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Wang L.-C.,National Institutes of Food and Drug Control
Chinese Journal of Biologicals | Year: 2012

Objective: To dynamically monitor the stability of virulence of challenge strain, stored in liquid nitrogen, for determination of potency of pertussis vaccine. Methods: After B. pertussis seeds was resuscitated and subcultured for 3 passages, the bacterial lawns were collected, diluted by turbidimetry, distributed and stored in liquid nitrogen. The virulence of the B. pertussis strain was monitored dynamically every year from 2008-2010 by modified challenge test in mouse brain, of which the stability was evaluated. Results: No significant change was observed in the virulence of challenge strain of B. pertussis after storage in liquid nitrogen, idnicating high stability. Conclusion: The virulence of challenge strain of B. pertussis was stable after storage in liquid nitrogen, indicating that liquid nitrogen was suitable for storage of challenge strain of B. pertussis for potency test of pertusssis vaccine. Source


Chen M.-L.,Chinese PLA General Hospital | Miao L.,Chinese Academy of Sciences | Cao J.,National Institutes of Food and Drug Control | Ip S.-P.,Chinese University of Hong Kong | Che C.-T.,University of Illinois at Chicago
Journal of Separation Science | Year: 2012

Five Seeds Combo (Wu Zi Yan Zong Wan) is a traditional Chinese herbal formula composed of Fructus Lycii, Semen Cuscutae, Fructus Rubi, Semen Plantaginis, and Fructus Schisandrae. This herbal prescription has been developed into herbal products by many pharmaceutical manufacturers for treating age-related symptoms. The present study aims to develop an analytical method for the quality control of this herbal drug. Nine active ingredients including schisantherin A, schisandrin B, schisandrin, schisandrin A, quercitrin, betaine, verbascoside, hyperoside, and kaempferol were selected as the targeted analytes for the analysis. By using liquid chromatogram/quadrupole time-of-flight mass spectrometry (MS), the nine chemical compounds were determined simultaneously from the chromatogram. The parameters for MS were optimized by orthogonal array testing and the best condition of the MS for the determination of the nine marker compounds was found to be 175, 75, and 700 V for fragmentor, skimmer, and voltage of capillary, respectively. The method validation showed that this analytical method had high precision and sensitivity (limit of quantitation was smaller than 10 ng/mL for most of the analytes). The method was found to be able to demonstrate the quality of Five Seeds Combo from different manufacturers. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Guan J.,Peking Union Medical College | Tong W.,Peking Union Medical College | Ding W.,Dalian Medical University | Du S.,Peking Union Medical College | And 15 more authors.
Biomaterials | Year: 2012

It has been well confirmed that brain-derived neurotrophic factor (BDNF) has therapeutic effects following stroke. However, it is difficult to be maintained at a sufficient concentration of BDNF in the infarcted hemisphere. We have shown in our previous work that BDNF fused with a collagen-binding domain (CBD-BDNF) could specifically bind to collagen. The ventricular ependyma of the brain is rich in collagen. Therefore, we have speculated that in the infarcted hemisphere, CBD-BDNF will bind to the collagen of the ventricular ependyma and stimulate the cell proliferation in the subventricular zone (SVZ). Using a rat middle cerebral artery occlusion model (MCAO), we injected CBD-BDNF into the lateral ventricle of MCAO rats. The results demonstrated that CBD-BDNF was retained at high levels in the infarcted hemisphere, promoted neural regeneration and angiogenesis, reduced cell loss, decreased apoptosis, and improved functional recovery. In addition, brain perfusion and metabolism, as evaluated by SPECT and PET, were improved in the CBD-BDNF treated group. © 2011 Elsevier Ltd. Source


Yu Y.-Z.,Beijing Institute of Biotechnology | Guo J.-P.,Academy of Military Medical Science | Zhang S.-M.,National Institutes of Food and Drug Control | Wang S.,Beijing Institute of Biotechnology | And 2 more authors.
Vaccine | Year: 2013

Human botulism is commonly associated with botulinum neurotoxin (BoNT) serotypes A, B, E and F. This suggests that the greatest need is for a tetravalent vaccine that provides protection against all four of these serotypes. In current study, we investigated the feasibility of generating several tetravalent vaccines that protected mice against the four serotypes. Firstly, monovalent replicon vaccine against BoNT induced better antibody response and protection than that of corresponding conventional DNA vaccine. Secondly, dual-expression DNA replicon pSCARSE/FHc or replicon particle VRP-E/FHc vaccine was well resistant to the challenge of BoNT/E and BoNT/F mixture as a combination vaccine composed of two monovalent replicon vaccines. Finally, the dual-expression DNA replicon or replicon particle tetravalent vaccine could simultaneously and effectively neutralize and protect the four BoNT serotypes. Protection correlated directly with serum ELISA titers and neutralization antibody levels to BoNTs. Therefore, replicon-based DNA or particle might be effective vector to develop BoNT vaccines, which might be more desirable for use in clinical application than the conventional DNA vaccines. Our studies demonstrate the utility of combining dual-expression DNA replicon or replicon particle vaccines into multi-agent formulations as potent tetravalent vaccines for eliciting protective responses to four serotypes of BoNTs. © 2013 Elsevier Ltd. Source


Guan J.,Peking Union Medical College | Zhu Z.,Peking Union Medical College | Zhao R.C.,Peking Union Medical College | Xiao Z.,CAS Institute of Genetics and Developmental Biology | And 11 more authors.
Biomaterials | Year: 2013

Studies have suggested that mesenchymal stem cells (MSCs) have therapeutic effects following traumatic brain injury (TBI). However, cell distribution and survival rate are two major barriers to their success as therapeutic treatment. The improvement of cell therapy using collagen delivery matrices had been reported. However, we know very little about the mechanisms. We labeled human bone marrow-derived mesenchymal stem cells (hMSCs) with a positron emission tomography (PET) tracer, 18F-fluoro-2-deoxy-d-glucose (FDG). hMSCs were transplanted with or without collagen scaffolds into rats with experimental TBI and the whole-body nuclear images were compared. Collagen scaffolds increased the retention of hBMSC in the lesion site and limited its distribution at the transplanted region. Significantly more hMSCs were detected in the brain when transplanted with collagen scaffolds. The results showed collagen scaffolds also efficiently improved cell survival and neurite outgrowth invivo, resulting in better neural functional recovery. In addition, brain metabolism also improved in the collagen scaffold implanted group, as evaluated by PET. We speculated that collagen scaffolds would improve early engraftment and support the survival of grafted cells post-transplantation. © 2013 Elsevier Ltd. Source

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