[Clinical anatomy of the Bernasconi-Cassinari artery]

The article provides a comprehensive overview of the Bernasconi-Cassinari's artery (marginal tentorial branch of internal carotid artery, r. marginalis tentorii a. carotis internae). It includes information on the history of its discovery, anatomical features, and topography. The interrelation between the anatomical features of this artery and the presence of neurological pathology in patients is discussed, along with neurosurgical treatment methodologies.

Urticaria exacerbations and adverse reactions in patients with chronic urticaria receiving COVID-19 vaccination: Results of the UCARE COVAC-CU study

BACKGROUND

Concern about disease exacerbations and fear of reactions after coronavirus disease 2019 (COVID-19) vaccinations are common in chronic urticaria (CU) patients and may lead to vaccine hesitancy.

OBJECTIVE

We assessed the frequency and risk factors of CU exacerbation and adverse reactions in CU patients after COVID-19 vaccination.

METHODS

COVAC-CU is an international multicenter study of Urticaria Centers of Reference and Excellence (UCAREs) that retrospectively evaluated the effects of COVID-19 vaccination in CU patients aged ≥18 years and vaccinated with ≥1 dose of any COVID-19 vaccine. We evaluated CU exacerbations and severe allergic reactions as well as other adverse events associated with COVID-19 vaccinations and their association with various CU parameters.

RESULTS

Across 2769 COVID-19-vaccinated CU patients, most (90%) received at least 2 COVID-19 vaccine doses, and most patients received CU treatment and had well-controlled disease. The rate of COVID-19 vaccination-induced CU exacerbation was 9%. Of 223 patients with CU exacerbation after the first dose, 53.4% experienced recurrence of CU exacerbation after the second dose. CU exacerbation most often started <48 hours after vaccination (59.2%), lasted for a few weeks or less (70%), and was treated mainly with antihistamines (70.3%). Factors that increased the risk for COVID-19 vaccination-induced CU exacerbation included female sex, disease duration shorter than 24 months, having chronic spontaneous versus inducible urticaria, receipt of adenovirus viral vector vaccine, having nonsteroidal anti-inflammatory drug/aspirin intolerance, and having concerns about getting vaccinated; receiving omalizumab treatment and Latino/Hispanic ethnicity lowered the risk. First-dose vaccine-related adverse effects, most commonly local reactions, fever, fatigue, and muscle pain, were reported by 43.5% of CU patients. Seven patients reported severe allergic reactions.

CONCLUSIONS

COVID-19 vaccination leads to disease exacerbation in only a small number of CU patients and is generally well tolerated.

[Study of the effect of Unifuzol on cognitive impairment and damage to the hippocampus and cerebral cortex during course administration to rats with bilateral stenosis of the common carotid arteries, causing chronic circulatory failure]

OBJECTIVE

To study the effect of Unifuzol (L-arginine sodium succinate) on cognitive impairment, cerebral blood flow, and damage to the tissues of the hippocampus and cerebral cortex during a 10-day course of administration to rats with chronic cerebral ischemia (CCI) caused by bilateral stenosis of the common carotid arteries (CCA).

MATERIAL AND METHODS

The study was conducted on male rats with CCI caused by bilateral stenosis of the CCA by 60%. 40 days after surgery, rats received Unifusol (21, 42 and 84 ml/kg), nicergoline (10 mg/kg), citicoline (500 mg/kg) or placebo (0.9% NaCl) for 10 days. Next, cognitive impairments were assessed in the Morris Water Maze and the New Object Recognition (NOR) test, as well as the level of motor and exploratory activity in the Open Field test. The level of cerebral blood flow was determined immediately after the CCA stenosis and at the end of the experiment. Animals were euthanized in a CO₂ incubator, after which the brain was removed and subjected to morphometric analysis.

