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Biomedical subjects

F Landry

Publications and source records attributed to F Landry.

At least 37 records · Page 2Linked to original sources
PubMed1987

[Physical fitness improves after mitral valve replacement].

To determine whether women with mitral valve prostheses can improve their physical fitness without suffering cardiac dysfunction or hemolysis, 10 women (mean age 47 years) who had undergone mitral valve replacement (an average of 3.7 years earlier) were enrolled in an 8-week program of exercise on a bicycle ergometer. They exercised three times a week, starting at 60% and increasing to 80% of their maximal heart rate achieved during stress testing. Nine other women with similar clinical characteristics (mean age 48 years) constituted a control group. Exercise produced significant cardiovascular improvement, as evidenced by a mean decrease of 12 beats/min in the heart rate at steady-state work load (p less than or equal to 0.01), a mean increase of 121 kpm in the maximal tolerated work load (p less than or equal to 0.01), and a mean increase of 4 ml/kg X min-1 in the peak oxygen consumption (p less than or equal to 0.01). There was a small increase in the mean plasma hemoglobin level (15 to 29 mg/dl) and the mean reticulocyte count (1.8% to 2.4%) after the program (p less than or equal to 0.05). There were no significant changes in any of the variables studied in the control group. There were no changes in the clinical, electrocardiographic or echocardiographic findings in the experimental group. Although slightly increased hemolysis may occur, women with mitral valve replacement can improve their cardiovascular condition by exercising.

Erythrocyte Count↗
PubMed1987

Familial aggregation in physical fitness, coronary heart disease risk factors, and pulmonary function measurements.

In order to test for the presence of familial aggregation in physical fitness and coronary heart disease risk factors, body fat, submaximal power output, muscular strength, muscular endurance, blood pressure, pulmonary functions, and several blood biochemical variables were measured in 304 nuclear families living in the Quebec city area. Analysis of variance indicated a larger between-family than within-family variation for all the variables. When all members of nuclear families were considered, intraclass correlations ranged from 0.21 to 0.34 (P less than or equal to 0.01). Interclass correlations computed for various pairs of relatives revealed significant parent-child and sibling correlations for all the variables (0.14 less than or equal to r less than or equal to 0.55; P less than or equal to 0.01). On the other hand, spousal correlations tended to be lower but significant (0.10 less than or equal to r less than or equal to 0.30; P less than or equal to 0.05) for all variables except subcutaneous fat and hemoglobin concentration. These results suggest that heredity and common lifestyle shared by members of nuclear families are responsible for the familial aggregation of physical fitness, coronary heart disease risk factors, and pulmonary functions. The findings also support the notion of considering the nuclear family as a unit of intervention in the application of preventive measures aimed at the reduction of several risk factors.

Adolescent↗
PubMed1987

Silent ischaemia in post-infarction patients: a 21-month follow-up study.

The purpose of this study was to determine the prevalence of silent myocardial ischaemia (SMI) in post-infarction patients and to follow its clinical evolution in the course of a 21-month follow-up period. Of the 12,500 patients treated at the Klinik Roderbirken between Jan 1980 and Jun 1983 40% had angina. Three-vessel disease was documented in 61% of the 3150 subjects who had a coronary angiography. SMI identifiable on the exercise ECG was observed in 680 patients (5.4%). Sixth-three subjects (mean age 52 +/- 5.5 years) were selected and followed on the basis of stringent criteria. Prevalence of SMI at an average of 6 weeks after MI was 1/200 or 0.5% in that sample. Prognosis was good with a low mortality rate of 3.2% during the 21-month follow-up period. Factors weighing negatively on the observed SMI prognosis are the prevalence of 3-vessel disease (74%) and of pathological ejection fractions (52%) as well as the presence of ischaemia itself. Conversely, factors weighing positively on the observed SMI prognosis are the reasonably high exercise tolerance level (102 +/- 32 W), the low arrhythmogenic potential (73% less than or equal to Lown II), and the normal chest X-ray in more than 80% of the patients. In this study, 43% of the patients were felt to require angiography and only 10% were considered for bypass surgery. Good prognosis may be seen as a contra-indication for revascularization surgery. Yet, the prevalence of 3-vessel disease and the fact that 2/3 of the SMI subjects became symptomatic during the follow-up period are arguments in favour of early angiography.

Adult↗
PubMed1987

Filling pressures in post-myocardial infarction patients: comparison between isometric and dynamic exercise.

