Radiation Inactivation of Coronavirus Infection Pathogen by the Example of Transmissible Gastroenteritis Virus.

In recent years, members of the Coronaviridae family have caused outbreaks of respiratory diseases (MERS, SARS, and COVID-19). At the same time, the potential of radiation-induced inactivation of this group of viruses have been little studied, although radiation technologies can be widely used both in the processing of personal protective equipment and in the sterilization of vaccines. In the present work, the effect of 10 MeV electron beams and 7.6 MeV bremsstrahlung on the coronavirus infection pathogen (transmissible gastroenteritis virus) has been studied in vitro. In the given experimental conditions, irradiation with photons turned out to be more effective. The virus-containing suspension frozen at -86°C was the most resistant to radiation: the dose required for complete inactivation of the virus in this case was from 15 kGy, while for the liquid suspension and lyophilized form the sterilizing dose was from 10 kGy. At lower radiation doses for all samples during passaging in cell culture, residual infectious activity of the virus was observed. These differences in the efficiency of inactivation of liquid and frozen virus-containing samples indicate a significant contribution of the direct effect of radiation.

Evaluation of Morphological and Histological Changes of Aggregated Lymph Nodes in the Small Intestine after Imofan Treatment in Immunosuppressed Rats.

Diffuse nodular lymphoid hyperplasia is a rare gastrointestinal disease that can be diagnosed by multiple nodules in the small intestine, large intestine, or both. Immunodeficiency and infections are the common situations that lead to the diffusion of nodular lymphoid hyperplasia. For instance, Giardia lamblia and Helicobacter pylori are the major pathogens leading to this disorder. Diffuse nodular lymphoid hyperplasia leads to allergic reactions, immunodeficiency, and autoimmune diseases. Imunofan-RDKVYR Peptide-is a potential agent in regenerative medicine. The present study aimed to investigate morphological features of the aggregated lymphoid nodules of the small intestine after the Imunofan (IM) administration following Cyclophosphamide-induced immunosuppression. In total, 72 Wistar male rats were randomly divided into two groups (n=36). Group I was considered the control group, and group II was subjected to intramuscular injections (needle 21 G) of0.2 ml of normal saline following the Cyclophosphamide-induced immunosuppression on the 2nd, 4th, 6th, 8th, and 10th days of the experiment. The animals in group II were injected with Cyclophosphamide at a dose of 200 mg/kg bodyweight to induce immunosuppression. The animals in the experimental group (n=36) were subjected to intramuscular injections (needle 21 G) of the 0.2 ml IM at a dose of 0.7µg/kg body weight on the 2nd, 4th, 6th, 8th, 10th days of the experiment. The results of the study indicated that on the 7th day in group II, the length and width of the aggregated lymphoid nodules increased, as well as the height and width of the lymphoid nodules and internodular zones as structural components of the lymphoid formations in the small intestine. In group I, by the 30th day of the experiment, the linear dimensions of the aggregated lymphoid nodules exceeded, but to a lesser extent than on the 7th day of the experiment which explains the ability of IM to neutralize the effects of Cyclophosphamide. It should also be noted that the IM was performed to regenerate damaged cells which helped maintain the population of lymphocytes in the limb and led to an increase in linear dimensions (length and width) not only between the joint but also in the lymph nodes.

Evaluation of Rat Brain Morphology Following the Induction of Acute Meningitis Treated with Ceftriaxone.

