The study of mechanical properties on heart valves can provide an important theoretical basis for doctors to repair heart valves and prosthetic valve materials research. In this paper, we present the current status of the mechanical property study methods of heart valve, expound the methods and special requirements about uniaxial tensile test and biaxial tensile test of the heart valve, and further discuss several establishment methods of heart valve constitutive models. We also discuss the development trend of heart valve mechanics.
Heart Valve Prosthesis ; Heart Valves ; physiology ; Humans ; Prostheses and Implants

Objective: To investigate constitutional and phys ical stamina status in soldiers with different adaption periods in Tibetan areas . Methods: Two hundred and eithty-two male soldiers from a barr acks at an elevation of 3 600 m were divided into 2 groups: the veteran group ( n=143) in Tibet for 1.45±0.22 year, and the recruit group (n=139) in Ti bet for 0.33±0.00 years. The test items included body weight, cirumference, st a nding long jump, chin-up, 100 m dash and 3 000 m jogging, all were evaluated ac cording to the national military standard, which were Comprehensive Evaluation o f Health in Troops, and Examination and Evaluation of the Physical Stamina of So ldiers. Results: The physical stamina indexes of both the vetera ns and the recruits were up to the national military norm on the whole, ranking as moderate. The veteran group showed no significant difference in standing long jump and 100 m dash,（P<0.05), but obvious lower level in chin-up and 3 00 0 m jogging（P<0.01）, compared with the national military norm. The recr ui t group showed significant lower level in chin-up, 100 m dash, 3 000 m jogging as compared with the national military norm（P<0.01）, and also significant lower level in chin-up and 3 000 m jogging （P<0.05 or P<0.01) as compa red with the veteran group. Conclusion: The physical stamina of both the veterans and the recruits meet the basic national military requirements , ranking as moderate. The soldiers who have been in service for over 1 year hav e better explosive force, but they need more tolerance and aerobic exercises. Th e newly recruited need more exercise to raise tolerance to the hypoxic environme nt in plateau areas so as to shorten the adaption time to high altitude.

ObjectiveTo observe the efficacy and side effects of paroxetine and amitriptyline in the treatment of post-stroke depression (PSD).Methods82 PSD patients were randomly divided into the paroxetine group (n=42) and amitriptyline group (n=40). Before the treatment and at the ends of 2nd, 4th and 8th week after the treatment, all patients in two groups were assessed with Hamilton Depression Scale (HAMD) and TESS.ResultsAfter treatment, HAMD scores of patients of two groups were decreased significantly (P<0.01), but no difference was found between two groups. The side effects of the paroxetine group were obviously fewer and milder than that of amitriptyline group (P<0.01).ConclusionParoxetine is an effective and safe drug in the treatment of PSD.

Hemodynamic situation is an important factor of recurrence of postoperative carotid artery aneurysm. In order to investigate the hemodynamic factors of postoperative carotid artery aneurysm affect carotid artery aneurysm recurrence, we established a 3D finite element carotid artery aneurysm for the preoperative and postoperative periods using the three-dimensional reconstruction techniques. And then we measured the hemodynamic factors of carotid artery aneurysm of preoperative and postoperative by the finite element method. The carotid artery aneurysm model has an accurate and realistic shape; the pressure of the recurrence of aneurysm was reduced significantly after surgery,wall shear stress increased significantly at residual neck, and blood flow velocity increased significantly, which will increase the risk of recurrence. The hemodynamic analysis provides a reference for development of aneurysm clinical treatment programs and prevention of recurrence.
Aneurysm ; pathology ; surgery ; Blood Flow Velocity ; Carotid Arteries ; pathology ; surgery ; Computer Simulation ; Hemodynamics ; Humans ; Stress, Mechanical

BACKGROUND: Vascular smooth muscle cell(VSMC) is one of the major cell components of vascular wall and its pathologic effects in atherosclerosis has been verified and recognized. How to inhibit VSMC proliferation and migration becomes one of the hotspots in the researches regarding the prevention of coronary heart disease(CHD).OBJECTIVE: To observe the impacts of diethyl-2, 6-diethyl-4-furny-1,4-dihydropyridine-3, 5-dicarboxylate(EFDP) on angiotensin Ⅱ (Ang Ⅱ)-induced VSMC proliferation.DESIGN: A randomized controlled study based on VSMC of rabbit' s thoracic aorta cultured in vitro.SETTING: Department of cardiology in a military medical university of Chinese PLA.MATERIALS: The study was conducted in the Laboratory of Cardiology of Xijing Hospital of the Fourth Military Medical University of Chinese PLA between August 2003 and June 2004. Five New Zealand rabbits were selected for the harvest of VSMC. Animal cells were randomly divided into control group, Ang Ⅱ group and Ang Ⅱ + EFDP group(EFDP group).METHODS: New Zealand rabbits were fed by high-fat food. Thoracic aorta was harvested for the separation and culture of VSMC after the injury in thoracic aorta intima by sacculus. The experiment introduced the cultured rabbit VSMC to observe the impacts of EFDP on VSMC DNA synthesis and its time effect during VSMC proliferation promoted by Ang Ⅱ by 3H-TdR method.MAIN OUTCOME MEASURES: 3H-TdR intensity of radio activity in cells of each group to display the DNA synthesis during VSMC proliferation process.RESULTS: Ang Ⅱ could promote the synthesis of rabbit VSMC DNA, which hit its peak at the 36th hour compared with that of control group(358. 00± 49.01 vs 272.42 ± 54.96, P ＜ 0. 01 ) . EFDP had significant inhibitive effects on Ang Ⅱ-induced VSMC proliferation, which also displayed a significant dose-dependent relationship, i.e. with the elevation of EFDP concentration, its inhibitive rate on VSMC proliferation also gradually increased. At the 36th hour, 78.40 μ mol/L of EFDP had more significant effect than that of 0. 08 μmol/L of EFDP(281.50 ± 15.28 vs 349. 25 ±32.10, P＜ 0. 05).CONCLUSION: EFDP can significantly inhibit Ang Ⅱ-induced rabbit VSMC proliferation with certain dose-effect dependency and time responses,which provides a theoretical gist for the primary rehabilitative prevention of atherosclerosis.

