The normal arterial patterns in the left ventricle wall of 100 rabbit hearts were studied by means of postmortem coronary angiography, the clearing method and histological sections, and in comparison with that of the human heart.The intramural arterial patterns in the left ventricle of rabbit heart are similar to human heart in many ways. "Branching" type arteries (Class A vessels) supply the whole myocardium, including the subendocardial zone, while "straight" type arteries(Class B vessels)mainly supply the papillary muscle and trabeculae carneae where they form the subendocardial plexus. The arterial type in papillary muscles may be classified into segmental pattern, axial pattern and mixed pattern. The arterial distribution in the interventricular septum is without rule. The capillaries in all areas run parallel with the myocardial fibres and show cross connexions somewhere.

0.05). The ITA contains relatively higher content of elastin as compared with the others (P

Five resin casts of the coronary arteries and the hislological sections of three hesrts with the arteries injected Chinese ink were prepared in human adult autopsy subjec s . 3187 branches of the coronary arterial trees were counted and measured . By Strahler's system the branch pattern of the coronary arterial tree was described . According to the analysis of the geometrical morphology data, the relationships between the diameter , the length and the number of branches in each order and the branch order show the exponential function respectively , which have high correlation significance (p

0.05). ITA contains elastin a relatively higher than the other two (P

For the 1st and 2nd pts.see ibid vol.11,no.4t p.241 & p.251 (1989).The anterior interventricular branch and the circumflex branch of the left coronary artery and the right coronary artery were excised from 7 autopsy adult subjects without heart diseases.A biaxial loading test lor the vascular specimens was completed,which was simultaneously finished in the internal thoracic artery (ITA) and the great saphenous vein (GSV) of the same subjects in order to compare with the coronary arteries.Elastic moduli of the vessels increased with increasing pressure in the vessels.As compared with GSV the mechanical properties of ITA ap-proach the coronary arteries.It is assumed that the coronary artery bypass grafting choose ITA before GSV in view of the mechanical properties of the vascular walls.A ratio of collagen per elastin may be used as an index of the arterial elasticity.It is discussed that the biomechanical properties of the arteries may influence the pathogenesis of the arteriosclerosis.

For the first pt.see ibid vol.11 no.4,p.241 (1989).The anterior interven-tricular branch aad the circumflex branch of the left coronary artery,and the right coronary were excised from 7 autopsy adult subjects without heart diseases.A biaxial loading test for the vascular specimens was completed,which was simultaneously finished in the internal thoracic artery(ITA) and the great saphenous vein (GSV) of the same subjects in order to compare with the coronary arteries.Stress-strain relationships of the vessels were expressed by the exponential strain energy function.The meaning of the two-dimensional material constants for the vessels are discussed.

Intramural vescular changes in the healing process after myocardial infarction were studied by the methods of histological section after ligating the left coronary artery of 119 rats. The intramural vascular patterns in the left ventricular free wall of the rat heart are similar to those of the human and the rabbit, but the patterns in the interventricular septum of the rat heart are only similar to those of the rabbit. The left ventricutar free wall contains 3,903?48 capillaries per mm~2 on the average. The capillaries in all areas run parallel with the myocardial fibres. After figuring the left coronary artery of the rat heart,the intramural vascular changes may be divided into three stages, i.e.avascularity, hypervascularity and hypovascularity, which coincide with the healing process of myocardial infarction. It is suggested that the coronary collateral circulation begins within the first two days, and increases gradually during 3 to 7 days after myocardial infarction. The evolutionary process of blood vessels in experimental myocardial infarction of rats is more rapid than that in the human and in the rabbit, but the process itself is similar to each other.

The normal arterial patterns in the left ventricle wall of 100 rabbithearts were studied by the methods of postmortem coronary angiogram, theclearing method and histological section, compared with that of the humanheart. The intramural arterial patterns in the left ventricle of the rabbitheart are similar to those of the human heart. "Branching" type arteries(Class A vessels) supply the whole of myocardium, including the subendoca-rdial zone, while "straight" type arteries(Class B vessels)mainly supply thepapillary muscle and trabeculae carneae where they form the subendocardialplexus. The arterial type in papillary muscles may be classified intosegmental pattern, axial pattern and mixed pattern. The arterial distributionof the left ventricular side in the interventricular septum is ruleless. Thecappillaries in all areas run parallel with the myocardial fibres and showthe crosscorexions somewhere.

Objective The effect of vascular smooth muscle cells (VSMCs) on the PDFG\|B mRNA expression of Co\|cultured endothelial cells (ECs) under shear stress had been studied in order to provide some experimental data for preventing the development of restenosis resulted from VSMCs proliferation in the vascular graft. Methods The level of PDGF\|B mRNA of ECs cultured alone and Co\|cultured with VSMCs exposed to shear stress were investigated by the methods of in situ hybridization and image analysis. Both controls of ECs cultured alone and Co\|cultured with VSMCs were maintained under static conditions. Results In static condition, the content of PDGF\|B mRNA expression of Co\|cultured ECs was lowered in comparison with ECs alone\|cultured. Under shear stress, PDGF\|B mRNA expression of Co\|cultured ECs was increased in transient manner at 1hour after the onset of shear stress and then returned to the level lower than the static level of Co\|cultured ECs at 6hours after being exposed to shear stress. The transient increasing time of PDGF\|B mRNA expression of Co\|cultured ECs reached a maximum earlier than that of ECs cultured alone.Conclusion Under shear stress, PDGF\|B mRNA expression of ECs Co\|cultured with VSMCs is lowered, which may be favor of inhibiting VSMCs proliferation.

Objective To investigate effects of low shear stress on atherosclerosis,the development of atherosclerosis and expression of ?actin and cMyc proteins were studied in VSMC of common carotid artery under low shear stress. Methods We established the atherosclerotic model of left common carotid artery that presented low shear stress by the operation of ligating the left external carotid artery in rabbits.The histomorphology of the carotid arteries was examined by light microscopy.The expression of ?actin and cMyc was studied by immunohistochemistry. Results The typical atherosclerosis was observed and the atherosclerotic lesion was obviously accelerated under low shear stress.The expression of ?actin was downregulated and the phenotype of VSMC converted from contractile phenotype into synthetic phenotype,and expression of cMyc increased in VSMC of the artery under low shear stress.Conclusion This new model of atherosclerosis under low shear stress was successfully established,which provides a new tool for studying the effects of low shear stress on atherosclerosis.The results show that the atherosclerotic lesion is obviously accelerated and VSMC tends to proliferate in response to low shear stress.