Melatonin protects against myocardial ischemia-reperfusion injury by inhibiting contracture in isolated rat hearts / 浙江大学学报·医学版

OBJECTIVE@#To investigate the protective effect of melatonin against myocardial ischemia reperfusion (IR) injury in isolated rat hearts and explore the underlying mechanisms.@*METHODS@#The isolated hearts from 40 male SD rats were randomly divided into 4 groups (=10): the control group, where the hearts were perfused with KH solution for 175 min; IR group, where the hearts were subjected to global ischemia for 45 min followed by reperfusion for 120 min; IR+melatonin (Mel+IR) group, where melatonin (5 μmol/L) was administered to the hearts 1 min before ischemia and during the first 5 min of reperfusion, followed by 115 min of reperfusion; and IR+2, 3-butanedione monoxime (IR+BDM) group, where the hearts were treated with BDM (20 mmol/L) in the same manner as melatonin treatment. Myocardial injury in the isolated hearts was assessed based on myocardial injury area, caspase-3 activity, and expressions of cytochrome C and cleaved caspase-3 proteins. Cardiac contracture was assessed using HE staining and by detecting lactate dehydrogenase (LDH) activity and the content of cardiac troponin I (cTnI) in the coronary outflow, measurement of left ventricular end-diastolic pressure (LVEDP) and electron microscopy. The content of ATP in the cardiac tissue was also determined.@*RESULTS@#Compared with those in the control group, the isolated hearts in IR group showed significantly larger myocardial injury area and higher caspase-3 activity and the protein expressions of cytochrome C and cleaved caspase-3 with significantly increased LDH activity and cTnI content in the coronary outflow and elevated LVEDP at the end of reperfusion; HE staining showed obvious fractures of the myocardial fibers and the content of ATP was significantly decreased in the cardiac tissue; electron microscopy revealed the development of contraction bands. In the isolated hearts with IR, treatment with Mel or BDM significantly reduced the myocardial injury area, caspase-3 activity, and protein expressions of cytochrome C and cleaved caspase-3, obviously inhibited LDH activity, lowered the content of cTnI and LVEDP, reduced myocardial fiber fracture, and increased ATP content in the cardiac tissue. Both Mel and BDM inhibited the formation of contraction bands in the isolated hearts with IR injury.@*CONCLUSIONS@#Mel can alleviate myocardial IR injury in isolated rat hearts by inhibiting cardiac contracture, the mechanism of which may involve the upregulation of ATP in the cardiac myocytes to lessen the tear of membrane and reduce cell content leakage.

Melatonin protects against myocardial ischemia-reperfusion injury by inhibiting contracture in isolated rat hearts / 南方医科大学学报

OBJECTIVE@#To investigate the protective effect of melatonin against myocardial ischemia reperfusion (IR) injury in isolated rat hearts and explore the underlying mechanisms.@*METHODS@#The isolated hearts from 40 male SD rats were randomly divided into 4 groups (=10): the control group, where the hearts were perfused with KH solution for 175 min; IR group, where the hearts were subjected to global ischemia for 45 min followed by reperfusion for 120 min; IR+melatonin (Mel+IR) group, where melatonin (5 μmol/L) was administered to the hearts 1 min before ischemia and during the first 5 min of reperfusion, followed by 115 min of reperfusion; and IR+2, 3-butanedione monoxime (IR+BDM) group, where the hearts were treated with BDM (20 mmol/L) in the same manner as melatonin treatment. Myocardial injury in the isolated hearts was assessed based on myocardial injury area, caspase-3 activity, and expressions of cytochrome C and cleaved caspase-3 proteins. Cardiac contracture was assessed using HE staining and by detecting lactate dehydrogenase (LDH) activity and the content of cardiac troponin I (cTnI) in the coronary outflow, measurement of left ventricular end-diastolic pressure (LVEDP) and electron microscopy. The content of ATP in the cardiac tissue was also determined.@*RESULTS@#Compared with those in the control group, the isolated hearts in IR group showed significantly larger myocardial injury area and higher caspase-3 activity and the protein expressions of cytochrome C and cleaved caspase-3 with significantly increased LDH activity and cTnI content in the coronary outflow and elevated LVEDP at the end of reperfusion; HE staining showed obvious fractures of the myocardial fibers and the content of ATP was significantly decreased in the cardiac tissue; electron microscopy revealed the development of contraction bands. In the isolated hearts with IR, treatment with Mel or BDM significantly reduced the myocardial injury area, caspase-3 activity, and protein expressions of cytochrome C and cleaved caspase-3, obviously inhibited LDH activity, lowered the content of cTnI and LVEDP, reduced myocardial fiber fracture, and increased ATP content in the cardiac tissue. Both Mel and BDM inhibited the formation of contraction bands in the isolated hearts with IR injury.@*CONCLUSIONS@#Mel can alleviate myocardial IR injury in isolated rat hearts by inhibiting cardiac contracture, the mechanism of which may involve the upregulation of ATP in the cardiac myocytes to lessen the tear of membrane and reduce cell content leakage.