RESULTS

In animals that were modeled with CCA stenosis, pronounced behavioral and cognitive impairments occurred as a result of a decrease in blood flow in the vessels of the brain and subsequent changes in the tissues of the hippocampus and the cerebral cortex. Intravenous course administration of Unifuzol at doses of 42 and 84 ml/kg to animals with CCI was comparable in efficiency to nicergoline and citicoline, which was expressed in greater preservation of the cognitive abilities of animals in the Morris Water Maze and NOR tests. In the Open Field test, animals injected with Unifusol at doses of 42 and 84 ml/kg performed more acts of motor and exploratory activity than animals from the placebo group, and had a higher level of cerebral blood flow (compared to animals that were injected with citicoline). Based on the results of a morphological study, it was found that the most significant neuroprotective effect was provided by nicergoline and Unifuzol (at doses of 42 and 84 ml/kg).

CONCLUSION

Unifuzol at a course of administration at doses of 42 and 84 ml/kg, comparable to the reference drugs nicergoline and citicoline, reduces the severity of psychoneurological deficit in animals with CCI, comparable to them improves the microcirculation of brain tissues, preventing damage to brain tissues.

[Oxidative stress in the pathogenesis of stroke and its correction]

We reviewed the role of oxidative stress (OS) in the pathogenesis of ischemic (IS) and hemorrhagic stroke (HS). OS plays a major role in programmed cell death, increased permeability of the blood-brain barrier, astroglial and microglial activation, and local inflammatory response. We also reviewed the current state of neuro- and cytoprotection studies and their translation in clinical practice. With respect to experimental and clinical data the efficacy of long term administration of multimodal cytoprotective drug with antioxidant effect - ethylmethylhydroxypyridine succinate (Mexidol) is discussed during the acute and early recovery period after stroke.

[FEATURES OF THE USE OF ANTIBACTERIAL DRUGS IN PATIENTS WITH COVID-19]

The review traces the evolution of the section on the use of antibacterial drugs in the temporary guidelines of the Ministry of Health for the treatment of a new coronavirus infection. Diagnostic approaches that play an important role in deciding on the need and duration of antibacterial therapy are presented. Routine use of fluoroquinolones should be restricted due to the adverse safety spectrum. According to existing data, the tactic of short courses of antibacterial therapy for community-acquired pneumonia are not inferior in effectiveness to longer courses. Unjustified prescribing of antibiotics increases the cost of medical care, promotes the selection of resistant pathogens and leads to adverse side effects. Timely updating of clinical recommendations, implementation of programs to control the appointment of antibacterial agents in medical organizations and strengthening the role of the clinical pharmacology service can reduce these adverse events.

Ab ovo: Factors Affecting the Radial Stiffness of Thoracic Aorta Stent-Grafts

The aim of the investigation was to study the factors influencing the radial stiffness of the thoracic aorta stent-grafts with the stent elements made of nitinol tubes by laser cutting and thermal shape setting.

Infradian and Ultradian Rhythms of Body Temperature Resumption during Hibernation

The rhythms of short-term arousal episodes, associated with normalization of low body temperature, were studied in hibernating Erinaceus roumanicus. The episodes of body temperature recovery during hibernation were 1.7 times more incident during the acrophase of 4.058-day rhythm of glucocorticoid hormones, detected previously, than during the batiphase of this rhythm. Ultradian rhythm of arousal episodes conformed to a 4-h biorhythm: the maximum number of body temperature resumption episodes was recorded at 00.00-01.00, 04.00-05.00, 08.00-09.00, 12.00-13.00, 16.00-17.00, and 20.00-21.00. These data indicated that in mammals the mechanisms of infradian and ultradian rhythm maintenance were stable and did not depend on body temperature or were determined by external factors with periods of 4.058 days and 4 h.

[Chronic anal fissure: etiopathogenesis, diagnosis, treatment]

Etiology, epidemiology and pathophysiology of anal fissure are examined in the article in order to determine the most optimal treatment strategy. The authors concluded that the most effective treatment is combined approach using both minimally invasive surgery and various medicines for anal spasm reduction.

