[The role of preventive pancreatic duct stent placement in preventing acute pancreatitis after endoscopic retrograde cholangiopancreatography]

The aim of this study was to investigate the preventive effect of pancreatic duct stent on acute pancreatitis after endoscopic retrograde cholangiopancreatography. A retrospective analysis of the case data of patients who first underwent endoscopic retrograde cholangiopancreatography for choledocholithiasis in the Beijing Friendship Hospital from January 2015 to December 2019 for 5 years. According to whether the pancreatic duct stent was indwelled during the operation, they were divided into pancreatic duct stent group (147 cases) and non-indwelling pancreatic duct stent group (192 cases). The incidence of acute pancreatitis after endoscopic retrograde cholangiopancreatography was compared between the two groups according to COTTON criteria. Independent sample t test, Pearson Chi-square test (χ²) and Fisher's exact test were used to compare groups' differences. There were 2 cases of acute pancreatitis in the pancreatic duct stent group, all of which improved after 48 hours. There were 22 cases of acute pancreatitis in the non-indwelling pancreatic duct stent group, of which 20 cases improved within 48 hours, and the other 2 cases had severe pancreatitis, which improved and discharged after 30 days of treatment. There was significant difference in the incidence of acute pancreatitis between the pancreatic duct stenting group (1.4%) and the group without placement of pancreatic duct stents (11.5%) (χ²=12.905,P<0.001). In conclusion, Pancreatic duct stent may be an effective method to prevent PEP.

[The value of myocardial work in detecting the reduction of left ventricular global systolic function in acute myocardial infarction patients with preserved ejection fraction]

Objective: To investigate the diagnosis value of myocardial work (MW) in evaluating left ventricular global systolic function among acute myocardial infarction (AMI) patients with preserved ejection fraction (LVEF). Methods: This study was a diagnostic trial in a prospective case-control design. AMI patients with preserved LVEF were enrolled as AMI(LVEF>50%) group and age and sex-matched healthy individuals undergoing healthy checkup in our hospital were collected as control group. Two-dimensional dynamic images, including standard apical two-chamber, long-axis and four-chamber views in 3 consecutive cardiac cycles were acquired. General clinical data, routine echocardiography and myocardial work parameters were obtained from all subjects. The indices were compared between the two groups. Intra-observer and inter-observer repeatability of myocardial work parameters were evaluated by intra-group correlation coefficient (ICC). Receiver operator characteristic (ROC) curve was used to determine the diagnostic value of global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE) and global work index (GWI) on the reduction of left ventricular global systolic function in AMI(LVEF>50%) group. Results: There were 30 patients in AMI(LVEF>50%) group, the age was (67.3±9.7)years, and 14 cases were female(46.7%). Thirty participants were included in the control group, the age was (68.1±8.6)years, and 12 cases were female (40.0%). Compared with the control group, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), interventricular septum thickness (IVSD), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), peak early diastolic velocity of mitral orifice/tissue Doppler velocity of posterior mitral annulus (E/e), left ventricular mass (LVM), left ventricular mass index (LVMI) were significantly higher, while E and e values were significantly lower in AMI (LVEF>50%) group (all P<0.05). Compared with the control group, GCW ((1 145.9±440.1)mmHg% (1 mmHg=0.133 kPa) vs. (1 425.7±355.4)mmHg%), GWE ((80.9±9.5)% vs. (87.3±5.5)%), GWI ((1 001.3±416.2)mmHg% vs. (1 247.6±341.7)mmHg%) and the absolute value of long axis integral strain (GLS) ((8.5±3.4)% vs. (11.4±3.7)%) were significantly lower, while peak strain dispersion(PSD)((101.3±66.4)ms vs. (74.7±31.9)ms) was significantly higher in AMI(LVEF>50%) group (P all<0 05). There was no significant difference in GWW((177.2±71.1)mmHg% vs. (155.7±64.6)mmHg%) between the two groups (P>0.05). The reproducibility of GCW, GWW, GWE and GWI within and between observers were satisfactory (all ICC>0.75). ROC curve analysis showed that all four parameters, GCW, GWW, GWE, and GWI, could be used for the diagnosis of reduced left ventricular systolic function in patients with AMI (LVEF>50%), and their areas under the ROC curve were 0.896,0.929,0.808,0.862. Conclusion: Myocardial work assessment is valuable on diagnosing left ventricular global systolic function reduction in AMI patients with preserved LVEF.

