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Biomedical subjects

J Jobin

Publications and source records attributed to J Jobin.

At least 37 records · Page 2Linked to original sources
PubMed1998

Histochemical and morphological characteristics of the vastus lateralis muscle in patients with chronic obstructive pulmonary disease.

PURPOSE AND METHODS: In this study, we examined the fiber-type proportions, cross-sectional areas (CSA), and capillarization from needle biopsies of the vastus lateralis muscle in 20 patients with chronic obstructive pulmonary disease (COPD) (FEV1 = 37 +/- 11% predicted, peak VO2 = 13 +/- 4 mL.min-1.kg-1) and nine age-matched normal subjects (peak VO2 = 33 +/- 7 mL.min-1.kg-1). The effects of endurance training on these parameters were also evaluated in 11 of the 20 patients with COPD. RESULTS: The proportion of Type I fiber was smaller in COPD than normals (34 +/- 14% vs 58 +/- 16 in normals, P < 0.0005) with a corresponding increase in Type IIb fiber (P = 0.015). The CSA of Type I, IIa, and IIab fibers was also smaller in COPD. The capillary to fiber ratio tended to be reduced in patients, but this difference did not reach statistical significance (P = 0.15). The number of capillary contact for Type I, IIa, and IIab fibers was significantly reduced in COPD compared with normal subjects (P < 0.05). When corrected for the CSA, this parameter was similar for both groups. After training, peak VO2 increased by 11% (P < 0.05), the fiber-type proportion remained unchanged, and the CSA of Type I and IIa fibers increased by 31 and 21%, respectively (P < 0.05). Although the number of capillary contact for each fiber types increased with training, the capillary to fiber ratio and the number of capillary contact for the different fiber types relative to their CSA remain unchanged. CONCLUSIONS: We conclude that in COPD, 1) the vastus lateralis muscle is characterized by a marked decrease in Type I fiber proportion, an increase in Type IIb fiber proportion, a decrease in Type I, IIa, and IIab fiber CSA and by a relatively preserved capillarization; and 2) a 12-wk training program induces a significant increase in Type I and IIa CSA.

Aged↗
PubMed1998

Metabolic and hemodynamic responses of lower limb during exercise in patients with COPD.

Premature lactic acidosis during exercise in patients with chronic obstructive pulmonary disease (COPD) may play a role in exercise intolerance. In this study, we evaluated whether the early exercise-induced lactic acidosis in these individuals can be explained by changes in peripheral O2 delivery (O2). Measurements of leg blood flow by thermodilution and of arterial and femoral venous blood gases, pH, and lactate were obtained during a standard incremental exercise test to capacity in eight patients with severe COPD and in eight age-matched controls. No significant difference was found between the two groups in leg blood flow at rest or during exercise at the same power outputs. Blood lactate concentrations and lactate release from the lower limb were greater in COPD patients at all submaximal exercise levels (all P < 0.05). Leg D02 at a given power output was not significantly different between the two groups, and no significant correlation was found between this parameter and blood lactate concentrations. COPD patients had lower arterial and venous pH at submaximal exercise, and there was a significant positive correlation between venous pH at 40 W and the peak O2 uptake (r = 0.91, P < 0.0001). The correlation between venous pH and peak O2 uptake suggests that early muscle acidosis may be involved in early exercise termination in COPD patients. The early lactate release from the lower limb during exercise could not be accounted for by changes in peripheral O2. The present results point to skeletal muscle dysfunction as being responsible for the early onset of lactic acidosis in COPD.

Acidosis, Lactic↗
PubMed1998

Peripheral muscle weakness in patients with chronic obstructive pulmonary disease.

