Development of a mobile personnel radiation protection equipment / 中国辐射卫生

Objective To design a mobile personnel radiation protection equipment for operation in environments with high radiation such as spent fuel reprocessing plants, to achieve simultaneous protection against γ radiation, neutron radiation, and radioactive aerosol, to reduce the internal and external exposure dose of radioactive workers, and to meet the requirement of operation for two hours. Methods The core parts of the mobile personnel radiation protection equipment included a shielding chamber and a respiratory maintenance system. An automated chassis was used for the movement and lifting of the shielding chamber. MCNP software was used to simulate and calculate the protective effects of shielding chamber made of different materials and material thicknesses. Experimental verification of the shielding chamber design was conducted. Mathematical models were established to describe the variations in the content of various gases in the chamber with personnel operation time. A respiratory maintenance system, a harmful gas absorption device, and an automated mobile chassis were designed. Results The shielding chamber made of polyethylene with a thickness of 80 mm achieved an 80% neutron shielding rate. The respiratory maintenance system could support workers for 2 hours of operation inside the equipment. The mobile chassis allowed operation of the equipment with one person. Conclusion This mobile personnel radiation protection equipment can solve the problem in simultaneous protection against γ radiation, neutron radiation, and radioactive aerosol. The equipment can provide radiation protection for radioactive workers, reduce exposure dose, and reduce personnel burden. This system provides technical means for the operation and maintenance of equipment in high-radiation sites such as spent fuel reprocessing plants.

Investigation on the radiation of 131I in treatment site of a grade A tertiary hospital / 中国辐射卫生

Objective To detect the radiation of 131I in treatment site of a grade A tertiary hospital. Methods A total of 25 patients with thyroid cancer were administrated 131I at a total dose of 82880 MBq. After administration, the ambient dose equivalent rate of the ward was detected with X- and γ-ray detectors. After patient discharge, surface contamination of the ward was detected with α/β surface contamination meter. During patient hospitalization and on the day of discharge, air samples were collected from 131I treatment site and office area. The air samples were measured using a HPGe γ-ray spectrometer and the concentration of 131I in air was calculated. Results The ambient dose equivalent rate in the ward ranged from 0.15 to 0.46 μSv/h. Before ward cleaning, surface contamination ranged from 0.53 to 40.1 Bq/cm2 and the highest value was recorded on the toilet. Within 4 h after administration, the concentrations of 131I in air in treatment site and the corridor of the office area were 1.74 Bq/m3 and 0.66 Bq/m3, respectively. The ventilation air flow rate in the treatment site was 0.50 m/s. Ventilation decreased the concentration of 131I in air by 29.7%, 79.7%, and 53.3% compared with the previous day during hospitalization and on the day of discharge. Conclusion The radiation of external exposure of 131I in the treatment site is low and the shielding is effective. Before ward cleaning, the surface contamination is lower than the required limits except for the toilet. Ventilation is the primary way to reduce the concentration of 131I in air.

Activity variation and dose level in patient′s body with differentiated thyroid cancer after 131I therapy / 中华放射医学与防护杂志

