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Biomedical subjects

C Beghi

Publications and source records attributed to C Beghi.

44 records · Page 3Linked to original sources
PubMed1984

Morphometry of right and left ventricular myocardium after strenuous exercise in preconditioned rats.

Young male rats were exposed to a biphasic training program in which a 7-week preconditioning period of moderate treadmill exercise was followed by 8 weeks of strenuous endurance running. In comparison with sedentary control animals, the trained rats at 20 weeks of age had developed myocardial hypertrophy of the right ventricle (20%) and interventricular septum (23%), but there was no difference in the weight of the left ventricular free wall. Myocyte hypertrophy (26%) in the right ventricle was achieved through an increase in mean cell length (24%) and the addition of new sarcomere units in series. Exercise induced no acceleration of capillary growth in either ventricle, leading to significant decreases in the capillary luminal volume density (-21%) and surface density (-16%) in the right ventricle. Such alterations in the structural properties of the microvasculature implicated in oxygen availability and diffusion suggest that vigorous exercise, even after a preconditioning period, may still be detrimental to the myocardium. The techniques of myocardial morphometry were examined with respect to potential errors associated with oblique tissue sections and the use of light versus electron microscopy for cell counting. It was shown that the practical effects of obliquity are negligible and that electron microscopic resolution is essential.

Animals↗
PubMed1983

Stress tests.

Explore the source record for details and available documents.

Coronary Disease↗
PubMed1983

Morphometry of exercise-induced right ventricular hypertrophy in the rat.

In our morphometric study of the effects of exercise on the heart, male Wistar-Kyoto rats at 5 weeks of age were subjected daily to a moderate treadmill running program that lasted for 7 weeks. The heart responded to physical conditioning by different magnitudes of tissue growth of the right (22%) and left (7%) ventricular myocardium, the latter change not statistically significant. The increase in right ventricular volume was associated with a 25% enlargement of ventricular area, a 26% average lengthening of the myocytes, and no change in sarcomere length and in ventricular midwall thickness. Exercise produced significant alterations in the quantitative parameters of the microvasculature of the right ventricle, but no appreciable changes in the left ventricle. Right ventricular hypertrophy was characterized by an absolute 44% growth of the endothelial luminal surface brought about through a 16% increase in capillary numerical density, and a 41% augmentation of the total length of the capillary network. Maximum diffusion distance from the capillary wall to the mitochondria of myocytes decreased 10% as a result of capillary proliferation and the lack of lateral expansion of myocyte cross-sectional area. Evaluation of the subcellular constituents of myocytes showed no change in the mitochondria:myofibrils volume ratio, indicating a growth of these components proportional to each other and to the growth of the myocyte population as a whole. It was concluded that, as a result of running exercise, right ventricular growth is analogous to eccentric hypertrophy in which the structural adaptations of the capillary bed can be expected to improve the diffusion and transport of oxygen within the tissue.

Animals↗
PubMed1982

Morphometry of right ventricular hypertrophy induced by strenuous exercise in rat.

Effects on the myocardium, particularly those structural properties of the capillary network relevant to tissue oxygenation, were studied morphometrically in rats subjected to a severe running program. Physical conditioning produced a 31% increase in right ventricular weight and only a 12% increase in the weight of the left ventricle. Quantitative analysis of right ventricular myocardium demonstrated relative decreases in capillary luminal volume density (-27%) and capillary luminal surface density (-20%) and an increase in the average maximum distance from the capillary wall to the mitochondria of myocytes (14%). In contrast, the contractile mass expanded in proportion to the growth of the ventricle through augmentation of the cross-sectional area (17%) and length (19%) of the average myocyte. Evaluation of the subcellular constituents of myocytes showed no change in the mitochondria-to-myofibril volume ratio. In conclusion, the capillary bed controlling oxygen availability, diffusion, and transport suggests that excessive physical activity may be detrimental to the myocardium.

Animals↗
PubMedDate not supplied

Carotid endarterectomy under hypothermic extracorporeal circulation: a method of brain protection for special patients.

This study was undertaken to evaluate the efficacy of hypothermic extracorporeal circulation for cerebral protection in 17 patients having simultaneous carotid endarterectomy and cardiac operations. The cardiopulmonary by-pass (CPB) was conducted using total hemodilution. The body temperature was cooled to 25 degrees C and the heart was arrested with cardioplegic solution. The carotid endarterectomy was performed first followed by the cardiac operation. No neurological or cardiac complications occurred. These results support the reliability of hypothermic cardiopulmonary bypass as a method of providing cerebral protection during simultaneous cardiac and carotid surgical procedures.

Aged↗
PubMedDate not supplied

Right atrial hemangioma.

A case of right atrial hemangioma as a rare tumor of the heart is reported. Because of its single, pedunculated mass, surgical excision of the tumor resulted in the complete treatment. Histologically, it was classified as arteriolar type. The importance of recent non-invasive techniques to diagnose these tumors during life is emphasized.

Echocardiography↗
PubMedDate not supplied

Asymptomatic patient reoperated on for severe proximal stenosis of circular sequential vein graft.

The case is described of a fifty year old man who underwent coronary bypass surgery using the circular sequential vein graft technique. At follow-up study (6 months after operation), despite his asymptomatic status, the effort test revealed antero-lateral myocardial ischemia. A coronary angiography showed a 90% proximal stenosis of the graft at 1.5 cm from the aortic anastomosis. The patient was reoperated on and the circular graft was reconstructed. Despite the severe stenosis this technique of myocardial revascularization has developed intercoronary anastomoses, improving the cardiac contractility and avoiding further clinical complications.

Coronary Artery Bypass↗