BACKGROUND: The implantation of electronic devices has become the preferred treatment tor symptomatic bradyarrhythmias.However,there are many shortcomings in electronic pacemakers.The usage of molecular biology principle to develop biological pacemaker has become a topic of discussion in research.When sinoatrial node is lnhlblted,pacemaker effect runs by transfecting hyperpolarization-activated cyclic nucleotide-gated(HCN)channel gene of If current,overexprcssing HCN,and increasing inward current in diastolic phase of the heart.Construction of biological pacemakefs by gene therapy and cell therapy may become an optimal substitute of electronic pacemakers in the near future.OBJECTIVE:To sum up the research advancement in application of HCN channel gene to the development of biological pacemaker.RETRIEVAL STRATEGY:The relevant articles published between January 1979 and June 2007 were searched for in Pubmed database by researcher of this article with the key words of"hyperpolarization-activated cyclic nucleotide-gated chartnel,biological pacemaker"in English.157 articles were selected and reviewed by the inclusive cntena of:① articles closely related with the application of HCN to the development of biological pacemaker;②the late articles and articles in anthority journals in the same field.Exclusive criterion:repetitive studies.LITERATURE EVALUATION:The main sources of literatures were randomized clinical trial(RCT)on biological pacemaker by HCN.Among 36 selected articles,10 were reviews,and others were elementary expenInental studles.DATA SYNTHESIS:①Of all four HCN isoforms,HCNI,HCN2,and HCN4 are the main isoforms in the heart.HCN3 only expresses in embryonic pacemaker cells in a low level.HCN2 highly expressed in low pacing regions(Ventricular muscle),whereas HCN4 highly expressed in high pacing regions.Moreover,HCN2 are the main isoforms in the ventricle.Expression ratio of HCN2 to HCN4 is 5:1 in neonate rats and 13:1 in adult rats.②Defects in HCN channels may underlie sick-sinus syndrome.③Up to now,HCN genes of If current contribute importantly to the generataon of the regular pacemaker potential.CONCLUSION:Gene therapy and cell therapy have become an optimal approach to improve biological paccmakers.Application of HCN channel gene in development of biological pacemaker may hold great promlse In the treatment of chronic arhythmia.

Survivin is a member of the IAP family, which has been shown to localize to various components of the mitotic apparatus. Survivin is not only an apoptosis inhibitor, but a mitotic regulator as well. Survivin is Absolutely undetectable in normal tissues, but over-expressed in all the most common human cancers. Survivin is considered as an important target in cancer treatment, and the research on its molecular antagonists has gained encouraging achievements.

To investigate the relationship of the expressions of matrix metalloproteinases(MMPs) and tissue inhibitor of metalloproteinase (TIMP) with metastasis and prognosis in colorectal cancer. Using S P immunohistochemistry method to detect the expressions of MMPs and TIMP in 41 cases of colorectal cancer. The expression levels were analyzed quantitatively by computer image analysis system. The results showed that the expression of MMP 2,MMp 9 and TIMP 1 was higher than those in normal epithelial mucosa. In the cases with metastasis to lymph node, the expressions of MMP 2 and MMP 9 TIMP 1 were significantly higher than that of cases without metastasis.The high expressions of the three factors are closely correlated with the progression and poor prognosis of colorectal cancer. It suggested that expressions of MMPs and TIMP are closely related with metastasis and prognosis in colorectal cancer.

56 school-aged children with epilepsy and 37 normal ones of the same gender,age and educational level were selected. All the subjects' parents completed the child adaptive behavior scale, the mutiple stepwise linear re-gression was used to explore the impact of epilepsy related factors on social adaptive function. The social adaptive function of school-aged children with epilepsy faulty is affected by seizure frequence,gender,age,epilepsy control, clinical course,and the number of antiepileptic drugs.

NG-nitro-D-arginine (D-NNA) produced pressor responses in rats by acting via chiral inversion intoNG-nitro-L-arginine (L-NNA), an inhibitor of nitro oxide synthase. The present investigation aimed to study the roleof the D-amino acid oxidase (DAAO) in chiral inversion of D-NNA and the relationship between DAAO activitieson various D-amino acids and their inversion rate. Benzoate (400 mg/kg) or creatinine (400 mg/kg), two inhibitorsof DAAO, blocked D-NNA-induced pressor responses in rats. Furthermore, the addition of the pure DAAOsignificantly potentiates L-NNA production rate in kidney homogenates by approximately 2-folds. The in vivo andin vitro results suggested that DAAO plays an essential role in the pressor responses elicited by D-NNA.Moreover, crude DAAO solution from the kidney showed marked selection (the maximal ratio of Kcat/Km wasnearly 15 times) on different D-amino acids that exhibited similar chiral inversion rate in vivo, suggesting that otherenzymes, such as transaminase, are also required for the entire process of D-NNA chiral inversion.

