A mathematical model for developing hepatitis E virus infection in human population

Hepatitis E is an acute viral infectious disease transmitted by fecal-oral route mainly through fecally contaminated drinking water, with cyclic outbreaks and frequent development of acute hepatic encephalopathy in pregnant women. Hepatitis E epidemic outbreaks occur in Central Asia, Africa and Latin America, whereasChina,India,Turkmenistan,Kazakhstan,Tajikistan,Uzbekistan,Kyrgyzstan,Bolivia,Mexico, andTaiwanrepresent endemic geographic regions. Hepatitis E in the structure of acute viral hepatitis morbidity during outbreaks ranges from 64.7% to 80%, whereas sporadic morbidity may be up to 10 to 18.8%. In contrast, percentage of hepatitis E in acute viral hepatitis varies from 0.5% to 12.6% in European countries and some territories of theRussian Federation. The latent active virus circulation was confirmed in various regions of theRussian Federation. All introduced cases were related to recent traveling to the regions with high incidence of hepatitis E, which course clinically did not differ from standard hepatitis E infection, but no cases of infection were recorded after exposure. Lack of contact transmission in this case was associated with low virus survival in environment. Patients with any clinical form including anicteric serve as a source of infection. An increased risk of hepatitis E infection is typical for livestock workers dealing with pigs, employe es of meat processing plants engaged in primary meat carcass processing and working at slaughterhouse. According to the World Health Organization, 20 million cases of hepatitis E virus infection are recorded annually, among which 3 million cases account for acute hepatitis E and related 70 000 lethal outcomes. Chronic liver disorders comprising up to 70% followed by death of pregnant women (40%) as well as acute liver and kidney failure reaching as low as 4% result in lethal outcome in hepatitis E patients. Creating a mathematical model for development of hepatitis E infection could allow to predict changes in its morbidity rate at controlled area. Here, for the first time we propose a mathematical model for developing hepatitis E in human population based on disease course, which may potentially predict an incidence rate for the most dangerous icteric hepatitis E as well as assess amount of individuals susceptible to it at morbidity rise in the geographic region

Percutaneous interventions in obstructive jaundice of cancerous genesis

The article presents a statistical assessment of the complications arising after performing percutaneous interventions in patients with obstructive jaundice of a tumor genesis.В работе представлена статистическая оценка осложнений возникающих после выполнения чрескожных вмешательств пациентам с механической желтухой опухолевого генеза

Study of the effect of polyelectrolytes with antiviral effect on the activity of influenza virus neuraminidase and the process of oxidative phosphorylation in mitochondrias of cells host organism

Aim. Study of the inhibitory effect of polyelectrolytes with antiviral effect against influenza neuraminidase. Determination of the type and inhibition constant. The study of the effect of polyelectrolytes (PE) on the process of oxidative phosphorylation in the mitochondria of cells host organism. Materials and methods. Purified influenza virus strains were used: A/VPCH/Weybridge (H7N7), A/Mallard Pennsylvania/10218/84 (H5N2), A/NIBRG-14 (H5N1) with an initial infectious titer of 4,5 lgTCD50/ml. PE solutions of polystyrenesulfonate with a degree of polymerization of 8 (PSS-8) in concentrations of 0,5—4,0 mM and polyallylamine (6 kDa) PAA (6 kDa) in concentrations of 0,5—4,0 μM. To determine the activity of influenza neuraminidase, influenza virus strains were used after the removal of low molecular weight inhibitors of neuraminidase by dialysis against water. The neuraminidase substrate was fetuin at final concentrations of 0,052 to 1,2 μM for PAA (6 kDa) and from 0,052 to 1,2 mM for PSS-8. As quantitative characteristics of respiration and phosphorylation of mitochondria, respiratory coefficients according to Lardi-Velman and Chans-Williams, as well as the ratio of ADP/O were used. Mitochondria were isolated from skeletal muscle. The determination of respiratory coefficients and the ratio of ADP/O) was determined by the polarographic method. Results. A noncompetitive type of inhibition of these PEs was detected in relation to the neuraminidase activity of influenza viruses with inhibition constants KI = 1,6 ± 0.08 μM for PAA (6 kDa) and KI = 1,7 ± 0.085 mM for PSS-8. Respiratory coefficients and the ratio of ADP / 0 were determined in the absence and after addition of PSS-8 and PAA (6 kDa) to mitochondria at concentrations of 20 mM and 10 μM, respectively. A decrease in respiratory coefficients and an ADP/O ratio was observed, indicating an inhibition of the enzymes of the electron-transport chain of mitochondria. At concentrations of less than 20 mM and 10 μM for PSS-8 and PAA (6 kDa), all indicators did not significantly change. Conclusion. The non-competitive mechanism of inhibition of the neuraminidase activity of the influenza PE viruses is explained by the conformational changes in the molecules of the enzyme and/or enzyme-substrate complex and, accordingly, the structural and functional changes in its secondary structure. When going beyond the range of non-toxic concentrations of20 mM for PSS-8 and 10 μM for PAA (6 kDa), inhibition of the mitochondrial respiratory chain enzymes was observed while maintaining the antiviral effect

