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Open access

Russel Reiter, Sergio Paredes, Ahmet Korkmaz, Mei-Jie Jou and Dun-Xian Tan

Melatonin combats molecular terrorism at the mitochondrial level

The intracellular environmental is a hostile one. Free radicals and related oxygen and nitrogen-based oxidizing agents persistently pulverize and damage molecules in the vicinity of where they are formed. The mitochondria especially are subjected to frequent and abundant oxidative abuse. The carnage that is left in the wake of these oxygen and nitrogen-related reactants is referred to as oxidative damage or oxidative stress. When mitochondrial electron transport complex inhibitors are used, e.g., rotenone, 1-methyl-1-phenyl-1,2,3,6-tetrahydropyridine, 3-nitropropionic acid or cyanide, pandemonium breaks loose within mitochondria as electron leakage leads to the generation of massive amounts of free radicals and related toxicants. The resulting oxidative stress initiates a series of events that leads to cellular apoptosis. To alleviate mitochondrial destruction and the associated cellular implosion, the cell has at its disposal a variety of free radical scavengers and antioxidants. Among these are melatonin and its metabolites. While melatonin stimulates several antioxidative enzymes it, as well as its metabolites (cyclic 3-hydroxymelatonin, N1-acetyl-N2-formyl-5-methoxykynuramine and N1-acetyl-5-methoxykynuramine), likewise effectively neutralize free radicals. The resulting cascade of reactions greatly magnifies melatonin's efficacy in reducing oxidative stress and apoptosis even in the presence of mitochondrial electron transport inhibitors. The actions of melatonin at the mitochondrial level are a consequence of melatonin and/or any of its metabolites. Thus, the molecular terrorism meted out by reactive oxygen and nitrogen species is held in check by melatonin and its derivatives.

Open access

Gaofa He, Jie Meng, Renbing Tan and Peng Zhong

Abstract

A home-made electrostatic force microscopy (EFM) system is described which is directed toward assessment of the microscopic geometry of the surface of specimens made of non-conductive material with a large thickness. This system is based on the variation in the electrostatic force between the conductive probe and the non-conductive specimen in order to get its surface morphology. First, based on the principle of dielectric polarization, the variation rules of the electrostatic force between the charged probe and the non-conductive specimen were studied. Later, a special tuning fork resonant probe unit made of quartz crystal was fabricated for measurement of the electrostatic force, and the scanning probe microscopic system in the constant force mode was constructed to characterize the three-dimensional micro-topography of the surface of the specimen. Finally, this system was used to perform scanning measurement experiments on the indented surface of the specimen made of the polyvinyl chloride (PVC) material with thickness 3 mm. In the present experimental system, when the external voltage was 100 V and the distance from the probe tip to the specimen surface approximately 100 nm, the variance in the resonant frequency of the probe unit was around 0.5 Hz. These results indicate that this home-made EFM system can effectively characterize the micro-topography of the non-conductive specimen with very large thickness which is above several millimeters.

Open access

Yanping Tan, Wen Hu, Xin Xu, Jie Zhou, Chuntai Wang, Xuequn Liu and Gang Cheng

Abstract

In vitro embryogenic callus is a critical factor for genetic transformation of rice, especially for indica varieties. In this study, we investigated the relationship between polyamines, including putrescine (Put), spermidine (Spd) and spermine (Spm), and callus browning, and we studied the effect of exogenous Put on callus regeneration and on the content of endogenous polyamines. In addition, the expression levels of arginine decarboxylase gene (Adc1) and S-adenosylmethionine decarboxylase gene (Samdc) in embryogenic callus were studied by quantitative Real-time PCR analysis. The results showed that the contents of endogenous Put and Spd in the browning callus were significantly lower than those in normal callus. Exogenous Put could effectively improve the growing state of callus of indica rice and enhance the development of embryogenic callus. The content of endogenous polyamines in embryogenic callus, especially Spd and Spm, was increased after addition of exogenous Put. Additionally, exogenous Put also had an obvious impact on the expression levels of Adc1 but partial effect on the expression levels of Samdc gene. This study could increase the knowledge of both embryogenic callus induction and polyamine catabolism in callus in indica rice.

Open access

Jing Shen, Xiao-Ming Lei, Yang Song, Xing Tan, Qin Liu, Li-Wen Dai and Jie Yu

Abstract

Objective: To observe the effects of electro-acupuncture (EA) on GRP78 and Caspase-12 gene expression in rats with ischemia- reperfusion injury (IRI) by stimulation on Nei Guan (PC6) and Bai Hui (GV20) points, so that to understand whether or not the protective effects of acupuncture is related to endocytoplasmic reticulum (ER) stressapoptosis passage.

Methods: 50 rats were randomly assigned to five groups (10 in each group): normal control(A), pseudo-operation(B), operation(C), Edaravone(D) and EA(E). The ischemia/reperfusion model of middle cerebral artery occlusion (MCAO) was established by suture embolic method. TUNEL staining method was employed to measure the apoptosis index of nerve cells in rats. Real-time polymerase chain reaction (RT-PCR) was employed to measure the mRNA expression of GRP78 and Caspase-12.

Results: Compared with normal group and pseudo-operation group, the apoptosis indexes and mRNA expression of GRP78 and Caspase-12 in operation group, Edaravone group and EA group were increased, with statistical significance(P<0.05 or P<0.01); compared with operation group, the apoptosis indexes and Caspase-12 mRNA expression in Edaravone group and EA group were decreased(P<0.05 or P<0.01), but GRP78 mRNA expression were increased(P<0.01); there were no significant difference between Edaravone group and EA group on the above indexes(P>0.05).

Conclusion: Acupuncture on Nei Guan and Bai Hui points could effectively suppress the nerve cell apoptosis in cerebral ischemia. The underlying mechanism might be related to upregulation of the ERS-protective GRP78 expression and downregulation of apoptosis-promotion Caspase-12 expression.

Open access

Rong Tan, De-Ying Hu, Yan-Hong Han, Yi-Lan Liu, Xiao-Ping Ding, Shu-Jie Wang and Ke Xu

Abstract

Objective

The aim of this study was to explore the characteristics of and preventive management strategies for suicidal inpatients in a general hospital.

Methods

A total of 54 suicide victims were drawn from a patient safety adverse event network reporting system during hospitalization in a general hospital from November 2008 to January 2017.

Results

Subjects who committed suicide in the general hospital were women and those who suffered from malignant neoplasms during general hospital treatment. Furthermore, most of the patients who committed suicide used more violent suicide methods. The most common and lethal means was jumping from heights at the windowsill.

Conclusions

It is concluded that management strategies for suicide prevention can be provided from the aspects of patients, medical staff and the hospital environment. It is not only urgent but also feasible to reduce the suicide rate of inpatients and further improve hospital safety management.