[Immunohistochemical study of the specific features of expression of matrix metalloproteinases 1, 9 in the photoaged skin, the foci of actinic keratosis and basal cell carcinoma]

Matrix metalloproteinases (MMPs) mediate the degradation of all types of collagens and other extracellular matrix components (elastin, proteoglycans, and laminin), their synthesis and accumulation play a key role in the hydrolysis of basement membrane. MMPs are involved in a wide range of proteolytic processes in the presence of different physiological and pathological changes, including inflammation, wound healing, angiogenesis, and carcinogenesis.

AIM

to study the specific features of MMP-1 and MMP-9 expression in different stages of skin photoaging, in the foci of actinic keratosis and basal cell carcinoma by immunohistochemical examination.

MATERIAL AND METHODS

12 samples of the healthy skin (6 samples of the eyelid skin with Glogau grade II photoaging; 6 ones of eyelid skin with Glogau grades III-IV photoaging) and biopsies from 8 foci of actinic keratosis and from 8 ones of basal cell carcinoma were examined. A positive reaction to MMPs was shown as different brown staining intensity in the cytoplasm of keratinocytes/tumor cells.

RESULTS

MMP-1 and MMP-9 expression was recorded in 67% of the histological specimens of the Glogau grade III photoaged skin and in 100% of those of Glogau grade IV. In the foci of actinic keratosis, the expression of MMP-1 was observed in 62.5% of cases and that of MMP-9 was seen in 87.5%. In basal cell carcinoma, the expression of MMP-1 and MMP-9 was detected in all investigated samples.

CONCLUSION

The immunomorphological findings are indicative of the important role of the level of MMP-1 and MMP-9 expression that is associated with the degree of progression of skin photoaging processes. Minimal MMP-1 and MMP-9 expression was recorded even in grades III-IV photoaging and in the foci of actinic keratosis. Intense MMP-1 and MMP-9 expression was detected in malignant skin epithelial neoplasms as different clinicomorphological types of basal cell carcinoma.

Seasonal Changes in Blood Cells and Biochemical Parameters in the Mongolian Hamster (Allocricetulus curtatus)

It was shown previously that the Mongolian hamster (Allocricetulus curtatus) is a mammalian species with irregular short hibernation. The purpose of the present study was to determine how this status affects seasonal changes in the biochemical and hematological parameters in A. curtatus males under a natural temperature and light regime. It was found that a reduction in circulating white blood cells, specifically lymphocytes, neutrophils, eosinophils, basophils, and monocytes, occurred in-winter. and bilirubin levels increased in spring. These characteristics make Mongolian hamsters closer to the true hibernating species. At the same time, the character of seasonal changes in the number of red blood cells, glucose, total protein, creatinine, and albumin is closer to species with torpor.

[Assessment of skin photoaging in middle-aged and elder patients with non-melanoma skin cancers]

The development of methods of early detection of non-melanoma skin cancers, assessment of risk factors, including photoaging, by means of non-invasive techniques are the main research interests of modern dermato-oncology and gerontology. In our study we aim to investigate the range of clinical features of photoaging in 92 patients older than 50 years (50 patients had malignant epithelial skin tumors (actinic keratosis, basal cell carcinoma), to reveal risk factors for basal-cell carcinoma using adapted SCINEXA scale and to assess of the pathomorphological features of dermathoheliosis using reflectance confocal microscopy. The assessment of photoaging by means of SCINEXA with subsequent non-invasive evaluation using reflectance confocal microscopy allows to evaluate the cumulative effect of the ultraviolet irradiation on the skin with objective criteria. That algorithm is perspective in terms of early detection of the risk factors of non-melanoma skin cancers.

