Development of a micro-circumstance airtight cabin for bioaerosol testing / 军事医学

Objective To develop a micro-circumstance airtight cabin for in the study of biological aerosols detection with such functions as airflow control and temperature and humidity detection .Methods Wind speed sensors , temperature and humidity sensors , electrical control valves , high efficiency filters and the vacuum pump formed the micro-circumstance regulating system .The techniques of airflow direction control , temperature compensation , air pressure control and aerosol uniformity distribution were used .Numerical simulation of aerosol concentration distribution in the airtight cabin was achieved using Fluent software .The bioaerosol concentration in different locations was tested by experiments .Results The micro-circumstance airtight cabin consisted of an airtight cabin and a control cabin .The control cabin used a single-chip microprocessor to provide air supply and exhaust air to the airtight cabin in a seaparate exhaust mode and cyclic ventilation mode.It worked under a negative pressure condition .Through numerical simulation,the aerosols were distributed through-out the cabin after five minutes of generation and the bottom airflow arrived at the top .The distribution of aerosol concentra-tion was approximately uniform .Conclusion The micro-circumstance airtight cabin is suited to various bioaerosols testing research thanks to its negative pressure working without bioaerosol leakage .

Environmental safety threshold of commonly encountered highly pathogenic microor-ganisms / 军事医学

Objective To study environmental safety reference standard values of commonly encountered pathogenic microorganisms, and provide the basis for environmental risk assessment of a high-level biosafety laboratory (BSL).Methods Using human exposure dose calculation methods as the basic principle in combination with microbial hazard evaluation methods , an infectious dose calculation model of human exposure to pathogenic microorganisms by breathing was proposed . Based on research on characteristics of commonly encountered pathogenic microorganisms at home and abroad , the environ-mental safety threshold reference standard and environmental risk protection zone for such microorganisms were obtained . Results An the environmental risk assessment standard calculation method for commonly encountered highly pathogenic microorganisms was proposed , and the minimum infectious dose and environmental safety threshold of seven commonly encountered pathogenic microorganisms were obtained , including SARS coronavirus , highly pathogenic avian influenza virus, Mycobacterium tuberculosis, Bacillus anthracis, Yersinia pestis,Francisella tularensis, and epidemic hemorrhagic fever virus.Conclusion The results can be used as a reference standard of infectious aerosols in a high-level BSL for environ-mental risk assessment , laboratory risk control and emergency management .

Research of immunogenicity of mycobacteriophage D29 toward tuberculosis therapy / 中华传染病杂志

Objective To investigate the immunogenicity of mycobacteriophage D29 (phage D 29) in guinea pig models with different delivery routes,and provide information for the application of phages in tuberculosis (TB) therapy.Methods Hartley guinea pigs were administrated with phage D29 through inhalation,intranasal drop or subcutaneous injection for 6 times within 35 days.7H9 broth aerosol inhalation and 0.85 ％ NaCl solution aerosol inhalation were set as solvent and negative controls,respectively.Anti-phage D29 neutralizing antibodies in sera collected weekly were measured by phage reduction neutralizing test (PRNT) and cytokine levels (interleukin-2,interleukin-4 and interferon-γ) were detected at day 35 by enzyme linked immunosorbent assay (ELISA).The data were analyzed by ANOVA and nonparametric test.ResultsNeutralizing antibodies were both negative in two control groups,while low-titer neutralizing antibodies (below 1 ∶ 100) appeared in inhalation and intranasal drop groups only at day 7 and day 14. Nevertheless, neutralizing antibodies were continuously detected in subcutaneous injection group,which increased rapidly and reached 1∶ 16 365.6 at day 35. After 35 days of experiments,serum concentrations of interleukin-2 (x2 =2.7605,P＞0.05),interleukin-4 (F=2.17,P＞0.05) and interferon-γ(F=0.75,P＞0.05) among three treatment groups and two control groups were all not significantly different.ConclusionsThe titer of anti-phage 29 neutralizing antibodies induced by inhalation or intranasal drop administration of phage D29 are both significantly lower than subcutaneous injection.Phage D29 administration doesn’t change the levels of cytokines,which indicates that it may not break the helper T cell (Th)1/Th2 balance.

Research on characters of mycobacteriophage D29 aerosol / 中华微生物学和免疫学杂志

Objective To investigate the aerosolized livability,aerosolized quantity and aerosol particle diameter,etc. of phage D29. Methods Phage D29 aerosol was produced in the aerosol test cabinet in negative pressure laboratory. TSI3321 aerodynamic particle sizer spectrometer was used for detecting the diameter of the aerosol particle. Bioaerosol particle median diameter was tested with Anderson six grade microorganism sampler. The aerosolized livability and quantity of phage D29 were determined by the variations of the concentrations and quantities of phage D29 before and after aerosolization.Results The aerodynamic diameter of phage D29 aerosol was 0.872 μm. Bioaerosol particle median diameter was 2.21 μm. The livability after aerosolization for 5,15,30,45,and 60 min were 89.78％,77.19％,48.86％,33.99％,30.12％,respectively. The aerosolized quantity of phage D29 was 232 μl/min. Conclusion The characters of the aerosolized livability,aerosolized quantity and aerosol particle diameter of phage D29 were thought to be suitable for further research into aerosol inhalation treatment of Mycobacterium tuberculosis infection in animals.

Abiological protective respirator with equal protection level of the half face mask / 医疗卫生装备

Medium filtering efficiency and loading capacity have been evaluated using staphylococcus aureus aerosol,0.75?m NaCl aerosol and Ecoli.F2 phage aerosol,and the face fit factor of actual wearing has been tested under eight predefined activities.The results have shown that the filtration efficiencies of respirator for the three kinds of tested aerosol were above 99 percent,the breathing resistance was less than 250 Pa,and while the load reached 150mg,the breathing resistance of the respirator was still below standards.The fit factors of most of the objects were over the detection capacity of the international standard test set.Our mask offers the best biological protection quality of all the protection equipments in international market.The new biological protective respirator comes to the equal protection result of the half face mask.It can be stored in a flat surface construction form,while be used in the cavity construction style.It is convenient for the troops to be equipped and applied for its smaller physical volume and lighter weight.