Objective To evaluate the application effect of‘incorrect cases’in medical statis-tics teaching. Methods The junior students (n=307)of clinical medicine were selected as research subjects by random cluster sampling. They were divided into the teaching improving group (n=151) who accepted case teaching and control group (n=156)who accepted traditional teaching. At the end of the term,the teaching effect was surveyed by questionnaires and compared between the two groups. Measurement data was analyzed by t test,enumeration data by χ2 test and ranked data by rank sum test. Results Students' interests of medical statistics and understanding the importance of the course in teaching improving group were significantly higher than that in control group (Z=-2.375,P=0.018;Z=-2.971,P=0.003). The proportion of students with learning difficulties in teaching improving group was obviously lower than that in control group (Z=-2.488,P=0.013). The satisfaction with theory and practical teaching in teaching improving group (84.10% and 88.74%,respectively)was significantly higher that in control group (73.08%and 71.79%,respectively)(χ2=5.530,P=0.013;χ2=13.841,P<0.001). Although no difference was observed in the test score between the two groups (t=1.230,P=0.220),knowledge of parameter estimation,hypothesis testing and science research design in teach-ing improving group was significantly higher than that in control group (χ2=6.829,P=0.009;χ2=5.835, P=0.016). Conclusions Application of ‘incorrect cases’in medical statistics teaching could arouse students' learning interests and improve clinical medical students' comprehensive analy sis ability of medical statistics.

Objective To investigate the effects of sequential pulmonary resuscitation maneuver (RM) with pulmonary protective ventilation on hemodynamics and arterial blood gas in patients with acute respiratory distress syndrome (ARDS) caused by severe chest trauma. Methods Ninety-six ARDS patients caused by severe chest trauma admitted to Dongguan People's Hospital from January 2017 to December 2018 were enrolled, and they were divided into a RM group and a mechanical ventilation group according to different ventilation modes, 48 cases being in each group. The mechanical ventilation group was given low tidal volume ventilation combined with the best positive end-expiratory pressure (PEEP); while the RM group was given sequential lung RM therapy on the basis of treatment in the mechanical ventilation group. The heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), cardiac output (CO), cardiac output index (CI), systemic circulation resistance index (SVRI) arterial blood gas were monitored before and after treatment in the two groups, and oxygenation index(PaO2/FiO2) was calculated; The mechanical ventilation time, intensive care unit (ICU) hospitalization time, incidence of ventilator associated pneumonia (VAP), mortality and incidence of adverse reaction were observed between the two groups. Results After treatment, the pH value and arterial partial pressure of carbon dioxide (PaCO2) of the two groups had no significant change; with the prolongation of treatment, the arterial partial pressure of oxygen (PaO2) and arterial blood oxygen saturation (SaO2);PaO2/FiO2 were increased significantly, total carbon dioxide (TCO2) was decreased significantly, after 72 hours of treatment, the degree of change in the RM group were more remarkable greater than those in the mechanical ventilation group [PaO2 (mmHg, 1 mmHg = 0.133 kPa): 91.02±9.03 vs. 80.34±7.66, SaO2: 0.96±0.04 vs. 0.94±0.04, TCO2 (mmol/L): 24.72±2.83 vs. 23.54±2.76, PaO2/FiO2 (mmHg): 238.47±19.83 vs. 185.34±17.37, all P < 0.05]. The ICU hospitalization time and mechanical ventilation time in the RM group were significantly lower than those in the mechanical ventilation group [ICU hospitalization time (days): 22.03±3.39 vs. 26.75±4.04,mechanical ventilation time (days): 13.38±4.04 vs. 19.33±5.02], and the incidence of VAP and mortality in the RM group were significantly lower than those in the mechanical ventilation group[incidence of VAP: 25.00% (12/48) vs. 8.33% (4/48), mortality: 18.75% (9/48) vs. 22.92% (11/48), both P < 0.05]. With the extension of time, CVP, MAP, CO, CI and SVRI in RM group all showed a trend of first decreasing and then increasing, while HR showed a trend of increasing and then decreasing, and the above indicators in 5 minutes after pulmonary re-opening, gradually returned to normal, showing no statistical significances compared with those before treatment [HR (bpm): 97.88±6.22 vs. 98.20±8.37, CVP (mmHg): 6.33±1.35 vs. 6.32±1.36, MAP (mmHg): 94.56±5.96 vs. 95.03±9.82, CO (L/min): 6.34±1.42 vs. 6.40±1.23, CI (L·min-1·s-1):2.08±0.32 vs. 2.17±0.53, SVRI: 2 404.34±31.34 vs. 2 474.34±29.73, all P > 0.05]. No adverse reactions occurred in the two groups. Conclusion Pulmonary protective ventilation sequential lung recruitment maneuver can significantly improve the oxygenation of ARDS caused by severe chest trauma, shorten the durations of mechanical ventilation and hospitalization in ICU, reduce the incidence of VAP, improve pulmonary inflammation, and in the mean time it has no serious adverse effects on hemodynamics.

