Objective To evaluate the effect of resveratrol on the growth of an established A431 xenogratt tumor in nude mice.Methods The model of human skin squamous cell carcinoma was established by inoculating A431 cells in log-phase growth into the left axillary fossa of Balb/c (nu/nu) nude mice.After 7-8 days,60 mice bearing human A431 skin squamous cell carcinoma xenografts were randomly and equally divided into 6 groups:blank control group receiving no treatment,negative control group treated with intraperitoneal sodium chloride physiological solution,positive control group treated with intraperitoneal cyclophosphamide,high-,medium-and low-dose resveratrol groups treated with intraperitoneal resveratrol of 40,20 and 10 μg per gram body weight per day,respectively.Tumor size was measured at a 4-day interval during the treatment course.After 14-day treatment,the mice were sacrificed.Xenograft tumors were removed from these mice and subjected to weight measurement,pathological examination by hematoxylin and eosin (HE) staining and apoptosis detection by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL).Western blot was conducted to quantify the protein expression of apoptosis-related factors,including phosphorylated extracellular signal-regulated protein kinase (p-ERK),p53 and caspase 3.Data were processed by SPSS 13.0 software,and statistical analysis was carried out by analysis of variance and Pearson correlation analysis.Results By the end of treatment,the xenograft tumor volume was (1153.56 ± 255.41) mm3,(1001.69 ± 115.08) mm3,(1206.80 ± 175.88) mm3,(1342.28 ± 211.12) mm3,(1642.34 ± 225.85) mm3 and (1564.32 ± 156.49) mm3,and the weight was (1.84 ±0.30) g,(1.72 ± 0.39) g,(1.96 ± 0.40) g,(2.67 ± 0.73) g,(3.16 ± 0.52) g,and (3.33 ± 0.59) g,respectively in the positive control group,high-,medium-and low-dose resveratrol group,negative control group and blank control group.Significant differences were observed in the xenograft tumor volume (F =16.00,P ＜ 0.05) and weight (F =19.15,P ＜ 0.05) among the 6 groups.According to the tumor weight,the growth of tumor was inhibited by 45.57％,37.97％ and 15.51％ respectively in the high-,medium-and low-dose resveratrol groups.Increased apoptotic index was observed in the positive control group,high-,medium-and low-dose resveratrol groups compared with the negative control group and blank control group (36.79 ± 8.86,33.15 ± 6.00,18.09 ±3.92 and 10.53 ± 4.20 vs.3.87 ± 1.63 and 2.73 ± 1.61,F =93.26,P ＜ 0.05).Analysis of variance showed that the protein expressions of p-ERK,p53 and caspase 3 were all higher in the three resveratrol groups than in the negative control group and blank control group (F =6.65,6.78,11.56,respectively,all P ＜ 0.05).The protein expression of p53 was statistically correlated with p-ERK (r =0.68,P ＜ 0.05) and caspase 3 (r =0.56,P ＜0.05).Conclusions Resveratrol shows an inhibitory effect on the growth of human A431 skin squamous cell carcinoma xenografts in nude mice,likely by increasing p53 expression and inducing tumor cell apoptosis via the activation of MAPK/ERK pathway.

In this paper, to analyze the functional influence of ischemia on cardiac cell electrical activity and subsequently on ventricular electrical wave conduction, a human ventricular ischemic model was developed, which took into account three major pathophysiological components of ischemias hyperkalaemia, acidosis, and anoxia. This model simulated the action potential (AP) propagations of endocardial, midmycardial and epicardial cells with different levels of ischemia, and the influence of each factor on cell AP was analyzed. Finally the ECG waveform under ischemia was quantified by using a 2D model of human left ventricular tissue based on the anatomical structure of human heart. The experimental results showed that under ischemia action potential durations (APD) were reduced. In most cases, the larger the size of ischemic region or the more severe the ischemic level, the more dramatic the changes in the amplitude of ST-T wave were observed. For the three components of ischemia, hyperkalaemia was the dominant contributor to ST-T wave changes, which was in agreement with the results obtained on animal models.
Action Potentials ; physiology ; Computer Simulation ; Electrocardiography ; Heart Ventricles ; physiopathology ; Humans ; Hyperkalemia ; physiopathology ; Models, Cardiovascular ; Myocardial Ischemia ; physiopathology

Pacemaking dysfunction has become a significant disease that may contribute to heart rhythm disorders, syncope, and even death. Up to now, the best way to treat it is to implant electronic pacemakers. However, these have many disadvantages such as limited battery life, infection, and fixed pacing rate. There is an urgent need for a biological pacemaker (bio-pacemaker). This is expected to replace electronic devices because of its low risk of complications and the ability to respond to emotion. Here we survey the contemporary development of the bio-pacemaker by both experimental and computational approaches. The former mainly includes gene therapy and cell therapy, whilst the latter involves the use of multi-scale computer models of the heart, ranging from the single cell to the tissue slice. Up to now, a bio-pacemaker has been successfully applied in big mammals, but it still has a long way from clinical uses for the treatment of human heart diseases. It is hoped that the use of the computational model of a bio-pacemaker may accelerate this process. Finally, we propose potential research directions for generating a bio-pacemaker based on cardiac computational modeling.