Peripheral muscle weakness is commonly found in patients with chronic obstructive pulmonary disease (COPD) and may play a role in reducing exercise capacity. The purposes of this study were to evaluate, in patients with COPD: (1) the relationship between muscle strength and cross-sectional area (CSA), (2) the distribution of peripheral muscle weakness, and (3) the relationship between muscle strength and the severity of lung disease. Thirty-four patients with COPD and 16 normal subjects of similar age and body mass index were evaluated. Compared with normal subjects, the strength of three muscle groups (p < 0.05) and the right thigh muscle CSA, evaluated by computed tomography (83.4 +/- 16.4 versus 109.6 +/- 15.6 cm2, p < 0.0001), were reduced in COPD. The quadriceps strength/thigh muscle CSA ratio was similar for the two groups. The reduction in quadriceps strength was proportionally greater than that of the shoulder girdle muscles (p < 0.05). Similar observations were made whether or not patients had been exposed to systemic corticosteroids in the 6-mo period preceding the study, although there was a tendency for the quadriceps strength/thigh muscle CSA ratio to be lower in patients who had received corticosteroids. In COPD, quadriceps strength and muscle CSA correlated positively with the FEV1 expressed in percentage of predicted value (r = 0.55 and r = 0. 66, respectively, p < 0.0005). In summary, the strength/muscle cross-sectional area ratio was not different between the two groups, suggesting that weakness in COPD is due to muscle atrophy. In COPD, the distribution of peripheral muscle weakness and the correlation between quadriceps strength and the degree of airflow obstruction suggests that chronic inactivity and muscle deconditioning are important factors in the loss in muscle mass and strength.

Aged↗
PubMed1997

Intensity of training and physiologic adaptation in patients with chronic obstructive pulmonary disease.

The applicability of high-intensity training and the possibility of inducing physiologic adaptation to training are still uncertain in patients with severe chronic obstructive pulmonary disease (COPD). The purposes of this study were to evaluate the proportion of patients with moderate to severe COPD in whom high-intensity exercise training (30-min exercise session at 80% of baseline maximal power output [Wmax]) is feasible, and the response to training in these patients. We also sought to evaluate the possible influence of disease severity on the training intensity achieved and on the development of physiologic adaptation following endurance training. Forty-two patients with COPD (age = 66 +/- 7 yr, FEV1 = 38 +/- 13% predicted, [mean +/- SD]) were evaluated at baseline and after a 12-wk endurance training program. Each evaluation included a stepwise exercise test on an ergocycle up to the individual maximal capacity during which minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), and arterial lactic acid concentrations were measured. The training consisted of 25 to 30-min exercise sessions on a calibrated ergocycle three times a week, with a target training intensity at 80% of Wmax. The training intensity was adjusted with the objective of reaching the target intensity, but also to ensure that the cycling exercise could be maintained for the specified duration. The training intensity sustained for the duration of each exercise session averaged 24.5 +/- 12.6, 51.7 +/- 17.4, 63.8 +/- 22.4, and 60.4 +/- 22.7% of Wmax at Weeks 2, 4, 10, and 12, respectively. High-intensity training was achieved in zero, three, five, and five patients at Weeks 2, 4, 10, and 12, respectively. A significant increase in VO2max and Wmax occurred with training (p < 0.0002). This improvement in exercise capacity was accompanied by a 6% and 17% reduction in VE and in arterial lactic acid concentration for a given work rate, respectively (p < 0.0001), suggesting that physiologic adaptation to training occurred. The intensity of training achieved, in % Wmax, was not influenced by the initial VO2max, age, or FEV1. The effects of training were compared in patients with an FEV1 > or = 40% or < 40% predicted. Percent changes in VO2max, Wmax, and VE, were significant and of similar magnitude for both groups, whereas the decrease in arterial lactic acid for a given work rate reached statistical significance only in those patients with an FEV1 > or = 40% predicted. We conclude that although most patients were unable to achieve high-intensity training as defined in this study, significant improvement in their exercise capacity was obtained and physiologic adaptation to endurance training occurred. The training intensity expressed as a percent of the individual maximum exercise capacity, and the relative effectiveness of training, were not influenced by the severity of airflow obstruction.

Adaptation, Physiological↗
PubMed1996

Oxidative capacity of the skeletal muscle and lactic acid kinetics during exercise in normal subjects and in patients with COPD.

