol absorption may lead to higher plasma plant sterol concentrations and may contribute to lower cholesterol synthesis rates, reduced concentrations of plasma lathosterol and higher plasma HDL-C concentration in distance runners.

Community-Based Cardiac Rehabilitation Maintenance Programs: Use and Effects

BACKGROUND Cardiac rehabilitation (CR) graduates are encouraged to attend maintenance programs to promote long-term physical activity and preserve gains in function. This study describes the characteristics, attendance and physical function of community-based maintenance CR participants, compared to primary prevention participants. METHODS In this cross-sectional study, participants from two programs in New Zealand completed an interview, anthropometry, functional assessments (walking tests, chair stand test, handgrip strength), a 12-month physical activity recall, and a cardiopulmonary exercise test (subsample only). Attendance was ascertained from club records. RESULTS Participants (n=101, 55.4% Secondary Prevention) attended 37.4±27.9% of sessions annually. Participants were predominately New Zealand-European (93.5%), retired (80.2%), married (68.3%) elderly individuals, with musculoskeletal problems (60.0%), who lived proximate to the clubs. In Secondary but not Primary Prevention participants, first-year attendance was strongly correlated with attendance in subsequent years (p<0.001). In all participants, greater attendance in the previous 12 months was significantly associated with lower waist circumference, and greater shuttle walk test duration, chair stands and balance (p<.05). Session attendance was positively correlated to peak oxygen consumption (p=0.041) in Secondary Prevention participants only. CONCLUSION Participation in community-based CR maintenance programs is associated with health benefits but these programs are not accessed by a diversity of patients.

Estimating exercise capacity from walking tests in elderly individuals with stable coronary artery disease.

Abstract Purpose: Compared with symptom-limited cardiopulmonary exercise test (CPET), timed walking tests are cheaper, well-tolerated and simpler alternative for assessing exercise capacity in coronary artery disease (CAD) patients. We developed multivariate models for predicting peak oxygen consumption (VO2peak) from 6-minute walk test (6MWT) distance and peak shuttle walk speed for elderly stable CAD patients. Methods: Fifty-eight CAD patients (72 SD 6 years, 66% men) completed: (1) CPET with expired gas analysis on a cycle ergometer, (2) incremental 10-meter shuttle walk test, (3) two 6MWTs, (4) anthropometric assessment and (5) 30-second chair stands. Linear regression models were developed for estimating VO2peak from 6MWT distance and peak shuttle walk speed as well as demographic, anthropometric and functional variables. Results: Measured VO2peak was significantly related to 6MWT distance (r = 0.719, p < 0.001) and peak shuttle walk speed (r = 0.717, p < 0.001). The addition of demographic (age, gender), anthropometric (height, weight, body mass index, body composition) and functional characteristics (30-second chair stands) increased the accuracy of predicting VO2peak from both 6MWT distance and peak shuttle walk speed (from 51% to 73% of VO2peak variance explained). Conclusions: Addition of demographic, anthropometric and functional characteristics improves the accuracy of VO2peak estimate based on walking tests in elderly individuals with stable CAD. Implications for Rehabilitation Timed walking tests are cheaper, well-tolerated and simpler alternative for assessing exercise capacity in cardiac patients. Walking tests could be used to assess individual’s functional capacity and response to therapeutic interventions when symptom-limited cardiopulmonary exercise testing is not practical or not necessary for clinical reasons. Addition of demographic, anthropometric and functional characteristics improves the accuracy of peak oxygen consumption estimate based on 6-minute walk test distance and peak shuttle walk speed in elderly patients with coronary artery disease.

Linoleic acid and susceptibility to fatal ventricular fibrillation in rats

The effect of linoleic acid on the induction of fatal ventricular fibrillation by intravenous CaCl2 (10%), was studied in rats fed for a month from weaning on a diet with either a high or low content of linoleic acid. Studies were performed in the basal state and after pretreatment with noradrenaline, which increased the sensitivity to CaCl2 equally in animals from both diet groups. Despite considerable differences in the linoleic acid levels in the plasma and myocardium, the two groups did not differ in the incidence of fatal ventricular fibrillation. Our conclusions concerning the effect of linoleic acid on cardiac arrhythmias, and sudden death in particular, are compared with those from other studies.

Effects of community-based cardiac rehabilitation on body composition and physical function in individuals with stable coronary artery disease: 1.6-year followup.

Objective. To examine long-term changes in physical function and body composition in coronary artery disease (CAD) patients participating in ongoing community-based cardiac rehabilitation (CR). Design. Thirty-four individuals (69.7 ± 8.2 years; 79% men) participated in this longitudinal observational study. Baseline and follow-up assessments included incremental shuttle walk, short physical performance battery, handgrip strength, chair stands, body composition, last year physical activity, and CR attendance. Results. Participants attended 38.5 ± 30.3% sessions during 1.6 ± 0.2 year followup. A significant increase in 30-second chair stands (17.0 ± 4.7 to 19.6 ± 6.4, P < 0.001), body weight (75.8 ± 11.1 to 77.2 ± 12.1 kg, P = 0.001), and body fat (27.0 ± 9.5 to 29.1 ± 9.6%, P < 0.001) and a decline in handgrip strength (36.4 ± 9.4 to 33.0 ± 10.6 kg·f, P < 0.001) and muscle mass (40.8 ± 5.6 to 39.3 ± 5.8%, P < 0.001) were observed during followup. There was no significant change in shuttle walk duration. CR attendance was not correlated to observed changes. Conclusions. Elderly CAD patients participating in a maintenance CR program improve lower-body muscle strength but experience a decline in handgrip strength and unfavourable changes in body composition, irrespective of CR attendance.

The treatment of intermittent claudication with beta-pyridyl carbinol over two years

Abstract Forty-six patients with clinically significant peripheral atherosclerosis were randomly allocated into two groups; one receiving tablets of betapyridyl carbinol, up to 1800 mg daily, the other receiving a placebo. Patients were assessed clinically and their performance on a treadmill measured over intervals for two years. Plasma lipids were also measured. There was a slightly significant improvement in clinical findings after two years in those receiving drug treatment but no difference in symptoms. Treadmill performance appeared to improve equally in both placebo and drug treated groups. The plasma cholesterol fell significantly in the treated group compared the controls but the plasma triglycerides were not altered. Drop-outs from the trial did not differ significantly between the two groups. Two cases of hepatocellular dysfunction were attributable to betapyridyl carbinol.

The Great Malaria Problem

On 28 March 1895 Ross started for India on the P & O vessel Ballaarat. This was the beginning of his quest to solve the problem of the transmission of the malarial parasite. To use Ross’ words this was ‘thge great malaria problem’. He left full of evangelical zeal for the task and probably still under the considerable spell of Manson’s personality. Ross the poet and self-taught mathematician had, for the time, been eclipsed by Ross the scientist. He had armed himself with a microscope and used opportunities to examine the blood of fellow passengers and any available patients at hospitals at ports of call.