[Relationship between warfarin dosing and activity of CYP2C9 assessed by the content of losartan and its metabolite E-3174 in the urine of patients with mechanical prosthetic heart valves]

We evaluated effect of activity of cytochrome P450 CYP2C9 on maintenance doses of warfarin in 33 patients with implanted artificial heart valves. Losartan test was used for measurement of concentration of active metabolite E-3174 in urine. Concentration of E-3174 below 2500 ng/ml in patients with genotype CYP2C981/*1 with sensitivity 87% and specificity 66% predicted requirement of low doses (< 5 mg/day) of warfarin in the late postoperative period (odds ratio 14, 95% confidence interval 1.135 to 172.75).

[The application of radial hemolysis technique in detection of antibodies to avian influenza virus A (H5N1) and pandemic virus A (H1N1) pdm09]

The article discusses the results of study that demonstrated the possibility of successful application of radial hemolysis reaction in analyzing the human inoculation immunity to new strains of influenza virus serotype A - A (H5N1) and A (H5N2). The radial hemolysis reaction provides accurate results on introduction of erythrocytes of horse or sheep into hemolytic system instead of erythrocytes of hens applied previously. The technique combines high sensitivity (in comparison with reactions of hemagglutination-inhibition and micro-neutralization, correlation coefficient 0.84-0.85) and total absence of inhibitors impact on the reaction results. During the investigation of immune response of patients who had pandemic virus A (H1N1) pdm09, radial hemolysis reaction demonstrated not only primary detection of antibodies to virus-agent (67%) during pandemic, but also elective heightened sensibility in the zone of low titer serums (1:20) in hemagglutination-inhibition reaction. These characteristics are very important in analysis of antibodies levels at early stages of disease. The radial hemolysis reaction continues to be a reliable instrument in evaluating qualitative and quantitative indicators of humoral immunity in ill patients and persons inoculated with new strains of human influenza virus.

[Development of competitive enzyme immunoassay for the detection of influenza A(H5) virus antibodies]

An indirect enzyme immunoassay (EIA) using the purified fraction of surface viral glycoproteins (GP) as an antigen for solid phase sensitization was not shown to be a specific method for the differential detection of influenza A(HS) (HS-Ab) virus antibodies (Abs) due to total conservative epitopes in the structure of GPs of influenza A(H5) and A(H1NI) viruses. The cross activity of some monoclonal Abs (MAbs) to influenza A(H5) and A(HIN1) viruses, which had been obtained at the Research Institute of Influenza, was proof of the presence of total immunodominant determinants in the structure of influenza H1 and H5 virus hemagglutinin (HA). In this connection, an EIA, which was based on the competition of influenza A(H5) H5-Ab virus HA-specific MAbs in the test sera for an association with influenza A(H5) virus, was proposed for the subtype-specific detection of H5 Ab. Comparison of the results of competitive EIA (cEIA), microneutralization (MN) test and HA inhibition test (HAIT) (using equine red blood cells) in the examination of sera obtained from 44 volunteers immunized with inactivated vaccine containing influenza A/Indonesia/5/2005 (H5N1) virus showed the high sensitivity and specificity of cEIA in detecting H5-specific Abs. The effectiveness of cEIA for the sera strictly positive for the content of H5 Abs was close to that of MN test and was 9-34% higher than HAIT (depending on those used in the analysis of H5 virus antigens). cEIA may be proposed to assess new influenza vaccines as an additional laboratory test. Since the infectious virus is not used during cEIA, it may be recommended for the serodiagnosis of influenza A(H5) at practical virological laboratories.

[Correlation of p16/INK4a gene damages and protein expression in the tumor tissue of sporadic breast cancer]

A tumor emerges due to the structural and functional abnormalities occurring in the genes, which causes a change in the spectrum of protein molecules. Strong correlations between the gene damages and following changes in the protein spectrum make it possible to study different stages of carcinogenesis and to create a more complete system of molecular markers for the diagnosis of different types of tumors, which comprises protein markers and DNA markers. The present investigation has studied a correlation between the inactivation mechanisms (structural and functional) of the suppressor gene p16/INK4a, which occur at the level of DNA, and the results of its protein expression examined by immunohistochemical methods in the tumor specimens from patients with breast cancer. The investigation could indicate that p16/INK4a gene damage frequently occurred in the tumors of the above type. In the majority of study cases, molecular damages revealed in the gene diminish on its protein expression; however, there are still cases that defy generally accepted explanations.

