Increasing the Hydration Activity of Tricalcium Silicate by Adding Microdispersed Ettringite as a Nucleating Agent

Tricalcium silicate (C3S) as a binder material has a decisive influence on the processes of hardening and strength gain of cements and concretes. One of the promising directions is the introduction of dispersed additives into cement mixtures, which allow micro-level control of the composition of hydration products and change the dynamics of the structure formation of cement stone. In this paper, the effect of a microdisperse ettringite additive on the kinetics of the hydration and hardening process of tricalcium silicate was studied. It was shown that ettringite crystals selectively adsorb Ca2+ and OH- ions from a saturated solution of calcium hydroxide, which contributes to the formation of hydrosilicate nuclei on their surface during cement hydration. Hydration of C3S in the presence of ettringite proceeds more intensively; the addition of ettringite contributes to an increase in the content of calcium hydrosilicates in hydration products at the initial stage of the process. Addition of 10 wt.% ettringite to C3S reduces the induction period of the beginning of the main phase of heat release by around two times and increases the amount of heat released on the 1st day of hydration by 15% compared to the control sample. According to electron microscopy data, it was found that during the first hours of hydration of modified C3S, a significant number of nuclei of fibrous particles of calcium hydrosilicates with sizes of 0.2-2 microns were formed on the surface of ettringite crystals. According to the results of kinetic modeling of the setting process of cement pastes using the Avrami-Erofeyev model, it was shown that in the presence of the addition of microcrystals of ettringite, the setting rate is characterized by a slowdown in nucleation, whereas for a sample without an additive, this process proceeds with an acceleration of the formation of solid-phase nuclei. Based on the comparison of kinetic results and mechanical measurements, it is concluded that needle crystals of ettringite during C3S hydration and cement stone hardening are preformed centers for the growth of hydrosilicate nuclei, and they also act as a reinforcing filler, increasing the bending strength of modified samples. The results of the work can be used in practice in the development of methods for controlling the processes of hydration and hardening of cements, as well as for controllable structure formation of cement stone which is important in particular for 3D printing of building products and constructions.

Synthesis and Evaluation of Properties of an Additive Based on Bismuth Titanates for Cement Systems

The development of modern building materials science involves the process of designing innovative materials that exhibit unique characteristics, such as energy efficiency, environmental friendliness, self-healing ability, and photocatalytic properties. This can be achieved by modifying cement with nano- and fine-dispersed additives that can give the material new properties. Such additives include a number of compounds based on the TiO2-Bi2O3 system. These compounds have photocatalytic activity in the near-UV and visible range of the spectrum, which can serve to create photocatalytic concretes. Here, the purpose of this scientific study was to synthesize compounds based on the TiO2-Bi2O3 system using two methods in order to identify the most optimal variant for creating a composite material and determine its properties. Within the framework of this article, two methods of obtaining a photocatalytically active additive based on the TiO2-Bi2O3 system are considered: the solid-state and citrate-based methods. The photocatalytic, mechanical and structural properties of composites containing the synthesized additive are investigated. In this study, it was found that for the creation of photocatalytic concretes, it is advisable to use cement compositions with a bismuth titanate content of 3-10 wt.%. of the cement content, regardless of the method of obtaining the additive. However, the most optimal composition is one containing 5 wt.% of the synthesized additive. It is noted that compositions containing 5% by weight of bismuth titanate demonstrate photocatalytic activity and also show an increase in strength on the first day of hardening by 10% for the solid-state method and 16% for the citrate method.

The Baikal subtype of tick-borne encephalitis virus is evident of recombination between Siberian and Far-Eastern subtypes

Tick-borne encephalitis virus (TBEV) is a flavivirus which causes an acute or sometimes chronic infection that frequently has severe neurological consequences, and is a major public health threat in Eurasia. TBEV is genetically classified into three distinct subtypes; however, at least one group of isolates, the Baikal subtype, also referred to as “886-84-like”, challenges this classification. Baikal TBEV is a persistent group which has been repeatedly isolated from ticks and small mammals in the Buryat Republic, Irkutsk and Trans-Baikal regions of Russia for several decades. One case of meningoencephalitis with a lethal outcome caused by this subtype has been described in Mongolia in 2010. While recombination is frequent in Flaviviridae, its role in the evolution of TBEV has not been established. Here, we isolate and sequence four novel Baikal TBEV samples obtained in Eastern Siberia. Using a set of methods for inference of recombination events, including a newly developed phylogenetic method allowing for formal statistical testing for such events in the past, we find robust support for a difference in phylogenetic histories between genomic regions, indicating recombination at origin of the Baikal TBEV. This finding extends our understanding of the role of recombination in the evolution of this human pathogen.

[Modern achievements in the diagnosis and treatment of glaucoma]

Glaucoma is one of the most difficult and significant ocular conditions. The chronic asymptomatic course of glaucoma progression leads to irreversible deterioration of visual functions. Many aspects of its pathogenesis, the features of its clinical presentation, diagnosis and treatment have been identified in recent years. The results of diagnostic methods: tonometry, perimetry, optical coherence tomography - with glaucoma do not have high specificity due to the large diversity of the population. When determining the target intraocular pressure (IOP), we look at the indicators of the choroidal blood flow and biomechanical stress of the cornea and sclera (fibrous membrane of the eye). Studying visual functions is important in the diagnosis and monitoring of glaucoma. The creation of a modern portable device based on a virtual reality helmet allows examination of patients with low central vision. Structural changes in glaucoma affect the optic disc and the inner retinal layers. The proposed classification of atypical discs allows determining the earliest characteristic changes in the neuroretinal rim for glaucoma in cases of difficult diagnosis. The complexity of the diagnosis of glaucoma is also associated with concomitant pathologies in elderly patients. In cases with comorbidity of primary glaucoma and Alzheimer's disease the structural and functional changes revealed by modern research methods for glaucoma are explained by both the process of secondary transsynaptic degeneration and the death of neurons as a result of an increased IOP. The starting treatment is and its type are fundamentally important for preserving visual functions. Drug therapy with prostaglandin analogues contributes to a significant and persistent decrease in the level of IOP, and mainly by utilizing the uveoscleral outflow pathway. Surgical treatment of glaucoma is an effective way to achieve the target IOP values. However, postoperative hypotension affects the bloodstream both in the central and peripapillary retina. Optical coherence tomography angiography helped establishe that the strongest factor that determines postoperative changes is the difference in IOP, not its absolute level.

