The bioactivity of a working reference standard was determined by replicate bioassays with calibration against a primary reference standard. In this study the number of bioassay replicates needed for calibration first was calculated theoretically, and if the mean value of the experimental bioassay replicates fell within the predefined bioactivity level the bioactivity of the working reference was defined as 100%. Our results showed that when the total intermediate precision of the bioassay method was at 11.66% and the predefined bioactivity level was set at 95%-105% with a confidence level of 95%, 21 bioassay replicates should be carried out for calibration. The average value of the 22 experimental bioassay replicates was 101.96%, so the bioactivity of the working reference standard was consistent with that of the primary reference standard at 100%. The results suggest that a strategy of first calculating the number of bioassay replicates needed for calibration and then determining whether the resulting experimental mean value is within the predefined bioactivity level will be of value to the biopharmaceutical industry.

The high performance liquid chromatography-fluorescence micelle assay (HPLC-FMA) method for the content determination of polysorbate 80 in monoclonal antibody drugs was validated to study its applicability and transferability between various laboratories, and the feasibility to be included in the Chinese Pharmacopoeia. Both J.T. Baker and Nanjing Well-sourced polysorbate 80 was used in the collaborative validation of polysorbate 80 content analysis in seven different laboratories. The results show that when the protein concentration was no more than 20 mg·mL^-1 and the concentration of polysorbate 80 ranged from 0.05 to 0.5 mg·mL^-1, the method had good specificity. The recovery rates of the spiked samples ranged from 92.20% to 117.70% for J.T.Baker and from 93.90% to 117.20% for Nanjing Well. The intra-laboratory precision (%RSD) was less than 4.30% for J.T. Baker, and less than 2.60% for Nanjing Well, while the overall precision was less than 5.45% for J.T. Baker, and less than 6.70% for Nanjing Well. The linear correlation coefficient was more than 0.98 for J.T. Baker and more than 0.99 for Nanjing Well. The results of the collaborative validation prove that the HPLC-FMA method has good accuracy, precision, linearity, and specificity, and could be used for release control analysis of polysorbate 80 content in monoclonal antibodies across different laboratories.

Objective To explore the feasibility of culturing dermal papillae cells (DPC) of hu- man hair in a serum-flee medium,and to observe the growth characteristics of these cells.Methods Cell culture flasks (plates) were pretreated with fibronectin,and DPC (2nd passage) were incubated with Williams E serum-flee medium supplemented with insulin-transferrin-selenite (ITS).Cells were observed by an inverted phase-contrast microscope.Proliferation of DPC was evaluated with 3-(4,5-dimethylthia- zol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and by their growth curve.Results In a serum-free medium,2nd passage DPC adhered to the flask surface within two to four hours of incubation; two to three days later,confluence,of the cells was observed,without noticeable proliferation.Four days later,cell connection was interrupted,isolated cells or cell clusters were seen,and detachment of some cells from the flask surface was observed.One to two weeks later,most cells had died.After incubation with 4% bovine serum for ten hours,cell proliferation was observed surrounding the remaining viable cell colonies. DPC growth curve showed stagnant phase and slow growth phase;however,log growth phase was not ob- served.Conclusion DPC could be successfully cultured in serum-free medium.However,the culture con- dition needs to be further optimized.

Aim:To construct the short hairpin small interfering RNA(shRNA) eukaryotic expression vector specific to mouse lectin like oxidized low density lipoprotein receptor 1(LOX-1) gene and to observe its silencing effect on LOX-1 in RAW264.7 cells.Methods:(1)The pLOX-1-shRNA expression vector was constructed by gene recombination,Then transfected into the cultured RAW264.7 cells.At 48 h after Transfection,the expression of LOX-1 mRNA in RAW264.7 cells were determined by semi-quantitative RT-PCR,the expression of LOX-1 proteins examined by Western blot.(2) Oil Red O Dyeing experiment was used to show the cellular lipid droplets in lipid-loaded cells.The method of cholesterol oxidase analysis was performed to determine the content of cellular cholesterol.The ability of uptake Dil-ox-LDL in RAW264.7 cells was assayed by fluorescence microscopy.Results: pLOX-1-shRNA expression vector was successfully constructed.Transfection of pLOX-1-shRNA expression vector into RAW264.7 cells down regulaled the expression level of LOX-1 gene,as compared with the control group,transfection of the RAW264.7 cells with LOX 1-shRNA led to a remarkable reduction of the number macrophages transformed into foam cell,and could suppress the uptake of ox-LDL.Conclusion:The pLOX-1-shRNA expression vector can inhibit the expression of LOX 1 in RAW264.7 cells and the transformation of the macrophages into foam,which may he beneficial in searching new gene therapy of atherosclerosis.