The purpose of this study was to determine if isometric exercise (handgrip) using a substantial muscle mass and intensity could be substituted for dynamic exercise in the assessment of left ventricular function in myocardial infarct (MI) patients. Forty patients with documented MI were assigned, on the basis of their previous exercise ECG responses, to either an exercise-induced ischaemic group (Group 1) or to a non-exercise ischaemic group (Group 2). Eight apparently healthy males served as controls. Pulmonary capillary pressure (PCP) was measured at rest, during volume loading and during isometric and dynamic exercise. Mean PCP in Group 1 increased progressively from 7.5 +/- 2.9 mmHg at rest, to 11.6 +/- 3.8 mmHg during volume loading, to 18.8 +/- 10.2 mmHg during the isometric exercise and to 25.2 +/- 10.1 mmHg during the dynamic exercises. For Group 2, the respective values were 9.6 +/- 6.3, 13.1 +/- 6.4, 18.7 +/- 13.7 and 18.4 +/- 9.8 and for the controls 8.9 +/- 1.9, 11.3 +/- 1.2, 13.3 +/- 3.3 and 11.8 +/- 3.6 mmHg. The results of this study indicate that isometric exercise of 50% MVC using both hands can adequately replace dynamic exercise in the diagnosis of left ventricular function in post MI patients.

Adult↗
PubMed1987

Exercise hypertension in the perspective of systemic arterial hypertension. An overview.

Systemic arterial hypertension is one of the most wide-spread diseases in the world. It is a chronic disease with a very long asymptomatic phase. At an estimated prevalence in the developed countries of 15 to 20%, it can be assumed that approximately 80% of men and 60% of women with hypertension are either unaware of their condition or are not treated adequately. These figures show that reliable diagnostic measures are needed to provide efficient detection of high blood pressure in a given population. In this regard, exercise testing has proven particularly well-suited. Using standardized ergometry, patients with latent, borderline or manifest hypertension can be identified. Exercise hypertension is defined on the basis of an abnormal blood pressure increase during physical exercise in persons with normal blood pressure at rest. Because of marked interindividual fluctuation in blood pressure, values measured at rest may be of only limited usefulness in the diagnosis of hypertension. In contrast, the blood pressure during dynamic exercise may be particularly informative with respect to probability of future development of manifest hypertension and treatment of high blood pressure. Long-term studies have shown that within five years up to one-third of patients with exercise hypertension develop manifest hypertension at rest. Based on the Canada Fitness Survey data indicating that about 2% of the population demonstrate exercise hypertension, it can be estimated that approximately 200,000 Canadians will develop manifest hypertension within five years. Similar statistics are also applicable for most of the developed countries of the world.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Exercise hypertension in healthy normotensive subjects. Implications, evaluation and interpretation.

Exercise hypertension, defined as a blood pressure response to a dynamic exercise stressor which is considered excessive to what is normally observed in a healthy population, is currently the subject of much discussion. This interest appears to be related to the recent concerns that are being expressed in the utilization of hypertensive drugs with respect to their long-term benefits and risks. I would seem that the proper selection of patients for drug therapy will become as important as the treatment itself, not only for clinical purposes but to insure the quality of life of a patient in the pursuit of his/her daily activities. Also, a number of retrospective studies have shown that an exaggerated blood pressure response to exercise in resting normotensive persons could be a useful indicator to assist in detecting those persons who may be on the way to developing sustained hypertension. The literature suggests that this is a tenable hypothesis but one that will require testing by prospective research. In this respect, it has been suggested that if the blood pressure response to a dynamic exercise in borderline or labile hypertensives is normal, it is possible to dismiss the diagnosis of hypertension, at least temporarily. However, if the blood pressure response is exaggerated, then the diagnosis of hypertension should be considered. In Canada, the Canadian Aerobic Fitness Test (CAFT) has been utilized to assist in detecting exercise hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Personality psychological correlates of blood pressure behavior. Group comparison of hypertensive, exercise hypertensive and normotensive heart patients].

