Objective To investigate the effects of plateau hypoxia on the growth and tumor microenvironment of colorectal carcinoma in vivo.Methods A total of 16 male BALB/C mice(6 weeks old,weight 18-20 g)were randomly divided into plateau hypoxic group and plain normoxic group,with 8 mice in each group,while 14 male C57BL/6 mice were grouped in same way,with 7 mice in each group.The mice in the plateau hypoxic group were housed in a low-pressure oxygen(10%)chamber to simulate an altitude of approximately 5 600 m,while the mice of the other group was maintained in SPF-grade normal atmospheric conditions(21%oxygen,at an altitude of about 300 m).Colorectal tumor MC38 cells and colon adenocarcinoma CT26 cells were subcutaneously implanted into C57BL/6 mice and BALB/C mice,respectively to construct subcutaneous tumor-bearing mouse models.Then the tumor size and weight were measured in 4 groups of mice.After the tumor tissues,spleen and blood samples were collected in the C57BL/6 mice.Flow cytometry was used to determine the percentages of macrophages,T lymphocytes,IFN-γ+T lymphocytes,and myeloid-derived suppressor cells(MDSC).The differences in these immune cells were compared between the cells from the plateau hypoxic group and those from the plain normoxic group.Results The weight of subcutaneous tumor mass was significantly inhibited in both C57BL/6 and BALB/C mice from the plateau hypoxic group than those from the 2 plain normoxic groups(0.17 vs 0.09 g,1.38 vs 0.51 g,P<0.01).When compared with the immune cells from the tumor mass of the plain normoxic C57BL/6 mice,the percentage of M2-type macrophages was reduced in the tumor tissue from the plateau hypoxic mice(22.13%vs 15.90%,P<0.05),so was that of MDSC(2.06%vs 1.05%,P<0.01),particularly in the monocytic(M)-MDSC subgroup(60.97%vs 41.13%,P<0.01).While,no significant change was observed in the proportion of the polymorphonuclear(PMN)-MDSC subgroup(10.97%vs 9.70%,P>0.05).Additionally,the percentage of CD4+T cells was significantly reduced(48.70%vs 41.93%,P<0.05),whereas that of CD8+T cells was obviously increased(41.25%vs 51.18%,P<0.05),along with a notable rise in the proportions of IFN-γ+T,IFN-γ+CD4+T and IFN-γ+CD8+T cells(28.58%vs 59.65%,23.33%vs 53.65%,36.9%vs 66.48%,P<0.01).However,between the peripheral blood samples of the 2 groups of C57BL/6 mice,the proportions of M1-type macrophages and CD4+T cells were reduced(84.98%vs 78.43%,5.86%vs 4.01%,P<0.01),and those of MDSC and PMN-MDC were increased(4.47%vs 16.43%,36.56%vs 62.97%,P<0.01).In the spleen tissues,notable decreases were observed in the proportions of CD8+T cells and IFN-γ+CD8+T cells between the 2 groups(33.05%vs 27.68%,5.13%vs 1.58%,P<0.01).Conclusion Plateau hypoxia improves the immune response within the tumor microenvironment,and inhibits subcutaneous tumor growth of colorectal cancer,but suppresses systemic immune response.

Objective To investigate the social support needs of medical staff in Guangzhou during the post-COVID-19 period,providing a basis for relevant departments to offer targeted social support for medical staff in Guangzhou and improve their of occupational quality of life.Methods A cross-sectional survey was conducted,employing a combination of quota and conven-ience sampling to select subjects,eligible medical staff were invited to complete an online questionnaire.Results The social sup-port with a total score of 20 for medical staff in Guangzhou scored 9(7,11).Among the dimensions of social support,media sup-port scored the lowest.Social support as a whole scored with statistically significant differences across groups of different age,ed-ucational background,and job position(all P＜0.05).The median score was the lowest for those under 25 years,for those with a college degree or below,and highest among administrative staff,with other positions showing equal median score.The five di-mensions of social support ranked on the top concerning the total number of the respondents included patients'understanding and trust for medical staff(93.03％),increasing in salaries and benefits(86.06％),accurate policy promotion and public opinion guidance by media(83.41％),attention to the living conditions of medical staff by media(80.29％),and enhanced regulation of false reporting and inappropriate commentary by media(76.92％).Medical staff under the age of 25 had a high need for pa-tients'following doctor's advice,and medical staff with a collegiate degree or below had a high need for family members or friends to care about their physical and mental health.The five strongest needs for social support ranked on the top concerning the total number of respondents included understanding and trust from patients(75.72％),increased salaries and benefits(53.85％),assistance with household matters by family or friends(42.55％),correct policy promotion and public opinion guidance by media(34.62％),and attention to the living conditions of medical staff from media(33.41％).Conclusion Social support for medical staff in Guangzhou are at a relatively low level,indicating a need for social support from all levels of society.

Objective This study explores the implementation and effects of the"Hong Kong and Macau Medical Device and Pharmaceutical Access"policy at Nansha Hospital of Guangzhou First People's Hospital within the context of the Guangdong-Hong Kong-Macao Greater Bay Area construction.Through specific case analysis,it evaluates the practical application of the poli-cy and proposes improvement suggestions.Methods A systematic analysis was conducted on the specific measures taken by Nansha Hospital of Guangzhou First People's Hospital in terms of organizational structure,system construction,operational man-agement,and multi-form publicity.Results During the policy implementation,the hospital obtained approval for 7 urgently nee-ded medical devices and pharmaceuticals,with a total of 20 uses,benefiting 18 patients.These innovative measures significantly improved the hospital's medical service quality and efficiency but also exposed some issues,such as medical risk control,drug diversion,medical insurance reimbursement,and training and adaptation of medical staff.Conclusion Based on the findings,this paper proposes targeted improvement suggestions to provide references for other medical institutions in implementing the"Hong Kong and Macau Medical Device and Pharmaceutical Access"policy and to offer insights for further optimization of the policy.