Objective:To study the variation in activity in patient′s body with differentiated thyroid cancer (DTC) treated with 131I and external dose level, analyze the relationship between the both, and estimate the correction factor for the dose equivalent rate for the patients with residual activity of 400 MBq. Methods:A total of 43 DTC patients who received 131I therapy for the first time after total thyroidectomy were studied. The dose was 1 850-3 700 MBq and average dose was (2 405±777) MBq. The measurements of residual activity in patient′s body and of dose equivalent rate at 0.3, 1 and 3 m in front of the patients were performed at 2, 6, 20, 22, 24, 27, 30, 44, 46, 48, 54, 68 and 72 h after administration of 131I. Results:The residual activity in patient′s body after 131I therapy varied with time as a function of A= A0 (1.033 16e -0.062 4t+ 0.017 17). It can be estimated that the effective half-life of DTC patients treated with thyroid remnant 131I ablation therapy is 12.19 h. It needs only 26.4-38.9 h to reduce the internal activity to the 400 MBq. The functions of variation with time of normalized dose equivalent rate at 0.3, 1, and 3 m away from patients were: H· 0.3=127.220 7e -0.054 8t+ 3.765 71; H· 1=30.225 8e -0.064 4t+ 0.824 67; and H· 3=4.161 9e -0.061 5t+ 0.167 97, respectively. There was a positive correlation between residual activity and dose equivalent rate at 1 m ( r=0.982, P<0.05), and the function is H· 1=0.025 A+ 1.245. When residual activities in DTC patient′s body were 1 000, 700 and 400 MBq, the corresponding dose equivalent rates at 1 m from patients were 26.2, 18.7 and 11.2 μSv/h, respectively. The correction factors for dose equivalent rate at 0.3, 1 and 3 m from patients with 400 MBq were 0.25, 0.49 and 0.70, respectively. Conclusions:DTC patients with administration of 131I activity below 3 700 MBq need only to be hospitalized for two days to reach the discharge standards. When the residual activity in DTC patient′s body drops to 400 MBq, the dose equivalent rate at 1 m is far less than 25 μSv/h. Simply using the point source formula to estimate the dose equivalent rate around the patient will result in overestimation. Therefore, the correction factor used in the estimation of radiation doses to patients by using the formula needs to be further studied so as to make the model-based estimated result more consistent with the actual situation.

Inhibitory effects of Bupleurum chinense-Scutellaria baicalensisdecoction on activation of rat HSC induced by CCl4 / 中国药理学通报

Aim To investigate the inhibitory effect of Bupleurum chinense-Scutellaria baicalensis decoction(CQ)on activation of rat HSC induced by CCl4 and the mechanism.Methods Cells in logarithmic growth phase were cultured in culture medium without FBS for 24 h.After disassociated using 0.25％EDTA-trypsin,the cells were seeded into respective plates at the density of 1.5×109· L-1 and cultured overnight.The cells were divided into the following groups:control group(no treatment),model group(treated with 6 mmol·L-1 CCl4 for 24 h),CQ groups(pretreated with 6 mmol·L-1 CCl4 for 24 h and 400,500,600 mg·L-1 CQ for 24 h).Concentrations of hyaluronidase(HA),laminin(LN),procollagen Ⅲ(PCⅢ),collagen type Ⅳ(Ⅳ-C)were assayed by ELISA kits.Gene expressions of Toll-like receptor 4(TLR4)and NF-κB were examined by RT-PCR analysis.Protein expression of TLR4 and NF-κB was examined by Western blot.Results CQ could significantly inhibit cell proliferation induced by CCl4.Furthermore,CQ at 600 mg·L-1 significantly downregulated gene and protein expressions of TLR4 and NF-κB.And CQ reduced the secretion of HA,LN,PCⅢ,Ⅳ-C.Further studies disclosed that the TLR4 inhibitor TAK-242 and NF-κB inhibitor BAY 11-7082 could significantly inhibit the gene and protein expressions of NF-κB,but could not change gene and protein expression of TLR4,and reduced the secretion of HA,LN,PCⅢ,Ⅳ-C.Conclusion CQ could inhibit inflammatory responses in HSC induced by CCl4 probably by inhibiting the transcription activity and protein expression of TLR4-NF-κB,which indicates its possible therapeutic effect on liver fibrosis.

Generation of Japanese Encephalitis Virus-like Particle Vaccine and Preliminary Evaluation of Its Protective Efficiency / 病毒学报

The cDNA fragment of JEV prME gene was cloned into the baculovirus shuttle vector (bacmid) to construct a recombinant baculovirus vector, defined as AcBac-prME. Then the recombinant baculovirus Ac-prME was obtained by transfecting Sf9 cells with AcBac-prME. Western blot analysis and immunofluorescence results indicated that both prM and E proteins were efficiently expressed in Sf9 cells. Electron microscopy suggested that prME was assembled into JEV-VLPs. To further evaluate the potential of JEV-VLPs as vaccine, the mice were immunized with JEV-VLPs and then challenged with lethal JEV. The results of mice survival and pathological changes demonstrated that the JEV-VLPs performed complete protection against JEV-P3 strain and relieved pathological changes in the mice brain significant. This study suggest that JEV-VLPs would be a potential vaccine for Japanese encephalitis virus.

