Andrey A. Zharov

Purpose of the study: to determine possibilities of ultrasound examination (US), ultrasound biomicroscopy (UBM), optical coherence tomography (OCT) and OCT-angiography (OCTA) in epibulbar lesions evaluation. Materials and methods. 64 patients (66 eyes) aged 41.5 ± 23.0 years with epibulabar lesions of various genesis were included in the study. In all cases US with scaling function and Colour Doppler (CD), UBM and OCT were performed. For qualitative and quantitative evaluation of tumors’ vascularity OCTA was performed with perfusion density (PD) registration. Results. The use of UBM made possible measurement of tumor thickness in 100.0 % of the cases and measurement of tumor base diameter in 95.6 %. OCT proved to be superior when compared with UBM in evaluation of tumors’ structure and state of conjunctival epithelium. OCT was not informative in assessment of highly pigmented lesions. US with CD allowed evaluation of epibulbar lesions with thickness over 1.4 mm and with base diameter over 3.6 mm. OCTA allowed visualization of tortuous vessels with uneven caliber and distorted course as well as an increase in PD. Signs indicative of malignancy were: maximum PD 50 % or more, 7 or more zones of “lace-like pattern” or at least one zone of “confluent pattern”. Conclusion. UMB is the most informative method in assessment of biometric parameters of epibulbar lesions. OCTA allows evaluation of quantitative and qualitative characteristics of tumors’ vessels.

There is a clinical case of mucogenic iris cyst with ocular hypertension. The patient had noticed an iris spot since childhood. At the age of 33, she was diagnosed with iridocorneal syndrome and iris cyst. At the age of 38, an IOP decompensation was the reason for fistulizing surgery. At 41 years, progression of the iris cyst was noted, which was an indication for iridectomy with iridoplasty. According to the histological examination, the cyst wall is presented by sclerotic iris stroma, as well as dense unformed fibrous tissue fused with Descemet's membrane. In the lumen of the cyst, mucous contents are determined with the formation of mucous globules and an admixture of native and hemolyzed erythrocytes, clusters of macrophages with abundant light vacuolated cytoplasm. The inner surface of the cyst is lined with mature multi-row cylindrical intestinal-type epithelium and numerous goblet cells.

We present a clinical case of untimely recognized and inadequately treated iris melanoma, which led to the development of secondary hypertension and secondary cataract in the absence of extrabulbar growth and the presence of bleb ossification during 6 months after trabeculectomy against the background of uveal melanoma. Ossification was not accompanied by an inflammatory reaction and allowed the surgically created a well function filtering bleb. The case confirms the need for a full examination of patients and for increasing the specialists level of oncological alertness.

Background and Aim: The pathogenesis of staphylococcal infections is mediated by virulence factors, such as enzymes, toxins, and biofilms, which increase the resistance of microorganisms to host immune system evasion. Testing and searching for standardized multi-level algorithms for the indication and differentiation of biofilms at the early stages of diagnosis will contribute to the development of preventive measures to control the critical points of technology and manage dangerous risk factors for the spread of infectious diseases. This research aimed to study the main stages of Staphylococcus aureus biofilm formation in in vitro experiments and to analyze the dynamics of respiratory syndrome development in chickens infected with these bacteria. Materials and Methods: Experimental reproduction of the infectious process was performed using laboratory models: 10-day-old White Leghorn chickens (n = 20). Before the experiments, the birds were divided into two groups according to the principle of analogs: Group I (control, n = 10): the birds were intranasally inoculated with 0.5 cm3 of 0.9% NaCl solution; Group II (experiment, n = 10): the birds were intranasally inoculated with a suspension of S. aureus bacteria, 0.5 cm3, concentration 1 billion/cm3. Results: Colonization of individual areas of the substrate under study in vitro occurred gradually from the sedimentation and adhesion of single motile planktonic cells to the attachment stage of microcolony development. Staining preparations with gentian violet due to the “metachromosia” property of this dye are a quick and fairly simple way to differentiate cells and the intercellular matrix of biofilms. Fixation with vapors of glutaraldehyde and osmium tetroxide preserves the natural architecture of biofilms under optical and scanning electron microscopy. Pure cultures of S. aureus microorganisms were isolated from the blood, lungs, small intestine, liver, kidneys, and spleen after 5–10 days during experimental infection of chickens. Clinical signs of respiratory syndrome developed within 5–6 days after infection. Acute and subacute serousfibrinous airsacculitis, characterized by edema and thickening of the membranes of the air sacs and the presence of turbid, watery, foamy contents in the cavity, was the most characteristic pathomorphological sign. The signs of acute congestive hyperemia and one-sided serous-fibrinous pneumonia developed with significant thickening of fibrinous deposits. In Garder’s gland, there was an increase in the number of secretory sections, indicating hypersecretion of the glands. In the lymphoid follicles of Meckel’s diverticulum, leukocytes, usually lymphocytes, and pseudoeosinophils were detected. Conclusion: Hydration and heteromorphism of the internal environment of biofilms determine the localization of differentiated cells in a three-dimensional matrix for protection against adverse factors. The most characteristic pathomorphological sign was the development of acute and subacute serous-fibrinous airsacculitis when reproducing the infectious process in susceptible models. There was a significant thickening of fibrinous deposits and signs of acute congestive hyperemia and one or two serous-fibrinous pneumonia developed. Keywords: airsacculitis, avian, biofilm, pathogenesis, respiratory syndrome pneumonia, Staphylococcus aureus.

