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 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.

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.

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.

This study was aimed to compare different preparation methods of Wei-Chang Fu-Yuan (WCFY) De-coction, which is a self-made traditional Chinese medicine (TCM) decoction of our hospital, through the investiga-tion of difference in recovery time of gastrointestinal function after gynecological abdominal surgery. A total of 120 cases after gynecological abdominal surgery in our hospital between 2011 and 2012 were randomly divided into the treatment group and the control group, with 60 cases in each group. The hospital self-made WCFY Decoction was given to patients 8 hours after surgery in the treatment group and control group. Decoctions given to two groups were prepared with different methods. Decoction given to the treatment group was by the decoction ma-chine of multiple decoctions preparation. Decoction given to the control group was prepared as the traditional sin-gle dose decoction. The first anus flatus time was observed in both groups. The results showed that the flatus time of treatment group was 16 h and that of the control group was 13 h. The flatus time of patients from two groups was in skewed distribution, so the distance between the median and quartile was used to describe. The non-para-metric tests (Kolmogorov-Smirnov method) were used in the comparison of flatus time of two groups. There was statistical significance between two groups (P < 0.05). It was concluded that different preparation methods affect the clinical efficacy of WCFY Decoction. Compared with the traditional single dose decoction, the fist flatus time was postponed 3 hours by the decoction machine of multiple decoctions preparation. Therefore, with the widely using of decoction machine of multiple decoctions preparation today, the function of decoction machine should be improved and the program should be perfected in order to increase the clinical efficacy of this preparation method.

Objective To objectively evaluate the intrusion effects on the maxillary incisors of implants versus conventional method(J-hook headgear ,utility arch) .Methods Such online databases as Cochrane library ,PubMed ,EMbase ,VIP ,Wanfang and CNKI were searched by randomized control test and prospective case controlled study about implants vs conventional anchorage for the maxillary incisor intrusion .After study selection ,assessment and data extraction conducted ,meta-analyses were performed by u-sing the RevMan 5 .1 software .Results Totally 11 studies were included ,6 studies involving 154 patients were included in the J-hook headgear group ,5 studies involving 127 patients were included in the utility arch group .The results of meta-analyses showed that :(1)Compared with the J-hook headgear ,implants had more decrement in the distance of upper center incisior cutting to palatal plane(P<0 .001) ,more decrement in overbite(P=0 .001) ,shorter treatment time (P<0 .001) ,less increase in SN-OP angle(P=0 .004) ,less decrement in distance of maxillary molar cusp to palatal plane (P=0 .020);There was no statistically significant differ-ence in overjet ,root resorption(P>0 .05) .(2)Compared with the utility arch ,implants had more decrement in the distance of the center of resistance of the upper incisor to palatal plane (P=0 .010) ,less increase in U6-PP angle (P<0 .001);There was no statis-tically significant difference in the distance of upper center incisior cutting to palatal plane ,U1-PP angle ,the distance of upper first Molar cutting to palatal plane ,sagittal position of the mesial tip of the upper first Molar ,overbite ,overjet ,course of treatment ,root resorption(P>0 .05) .Conclusion The implants anchorage intruded the maxillary incisor was better than conventional method (J-hook headgear ,utility arch) ,it has more incisor intrusion ,shorter treatment time and more comfortable for the patients ,there was no difference in root resorption between the two groups .

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

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 .

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.

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.