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Objective To provide references for scientific training and medical care by investigating the characteristics and influencing factors of the training injuries of the freshmen in a military medical university during their long-distance trek training. Methods The medical data of the injuries for 318 freshmen during the trekking from October 10 to 19, 2019 were collected and analyzed with cross-sectional study. Then 60 male freshmen who used insoles and another 60 who did not were retrospectively recruited as insole group and control group, respectively to observed the incidence and numbers of foot blisters during the training. In addition, the onset time of the acute gastroenteritis outbreak were also studied with in-depth analysis. Results For the 318 freshmen taking part in the whole training, there were totally 813 admissions for medical support, with a rate of 255.66%. The common injuries included foot blisters, soft tissue injuries, upper respiratory tract infection, acute gastroenteritis and abrasion. And the number of medical visits for the first 4 causes took up to 600, accountting for 73.90% of the total diagnosis and treatment. Besides, the insole significantly decreased the rate and number of foot blisters (P=0.006). Contaminated drinking water was the main cause of acute gastroenteritis. The incidences of various injuries showed obvious relationship with the training plan. Conclusion The injury spectrum and injury characteristics of the freshmen in a long-distance trek training show certain rules, with foot blisters, soft tissue injuries, upper respiratory tract infection and acute gastroenteritis most common. Insole use could effectively prevent the occurrence of foot blisters. And paying attention to drinking water hygiene is useful to prevent acute gastroenteritis outbreak.

Objective To explore the synergistic effect of ceftazidime/avicarbam combined with aztreonam against carbapenem-resistant isolates of Klebsiella pneumoniae (CRKP). Methods We collected 10 clinical isolates of CRKP from our hospital and determined the minimal inhibitory concentrations of the commonly used antibiotics in these isolates using agar plate double-dilution method. The carbapenemase genes and extended-spectrum β-lactamase genes of the bacteria were amplified by PCR, and the expression of carbapenemase genes was detected by RT-PCR. The bacterial genotypes were analyzed with multilocus sequence typing. The synergistic effect of ceftazidime/avicarbam combined with aztreonam against these CRKP isolates was determined using the checkerboard method. Results The 10 CRKP isolates were all sensitive to tigecycline but highly resistant to all the other antibiotics tested. The β-lactamase genes (NDM, CTX-M and SHV) were widely distributed in these isolates, and the strains with a high resistance to carbapenem also had high expression levels of carbapenemase genes (r=0.805, P=0.029). Four distinct ST genotypes were identified among the CRKP strains, and the genotype ST11 had the highest epidemic potential; NDM gene was present in the strains of 3 different ST genotypes. Ceftazidime/avicarbam combined with aztreonam showed a synergistic inhibitory effect in 7 CRKP strains and produced irrelevant effects in the other 3 strains. Conclusion The high resistance of CRKP strains can be attributed to the resistance genes they carry, and the combination of ceftazidime/avicarbam and aztreonam can produce a strong synergistic inhibitory effect in these strains.carbapenem-

