Tumor vaccine is one of the most promising therapeutic strategies in tumor immunotherapy. It promotes the antigen presentation process by delivering tumor antigen and then activates the anti-tumor immune response. As a new class of vaccines, messenger RNA (mRNA) vaccines can activate the immune system to achieve the purpose of immunotherapy by delivering the mRNA sequence of a specific antigen into the body and expressing the corresponding antigen protein. Compared with traditional vaccines, mRNA vaccines have the advantages of a short production cycle, high effectiveness, and strong immunogenicity. In recent years, the application of mRNA vaccines in tumor immunotherapy has attracted widespread attention, but the instability and low delivery efficiency of mRNA limit its application. Nano delivery system can effectively solve the problem of mRNA vaccine delivery, greatly promote the research process and clinical application of mRNA tumor vaccines, and has become a hot spot in the research of mRNA vaccines. In this review, we introduced the mRNA tumor vaccines, focusing on the application of nano delivery system in mRNA tumor vaccines, in order to provide new ideas and new methods for the efficient delivery of mRNA tumor vaccines and tumor immunotherapy.

Objective : To investigate the injury characteristics among primary and middle school students in Panyu District, Guangzhou City, so as to provide the evidence for developing the strategies for prevention and control of injuries. Methods: The data of 6 to 18 years old primary and middle school students with initial diagnosis of injury at Panyu District Central Hospital from 2014 to 2019 were collected. The basic characteristics of injury cases, the causes, time and place of injury development were analyzed by a descriptive epidemiological method. Results: Totally 10 833 primary and middle school students with injury were reported in Panyu District from 2014 to 2019, including 7 401 boys and 3 432 girls, with a boy/girl ratio of 2.16∶1. The injury predominantly occurred in primary school students (6 903 cases, 63.72%). The causes of injury mainly included fall (4 457 cases, 41.14%), animal injury (2 593 cases, 23.94%), blunt injury (1 682 cases, 15.53%), knife/sharp instrument injury (923 cases, 8.52%) and traffic injury (731 cases, 6.75%). The place of injury development mainly included home (4 267 cases, 39.39%), school and public place (3 184 cases, 29.39%), and road/street (1 854 cases, 17.11%). The injury predominantly occurred from August to October (3 289 cases, 30.36%), and the activities at the time of injury mainly included leisure activities (3 860 cases, 35.63%), life activities (2 662 cases, 24.57%) and sports (1 929 cases, 17.81%). The characteristics of injury mainly included contusion/abrasion (4 528 cases, 41.80%), sharp instrument/bite/open injury (4 019 cases, 37.10%) and fracture (871 cases, 8.04%), and the upper limb was the main injury site (3 552 cases, 32.79%). There were 9 877 cases with mild injuries (91.18%), and 10 451 cases left hospitals after seeing a doctor (96.47%). Conclusions Fall is the main causes of injury among primary and middle school students in Panyu District, and boys and primary school students are high-risk groups for injury. Family prevention should be emphasized, and health education pertaining to injury should be intensified among students during the long holidays and leisure activities.

Objective To study the relationship between static duration and bacteria reproduction of pure water from the RO purifier. Methods The original structure of RO purifier was modified by installing additional UV lights and ozone disinfector respectively. Bacteria reproduction in the effluent from RO purifier and modified RO purifier was detected after different static duration. Results The total count of bacteria in the fresh pure water was 20 cfu/ml which was up to the standard of pure drinking water CJ 94-1999. However the total count of bacteria in the pure water will be more than 50 cfu/ml after the pure water was stored inside the tank for six hours, which was not up to the standard of CJ 94-1999. Both ultraviolet rays and ozone could prolong the static duration of pure water, and the efficacy of ultraviolet rays was better than ozone. Conclusion UV light should be installed in RO purifier, the disinfected pure water by UV should be used in 16 hours after disinfection.