Urinary tract infections occupy a special niche among diseases of infectious etiology. Many microorganisms associated with urinary tract infections, such as Klebsiella oxytoca, Enterococcus spp., Morganella morganii, Moraxella catarrhalis, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, Staphylococcus spp., and Candida spp., can form biofilms. The aim of this research was to study the effect of the enzyme L-lysine-Alpha-oxidase (LO) produced by the fungus Trichoderma harzianum Rifai on the biofilm formation process of microorganisms associated with urinary tract infections. Homogeneous LO showed a more pronounced effect than the culture liquid concentrate (cCL). When adding samples at the beginning of incubation, the maximum inhibition was observed in relation to Enterococcus faecalis 5960—cCL 86%, LO 95%; Enterococcus avium 1669—cCL 85%, LO 94%; Enterococcus cloacae 6392—cCL 83%, LO—98%; and Pseudomonas aeruginosa 3057—cCL 70%, LO—82%. The minimum inhibition was found in Candida spp. Scanning electron microscopy was carried out, and numerous morphological and structural changes were observed in the cells after culturing the bacterial cultures in a medium supplemented with homogeneous LO. For example, abnormal division was detected, manifesting as the appearance of joints in places where the bacteria diverge. Based on the results of this work, we can draw conclusions about the possibility of inhibiting microbial biofilm formation with the use of LO; especially significant inhibition was achieved when the enzyme was added at the beginning of incubation. Thus, LO can be a promising drug candidate for the treatment or prevention of infections associated with biofilm formation.

Purpose: to assess the potentials of optical coherence tomography-angiography (OCTA) in the evaluation of anterior segment (AS) uveal vessels in normal and pathological conditions.Material and methods. 20 healthy volunteers (40 eyes) with no ophthalmic pathology (the control group) and 85 previously untreated patients (85 eyes) with suspected tumors of the irido-ciliary area (the iris, the ciliary body and the peripheral sections of the choroid) were examined. All participants had optical coherence tomography (OCT) and OCTA of AS, with the qualitative assessment of scans (vessels pattern, lumen, tortuosity) and the quantitative assessment (vessel density index, VD%, for the affected zone). In ciliary body or choroid pathologies, VD index was measured for the conjunctiva in the focus projection. VD index included mean and local VD, as well as VD of perifocal tissues. In addition, B-mode ultrasound scanning and ultrasound biomicroscopy were performed.Results. OCTA scans in 4 sectors of the normal iris showed a predominantly radial pattern of conjunctival vessels positioning, with their lumen remaining the same along their entire visible length. The lowest VD value (38.5%) was registered in the temporal iris segment, while the highest (43.9%) was revealed in the inferior quadrant. In the iris tumors area, intrinsic vascularity molded in various vascular patterns was observed. Melanomas could be suspected because of the vessels oriented along the axis of the tumor and by non-uniform lumen of the vessels.Conclusion. AS-OCTA is an informative method for the visualization of iris vessels in normal conditions and in iris pathology and may be considered a valuable addition to the standard visualization techniques.

BACKGROUND: Optical coherence tomography angiography (OCTA) is a noninvasive method of eye microcirculation evaluation. Few reports are published on the use of OCTA for anterior segment (AS) vessels analysis in healthy eyes and in conjunctival tumors, and their vascular characteristics are still not thoroughly investigated. These questions are of importance, as it is known that tumors vasculature is indicative of the patients vital prognosis. AIM: The aim of our study was to investigate the potential of AS-OCTA in evaluation of normal conjunctival vessels architecture as well as that in melanocytic neoplasms. MATERIALS AND METHODS: 20 healthy volunteers (20 eyes) and 20 patients (20 eyes) with conjunctival nevi and melanomas were examined. AS optical coherence tomography (OCT) and AS-OCTA were performed. Scan analysis included qualitative assessment (vessels pattern, lumen, tortuosity) and quantitative assessment [perfusion density (PD, %) index]. Mean (MPD), maximum (MaxPD) and perifocal PD (PPD) were determined. RESULTS: In normal group, predominantly radial pattern of the vessels was revealed, their caliber remaining the same along their entire length; larger vessels were more often discovered in deep conjunctival layers. The lowest PD value (29.9%) was registered in the inferior conjunctival segment, and the highest (36.7%) in the nasal one. In the conjunctival tumors area tortuosity of the vessels, uneven vessels caliber along their length, and increase in the PD value were observed. Melanomas were characterized by an increase in the lace-like pattern and by presence of confluent pattern zones; MaxPD value was more than 50%. Significant difference was found between MPD values of normal conjunctiva and MPD values in conjunctival melanoma. CONCLUSIONS: AS-OCTA is an informative method for the visualization of vessels in normal conjunctiva and in conjunctival tumors. If the tumors vessels are unevenly distributed, MaxPD should be measured.

