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Biomedical subjects

D J Mertens

Publications and source records attributed to D J Mertens.

13 recordsLinked to original sources
PubMed2000

14q terminal deletion: prenatal diagnosis in a child with severe congenital anomalies.

A fetal patient presented at 27.3 weeks of gestation with polyhydramnion. Ultrasound examination showed enlarged cerebral ventricles, abnormal position of the fingers and abnormal external genitals. Chromosome studies in chorionic villus material were normal male: in cultured amniocytes a distal deletion 14q32 was demonstrated and confirmed by FISH analysis. The baby was born at 37 weeks and died spontaneously during labour. This is the first report of prenatal diagnosis of a terminal 14q deletion.

Abnormalities, Multiple↗
PubMed1998

Exercise without dietary restriction as a means to long-term fat loss in the obese cardiac patient.

BACKGROUND: To examine the effects of a 12-month daily walking program without dietary restriction on the metabolic rate, body composition and blood lipid profile of overweight and moderately obese patients following myocardial infarction. METHODS DESIGN: longitudinal training (preliminary study). SETTING: out-patient cardiac rehabilitation program. PARTICIPANTS: twelve consecutive volunteers (8M, 4F) with a body mass index of 25-40 kg/m2. Relative to average cardiac patients, the men but not the women were significantly heavier (100.8 vs 77.4 kg [M], 70.7 vs 74.2 kg [F]) and fatter (hydrostatic estimate of body fat 34.0% vs 23.1% [M]; 38.3% vs 36.3% [F]) than the general cardiac patient. MEASURES: body mass, hydrostatic weighing, triglycerides, total, HDL- and LDL-cholesterol, resting and peak oxygen intake, one week food intake diaries. RESULTS: Daily walking increased progressively from 20 min to 43 min over 3 months, and was then held constant for 9 months. Peak aerobic power increased 24%, from 19.9 to 24.6 ml/[kg.min] (p < 0.001). Resting oxygen intake rose from 3.1 to 3.4 ml/[kg.min], (p < 0.05). Energy intake increased from 6.10 to 6.57 MJ/day, but body mass decreased by an average of 4.5 kg (p < 0.05, 4.1 kg [M], 5.1 kg [F]), and body fat content diminished from 35.4 to 33.2% (p < 0.02, 1.8% [M], 3.2% [F]), with no change in lean body mass (57.7 vs 57.8 kg). Triglycerides diminished from 2.63 to 2.28 mmol/L (p < 0.005). Total and LDL-cholesterol also tended to change favorably (from 6.15 to 5.80 and 4.44 to 3.80 mmol/L respectively, but HDL-cholesterol was unchanged). CONCLUSIONS: A daily walking program without dietary restriction induces a favorable change in body composition and lipid profile in moderately obese cardiac patients. An exercise-induced increase of resting metabolism apparently makes an important contribution to this outcome.

Body Composition↗
PubMed1996

The place of perceived exertion ratings in exercise prescription for cardiac transplant patients before and after training.

OBJECTIVE: Heart rate provides a poor guide to exercise prescription after cardiac transplantation. This study explores whether the rating of perceived exertion (RPE) provides useful alternative information. METHODS: Borg's original categoric scale was applied to 36 male patients [T, age 47(SD 9 years] as they performed a progressive cycle ergometer test an average of seven months (range two to 23 months) after cardiac transplantation. The test was repeated after 16(7) months of progressive exercise centred rehabilitation. Sedentary but healthy controls [C, n = 45, age 45(7) years] performed a similar progressive cycle test. RESULTS: Initially, 13 RPE units corresponded to 66(12)% of peak VO2 in T and 50(11)% in C. Rehabilitation augmented peak VO2 (by 19%) and estimated lean body mass (by 3.5%) in the cardiac transplant patients. The increase of heart rate (HR) at 13 RPE units [delta HR = 10(17) beats.min-1] showed moderate correlations with gains of lean mass (r = 0.72) and gains of peak VO2 (r = 0.58). The relative oxygen intake at 13 RPE units remained unchanged at 68(12)% of peak VO2. CONCLUSIONS: Large inter-individual variations of RPE at a given VO2 limit the value of perceived exertion in exercise prescription. Ratings seem best restricted to fine tuning fixed distance/fixed speed exercise prescriptions in patients undergoing rehabilitation after cardiac transplantation.

Adult↗
PubMed1996

Quality of life and cardiorespiratory function in chronic heart failure: effects of 12 months' aerobic training.