It has been well established that individuals with exercise hypertension are at risk of subsequently developing manifest hypertension at rest. In this regard, there is little data available on psychological aspects which may be related to this transition. Accordingly, this study was undertaken to determine whether persons with exercise hypertension and those with manifest hypertension differ in personality traits. With the aid of a personality inventory (FPI-R), a comparative analysis of personality structure was carried out in 60 patients with coronary artery disease (20 with manifest hypertension, 20 with exercise hypertension and 20 normotensive patients). Three differing personality profiles were found. Hypertensive patients had above average values for inhibition, excitability, suffer from stress, psychosomatic complaints and emotional susceptibility; their values for contentment with life were below the average. Persons with exercise hypertension also had above-average values for excitability while normotensive individuals had higher values for extraversion. With regard to prevention of development of manifest hypertension, it would seem reasonable, in patients with exercise hypertension, to encourage the learning of stress management techniques to suppress excitability.

Adaptation, Psychological↗
PubMed1985

Cardiac dimension changes with endurance training. Indications of a genotype dependency.

We studied the sensitivity of cardiac structures to endurance training. To evaluate variability in adaptation, 20 sedentary subjects and ten pairs of monozygotic twins were submitted to a 20-week endurance training program. Maximal oxygen uptake increased significantly in both groups: 11 mL O2/kg/min-1 or 30% in the sedentary group and 6 mL O2/kg/min-1 or 13% in the monozygotic twins. Statistically significant increases in left ventricular diameter, posterior wall and septal thicknesses, as well as left ventricular end-diastolic volume and left ventricular mass were observed in the sedentary subjects, but not in the monozygotic twins. We could demonstrate that after training, twin pairs differed more from each other than at the start. Concomitantly, within-pair resemblance was greater after training than before. Results indicate that cardiac dimensions are amenable to significant modifications under controlled endurance training conditions and furthermore that the extent and variability of the response of cardiac structures to training are perhaps genotype dependent.

Adult↗
PubMed1984

Vigorous physical training after aortic valve replacement: analysis of 10 patients.

Improved prosthetic aortic valves have reduced the incidence of complications to a point where it can be hypothesized that functional class I subjects after aortic valve replacement (AVR) should adapt to a vigorous training program without a significant increase of hemolytic activity or clinical signs of prosthesis malfunction. To test this hypothesis, 10 men (mean age 52 years) who had undergone AVR (7 Björk-Shiley and 3 Lillehei-Kaster) were submitted to an 8-week training program on ergometer, 3 times/week, from 60 to 80% of individual maximal heart rate. Ten other men who had undergone AVR but did not participate in the training program were control subjects. The exercise program produced significant improvements in posttraining maximum tolerated ergometer work load (210 kpm, p less than 0.001), in maximum total body oxygen consumption (5 ml/kg X min-1, p less than or equal to 0.01) and in double product at submaximal work load (-5,126, p less than or equal to 0.01). After training, hemoglobin decreased by about 1 g% (p less than or equal to 0.05) and hematocrit, reticulocyte counts and haptoglobin did not change significantly. Serum LDH and serum AST did not increase. Pre- and post-training echocardiograms did not show detectable alterations. Thus, patients with AVR who are in functional class I can adapt to a physical exercise program without significant adverse effects.

Aortic Valve↗
PubMed1984

Responses of maximal aerobic power and capacity to aerobic training.

The purpose of this experiment was to investigate the individual differences and the specificity in the response of maximal aerobic power (MAP) and capacity (MAC) to a 20-week aerobic training program. Twenty-four subjects (25 +/- 4 years), ascertained as sedentary, including 13 women and 11 men, participated in this study. MAP was determined with a progressive maximal ergocycle test, while MAC was computed as the total work output accomplished during a 90-min maximal ergocycle test. A modified bicycle ergometer allowed the exact measurement of the distance and the load for the computation of the work performed during MAC. The aerobic training program enhanced mean MAP/kg and MAC/kg by 33% and 51%, respectively. Although MAP/kg response to training was similar in both sexes, there was a sex difference in the response of MAC/kg, men improving 50% more than women. Individual differences in the response to the standardized training program were considerable with training gains ranging from 5% to 88% for MAP/kg and from 16% to 97% for MAC/kg. Correlations between training increments in MAP/kg with those in MAC/kg were rather low ranging from 0.28 to 0.44. These results indicate that there is a sex difference in the trainability of aerobic capacity, but not of maximal aerobic power, under the same 20-week aerobic training program. Moreover, large individual differences in the response to similar aerobic training are observed in sedentary persons, suggesting that certain genotypes are more sensitive to training than others. Finally, there is a high level of specificity in the response to training of the power and of the capacity of the aerobic energy metabolism.