Early lactic acidosis during exercise and abnormal skeletal muscle function have been reported in chronic obstructive pulmonary disease (COPD) but a possible relationship between these two abnormalities has not been evaluated. The purpose of this study was to compare and correlate the increase in arterial lactic acid (La) during exercise and the oxidative capacity of the skeletal muscle in nine COPD patients (age = 62 +/- 5 yr, mean +/- SD, FEV1 40 +/- 9% of predicted) and in nine normal subjects of similar age (54 +/- 3 yr). Following a transcutaneous biopsy of the vastus laterialis, each subject performed a stepwise exercise test on an ergocycle up to his or her maximal capacity during which 5-breath averages of oxygen consumption (Vo2), and serial La concentration measurements were obtained. From the muscle biopsy specimen, the activity of two oxidative enzymes, citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HADH), and of three glycolytic enzymes, lactate dehydrogenase, hexokinase, and phosphofructokinase were determined. The La/Vo2 relationship during exercise was fitted by an exponential function in the form La = a + bvo2, where be represents the shape of the relationship. The activity of the oxidative enzymes was significantly lower in COPD than in control subjects (22.8 +/- 3.3 versus 36.8 +/- 8.6 mumol/min/g muscle for CS, and 3.1 +/- 1.1 versus 5.5 +/- 1.4 mumol/min/g for HADH, p < 0.0005) and the increase in lactic acid was steeper in COPD (b = 4.3 +/- 2.0 versus 2.1 +/- 0.2 for normal subjects, p = 0.0005). A significant inverse relationship was found between CS, HADH, and b. No difference was found between the two groups for the glycolytic enzymes. We conclude that in COPD the increase in arterial La during exercise is excessive, the oxidative capacity of the skeletal muscle is reduced, and that these two results are interrelated.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1996

Skeletal muscle adaptation to endurance training in patients with chronic obstructive pulmonary disease.

The purpose of this study was to evaluate the physiologic responses to endurance training in patients with moderate to severe airflow obstruction by specifically looking at changes in skeletal muscle enzymatic activities. Eleven patients (age = 65 +/- 7 yr, mean +/- SD, FEV1 = 36 +/- 11% of predicted value, range = 24 to 54%) were evaluated before and after an endurance training program. Each evaluation included a percutaneous biopsy of the vastus lateralis and a stepwise exercise test on an ergocycle up to his/her maximal capacity. VE, VO2, VcO2, and serial arterial lactic acid concentration were measured during the exercise test. The activity of two oxidative enzymes, citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HADH), and of three glycolytic enzymes, lactate dehydrogenase, hexokinase, and phosphofructokinase was determined. The training consisted of 30-min exercise sessions on a calibrated ergocycle, 3 times a week for 12 wk. The aerobic capacity was severely reduced at baseline (VO2max = 54 +/- 12% of predicted) and increased by 14% after training (p < 0.05). For an identical exercise workload, there was a significant reduction in VE (34.5 +/- 10.0 versus 31.9 +/- 9.0 L/min, p < 0.05) and in arterial lactic acid concentration (3.4 +/- 1.3 versus 2.8 +/- 0.9 mmol/L, p < 0.01) after training. The lactate threshold also increased after training (p < 0.01) while the activity of the three glycolytic enzymes was similar at the two evaluations. In contrast, the activity of CS and HADH increased significantly after training (22.3 +/- 3.5 versus 25.8 +/- 3.8 mumol/min/g muscle for CS, p < 0.05, and 5.5 +/- 2.9 versus 7.7 +/- 2.5 mumol/min/g for HADH, p < 0.01). A significant inverse relationship was found between the percent changes in the activity of CS and HADH, and the percent changes in arterial lactic acid during exercise (p = 0.01). We conclude that endurance training can reduce exercise-induced lactic acidosis and improve skeletal muscle oxidative capacity in patients with moderate to severe chronic obstructive pulmonary disease (COPD).

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1996

Social support, social networks and coronary artery disease rehabilitation: a review.