OBJECTIVE: To examine the long-term benefits and safety of aerobic training in patients with chronic heart failure. DESIGN: Non-randomised control trial with 52 weeks follow up. SETTING: Outpatient cardiac rehabilitation referral centre. PATIENTS: Patients with compensated chronic heart failure (mean (SD) age 62 (6) years, New York Heart Association stage III, initial resting ejection fraction 22 (7)%). Experimental group of 17 men, 4 women; control group 8 men, 1 woman. INTERVENTIONS: Experimental group: progressive, supervised aerobic walking programme for 52 weeks. CONTROL GROUP: standard medical treatment. MAIN OUTCOME MEASURES: Six-minute walk distance, progressive cycle ergometer test to subjective exhaustion, disease-specific quality of life questionnaire, and standard gamble test, all measured at entry, 4, 8, 12, 16, 26, and 52 weeks. RESULTS: Control data showed no changes except a small trend to improved emotional function (P = 0.02 at 12 weeks only). Fifteen of the 21 patients completed all 52 weeks of aerobic training; two withdrew for non-cardiac reasons (16, 52 weeks). Three were withdrawn because of worsening cardiac failure unrelated to their exercise participation (4, 4, 8 weeks), and one had a non-fatal cardiac arrest while shopping (16 weeks). Gains of cardiorespiratory function plateaued at 16-26 weeks, with 10-15% improvement in six-minute walk, peak power output, and peak oxygen intake linked to gains in oxygen pulse and ventilatory threshold and reductions in resting heart rate. Marked improvements in quality of life followed a parallel course. CONCLUSIONS: Aerobic training is safe and beneficial in compensated chronic heart failure. Gains in aerobic function and quality of life persisted over a programme lasting 52 weeks.

Aged↗
PubMed1996

Nutritional, immunologic and psychological responses to a 7250 km run.

OBJECTIVE: Health, nutritional status, aerobic power, mood state and immune function were studied over 112 days of aerobic activity (a 7250 km cross-Canada run). TYPE OF STUDY CASE REPORT: a healthy nulliparous 43 yr old woman ran 65 km/day for 112 days at a 7.9 km/h pace. MEASURES: Food intake, Profile of Mood State and Beck Depression Inventory were monitored weekly. Resting lymphocyte subsets and cytokines were determined before the run, at 3324, 5700 and 7250 km, and after recovery. Clinical data, ventilatory threshold, maximal oxygen intake and immune responses to maximal exercise were obtained before and after the run. OBJECTIVE: Health, nutritional status, aerobic power, mood state and immune function were studied over 112 days of aerobic activity (a 7250 km cross-Canada run). TYPE OF STUDY CASE REPORT: a healthy nulliparous 43 yr old woman ran 65 km/day for 112 days at a 7.9 km/h pace. MEASURES: Food intake, Profile of Mood State and Beck Depression Inventory were monitored weekly. Resting lymphocyte subsets and cytokines were determined before the run, at 3324, 5700 and 7250 km, and after recovery. Clinical data, ventilatory threshold, maximal oxygen intake and immune responses to maximal exercise were obtained before and after the run. RESULTS: Early muscle pain was treated with Ibuprofen. A mild paronychia responded to saline soaks, and exercise-induced asthma necessitated inhalation of fenoterol hydrobromide, beclomethasone diproprionate and ipatropium bromide. Food intake, (16.7 MJ/day), was 4.3 MJ/day less than expenditure, covered by metabolizing 16.7 kg of tissue (81.4% fat, 18.6% lean tissue). Ventilatory threshold and aerobic power showed little change. Initial psychological data showed tension and lack of confidence. Depression increased when crossing the Rockies, and there was anger and lack of vigor after the event. The CD8 count was low throughout; the CD25 count increased, but the CD16/56 count, IL-6 and TNF-alpha decreased over the run. Three weeks later, IL-6 had increased, but TNF-alpha remained low. CONCLUSIONS: Given substantial fat reserves, an exercise-induced energy deficit of 4.3 MJ/day can be sustained for 112 days without significant adverse consequences for immune function.

Adult↗
PubMed1995

Personal health benefits of Masters athletics competition.

Questionnaires (750 respondents, 44.4% response rate) examined the long-term health value of endurance exercise training in older age-classed competitors ('Masters Athletes', 551 men and 199 women) over a 7-year period (1985-1992). The majority had initially completed maximal exercise tests. The weekly time devoted to training, competition and exercise-related travel was 10 to 30 h, and the annual expenditure on clothing, equipment and entrance fees was typically in the range Canadian $500-1500. Despite their age (mean(s.d.) 58(10), current range 40-81 years), only 1.4% reported sustaining a non-fatal heart attack and 0.6% had required bypass surgery over the 7-year interval. The majority (90%) were very interested in good health; 76% considered themselves as less vulnerable to viral illnesses than their peers, and 68% regarded their quality of life as much better than that of their sedentary friends. The majority of former smokers had stopped smoking before they began training, but 37% indicated that exercise had helped them in smoking withdrawal. In keeping with their health-conscious attitude, 59% had regular medical check-ups, and 86% obeyed legislation requiring use of a seat-belt when driving. In contrast with many older people, 88% slept well or very well. Slightly over half of the sample (57%) had sustained some injury which had limited their training for one or more weeks over the 7-year study. Although participation in Masters competition appears to carry considerable health benefits, gains may in part reflect an overall healthy lifestyle.