Objective:To evaluate the effect of melatonin on prefrontal cortex ischemia-induced cognitive impairment in rats and to investigate the receptor mechanism.Methods:Clean-grade adult male Sprague-Dawley rats, weighing 300 g, were selected, and a catheter was implanted into the prefrontal cortex.The experiment was performed in two parts.Experiment Ⅰ Twenty-four rats, in which catheters were successfully inserted into the prefrontal cortex, were assigned into 3 groups ( n=8 each) using a random number table method: control group (group C), model group (group M) and melatonin group (group ME). Normal saline 0.5 μl was injected into the prefrontal cortex in group C, 1 μmol/L endothelin 0.5 μl was microinjected into the prefrontal cortex in group M, and 1 μmol/L endothelin and 1 μmol/L melatonin 0.5 μl were injected into the prefrontal cortex in group ME.Experiment Ⅱ Forty-four rats, in which catheters were successfully inserted into the prefrontal cortex, were assigned into 4 groups ( n=11 each) using a random number table method: model group (group M), melatonin group (group ME), MT 1/2R antagonist luzindole + melatonin group (group L + ME) and MT 2R antagonist 4p-pdot + melatonin group (group P + ME). In group M, 1 μmol/l endothelin 0.5 μl was microinjected into the prefrontal cortex.In group ME, 1 μmol/L endothelin + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.In group L + ME, 1 μmol/L endothelin + 1 μmol/L MT 1/2R antagonist + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.In group P + ME, 1 μmol/L endothelin + 1 μmol/L MT 2R antagonist + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.T-maze and the open field tests were performed at 1 week after administration. Results:Experiment Ⅰ There was no significant difference in the locomotor speed in open field test among C, M and ME groups ( P>0.05). The rate of correct selection in T-maze test was significantly lower in M and ME groups than in group C and higher in group ME than in group M( P<0.05). Experiment Ⅱ There was no significant difference in the locomotor speed in open field test among the four groups( P>0.05). Compared with group M, the rate of correct selection in open field test was significantly increased in ME and P+ ME groups ( P<0.05), and no significant change was found in group L+ ME ( P>0.05). Compared with group ME, the rate of correct selection in open field test was significantly decreased in group L+ ME ( P<0.05), and no significant change was found in group P+ ME( P>0.05). Conclusion:Melatonin can attenuate prefrontal cortex ischemia-induced cognitive impairment in the rats, and the mechanism is related to activation of MT 1R.

Objective: To explore the correlation between blood pressure and urinary phthalandione, MMP, MEP, MnBP, MiBP, PAEs. Methods: Three schools were selected from Shenzhen, China for the present study. A total of 765 firstgrade students of Han ethnicity were recruited voluntarily from the selected schools during September 2016 to June 2017. They were divided into normal blood pressure (BP) group (lower than P90 group) and high BP group (BP≥P90). Linear and Logistic regression models were used to analyze the relationships between blood pressure and urine phthalate metabolite levels. Results: Urinary MMP and MnBP in students of high BP group were significantly higher than that of students in normal BP group(t=13.12, 3.97, P<0.05). Linear regression models showed that Z score increased when MMP and MnBP levels increased(P<0.05). Logistic regression model suggested that the risk of high BP increased with the increment of MMP level adjusting creatinine, sex, age and BMI(OR=1.47, P<0.05). There was no statistical significance in the differences after adjusting many factors including family income and education level of parents(P>0.05). Conclusion Urinary phthalate metabolite levels are positively associated with blood pressure in first-grade children.

Objective    To analyze the occurrence of postoperative pulmonary complications (PPC) and the risk factors in patients with spontaneous pneumothorax who underwent micro single-port video-assisted thoracoscopic surgery (VATS). Methods    A total of 158 patients with spontaneous pneumothorax who underwent micro single-port VATS in our hospital from April 2017 to December 2019 were retrospectively included, including 99 males and 59 females, with an average age of 40.53±9.97 years. The patients were divided into a PPC group (n=21) and a non-PPC group (n=137) according to whether PPC occurred after the operation, and the risk factors for the occurrence of PPC were analyzed. Results    All 158 patients successfully completed the micro single-port VATS, and there was no intraoperative death. The postoperative chest tightness, chest pain, and dyspnea symptoms basically disappeared. During the postoperative period, there were 3 patients of pulmonary infection, 7 patients of atelectasis, 4 patients of pulmonary leak, 6 patients of pleural effusion, 1 patient of atelectasis and pleural effusion, and the incidence of PPC was 13.29% (21/158). Multivariate logistic regression analysis showed that lung disease [OR=32.404, 95%CI (2.717, 386.452), P=0.006], preoperative albumin level≤35 g/L [OR=14.912, 95%CI (1.719, 129.353), P=0.014], severe pleural adhesions [OR=26.023, 95%CI (3.294, 205.557), P=0.002], pain grade Ⅱ-Ⅲ 24 hours after the surgery [OR=64.024, 95%CI (3.606, 1 136.677), P=0.005] , age [OR=1.195, 95%CI (1.065, 1.342), P=0.002], intraoperative blood loss [OR=1.087, 95%CI (1.018, 1.162), P=0.013] were the risk factors for PPC after micro single-port VATS. Conclusion    There is a close relationship between PPC after micro single-port VATS and perioperative indexes in patients with spontaneous pneumothorax. Clinically, targeted prevention and treatment can be implemented according to the age, pulmonary disease, preoperative albumin level, intraoperative blood loss, degree of pleural adhesion and pain grading 24 hours after surgery.