OBJECTIVE: To provide information to the medical community about the importance of social support and networks through examination and definition of social support and network variables, and by reviewing the evidence found in the literature showing a relationship among social support, social networks, coronary artery disease (CAD) and rehabilitation. DATA SOURCES: Psyclit and Sociofile were searched for September 1979 through December 1994. STUDY SELECTION: All publications covering social support, social networks and rehabilitation from CAD as well as large mortality studies. Fifty-one articles were reviewed. DATA EXTRACTION: Original articles were summarized. DATA SYNTHESIS: Individuals who benefit from social support are less likely to become disease-stricken and live longer than those with less support. Social support and networks may have a substantial influence on the speed and quality of recovery following myocardial infarction (MI). CONCLUSIONS: A review of the literature indicates that social support plays an important role in recovery from and adaptation to chronic disease such as CAD and is of equal importance to the primary and secondary prevention of MI. Future research should pay special attention to what types of functional support are of most importance to recovery from MI and bypass surgery, thus allowing for the development of rehabilitation programs and interventions that will emphasize functions that are most needed. Interventions may involve the patient's natural support group to enhance the potential support providers' awareness of the patient's support needs. Social support may be especially important for maintaining compliance with rehabilitation programs for patients with CAD.

Adult↗
PubMed1995

Aortic flow velocity indices during upright exercise: reliability and relationship to cardiac output.

OBJECTIVE: To determine the intra- and interobserver reproducibility of Doppler-derived ascending aortic flow velocity measurements at rest and during upright exercise of increasing intensity; and to determine the relationship between Doppler-derived measurements and cardiac output obtained by the indirect Fick carbon dioxide rebreathing method in the same conditions. SUBJECTS: Twenty young healthy adults participated in the study; eight participated in the first part and 12 in the second. DESIGN: For the intra-observer study, subjects were submitted to three workloads (50, 100 and 150 W) of 5 mins duration on two occasions, seven days apart. The intra-observer reproducibility was determined by two technicians taking the Doppler measurements within 90 s during the steady state of each workload during the first session. The relationship between cardiac output and aortic flow velocities was studied by measuring cardiac output by carbon dioxide rebreathing and flow velocities by continuous wave Doppler ultrasound simultaneously at rest as well as during the last minute of the three workloads (50, 100 and 150 W) of 5 mins duration. RESULTS: The interobserver reproducibility was very good, with r values of 0.87 for peak velocity (PV) and 0.97 for peak acceleration (PA). The intra-observer reproducibility at the seventh day interval showed r values of 0.93 for PV and 0.96 for PA for one of the technicians. PV and PA of the ascending aortic flow correlated well with cardiac output (r = 0.85 and 0.82, respectively, P < 0.01). ANOVA showed that PV and PA increase proportionately with exercise intensity. CONCLUSION: PV and PA of ascending aortic flow are reproducible and reflect changes in left ventricular function during exercise.

Adolescent↗
PubMed1991

Prediction of intention to exercise of individuals who have suffered from coronary heart disease.

The aim of the study was to understand the intention to exercise of individuals who suffer from CHD. A group of 161 cardiac patients completed a questionnaire that investigated intentions, attitudes, subjective norms, perceived barriers, habits, perceived difficulties, and personal normative beliefs with respect to exercising, as well as perceived severity of and perceived vulnerability to re-infarction. Regression of intention yielded an R2 of .41 (p less than .0001), with perceived barriers, habits, and perceived difficulties as the significant predictors. MANOVA indicated that high and low intenders differed (p less than .01) according to their perception of three barriers: difficulties in time management, difficulties in psychological adaptation, and laziness. These results suggest that new guidelines should be adopted for the development of cardiac rehabilitation exercise programs.

Coronary Disease↗
PubMed1991

Physiological responses to maximal exercise on arm cranking and wheelchair ergometer with paraplegics.