Objective To evaluate the teaching activity on public health courses from clinical medical students in our university in order to provide a scientific basis for improving the curriculum design and teaching reform. Methods The “Questionnaire on Teaching Evaluation in Public Health Courses”, including teaching attitude, teaching content, teaching methods and teaching effectiveness was designed, and a general investigation was conducted among the clinical medical students of five-year program (840 students) and eight-year program (278 students) in these three aspects to under-stand students' evaluation to the course, who had finished the public health courses, including Preven-tive Medicine, Medical Statistics and Epidemiology (hereinafter referred to as: statistics, epidemiology, prevention) in Sun Yat-sen University. Statistical analysis was made using SPSS 13.0 software. Data analysis methods contain descriptive analysis, T-test, ANOVA, LSD, SNK, hierarchical logistic regres-sion analysis, etc. Results The overall score of teaching evaluation is (4.04±0.60). Differences exist between the evaluation in the five-year medical students and the eight-year medical students. The P values were 0.000 (Medical Statistics), 0.269 (Epidemiology), 0.047 (Preventive Medicine). The com-parison of scores among the four dimensions shows: Teaching effectiveness < Teaching methods β' effectiveness. Conclusions Clinical Medical students' overall evaluation on the public health courses offered by this university was good. Teaching effectiveness and teaching methods still need improvement. Teaching contents are the most influential factor of overall teaching satisfaction, followed by teaching effectiveness.

Objective To observe the changes in cytokines, oxygen free radicals, acidulous production in serum and to investigate the effectiveness of monitoring metabolism of cells and the method for evaluating cell injury in patients with severe trauma. Method The detailed data of 117 patients rescued and managed carefully from May 2005 to February 2007 were assessed and stratified with ISS and APACHE Ⅱ , and the serum levels of arterial blood lactate(ABL) ,base deficit(BD) ,superoxide(SOD) ,lipid peroxide(LPO) ,TNF-α and IL-6 were measured in real-time according to the condition of the patient. Results The monitoring biomarkers obviously changed with injury severity which endangered the situation of patients after trauma (P < 0.05) , especially in the patients with ischemia , hypoxia, shock, iniection, SIRS, and MODS (P < 0.01). The persistence of extremely elevated levels of biomarkers meant the organ failure and fatality of patients after trauma, and there was a obvious differece between those cases and cases without elevation of biomarkers ( P < 0.01). Conclusions The outcome of patients after trauma is closely correlated with injury severity,infection and MODS,and the levels of biomarkers including ABL, SOD, IPO, TNF-a and IL-6 are useful indicators of outcome measure.

Objective To evaluate the physiological variables,which precisely and reliably reflected the effect of emergency fluid therapy for severely traumatized patients, in order to set up the ultimate criteria of optimal goal in fluid resuscitation. Method A total of 149 patients with severe trauma were given fluid resuscitation and were stratified into 3 groups with different severities of trauma as per ISS (injury severity score) and APACHE Ⅱ . Of all patients, heart rate (HR), systolic blood pressure (SBP), oxygen saturation of arterial blood (SaO2), blood gas analysis, arterial blood lactate (ABL), oxygen saturation of central venous blood (SCVO2) or oxygen saturation of mixed venous blood (SVC2), urine output, base excess (BE) and oxygenation index (OI = PaO2/FiO2) were measured and calculated. These variables were compared between groups to find out the significant differences and the relationship to response time to fluid therapy as well as complications and outcomes. Results Within 24 hours of fluid resuscitation, 127 patients reached the therapeutic goal in respect of systemic hemodynamics improved including the variables of SBP, HR and urine output, and the optimal goal of fluid therapy in 112 patients was estimated with cellular oxygen available found in the levels of ABL, BE and OI measured. These two sets of criteria (clinical signs vs laboratory findings) for determining the therapeutic goal showed significant difference in length of time taken for reaching the goal of treatment ( P < 0.05). There were significant differences in APACHE Ⅱ scores between those reaching the therapeutic goal within 24 hours and those taking longer time over 24 hours reaching the therapeutic goal or the death (P < 0.01). The duration of persistence in abnormal systemic hemody-namics and laboratory findings was longer in patients with complications or injured to death than that in survivors (P <0.05 -0.01). Conclusions In addition to the stability of vital signs, tissue perfusion and cellular oxy-genation should be taken as ultimate criteria of successful fluid resuscitation for severely traumatized patients judged by means of measuring the ABL, BE and OI variables.

Objective To evaluate the safety and efficacy of the temporary bedside cardiac pacing in controlling torsades de points (TdP) in patients with acquired long QT syndrome (LQTS). Methods Twelve patients with acquired LQTS were enrolled from April 2003 to August 2007 consecutively and their clinical data were analyzed. Bedside cardiac pacing was adopted when other methods couldn't terminate the repeated TdP. Results Twelve patients successfully experienced the temporary bedside cardiac pacing via femoral venous. The average time spent in bedside cardiac pacing was about (10.5±2.4) min. After cardiac pacing the interval of QT and QTc were shortened [ (0.42±0.03 ) svs (0.52±0.06) s, P < 0.05; (0.43± 0.04 ) s vs (0.53±0.05 ) s, P <0.05 ]. The TdP occurred (4.6±1.2 ) times per day before cardiac pacing and it didn't reoccur any more after bedside cardiac pacing. The average time for cardiac pacing was(3.8±1.4) d. When the patients were discharged, the interval of QT and QTe were (0.41±0.02) s and (0.42±0.05) s respectively, there were significant differences compared with that before cardiac pacing(P< 0.05). During 1 year follow-up, the patients didn't experience TdP any more, and the interval of QT and QTe were (0.41± 0.06) s and (0.42±0.05) s respectively. Conclusion The immediate bedside cardiac pacing is a safe and effective way to control the repeated TdP.