THE STUDY OF VIRUSES REPRODUCTION IN CELL CULTURES BY THE METHOD OF MATHEMATICAL MODELING

Abstract. In the study the mathematical analysis of viruses reproduction in cell culture using the Marchuk’ mathematical model to predict  reproduction of virus in one or another cell cultures has been conducted. The obtained theoretical results are corresponded to the experimental data on reproduction of rubella virus in cell cultures RK-13 and BHK-21. The sum of theoretical and experimental results can be used to select the optimal cell cultures for virus cumulation

Statistical Analysis of the Model Parameters of the Epidemic Situation

A calculation method and a variation method of parameters of the epidemic situation model taking into account external risks is proposed. The detailed step-by-step algorithm available in the application Exel for the calculation and analysis of the model parameters based on the results of observations is given. The prognosis of the epidemic situation with the estimation of the disease outbreak duration and the total number of population members involved in the outbreak is constructed. We investigated the epidemic situation by an example of reports of a diseases group acute viral respiratory infections-flu in one of the districts of the Moscow region

THE STUDY OF INFLUENZA VIRUS NEURAMINIDASE HYDRATION DEGREE

It is known that the functioning of many proteins and enzymes depends on the degree of hydration of their surfaces. In our studies, neuraminidase (NA) of influenza virus was selected as a model for surface antigenic viral protein. The Brunauer–Emmett–Teller (BET) model of adsorption was used to calculate the values of water monolayer (am) at different values of water vapor pressure. The obtained BET isotherms allow for concluding that hysteresis takes place manifested by the difference between the monolayer am values for sorption and desorption of water from the surface of the enzyme, which is probably associated with a high degree of cooperation of the hydration shell formed. The maximum binding of water molecules was observed for the vapor pressure p/ps value of 0.65 and was am = 224 water molecules per a molecule of the enzyme. Basing on the calculated surface area of a NA tetramer (S = 256 nm2 ) and the maximum projection area of water molecule, it may be concluded that the entire surface of the enzyme is completely covered with a water monolayer. For said am value the maximum activity of NA was observed, whereas the minimum enzyme activity corresponded to the am value of 98 water molecules per a molecule of the enzyme, which corresponded to the water vapor pressure p/pS value of 0.38. Thus, for the influenza virus NA protein a dependency of the enzymatic activity on the degree of hydration of the surface of the enzyme is demonstrated. The dependence of immunogenicity of influenza virus from the extent of hydration of NA

Epidemic Mumps in Russia: Epidemic Situation, Key Challenges and Solutions

Relevance.In the second decade of the 21st century, mumps still attracted the attention of scientists and practitioners around the world for their epidemiological, social and economic importance. A ubiquitous but uneven spread of mumps infection has been established in various regions of the world: in Europe, the Eastern Mediterranean, Southeast Asia, Africa, America, and the Western Pacific.Aim. Present the current state of the incidence of mumps in the Russian Federation.Conclusions. The current epidemic situation of mumps in the Russian Federation is characterized by a predominance in the age structure of the incidence of adolescents and young working age people and determines the need to develop and introduce in medical activity a standard definition of the clinical case of mumps for correct verification of the diagnosis with subsequent laboratory confirmation. The emergence of the phenomenon of «growing up» of mumps and the registration of periodic outbreaks in the long-term practice of vaccination dictates the need to improve further vaccination prevention tactics with an emphasis on the adult population as part of the implementation of the National preventive vaccination calendar