[Regulatory genes of garden pea (Pisum sativum L.) controlling the development of nitrogen-fixing nodules and arbuscular mycorrhiza: a review of basic and applied aspects]

The review sums up the long experience of the authors and other researchers in studying the genetic system of garden pea (Pisum sativum L.), which controls sthe development of nitrogen-fixing symbiosis and arbuscular mycorrhiza. A justified phenotypic classification of pea mutants is presented. Progress in identifying and cloning symbiotic genes is adequately reflected. The feasibility of using double inoculation as a means of increasing the plant productivity is demonstrated, in which the potential of a tripartite symbiotic system (pea plants-root nodule bacteria-arbuscular mycorrhiza) is mobilized.

[Analysis of the correlation between genetic and immunohistochemical markers (RB1, p16 and p53 gene regultors of a cell cycle) in sporadic mammary gland carcinoma]

The results of an investigation of the RB 1, p16 and p53 genes in sporadic breast cancer through molecular and immunohistochemical studies are presented.

[Algorithm of therapy in neonates with developmental malformations depending on causes and severity of illness in the intensive care unit]

The results of treatment for congenital malformations requiring emergency interventions depend on the timeliness and correctness of diagnosis of a defect, on the performance of resuscitative and surgical interventions, the correct evaluation of a neonate's condition at different stages of treatment. The score rating of the patient's condition is objective and may be an evidence-based medicine tool. Prior to the emergence of the universal scale, many authors used their own developments. On the basis of achievements made by pediatric surgeons, anesthesiologists, resuscitators in the context of statistical analysis, the specific features of neonatology, microbiology, and clinical pharmacology, the authors of the paper have developed a neonatal severity rating scale with inclusion criteria, such as a body weight of more than 2 kg; intensive care unit (ICU) stay, artificial ventilation of at least 2 days of life. Life-threatening periods have been defined in neonatal infants treated at ICU; the main causes of their critical condition have been indicated in certain developmental malformations before and after surgery, the causes of death have been revealed from the material available in their case histories and from morphological charts. The purpose of the present study was to develop an algorithm of therapy for the newborn with severe developmental malformations at ICU and to define a promising line for increasing the survival rates in neonatal infants with these defects.

[Immunoblot for verifying the results of screening of antibodies to hepatitis C virus in blood donors]

A conclusion is made, on the basis of independent research results and published data, on the need to verify, compulsorily, the screening finding of donor blood for hepatitis virus by immunoblot and, in extra complicated cases, by PCR.

The catalytic and photocatalytic oxidation of organic substances using heterogeneous Fenton-type catalysts

This paper deals with catalytic and photocatalytic oxidation of organic substances using H202 over heterogeneous Fenton-type catalysts. In the study a series of Fe-containing catalysts was experienced. A zeolite named as FeZSM-5 was selected as the most active heterogeneous Fenton-type catalyst. The FeZSM-5 reported was prepared by hydrothermal crystallization in the presence of iron salt. In contrast to the homogeneous Fenton system the catalyst prepared had minimal, if any, leaching of iron ions, was stable during 30 catalytic runs and didn't lose its activity in the presence of complexing agents, e.g. P2O7(4-). The catalyst was active in oxidation of organic substances at pH from 1.5 to 8, maximum activity was observed at pH = 3. The FeZSM-5 effectively oxidized a simulant of the warfare agent, diethylnitrophenil phosphate, which is hardly detoxified by other methods. It appeared that the rate of oxidation of formic acid, ethanol and benzene over FeZSM-5 increased under the action of visible light (lambda > 436 nm), quantum efficiency being 0.06-0.14.