The in vitro transcribed (IVT) mRNA technology has progressed rapidly and the application of mRNA vaccines in the COVID-19 pandemic made it become the most talked-about topic. Compared with protein drugs, IVT mRNA has a lower cost; it can be modular produced and its sequence can be modified easily, so it has a broad application prospect. However, due to its short history, mRNA drugs face the problem of lacking sufficient clinical data, and there is no quality control standard for mRNA drugs except mRNA vaccines. We overview the sequence design, delivery vectors, administration, application prospect and safety considerations of mRNA drugs. We also discussed the quality control of mRNA drugs briefly.

The biological activity of ADCC by anti-CD20 monoclonal antibody was determined by BioGlo™ Luciferase Assay System using Jurkat/NFAT-luc+FcγRIIIa cell line as effector cell and WIL2-S cell line as target cell. The developed method was verified for specificity, precision and accuracy. Anti-CD20 monoclonal antibody showed a dose-response mode by the developed method, and the determination result complied with the following four-parameter equation: y = (A-D)/[1 + (X/C)(B)] + D. The optimized parameters of the method were determined including the antibodies diluted concentration (18,000 ng·mL(-1)), dilution rate (1:5), the ratio of effector cell and target cell (6:1), and induction time (6 h). The values of eight independent tests have passed a statistical test for curve regression analysis, linear or parallelism, which showed the method possessed good specificity. Four different dilute groups of recovery rates sample were determined for 3 times, and the result showed mean relative potencies of (44.39±3.93)%, (72.74±2.78)%, (128.28±7.01)% and (168.19±2.70)% respectively, with a variation coefficient of less than 10%, and the recoveries of (88.78±7.85)%, (96.99±3.70)%, (102.63±5.61)% and (112.12±1.80)% respectively. A novel reporter gene method for determination of biological activity of ADCC by anti-CD20 monoclonal antibody was successfully developed, which showed strong specificity, good reproducibility and high accuracy, and might be used routinely.
Antibodies, Monoclonal, Murine-Derived ; pharmacology ; Antibody-Dependent Cell Cytotoxicity ; Antigens, CD20 ; immunology ; Genes, Reporter ; Humans ; Reproducibility of Results ; Rituximab

This paper reports the determination of the drug antibody ratio in an antibody-drug conjugate with two methods, i.e. LC-MS and UV/VIS, and to provide a reliable method to scientifically evaluate and effectively control the drug antibody ratio. Deglycosylated sample was analyzed with C4 column followed by MS, and the number of conjugated drugs in the antibody was determined by the molecular weight increase due to the addition of different number of drugs to the antibody, and then drug antibody ratio was calculated by weighted average of different number of drugs conjugated to the antibody. Optical density at 252 and 280 nm was measured with UV/VIS, and due to the difference of extinction coefficients between the antibody and the drug, the drug antibody ratio was calculated from linear equation with two unknowns. The drug antibody ratio was 3.21 and 3.25 respectively measured by the two methods, and the results were similar with the two methods. Our study indicated that both methods, LC-MS and UV/VIS, could be applied to the analysis of drug antibody ratio of the antibody drug conjugate.
Antibodies ; analysis ; chemistry ; Gas Chromatography-Mass Spectrometry ; methods ; Glycosylation ; Immunoconjugates ; analysis ; chemistry ; Maleimides ; analysis ; chemistry ; Molecular Weight ; Pharmaceutical Preparations ; analysis ; chemistry ; Spectrophotometry, Ultraviolet ; methods

BACKGROUNDVarious tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells (NSCs) could survive in poly(L-lactic-co-glycolic acid) (PLGA) scaffolds and, when cografted with Schwann cells (SCs), could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function.

METHODSNSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student's t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance (ANOVA) was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials (CMEPs) and Basso, Beattie & Bresnahan locomotor rating scale (BBB) score. The χ(2) test was used to determine the differences in recovery percentage of CMEPs.

RESULTSNSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs ((1.7831 ± 0.0402)% vs. (1.4911 ± 0.0313)%, P < 0.001). Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA + NSCs + SCs group was more than that in PLGA + NSCs group and in PLGA group ((110.25 ± 30.46) vs. (18.25 ± 3.30) and (11.25 ± 5.54), P < 0.01). The percentage of CMEPs recovery in PLGA + NSCs + SCs group was higher than in the other groups (84.8% vs. 50.0% and 37.5%, P < 0.05). The amplitude of CMEPs in PLGA + NSCs + SCs group was higher than in the other groups ((1452.63 ± 331.70) µV vs. (428.84 ± 193.01) µV and (117.33 ± 14.40) µV, P < 0.05). Ipsilateral retransection resulted in disappearance again and functional loss of CMEPs for a few days. But contralateral retransection completely damaged the bilateral motor function.

CONCLUSIONSNSCs can survive in PLGA scaffolds, and SCs promote NSCs to survive and differentiate towards neurons in vivo which even might form synaptic connection. The scaffolds seeded with cells facilitate axonal regeneration and myelination and motor function recovery. But regenerating axons have limited contribution to motor function recovery.

Animals ; Axons ; physiology ; Cells, Cultured ; Electrophysiology ; Female ; Fluorescent Antibody Technique ; Lactic Acid ; chemistry ; Nerve Regeneration ; physiology ; Neural Stem Cells ; cytology ; Polyglycolic Acid ; chemistry ; Pregnancy ; Rats ; Rats, Wistar ; Schwann Cells ; cytology ; Spinal Cord Injuries ; therapy ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry

Objective To analyze the high risk factors of obstetric brachial plexus palsy(OBPP),and to explore how to evaluate the relationship between fault medical behavior and OBPP in the process of medical damage forensic identification.Methods A retrospective analysis was carried out on 25 cases of medical damage liability disputes related to OBPP from 2017 to 2021 in Beijing Fayuan Judicial Science Evidence Appraisal Center.The shortcomings of hospitals in birth weight assessment,delivery mode selection,labor process observation and shoulder dystocia management,and the causal relation-ship between them and the damage consequences of the children were summarized.Results Fault medi-cal behavior was assessed as the primary cause in 2 cases,equal cause in 10 cases,secondary cause in 8 cases,minor cause in 1 case,no causal relationship in 1 case,and unclear causal force in 3 cases.Conclusion In the process of forensic identification of OBPP,whether medical behaviors fulfill diagno-sis and treatment obligations should be objectively analyzed from the aspects of prenatal evaluation,de-livery mode notification,standardized use of oxytocin,standard operation of shoulder dystocia,etc.Meanwhile,it is necessary to fully consider the objective risk of different risk factors and the diffi-culty of injury prevention,and comprehensively evaluate the causal force of fault medical behavior in the damage consequences.

OBJECTIVETo investigate the associations of polymorphisms of metabolic enzyme genes with urinary 1-hydroxypyrene levels in coke oven workers.

METHODSOne hundred and forty-eight workers from a coke oven plant and 69 controls without occupational PAHs exposure were selected in this study. Urinary 1-hydroxypyrene was detected by high performance liquid chromatography with florescence detector. The genotypes at I462V site in exon 7 of CYP1A1 gene, GSTM1, GSTT1, I105V site in GSTP1gene, Pst1 and Dra1 sites in CYP2E1 gene, P187S site in NQO1 gene, Kpn1, BamH1 and Taq1 sites in NAT2 gene, and H113Y, R139H sites in mEH gene were determined by PCR-based methods. Personal information including occupational exposure history, age, sex, smoking and drinking status was collected by the questionnaire.

RESULTSThe level of urinary 1-hydroxypyrene in coke oven workers [(5.61 +/- 1.04) mol/mol Cr] was higher than that in control [(0.74 +/- 0.32) micro mol/mol Cr]. After adjusting external occupational exposure category and smoking, coke oven workers with variant homozygotes at H113Y site of mEH gene had significantly higher urinary 1-hydroxypyrene concentrations than those with heterozygotes, and wild homozygotes (6.41 +/- 1.09 vs. 6.24 +/- 1.08, and 4.62 +/- 0.95 micro mol/mol Cr, P < 0.05), and gene-gene interaction was found between CYP1A1 and mEH.

CONCLUSIONGenetic polymorphism of mEH gene could be a susceptible biomarker in coke oven workers which was involved in the individual susceptibility on metabolism of PAHs.

Coke ; adverse effects ; Cytochrome P-450 CYP1A1 ; genetics ; DNA Damage ; genetics ; Epoxide Hydrolases ; genetics ; Genetic Predisposition to Disease ; genetics ; Glutathione Transferase ; genetics ; Humans ; Male ; Occupational Exposure ; Polycyclic Aromatic Hydrocarbons ; poisoning ; Polymorphism, Genetic ; Pyrenes ; analysis ; metabolism