Adult↗
PubMed1994

A simple formula for the estimation of maximal oxygen intake during cycle ergometry.

Exercise prescription has traditionally been based on the heart rate/work rate relationship. Many post-myocardial (MI) patients are now taking medications such as beta-blockers that alter this relationship, necessitating an alternative method for exercise prescription. The directly measured maximal oxygen intake (VO2max) is not substantially affected by such medications, but direct determinations of VO2max are time consuming, costly, and vulnerable to both local muscle weakness and poor motivation. We have therefore re-examined the relationship between work rate and maximal oxygen intake in order to derive a simple formula which will give an indirect estimate of the latter. Our results, obtained on 28 patients receiving beta-blockers, 13 receiving calcium channel blockers, 10 receiving combined therapy, and 49 who received neither treatment, indicate that the peak oxygen intake can be estimated accurately, using the expression VO2max.ml.min-1 = 2W, where W is the peak power output, measured in kp.m.min-1, or 12.3 W, where W is the peak power output in Watts.

Exercise Test↗
PubMed1988

Cardiorespiratory responses to exercise training after orthotopic cardiac transplantation.

We have tested the feasibility and effectiveness of a 2 year (average 16 +/- 7 months) walk/jog exercise program on 36 male orthotopic cardiac transplant patients (21 to 57 years old) seen initially 2 to 23 months after surgery. Comparison of initial exercise test results with those in 45 age-matched normal men showed the patients to have a lesser lean body mass (56 +/- 7 vs 63 +/- 8 kg, p less than .001), with a higher resting heart rate (104 +/- 12 vs 77 +/- 14 beats/min, p less than .001) and systolic (138 +/- 16 vs 129 +/- 17 mm Hg, p less than .001) and diastolic (95 +/- 14 vs 84 +/- 10 mm Hg, p less than .001) blood pressures. Peak power output was less than normal (101 +/- 27 vs 219 +/- 41 W, p less than .001), as was peak heart rate (136 +/- 15 vs 176 +/- 13 beats/min, p less than .001), peak oxygen intake (VO2max) (22 +/- 5 vs 34 +/- 6 ml.kg.min-1, p less than .001), and absolute anaerobic threshold (1.18 +/- 0.40 vs 2.04 +/- 0.40 liters.min-1, p less than .001). Peak ventilatory equivalent was higher (48 +/- 9 vs 37 +/- 61.1-1, p less than .001). Cardiac output (Q), as estimated by the CO2 rebreathing method, was slightly above normal at rest (p less than .01), but below normal at two submaximal work rates. The group's average weekly training distance was 24 km, with eight highly compliant patients progressing to 32 km or more weekly. After training, lean tissue increased (+2.4 +/- 3.1 kg, p less than .001), and resting values were reduced for heart rate (-4 +/- 11 beats/min, p less than .05), systolic (-13 +/- 20 mm Hg, p less than .001), and diastolic (-9 +/- 17 mm Hg, p less than .001) blood pressures. There were significant reductions in submaximal values for minute ventilation (VE), ratings of perceived exertion, and diastolic blood pressure at equivalent workloads. Peak values increased for power output (+49 +/- 34 W, p less than .001), VO2max (+4.0 +/- 6.0 ml.kg.min-1, p less than .001), VE (+20 +/- 20 l.min-1, p less than .001), and heart rate (+13 +/- 17 beats/min, p less than .001), and decreased for diastolic blood pressure (-8 +/- 15 mm Hg, p less than .001).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMedDate not supplied

Pregnancy outcomes of inmates in a large county jail setting.

The purpose of this study was to examine low birthweight (LBW) and fetal death rates for women incarcerated in a large county jail during their pregnancy. Additionally, medical and support services available to these inmates were reviewed. Jail records showed this population to be both medically and socially high risk. Analysis indicated that their LBW rate was statistically higher (p < 0.05) than that of the county or state, but comparable to a matched group residing in high-risk areas of the city in which many of these women resided. During the course of the study, numerous jail policies were identified which had the potential to negatively impact the health of these women and their pregnancy outcomes.