The soft and delicate tissue of the brain, which is the center of our coordination, is protected by its surrounding layers. The disruption of these layers results in complicated situations and serious health problems. The brain has three protective layers of bone or skull tissue, the blood tissue layer, and finally the meningeal layer. The layer of blood tissue contains the blood vessels that are located between the skull and the meningeal membranes. If germs or foreign matter enter the fluid through the blood vessels under any circumstances and cause infection, the bones that protect the meninges will break and cause tissue damage. The present study aimed to assess the histological and immunohistochemical characteristics of the brain of rats that underwent induced acute purulent pneumococcal meningitis after antibiotic therapy with Ceftriaxone. A number of 20 white adult male Wistar rats were assigned to three groups. The first group (n=5) regarded as the control were injected with a saline solution into the subarachnoid space in an equivalent amount. The second and third groups of rats (n=5 and 10, respectively) were infected with acute purulent meningitis by the injection of 10 µl of Streptococcus pneumoniae (S. pneumonia) suspension into the subarachnoid space of the brain using a 23-G needle. The various areas of the brains of rats after meningitis induced by S. pneumoniae were examined after the treatment with Ceftriaxone. The S. pneumoniae culture was injected into the subarachnoid space in the area of the rhomboid fossa. Treatment started 18 h after the injection. On day 10, a repeated puncture was performed with the analysis of cerebrospinal fluid in order to confirm the absence of meningitis; thereafter, the animals were taken out of the experiment. No signs of meningitis were found on histological examination. Mild perivascular and pericellular focal edema were revealed with signs of overload of the lymphatic system in the brain and focal ischemic changes in neurons. The investigation of expression with caspase-3 revealed a positive reaction of individual neurons. A positive reaction with antibodies to NeuN and Doublecortin was detected in most neurons; moreover, Glial fibrillary acidic protein (GFAP)-positive astrocytes and their processes were visualized in all layers of the brain substance. The reaction with neuron-specific enolase (NSE), microtubule-associated protein 2 (MAP-2), CD 31, and CD 34 was negative. Typical structure and pictures pointed to an intact brain and purulent meningitis in the first and second groups. The microscopic image and the changes revealed during immunohistochemistry by dual corticosteroid antibodies and neuronal nuclear protein were characterized by predominantly cytoplasmic and perinuclear reactions, respectively. Some neurons are positive for caspase-3 and are related to changes in the characteristic of premature aging.

A Unique Prototypic Device for Radiation Therapy: The p53-Independent Antiproliferative Effect of Neutron Radiation.

Radiation therapy with heavy particles including neutrons, an otherwise therapeutically perspective because of its high tissue penetration and efficient tumor damage, is currently limited by the lack of adequate equipment. An NG-24 generator (140 kg, 42 × 110 cm, ~1011 particles/s, > 14 MeV) has been designed and engineered to replace the huge and environmentally harmful neutron reactors, cyclotrons, and accelerators with a compact, portable, safe, and potent source of high-energy neutrons. We demonstrate that the neutron beam produced by NG-24 causes a significant antiproliferative effect on human tumor cell lines regardless of the status of the anti-apoptotic p53 protein. Phosphorylation of histone 2A and increased amounts of p21, cyclin D, and phospho-p53 were detectable in HCT116 colon carcinoma cells (wild-type p53) irradiated with 4 Gy several days post-treatment, accompanied by G2/M phase arrest. These treatments dramatically reduced the ability of single cells to form colonies. In the HCT116p53KO subline (p53 -/-), the G2/M arrest was independent of the aforementioned mechanisms. Hence, the NG-24 generator is a source of a powerful, therapeutically relevant neutron flux that triggers a p53-independent antiproliferative response in tumor cells.

Application of water-soluble nanofilters for collection of airborne Mycobacterium tuberculosis DNA in hospital wards.

A simple inexpensive technique for collection of airborne biomarkers of nosocomial infections is described. Biomarkers were collected on water-soluble electrospun nanofilters attached to a household vacuum cleaner from 6-10m(3) of air in 10-15min within several wards of a tuberculosis clinic. Filters were then dissolved in water and tested for the presence of the IS6110 and regX3 genes of Mycobacterium tuberculosis (MTB) using real-time polymerase chain reaction. It was demonstrated that trace amounts of airborne MTB DNA (>3gene copies/m(3)) were always present in the air and on the surfaces in the wards occupied with tuberculosis patients having positive smear tests.

Effect of different doses of transmitters on the mechanisms of adaptation.

We studied the responses of the organism to administration of autonomic transmitters in different doses: epinephrine (from 0.0000001 to 300 µg per 100 g body weight), serotonin (25, 50, 250, and 500 µg), and their combinations. The concentrations of biogenic amines in the blood and hypothalamus and parameters of oxidative and antioxidant systems, immune status, and blood coagulation and anticoagulation systems were analyzed. Cyclic dose-dependent variations in the levels of transmitters were revealed that dynamically changed their properties of syntoxins and catatoxins.

[Analysis of occupational morbidity causes among workers of Lipetsk region]. / Analiz prichin professional'noi zabolevaemosti trudiashchikhsia Lipetskoi oblasti.

