This paper validated the centrode of six-bar mechanism was similar to circle center curve for different bending radius of the lemur, and introduced the gait analysis of knee joint of six-bar mechanism in normal movement t oprovide theoretical design foundation for developing a new knee joint.

Objective To investigate the effects of astragalus injection on the morphology and expression of Apaf-1 in hippocampal neurons after cerebral ischemia reperfusion in rats. Methods The male SD rats were randomly divided into 3 groups, sham-operated group, cerebral ischemia-reperfusion group (reperfusion group) and astragalus injection interven-tion group (experiment group). The global cerebral ischemia-reperfusion rat model was established by Pulsinelli four-vessel occlusion method. The astragalus injection group was intraperitoneally injected with astragalus 6 mL/kg, 30 mins before sur-gery and repeated every 24 h. Rat brains were removed 24 h after reperfusion in each group. HE staining was used to observe the pathological changes of the hippocampal neurons under the light microscope. The ultrastructural changes of hippocam-pal neurons were observed by transmission electron microscopy. Immunohistochemistry and Western blot methods were used to measure the expression of apoptotic protease activating factor-1(Apaf-1) protein. Results Compared with sham-operat-ed group, nuclear and mitochondrial damage was found in reperfusion group, and the expression of Apaf-1 protein increased obviously in hippocampus(Immunohistochemistry result:0.024 ± 0.001 vs 0.109 ± 0.011;Western blot result:0.270 ± 0.018 vs 0.894±0.072, P<0.01). Compared with reperfusion group, the damage in nuclear and mitochondria was relieved obviously in experiment group, and the expression of Apaf-1 protein in hippocampus was significantly decreased (Immunohistochemistry result:0.048±0.005;Western blot result:0.392±0.046, P<0.01). Conclusion Astragalus injection can reduce pathological damage of hippocampal neurons after cerebral ischemia and reperfusion in rats, and the mechanism is related with inhibiting of Apaf-1 protein.

Objective To investigate the effect of Arsenic Trioxide(As_2O_3) combined with radiation on the apoptosis of nasopharyngeal carcinoma cells in vitro.Methods Using MTT and FCM to detect the cytotoxic and apoptosis at different As_2O_3 concentrations combined with 2Gy radiation on nasopharyngeal carcinoma cells(CNE1).Results Inhibition of cell proliferation seemed more dependent on the increase of As_2O_3 concentration.Cell survival rate was lower in the combination of As_2O_3 and radiation group than As_2O_3 alone.Conclusion As_2O_3 can enhance radiation effect obviously in nasopharyngeal carcinoma cells,especially at lower radiation dose.

Objective To investigate the effect of pathophysiology case-based learning(CBL)method on scores of pediatrics.Methods Undergraduates from 2005 grade at Chengde medical college were divided into two groups:experimental group(n=138,CBL method)and control group(n=136,conventional teaching method).The scores of pediatrics between the two groups were compared.The pediatrics test paper was divided into two types:type B,which was tightly connected with the pathophysiology knowledge and type F,which had less connection with pathophysiology knowledge.The accuracy rates of both groups were compared.Correlation analysis on scores between pathophysiology and internal medicine,surgery,pediatrics,obstetircs and gynaecology was made.Results No significant difference in total scores of pediatrics was observed between the two groups(P＞0.05);total accuracy rate of experimental group was higher than that of control group(P＞0.05);similar total accuracy rates of type F test paper were observed in both groups(P＞0.05);positive correlations in scores between pathophysiology and internal medicine,surgery,pediatrics,obstetircs and gynaecology were found.Conclusions Satisfactory long-term effect are received by applying pathophysiological CBL model since it can promote the application of pathophysiological knowledge in pediatrics,however,no apparent effect on students'clinical ability can be obtained from the mere application of CBL in pathophysiology course.

