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Biomedical subjects

G Tremblay

Publications and source records attributed to G Tremblay.

At least 73 records · Page 4Linked to original sources
PubMed1982

Left ventricular dimensions following training in young and middle-aged men.

To document the effects of endurance training upon left ventricular dimensions, an echocardiographic examination was performed on 11 young (19 +/- 1 years) and 13 middle-aged (40 +/- 3 years) subjects before and after a 20-week endurance training program. The maximal working capacity was increased by 28% and 27% in young and in middle-aged subjects, respectively. Following training, the left ventricular posterior wall and septal thickness in diastole were unchanged both in young (10.1 +/- 0.2 mm and 9.0 +/- 0.2 mm, pre-; 10.1 +/- 0.2 mm and 9.3 +/- 0.3 mm, post-) and in middle-aged subjects (10.0 +/- 0.3 mm and 10.2 +/- 0.3 mm, pre-; 9.7 +/- 0.2 mm and 10.1 +/- 0.2 mm, post-); the left ventricular end-diastolic internal diameter was unchanged in middle-aged subjects (47.8 +/- 0.9 mm, pre-; 48.1 +/- 1.0 mm, post-) but was significantly increased in young subjects (47.8 +/- 1.0 mm, pre-; 49.9 +/- 1.0 mm, post-) (P less than 0.05). These data could suggest that the left ventricular adaptation to training decreases with age. However, the decrease in resting heart rate observed in young subjects (68 +/- 3 to 60 +/- 2 beats X min-1) (P less than 0.05) but not in middle-aged subjects (63 +/- 3 and 65 +/- 3 beats X min-1) could also increase diastolic filling time and explain the small left ventricular end-diastolic enlargement found in the young subjects.

Adult↗
PubMed1982

Relationship between stroke volume and pneumocardiogram.

The intratracheal pressure oscillations produced by the heartbeat, called the pneumocardiogram, were recorded in 15 dogs. It was found that a linear relationship existed between the amplitude of the major negative deflection of the pneumocardiogram and the cardiac stroke volume, the latter determined either by indicator dilution (avg r = 0.94) or by use of an electromagnetic flow probe (avg r = 0.95). This relationship existed in animals with both an open and a closed chest. The vector of left ventricular wall motion directed toward the lungs, determined by high-speed cineradiography of the motion of a tantalum marker inserted in the wall of the left ventricle, looked very similar to the pneumocardiogram. This study showed that the pneumocardiogram can be used as a noninvasive technique to measure changes in stroke volume and is caused primarily by the motion of the cardiac walls.

Animals↗
PubMed1981

Autoradiographic demonstration of uptake and retention of 3H-estradiol after in vitro incubation.

An in vitro incubation method is described for the demonstration of 3H-estradiol in sections of mouse uterus by thaw-mount autoradiography. The method involves the incubation of tissue sections in 5 nM 3H-estradiol with a subsequent 2 hr chase in medium containing 3.5 g% bovine serum albumin. The distribution of the silver grains observed compares favorably to that seen by others with dry-mount autoradiography after in vivo injection. The labeling is inhibited by excess estradiol or diethylstilbesterol, but not by progesterone or hydrocortisone. Its subcellular distribution appears predominantly nuclear in presumptive target cells. Some regional variability in degree of labeling is present throughout the sections, but is far less marked within a given area. Because the observed labeling has been retained during a 2 hr chase and can be inhibited, it is likely to represent physiologically significant uptake and retention of 3H-estradiol in target cells. Preliminary results with human mammary carcinoma suggest this method may be applicable to the investigation of estrogen target cells in human tissue.

Animals↗
PubMed1981

[Use of echocardiography in the diagnosis of pulmonary hypertension].