[Comparative evaluation of hypotensive effectiveness of topical monotherapy and selective laser trabeculectomy]

PURPOSE

Comparison of the hypotensive effects of selective laser trabeculoplasty (SLT) and drug therapy in patients with newly diagnosed primary open-angle glaucoma (POAG) and ocular hypertension.

MATERIAL AND METHODS

Thirty patients (30 eyes) with newly diagnosed ophthalmic hypertension or POAG were observed. Patients of the 1st group (15 eyes) underwent standard SLT as a starting treatment, patients of the 2nd group (15 eyes) were prescribed monotherapy with a prostaglandin analog. Corneal compensated intraocular pressure (IOPcc) was measured for each patient using Ocular Response Analyzer («Reichert Technologies», USA). The observation period lasted 6 months.

RESULTS

During the 6-months follow-up, tafluprost was found to effectively reduce IOP in 93.3% of cases, SLT - in 73.3% of cases. There were no statistically significant differences in hypotensive effectiveness between the two compared treatments, which amounted to 27.9-28.5% reduction from the baseline values.

CONCLUSION

Selective laser trabeculectomy and topical drug therapy have shown similar hypotensive effectiveness during the 6-months follow-up when used as the initial therapy for POAG.

The genetic determinants of Mycobacterium leprae resistance to antimicrobial drugs

The review is devoted to the appearance of resistance of a slowly developing disease leprosy to antimicrobial therapy (AMP), primarily recommended by the World Health Organization. The main danger of drug resistant leprosy is in the difficulty of identifying, since the causative agent of the disease is not cultivated on artificial media, and the methods for diagnosing drug resistance that are currently used take a long time. The drug resistance of the Mycobacterium leprae strain even to individual components of combination drug therapy result to the development of symptoms of the disease despite undergo anti-leprosy therapy, which in turn can cause the patient to become disabled. Currently, in the Russian Federation, there is no approved test for detecting Mycobacterium leprae DNA, and the determination of genetic determinants of resistance is carried out by sequencing genome regions determined by WHO recommendations: small gyrA, folP and rpoB genes loci. At the same time, modern studies in endemic regions reveal an increased level of Mycobacterium leprae strains resistant to individual components of combined drug therapy. The use of next generation sequencing (NGS) has made it possible to identify additional genetic determinants of leprosy resistance to the components of combination drug therapy. The current situation is relevant to antimicrobal drug resistance surveillance by using of quick identification systems for most frequent genetic resistance determinants of Mycobacterium leprae. The literature search was carried out using keywords in the Scopus, PubMed and RSCI databases.

[Coefficient of biomechanical stress in assessment of the degree of intraocular pressure compensation]

Intraocular pressure is the one modifiable factor, which correct assessment and normalization initiates the treatment of glaucoma. The accuracy of its measurement by traditional methods depends on biomechanical properties of the fibrous tunic of the eye, which in modern clinical practice are most successfully studied by the method of bidirectional applanation of the cornea using the Ocular Response Analyzer (ORA). Mathematical integration of the parameters it measures makes it possible to calculate the coefficient of biomechanical stress (K_bs) that characterizes changes in the fibrous tunic of the eye induced by intraocular pressure, and serves as a criterion for intraocular pressure compensation.

PURPOSE

To determine the range of normal values of the K_bs coefficient, and to evaluate its specificity and sensitivity as a criterion for the degree of intraocular pressure compensation.

MATERIAL AND METHODS

Two consecutive studies on representative clinical material were used to determine the range of normal K_bs values in patients without significant ophthalmic pathologies (400 patients, 800 eyes) and establish the sensitivity and specificity of the coefficient in the diagnosis of glaucoma in patients with newly diagnosed glaucoma (673 patients, 1346 eyes). The age and gender composition of patients in both study groups was similar.

RESULTS

The cut-off value for K_bs is 1.0. In the range of values from 1.0 to 1.09, additional risk factors for glaucoma progression must be taken into account to assess intraocular pressure compensation. In cases when K_bs is equal to or exceeds 1.1, the intraocular pressure is considered elevated and a high risk of disease development or progression is predicted. In glaucoma patients with uncompensated intraocular pressure, the specificity of K_bs is 81.5%, the relative specificity (including the borderline range) is 98%. With K_bs values over 1.1, its specificity reaches 100%.

CONCLUSION

The performed clinical and statistical analysis demonstrates high sensitivity and specificity of the biomechanical stress coefficient in the diagnosis and treatment of glaucoma.