Objectives: To explore the influence of exercise training on the arterial baroreflex sensitivity （BRS）and correlation between blood pressure and BRS in spontaneously hypertensive rats (SHR). Methods: Male SHR（n=20）and normotensive Wistar rats（n=20）were randomly assigned to normality group and exercise group, n=10 in each group. Rats in two exercise groups received treadmill training at a speed of 20 m/min for 60 min/d, 6 d/w for eight weeks. Systolic blood pressure (SBP) and heart rate (HR) were measured using a tail-cuff method in a conscious state. Intravenous injections of phenylephrine (PE) and sodium nitroprusside (NP) were used to induce depressor and pressor reflex respectively. The ratio of HR over mean arterial pressure (MAP) (HR /MAP) after administration of PE or NP was regarded as an index of depressor reflex sensitivity (BRS-PE) and pressor reflex sensivity (BRS-NP). Results: After eight-week exercise training, compared with SHR normality group, there were significant reduction in resting SBP [(180±8.5) mmHg vs. (163.6±10.7) mmHg] and in HR [(368.4±13.3) beats/min vs. (345.0±9.8) beats/min] in SHR exercise group, P<0.01 both. However, there was no significant difference in resting SBP between Wistar exercise and normality groups (P>0.05), compared with Wistar normality group, there was significant reduction in HR [(362.2 ± 13.0) beats/min vs. (343.9 ± 10.2) beats/min, P <0.05] in Wistar exercise group. Compared with SHR normality group, there were significant rise in BRS [BRS-PE: (0.89 ± 0.13) bpm/mmHg vs. (1.32 ± 0.22) bpm/mmHg, BRS-NP： (0.60± 0.09) bpm/mmHg vs. (1.21± 0.26) bpm/mmHg, P<0.01] in SHR exercise group, but still lower than those of Wistar normality group [BRS-PE: (1.96±0.23) bpm/mmHg, BRS-NP: (1.32±0.17) bpm/mmHg]. Pearson linear correlation analysis indicated that MAP was significantly inversely correlated with BRS (r=-0.734, P<0.01) in SHR normality and exercise group. Conclusion: Exercise training may significantly decrease SHR blood pressure; it is related to improved baroreflex sensitivity induced by exercise, indicating that enhanced baroreflex may be an important mechanism of exercise therapy in hypertensive patients.

The specific primers and Taqman probe were designed and synthesized according to the UL31 gene sequence available in GenBank(EF417996).The fragment is 76 bp.A Taq Real-time fluorescent quantitative PCR assay was established for detection of Duck Plague Virus DNA based on DNA copy obtained from attenuated vaccine strain as a positive template.The sensitivity of the test for DEV is 2.1 × 100-2.1 × 109 copies.The minimum detection limit is 2.1 copies(2.1 fg).Tissues,excrement and blood of 4 ducks challenged with DEV were detected repeatly 3 times by this method.All results were positive (3/3).The specificity of the assay was proven based on no amplification by detecting DNA from normal duck cells,duck viral hepatitis virus,Pasteurella,E.coli,S.gall inarum,Newcastle disease virus,goosling plague virus et ai.The whole process of the test could be completed within 4 hours.It brings about quantification detection of DEV DNA.

rvice employees had a low scores as comparing with their salaries, benefits and workloads.And 28.2% employees had once the idea of resigning.

Background and purpose: Systemic reports about the prognosis of patients with renal cell carcinoma (RCC) of stage T_(1-3a)N_0M_0 combined with inflammatory enlargement of hilar lymph nodes have not been observed in the literature. This study was to investigate the prognostic role of inflammatory enlargement of hilar lymph nodes in the patients with RCC of stage T_(1-3a)N_0M_0 and its association with clinical features. Methods; Forty-nine patients with RCC of stage T_(1-3a)N_0M_0 combined with inflammatory enlargement of hilar lymph nodes were reviewed and all these patients underwent radical nephrectomy from January 1995 to January 2000. Results: The duration of follow-up was 8-14 years with the average of 7.5 years. Seven patients were lost to follow-up. Seventeen patients without RCC and four with RCC metastases are alive at present. Eighteen patients died of RCC relatad complications and three died of cerebro-cardiovascular disease. Metastases occurred in twenty-two patients one year after surgery. The 5- and 10- year survival rates were 53.1% and 42.9%, respectively. Conclusion: Most of the enlarged hilar lymph nodes in RCC were diagnosed as lymphadenitis. The rate of inflammatory enlargement of hilar lymph nodes in the long-term survival patients with RCC of stage T_(1-3a)N_0M_0 were comparatively low. Regional lymphadenectomy or resection of enlarged inflammatory lymph nodes could not protect the patients from metastasis completely. It is advised that limited lymphadenectomy with resection of enlarged inflammatory lymph nodes should be performed for the patients in RCC combined only with inflammatory enlargement of hilar lymph nodes.