Tryptophan synthase from Agrobacterium tumefaciens 8628: isolation and properties

Tryptophan synthase was isolated from a highly virulent strain of Agrobacterium tumefaciens 8628 (octopine type). Separation of tryptophan synthase from thermolabile protease was accomplished using fractionation with polyethylene glycol-6000 followed by ion-exchange chromatography with a pH gradient. Molecular weights of alpha- and beta-subunits are 33 and 51 kD, respectively. The tryptophan synthase is stable at 60 degrees C because of heat-tolerance beta-subunits. After heating the activity of tryptophan synthase increased up to 20 times while temperature-labile proteases lost their activities. Reaction with antibodies showed the presence of four protein bands, one of which was coeluted with nucleic acids during ion-exchange chromatography. It is suggested that the basic tryptophan synthase is encoded by trp genes in a plasmid and its role is to provide the precursor with the prokaryotic pathway of indole-3-acetic acid biosynthesis, which determines the virulence of A. tumefaciens. There is perhaps a cooperation between iaaM, iaaH, and trp genes in the plasmid during plant cell transformation.

[Purine arabinonucleoside-5'-triphosphates with substituents in the 2'-position as DNA polymerase substrates]

Analogues of araNTPs carrying an azido or aminogroup instead of the 2' hydroxyl exhibited substrate properties towards several mammalian and viral DNA polymerases. At the same time, introduction of a bulky hydrophobic DNP group into the 2' position inactivated the compounds as substrates. HSV-1 and CMV DNA polymerases were an interesting exception: they effectively incorporated the modified nucleotide residues with DNP group into the 3'-termini of the DNA chain. This is a reliable way to distinguish these enzymes from cellular DNA polymerases.

Purine arabinonucleoside 5'-triphosphates with substituents at 2' position as substrates for DNA polymerases

Analogues of araNTPs carrying an azido or aminogroup instead of the 2' hydroxyl exhibited substrate properties towards several mammalian and viral DNA polymerases. At the same time, introduction of a bulky hydrophobic DNP group into the 2' position inactivated the compounds as substrates. HSV-1 and CMV DNA polymerases were an interesting exception: they effectively incorporated the modified nucleotide residues with DNP group into the 3'-termini of the DNA chain. This is a reliable distinction of these enzymes from cellular DNA polymerases.

[Reactions of 5'-H-phosphonates, 5'-F-phosphates, and 5'-phosphates of modified thymidines in human blood plasma]

Mechanisms and rates of hydrolytic dephosphorylation of 5'-hydrogen phosphonates, 5'-fluorophosphates, and 5'-phosphates of 3'-azido-3'-deoxythymidine, 3'-fluoro-3'-deoxythymidine, and thymidine in human blood serum were investigated. 5'-Hydrogen phosphonates of 3'-substituted thymidines are dephosphorylated 50-100 times slower than the corresponding 5'-phosphates. 5'-fluorophosphates of 3'-substituted thymidines are dephosphorylated 2 times slower than corresponding 5'-phosphates; first, substituted thymidine 5'-phosphates are formed, which are later dephosphorylated into substituted thymidines. These data illustrate probable molecular mechanisms of anti-HIV action of such nucleotides. 5'-hydrogen phosphonates of thymidines can serve as depot forms of corresponding thymidines, but other metabolic pathways are not excluded. Thymidine 5'-fluorophosphates can serve as depot-forms of both thymidines and their phosphates. Their fate in cells depends probably on their diffusion and on the activities of dephosphorylating and phosphorylating enzymes.