Osteosarcopenia in chronic pancreatitis

Aim. To determine clinical features and some mechanisms of osteosarcopenia development in patients with chronic pancreatitis (CP). Materials and methods. A casecontrol study was conducted on the basis of the Saratov State Clinical Hospital 5 in 20152018 of patients with CP. In a study of 161 patients with CP included, the control group 30 healthy individuals. Patients were divided into groups according to the etiology of CP: 79 with toxic-metabolic CP, 82 with biliary CP. To determine the risks of low-energy fractures, 154 patients were tested with the Fracture risk assessment tool (FRAX). Along with the standard examination, 30 patients with CP dual-energy X-ray absorptiometry was performed. To assess the state of skeletal muscles, body mass index was determined, hand-held dynamometry was performed, and a set of Short Physical Performance Battery (SPPB) tests was used. Along with the assessment of traditional risk factors for osteosarcopenia gender, age, state of reproductive function in women, body mass index, functional state of the pancreas (pancreas) the quantitative content of interleukins (IL)-2, 6, 8 in in colonic biopsies was analyzed by enzyme-linked immunosorbent assay (ELISA). Results. Bone disorders, according to densitometry, was detected in 70.0% of patients with CP, in 13.3% of the control group. Presarcopenia was detected in 62 (38.5%) patients with CP, sarcopenia in 34 (21.1%), in the control group presarcopenia and sarcopenia were not detected. Sarcopenia was statistically significantly more common in toxic-metabolic CP than in biliary CP (2=11.6; p0.001). Correlations of the lumbar spine T-score and IL-6 (r=-0.29; p=0.03), IL-8 (r=-0.29; p=0.04) were revealed. Correlations between sarcopenia and the concentration of cytokines in the in the colon mucosa in CP were determined (IL-2: r=0.44; p0.001; IL-6: r=0.48; p0.001; IL-8: r=0.42; p0.001). Conclusion. The development of osteopenia and sarcopenia syndromes in CP is interrelated and associated with both traditional risk factors and an increased concentration of cytokines in the in the colon mucosa.

[Thermography of ocular surface tissues in the assessment of aseptic postoperative inflammation]

PURPOSE

To determine the thermographic parameters of ocular surface tissues in various types of anti-glaucoma operations.

MATERIAL AND METHODS

The study included 70 patients with glaucoma (140 eyes) and 28 patients (56 eyes) with cataract and planned phacoemulsification. All patients underwent dynamic infrared thermography of the eye surface to evaluate the aseptic inflammatory response before and after surgery.

RESULTS

The increase in the temperature of the ocular surface tissues was longer after penetrating glaucoma surgery than after the non-penetrating type, which indicates a more prolonged inflammatory aseptic reaction in response to surgical intervention.

CONCLUSION

The obtained results allow the development of a rational tactic of preoperative drug preparation and more effective postoperative management.

[Frequency and type of macular edema after cataract surgery in patients with glaucoma]

Cataract is one of the common causes of reversible vision loss in people older than 50 years. Currently, the only way to treat it effectively is phacoemulsification with simultaneous implantation of an intraocular lens - a method that minimizes the amount of surgical trauma and the number of intra- and postoperative complications. Nevertheless, the problem of prevention and timely diagnosis of pathological changes in the retina, which may develop after extraction of cataracts, and in particular - macular edema, remains relevant. This problem becomes especially important when it comes to patients with concomitant cataract and glaucoma who use local antihypertensive drugs - in particular, prostaglandin analogues - for a long time. Having common properties with inflammatory mediators, in some cases they can cause vasodilation, increase vascular permeability and contribute to the development of exudative processes. Drugs of this group can cause impairment of the hematophthalmic and hematoretinal barriers provoking the development of cystoid macular edema, including in the early postoperative period after cataract extraction. As described by S. Irvine in 1953, macular edema is related to late postoperative complications and remains one of the main causes of visual impairment after lens removal. The review provides information about some studies concerning the effect of prostaglandin derivatives on the postoperative period after phacoemulsification. At this time, there is no consensus on this matter.

Genetic diversity and geographical distribution of the Siberian subtype of the tick-borne encephalitis virus

The tick-borne encephalitis virus (TBEV), a member of the Flaviviridae family, is currently subdivided into three main subtypes-the European (TBEV-Eu), the Far-Eastern (TBEV-FE), and the Siberian (TBEV-Sib). The TBEV-Sib is the most common subtype and found in all regions where TBEV was detected, except for Central and Western Europe. Currently, four genetic lineages have been described within TBEV-Sib. In this study, detailed analysis of TBEV-Sib genetic diversity, geographic distribution, phylogeography and divergence time of different TBEV-Sib genetic lineages based on E gene fragments, complete genome sequences, and all currently available data in the GenBank database was performed. As a result, a novel Bosnia lineage within the TBEV-Sib was identified. It was demonstrated that the Zausaev lineage is the most widely distributed among the TBEV-Sib lineages, and was detected in all studied regions except the Far East. The Vasilchenko lineage was found from Western Siberia to the Far East. The Baltic lineage is presented from Europe to Western Siberia. The Obskaya lineage was found only in Western Siberia. TBEV strains from a newly described Bosnia lineage were detected in Bosnia, the Crimean peninsula, Kyrgyzstan and Kazakhstan. The greatest divergence of the TBEV-Sib genetic variants was observed in Western Siberia. Within the TBEV-Sib, the Obskaya lineage diverged from the common ancestor the earliest, after that the Bosnia lineage was separated, then the Baltic lineage, and the Zausaev and Vasilchenko lineages diverged most recently.

[Dynamics of changes in morphometric parameters of the macular zone in glaucoma patients after phacoemulsification]

PURPOSE

To analyze the dynamics of morphometric changes in the macular zone using optical coherence tomography (OCT) data in patients with primary open-angle glaucoma (POAG) after phacoemulsification (PE).

MATERIAL AND METHODS

The study enrolled 93 patients (95 eyes) requiring PE; they were divided into 2 groups. The first (control) group consisted of 30 patients (32 eyes) without concomitant eye pathology. The second group included 63 patients (64 eyes) with POAG and IOP stabilized by eye drops. In the 2A subgroup (32 eyes) patients used prostaglandin analogues, in the 2B subgroup (31 eye) - carbonic anhydrase inhibitors. OCT was used to analyze retinal thickness and volume. OCT was performed before PE, after 1 week, after 1, 3, and 6 months.

RESULTS

In the control group, the volume and thickness of the retina varied within the normal range. In the 2A subgroup, signs of macular edema (ME) in the early post-operative period were noted in 6.2% of patients. In the late post-operative period, changes in the macular zone were noted in 18.7% of cases. After the treatment, ME regressed completely in 4 patients (12.5% of all cases). One patient with retinal thickness of more than 500 µm required parabulbar and intravenous injections of glucocorticoids, which resulted in ME decrease. Another patient developed epiretinal fibrosis with tractions after ME. Among the patients of subgroup 2B, a trend for increase in the volume and thickness of the macular zone was observed in 3 cases; the values stayed within the normal range, and later returned to the initial level.

