This paper analyzed the current scientific research situation of medical postgraduates in Xi'an Jiaotong university,stated briefly the existing main problems and relevant influence factors including poor scientific research ability due to low quality enrollment,unreasonable construction of experimental platform,patchy quality of tutor teams et al.To solve the problems above,several policies were proposed,mainly including strengthening basic experimental skills of medical undergraduates,reforming the postgraduate curriculum system,optimizing the building of experimental platform and reinforcing the development of tutor teams.

Objective To investigate the effects of adenosine (Ado) on myocardiac electrophysiology in simulated ischemia and reperfusion in guinea-pig ventricular myocytes. Methods Electrical activity was recorded using standard intracellular microelectrode technique. Right ventricle was superfused with simulated ischemic Tyrode's solution for 15 min, and reperfued with normal Tyrode's solution for 30 min. Results The results showed Ado had no measurable effects on guinea-pig ventricular myocytes in normal Tyrode's solution. In the presence of Ado, maximal diastolic potential tended to be more depolarized during ischemia, and action potential (AP) parameters were abbreviated greatly in a concentration-dependent manner. Especially, the concentration of Ado 100 μmol·L-1 had significant effects on AP parameters in ischemic phase [APD30, APD50, and APD90 reduced by (86 ± 8) ％ versus (65± 6) ％, (70± 7)％versus (50±6)％, and (60±6)％versus (42±4)％ for control after 15 min, P＜0.05]. During reperfusion, AP parameters did not completely return to initial values in presence of Ado. This study illustrated that Ado significantly decreased incidence of arrhythmias induced by ischemia and reperfusion (in presence of Ado 100 μmol·L-1, the incidence of DAD decreased by 17％ versus 82％ for control during reperfusion). Conclusion Ado has no significant effects on guinea-pig ventricle in normal conditions, abbreviates greatly AP parameters during ischemia with a concentration-dependent manner, and has marked antiarrhythmic effects in ischemia and reperfusion.

Objective To study the effects of ghrelin on action potential (AP) and transient outside K+ current (Ito) in ventricular myocytes of diabetic cardiomyopathy (DCM) rats.Methods A rat model of DCM was established by single intraperitoneal injection of streptozotocin (STZ, 60mg/kg), and whole cell patch-clamp technique was used to record the effects of 10-7mmol/L ghrelin on AP and Ito current density in the DCM rat ventricular myocytes.Results Compared to DCM group, Ghrelin of 10-7mmol/L could significantly prolong APD50 [(12.49±2.32)％;n=7, P=0.037] and APD90 [(26.29±5.13)％;n=7, P=0.006] and decrease Ito current peak value [(23.14±3.07)％;n=9, P=0.021] in DCM rat ventricular myocytes.Conclusion Exogenous ghrelin is involved in the electrophysiological reconstruction of the heart of diabetic rats by decreasing Ito current and prolonging APD in STZ-induced DCM rat ventricular myocytes.

Purpose: The human epidermal growth factor receptor 2 (HER2) is an established therapeutic target for various kinds of solid tumors. HER2 amplification occurs in approximately 1% to 6% of colorectal cancer. In this study, we aimed to assess the efficacy and safety of trastuzumab in combination with chemotherapy in HER2-positive metastatic colorectal cancer (mCRC). Materials and Methods: An open-label, phase II trial (Clinicaltrials.gov: NCT03185988) was designed to evaluate the antitumor activity of trastuzumab and chemotherapy in HER2-positive digestive cancers excluding gastric cancer in 2017. Patients from this trial with HER2-positive, KRAS/BRAF wild-type, unresectable mCRC were analyzed in this manuscript. Eligible patients were treated with trastuzumab (8 mg/kg loading dose and then 6 mg/kg every 3 weeks) and irinotecan (120 mg/m2 days 1 and 8 every 3 weeks). The primary endpoint was the objective response rate. Results: Twenty-one HER2-positive mCRC patients were enrolled in this study. Seven patients (33.3%) achieved an objective res-ponse, and 11 patients (52.4%) had stable disease as their best response. The median progression-free survival (PFS) was 4.3 months (95% confidence interval, 2.7 to 5.9). Four of the 21 patients (19.0%) had grade 3 adverse events, including leukopenia, neutropenia, urinary tract infection, and diarrhea. No treatment-related death was reported. Exploratory analyses revealed that high tumor tissue HER2 copy number was associated with better therapeutic response and PFS. Alterations in the mitogen-activated protein kinase pathway, HER2 gene, phosphoinositide 3-kinase/AKT pathway, and cell cycle control genes were potential drivers of trastuzumab resistance in mCRC. Conclusion Trastuzumab combined with chemotherapy is a potentially effective and well-tolerated therapeutic regimen in mCRC with a high HER2 copy number.

【Objective】 To investigate the central sedative and hypnotic effects and mechanisms of Shumian Capsule. 【Methods】 The blank control group, the positive drug diazepam group, and the low-, medium-, and high-dose groups of Shumian Capsule were designed in the experiments. Male Kunming mice were administered orally by gavage. We conducted the experiment of mouse autonomous activity, and assessed supra- and sub-threshold dose sleep with pentobarbital sodium, respectively. The levels of γ-aminobutyric acid (GABA) and glutamic acid (Glu) in the brain tissue of the mice were measured by enzyme-linked immunosorbent assay (ELISA) or colorimetric method. Male SD rats were injected intraperitoneally with p-chlorophenyl alanine [PCPA, 350 mg/(kg·d)] to establish an insomnia rat model, after which rats were continuously administered intragastrically for 7 days. The general status and body weight of the rats were observed. Total distance and standing times of rats were measured by open field test. Western blotting and immunohistochemistry assays were used to evaluate the protein expression of 5-HT1A receptor (5-HT1AR) in the rat hippocampus. 【Results】 Compared with the blank control group, the three dose groups of Shumian Capsule [1.6, 3.2, 6.4 mg/(kg·d)] for 14 consecutive days had significantly reduced the number of spontaneous activities and standing times in the mice (P<0.01). The high dose significantly prolonged the sleep duration of the mice induced by the supra-threshold dose of pentobarbital sodium (P<0.01). Compared with the blank control group, each dose group of Shumian Capsule had an increased GABA level in the mouse brain tissue in a dose-dependent manner (P<0.05); the medium- and high-dose groups had significantly reduced Glu levels in the hippocampus (P<0.05), while the high-dose group had significantly reduced Glu level in the cortex (P<0.05). In insomnia model rats, their activity was sluggish; their circadian activity rhythm disappeared; the hair became hard, rough and dull, with severe hair loss; and their weight reduced. After 7 consecutive days of the drug administration, the rats’ mental state in each Shumian Capsule dose group was improved. Compared with the blank control group, the rats’ body weight gains were significantly reduced after intraperitoneal injection of PCPA (P<0.01). Compared with the model group, each rat group of Shumian capsule treatment had significantly increased body weight gains (P<0.01). Compared with the blank control group, the distance of the rats in the model group increased in the open field test, and the expression level of 5-HT1AR protein in the hippocampus decreased. However, the distance of rats in diazepam group and each dose group of Shumian Capsule was significantly reduced (P<0.01), and the expression level of 5-HT1AR protein in the hippocampus of the high- and medium-dose groups of Shumian Capsule and diazepam group increased significantly (P<0.01). 【Conclusion】 Shumian Capsule has obvious effects of sedation, hypnosis and insomnia improvement, and its underlying mechanisms may be related to the increased GABA and decreased Glu contents in brain tissues, as well as up-regulated 5-HT1AR protein expression in the hippocampus.