ABSTRACT
Objective To investigate the thawing modes on stability of coagulation control products after frozen,looking for a new theoretical basis for cost control and the quality and safety of laboratory.Methods Using ACL TOP 700 automated co-agulation analyzer and supporting the same batch of reagents and quality control materials conduct of the study:after daily QC,recycled the remaining control materials immediately and dispensed into two EP tubes and frozen at-40℃,respectively thawed by room-temperature and 37℃water bath after 24 hours,and examined together with the date of quality control ma-terial,got 20 pairs of data for analysis the financial impact of two alternate ways on coagulation QC parameters.Results For the room-temperature thawing group,FIB high value increasedby an average 0.23 g/L (t=4.026 9,P0.05).For the 37℃water bath group,both normal and high value of APTT,PT,FIB,TT and D-Dimer were no significant difference after tha-wing (P>0.05).Conclusion The commercialization of coagulation control materials can be for the second QC,just follow the principle of rapid after melting and timely detection,other laboratories can be used as a reference.
ABSTRACT
Objective: To explore the application of high hydrostatic pressure in the development of melanoma vaccine.Methods:The high hydrostatic pressure,liquid nitrogen freezing and thawing were used to break the murine B16 melanoma cells and then the cell suspension was mixed with Freund's adjuvant to prepare vaccine for immunizing the mice.Results:After immu-nization,the murine B16 melanoma cells were injected intravenously and subcutaneously.The immune results of the vaccines were evaluated,by comparing survival time of the mice, subcutaneous tumor volume, DTH experiments and the fluorescence imaging of tumors.Conclusion:Compared with the method of liquid nitrogen freeze-thaw broken,high hydrostatic pressure crushing cells has more advantages in the development of tumor vaccine.
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Objective To achieve the fusion expression of the entire human beta-defensin-3(hBD-3) gene. Method We synthesized two oligonucleotide primers accor ding to the codon preference of Escherichia coli. The gene was cloned into p GEX -4T-2 to establish the pGEX-4T-2-hBD-3 as the fusion expression vector by PCR. Transformed into E.coli strain DH5α, the express vector was induced an d ex pressed by IPTG. The fusion protein GST-hBD-3 was obtained by repeated cycles of freezing and thawing, cut by thrombin to attain the recombinant hBD-3 protei n. Result The result of the antibacterial peptide agarose diffu sion assay shows the antibacterial activity of the rhBD-3 against the S.aureu s exists, and it reaches 0.843U. Conclusion The fusion expr ession of the hBD-3 gene is successful.
ABSTRACT
The recent development of molecular diagnostic assays like as polymerase chain reaction (PCR) has provided powerful tools for the diagnosis of viral infection in the clinical fields. To ensure optimal therapeutic and prognostic value, it is important to establish whether viral load measurements are affected by repeated freeze-thaw (FT) cycles since the freezing of clinical samples is a universal method of specimen storage. This study was done to determine the effect of freezing and thawing of various samples on the quantitation and positivity of viral DNA. For this study, three different types of samples being used frequently in clinical fields were selected. Those samples contained ovine herpesvirus-2 (OvHV-2), a member of the gamma herpesviruses (genus Rhadinovirus). Two OvHV-2 DNA positive plasma samples, two peripheral blood mononuclear cell (PBMC) samples, and two nasal swab samples were randomly selected. They were carefully aliquated into 8 tubes for each sample. The aliquoted samples were frozen and thawed 0, 3, 6, 9, 12, 15, 18, and 21 times for each aliquot and then analyzed for changes on DNA levels and positivity. OvHV-2 DNA positivity and quantitation were tested by using nested PCR and real-time PCR, respectively. Twenty-one cycles of freezing and thawing did not significantly change this herpesviral DNA positivity in any of the samples tested. However, the decreases of viral DNA copies were observed in all samples by the increasing of FT cycles. In conclusion, the integrity of herpesviral DNAs in clinical specimens may be degraded by the increasing FT cycles. These results implicate that there is a need to aliquot specimen when it is first collected in order to reduce FT cycles during its analysis.