Porcine Epidemic Diarrhoea Virus Induces Cell-cycle Arrest through the DNA Damage-signalling Pathway.

INTRODUCTION: Porcine epidemic diarrhoea virus (PEDV) infection causes watery diarrhoea, vomiting, anorexia, and weight loss, especially among neonatal piglets, inflicting on them morbidity and mortality potentially reaching 90%-100%. Despite it being known that certain mammalian cell phases are arrested by PEDV, the mechanisms have not been elucidated, and PEDV pathogenesis is poorly understood. This study determined the effect of an epidemic PEDV strain on cell cycle progression. MATERIAL AND METHODS: We observed the effect of the PEDV SHpd/2012 strain on an infected Vero cell cycle through flow cytometry and Western blot, investigating the interrelationships of cell-cycle arrest, the DNA damage-signalling pathway caused by PEDV and the phosphorylation levels of the key molecules Chk.2 and H2A.X involved upstream and downstream in this pathway. RESULTS: PEDV induced Vero cell-cycle arrest at the G1/G0 phase. The phosphorylation levels of Chk.2 and H2A.X increased with the prolongation of PEDV infection, and no significant cell-cycle arrest was observed after treatment with ATM or Chk.2 inhibitors. The proliferation of PEDV was also inhibited by treatment with ATM or Chk.2 inhibitors. CONCLUSION: PEDV-induced cell-cycle arrest is associated with activation of DNA damage-signalling pathways. Our findings elucidate the molecular basis of PEDV replication and provide evidence to support further evaluation of PEDV pathogenesis.

Cloning, expression and biochemical characterization of recombinant superoxide dismutase from Antarctic psychrophilic bacterium Pseudoalteromonas sp. ANT506.

In this study, a superoxide dismutase gene (PsSOD) from Pseudoalteromonas sp. ANT506 was cloned and over expressed in Escherichia coli. The PsSOD has an open reading frame of 582 bp with a putative product of 193 amino acid residue and an estimated molecular size of 21.4 kDa. His-tagged PsSOD was subsequently purified 12.6-fold by Ni-affinity chromatography and the yield of 22.9%. The characterization of the purified rPsSOD exhibited maximum activity at 30 °C and pH 8.0. The enzyme exhibited 13.9% activity at 0 °C and had high-thermo lability at higher than 50 °C. rPsSOD exhibited well capability to 2.5 M NaCl (62.4%). These results indicated that rPsSOD exhibited special catalytic properties.

Power enhancement of piezoelectric transformers by adding heat transfer equipment.

It is known that piezoelectric transformers have several inherent advantages compared with conventional electromagnetic transformers. However, the maximum power capacity of piezoelectric transformers is not as large as electromagnetic transformers in practice, especially in the case of high output current. The theoretical power density of piezoelectric transformers calculated by stress boundary can reach 330 W/cm(3), but no piezoelectric transformer has ever reached such a high power density in practice. The power density of piezoelectric transformers is limited to 33 W/cm(3) in practical applications. The underlying reason is that the maximum passing current of the piezoelectric material (mechanical current) is limited by the temperature rise caused by heat generation. To increase this current and the power capacity, we proposed to add a thermal pad to the piezoelectric transformer to dissipate heat. The experimental results showed that the proposed techniques can increase by 3 times the output current of the piezoelectric transformer. A theoretical-phenomenological model which explains the relationship between vibration velocity and generated heat is also established to verify the experimental results.

Analyses of the heat dissipated by losses in a piezoelectric transformer.

In this paper, a new approach to the thermal management of piezoelectric transformers is proposed. Starting from the electromechanical equations, including mechanical and dielectrical losses, and knowing the piezoelectric material characteristics, an analytical model was developed and the theoretical profile of the heat sources was deduced. To check these theoretical points of view, a thermal characterization of a Rosen-type piezoelectric transformer was done. The temperature field on the surface of the PT was measured in thermal transient steps. Knowing the specific temperature, the experimental heat sources were obtained. As expected, they are related to the square modulus of the strain or stress profiles on the one hand and to mechanical losses on the other, which confirms the theoretical results. Experimental data and calculation results are matched for several resistance loads and frequencies tested.

Pulse wave velocity as a marker of arteriosclerosis and its comorbidities in Chinese patients.

To obtain reliable data on the epidemiology of arteriosclerosis and the comorbidities in patients with hypertension (HP), coronary heart disease (CHD), type 2 diabetes mellitus (T2DM) and stroke, we evaluated the clinical significance of pulse wave velocity (PWV) as an indicator of arteriosclerosis and its comorbidities in Chinese patients. A total of 910 subjects, including 748 Chinese patients with one or more cardiovascular risk factors (80.2% male, mean age 73.69+/-5.03 years) and 162 healthy volunteers (78.4% male, mean age 73.60+/-5.32 years) were recruited into the study. PWV was measured in 910 subjects, and large artery arteriosclerosis was defined as PWV >or=12 m/s. Multivariable logistic regression analyses were performed to identify risk factors associated with arteriosclerosis. The prevalence of large artery arteriosclerosis in the patients overall was 67.4%, and the prevalence was higher in patients with than in those without HP (63.3% vs. 34.0%; odds ratio [OR]: 3.451), T2DM (24.8% vs. 11.1%; OR: 2.854), CHD (56.1% vs. 45.1%; OR: 1.246) and stroke (26.6% vs. 19.2%; OR: 1.236), but the OR values of CHD and stroke did not differ significantly (p>0.05). After multiple logistic regression analysis, female sex, older age, HP and T2DM were risk factors for large artery arteriosclerosis. In conclusion, PWV can be used as a routine measurement to scan arteriosclerosis in patients with HP or T2DM.

[Determination of the aortic pulse wave velocity in 545 healthy subjects].

OBJECTIVE: To understand the aortic pulse wave velocity (PWV) in mid-aged and elderly populations and to study the correlation between gender and PWV and the tendency of PWV on different age groups. METHODS: According to the clinical trial guideline, we selected 545 healthy subjects (age, 31-85 years, 395 men and 150 women), and measured carotid-femoral PWV, using Complior. RESULTS: The average value of PWV in Chinese healthy subjects was 11.62 +/- 2.97 m/s. There was no significant difference in the PWV values between males and females who were older than 40 years, but the values of PWV were lower in females than in males in the 30-39 year-old group. PWV was positively correlated with age. In the present study, the reference values of PWV were established in the different age groups, based on the regression equations between PWV and age. CONCLUSION: Aortic pulse wave velocity seemed to be influenced by age but hardly influenced by gender in healthy subjects, so that the reference value of PWV should be established according to the different age groups. When aorta got stiffer, the value PWV got larger accordingly when age was increasing.