[Conformation of crystalline 3'-nitro-2',3'-dideoxythymidine and properties of its 5'-triphosphate as a terminator substrate of retroviral reverse transcriptase]

The structure of new nucleoside--3'-nitro-2',3'-dideoxythymidine (NIT) possessing moderate anti HIV activity in MT-4 cell culture was investigated by X-ray analysis. These data showed that conformation of NIT in crystal is similar to that of one of crystallographically independent forms of 3'-azido-2',3'-dideoxythymidine. 3'-Nitro-2',3'-dideoxythymidine 5'-triphosphate (NITTP) was synthesized and its ability to inhibit human and viral DNA polymerases was studied. NITTP proved to be effective and highly selective terminating substrate of DNA synthesis catalyzed by HIV and AMV reverse transcriptases. Human DNA polymerase alpha as well as DNA polymerase beta (rat liver), terminal deoxynucleotidyltransferase (calf thymus) or HSV-1 and CMV DNA polymerases did not incorporate NITTP into a growing DNA chain.

[Inhibitory analysis of DNA polymerase of herpes simplex type 1]

The inhibitory potency of new analogs of nucleoside 5'-triphosphates modified at the sugar residue and or alpha-phosphate against herpes simplex virus type 1 DNA polymerase has been evaluated in a cell-free system containing M13mp10 phage DNA and a synthetic primer. Triphosphates of new acyclic nucleosides [1-(5-hydroxy-2-cis-pentenyl)nucleosides] were the most effective inhibitors among 15 types of nucleoside 5'-triphosphates under investigation, being threefold less active than acyclovirtriphosphate. 5'-Phosphonylmethyl-2'-deoxythymidine beta, gamma-diphosphate proved to be a poor substrate for DNA polymerase. Compounds with other modifications at alpha-phosphate were inactive. Constants of hydrolysis rate of acyclonucleosides incorporated into the 3' end of primer were determined.

[Inhibitory analysis of DNA polymerases from human viruses using modified substrates]

A systematic analysis of DNA polymerase of human herpes simplex type 1 virus, cytomegalovirus, and human type 2 adenovirus with the help of a broad set of modified substrates of these enzymes has been carried out. It revealed compounds capable of inhibiting the DNA synthesis catalyzed both by all three enzymes and DNA polymerase alpha from human placenta. Compounds have been found which effectively and specifically inhibit the DNA synthesis catalyzed by some of the abovementioned enzymes. It has been shown that the molecular mechanism of inhibition consists either in the termination of DNA elongation or in inhibition without incorporation into the growing DNA chain.

[5'-S-nucleoside triphosphates. Synthesis and substrate properties in tests with DNA polymerases]

In the course of our investigations on DNA polymerases a synthesis of new triphosphate analogues, 5'-mercapto-5'-deoxythymidine 5'-S-triphosphate and 5'-mercapto-3',5'-dideoxythymidine 5'-S-triphosphate, was brought about starting from 3'-O-acetyl-thymidine and 3'-deoxythymidine, respectively. The former compound proved to be a weak substrate for E. coli DNA polymerase I and AMV reverse transcriptase and inactive towards DNA polymerases alpha from placenta and beta from rat liver. The second synthesized triphosphate was incorporated into DNA chain by none of the tested enzymes. Probable reasons for so strong a decrease in the substrate properties of the prepared compounds are discussed.

Molecular hybridization with DNA probes as a laboratory diagnosis test for influenza viruses: further investigations on the possibilities of the method

The possibilities of the molecular hybridization test, i.e. test, i.e. using neuraminidase probes of different subtypes for subtype specific detection of influenza, as well as different probes (PA, M, NP) for type A specific detection of influenza viruses in infected cells were shown. The results of molecular hybridization in washings' analyses from patients during the outbreaks give us an opportunity to make some conclusions about the usefulness of the method in epidemic control of influenza morbidity.

[Molecular hybridization of nucleic acids as a method for the laboratory diagnosis of influenza in model experiments on cell cultures and in research on nasopharyngeal smears obtained from patients]

DNA probes containing the nucleotide sequences of the conservative genes of influenza A virus (matrix, nucleoprotein and acidic polymerase genes) show their specificity with respect to the RNA of influenza A viruses in mammal tissue cell cultures (continuous spaniel kidney cell culture and primary calf kidney cell culture). The minimal amount of infected monolayer cells, permitting the detection of viral RNA, is 10(3). The results obtained in the study of nasopharyngeal washings make it possible to recommend the method of molecular hybridization for use in the epidemiological analysis in addition to virological and serological tests. The method of hybridization permits the detection of virus-specific RNA in the allantoic fluid of chick embryos in subculturing the materials under study even in those cases when hemagglutinating influenza virus cannot be isolated.