Objective To compare the effects of different extracts of Rheum palmatum on weight and tissue structure of hypothalamusand and pituitary of adult female rats,and screen the main reproductive toxicity extract.Methods The water,chloroform,ethyl acetate,and n-butanol extracts and water-soluble substance of R.palmatum were prepared by polarity gradient extraction method.Female adult rats were randomly divided into blank control group,rhubarb water extract group,and different extracts groups.The dosage of all the groups was equivalent to 4.00 g/kg crude rhubarb.Rats were administered with extracts by gavage for 60 d.Body mass growth rate of rats were calculated before and after administration.The pathological changes of hypothalamic arcuate nucleus neurons and pituitary gonadal cell were observed with light microscope.Results Compared with the blank control group,the body mass growth rate of rhubarb water extract group was decreased (P ＜ 0.05),while those in the different extracts groups were increased (P ＜ 0.01);The hypothalamic arcuate nucleus neurons of rhubarb water extract group showed chromatin marginalization,nissl substance dissolving,fuzzy boundary of nuclear membrane,as well as hell cells,and the total number of adenohypophysis cells reduced and the cells arranged in irregular.However,there were no apparent pathologic changes in different extracts groups.Conclusion Rhubarb water extract administration by long-term dose can reduce weight growth rate and result in pathologic changes of hypothalamic arcuate nucleus and adenohypophysis,while the different extracts can increase weight growth rate significantly and have little effects on the organizational structure ofhypothalamic arcuate nucleus and adenohypophysis.

BACKGROUND:The studies have shown that the mesenchymal stem cel s derived from bone marrow and umbilical cord can be continuously cultured in vitro, and maintain the characteristics of stem cel s. The mesenchymal stem cel s can differentiate into hepatocyte-like cel s after“cocktail”induction by various cytokines. OBJECTIVE:To further identify whether umbilical cord-derived mesenchymal stem cel s in vitro co-cultured with normal hepatocytes can differentiate into hepatocyte-like cel s, and to investigate the differentiation method. METHODS:Mesenchymal stem cel s were isolated from human umbilical cord with adherent method, and the surface markers of umbilical cord-derived mesenchymal stem cel s were detected with flow cytometry. The umbilical cord-derived mesenchymal stem cel s were co-cultured with liver LO2 cel s without adding exogenous inducers. The expressions of alpha-fetoprotein, albumin and human cytokeratin 19 mRNA of hepatocyte specific markers were detected with reverse transcription PCR at 7, 14 and 21 days after culture, and periodic acid-Schiff staining was used to identify the functions. RESULTS AND CONCLUSION:Mesenchymal stem cel s could isolated from human umbilical cord successful y, showing fibroblastic morphology and adherent cel characterization. Among these cel s, 96.02%cel s were CD29 positive cel s and 96.6%cel s were CD105 positive cel s. The percentage of CD34 negative cel s was 99.65%. The percentage of CD105+CD29+double positive cel s was 94.84%. The mRNA of alpha-fetoprotein was found on the 7th day after co-cultured with LO2 cel s, and the mRNA of albumin and human cytokeratin 19 were found on the 14th day. After co-cultured for 21 days, the alpha-fetoprotein mRNA could not be observed in the co-culture group. The expressions of albumin and human cytokeratin 19 were increased at 14 days. After co-cultured for 21 days, the glycogen staining was positive. Umbilical cord-derived mesenchymal stem cel s can differentiate into hepatocyte-like cel s after co-cultured with normal hepatocytes.

Objective: To prepare a composite membrane by chitosan/β-sodium glycerophosphate(CS/β-GP) thermosensitive hydrogel combined with stromal cell derived factor-1(SDF-1) and observe its biological characteristics in vitro. Methods: Different doses of SDF-1 were added into CS/β-GP solution and then the thermosensitive gel time was measured. The SDF-1/CS/β-GP solution was membrane paved and dried to prepare composite membranes. The morphological characteristics were observed by scanning electron microscope(SEM). Composite membranes were placed into cell culture medium, and the supernatant(n=3) was extracted after standing at 6, 12, 24, 36, 48, 60 h, respectively. The concentration of SDF-1 in the solution was measured. Bone mesenchymal stem cells(BMSCs) were cultured in the Transwell room, and the composite membranes containing different concentrations of SDF-1 were placed in the lower chamber. There were four groups(n=3): Group M0 used CS/β-GP membrane(control group), Group M1, M2, M3 used SDF-1/CS/β-GP membrane(SDF-1 was 100, 200, 400 ng/mL respectively). After culture for 6, 12 and 24 h, the cells under the membrane were preserved and Giemsa stained and counted. The absorbance(OD) value was measured by MTT method to calculate the cell proliferation rate. SPSS 19.0 was used for multi-factor analysis of variance. Results : After adding a certain amount of SDF-1 into CS/β-GP solution, the gel time did not change significantly(P>0.05). The SDF-1/CS/β-GP membrane was translucent and porous at 37 ℃. In this experiment, the volumic mass of SDF-1 released by SDF-1/CS/β-GP composite membrane increased gradually with the experimental time(P<0.01). Transwell cell chemotaxis test showed that the number of BMSCs cells with directional migration increased with the prolongation of observation time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). In MTT test, the OD value of migration cell solution increased with the prolongation of time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). Conclusion The SDF-1/CS/β-GP composite membrane has a porous structure and biological activity of chemotactic BMSCs directional migration. It is a potential membrane for guided tissue regeneration.