Adult↗
PubMed1984

Sensitivity of maximal aerobic power to training is genotype-dependent.

Ten pairs of monozygotic twins of both sexes were submitted to a 20-wk endurance-training program, four and five times per week, 40 min per session, at an average of 80% of the maximal heart rate reserve. Testing and training were performed on cycle ergometers. Maximal aerobic power (MAP in ml O2 X min-1 X kg-1) and ventilatory aerobic (VAT) and anaerobic (VANT) thresholds (ml O2 X min-1 X kg-1) were measured before and after the training program, as well as during the 7th and 14th week to adjust training to changes in maximal heart rate. Considering the 20 individuals as a group, training significantly (P less than or equal to 0.01) increased MAP (from 44 +/- 6 to 50 +/- 6), VAT (25 +/- 3 to 30 +/- 4), and VANT (36 +/- 5 to 42 +/- 6). Thus, MAP improved by 12% of the pre-test value, while mean changes in VAT and VANT reached 20% and 17%, respectively. There were, however, considerable interindividual differences in training gains as exemplified by a range of about 0% to 41% for MAP. Differences in the MAP response to training were not distributed randomly among the twin pairs. Thus, intraclass correlations computed with the amount of improvement in MAP (ml O2 X min-1 X kg-1) reached 0.74 (P less than 0.01) indicating that members of the same twin-pair yielded approximately the same response to training. The same coefficient reached 0.43 and 0.24 for VAT and VANT, respectively (P greater than 0.05). These results suggest that there are considerable individual differences in the adaptive capacity to short-term endurance training. Moreover, sensitivity of maximal aerobic power to such training is largely genotype-dependent.

Adolescent↗
PubMed1980

The formation of phosphatidylethanolamine from diglyceride by extracts of Escherichia coli.

Extensively dialyzed cell-free homogenates or washed particulate fractions, of Escherichia coli in the presence of added CTP, Mg2+, serine, and rac-glycerol 3-phosphate, incorporated [32P]phosphatidic acid into phosphatidylglycerol and cardiolipin but not into phosphatidylethanolamine. [14C]Phosphatidic acid could be incorporated by these preparations into phosphatidylethanolamine in the absence of added CTP and Mg2+. CDP-diglyceride did not significantly affect the formation of [14C]phosphatidylethanolamine from [14C]phosphatidic acid. 14C-labeled diglyceride was also readily incorporated into phosphatidylethanolamine in the absence of added cofactors by both homogenate and particulate fraction. Serine stimulated the incorporation somewhat whereas CTP + Mg2+ diminished this conversion slightly because of concurrent [14C]phosphatidic acid and [14C]phosphatidylglycerol formation. CDP-diglyceride did not significantly affect the conversion of 14C-labeled diglyceride to phosphatidylethanolamine. Dialyzed 14C-labeled cytosol fractions of E. coli, obtained from cells grown in medium containing [14C]serine, transferred some of their label to phosphatidylethanolamine in the presence of fresh particulate fraction. This transfer was stimulated by added diglyceride. The results indicate that phosphatidylethanolamine can be synthesized from exogenous diglyceride by a pathway which does not require CDP-diglyceride as an intermediate but which likely makes use of an endogenous cofactor supplying phosphorylethanolamine and (or) phosphorylserine.

Carbon Radioisotopes↗
PubMed1980

The uptake and acylation of exogenous lysophosphatidylethanolamine by Escherichia coli cells.

Escherichia coli envelopes were fractionated to yield inner and outer membrane fractions. Both these fractions were found to convert [14C]lysophosphatidylethanolamine to its diacyl analogue. Intact Escherichia coli cells were capable of absorbing exogenous labelled lysophosphatidylethanolamine and converting it to phosphatidylethanolamine. When the 14C- and 32P-labelled lyso analogue was used, both the absorption process and the conversion to diacyl analogue proceeded without a significant change in isotope ratio either in the presence or in the absence of added inorganic phosphate. The absorption process was not markedly stimulated by Ca2+ in the medium; it proceeded to an amount representing 25--30% of the endogenous membrane lipid and was accompanied by some degradation to water-soluble products which accumulated in the cell mainly, but also in the incubation medium. The absorbed lipid was recovered in both the inner and outer membrane fractions of the cell envelope. The results indicate that Escherichia coli inner and outer membranes are capable of absorbing exogenous lysophosphoglyceride and converting it into structurally useful diacyl analogue.

Calcium↗