[Effect of bacterial DNA gyrase inhibitors on the radiosensitivity of thymocytes and on the utilization of exogenous adenine in these cells]

It was established that the postirradiation changes in incorporation of 14C-adenine into acid-soluble and acid-insoluble fractions of thymocytes reflected cell death. When added after irradiation, nalidixic and oxolinic acids exerted a radioprotective action. The effect was absent after single washing of thymocytes incubated with these compounds for 60 min before or after irradiation. Both substances inhibited utilization of 14C-adenine and incorporation thereof into the acid-insoluble fraction of nonirradiated thymocytes and did not influence the viability of cells.

[Postradiation disorders in the adenine-phosphoribosyltransferase pathway of AMP biosynthesis]

A study was made of the activity of adenine-phosphoribosyltransferase (EC 2.4.2.7), which catalizes the biosynthesis of AMP from adenine and 5-phospho-alpha-D-riboso-1-diphosphate, in extracts from thymus and liver during 24 h following irradiation of mice in a dose of 245.1 mC/kg (dose-rate of 9.16 X 10(-4)-9.0 X 10(-4) A/kg). Adenine-phosphoribosyltransferase activity of liver remains normal during the entire period of observation. In thymus extracts, the activity of the enzyme decreases down to 70-80% of the control level 3 h after irradiation, it is normalized after 6 h and increases up to 150-160% of the control level by the end of the first day of radiation sickness.

Comparative studies on influenza B virus. II. The effect of host cells on biological properties and polypeptide composition

The reproduction patterns of various influenza B virus strains isolated in 1970-1976 using roller cultures of MDCK cells and chick embryos (CE) were compared. The cultural and allantoic virus populations did not differ in their sensitivity to non-specific inhibitors from mammalian sera and in their reactivity with specific haemagglutinins (HA). The content of infectious virus and HA in the harvested allantoic fluids as compared to medium fluids were 94- and 8-fold higher, respectively, even though the fluids did not differ in the titres of complement-fixing (CF) antigen. The mol. weight (MW) of HA1 polypeptide of the B/Len/75 virus prepared in culture was higher than that Of the allantoic virus (57.5 K and 55.5 K, respectively). Under reducing conditions, the HA of the virus from culture was represented mostly by the uncleaved HA0 polypeptide, while that of the allantoic virus by the HA1 and HA2 subunits. Under non-reducing conditions, the virus from medium fluid was found to contain glycopeptide D with MW of 90 K.

Comparative studies on influenza B virus. I. Biological properties and polypeptide composition of strains isolated in different years

Influenza B viruses isolated in 1940, 1950 and 1970 belonged to antigenically remote subgroups according to the antigenic composition of haemagglutinin (HA). Antigenically related strains isolated in 1972-1976 differed by their reproduction capability, by their sensitivity to inhibitors in mammalian sera and by affinity to specific antibodies in human sera. Certain correlation between these properties was observed by strains of the Hong Kong variant. Polyacrylamide gel electrophoresis (PAGE) showed that the viruses under study differed in the mobility of the major HA chain (HA1). Molecular weights (MW) of HA1 of antigenically similar influenza B viruses isolated in 1972-1976 revealing different biological properties varied from 52.5 K to 58 K. Neuraminidase (NA) of influenza B/Leningrad/369/75 virus purified by electrophoresis in acetate cellulose consisted of 2 polypeptides with apparent MW of 62 K and 57 K. All viruses examined showed similar mobility of the NA polypeptide MW 57 K; the mobility of the former polypeptide was similar to that of nucleoprotein (NP).