There are few data regarding the sensitivity and specificity of the pulmonic valve echogram in the detection of pulmonary hypertension (PHT). In the present study, simultaneous pulmonic echograms were evaluated in 40 patients with normal pulmonary artery pressure and 24 with PHT (mean pressure greater than 20 mmHg). The A wave depth (Amax) was 4.0 plus or minus 1 mm (2-6 mm) in normals but was (1.05 plus or minus 0.2 mm) (p less than 0,001) in PHT and was absent in 5 of 24 PHT patients with a mean pulmonary artery pressure (MPAP) greater than or equal to 35 mm. The ef slope in normals was 22 plus or minus 1.8 mm and 7.1 plus or minus 2 mm (p less than 0.01) in patients with PHT. A negative slope was observed in 4 patients with severe PHT (MPAP) greater than or equal to 40 mm, but never in normals or in patients with mild PHT. The opening velocity (OV) was significantly higher in PHT patients 363.2 plus or minus 19.3 verus 293 plus or minus 7.3 mm/sec (p less than 0.01). Normal values were found in patients with moderate to severe PHT but an OV greater than or equal to 450 mm/sec was not encountered within the normal group. A mid-systolic notch was observed in 10 patients with PHT of which 9 with a MPAP greater than or equal to 35 mmHg. The maximum systolic excursion of the pulmonary valve in both groups did not differ significantly (13.3 plus or minus 0.5 vs 12.8 plus or minus 0.3). Even less specific, the systolic intervals (PEP/ET), were raised greater than or equal to 0.30 in 12 out of 15 with PHT. In conclusion, the reduction or disappearance of Amax with sinus rhythm, a flattening or negativation of ef slope and the presence of a mid-systolic notch were found to be the 3 most reliable criteria to detect and quantify PHT.

Adolescent↗
PubMed1980

Electro- and echocardiographic study of the left ventricle in man after training.

Fourteen sedentary middle-aged men underwent a chest X-ray, a 12 lead ECG, a VCG, and an echocardiographic examination prior to and following 5 months of training a moderately severe intensity, on a cycle ergometer. No modification in the X-ray cardiac profile was observed following training. Some electrocardiographic (R wave amplitude in V5 and V6 and Sokolow index: SV1 + RV5 or V6) and vectorcardiographic (maximal QRS vector amplitude, maximal spatial QRS vector, and R wave amplitude) indices of left ventricular hypertrophy were slightly but significantly increased following training. The echocardiographic measurements in diastole (septal and posterior wall thickness, left ventricular internal diameter, and left ventricular mass) were unchanged after training. Results suggest that electrical changes may not provide adequate indications of left ventricular morphological modifications. The lack of echocardiographic evidences of left ventricular hypertrophy suggest that: (1) training does not necessarily induce left ventricular hypertrophy; (2) the large heart sometimes observed in athletes may be the result of a genetic factor or of a prolonged and very intensive training pursued since a very young age, over a number of years; and (3) left ventricular enlargement probably plays a minor role in the increase in aerobic capacity following training.

Echocardiography↗
PubMed1979

[Early and late outcome after aortocoronary bypass: experience in 500 cases].

Between 1971 and 1976, 500 patients underwent aortocoronary bypass surgery. There were 15 operative deaths (3%) and the total frequency of perioperative infarction was 7%. The operative mortality was 7.4% in unstable angina, as compared with 1.1% in stable angina (P less than 0.01). The proportion of grafts patent at 2 weeks was 92% and at 18 months 87.6%. Postoperative follow-up was complete for 99% of the patients. There were 15 late deaths (3%) and the rates of survival at 2 and 4 years were 94.4% and 92.1% respectively. The actuarial curve of survival after surgery was not significantly different from that of the general population. After a mean follow-up of 27 months 73% of the patients were completely free of angina and 19% were markedly improved. The rate of recurrence of angina averaged 10% per year and the annual infarction rate was 0.7%. Fourteen patients (3%) underwent reoperation during the follow-up period. Thus, coronary revascularization surgery offers effective and sustained relief of incapacitating angina and might also improve survival if the operative mortality is low.

Adult↗
PubMed1979

Myofibroblasts in the stroma of invasive and metastatic carcinoma: a possible host response to neoplasia.