Objective:This study aims to explore the impact of various clinical factors on the risk of polymyxin B induced DKI in patients.Methods:This is a single-center retrospective case-control study. A total of 139 patients receiving polymyxin B intravenous treatment in our hospital from January 1 to December 31, 2020 were collected. Baseline variables between polymyxin B induced DKI group and non-DKI group were compared using the Chi-square test or Fisher's exact test for categorical variables and the T-test or Wilcoxon rank sum test for continuous variables, as appropriate. Statistical analysis was performed using univariate and multivariate Logistic regression models, Logistic regression models, multivariate Logistic regression models, Kaplan Meier curve, as well as Log-Rank test.Results:Among a total of 139 patients receiving polymyxin B treatment, 49 cases have experienced DKI, 90 cases did not. The incidence of DKI was 35.25%. There was no statistical difference in general information of age, gender, and proportion of standard weight between the two groups. Among the related indexes of polycolistin B administration, the proportion of high daily dose [>25 000 U/(kg·d)] and the total dosage of medication in the DKI group were both significantly higher than that in the non-DKI group ( P< 0.05, respectively). Among the organ function indexes, there were significant differences in initial serum creatinine, blood urea nitrogen, uric acid, urinary occult blood and urinary specific gravity between DKI group and non-DKI group 48 hours before polymyxin B administration ( P< 0.05). Binary Logistic regression analysis suggested that daily dose and initial creatinine before medication were independent risk factors for DKI caused by polymyxin B ( P< 0.05). Kaplan-meier survival analysis showed that with the accumulation of Polymyxin B administration, the higher the daily dose of Polymyxin B was, the faster the DKI occurred (Log-Rank P= 0.0194). Conclusions:Using intravenous polymyxin B is associated with the risk of DKI, among which higher initial blood creatinine values and higher daily doses are independent risk factors for DKI.

OBJECTIVETo investigate the potential substitution effect of hOGG1 and hMTH1 on oxidative DNA damage, based on gene-deficient cell strains models.

METHODShOGG1 and hMTH1 gene deficient cell strains models were established by Human embryonic lung fibroblasts (HFL) cells. After HFL cells being exposed to 100 µmol/L H₂O₂ for 12 h, HPLC-EC detecting technique and RT-PCR method were adopted to analyze the genetic expression level of 8-oxo-dG (7, 8-dihydro-8-oxoguanine).

RESULTSThe gene-deficient cell strains models of hOGG1 and hMTH1 were obtained by infecting target cells with high titer of lentivirus. The mRNA expression level of hOGG1 was 0.09 ± 0.02, 91% lower than it in normal HFL cells, which was 1.00 ± 0.04. As the same, the mRNA expression level of hMTH1 (0.41 ± 0.04) also decreased by 60% compared with it in normal HFL cells (1.02 ± 0.06). After induced by 100 µmol/L H₂O₂ for 12 h, the genetic expression level of hMTH1 in hOGG1 gene-deficient cells (1.26 ± 0.18) increased 25% compared with it in control group (1.01 ± 0.07). Meanwhile, the genetic expression level of hOGG1 in hMTH1 gene-deficient cells (1.54 ± 0.25) also increased by 52%. The DNA 8-oxo-dG levels in hOGG1 gene-deficient cells (2.48 ± 0.54) was 3.1 times compared with it in the control group (0.80 ± 0.16), the difference showed statistical significance (P < 0.01). Whereas the 8-oxo-dG levels in hMTH1 gene-deficient cells (1.84 ± 0.46) was 2.3 times of it in the control group, the difference also showed statistical significance (P < 0.01).

CONCLUSIONBased on gene-deficient HFL cells models, a synergetic substitution effect on DNA damage and repair activity by both hOGG1 and hMTH1 were firstly discovered when induced by oxidation. The substitution effect of hOGG1 were stronger than that of hMTH1.

Cell Line ; DNA Damage ; DNA Glycosylases ; genetics ; DNA Repair ; DNA Repair Enzymes ; genetics ; Fibroblasts ; metabolism ; Humans ; Oxidative Stress ; genetics ; Phosphoric Monoester Hydrolases ; genetics