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Extreme Medicine

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The level and duration of protective immunity are often analyzed qualitatively or semi-quantitatively. The same strategy is applied to the analysis of antibody dynamics. At some point in time t after exposure or immunization, the presence of immunity against the infection is inferred from the level of specific antibodies by comparing it to a reference value. This approach does not account for the stochastic nature of human disease after exposure to a pathogen. At the same time, it is not fully clear what antibody level should be considered protective. The aim of this study was to develop a mathematical model for quantitative determination of protective immunity against SARS-CoV-2 and its duration. We demonstrate that the problem of describing protective immunity in quantitative terms can be broken down into 2 interrelated problems: describing the quantitative characteristics of a pathogen’s virulence (in our case, the pathogen is SARS-CoV-2) and describing the dynamics of antibody titers in a biological organism. Below, we provide solutions for these problems and identify parameters of the model which describes such dynamics. Using the proposed model, we offer a theoretical solution to the problem of protective immunity and its duration. We also note that in order to quantitatively determine the studied parameters in a homogenous population group, it is necessary to know 5 parameters of the bivariate probability density function for correlated continuous random variables: the infective dose of the pathogen and the antibody titer at which the disease develops and which are still unknown.
Wipe sampling is widely used for microbiological control purposes. Sanitary and chemical studies also include analysis of samples wiped from the work surfaces during routine and periodic working conditions safety inspections at chemical facilities. The analysis also allows assessing the toxicity and hazard of items/structures that could be in contact with highly toxic substances. This study aimed to investigate the capabilities and limitations of the surface wipe sample analysis method in control of residual contamination of equipment and building structures of a former chemical weapons destruction facilities (CWDF) with sulfur mustard and O-isobutyl-S(2-diethylaminoethyl) methylphosphonothioate (VR), as well as their degradation products. Gas chromatography with tandem mass spectrometry (GC-MS/MS) enabled identification of the sulfur mustard markers, high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) allowed identifying VR markers. An assessment of the matrix influence on the results of GC-MS/MS and HPLC-MS/MS analysis was carried out. The matrix effect was established to affect the results the most in case of HPLC-MS/MS analysis: for GC-MS/MS analysis of target substances, the matrix factor averaged at 60–80%, for HPLC-MS/ MS it was less than 40%. The average percent sulfur mustard recoveries from three types of surfaces (PVC tiles, laminate and metal plates) was 9 ± 2%, 0.13 ± 0.02% and 0.10 ± 0.03%; in case of VR, the recoveries was 2.7 ± 0.5%, 11.8 ± 0.3% and 0.8 ± 0.1%, respectively. The limits of detection for sulfur mustard by GC-MS/MS and VR by HPLC-MS/MS were established at 0.001 MPL and 0.02 MPL, respectively. The developed approaches were applied to the analysis of wipe samples from the surfaces of the equipment and engineering structures of the former CWDF.
After elimination of the chemical weapons, it is necessary to relieve the consequences of operation of the chemical weapons destruction facilities (CWDF). This study aimed to assess the results of such relieve activities from the hygienic point of view. The assessment allows considering partial conversion of the CWDFs' infrastructure for civil purposes. At four CWDFs, the sites of contamination of equipment and infrastructural components with degradition products of organophosphorous agents (OPA) and blister agents (BA) were identified. The technologies that enabled analysis of the samples taken were high performance liquid chromatography with tandem mass spectrometry, gas chromatography–mass spectrometry, gas chromatography–tandem mass spectrometry, and atomic absorption spectroscopy with electrothermal atomization. The analysis revealed contamination of building structures, equipment, utility lines, waterproofing, heatinsulating, and other materials inside the CWDF process buildings, regardless of their purpose, with OPA and BA degradation products. In the absence of hygienic standards and information on their toxicity, it was impossible to assess the hazard thereof. In all the samples taken, the residual content of toxic substances was below the limit of detection of the measurement methods applied, i.e., none was found. The article presents a methodology for a stepwise hygienic assessment of the CWDF infrastructure to be converted and develops recommendations for its subsequent safe use. The conclusions state expediency of development of hygienic standards for the OPA and BA degradation products and development and certification of the relevant measurement procedures.

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COVID-19 belongs to the group of acute respiratory infections and it is often complicated with pneumonia. This study aimed to investigate manifestations of community-acquired pneumonia (CAP) epidemic process during the COVID-19 epidemic in the Russian Federation. We analyzed the official statistical data reporting the incidence of CAP in the Russian Federation in 2013–2020 and incidence of COVID-19 as registered in March–July 2020. The mean average annual CAP incidence rate that we calculated and the 2020 CAP incidence prediction allowed assessing the relationship between CAP and COVID-19. It is shown that the long-term dynamics of the incidence of CAP in the Russian Federation is characterized by a pronounced upward trend with an average annual growth rate of 6.4%. The share of adult population among the CAP cases is the largest; on average, it is 64.7% (95% CI [63.1; 66.3]). In 2020, against the background of SARS-CoV-2 circulation, the discrepancy between the actual incidence of CAP and the predicted figures reached and exceeded 558% (in July 2020). As the COVID-19 epidemic developed, the incidence of CAP was registered to increase. There was established a direct and significant correlation between the incidence of CAP and COVID-19 (rxy = 0.932; p <0.01).
The 67-th Session of the United Nations Scientific Committee on the Effects of the Atomic Radiation (UNSCEAR) took place in the form of videoconferences during 2-6 November 2020. Within the framework of the meetings of the Working group and subgroups the documents of the following projects were discussed: R.741 «Evaluation of medical exposure to ionizing radiation»; R.742 «Levels and effects of radiation exposure due to the accident at the Fukushima Daiichi nuclear power station: implications of information published since the UNSCEAR 2013 report»; R.743 «Biological mechanisms relevant for the inference of cancer risks from lowdose and low dose rate radiation»; R.744 «Evaluation of occupational exposure to ionizing radiation»; R.745 «Second primary cancer after radiotherapy»; R.746 «Epidemiological studies of radiation and cancer»; R.747 «Evaluation of public exposures to ionizing radiation from natural and man-made sources»; Project 67/7 «Implementation of the Committee's strategy to improve collection, analysis and dissemination of data on radiation exposure». The Committee also discussed the future research program (2020–2024); report to the UN General Assembly; public outreach activity including the strategy for the period 2020–2024.