[Meteorological factors and related lag effects on scrub typhus in southwestern Yunnan]

Objective: To analyze the influence and related lag effects of meteorological factors on scrub typhus (ST) in southwestern Yunnan, to provide a reference for the corresponding prevention and treatment measures. Methods: Data on ST and meteorology in Yunnan province from 2007 to 2018 were collected. A distributed lag nonlinear model was conducted to study the cumulative lag effects of temperature, relative humidity, and rainfall on ST. Results: From 2007-2018, a total of 19 975 ST cases were reported in southwestern Yunnan. Weekly mean temperature, mean relative humidity, and the risk of ST all showed J-shaped curves. The cumulative risk of ST increased with mean temperature >23 ℃, mean relative humidity >80%, and cumulative rainfall between 20 and 60 mm or over 100 mm, weekly. Taking the median value as the reference, higher temperature (22.27 ℃, 23.45 ℃), relative humidity (80.14%, 84.38%) and rainfall (37.17 mm, 74.42 mm) all increased the risk of disease while lower temperature (11.22 ℃,14.83 ℃), relative humidity (53.18%,65.36%) and rainfall (0.00 mm,0.55 mm) showed opposite effects. The temperature-lag effect lasted for 10 and 16 weeks, respectively, with ST's risk the highest during the week of exposure. Humidity-lag effects usually last for 10 and 17 weeks. The lag effect of rainfall lasted for 25 weeks, while the disease's risk was the highest in the 4^th week. Conclusion: Factors as temperature, relative humidity, and precipitation showed nonlinear and lag effects on ST. High temperature, high relative humidity, and an appropriate amount of rainfalls increase the risk of ST. The authorities of public health should implement effective prevention and control measures according to meteorological conditions.

[Association between fatty liver and type 2 diabetes in the baseline population of Jinchang Cohort]

Objective: To explore the association between fatty liver and type 2 diabetes mellitus (T2DM) in the baseline-population of Jinchang cohort study. Methods: Data from all the participants involved in the baseline-population of Jinchang cohort study was used, to compare the risks of T2DM in fatty liver and non fatty liver groups and to explore the interaction between family history or fatty liver of diabetes and the prevalence of T2DM. Results: Among all the 46 861 participants, 10 574 were diagnosed as having fatty liver (22.56%), with the standardized rate as 20.66%. Another 3 818 participants were diagnosed as having T2DM (8.15%) with standardized rate as 6.90%. The prevalence of T2DM increased in parallel with the increase of age (trend χ(2)=2 833.671, trend P<0.001). The prevalence of T2DM in the fatty liver group was significantly higher than that in the non-fatty liver group, both in men or women and in the overall population. Compared with the group of non-fatty liver, the risks of T2DM in fatty liver group were seen 1.78 times higher in males, 2.33 times in women and 2.10 times in the overall population, after adjustment for factors as age, levels of education, smoking, drinking, physical exercise, BMI, family history of diabetes and some metabolic indicators (pressure, TC, TG, uric acid, ALT, AST, gamma-glutamyl transferase). Date from the interaction model showed that fatty liver and family history of diabetes present a positive additive interaction on T2DM (RERI=1.18, 95%CI: 0.59-1.78; AP=0.24, 95%CI: 0.14-0.34; S=1.43, 95%CI: 1.21-1.69). Conclusions: Fatty liver could significantly increase the risk of T2DM and a positive additive interaction was also observed between fatty liver and family history of diabetes on T2DM. It was important to strengthen the prevention program on T2DM, in order to effectively control the development of fatty liver.

Genetic diversity and the conservation priority of Glycine soja populations from Northern China

Knowledge of the spatial patterns of genetic variation in wild populations has significant implications for in situ conservation and the determination of conservation order. To study the levels of genetic diversity, spatial genetic structures, and genetic distances in Glycine soja, 11 natural populations in northern China were analyzed by estimating genetic coefficients using inter-simple sequence repeat (ISSR) fingerprints via mixed sampling strategies. Sixteen ISSR primers generated 98 reproducible polymorphic amplification banding patterns of 172 scored, accounting for 56.98% of the polymorphisms among the populations. The dendrogram based on Nei's genetic distance showed that distinct genetic differentiation occurred in G. soja. The Unweighted Pair-Group Method with Arithmetic Mean cluster analysis indicated two broad groups, and one contained all of the populations except three from Chengde, which formed the smaller second group. The spatial genetic structure evident in the wild soybean populations may be attributed to restricted seed dispersal and the dominant breeding system of this species. The detection of genetic structures in wild soybean populations could be a significant index for the effective conservation of many wild populations, and it could be exploited by soybean breeding programs to increase production.