Higher occupational morbidity is not invariably a negative factor, sometimes being an indicator of good diagnostics and registration of occupational diseases, aimed to realize constitutional right for compensation of health damage caused by hazardous work conditions.

Immobilization of proteins in immunochemical microarrays fabricated by electrospray deposition.

Electrospray (ES) deposition has been applied to fabricate protein microarrays for immunochemical assay. Protein antigens were deposited as arrays of dry spots on a surface of aluminized plastic. Deposition was performed from water solutions containing a 10-fold (w/w of dry protein) excess of sucrose. Upon contact with humid air, the spots turn into microdroplets of sucrose/protein solution from which proteins were either adsorbed or covalently linked to clean or modified aluminum surfaces. It was found that covalent binding of antigens via aldehyde groups of oxidized branched dextran followed by reduction of the Schiff bonds gives the highest sensitivity and the lowest background in microarray-based ELISA, as compared to other tested methods of antigen immobilization. The minimum concentration of a primary mouse antibody detected in indirect ELISA with such antigen microarrays was approximately 0.3-1.0 ng/mL for ELF-97 or BCIP/NBT substrates of alkaline phosphatase.

Electrospray deposition as a method for mass fabrication of mono- and multicomponent microarrays of biological and biologically active substances.

Electrospray of protein and DNA solutions is currently used to generate ions for mass spectrometric analysis of these molecules. Deposition of charged electrospray products on certain areas of a substrate under control of electrostatic forces is suggested here as a method for fabrication of multiple deposits of any size and form. For example, multiple dots of protein, DNA, or other organic substances can be deposited simultaneously through an array of holes in a dielectric mask covering any slightly conductive substrate (membrane, wet glass, semiconductor, etc.). If every new substance is deposited after a shift of the mask with respect to the substrate, a multicomponent matrix is created under each hole. It is demonstrated that dots as small as 2-6 microns can be fabricated by such an electrospray deposition (ESD). It is also demonstrated that the ES-deposited proteins and DNA retain their ability to specifically bind antibodies and matching DNA probes, respectively, enabling use of the ESD fabricated matrixes in Dot Immuno-Binding (DIB) and in DNA hybridization assays.

Electrospray deposition as a method to fabricate functionally active protein films.

Electrospray ionization is a routine method in MS analysis of proteins and other biopolymers. Deposition of the electrospray products onto a conductive electrode is suggested here as a means to manufacture functionally active protein films. Recovery of the specific hydrolytic activity of the electrosprayed alkaline phosphatase (AP) was used as a probe for preservation of protein intactness in the electrospray deposition (ESD). It was shown that protein inactivation upon ESD is highly dependent on voltage and current used. Humidity and the presence of protective substances in solution also affect the process. Complete preservation of the enzyme activity was observed when the ESD was performed at low current and humidity in the presence of disaccharides.

Effect of nuclear protein HMG1 on in vitro slippage synthesis of the tandem repeat dTG x dCA.

Tandem repeats of simple doublet and triplet sequences occur with high frequency in the DNA of eucaryotes. Among the most frequent is the repeat of dTG, which has unusual structural properties. We show here that HMG1 (modeled by the second HMG box motif from HMG1 of the rat, HMGb) binds to complexes formed from annealing unequal lengths of dTG x dCA and inhibits the in vitro elongation of these complexes by the Klenow fragment of DNA polymerase I at 37 degrees C. At 46 degrees C, HMGb enhances the elongation. Polylysine inhibits elongation at both temperatures. These results show that the stability of this repeat in vivo can be influenced by the presence of basic proteins in general, and more selectively by the abundant nuclear protein HMG1.

[State of cardiovascular and blood coagulation systems during prolonged exposure to extreme stimuli]. / Sostoianie serdechno-sosudistoi i koaguliatsionnoi sistem organizma pri dlitel'nom deistvii ékstremal'nykh razdrazhitelei.

The studies covered complex effects of local shock vibration at extreme levels and ambient heat load with intensive impulse noise and general vibration in association with heavy physical work. The experiments on animals assessed influence of low temperatures on cardiovascular and hemocoagulation systems. Analysis of those clinical and experimental data proved that extreme and subextreme levels of long-acting factors induce disorders of hemostasis-depression of anticoagulation, that is similar to 1 phase of DIC syndrome. These results are important for diagnosis of premorbid and pathologic conditions.

A magnetic micromethod to measure Young's modulus of protein crystals and other polymer materials.