Based on the requirements of high efficiency, energy saving, batch production, stable supply and environmental protection, the microstructure and properties of magnesium alloy under non-flux remelting are determined. Taking ZM5 magnesium alloy as the research object, the non-flux remelting process parameters of ZM5 magnesium alloy are analyzed by orthogonal test and variance method. The results show that the melt holding time has the greatest influence on the mechanical properties, followed by the melt holding temperature and the gas stirring time. The optimum parameters for obtaining good mechanical properties are as follows: holding time of melt of 40 min, holding temperature of melt of 740 °C, and gas stirring time of 3 min. The microstructure of ZM5 magnesium alloy is also studied. The results show that the original ZM5 ingot has very large grains and abundant dendrites. After non-flux free, ZM5 Alloy contains impurity elements such as O, C, Si in addition to the elements in the alloy. Non-flux remelting has no obvious effect on the solidification process of ZM5 Alloy, and there is no hereditary structure after remelting. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the immunogenicity and osteogenic ability of animal-derived bone graft material decellularized with supercritical carbon dioxide., Methods: Porcine femurs were randomly divided into two groups after preliminary treatment, and decellularized with conventional method (conventional control group) or supercritical carbon dioxide (experimental group). Clearance rate of galactose-α-1, 3-galactose (α-Gal) and residual DNA of the two groups were analyzed to assess the immunogenicity of the xenogenic materials. Clearance rate of α-Gal was determined by enzyme-linked immunosorbent assay and residual DNA was detected by fluorescence method. Nine SPF-grade male athymic nude mice of 6 weeks old were randomly divided into experimental group, conventional control group and positive control group. Samples were implanted over biceps femoris muscle of athymic nude mice, the explants were collected 4 weeks post implantation, hematoxylin and eosin (HE) staining and immunohistochemistry were applied to determine the osteogenic ability and bone tissue-associated protein expressions of the implants., Results: The clearance rates of α-Gal antigen in the experimental group and the conventional control group were (99.09±0.26)% and (30.18±2.02)%, respectively ( t =58.67, P< 0.01). The residual DNA of the experimental group, the conventional control group and the positive control group were (13.49±0.07) ng/mg, (15.20±0.21) ng/mg and (14.70±0.17) ng/mg, the residual DNA in the experimental group was significantly lower than that in the conventional control group ( t =－13.41, P <0.01) and the positive control group ( t =－11.30, P <0.01). HE staining showed that multiple bone formation centers with active osteogenesis and rich bone marrow were observed in experimental group 4 weeks after implantation, only a small number of bone formation centers were observed in the conventional control group and the positive control group, with no obvious osteoblasts present. Immunohistochemistry results indicated that the expressions of alkaline phosphatase, Runt-related transcription factor 2, typeⅠcollagen and osteocalcin in the experimental group showed an increasing trend compared with those in the conventional control group and the positive control group., Conclusions: Compared with clinically used demineralized bone matrix and bone graft material decellularized with conventional method, bone graft material decellularized with supercritical carbon dioxide exhibits lower immunogenicity and better osteogenic ability.

Objective: To construct a magnetic and catalytic hairpin assembly-based platform for detection of dual membrane proteins on exosomes., Methods: Exosomes in supernatant of breast cancer MDA-MB-231 cell culture were separated, purified and characterized. Super-resolution imaging and Western blotting were performed to confirm the expression of the membrane protein CD63 on the exosomes. Polyacrylamide gel electrophoresis was used to verify the combination of Apt EpCAM -T and exosomes. Fluorescence experiments were carried out to test the feasibility of CHA nucleic acid sequence, optimize the reaction conditions, and determine the specificity of the detection platform., Results: Super-resolution imaging and Western blotting showed that breast cancer MDA-MB-231 cell-derived exosomes expressed abundant membrane protein CD63. Polyacrylamide gel electrophoresis indicated that Apt EpCAM -T could recognize and bind to exosomes. The results of specificity test showed that the signal-to-noise ratio of the detection platform was 1.10±0.01 for detecting normal human breast epithelial cell-derived exosomes, and was 2.09±0.08 for breast cancer cell-derived exosomes., Conclusions: Magnetic and catalytic hairpin assembly-based detection platform allows simultaneous detection of two membrane proteins expressed on exosomes and identification of the expressions of membrane proteins on exosomes from different sources.