The nucleoprotein of severe fever with thrombocytopenia syndrome virus processes a stable hexameric ring to facilitate RNA encapsidation

Severe fever with thrombocytopenia syndrome virus (SFTSV), a member of the Phlebovirus genus from the Bunyaviridae family endemic to China, is the causative agent of life-threatening severe fever with thrombocytopenia syndrome (SFTS), which features high fever and hemorrhage. Similar to other negative-sense RNA viruses, SFTSV encodes a nucleocapsid protein (NP) that is essential for viral replication. NP facilitates viral RNA encapsidation and is responsible for the formation of ribonucleoprotein complex. However, recent studies have indicated that NP from Phlebovirus members behaves in inhomogeneous oligomerization states. In the present study, we report the crystal structure of SFTSV NP at 2.8 Å resolution and demonstrate the mechanism by which it processes a ringshaped hexameric form to accomplish RNA encapsidation. Key residues essential for oligomerization are identified through mutational analysis and identified to have a significant impact on RNA binding, which suggests that correct formation of highly ordered oligomers is a critical step in RNA encapsidation. The findings of this work provide new insights into the discovery of new antiviral reagents for Phlebovirus infection.

Genetic Modification of Baculovirus Expression Vectors / 中国病毒学·英文版

As a protein expression vector,the baculovirus demonstrates many advantages over other vectors.With the development of biotechnology,baculoviral vectors have been genetically modified to facilitate high level expression of heterologous proteins in both insect and mammalian cells.These modifications include utilization of different promoters and signal peptides,deletion or replacement of viral genes for increasing protein secretion,integration of polycistronic expression cassette for producing protein complexes,and baculovirus pseudotyping,promoter accommodation or surface display for enhancing mammalian cell targeting gene delivery.This review summarizes the development and the current state of art of the baculovirus expression system.Further development of baculovirus expression systems will make them even more feasible and accessible for advanced applications.

Developments of Subunit and VLP Vaccines Against Influenza A Virus / 中国病毒学·英文版

Influenza virus is a continuous and severe global threat to mankind.The continuously re-emerging disease gives rise to thousands of deaths and enormous economic losses each year,which emphasizes the urgency and necessity to develop high-quality influenza vaccines in a safer,more efficient and economic way.The influenza subunit and VLP vaccines,taking the advantage of recombinant DNA technologies and expression system platforms,can be produced in such an ideal way.This review summarized the recent advancements in the research and development of influenza subunit and VLP vaccines based on the recombinant expression of hemagglutinin antigen (HA),neuraminidase antigen (NA),Matrix 2 protein (M2) and nucleocapsid protein (NP).It would help to get insight into the current stage of influenza vaccines,and suggest the future design and development of novel influenza vaccines.

Serial Expression of the Truncated Fragments of the Nucleocapsid Protein of CCHFV and Identification of the Epitope Region / 中国病毒学·英文版

The Crimean-congo hemorrhagic fever virus(CCHFV)is a geographically widespread fatal pathogen.Identification of the epitope regions of the virus is important for the diagnosis and epidemiological studies of CCHFV infections.In this study,expression vectors carrying series truncated fragments of the NP(nueleoeapsid protein)gene from the S fragment of CCHFV strain YL04057 were constructed.The recombinant proteins were expressed in E.coli and purified for detection.The antigenic of the truncated fragments of NP was detected with a polyclonai serum(rabbit)and 2 monoclonal(mAbs)(14B7 and 43E5)against CCHFV by Western-blot analyses.The results showed that the three expressed constructs,which all contained the region 235AA to 305AA could be detected by mAbs polyclonal serum.The results suggest that region 235-305 aa of NP is a highly antigenic region and is highly conserved in the NP protein.