CONCLUSION

Patients with POAG develop ME after PE in 1-3 months. The use of topical prostaglandin analogues may be the reason of ME development.

[New Genetic Marker of Human Predisposition to Severe Forms of Tick-Borne Encephalitis]

The causative agent of tick-borne encephalitis (a neurotropic RNA virus from the Flavivirus genus) can cause both severe paralytic forms of the disease (meningoencephalitis, etc.) and milder nonparalytic forms (fever and meningitis). The organism response to viral infection (and, as a consequence, the nature and outcome of the disease) significantly depends on individual peculiarities of the human organism protective systems predetermined by genome structure. Human genetic predisposition to tick-borne encephalitis has been poorly studied. In the present work, the results of the search for new genes that predetermine the peculiarities and outcome of tick-borne encephalitis in humans are presented. The aim of the work was to verify the association between three previously detected (using the exome sequencing on a limited sample of tick-borne encephalitis patients with severe forms) SNPs: intronic rs3109675 (C/T) in the COL5A1 gene, intronic rs41554313 (A/G) in the POLRMT gene, and intergenic rs10006630 (C/A), and the predisposition to tick-borne encephalitis in a Russian population (using an extended sample of patients with different forms of tick-borne encephalitis). The association of the rs10006630 SNP located in chromosome 4 between the FABP2 and LINC01061 genes with a predisposition to tick-borne encephalitis was confirmed. This SNP can be considered as a new genetic marker of a human predisposition to severe forms of tick-borne encephalitis. The possible regulatory role of this SNP in the functioning of neighboring genes and a mechanism of its effect on the development of predisposition to severe forms of tick-borne encephalitis require further study.

[Hypotensive efficacy of bimatoprost in monotherapy of primary open-angle glaucoma]

PURPOSE

To study the effectiveness of monotherapy with bimatoprost in patients with decompensated intraocular pressure (IOP).

MATERIAL AND METHODS

90 patients (132 eyes) with stage I-II glaucoma and decompensated IOP previously treated with timolol, latanoprost and travoprost were included in the study. Average IOP at the beginning of the study was 25.4±2.5 mmHg. All patients had their hypotensive medications substituted by bimatoprost. The patients were examined during the initial appointment, as well as after 4 and 12 weeks.

RESULTS

IOP decrease was highest in the group of patients who had been treated with timolol: initially IOP was 26.2±1.8 mmHg, after 4 weeks - 21.0±2.2 mmHg, after 12 weeks - 20.8±1.9 mmHg (p<0.001). The initial IOP of patients who had been treated with latanoprost was 24.8±2.9 mmHg, 21.8±2.4 mmHg after 4 weeks, and 21.6±2.3 mmHg after 12 weeks (p<0.001). Patients who had been treated with travoprost had 25.6±2.2 mmHg initially, 23.0±2.5 mmHg after 4 weeks, and 23.2±2.6 mmHg after 12 weeks (p<0.001). By the end of the study IOP has decreased by 5.4, 3.2 and 2.4 mmHg in the groups of patients who had been treated with timolol, latanoprost and travoprost, respectively.

CONCLUSION

Bimatoprost can be used as monotherapy if another hypotensive drug in monotherapy is insufficient for IOP compensation.

[Optimization of therapy for hepatobiliary disorders in psoriatic patients]

AIM

To optimize management tactics in patients with diseases of the liver and gallbladder in the presence of progressive psoriasis.

SUBJECTS AND METHODS

The investigation enrolled 78 patients with nonalcoholic fatty liver disease (NAFLD) and different forms of gallbladder abnormality in the presence of progressive moderate and severe psoriasis. The patients were randomly divided into 2 groups: 1) phosphogliv; 2) ursosan with the main active ingredient ursodeoxycholic acid (UDCA). A prospective follow-up study accompanied by dynamic clinical, laboratory, and instrumental monitoring was carried out for 24 weeks. Clinical, biochemical, and ultrasound studies, including liver elastography, were applied.

RESULTS

The use of UDCA (Ursosan 15 mg/kg for 24 weeks) to treat NAFLD and gallbladder abnormality in methotrexate-treated patients with progressive moderate and severe psoriasis contributed to the normalization of hepatic steatosis index, lipid composition, and lithogenic index, to the reduction of biliary sludge, and to the stabilization of liver fibrosis. Improvement in the functional status of the liver and gallbladder has contributed to the achievement of a more complete remission of dermatosis.

CONCLUSION

The effects of UDCA in the therapy of NAFLD and gallbladder abnormality in patients with progressive psoriasis were greater than those of phosphogliv.

DEFINITION AND COMPARATIVE ANALYSIS OF THE GENOMIC STRUCTURE OF SIBERIAN STRAINS OF TICK-BORNE ENCEPHALITIS VIRUS OF THE EUROPEAN SUBTYPE

Tick-borne encephalitis virus (TBEV) is classified into three subtypes: Far Eastern (TBEV-FE), European (TBEV-EU) and Siberian (TBEV-SIB). In Russia, these are also called genotypes 1, 2 and 3, respectively. Geographically, TBEV-EU dominates in Central and Northern Europe, but its representatives are also found to the east - along the southern part of the forest zone of extratropical Eurasia - up to Eastern Siberia and South Korea. However, the strains isolated outside Europe remain poorly investigated. In the proposed study, eight full genomes of the Siberian isolates of TBEV-EU were determined and 13 complete genomes were compared. The analysis of 152 full-genome TBEV sequences showed that the TBEV-EU has a higher degree of stability of the genome-coding region in the entire Eurasian area (3.1% of differences) compared to TBEV-FE (6.6%) and TBEV-SIB (7.8%). At the same time, the maximum differences are observed not between European and Siberian strains, as one could expect, but between the representatives from Europe - TBEV strains Mandl-2009 from Norway and Hypr from the Czech Republic. The studied strains from Siberia form the compact genetic cluster of 42 TBEV-EU strains and are divided into two subclusters - West Siberian and East Siberian variants. These variants differ in the combinations of amino acid substitutions in all proteins except NS2B. The West Siberian variant mostly circulates in the territory of Altai, and the closest relative of its representatives is Absettarov strain from the European part of Russia. The strains similar to the East Siberian variant of the European subtype were recorded in the Altai (strain 84.2, 2007) and in Belarus (N256, about 1940).

