ABSTRACT
OBJECTIVE: To explore the stability of recombinant human serum albumin and interferon alpha 2b fusion protein for injection. METHODS: According to the testing methods of Ch.P, influencing factors test [high temperature test at (42±2)℃, strong light test at (4 500±500)lx and humidity test at RH of 90%], accelerated test (37 and 25 ℃)and long-term test were carried out according to the technical guidelines of biological stability study. RESULTS: The results of influencing factors test, accelerated test and long-term test showed that temperature had influence on the purity of products. The protein purity decreased with the increase of temperature. Humidity also had influence on the moisture content of products, with little influence on other indicators. Long term stability investigation found that the sample was relatively stable within 24 months and the examined indexes accorded with the quality standard. CONCLUSION: This recombinant protein can be stored at 2-8 ℃ for 24 months.
ABSTRACT
Objective To compare the clinical efficacy of posterior pedicle screw fixation through Wiltse paraspinal approach and posterior traditional open approach in the treatment of thoracolumbar fracture and dislocation.Methods A retrospective case control study was performed based on the clinical data of 40 patients with thoracolumbar fracture and dislocation admitted between January 2013 and January 2016.All the surgeries were performed through posterior midline incision,and they were divided into two groups according to different approaches.Patients in Group A received pedicle screw fixation through Wiltse paraspinal approach while Group B received fixed pedicle screw through open surgery.Group A was composed of 12 males and 8 females,aged 21-60 years [(41.5 ±9.6)years].Group B was composed of 13 males and 7 females,aged 18-58 years [(39.1 ± 13.1) years].The same surgical procedures were adopted in spinal decompression,reduction,and the spinal vertebral interbody bone graft and fusion surgery in the two groups.Operation duration,intraoperative blood loss,postoperative drainage volume,visual analogue scale (VAS),spinal canal patency at the last follow-up,percentage of postoperative injury of vertebral height recovery,and Cobb angle were compared.CT and MRI were used to evaluate postoperative paravertebral muscle atrophy,and American spinal injury association (ASIA) impairment scale was used to evaluate neurological function assessment.Results All patients were followed up for 9-33 months,with (19.3 ± 5.6) months for Group A and (22.5 ± 4.9) months for Group B (P ＞ 0.05).The operation duration was (240.5 ± 38.3) min in Group A and (258.5 ± 43.7) min in Group B (P ＞ 0.05).The intraoperative blood loss was (525.0 ± 168.2) ml in Group A,less than (770.0 ± 269.2) ml in Group B (P ＜ 0.05).Postoperative drainage volume was (190.1 ± 78.9) ml in Group A,less than (281.7 ± 122.3) ml in Group B (P ＜ 0.05).VAS score 24 hours after operation and at the last follow-up in Group A was (6.4 ± 1.0) points and (1.6 ± 0.5) points,respectively,better than those in Group B [(7.8 ± 0.7) points and (2.2 ± 0.4) points] (P ＜ 0.05).No significant differences were observed in terms of spinal canal patency at the last follow-up,percentage of postoperative injury of vertebral height recovery,and Cobb angle [Group A:(85.3 ± 3.7) ％,(85.5 ± 2.7) ％,and (4.7 ± 1.2)°;GroupB:(85.8±1.8)％,(88.8 ±1.3)％,and (5.3 ±1.5)°] (P＞0.05).In terms of MRI evaluation score of postoperative paravertebral muscle atrophy,Group A reported better results than Group B [(2.1 ± 0.6) points vs.(1.2 ± 0.6) points] (P ＜ 0.05).At the last follow-up,there were 7,5,6,1 and 1 patients in Group A,while 6,6,5,2 and 1 patients in Group B at ASIA grades A,B,C,D and E (P ＞ 0.05).Within the same group,significant difference was observed between the preoperative data and that at the last follow-up in terms of postoperative VAS score,spinal canal patency,percentage of injury of vertebral height,Cobb angle,and ASIA impairment scale (P ＜ 0.05).Conclusion For thoracolumbar fracture and dislocation,compared with traditional open approach,posterior pedicle screw fixation through Wiltse paraspinal approach can effectively restore the vertebral body height and spinal canal patency and can reduce the intraoperative bleeding,postoperative drainage,postoperative back pain,and paravertebral lesion.