Objective: To determine the sperm-zona pellucida (ZP) binding and ZP-induced acrosome reaction in patients with unexplained infertility, and to discuss the relationship between ZP-induced acrosome reaction and fertilization rate., Methods: We compared the fertilization rate and good embryo rate in patients with unexplained infertility after fertilization in 2 ways. Based on the causes of infertility, patients were divided into an unexplained infertility group (Group A) and a pure female tubal factor group (Group B). Oocytes which were obtained by super ovulation from 25 patients with unexplained infertility were randomly divided into 2 groups with conventional in vitro fertilization (IVF) (Group A1) and intracytoplasmic sperm injection (ICSI) fertilization (Group A2). The pure female tubal factor group (Group B) had conventional IVF. We conducted sperm-ZP binding and ZP-induced acrosome reaction experiments with 2 groups of men's sperms separately. We compared the number of sperm-egg binding and ZP-induced acrosome reaction rate and discussed the relationship between the ZP-induced acrosome reaction and fertilization rate, and also the fertilization rate, good embryo rate and pregnancy rate in patients with unexplained infertility after fertilization in 2 ways., Results: The average number of sperm-egg binding (78.29 ± 16.31) and the ZP-induced acrosome reaction rate (55.87 ± 27.69) % in Group A were lower than those of Group B [94.63 ± 6.72, (82.53 ± 17.99)%]. The difference between the average number of sperm-egg binding and the ZP-induced acrosome reaction was significant (P <0.01). The fertilization rate of Group A1 was significantly lower than that of Group B and Group A2 (P <0.01). But there was no significant difference in the good embryo rate among the 3 groups. There was no significant difference between Group A2 and B in fertilization rate and good embryo rate (P <0.05). There was no significant difference in pregnancy rate between Group A and B (P <0.05). Fertilization rate and the rate of acrosome reaction had marked positive correlation with statistical significance (r =0.932, P <0.01)., Conclusion: ZP binding and ZP-induced acrosome reaction are very important experiments in sperm function test for patients with unexplained infertility. It can not only effectively avoid no embryo transferring due to complete failure of fertilization but also get a desirable outcome of pregnancy using half-ICSI fertilization in patients with unexplained infertility.

Objective: To evaluate the impact of sperm source and sperm parameters on the outcome of intracytoplasmic sperm injection (ICSI)., Methods: This retrospective study included 433 ICSI cycles from June 2005 to December 2008 in Reproductive Medical Center of Xiangya Hospital. The patients were divided into 2 major groups according to the source of spermatozoa used for ICSI: ejaculated (group A, n=336) and epididymal (group B, n=97). Group A was divided into 3 subgroups according to the sperm parameters: normal (Group A1, n=95), single parameter defect (Group A2, n=119), and multiple parameter defect (Group A3, n=122)., Results: The basic characteristics among the 4 groups had no statistic difference (P>0.05), and the difference in the fertilization rate, normal fertilization rate, cleaving embryo rate,good quality embryo rate, implanted rate, clinical pregnancy rate, and early abortion rate among the 4 groups were not significant (P>0.05)., Conclusion: The outcome is similar no matter whether the spermatozoa is from ejaculated sperm or epididymis. ICSI can treat male infertility of various factors, and the outcome is the same with one or multiple sperm parameter abnormality. ICSI with epididymal spermatozoa through percutaneous epididymal sperm aspiration is effective for infertility due to obstructive azoospermia.

Objective: To explore the different effect of short 7-day gonadotropin releasing hormone agonist (GnRHa) protocol and GnRHa long protocol on the insulin-like growth factor II(IGF-II) and insulin-like growth factor binding protein-4 (IGFBP-4) levels in follicular fluid., Methods: Eighty-eight infertile patients due to tubal factors were included in this study. They were randomly divided into a short 7-day GnRHa protocol group and a GnRHa long protocol group (n = 44). Follicular fluid was obtained from dominant follicles during oocyte retrieval. Levels of IGF-II and IGFBP-4 in the follicular fluid were detected by radioimmunoassay and enzyme-linked immunosorbent assay respectively., Results: Duration of controlled ovarian stimulation was significantly shorter and the injected dosages of gonadotropin were significantly lower in the short 7-day protocol group. The differences in serum levels of estradiol and estradiol per mature follicle on the day of human chorionic gonadotropin injection between the two groups were not significant. The concentrations of IGF-II and IGFBP-4 in the follicular fluid of the short 7-day protocol group were significantly lower,while the difference of the ratio of IGF-II/IGFBP-4 between the two groups was not significant. Linear correlation analysis showed that IGF-II level in the follicular fluid was positively correlated to the total dose of gonadotropin., Conclusion: The short 7-day and long GnRHa protocols may affect the concentrations of IGF-II and IGFBP-4 in the follicular fluid. However, changes of IGF-II and IGFBP-4 concentrations do not contribute to different clinical outcomes.