Quantum-mechanical approach to predissociation of water dimers in the vibrational adiabatic representation: Importance of channel interactions

The results of application of the quantum-mechanical adiabatic theory to vibrational predissociation (VPD) of water dimers, (H2O)2 and (D2O)2, are presented. We consider the VPD processes including the totally symmetric OH mode of the dimer and the bending mode of the fragment. The VPD in the adiabatic representation is induced by breakdown of the vibrational adiabatic approximation, and two types of nonadiabatic coupling matrix elements are involved: one provides the VPD induced by the low-frequency dissociation mode and the other provides the VPD through channel interactions induced by the low-frequency modes. The VPD rate constants were calculated using the Fermi golden rule expression. A closed form for the nonadiabatic transition matrix element between the discrete and continuum states was derived in the Morse potential model. All of the parameters used were obtained from the potential surfaces of the water dimers, which were calculated by the density functional theory procedures. The VPD rate constants for the two processes were calculated in the non-Condon scheme beyond the so-called Condon approximation. The channel interactions in and between the initial and final states were taken into account, and those are found to increase the VPD rates by 3(1) orders of magnitude for the VPD processes in (H2O)2 ((D2O)2). The fraction of the bending-excited donor fragments is larger than that of the bending-excited acceptor fragments. The results obtained by quantum-mechanical approach are compared with both experimental and quasi-classical trajectory calculation results.

Series of new β-cyclodextrin-cored starlike carriers for gene delivery

The development of safe and effective β-cyclodextrin (β-CD)-cored cationic star gene carriers has attracted considerable attention. In this work, a series of star-shaped hemocompatible CD-PGPP, CD-PGAEPP, and CD-PGAPP vectors composed of β-CD cores and piperazine (PP)-, N-(aminoethyl)piperazine (AEPP)-, or N-(3-aminopropyl)-2-pyrrolidinone (APP)-functionalized poly(glycidyl methacrylate) arms were successfully proposed and compared for highly efficient gene delivery. Such star carriers possess plentiful secondary amine, tertiary amine, and nonionic hydroxyl groups. CD-PGPP, CD-PGAEPP, and CD-PGAPP were effective in condensing plasmid DNA into nanoparticles, whose sizes were 100-200 nm and positive ζ potentials were 25-40 mV at nitrogen/phosphate (N/P) ratios of 10 and above. CD-PGPP, CD-PGAEPP, and CD-PGAPP showed significantly lower cytotoxicity than control poly(ethylenimine) (PEI; ∼25 kDa). At most N/P ratios, CD-PGAPP exhibited better gene transfection performance than CD-PGPP and CD-PGAEPP particularly in HepG2 cells. More importantly, in comparison with PEI, all of the CD-PGPP, CD-PGAEPP, and CD-PGAPP vectors did not cause undesirable hemolysis.

Cryopreservation of in vitro grown shoot tips of Diospyros kaki thunb. using different methods

The objective of this study was to compare the potential of different cryopreservation strategies for in vitro shoot tips of Diospyros kaki Thunb. The treatments consisted of three different cryopreservation methods: vitrification, droplet-vitrification and modified droplet-vitrification. The following variables were assessed: cold acclimation, sucrose concentration in the preculture medium and PVS2 treatment time. A higher average survival level was obtained using the modified droplet-vitrification method compared to the other two methods.

[Analyses of chromosomal karyotypes and cytogenetic variations of animal cell lines]

After the master cell stock(mcs) and working cell bank of more than 30 different strains of 7 animal kidney cell lines (F-81 or CRFK cell line, MDCK cell line, Vero or Vero-2 cell line, MA-104 cell line and BHK-21 cell line) were established in China, the chromosomal number variations and structural aberrations of the above lines, primary feline or canine kidney cell (FKC or CKC) and HeLa cell line were investigated and their karyotypes of routine or Giemsa chromosomal bands were analyzed. The carcinogenesis or tumorigenicity testing of these cells in about 700 nude mice and for colony formation in soft agar (SA) and for agglutination under different concentration of plant lectins was carried out. Both tumorigenicity-negative strains of F-81, CRFK, Vero or Vero-2 lines and very-low-tumorigenicity strains of MDCK line were successfully selected and evaluated for the production of canine or feline combination viral vaccines, which are free of infectious agents, and described with respect to cytogenetic characteristics and tumorigenicity. Rate of modal chromosome number represents the ratio of cell number having modal chromosome number to all the split cell number analyzed at random. Rate of difference represents the ratio of difference of the rate of modal chromosome number between mcs (master cell stock) + n and mcs passages. The chromosomal analysis results showed that the ratio of difference of the rate of modal chromosome number between mcs + n and mcs passages was not more than 5%-15% and the structure aberrations was generally 0%-3%, not more than 5%-10%, thus the hereditary character of cell lines is comparatively stable without significant difference between different passages. The genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species specific. Experimental models were established for the researches on the prevention and prophylaxis of malignant tumors or cancers and their genetically biological characteristics. Tests showed that there was correlation among cell line chromosome number variations, anchorage independence in soft agar, agglutination under plant lectins and tumor-forming ability in nude mice. Since testing in vitro is more economic, simpler, faster, and is thought to be reliable, we recommend plant lectins followed by SA or analysis of karyotypes as the initial means for monitoring tumorigenicity of animal cell line in nude mice.