[Dynamics of electrophysiological parameters of the retina after surgical treatment of idiopathic macular hole]

AIM

to study the dynamics of recovery of electrophysiological parameters of the retina after surgical treatment of idiopathic macular hole (IMH) and to assess their relevance to functional prognosis of the operation.

MATERIAL AND METHODS

The study included 118 patients (120 eyes) examined before and after successful IMH surgery. The patients underwent electroretinography (Ganzfeld and multifocal), static computed perimetry, and optical coherence tomography. They were also tested for the electrical sensitivity of the retina, lability of the visual analyzer, and critical fusion frequency. Postoperative functional parameters of the retina (electrophysiological included) were followed up at 1-2, 5-6, and 12-plus months and then compared to those obtained before surgery. Parameter dynamics, relationships, and the prognostic value of particular indicators were of interest.

RESULTS

It was found that after successful restoration of retinal anatomy, functional parameters of the retina gradually improve and reach their maximum at 3 to 12 months, however, remain below the normal range in all cases. In 58 cases, postoperative visual acuity was 0.5 or higher (regarded as 'high postoperative visual acuity' - the HPVA group) and was accompanied by high density of foveal biopotential and foveal light sensitivity. In the HPVA group, the majority (62%) were patients with preoperative 'shift phenomenon' (a shift of the maximum of bioelectric potential from the fovea to parafovea and perifovea, its amplitude and density being supernormal for these retinal regions).

CONCLUSION

Changes in electrophysiological and other functional parameters of the retina can be detected within 3-12 months after successful IMH surgery. Their recovery is not full and goes with a delay relative to restoration of retinal structure. The probability of high functional result of the operation, which includes an increase in visual acuity, foveal light sensitivity, and amplitude and density of foveal biopotential, is higher in patients with biopotential shift at baseline.

[Electrophysiological parameters of the retina in idiopathic macular hole]

AIM

To investigate the nature and range of electrophysiological disturbances in idiopathic macular hole (IMH) and establish their relationship with structural parameters of the retina.

MATERIAL AND METHODS

The study included 249 patients (280 eyes) with IMH. All of them underwent ganzfeld and multifocal electroretinography (ERG), optical coherence tomography, and evaluation of retinal electrical sensitivity and analyzer lability. The results were then compared to those of non-IMH patients (196 paired eyes) and controls (25 people, 49 eyes).

RESULTS

Multifocal ERG findings prove that IMH is always associated with significant changes in bioelectrical potential of the central retina. In 62% of cases its decreased density and extended latency were registered in not only the fovea, but also the para- and perifovea. In 8% of cases the changes involved everything within a 30-degree area of the central retina. In 30% of cases the maximum bioelectric potential was found to have shifted from the centre to para- and perifovea, its amplitude and density being supernormal for these regions (shift phenomenon). A weak correlation between electrophysiological parameters and retinal thickness around the hole has been also established.

CONCLUSION

Of all methods used to assess retinal function in IMH, multifocal ERG is the most informative. In 100% of cases foveal biopotential is sharply reduced in density and disfigured. In 70% of cases these changes spread outside the fovea.

MECHANISMS OF DEVELOPMENT AND CHARACTERISTICS THE PATHOLOGY OF THE GASTROINTESTINAL TRACT IN CHRONIC PANCREATITIS

The review deals with the mechanisms of the clinical features and pathology of the gastrointestinal tract in chronic pancreatitis.

[CANDIDIASIS GASTROINTESTINAL TRACT]

This review covers the epidemiology, pathogenesis, risk factors, classification, clinical manifestations of candidiasis gastrointestinal, diagnosis and therapies.

Influence of altitude on tick-borne encephalitis infection risk in the natural foci of the Altai Republic, Southern Siberia

The Altai Republic is a highly endemic area as far as tick-borne encephalitis (TBE) is concerned. The aim of the research was to study the effect of altitude on the risk of tick-borne encephalitis infection in the Altai Republic. The paper analyzes the following data: the study of ixodid ticks collected from the vegetation in 116 sites at the 200-2383m elevation above sea level in 2012-2014, TBE virus prevalence of these vectors, tick-bite incidence rate, and TBE incidence rate of the population. Species identification of 4503 specimens has shown that the most common species are Dermacentor nuttalli (45.3%), Ixodes persulcatus (33.1%), Dermacentor silvarum (9.4%), Dermacentor reticulatus (8.9%), and Haemaphysalis concinna (5.0%). A total of 2997 adult ixodid ticks were studied for the presence of the TBE virus; 2163 samples were examined by ELISA, while 834 specimens were tested by PCR. The TBE virus prevalence of Dermacentor spp. ticks in both reactions was significantly higher than of Ixodes persulcatus ticks (p<0.001). The work shows that the altitude is an important factor in the development of the epidemiological situation of tick-borne encephalitis: the higher the elevation of the area above sea level, the smaller the range of vectors. There is also a change of a leading species: in middle altitude (800-1700m above sea level) the virus is transmitted by ticks of D. nuttalli along with I. persulcatus, and in high mountains (above 1700m above sea level) D. nuttalli becomes an absolute dominant species. However, these species of ticks are less effective vectors than I. persulcatus. With the increase of altitude the tick-bite incidence rate decreases (r=-0.78, p<0.05), and TBE incidence also reduces (r=-0.67, p<0.05).