A new micromethod has been developed to measure the elastic modulus of polymer materials. It is based on measurements of bending of a polymer sample in a periodic uneven magnetic field acting on a small permanent magnet attached to the sample free end. As compared to the other methods known, it combines simplicity of resonant methods with a possibility to perform measurements at different frequencies in liquids under normal and high pressures. The method is specifically designed to measure the temperature dependence of cross-linked protein crystals under different conditions.

Stabilization of helical peptides by mixed spaced salt bridges.

Whether or not surface salt bridges have a strong stabilizing effect on the native structure in proteins remains uncertain. Previous studies of model peptides have shown that salt bridges spaced at i,i +4 along the chain are more stabilizing than those spaced at i,i +3, with a preference for the order acid-base rather than base-acid from N to C terminus. An analysis of the effect of spacing the ion pairs in short helical peptides is presented, in which acidic and basic side chains spaced two or three residues apart alternate along the chain. The mixed spacing proves to be stabilizing relative to pure spacings. A control peptide in which salt bridges were spaced uniformly three residues apart proved to form a beta-sheet structure rather than alpha-helix. This is due to formation of a silk-like apolar face consisting of alanine side chains; the mesoscopic structure formed by these sheets can be imaged by scanning microscopy.

New polyacrylamide gel-based methods of sample preparation for optical microscopy: immobilization of DNA molecules for optical mapping.

New methods have been developed for rapid immobilization of biological macromolecules and other microscopic objects from aqueous solution at gel/gel, gel/solid and gel/solution interfaces using thin polyacrylamide gels covalently bound to glass surfaces. When quickly spread over a dry gel, an aqueous sample loses most of its water and low-molecular-weight solutes due to migration of these components into the gel. All optically observable objects thus become concentrated at the gel surface and may be easily located by light microscopy. Based on this, a procedure for binding DNA at a positively charged gel/solution interface was developed. A mild immobilization of the DNA molecules was obtained, allowing 'all in focus' observations of DNA digestion by restriction endonucleases with an apparent rate close to that in solution.

Ionic conductivity, transference numbers, composition and mobility of ions in cross-linked lysozyme crystals.

Micromethods for measurements of electric conductivity, transference numbers and concentrations of inorganic ions within immobilized protein crystals have been developed and applied to study tetragonal lysozyme crystals cross-linked with glutaraldehyde. Donnan equilibria and mobilities of ions in this crystal were calculated using the data of these methods and the data of crystal pH titration. Taken together these results characterize the lysozyme crystal as an ion exchanger whose electrical properties and ion composition differ greatly from those of the external solution. Although anions transfer most of the current in the crystals, anion mobility is considerably lower than that of cations. Mobility of all ions in the crystal is considerably lower than in solution (3.5-50 times for cations and 120-330 times for anions) and depends on steric restrictions and charges of both ions and lysozyme molecules. Similar features in behavior of crystalline and biological channels are discussed.

[The blood coagulating activity in burns]. / Sostoianie gemokoaguliruiushchei aktivnosti krovi pri ozhogakh.

Data obtained in experiments in 80 rats and in clinical observations of 24 patients with burns of the II and IIIA degrees showed the activation of vasculo-thrombocytic and procoagulant links of the hemostasis system with a simultaneous depression of the anticoagulative blood system. The thermal trauma is followed by a dramatic decrease of the concentration of heparin, fibrinogen, decreased activity of antithrombin-III, fibrinolysis and plasminogen activators. There was a simultaneous growth of concentration of antiplasmins (alpha 2-macroglobulin and alpha 1-antitrypsin).

[X-ray fluorescent study of the ionic composition of lysozyme crystals]. / Rentgenofluorestsentnoe issledovanie ionnogo sostava kristallov lizotsima.

The method of the studying of the ionic content in the protein crystals by X-ray fluorescence spectroscopy is proposed. The ionic content of the tetragonal glutaraldehyde--cross-linked lysozyme crystals in the 2- 11 pH range and upon the low and high ionic strengths is studied. The acid-base titration of the lysozyme crystals is carried out for determination of the pH-dependence of the net charge of the lysozyme molecule within protein crystal. It has been shown that ionic content in the protein crystal channels is determined mainly by the Donnan potential. The specific binding of the bromide-ions with lysozyme molecules is revealed and possible binding sites are discussed.