The diagnostic value of transendoscopic miniature ultrasonic probe for esophageal diseases

BACKGROUND AND STUDY AIMS

To investigate the value of a transendoscopic miniature ultrasonic probe (USP) in the diagnosis of esophageal diseases.

PATIENTS AND METHODS

Endoscopic ultrasonography was performed by means of USP in 53 patients with esophageal diseases, including 16 with esophageal leiomyoma, 14 with esophageal carcinoma, seven with achalasia, seven with reflux esophagitis, six with esophageal polyps and three with esophageal varices.

RESULTS

USP clearly showed all 16 esophageal leiomyomas, whereas, conventional EUS could not show five small leiomyomas less than 1.0 x 1.0 cm in size. The appearance of esophageal leiomyoma was that of a hypoechoic mass with a homogeneous inner echogram arising from the fourth hypoechoic layer. All 14 patients with esophageal carcinoma underwent full endosonographic T and N staging with USP. In two cases passage of the malignant stenosis proved to be impossible using conventional EUS. The accuracy of USP on T staging and N staging was 80% and 30%, respectively. In the seven achalasia patients USP demonstrated a seven-layer structure of the esophageal wall, with thickening of the third and fifth layers. In the seven patients with reflux esophagitis no difference was found for the ultrasonic image between that with and that without Barrett's epithelium. All of the esophageal polyps were showed by USP as hypoechoic homogeneous lesion with indistinct margins. After endoscopic sclerotherapy the ultrasonographic feature of esophageal varices changed from submucosal multiple anechoic areas to high echoic areas.

CONCLUSION

With refinement, the transendoscopic miniature ultrasonic probe will play an increasing role in the diagnosis of esophageal disease.

The roles of reactive oxygen species and endogenous opioid peptides in ischemia-induced arrhythmia of isolated rat hearts

Although the formation of oxygen-derived free radicals (or reactive oxygen species; ROS) and the release of endogenous opioid peptides (EOP) have been independently reported to be the major arrhythmogenic factors in ischemic hearts, possible relations between these two factors have seldom been investigated. Thus, we studied whether the ROS and EOP were related in the progression of ischemia-induced arrhythmias. Isolated rat hearts perfused in the Langendorff mode were treated with dynorphin A1-13 (kappa EOP receptor agonist), and/or allopurinol (xanthine oxidase inhibitor), before the onset of ischemia induced by ligating the left coronary arteries. Ischemic period lasted for 30 min, during which cardiac rhythms were recorded. At the end of ischemia, hearts were analyzed for the glutathione and ascorbate levels. Allopurinol (100 nmoles/heart) was effective in reducing the severity of arrhythmia (arrhythmia score: Mean +/- SEM 3.00 +/- 0.80 for allopurinol, 5.75 +/- 0.41 for placebo, p < 0.01), while dynorphin (10 micrograms/heart) potentiated the arrhythmia (6.71 +/- 0.52, p < 0.05 vs. placebo). Coadministration of allopurinol and dynorphin was capable of reducing arrhythmia (5.57 +/- 0.65) when compared with the administration of dynorphin alone (6.71 +/- 0.52, p < 0.05). Tissue oxidative stress was evaluated by the concentrations of glutathione (GSH) and ascorbate. Allopurinol did not significantly elevate tissue GSH concentrations (1.46 +/- 0.05 mumoles/g wet wt) in ischemic hearts, while dynorphin alone significantly decreased the GSH concentrations (0.96 +/- 0.08, p < 0.05) when compared with the placebo (1.32 +/- 0.03). The dynorphin-induced GSH decrease cannot be reversed by coadministration with allopurinol (0.90 +/- 0.104). Allopurinol significantly elevated tissue ascorbate levels (0.16 +/- 0.01) when compared with placebo (0.10 +/- 0.01, p < 0.05). Interestingly, dynorphin alone also elevated the tissue ascorbate concentrations (0.16 +/- 0.02). Coadministration of allopurinol and dynorphin further spiked the ascorbate levels (0.28 +/- 0.05, p < 0.01). In conclusion, the results suggested that ischemia-induced arrhythmia mechanisms might involve the formation of superoxide and other ROS, which were probably generated from the release of EOP (or EOP/EOP receptor interactions). Superoxide, the formation of which can be inhibited by allopurinol that exerted antiarrhythmic effect, was probably scavenged by ascorbate in myocardial ischemia. The ROS resulting from EOP/EOP receptor interactions were probably scavenged by glutathione system. Elevated ascorbate levels in dynorphin-treated hearts might result from the compensatory synthesis induced by decreased glutathione levels.