Optimize conditions and activities for neutrophil lipase immobilized by nano-silica dioxide / 生物工程学报

We used adsorption method to immobilize the lipase by using nano-silica dioxide as the carrier. And we also studied different immobilization conditions effects on the catalytic activity. We got optimize immobilization conditions which were as follow the lipase quantity of 28,300 U/g, temperature of 45 degrees C, pH of 7.5 and treated for 10 h. Under these conditions the immobilized lipase activity yield 3867 U/g carrier. The best reactive temperature for immobilized lipase was 45 degrees C and higher than 5 degrees C for free enzyme, and the optimal pH dropped to 5.5 compared that of free enzyme (pH 7.0). The immobilized lipase stability for thermal and pH are improved than free lipase. When temperature was below 70 degrees C the immobilized enzyme activity was over 70% than initial activity. The free lipase activity just kept original 30% at 50 degrees C. When pH was 5-8, the immobilized lipase activity was still more than 50% and the free lipase only remained 20%. When we used the immobilized neutrophil lipase catalyzing different oil to produce biodiesel such as soybean oil, rapeseed oil and waste oil, the esterification rate of rapeseed oil was the highest.

Virion Proteomics of Large DNA Viruses / 中国病毒学·英文版

Large DNA viruses normally have complex structures with many of protein components derived from both viral and host origins. The development in proteomics, especially mass spectrometry identification techniques provide powerful tools for analyzing large viruses. In this review, we have summarized the recent achievements on proteomic studies of large DNA viruses, such as herpesvirus, poxvirus, nimavirus and baculoviruse. The proteomics of baculovirus occlusion-derived virions (ODV) were emphasized. Different mass spectrometry techniques used on ,carious baculoviruses were introduced, and the identified structurally associated proteins of baculoviruses are summarized.

Evaluation of Sensitivities and Specificities of SARS-CoV Detection by Real-time Quantitative Reverse Transcription-PCR Assays / 中国病毒学·英文版

The etiological agent of severe acute respiratory syndrome (SARS) was identified as a new coronavirus, termed SARS-CoV. Establishment of an efficient and sensitive diagnostic system of SARS-CoV genetic materials is crucial for SARS control. In this study, we quantified SARS-CoV mRNAs in both infected cell culture lysate and in supernatant by using Real-time quantitative revere transcription-PCR based on EvaGreen鈩?dye and Taqman-MGB probes. For extensive evaluation of sensitivities and specificities, 13 pairs of primers and 4 probes were designed based on different genes of SARS-CoV. Glyceraldehydes-3-phosphate dehydrogenase (GAPDH) was selected as the internal control gene. Results showed that S-gene-specific PCR was the most sensitive for detection, but because of its sequence variability in the different viral strains, primers and a probe based on the N gene were suitable substitutions. Meanwhile, we found the mRNA concentrations in cell culture lysates were much higher than in cell supernatant and facilited more sensitive detection of the SARS-CoV.

Study on hydrophilicity and degradability of polyvinyl alcohol/polylactic acid blend film / 生物医学工程学杂志

Based on casting and solvent evaporation method, the degradable PLA/PVA blend film was prepared with polylactic acid (PLA) and polyvinyl alcohol (PVA) as raw material. The moisture absorbability, water absorbability and degradability of the polylactic acid/polyvinyl alcohol (PLA/PVA) blend film were studied; also the degradation mechanism of blend film was investigated. The results showed that the moisture absorption and water absorption of blend film decreased as the concentration of PLA increased. The degradation process of blend film in the normal saline is conducted by stepwise. At the forepart, the degradation of PLA played an important role, while PVA was the main degradation substance later. The solvent acidity could catalyze the degradation of PLA, and degradation of PLA was always turning from noncrystalline region to crystalline region. PVA had abilities to accelerate the degradation of PLA by increasing the hydrophilicity of the blend film and by breaking the crystallinity of PLA. Therefore, the hydrophilicity and degradability of PLA/PVA blend film can be controlled in a certain range by adjusting the proportion of PLA and PVA.

An Improved Culture System for Virus Isolation and Detection / 中国病毒学·英文版

Cell culture plays an important role in virology. It provides a platform for the detection and isolation of viruses as well as for the biochemistry and molecular biology based studies of viruses. In the present work, a new system that could permits multiple (different) cell lines to be simultaneously cultured in one dish was developed. In the system, each cell line was cultured in an isolated zone in the same dish or well and the system is therefore called an isolated co-culture system. The usefulness of this novel approach for virus isolation was demonstrated using a model system based on adenovirus.