Doxorubicin cardiotoxicity and Camellia sinensis cardioprotection determined by speckle-tracking echocardiography

Abstract Doxorubicin (Dox) is a medication used in the treatment of cancerous tumors and hematologic malignancies with potentially serious side effects, including the risk of cardiotoxicity. Flavonoids are plant metabolites with antioxidant properties and can be extracted from Camellia sinensis (CS). The aim of this study is to evaluate the possible cardioprotective effect of CS against injuries induced by Dox in rats. A total of 32 animals were distributed into four groups: (1) control - intraperitoneal injection (I.P.) of 0.5 mL saline weekly and 1.0 mL water by gavage daily; (2) CS - 0.5 mL saline I.P. weekly and 200 mg/kg CS by gavage daily; (3) Dox - 5.0 mg/kg Dox I.P. weekly and 1.0 mL water by gavage daily; and (4) Dox+CS -5.0 mg/kg Dox I.P. weekly and 200 mg/kg CS by gavage daily. Clinical examinations, blood profiles, electrocardiograms, echocardiograms, and histological analyses of hearts were performed over 25 days. The animals in the Dox group showed changes in body weight and in erythrogram, leukogram, electrocardiography, and echocardiography readings. However, animals from the dox+CS group had significantly less change in body weight, improved cardiac function, and showed more preserved cardiac tissue. This study demonstrated that CS prevents dox-induced cardiotoxicity, despite enhancing the cytotoxic effect on blood cells

Mechanical responses of the degenerated lumbar spines with different degrees at low frequency vibration generated by vehicle driving using finite element analysis / 中国组织工程研究

BACKGROUND; Long-term exposure to low-frequency vibration environment generated by vehicle driving is harmful to human lumbar health, and parts of drivers have suffered from lumbar degeneration. However, the damage mechanism of low-frequency vibration generated by vehicle driving on degenerated lumbar spines with different grades has not been studied clearly. OBJECTIVE; To determine the effects of low-frequency vibration on the degenerated lumbar spines with different degrees by comparing the mechanical responses of the same lumbar spine under the vibrations at different frequencies and different lumbar spines under the same vibration. METHODS; To simulate the mechanical responses of lumbar spines under low-frequency vibration, four typical finite element models of human lumbar spine with different degrees of degeneration were established, and low-frequency vibrations generated by vehicle driving were applied on these models. RESULTS AND CONCLUSION: (1) The damping effects of four lumbar spines were better under a short period of vibration, but the mechanical properties of the moderately and severely degenerated lumbar spines degraded significantly when the vibration time was long. Therefore, the drivers with moderately and severely degenerated lumbar spines were not suitable for long-term low-frequency vibration. (2) As the degree of lumbar degeneration aggravated, the lumbar natural frequency gradually decreased. (3) Excluding the resonant frequency, the changes in the mechanical properties of the same lumbar spine under the vibrations at different frequencies were tiny, suggesting that no differences in the mechanical performance of lumbar spine existed when driving on different well-paving roads in one vehicle.

Value of Duration of Myocardial Early Systolic Lengthening Assessed by Echocardiogram on Defining the Degree of Coronary Artery Stenosis / 中国循环杂志

Objectives: To evaluate the degree of coronary artery stenosis with duration of myocardial early systolic lengthening derived from 2D speckle tracking imaging (2D-STD in patients with coronary artery disease (CAD). Methods: 185 patients with suspected CAD underwent 2D-STI before coronary CT angiography (CCTA) were included in this study. Duration of myocardial early systolic lengthening, LS, RS, and CS were measured by 2D-STI. According to the results of CCTA, the myocardial segment were divided into normal group (without coronary artery stenosis), mild stenosis group(coronary artery stenosis<50%), moderate stenosis group (50%>coronary artery stenosis < 70%) and severe stenosis group (70%>coronary artery stenosis <100%). Results: Duration of myocardial early systolic lengthening, LS, RS and CS were similar between mild stenosis group and normal group (P>0.05). Duration of myocardial early systolic lengthening was increased, and LS was decreased in moderate stenosis group than in normal group (P<0.05). Duration of myocardial early systolic lengthening was increased, LS, RS and CS were significantly decreased in severe stenosis group than in normal group (P<0.01). The cutoff value of early systolic lengthening for diagnose severe stenosis was 60.0 ms (area under ROC curve [AUCl=0.91, P<0.01), with the sensitivity 85.5% and specificity 74.1%, respectively. Conclusions: Duration of myocardial early systolic lengthening is prolonged in patients with significant CAD (moderate and severe stenosis), and might be used a useful parameter to identify patients with significant CAD (moderate and severe stenosis).

Experimental evaluation of different microembolization on cardiac systolic synchronism in pigs using realtime contrast echocardiography and speckle tracking imaging / 国际生物医学工程杂志

Objective To study the influence of different microembolism on left ventricular systolic synchronism in pigs by detecting the real-time dypyridamole stress contrast echocardiography (RT-MCE).Methods Eighteen miniature pigs were randomly divided into three groups and underwent microembolization injection procedure through the middle of anterior descending coronary artery with different numbers of microsphere injection,as:group A(dosage 50 thousands,3 pigs),group B (dosage 120 thousands,8 pigs) and group C (dosage 150 thousands,7 pigs).The peak values and the time-to-peak circumferential strain(Circ.Strain),radial velocity (Radial Vel.) and radial strain (Radial Strain) were obtained both at mitral valve level and papillary muscle level at left ventricle short axis views using two-dimensional speckle tracking imaging(STI)analyzed by Philips Q-Lab 8.1 workshop,respectively.Results No significant difference in the presence of contraction synchrony was observed using RT-MCE.The time-to-peak Circ.Strain of microembolism related segments were prolonged at 1 week after microembolism detecting with dypyridamole stress RT-MCE (P＜0.05,both intro-group and inter-group).While time-to-peak radial strain were extended since 6 hours after the intervention to 1 week after the procedure.Conclusions Dypyridamole stress RT-MCE can be used to measure the myocardial perfusion accurately.The elongation of time-to-peak circ.strain and radial strain were developed with time in microembolism related segments.