This study describes the responses of 20 paraplegic athletes (mean age: 26.8 +/- 1.6 years) to a continuous incremental workload test until exhaustion on an arm cranking ergometer (ACE) and on a wheelchair ergometer (WCE). Both ergometers used the same electromagnetic braking device allowing a fair comparison between results. Tests were conducted at a 24 hour interval at the same time of the day. Oxygen uptake (VO2), heart rate (HR), workload (W), blood pressure (BP), Borg index, and mechanical efficiency (ME) were measured at every minute during the effort and the cool down periods of both tests. The purpose of this study was to analyse the different responses obtained on ACE and on WCE during maximal effort by paraplegics, and also to determine which ergometer permits the higher ME. Results indicate that paraplegics reached the same max HR on ACE and on WCE (97% of the predicted max HR). The lack of significant difference (p less than 0.05) between ACE and WCE in terms of maximal values of VO2, VE and HR suggests that the subjects reached their maximal capacity on each test regardless of the type of ergometer. Nevertheless, W max (in Watts) was 26% higher on ACE than on WCE. Maximal ME values were respectively 16% and 11.6% on ACE and WCE. Results suggest that ergometers and protocol used in this study are appropriate to measure physiological responses of paraplegic athletes during arm cranking and wheelchair exercise without excessive or early arm fatigue.

Adult↗
PubMed1991

Irreversible renal failure associated with triamterene.

A 66-year-old man was admitted with acute oliguric renal failure. The patient was known to have chronic heart failure (ejection fraction 13%) and his medication included furosemide, digoxin and triamterene. Physical examination was unremarkable, and blood pressure was 170/80 mm Hg. Serum creatinine was 1,173 mumol/l. Renal ultrasound, CT scan and angiogram were normal. Despite correction of potential reversible factors and discontinuation of triamterene, renal function did not improve. Renal biopsy showed tubular obstruction with deposition of birefringent crystals and interstitial lymphocytic infiltration; the crystals emitted a blue autofluorescence at 425 nm, typical of triamterene. Renal tissue contained large amounts of triamterene (6.44 mg/g kidney at the initial biopsy and 400 micrograms/g kidney 5 months later). Triamterene has been previously reported to cause acute reversible renal failure, but to our knowledge, this is the first case of irreversible renal failure due to intratubular obstruction by triamterene crystal deposition.

Acute Kidney Injury↗
PubMed1990

iPTH values during hemodialysis: role of ionized Ca, dialysis membranes and iPTH assays.

The evolution of serum iPTH concentration during hemodialysis was studied in eight patients who were dialyzed with cuprophane (Cu) and polyacrylonitrile membranes (PAN) during two four-hour sessions. Ca+(+) concentration in the dialysate was 1.37 mM/liter. iPTH was measured with an intact hormone immunoradiometric assay (I), with two late (L1, L2) and one mid (M) carboxylterminal immunoassays at the beginning and end of hemodialysis, from the arterial and venous sides of the extracorporeal unit. Results are means +/- SD. Serum Ca+(+) increased during dialysis with Cu (1.26 +/- 0.08 vs. 1.33 +/- 0.03 mmol/liter, P less than 0.05, without any change in the concentration of iPTH measured with L1, L2 or M, but with a 50% decrease in iPTH measured with I (21.8 +/- 19.2 vs. 10.3 +/- 9.0 pmol/liter, P less than 0.05). Serum Ca+(+) increased similarly with PAN (1.25 +/- 0.10 vs. 1.34 +/- 0.04 mmol/liter, P less than 0.01), but there was a greater than 50% decrease in iPTH concentration measurements for all four assays (I: 17.2 +/- 17 vs. 7.6 +/- 8.3 pmol/liter, P less than 0.05; L1: 92 +/- 75 vs. 36 +/- 32 pmol/liter, P less than 0.05; L2: 312 +/- 289 vs. 126 +/- 128 pmol/liter, P less than 0.01; M: 926 +/- 1074 vs. 373 +/- 422 pmol/liter, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗
PubMed1990

Optimism and health-relevant cognitions after a myocardial infarction.

The relationship between dispositional optimism (LOT) and health-relevant cognitions after a myocardial infarction was examined with 158 patients (mean age = 52.7 +/- 8.1 yr.). Patients above the median on optimism (i.e., optimists) scored significantly lower on perceived susceptibility, perceived severity, and experienced fear than did pessimists. However, no difference on perceived self-efficacy was reported between optimists and pessimists. It is concluded that these results provide further evidence for the LOT's construct validity.

Adaptation, Psychological↗
PubMed1988

Endurance vs. strength training: comparison of cardiac structures using normal predicted values.