A method for impedance measurements based on EEG acquisition system / 中国医疗器械杂志

In the bioelectric measurement, the electrode impedance detection is an important index to the signal quality evaluation and sensor electrode contact condition. In this paper, a method of accurately measuring the electrode impedance based on EEG measurement system was put forward, the method is based on the constant current source excitation signals which are added to the human body, by monitoring the human voltage to measure the electrode impedance. And different reference resistor calibration calculation in different sections was used to reduce the effect of constant current source on the precision of measurement results to improve the measurement accuracy.

Research of micro sleeping monitor and evaluation system / 中国医疗器械杂志

By studying of the pathology of human sleep and respiration disorder diseases, the method of sleep and respiration measurement, the evaluation index, a kind of micro sleep monitor and evaluation system was designed. Based on the methods of spectrum absorption and force changing, using high performance pulse oxygen saturation monitoring technology and respiration monitoring technology, developing a low-cost, high usability sleep monitor system which is convenience for family using. It can measure the signal of human oxygen saturation and chest respiration, can improve the quality of signal and reliable from arithmetic and sensor installing.

The effect of high-pass filter circuit on accurate measurement of ST-segment / 中国医疗器械杂志

The high-pass filter which is designed to overcome the polarization voltage in the ECG measurements can affect the measurement of the ST-segment; but the accuracy of the ST-segment will have an impact on the diagnosis and treatment of heart diseases. This paper used the ECG detection platform to test the effect of the high-pass filter at different frequency and studied the effect of the high-pass filter on the ST segment to ensure proper use of different application modes.

Expression and clinical significance of γH2 AX in HPV16 positive cervial squamous carcinoma / 中华微生物学和免疫学杂志

Objective To investigate the expression and significance of γH2AX in cervical squamous carcinoma.Methods Firstly,DNA were extracted from 74 cervical squamous carcinoma samples and PCR were tested for HPV infection.Secondly,formalin-fixed paraffin-embedded tissue sections (4 μm)were stained with H&E method to detect cervical lesions grading.Thirdly,HPV16 DNA were examined by in situ hybridization(ISH) and γH2AX,p16 were examined by immunohistochemical (IHC) staining.Then,30 cases typical tissue sections in which including the normal cervical tissue,cervical intraepithelial neoplasia and cervical carcinoma in situ were selected for comparing the HPV DNA loading,and the γH2AX and,pl6 expression.Finally,the feasibility of γH2AX serving as a biomarks in HPV infection-related cervical carcinogenesis were analyzed.Results In this study,HPV infection ratio is 98.65％,and HPV16 is the most common type with 74.32％ infection.In situ hybridization showed no HPV16 DNA exist in normal cervical tissues and CINI.In CIN Ⅱ HPV DNA exist mainly as episomal DNA.With the increasing of cervical lesions grade,HPV DNA was integrated into chromosome steadily.The expression of γH2AX and pl6 were positively associated with grading of cervical lesions.HPV DNA and γH2AX protein co-exist primarily in the prickle cell layer and the granular cell layer.The HPV DNA and p16 protein exist in different cell layer.Conclusion γH2AX may be employed as a biomarker for HPV positive cervical carcinogenesis.