Objective To investigate the chlorhexidine acetate-resistance in Klebsiella pneumoniae ( K. pneumoniae) clinical isolates and to analyze the possible mechanisms and molecular epidemiology of re-sistant isolates. Methods A total of 332 K. pneumoniae clinical isolates were collected in the First Affilia-ted Hospital of Wenzhou Medical University in 2015. Standard agar dilution was used to screen chlorhexidine acetate-resistant isolates. The minimum inhibition concentrations ( MIC) of chlorhexidine acetate to resistant isolates with and without the presence of carbonyl cyanide m-chlorophenyl hydrazone ( CCCP) , which was an efflux pump inhibitor, were analyzed. Efflux pump genes of cepA, qacE and qacΔE1 that carried by and ex-pressed in those isolates were detected by polymerase chain reaction ( PCR) and quantitative real-time PCR ( RT-qPCR) , respectively. The biofilm formation ability was measured by crystal violet staining. The homol-ogy among the chlorhexidine acetate-resistant isolates was investigated with multilocus sequence typing ( MLST) and pulsed-field gel electrophoresis ( PFGE) . Results Twenty-five K. pneumoniae strains were re-sistant to chlorhexidine acetate. The MIC values of chlorhexidine acetate for them were reduced by at least four-fold in the presence of CCCP. Strains carrying the genes of cepA, qacE and qacΔE1 accounted for 100％, 40％ and 40％, respectively. The expression of the efflux pump genes in the chlorhexidine acetate-resistant isolates was higher than that in the susceptible isolates. The biofilm formation ability of the chlo-rhexidine acetate-resistant isolates was better than that of the susceptible isolates. Furthermore, negative, weak-positive and positive biofilm formation ability was observed in four ( 16％) , 20 ( 80％) and one (4％) strains, respectively. The results of MLST and PFGE showed that the 25 chlorhexidine acetate-resist-ant isolates belonged to 19 different sequence types ( ST) with diverse PFGE patterns. Conclusions This study suggested that active efflux was the main mechanism of chlorhexidine acetate resistance in K. pneumoni-ae. The 25 chlorhexidine acetate-resistant K. pneumoniae strains possessed different biofilm formation ability and shared low homology.

Objective:To evaluate the performance of Autoderm, an artificial intelligence application, in the diagnosis of skin diseases in Chinese patients.Methods:Totally, 920 patients with confirmed skin diseases were prospectively recruited in the Department of Dermatology, the First Affiliated Hospital of Zhengzhou University. Every patient provided 1 clinical image, which was uploaded onto the Autoderm application for the diagnosis of skin diseases. The diagnostic sensitivity, specificity and accuracy of the Autoderm application were estimated, and the kappa values for the diagnostic agreement between the Autoderm application and dermatologists were calculated.Results:Among the 920 patients, 871 (94.7%) could be diagnosed with an Autoderm′s in-distribution skin disease, whereas 49 (5.3%) had out-of-distribution skin diseases. According to the top 1 and 3 diagnoses given by the Autoderm application for the 920 patients separately, its mean diagnostic sensitivities were 41.8% and 65.8%, mean specificities 96.8% and 91.5%, and mean accuracies 92.9% and 89.9%, respectively, and there was moderate overall agreement between the Autoderm application and dermatologists (κ = 0.420, 0.464, respectively). However, for an out-of-distribution skin disease, the Autoderm application could output 5 definitely false diagnoses.Conclusion:Autoderm may be used as as clinical decision support tool for the diagnosis of common skin diseases in most Chinese patients, with moderate diagnostic sensitivity, high specificity, and high accuracy, but misdiagnosis may occur.

The National Comprehensive Cancer Network (NCCN) updates the "NCCN clinical practice guidelines in oncology: Lung cancer screening" annually, and the second edition of 2024 was released in October 2023. The 2024 edition of the guidelines builds on the 2023 edition with some updates on description and assessment of risk factors for lung cancer, evaluation and follow-up of lung nodules found during initial and subsequent screening, and low-dose CT screening protocols and imaging modalities. In this article, we will introduce the above updates and provide reference for lung cancer screening in China by combining the relevant guidelines and consensus in China.