After observing the presence of numerous stromal myofibroblasts in scirrhous mammary carcinomas, a series of invasive and metastatic carcinomas from diverse sites was examined by electron microscopy to determine whether myofibroblasts might also be present in their stroma. Myofibroblasts were identified in each instance and were most abundant in neoplasms which were hard, sclerotic, and retracted. This finding suggests that myofibroblasts represent a component of the stromal reaction to many carcinomas and contribute to the desmoplasia and retraction which characterize many of these neoplasms. The host commands several responses to neoplasia. As a result of the expression of tumor-associated antigens, the immune system contributes lymphocytes, macrophages, and antibodies, a reflection of immunologic surveillance against neoplasia. In contrast to experimental systems tumor neoantigens are poorly expressed or even lacking in many human neoplasms; thus, the immune system may be weakly stimulated or not activated at all. Tumor neovascularization induced by a tumor-angiogenesis factor represents a second host response, possibly deleterious, for it may facilitate tumor dissemination. The stromal myofibroblast reaction to many invasive and metastatic carcinomas may constitute a third, albeit more primitive response. The density of collagen produced and contractile state of such tissue may signify an attempt by the host stroma to contain the neoplasm and impede vascular invasion. If so, myofibroblast induction may complement immune surveillance or constitute a separate mechanism of response to invasive neoplasia in man.

Carcinoma↗
PubMed1978

Dissociation between clinical and exercise responsiveness to beta-blockade in angina.

Twenty outpatients with mild angina were prescribed placebo tablets b.i.d. for 7 weeks followed by acebutolol, a cardioselective beta-blocker, 200 mg b.i.d. for 21 weeks under single-blind conditions. One graded multistage treadmill test was carried out after each treatment period and an angina diary was filled daily for the 6 months of the trial. Attack frequency declined by 71% from 2.59 per week on placebo to 0.76 per week on acebutolol (p less than 0.05). Exercise duration on the treadmill increased by 56%, from 5.95 minutes on placebo to 9.32 minutes on acebutolol (p less than 0.001). A satisfactory clinical response (50% or greater decline in attack frequency per week) occurred in 15 out of 19 patients (79%; a 100% or greater increase in exercise duration on the treadmill was observed in 10 out of 19 cases (53%). Exercise responsiveness was well predicted by exercise duration on placebo (r = 0.91, p less than 0.0005), patients with the least initial tolerance being the most improved. Clinical responsiveness was not well predicted by initial exercise tolerance (r = 0.38, N;S.) or by the improvement in exercise tolerance (r = 0.33, N.S.). It is concluded that acebutolol substantially reduces anginal attack frequency even in patients in whom exercise tolerance is not significantly improved, at the dose of 400 mg/day.

Acebutolol↗
PubMed1978

A new method for the precise and complete correction of distortion on cineangiographic image: its effect on left ventricular measurements.

Some of the problems associated with the precise evaluation of left ventricular volumes from angiographic images are due to the magnification and distortion of the pictures obtained from X-ray equipment. Magnification errors can be evaluated easily but the distortion (due to pincushion effect) are more difficult to measure. A mathematical method is proposed for a complete point-by-point correction of errors due to magnification and X-ray distortion. This method is applicable to most currently used angiographic equipment. Since more and more angiographic images are processed with local or remote digital computers, the applicability of the proposed technique becomes realistic. Results from this study show that a 5-30% overestimation of usual geometric ventricular parameters is encountered if no correction is made for distortion. End-diastolic measurements are more affected than end-systolic ones because of the greater degree of spherical distortion at the periphery of the picture area.

Cardiac Volume↗
PubMed1977

Elastosis in benign sclerosing ductal proliferation of the female breast.

Elastosis, an abundance of elastic tissue, is commonly present in breast carcinoma. However, its diagnostic significance remaines an unsettled issue. This study documents 17 cases of elastosis occurring in a distinctive benign sclerosing ductal lesion of the female breast (Fenoglio and Lattes: Cancer 33: 691-700, 1974). Elastosis was characterized by staining reactions and, in several instances, by elastase digestion and electron microscopy. Yellow streaks and flecks may be apparent grossly and probably reflect the increased elastic tissue. Histologically, the lesion is generally stellate with central sclerosis and marked peripheral intraductal and ductular hyperplasia which is often papillary. Elastosis, which may be marked, is a constant finding and is predominantly periductal in location. It is emphasized that the gross and histologic features of the lesion may mimic carcinoma and that elastosis may be found in benign ductal lesions of the breast.

Adult↗