AIM: To investigate the effects of calcitonin gene-related peptide (CGRP) on cultured anoxic-reoxygenation human umbilical vein endothelial cells. METHODS:In the present experiment, an anoxic-reoxygenation model was established by using cultured human umbilical vein endothelial cells. The uptake rate of trypan-blue and calcium and magnesium contents of endothelial cells and lactic dehydrogenase (LDH) activity in medium and malondialdhyde (MDA) content of endothelial cells were measured 60,120 and 180 min after anoxia and 30 and 60 min after reoxygenation, and the effects of 1?10 -8 mol/L CGRP on anoxic-reoxygenation endothelial cells were studied. RESULTS: The findings showed that, as anoxia prolonged, the uptake rate of trypan-blue and LDH activity and MDA content gradually elevated and, during reoxygenation, these parameters sharply increased. Calcium and magnesium levels gradually declined as anoxia prolonged, and during reoxygenation calcium content significantly increased. Meanwhile, 1?10 -8 mol/L CGRP might significantly reduce the uptake rate of trypan-blue and LDH activity and MDA content during anoxia and reoxygenation and lessen the increase in calcium content and the loss of magnesium during reoxygenation. CONCLUSION: These results showed that CGRP might have a direct protective function to endothelial cells afflicted with anoxic-reoxygenation injury by inhibiting lipid peroxidation, attenuating calcium overload and loss of magnesium and enzyme.

AIM: To investigate the effects of platelet-derived growth factor BB (PDGF-BB) on vasoconstriction of the vascular vessels. METHODS: The contractile effects of PDGF-BB at different concentrations on the rat thoracic aortic rings and the effects of verapimil, indomerthacin, phentolamine and propranolol on the response of the thoracic aortic rings were observed by using the technique of vascular perfusion in vitro, and norepinephrine was used to severe as control. RESULTS: PDGF-BB showed a remarkable contractile effect on the thoracic aorta rings of rats in a dose-dependent manner, more potent than norepinephrine at the same molar concentration. Verapimil and propranolol inhibited the contractile effect of PDGF-BB on the rat thoracic rings, but the effect of indomerthacin and phentolamine on the vasoconstriction of PDGF-BB was not observed. CONCLUSION: PDGF-BB significantly contracts the thoracic aorta rings of rats in dose-dependent and non-endothelium-dependent manners. Verapimil and propranolol inhibits the contractile effect of PDGF-BB on the rat thoracic rings.

Objective: To determine the molecular weight and p urity of porcine platelet-derived growth factor (pPDGF) and to investigate its effect on DNA synthesis of human umbilical vein endothelial cells. Metho ds: In the present experiment, the high performance liquid chromatograph y was used and the molecular weight and purity of pPDGF were studied. Human umbi lical vein endothelial cells was cultured and effects of pPDGF on DNA synthesis of endothelial cells was observed by 3H-TdR incorporation in vitro. Results: The findings of high performance liquid chromatography showed that the molecular weight of pPDGF was 29 120 and the purity was 89.46%, a nd pPDGF significantly promoted DNA synthesis of quiescent endothelial cells wit h a maximal response at a concentration of 40 ng/ml at 48 h. Conclusion: The molecular weight of pPDGF is 29 120, and it can promote DNA synthes is of cultured human umbilical vein endothelial cells.

Objective: To determine the molecular weight and purity of porcine platelet derived growth factor (pPDGF) and to investigate its effect on DNA synthesis of human umbilical vein endothelial cells. Methods: In the present experiment, the high performance liquid chromatography was used and the molecular weight and purity of pPDGF were studied. Human umbilical vein endothelial cells was cultured and effects of pPDGF on DNA synthesis of endothelial cells was observed by 3H TdR incorporation in vitro . Results: The findings of high performance liquid chromatography showed that the molecular weight of pPDGF was 29 120 and the purity was 89.46%, and pPDGF significantly promoted DNA synthesis of quiescent endothelial cells with a maximal response at a concentration of 40 ng/ml at 48 h. Conclusion: The molecular weight of pPDGF is 29 120, and it can promote DNA synthesis of cultured human umbilical vein endothelial cells. [

Objective: To investigate the effects of psycholog ical factors on treatment and outcome of patients with high altitude pulmonary e dema(HAPE). Methods: In the present study, one hundred and fifty -two patients with HAPE were tested by hospital anxiety and depression scale. Results: The results showed that there were 61 patients (40.13%) with anxiety and 29 patients (19.08%) with depression. The important factors on mental state of patients were preventive education, the first time suffering HA PE, characters of patients, degree of the disease and the medical fee, the less w ere age, sex, occupation and education of patients. Duration of rales of lung an d course of illness were significantly prolonged in HAPE patients with mental di sorders compared to the patients without mental disorder. Conclusion:The study suggests that anxiety and depression might aggravate the state of HAPE.