BACKGROUND:As an important industrial solvent,benzene can cause DNA damage,chromosome aberrence,formation of DNA adducts and gene mutation. OBJECTIVE:To explore the effects of benzene on DNA and the mechanism,as well as the changes of antioxidase system it caused. DESIGN:Randomized case control study. SETTING:The Department of Clinical Laboratory of First Affiliated Hospital and Public Health College of Harbin Medical University. PARTICIPANTS:The experiment was completed in the Animal Centre in Public Health College,Harbin Medical University.Twenty-four healthy male mice of Kunming species weighed between 18 g to 22 g were chosen.The mice were provided by Experimental Animal Centre of Second Affiliated Hospital,Harbin Medical University. INTERVENTIONS:The mice were divided into control group,low dose benzene group and high dose benzene group.Inhaling benzene smoke method was used 4 hours per day to cause benzene poisoning to mice except those of the control group.The mice were executed two months later to separate marrow cells and peripheral lymphocytes and remove liver,spleen and brain to make homogenate. MAIN OUTCOME MEASURES:Single cell gel electrophoresis (SCGE) was used to assay the DNA damages of marrow cells and peripheral lymphocytes.Meanwhile,the contents of superoxide dismulase(SOD),glutathione peroxidase(GSH-Px) and malondialdehyde(MDA) in liver,spleen and brain tissues were also detected. RESULTS:The comet percentage of marrow cells and peripheral lymphocytes in two benzene poisoning groups were(83.56± 10.28),(92.54± 15.93)% ,and(41.27± 6.03)% ,(65.79± 11.62)% respectively which were much higher than those in control group[(4.13± 0.52)% ,(2.21± 0.31)% ](P< 0.01) and represented dose-response relationship.The SOD activity of liver homogenate and GSH-Px activity of high dose and low dose groups were (11 573.31± 1 938.72),(12 574.68± 1 938.72) nkat/g and (309.40± 82.85),(375.41± 55.18) nkat/g respectively which were much lower than those in control group [(16 668.67± 3 137.96),(588.62± 110.52) nkat/g] (P< 0.05).However, there was no significant difference between different dose groups. The GSH-Px activity in spleen homogenate in two experimental groups was(421.75± 124.02) and(523.10± 45.18) nkat/g respectively which was much lower than that of control group [(618.42± 57.01) nkat/g](P< 0.05) and there was significant difference between two groups (P< 0.05).In the brain homogenate of both benzene groups,the GSH-Px activity was(87.35± 19.84) and(95.02± 14.00) nkat/g respectively which was much lower than that of control group[(118.36± 7.67) nkat/g] (P< 0.05) and without difference between two groups.The MDA content in brain homogenate of high dose group was(3.99± 1.15) μ mol/mg which was much higher than that of control group [(2.58± 0.53) μ mol/g] (P< 0.05). CONCLUSION:Chronic benzene poisoning can cause DNA impairment of marrow cells and peripheral lymphocytes and reduce the activity of antioxidase.

Objective To approach the protective effect of dexmedetomidine on mechanically ventilated patients with pulmonary contusion. Methods A prospective randomly controlled trial was conducted. 70 mechanically ventilated patients with pulmonary contusion from January 2010 to December 2012 in the Critical Care Medicine of Foshan Hospital of Traditional Chinese Medicine were divided into a control group and a therapy group by the difference in number odd or even,with 35 patients in each group. Based on the same principles of comprehensive treatment,the control group used midazolam,and the therapy group used dexmedetomidine for sedation. The measured parameters included oxygenation index(PaO2/FiO2),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6), and extra-vacular lung water index(EVLWI)for both groups on the1st and 5th day. The incidence of delirium,the time of mechanical ventilation,and the incidence of hypotension were observed in both groups. Results Compared with those on the 1st day,TNF-α,IL-6 and EVLWI on the 5th day were decreased significantly in both groups〔the control group TNF-α(ng/L):1.29±0.38 vs. 2.21±0.37,IL-6(ng/L):97.97±28.77 vs. 131.03±41.52,EVLWI (mL/kg):8.25±2.03 vs. 11.96±3.36;the therapy group TNF-α:1.06±0.33 vs. 2.32±0.37,IL-6:82.07±23.35 vs. 134.98±64.25, EVLWI(mL/kg):6.74±1.33 vs. 11.23±2.78, all P<0.05〕, PaO2/FiO2 was increased obviously〔mmHg(1 mmHg=0.133 kPa),the control group:285.80±30.65 vs. 213.00±33.70,the therapy group:315.00±34.50 vs. 229.50±37.00,both P<0.05〕,TNF-αand IL-6 had no significant difference compared between the therapy group and control group(TNF-α:1.06±0.33 vs. 1.29±0.38,IL-6:82.07±23.35 vs. 97.97±28.77), while EVLWI and PaO2/FiO2 in the therapy group had remarkable differences compared with those of the control group〔EVLWI(mL/kg):6.74±1.33 vs. 8.25±2.03,PaO2/FiO2(mmHg):315.00±34.50 vs. 285.80±30.65,both P<0.05〕. The incidence of delirium(8.57% vs. 22.86%)and time of mechanical ventilation(day:4.10±1.09 vs. 6.88±1.66)in the therapy group were decreased markedly compared with those of the control group,and the incidence of hypotension had no significant difference between treatment or control groups(17.14% vs. 14.29%,P>0.05). Conclusion Dexmedetomidine has protective effect on mechanically ventilated patients with pulmonary contusion, and it is an relatively ideal sedative drug for these patients.

Objective:To evaluate the reliability and validity of the Clinical Reception Attitude Scale .Meth-ods:Based on the survey of 311 outpatients from 4 first-class hospitals , the test-retest reliability , internal con-sistency , construct validity , criterion validities and discriminant validity of the scale was tested .Results:The test-retest reliability was 0.901, the internal consistency was 0.973, 4 common factors accounted for 80.0%of the total variation, the items of which matched the construct of the scale , the criterion validities were 0.856 and 0 .810 , the discriminant validity was good .Conclusions: The results indicated the Clinical Reception Attitude Scale had good reliability and validity .The adjusted scale is an effective tool for the investigation of clinical recep-tion attitude of doctors in China .