[Eosinophilic esophagitis in adults: current approaches to diet therapy]

The review describes the basic strategy of eosinophilic esophagitis diet therapy in adult patients: elemental diet, allergy testing-directed food elimination diet and empirical elimination diet. The review includes information about the effects of different methods of diet therapy on the severity of eosinophilic infiltration of the esophageal mucosa and symptoms of eosinophilic esophagitis.

[Detection of potential sites of recombination in the Tick-borne encephalitis virus by the methods of comparative genomics]

The results of the bioinformatic search for the potential sites of the recombination in the genome-wide structures of the tick-borne encephalitis virus (TBEV) through a series of software techniques were presented in this work. The genomes of the 55 TBEV strains were assayed, 21 of them showed the presence of the recombination sites. Recombinant strains belonged to the Far Eastern (19 strains) and European (2 strains) genotypes. 22 sites of the recombination attributed were identified to five types based on position, strain, and regional characteristics. The parental strains were identified based on the genotypic and geographical parameters, which do not contradict the possibility of the formation of the recombinants. Nearly two-thirds of the sites are located in the regions of NS4a and NS4b genes, which are the "hot spots" of the recombination, most of them being concentrated in the gene NS4. It was shown that the recombination processes did not occur at the level of the genotypes (European genotype) or certain groups within the genotype (Far East) and were typical of the peripheral populations.

[Comorbidity of diseases of the liver, biliary tract and psoriasis]

MATERIALS AND METHODS

Groups of patients with various forms of psoriasis are investigated: with a widespread dermatosis in a progressing phase; group of comparison was consisted of patients with a local dermatosis. Clinical, biochemical, ultrasonic methods of research of a liver and a bilious ways, duodenal sounding are applied.

RESULTS

Aberrations of functional tests of a liver, pathology of a biliarny path, violation of a lipidic exchange, laboratory and tool symptoms of fibrosis were reliable more often at patients with widespread psoriasis, than patients with a local form of a disease.

CONCLUSION

The widespread form of psoriasis is associated with non alcoholic fatty disease of a liver and big frequency of diseases of bilious ways. Results of researches need to be considered when carrying out basic therapy of widespread psoriasis.

[THE MODERN PATIENT WITH A GASTROENTEROLOGICAL DISEASE: ADDITION TO A CLINICAL PORTRAIT]

The typical features of patients with gastroenterology pathology, which have no nosological specificity were analysed: initially chronic course of diseases, combination of diseases, personal features with prevalence of depressions and frustration, an allergization, increase in frequency of a metabolic syndrome and a chronic focal infection.

Genetic variability of Babesia parasites in Haemaphysalis spp. and Ixodes persulcatus ticks in the Baikal region and Far East of Russia

To study Babesia diversity in Ixodid ticks in Russia, Ixodes persulcatus, Haemaphysalis japonica, Haemaphysalisconcinna, Dermacentor silvarum, and Dermacentor nuttalli ticks collected in the Far East and Baikal region were assayed for the presence of Babesia spp. using nested PCR. In total, Babesia DNA was detected in 30 of the 1125 (2.7%) I. persulcatus, 17 of the 573 (3.0%) H. concinna, and 12 of the 543 (2.2%) H. japonica but was undetectable in any of the 294 analyzed Dermacentor spp. Partial 18S rRNA gene sequences were determined for all of the positive samples. Among the positive ticks, nine I. persulcatus were infected by Babesia microti 'US'-type, five I. persulcatus were infected by Babesia divergens-like parasites, and 11 I. persulcatus were infected by Babesia venatorum. For all three of these species, the determined 18S rRNA gene sequences were identical to those of the Babesia genetic variants found previously in I. persulcatus in Russia. In addition, five I. persulcatus from the Baikal region and all of the positive Haemaphysalis spp. ticks carried 13 different sequence variants of Babesia sensu stricto belonging to distinct phylogenetic clusters. Babesia spp. from 29 ticks of different species collected in distinct locations belonged to the cluster of cattle and ovine parasites (Babesia crassa, Babesiamajor, Babesiamotasi, Babesiabigemina, etc.). Babesia spp. from four H. japonica ticks in the Far East belonged to the cluster formed by parasites of carnivores. One more Babesia sequence variant detected in an I. persulcatus tick from the Baikal region belonged to the cluster formed by parasites of cattle and wild cervids (B. divergens, Babesiacapreoli, B. venatorum, Babesiaodocoilei, etc.).

Human gut microbiota community structures in urban and rural populations in Russia

The microbial community of the human gut has a crucial role in sustaining host homeostasis. High-throughput DNA sequencing has delineated the structural and functional configurations of gut metagenomes in world populations. The microbiota of the Russian population is of particular interest to researchers, because Russia encompasses a uniquely wide range of environmental conditions and ethnogeographical cohorts. Here we conduct a shotgun metagenomic analysis of gut microbiota samples from 96 healthy Russian adult subjects, which reveals novel microbial community structures. The communities from several rural regions display similarities within each region and are dominated by the bacterial taxa associated with the healthy gut. Functional analysis shows that the metabolic pathways exhibiting differential abundance in the novel types are primarily associated with the trade-off between the Bacteroidetes and Firmicutes phyla. The specific signatures of the Russian gut microbiota are likely linked to the host diet, cultural habits and socioeconomic status.

[Clinical and ultrasound features of gallbladder pathology in patients with a weight deficit]

We undertook analysis of clinical and instrumental features of gallbladder pathology in patients with a weight deficit for the elucidation of peculiarities of eating behavior, blood leptin level, and cytokine content of gastric biopsies. Underweight patients with inflammatory and dysfunctional diseases of gallbladder more frequently than others presented with abdominal pain syndrome. All patients enrolled in the study showed every type of eating disorders with the predominance of the limiting behavior. Weight deficit in patients with chronic cholecystitis was associated with hyperleptinemia and increased production of proinflammatory cytokines.

