ABSTRACT
AIMS: To compare the inactivation rate of Venezuelan equine encephalomyelitis (VEE) virus in liquids to that of Sindbis virus (SV, another alphavirus) and to a bacteriophage (MS2) generally used as a viral simulant in the development of countermeasures in biodefense. METHODS AND RESULTS: Viruses were inoculated into liquids and viral titres were determined at various times postinoculation. The viruses were stable in distilled-deionized (dd) water at 4 degrees C during the 21 days of the study. The inactivation rates of VEE and SV in dd water at 21 and 30 degrees C were very similar (between 0.12 and 0.14 log(10) per day), while MS2 was three-fold slower. In tap water (chlorine content between 4 and 5 ppm) at 21 degrees C, VEE and SV were inactivated at twice the rate measured in dd water. CONCLUSIONS: The inactivation rates of VEE and SV were similar to each other and faster than MS2 in all liquids tested. SIGNIFICANCE AND IMPACT OF THE STUDY: VEE is likely to remain viable for many days after release into water, snow, or even chlorinated tap water. SV can be used to estimate the persistence of VEE in liquids, but using MS2 as a simulant would overestimate of the stability of VEE.
Subject(s)
Bacteriophages/isolation & purification , Encephalitis Virus, Venezuelan Equine/isolation & purification , Sindbis Virus/isolation & purification , Water Microbiology , Chlorine , Temperature , Time Factors , Water Supply/analysisABSTRACT
A simple procedure for the estimations of standard errors in hormone binding parameters derived from Scatchard analysis is proposed by assuming an univariate linear regression statistic model. The complete set of necessary formulae is presented and a practical way for calculation is solved using the binding of human growth hormone to rat adrenal membranes, as a practical example. The comparison between the results obtained by the method proposed and by using a well proved and accepted computer program, shows unequivocally that the differences are practically undistinguishable. The complete program to calculate the Scatchard parameters and their statistical analysis is available on request.
Subject(s)
Binding Sites , Computers , Receptors, Cell Surface/metabolism , Regression Analysis , Software , Iodine RadioisotopesABSTRACT
A simple procedure for the estimations of standard errors in hormone binding parameters derived from Scatchard analysis is proposed by assuming an univariate linear regression statistic model. The complete set of necessary formulae is presented and a practical way for calculation is solved using the binding of human growth hormone to rat adrenal membranes, as a practical example. The comparison between the results obtained by the method proposed and by using a well proved and accepted computer program, shows unequivocally that the differences are practically undistinguishable. The complete program to calculate the Scatchard parameters and their statistical analysis is available on request.