There are still disagreements concerning the adaptation of cardiac structures in relation to different training stimuli. To eliminate some of the variance due to individual differences in body surface area, we utilized a new approach based on the calculation of the percentages of each individual's normal predicted values (%NPV). We studied 46 strength (S, bodybuilders) and 57 endurance (E, runners) athletes. Left ventricular (LV) mass was 143.8 +/- 21.9 %NPV (mean +/- SD) in E vs. 134.3 +/- 23.4 %NPV in S (P less than 0.05), and LV volume was 131.0 +/- 24.0 %NPV in E vs. 120.0 +/- 25.5 %NPV in S (P less than 0.05). Moreover, the LV wall thickness-to-radius ratio did not differ from normal values in either group. From these data we conclude that 1) cardiac modifications are greater in E than S, 2) the predominant stimulus is a volume overload type in both groups, and 3) concentric LV hypertrophy may not be as prevalent in S as previously suggested.

Adult↗
PubMed1988

Smoking, alcohol consumption, lipid and lipoprotein levels.

The lipid profiles of 1165 French Canadian men (aged 42 to 59 years) were studied and related to drinking and smoking habits. Alcohol consumption and smoking were closely related, smokers consuming twice as much alcohol as non-smokers. When relative body weight, total cholesterol, triglyceride and alcohol consumption were controlled in a covariate analysis, plasma levels of high density lipoprotein (HDL) cholesterol, HDL2 and HDL3 differed significantly between smokers, ex-smokers and nonsmokers. Ex-smokers had higher levels of HDL cholesterol than nonsmokers who had higher levels than smokers. The higher levels of HDL in ex-smokers could be explained by the confounding effects of alcohol intake. Alcohol users had significantly higher levels of HDL cholesterol, HDL2 and HDL3 than nondrinkers. Men who drank the equivalent of more than 3 ounces of absolute alcohol per week had significantly higher levels of HDL cholesterol and HDL3 than those who drank less than 3 ounces or did not drink at all. HDL2 levels were only significantly different between nondrinkers and those who consumed more than 3 ounces per week. These results show that smoking and alcohol have strong but opposing effects on HDL and its subfractions in middle-aged French Canadian men.

Adult↗
PubMed1987

The impact of physical fitness and health-age appraisal upon exercise intentions and behavior.

This study investigated the relative and combined effectiveness of the Canadian Home Fitness Test (CHFT) and Health Hazard Appraisal (HHA) to modify (1) intention to exercise with and without knowledge of the results and (2) intention and behavior to exercise over 3 months. The 200 subjects were randomly attributed to groups, either (1) physical-fitness evaluation (PF), (2) appraised health age (HA), (3) physical-fitness evaluation and health-hazard appraisal (PF-HA), or (4) control (C). The immediate impact on the intention to exercise of passing one and/or the other tests, without knowledge of the results, was not significant. With knowledge of the results, the intentions of the PF and PF-HA groups differed from those of the C group. This effect disappeared after 3 months. There was no significant impact on exercise behavior over 3 months. The results indicated a short-term motivational effect from being informed of CHFT results. Maintaining this effect might require intervention on a long-term basis.

Adult↗
PubMed1985

Lipid profile of a French-Canadian population: 1. Association of plasma lipid and lipoprotein levels with age, relative body weight and education.

Plasma lipid and lipoprotein levels were determined in a randomly selected population of 1169 French-Canadian men in the Quebec City area. The mean levels of total plasma cholesterol and triglycerides were 224.0 and 166.5 mg/dL respectively. The mean level of low-density lipoprotein cholesterol was higher and the mean level of high-density lipoprotein (HDL) cholesterol lower than those reported in a recent study in English-Canadian men. The mean HDL2 and HDL3 levels were lower than those reported in American men. Stratification of plasma triglyceride levels for all age groups showed that mean HDL2 levels decreased rapidly with moderate rises in triglyceride levels. Less than 9% of the variation in lipid or lipoprotein levels was related to age or relative body weight. Education had no significant effect on the levels.

Adult↗