Introduction. Studies aimed at a direct research of human herpes viruses (HHVs) in the tumor material and eye media have not been carried out so far. Research goal to establish the frequency of detection HHVs DNA in the biomaterial of the eye and blood and to assess the specific humoral immunity to the causative agents of herpes virus infections in patients with uveal melanoma. Materials and methods. 38 patients with the uveal tract tumor were examined for the presence of DNA of HHV types 1 and 2 (HSV-1, 2), Cytomegalovirus (CMV), Varicella Zoster virus (VZV), EpsteinBarr virus (EBV) and herpes viruses 6 and 8 types (HHV-6, HHV-8) in tumor tissue, vitreous body, aqueous humour and blood plasma by real-time polymerase chain reaction; blood serum was studied by enzyme-linked immunosorbent assay (ELISA) for IgG and IgM antibodies to HHVs. Results. EBV DNA was present in tumor tissue in 20.6% of cases, in vitreous body in 4.2%, in blood plasma in 2.7%, and was not found in aqueous humor. Ig G antibodies to HSV-1, 2 and CMV were detected in 97.3% of cases, VZV 94.6%, HHV-6 32.4%, antibodies to HHV-8 were not detected. 20 patients (55.6%) had reactivation of chronic HSV-1, 2 infection, and 14 (38.9%) patients had reactivation of CMV infection. Markers of chronic EBV infection were found in all patients, its atypical reactivation was observed in 2 cases (5.4%). Conclusion. Our findings suggest the possible participation of EBV in the oncogenesis of the uveal tract and emphasize the need for further in-depth study of this problem.

Recent studies have shown that the gut microbiota plays an important role in the pathogenesis of gastrointestinal diseases in various animal species. There are only limited data on the microbiome in cats with varying grades of dysbiosis. The purpose of the study was a detailed analysis of the quantitative and qualitative fecal microbiota spectrum in cats with intestinal dysbiosis of varying severity. The data obtained indicate that, depending on the dysbiosis severity in cats, the intestinal microbiome landscape changes significantly. It has been established that, depending on the dysbiosis severity, there is a shift in the balance between the Gram-positive and Gram-negative bacterial pools and in the nature of the isolation of specific bacteria forms, in the amount of obligate microbiota isolation, as well as individual facultative strains. When analyzing the serotyping of E. coli cultures isolated at various grades of intestinal dysbiosis severity, differences were found both in the isolation amount of various serotypes from one animal and in the prevalence of certain serotypes for each disease severity. A retrospective analysis of the fecal microbiota sensitivity in cats with dysbiosis to antibacterial drugs showed that, depending on the disease severity, the number of isolates sensitive to antibiotics increases significantly.

ЦЕЛЬ ИССЛЕДОВАНИЯ Изучение возможностей оптической когерентной томографии в ангиорежиме (ОКТ-А) в оценке сосудов конъюнктивы в норме и при различных патологических состояниях. МАТЕРИАЛ И МЕТОДЫ Обследовано 17 здоровых добровольцев (34 глаза) без офтальмопатологии (группа контроля) и 62 пациента (68 глаз) с патологическими изменениями конъюнктивы. Им проводили оптическую когерентную томографию (ОКТ) и ОКТ-А переднего отдела глаза (ПОГ) с качественной оценкой (ход и калибр сосудов, наличие их патологической извитости) и количественным анализом ангиограмм с определением показателя сосудистой плотности — vessel density (VD,%) в зоне поражения конъюнктивы. Определяли среднюю (MVD) и локальную (LVD) VD, а также VD перифокальных тканей (PVD). РЕЗУЛЬТАТЫ Исследование ангиоархитектоники конъюнктивы в норме по восьми квадрантам показало преимущественно радиальную ориентацию конъюнктивальных сосудов, имеющих одинаковый калибр на всем протяжении. В большинстве случаев более крупные сосуды выявлялись в глубоких слоях конъюнктивы. Минимальное значение VD регистрировали в верхненаружном квадранте (33,3%), а максимальное — во внутреннем (38,9%). В зоне патологических процессов конъюнктивы, за исключением врожденных пороков развития, пингвекул и конъюнктивальной меланоцитарной эпителиальной неоплазии, наблюдались извитость сосудов с нарушением их хода, неравномерный калибр на протяжении сосуда и увеличение сосудистой плотности. О злокачественном характере новообразования свидетельствовало плотное распределение сосудов в опухоли при затруднении визуализации межсосудистых пространств, что подтверждалось данными патогистологического исследования. Меланомы характеризовались увеличением числа зон «кружевного паттерна», в участках максимального скопления новообразованных сосудов средний показатель LVD составил более 50%. ЗАКЛЮЧЕНИЕ Метод ОКТ-А ПОГ является информативным для визуализации сосудов конъюнктивы в норме и при патологии. При неравномерном распределении сосудов в зоне новообразования следует определять локальную сосудистую плотность.