Application of orthogonal analysis to the optimization of HPV16 E2 protein expression / 生物医学工程学杂志

This study was aimed to identify pET21b-HPV16E2/BL21(DE3) strain and to optimize the expression of human papillomavirus type 16 (HPV16) E2 protein by orthogonal analysis. Four influence factors on two levels were selected to increase the target protein quantity. The four factors were induction time, induction temperature, inductor concentration and cell density. The quantity of HPV16 E2 protein was used as the evaluation parameter. Induced by IPTG, HPV16 E2 protein was analyzed by SDS-PAGE and Western Blot. Target protein was analyzed by GIS imaging system to quantify the protein level. SPSS13. 0 software was applied to analyze the result. Data showed that the expression strain pET211rHPV16 E2/BL21(DE3) was identified correctly. HPV16 E2 protein expressed mainly at insoluble form. The 42KD protein band was identified by SDS-PAGE and Western blot. Orthogonal test was applied on influence factor analysis and expression optimization successfully. Main influence factors were inductor concentration and induction temperature. The optimimum condition of maximum expression quantity was 37 degrees C, 7h, 1.0 mmol/L IPTG and OD600 1.0. In this experiment, orthogonal test could not only be used to analyze the influential factors and promote the target protein expression, but also be used to provide a better experiment method for molecular biological study.

Construction and identification of the replication-deficient recombinant vaccinia virus co-expressing HPV type 16 L1 and L2 proteins / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To generate an HPV16 prophylactic vaccine candidate for cervical cancer.</p><p><b>METHODS</b>HPV16 major capsid protein L1 gene and minor capsid protein L2 gene were amplified using PCR. These genes were mutated by PCR site-directed mutagenesis for removal of sequence motifs (TTTTTNT) which would cause transcription termination when expressed from a vaccinia virus early promoter, then inserted into a vaccinia virus expression vector. A strain replication-deficient recombinant vaccinia virus containing the mutant sequences was obtained through a homologous recombination and identified.</p><p><b>RESULTS</b>The nucleotide sequence remained the correct amino acid sequence of the L1 and L2 proteins after mutated. Full-length L1 and L2 proteins were generated in cells infected with the recombinant virus. The virus strain propagated at very low titer or could not reproduce in some kinds of cell derived from different human tissues.</p><p><b>CONCLUSIONS</b>The authors have generated a strain replication-deficient recombinant vaccinia virus expressing HPV16 L1 plus L2 proteins as an HPV16 prophylactic vaccine candidate for cervical cancer.</p>

An experimental study of gene therapy targeted by magnetic nanosphere for occlusive vascular disease / 中国普通外科杂志

Objective To evaluate a new gene therapy for the treatment of experimental occlusive arterial disease Methods Magnetic nanospheres were produced, VEGF gene was cloned for subsequent construction of eukaryotic expression plasmid The magnetic gelatin microspheres used in targeted gene therapy were prepared by emulsion crosslinking method The microspheres were injected intrafemorally in rabbits through contralateral femoral artery, and the ischemic limb was placed in a magnetic field Angiography was performed on day 10 and day 30 respectively The capillary density and the capillary to muscle fiber ratio were determined histochemically Results Compared to the controls there was significant collateral artery development in VEGF transfected group The capillary density and the capillary to muscle fiber ratio were significantly higher for the VEGF transfected group than for the control group. The capillary density of control was (125?23)/mm 2, and in VEGF group was (298?27)/mm 2, P