ABSTRACT
Objective @#By testing the tensile strength of the poly(vinyl alcohol) (PVA)/bacterial cellulose(BC) composite membrane and its effect on the proliferation of mouse embryonic fibroblasts, its potential as new bone tissue engineering membrane were studied.@*Methods @#PVA⁃BC films of different proportions and pure PVA films were prepared by self⁃evaporation method. The tensile strength of each group was tested. The group with the highest tensile strength was immersed in deionized water for 0. 5 h to measure its wet tensile strength. The microstructure of pure PVA film and the film with the highest tensile strength was observed by scanning electron microscopy (SEM) .X⁃ray diffraction and Fourier transform infrared ( FTIR) spectroscopy were used to analyze pure PVA, pure BC,and the film with the highest tensile strength respectively. Cell counting kit⁃8 (CCK⁃8) was applied to detect the survival rate in the blank control group, the pure PVA film group, and the composite film group with the highest tensile strength. @*Results @#PVA⁃BC composite films were successfully prepared, X⁃ray diffraction and FTIR analysis revealed the co⁃presence of PVA and bacterial cellulose in the composite film. The initial tensile strength of the composite membrane increased with the BC ratio. When the concentration ratio of PVA to BC was 10 ∶ 7, the tensile strength reached (155. 5 ± 14. 7) MPa, and wet samples reached (13. 8 ± 1. 2) MPa. The CCK⁃8 test of NIH/3T3 showed that there was no significant difference among the PVA⁃BC composite film group, pure PVA group and blank control group after 1,4 and 7 days of cell culture ( P > 0. 05 ) . @*Conclusion @#PVA⁃BC film fabricated by blending method obtain certain mechanical properties and biocompatibility in both wet and dry states, which may be an appropriate candidate as a GBR membranes for clinical application.
ABSTRACT
AbstractsO_ST_ABSBackgroundC_ST_ABSCancer patients are considered to be highly susceptible to viral infections, however, the comprehensive features of COVID-19 in these patients remained largely unknown. The present study aimed to assess the clinical characteristics and outcomes of COVID-19 in a large cohort of cancer patients. Design, Setting, and ParticipantsData of consecutive cancer patients admitted to 33 designated hospitals for COVID-19 in Hubei province, China from December 17, 2019 to March 18, 2020 were retrospectively collected. The follow-up cutoff date was April 02, 2020. The clinical course and survival status of the cancer patients with COVID-19 were measured, and the potential risk factors of severe events and death were assessed through univariable and multivariable analyses. ResultsA total of 283 laboratory confirmed COVID-19 patients (50% male; median age, 63.0 years [IQR, 55.0 to 70.0]) with more than 20 cancer types were included. The overall mortality rate was 18% (50/283), and the median hospitalization stay for the survivors was 26 days. Amongst all, 76 (27%) were former cancer patients with curative resections for over five years without recurrence. The current cancer patients exhibited worse outcomes versus former cancer patients (overall survival, HR=2.45, 95%CI 1.10 to 5.44, log-rank p=0.02; mortality rate, 21% vs 9%). Of the 207 current cancer patients, 95 (46%) have received recent anti-tumor treatment, and the highest mortality rate was observed in the patients receiving recent chemotherapy (33%), followed by surgery (26%), other anti-tumor treatments (19%), and no anti-tumor treatment (15%). In addition, a higher mortality rate was observed in patients with lymphohematopoietic malignancies (LHM) (53%, 9/17), and all seven LHM patients with recent chemotherapy died. Multivariable analysis indicated that LHM (p=0.001) was one of the independent factors associating with critical illness or death. ConclusionsThis is the first systematic study comprehensively depicting COVID-19 in a large cancer cohort. Patients with tumors, especially LHM, may have poorer prognosis of COVID-19. Additional cares are warranted and non-emergency anti-tumor treatment should be cautiously used for these patients under the pandemic.