Objective: To prepare a new type of phycocyanin/carboxymethyl chitosan-CD55 ligand peptide (CPC/CMC-CD55sp) nanospheres, and to study its targeted therapeutic effect on cervical cancer Caski cells. Methods: The novel CPC/CMC-CD55sp nanospheres (CPC/CMC-CD55sp) were synthesized by ionic cross-linking method, and the properties of nanospheres were observed by transmission electron microscopy (DLS) and fourier transform infrared spectroscopy (FTIR). The expression of CD55 on the surface of Caski and fibroblast (L-929) cells was detected by Western blotting and flow cytometry. The effect of nanospheres on the proliferation of Caski cells was detected by CCK-8. Flow cytometry and fluorescence microscopy were used to detect the uptake of microspheres by Caski cells; Western blotting and flow cytometry were used to detect the effect of CPC/CMC-CD55sp on expressions of apoptosis-related proteins and apoptosis rate in Caski cells; the hemolysis test was used to determine the biological safety of the drug. Results: CPC/ CMC-CD55sp was successfully prepared with good morphology and uniform diameter; and CD55 was highly expressed on the surface of Caski cells but low expressed on the surface of L-929 cells (P<0.01). CPC/CMC-CD55sp could targeted and efficiently reach Caski cells and be ingested into the cells. It exhibited weak hemolysis effect on human peripheral blood, which was in the safe range. CPC/ CMC-CD55sp displayed obvious inhibitory effect on Caski cell proliferation, and could induce cell apoptosis (P<0.05 or P<0.01). Conclusion: The new CPC/CMC-CD55sp can targeted inhibit the growth of cervical cancer Caski cells via inducing its apoptosis and has good bio-safety, which provides a new idea for the research and development of anti-tumor marine drugs.

Objective    To analyze the influencing factors for re-positive nucleic acid test in discharged corona-virus disease 2019 (COVID-19) patients in Chengdu, Sichuan Province, and to provide data support for the epidemics prevention and control. Methods    The clinical data of 660 discharged COVID-19 patients from January 23, 2020 to February 28, 2021 in our center were retrospectively analyzed. The patients were divided into two groups according to the reexamination of virus nucleic acid, including a negative group [549 patients, including 428 males and 121 females with a median age of 33.0 (28.0, 48.0) years] and a positive group [111 patients, including 76 males and 35 females with a median age of 39.0 (28.0, 51.0) years]. The clinical data of the two groups were compared. Results     The re-positive rate of the discharged patients was 16.82%. Univariate analysis showed that the re-positive rate of females was higher than that of males (χ2=4.608, P=0.032). The re-positive rate of confirmed patients was higher than that of asymptomatic infected patients (χ2=8.140, P=0.004). The re-positive rate of domestic patients was higher than that of imported patients (χ2=9.178, P=0.002). The counts of CD3+ (P=0.038), CD4+ (P=0.048) and CD8+ (P=0.040) T lymphocytes in the negative group were higher than those in the positive group. The binary logistic regression analysis showed that the clinical classification and CD8+ T lymphocyte count were independent risk factors affecting the recurrence of virility. Conclusion    The gender, origin, T lymphocyte subsets count and clinical type are the influencing factors for re-positive result, and clinical type and CD8+ T lymphocyte count are the independent influencing factors for re-positive result. Therefore, improving the immunity of infected patients, as well as early detection and timely treatment are effective means to reduce the re-positive occurrence.