ABSTRACT
Objective To construct four types of glucagon-like peptide-1 (GLP-1) and human serum albumin (HSA) fusion proteins that can be realeased at different rate in vivo by introducing protease cleavage sites between these two moieties.The therapeutic effect and release rate are studied to achieve balanced pharmacokinetics ( PK) and pharmacody-namics ( PD) of GLP-1 and HSA fusion proteins.Methods The gene with different polypeptide joint of GLP-1 and HSA fusion proteins were synthesized by overlap extension PCR amplification, cloned into expression vector pPIC9 and transformed into Pichia pastoris GS115.Then, fusion proteins were obtained by protein purification after being induced by methanol.The preliminary PK and PD of the fusion proteins were studied after purification.Results The fusion protein Gly2-GLP-1-GGGGG-HSA showed no release while Gly2-GLP-1-VTR-HSA, Gly2-GLP-1-SARSVRA-HSA, and Gly2-GLP-1-GRSRVTRSV-HSA showed a slow, medium and fast release rate, respectively, after incubation with furin.In vitro biological activity test results dispalyed that each type of fusion protein promoted insulin secretion of MIN6 cells.In vivo PK test indicated the half-life size of fusion proteins was the largest in Gly2-GLP-1-GGGGG-HSA, followed by Gly2-GLP-1-VTR-HSA, Gly2-GLP-1-SARSVRA-HSA, and Gly2-GLP-1-GRSRVTRSV-HSA.In vivo PD test exhibited hypoglycemic activity that was the highest in Gly2-GLP-1-VTR-HSA, followed by Gly2-GLP-1-SARSVRA-HSA, Gly2-GLP-1-GRSRVTRSV-HSA, and Gly2-GLP-1-GGGGG-HSA.Conclusion GLP-1 can be released from fusion proteins with full activity after the introduction of protease cleavage sites.Releasable fusion proteins at an appropriate release rate have the most balanced PK and PD.
ABSTRACT
OBJECTlVE To study the anti-HBV activity of prepared recombinant human serum aIbu-min-interferon α-2b fusion protein(HSA-IFNα-2b) in vitro. METHODS HepG2 ceIIs were infected with recombinant adenovirus with green fIuorescence protein and 1.6-foId HBV DNA(AdGFP-HBV). The ex-pression of HBV antigens,HBsAg and HBeAg in cuIture medium was detected by ELISA assay. The tox-icity of HSA-IFNα-2b on HepG2 ceIIs was evaIuated by mTT assay.The reIative expression of HBV RNA in ceIIs and the absoIute quantity of HBV DNA in cuIture supernatant were determined by quantitative PCR assay. The activity of HBV enhancer Ⅰ was detected by DuaI-Reporter gene assay. RESULTS HBV couId repIicate and express in HepG2 ceIIs after infection with AdGFP-HBV. The expression of HBsAg and HBeAg in cuIture serum of HepG2 ceIIs infected with AdGFP-HBV decreased by 51.32%(P﹤0.01)and 50.26%(P﹤0.01),respectiveIy,when HSA-IFNα-2b 500 kU·L-1 was added. The same concentration of HSA-IFNα-2b didn't inhibit the proIiferation of HepG2 ceIIs,but inhibited HBsAg in a concentration-dependent manner. The regression formuIa between HBsAg inhibitory rate(Y)and con-centration of HSA-IFNα-2b(X)was Y=21.11 IgX+11.91(r 2 = 0.954),IC50 = 63.76 kU·L-1 . HBV RNA in ceIIs and HBV DNA in the cuIture serum decreased by 52.83%(P﹤0.01)and 53.07%(P﹤0.01), respectiveIy,when HSA-IFNα-2b 500 kU·L-1 was added. The activity of enhancer Ⅰ decreased by 40.04%(P﹤0.01)when HSA-IFNα-2b 500 kU·L-1 was added. CONCLUSlON The ceII modeI of HBV repIication for evaIuating anti-HBV agents is successfuIIy estabIished. HSA-IFNα-2b exhibits noticeabIe anti-HBV effect invitro.