AIM: To purify and refold the inclusion body of a human anti-HBsAg scFv with a 6?His tag, and to determine the affinity constant of the purified recombinant product.METHODS: Solubilizing in buffers containing urea or guanidine hydrochloride (GuHCl), the inclusion body was purified by IMAC, and then refolded by dialysis against urea or GuHCl, at the same time, Ni 2+ charged chelate column was utilized for in situ refolding. The affinity constant of the refolded scFv, polished by immune-affinity chromatography, was determined by non-competitive ELISA. RESULTS: The refolded scFv with highest specific bioactivity was produced by dialysis against GuHCl. Under this condition, the recovery of target protein reached (61.08?1 45)%. The affinity constant of the polished scFv was confirmed to be(2.30?0.32) ?10 7 L/mol. CONCLUSION: The inclusion body studied in this paper can be refolded efficiently under optimal dialysis condition in vitro . The antigen-binding property of this recombinant scFv is not affected by the purification tag fused to the N terminal of the protein.

Background and purpose:Although bortezomib has become one of the major therapeutic agents against newly diagnosed or relapsed multiple myeloma (MM), there are some patients who become resistant to bor-tezomib and then relapse, emerging as a major obstacle to long-term survival of MM patients. It has been found that elevation of intracellular cyclic adenosine monophosphate (cAMP) levels could induce cell cycle arrest and apoptosis in MM cells,which has become an interesting approach to MM therapy. This study aimed to investigate possible effects of forskolin combined with bortezomib on bortezomib-resistant myeloma cells and further explore its mechanisms. Methods:The bortezomib-resistant MM cell lines H929-R and primary cells from patients who do not respond to bortezomib were used asin vitro models. The inlfuences of bortezomib and/or forskolin on MM cells were evaluated through cellular morphology, changes of cell distribution and apoptotic rate. Meanwhile, lfow cytometry analysis was used to detect mitochondrial transmembrane potential (ΔΨm) and the expression levels of apoptosis regulators in these cells before and after the treatment were detected by Western blot.Results:Bortezomib (20 nmol/L) synergized with forskolin (50nmol/L) to induce apoptosis of H929-R cells and bortezomib-resistant primary cells. In addition, borte-zomib synergized with forskolin to induce collapse of mitochondrial transmembrane and facilitate the degradation of anti-apoptosis proteins including Bcl-2 and Mcl-1.Conclusion:Bortezomib could synergize with forskolin to induce apoptosis in bortezomib-resistant MM cells.

Objective: To understand the occupational hazard and distribution of silica dust (free SiO₂≥10%) in the workplace environment of the enterprises in Fengxian District, and to provide scientific basis for improving the working environment and protecting the physical and mental health of the workers. Methods: Individual sampling monitoring and on-site labor hygiene investigation were conducted on 421 workers involved in 87 silicon dust enterprises in the jurisdiction from 2014 to 2018, and measured concentration-time weighted average (C_TWA) . Results: The results showed that the range of the C_TWA was (0.021~17.000) mg/m³, the median was 1.600 mg/m³, and the qualified rate of 30.88%. The difference of total dust concentration was statistically significant in different years (Z=38.831, P<0.05) . The qualified rate of small-scale enterprises is higher than that of medium-scale enterprises (χ²=9.472, P<0.05) . The qualified rate of other domestic enterprises is higher than that of private enterprises and foreign enterprises (χ²=10.089, P<0.05) . The acceptance rate of metal products manufacturing is lower than that of general equipment manufacturing and other manufacturing enterprises (χ²=64.626, P<0.05) . The qualification rate of natural ventilation is higher than that of mechanical ventilation (χ²=6.278, P<0.05) . Conclusion The enterprises involved in silicon production in Fengxian District need to further strengthen the production process reform and improve the ventilation and dust removal protection measures. Widely carry out the publicity of occupational disease prevention and control law, conduct targeted pre-job training, improve workers' awareness of self-protection, and protect the occupational health of workers in many ways.