Adolescent↗
PubMedDate not supplied

Exercise training for patients with chronic atrial fibrillation.

BACKGROUND: Patients with atrial fibrillation (AF) referred for exercise rehabilitation exemplify the problem inherent in reliance on pulse rate to prescribe and monitor training intensity. METHODS: Exercise training was accomplished by specifying a training walking pace based on 60% to 80% of the peak oxygen intake (VO2max), as determined by the analysis of expired air (Horizon metabolic cart), and/or the ventilatory threshold (VT), together with a perceived exertion of 12 to 14 on the original Borg scale of perceived exertion. RESULTS: At the end of 1 year, a significant training effect was demonstrated (VO2max average increase 15%, 14.8 +/- 3.6 mL/kg/min to 17.0 +/- 3.6 mL/kg/min, P < .02; VO2 at VT, average increase 14%, 11.2 +/- 2.2 to 12.8 +/- 2.6 mL/kg/min, P < .01; peak power output increase 21%, 92.5 +/- 29.3 Watts to 112 +/- 3.7 Watts, P < .05) in a group of 20 patients (13 men, 7 women) with chronic atrial fibrillation. CONCLUSIONS: Patients with chronic atrial fibrillation can achieve significant functional gains from an exercise rehabilitation program.

Aged↗
PubMedDate not supplied

On the prediction of physiological and psychological responses to aerobic training in patients with stable congestive heart failure.

BACKGROUND: Physiological and psychological markers of patients with congestive heart failure (CHF) who will respond to aerobic training are needed as a guide to appropriate therapy. METHODS: Seventeen of 21 patients with stable CHF completed a 16-week supervised progressive walking program 5 times per week. Cycle ergometer determinations of peak oxygen intake and peak power output at entry and 16 weeks were supplemented by a 6-minute walk, a disease-specific Quality of Life (QOL) questionnaire, and a standard gamble. RESULTS: Peak oxygen intake increased by 2.6 +/- 1.5 mL/(kgmin) over an initial value of 15.6 mL/(kgmin), with parallel gains in peak power and the 6-minute walk. Marked improvements in QOL and standard gamble scores also developed. Initial cardiorespiratory status (heart volume, ejection fraction, oxygen pulse, and peak oxygen intake) was correlated more closely (P = 0.09 to 0.18) with delta peak oxygen intake than with delta peak power or delta walking distance. Physiological gains bore little relationship to initial psychological status. Gains in CHF Questionnaire and Standard Gamble scores were strongly associated with initial scores for these variables (dyspnea, P = .02; mastery, P = .005; standard gamble, P = .001), but could not be predicted from either initial physiological status or gains in physiological condition. CONCLUSIONS: Initial cardiorespiratory status provides little indication of which patients with CHF respond well to training. Gains in QOL score are influenced by initial scores, and seem to show a "ceiling" effect.

Aged↗
PubMedDate not supplied

Risk profile and health awareness in male offspring of parents with premature coronary heart disease.

BACKGROUND: The offspring of parents who suffer from premature coronary heart disease have a significantly higher risk of early cardiac death than controls. A genetic predisposition is compounded by a commonality of environmental risk factors within families. Increasing awareness, early detection and modification of risk factors are essential components of an effective public health strategy to protect this highly vulnerable population. METHODS: The sons (n = 571) of parents with premature coronary heart disease attended the Toronto Rehabilitation Centre for a risk factor evaluation that included an interview with questionnaire, measurement of body dimensions and blood lipids, and cardiopulmonary exercise testing. A follow-up questionnaire was sent out 2 years after the evaluation. RESULTS: Despite concern about family history, 23% of subjects were smokers and 75% were inactive. Objective data confirmed a substantial prevalence of cardiac risk factors: less than optimal cardiovascular fitness (48%), overweight (34%), total cholesterol > or = 200 mg/dL (46%), high-density lipoprotein cholesterol < or = 35 mg/dL (26%), low-density lipoprotein cholesterol > or = 160 mg/dL (16%), triglycerides > or = 200 mg/dL (27%), and lipoprotein (a) > 30 mg/dL (24%). Although almost all had a family physician whom they had seen an average of 1.8 times in the past year, and 4.7 times in the previous 3 years, screening and risk factor intervention strategies were disappointing. Two-year follow-up data showed a heightened health awareness, with a greater proportion of subjects exercising and attempting to maintain an appropriate body mass. CONCLUSIONS: The male offspring of parents who have suffered a premature coronary event exhibit a substantial prevalence of modifiable risk factors. The family physician can play an essential role in promoting a healthy lifestyle through risk reduction counselling and screening.

Adult↗