[Field of view changes after vitreomacular surgery: a treatment quality criteria]

The study enrolled 177 patients that had been admitted to the Research Institute of Eye Diseases of the Russian Academy of Medical Sciences for diagnostics and treatment - 134 patients with idiopathic macular hole and 43 patients with epiretinal fibrosis. All vitreomacular surgeries were performed between 2005 and 2011. Visual field defects were seen in all groups and were classified as either peripheral or paracentral, or concentric. The groups differed by the rate and the localization of the visual field defects. A direct relation between the severity of iatrogenic retinal damage, the extent of postoperative retinal thinning and the presence/type of visual field defects was established. Causes and risk factors of visual field loss after vitreomacular surgery have been identified and analyzed. Preventive measures for this complication have been proposed. Treatment efficacy varied depending on the causes. Acute peripheral visual field loss--"tunnel phenomenon"--as a result of significant iatrogenic local retinal damage during vitreomacular surgery has been described.

[Vitrectomy effect on ocular hydrodynamics in proliferative diabetic retinopathy and nonvascular pathology]

The goal of the study was to determine vitrectomy effect on ocular hydrodynamics. Patients were divided into 2 groups: patients with diabetes mellitus (DM) were enrolled in the 1st group, indications for vitrectomy were vitreous hemorrhage or diabetic macula edema. The 2nd group included patients without DM, indications for vitrectomy were macula hole, epiretinal fibrosis. Electronic tonography was used to measure the main ocular hydrodynamic parameters before and 2-12 months after the surgery. Though intraocular pressure (IOP) increased after vitrectomy in all patients, the true IOP was normal in the majority of them (60%) and did not require medical correction. In the rest of cases IOP increase required medical treatment: in 23% during 1 month, in 11% during 6-12 months. In subsequent follow-up during 2 years no glaucoma signs were revealed.

[Analysis of factors causing peripheral visual field defects after vitreomacular surgery]

As a result of the study analysis of potential causes of visual field defects (VFD) after vitreomacular surgery is performed. 110 cases are enrolled in the study: 81 patient with macular hole and 29 patients with epiretinal fibrosis. Correspondence of VFD to position of irrigation port including unusual inferior-nasal position was revealed as well as VFD absence in epiretinal fibrosis operated without air pump. VFD did not appear after lowering of air pump pressure by 15-20 mmHg. The cause of VFD after vitreomacular surgery is a mechanical damage of internal retinal surface by directed air/gas jet after total fluid exchange with too high pressure in an air pump. This complication is an easily preventable iatrogenic effect and may serve as one of quality criterion for this treatment procedure.

[Genotypes 4 and 5 of the tick-borne encephalitis virus: features of the genome structure and possible scenario for its formation]

On the basis of the comparison of complete genome structures of 32 strains and gene E fragments (160 ndt) of 643 strains and RNA isolates of tick-borne encephalitis (TBE) virus, we confirmed our previously expressed assumption (Zlobin V.I. et al, 2001) of existence, along with the three major genotypes, of genotypes 4 (strain 178-79) and 5 (strain 886-84). "Mosaic" structure of the polyprotein in the two strains was established. It manifests itself in particular in the sequences of 14 positions (C-3, E-206, NS1-54, NS-285, NS2A-100, NS2A-127, NS2A-174, NS2A-175, NS2A-225, NS3-376, NS4B-28, NS4B-96, NS5-18, NS5-671) containing the amino acids strictly conserved for each of the three major genotypes and is consistent with a uniform pattern of distribution of nucleotide substitutions that are specific for genotypes 1, 2 and 3. Possible scenario of the origin of TBE genotypes 4 and 5 was suggested.

[Colonic pathology in patients with liver cirrhosis]

The study of 146 patents with liver cirrhosis of different classes using clinical, endoscopic, morphological and immunohistochemical methods revealed characteristic colonic changes. The destructive and atrophic changes in colonic mucosa were associated with increased morphometric parameters of serotonin- and chromogranin A-positive epithelyocytes. Capillary dilatation in colonic mucosa developed earlier than rectal varicose veins and may be an earlier sign of portal colonopathy.

[Anemia and gastroesophageal reflux disease in patients with coronary heart disease]

We studied the relationship between anemia and chronic diseases of the upper gastrointestinal tract in patients with CHD. Patients with CHD and gastroesophageal reflux disease (GERD) had the lowest hemoglobin levels and erythrocyte counts in the absence of pronounced independent effect of GERD. This finding suggests common pathogenesis of CHD, GERD and anemia in patients with coronary problems.

[Hepatic encephalopathy and colon pathology in liver cirrhosis]

to define a role of structural and functional changes of a colon, expression indicators of epithelial cells of mucous coat of colon that produce serotonin and hromogranin-A at in encephalopathy development at liver cirrhoses. We have examined 146 patients with liver cirrhosis of various classes using the clinical, endoscopic, morphologic and immunohistochemical methods. It is established that with increase of a class of a cirrhosis frequency of revealing of a hepatic encephalopathy, structural changes, degree dysbacteriosis of a colon. Progressing of a hepatic encephalopathy at liver cirrhoses associates with development destructive and atrophic changes of a mucous membrane of a colon and a dysbacteriosis. The increase in the morphometric rates of epithelial cells of mucous coat of colon that produce serotonin and hromogranin-A at liver cirrhoses plays a part in development of a manifesting of a hepatic encephalopathy.

[Optic neuropathies of different etiology and normal tension glaucoma: the point of differential diagnosis]

62 patients (109 eyes) with glaucoma-like optic nerve head cupping and normal IOP indices (Po not more than 21 mm Hg) were examined to find the etiology of optic nerve changes. Regarding corneal biomechanics new-onset primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) were diagnosed in 27% and 3% of examined patients respectively. In 59% of patients optic neuropathy (ON) of different etiology was found to be the cause of glaucoma-like optic nerve changes including compression ON due to lesion of intracranial portion of optic nerve and chiasma in 6% of cases. In 11% physiologic large optic nerve head cupping with normal visual functions and absence of nerve fiber structural changes was found.

[Detection of recombinations in tick-borne encephalitis virus by using computer analysis of viral genomes]

Computer programs were used to search for tick-borne encephalitis (TBE) virus recombinants among the isolates whose complete nucleotide sequences are deposited in the GenBank database. The application of RDP, Chimaera, Maximum chi2, and TOPAL programs has revealed recombinant sites in a number of sequences, which indicates that TBE virus has recombinations and that the programs are suitable for their detection.

[Diagnostic value of macular morphometry in patients with primary open-angle glaucoma]

In this article the results of practical use of central retinal zone (CRZ) tomography in primary open-angle glaucoma (POAG) measured with RTA (Retinal thickness Analyzer, Talia Technology Ltd., Israel) are presented. 460 patients (790 eyes) aged 45-85 years old were included into the study. Significant decrease of CRZ minimal thickness and perifoveal region thickness (p < 0.05 and p = 0.01 respectively) was revealed in patients with POAG compared with control group. Morphometric data showed correlation with decrease of light sensitivity and visual field defects detected with static perimetry. This fact confirms information value of central retinal morphometric changes for glaucoma diagnosis.

[Detection of Borrelia miyamotoi in ticks Ixodes persulcatus from Russia]

Unfed adult Ixodes persulcatus ticks from five regions of Russia were examined to analyze the distribution and diversity of Borrelia miyamotoi. DNA of B. miyamotoi was found in 1.8% of ticks from Leningrad Oblast, 2.9% from Sverdlovsk, 4.5% from Novosibirsk, 2.3% from Irkutsk Oblast, and 2.5% from Khabarovsk Krai. The molecular typing of the B. miyamotoi DNA was based on the partial sequencing of the 16S rRNA, p66, and glpQ genes. The only genetic variant of B. miyamotoi was detected in all samples of ticks collected from these five territories.

[Diagnosis of circulatory disorders in the optic nerve in primary open-angle glaucoma. Communication 1. The circulatory system in the orbital portion of the optic nerve and its anatomic and topographic features]

The review analyzes the implication of ischemia in the pathogenesis of primary open-angle glaucoma. It gives the opinions of leading Russian and foreign specialists who deal with this problem. The basic studies of the morphology of the optic nerve head and its circulatory system are assessed. The specific features of the structure of the orbital arterial system based on the types of ocular arterial branching via formation of intraocular circulation are compared.

[Diagnosis of circulatory disorders in the optic nerve in primary open-angle glaucoma. Communication 2. New technologies for the imaging and evaluation of the circulatory system in the optic nerve head]

The review details the basic principles of the optic nerve head circulation. It analyzes the diagnostic capacities of various study methods that are both traditional and proposed and tested in the past decade. The results of Russian and foreign specialists' studies based on Doppler ultrasound study of the ocular artery, short posterior ciliary arteries, and central retinal artery are given.

[The genetic variability and genotyping of tick-borne encephalitis virus with deoxyoligonucleotide probes]

A panel of genotype-specific molecular probes has been designed, which is used to indicate and differentiate tickborne encephalitis (TBE) virus. It assesses the individual genetic structure of each strain since the targets for the probes are the variable sequences of all 10 virus genes, which are specific for each of three genotypes. The molecular nucleic acid hybridization by means of the panel was used to study 273 TBE virus strains. Isolated from a Eurasian area; along with the representatives of three genotypes, the virus strains, the genomic structures of which do not fit in the established concept on three genotypes, circulate in Eastern Siberia.

[Clinical and morphological characteristics and some mechanisms of portal gastroduodenopathy in liver cirrhosis]

We have found out the clinical presentations and peculiarities of endoscopic and morphologic view of pathologies of mucous membrane of gastroduodenal zone caused by liver cirrhosis. We have examined 74 patients with liver cirrhosis of viral and nonviral etiology using the clinical, endoscopic, morphologic and immunohistochemical methods.We have found that during liver cirrhosis morphometric rates of epithelial cells of mucous coat of stomach that produce somatostatin and endothelin-1 decrease and morphometric rates of epithelial cells that produce nitrogen oxide synthase increase. We have also found out that during liver cirrhosis proliferate activity decrease and apoptosis of epithelial cell of mucous coat of stomach increase.

[Diagnostic criteria for different clinical variants of diverticular disease]

New diagnostic criteria for different variants of diverticular disease (DD) are considered based on the examination of 110 patients. Patients of group 1 (n = 77) showed no signs of diverticulitis in contrast to group 2 (n = 33). Two control groups comprised 38 patients with chronic hypomotor colitis and 25 practically healthy subjects respectively. Dynamic observations included clinical and endoscopic examination supplemented by morphological and immunohistochemical Studies. It was shown that DD developed in association with undifferentiated dysplasia of connective tissue, increased number of P substance-inducing colonocytes, and lowered density of vasointestinal peptide-reactive cells. Diagnostically significant criteria in patients with diverticulitis were grade II-III intestinal dysbiosis and increased number of mast cells in rectosigmoid nucosa.

[Clinical and morphological features of gastric and duodenal lesions in patients with chronic hepatitis]

Clinical presentation, endoscopic picture and morphological changes of gastric and duodenal mucosa were evaluated in 75 patients with chronic hepatitis of different (viral and non-viral) etiology. Endoscopic, morphological, and immunohistochemical studies revealed deterioration of morphometric characteristics of somatostatin-immunopositive epitheliocytes in gastric mucosa and their improvement in epitheliocytes producing endothelin-1 and nitric oxide synthase. These changes were associated with decreased proliferative activity and enhanced apoptosis of epitheliocytes in gastric mucosa.