[Optical coherence tomography angiography in the diagnosis of myopic choroidal neovascularization]

Purpose - to perform a complex assessment of the retina and choroid in patients with pathological myopia (PM) complicated by subretinal neovascularization, and to determine the changes that govern the development of myopic subretinal neovascular membrane (SNM).

MATERIAL AND METHODS

The study examined 48 patients (40 females, 8 males) aged 18 to 54 years with pathological myopia complicated by SNM. All patients underwent standard ophthalmological examination including optical coherence tomography (OCT).

RESULTS

Myopic SNM was detected in 56 eyes of 48 examined PM patients (the process was bilateral in eight patients). A pronounced increase in the axial eye length was accompanied by extreme thinning of the choroid, dystrophic changes in the posterior pole, and decreased visual acuity. In 20% of cases (11 eyes), the disease was detected during its active phase, in 37.5% (21 eyes) - scarring stage, in 43% (27 eyes) - atrophy stage. The blood flow inside the membranes was recordable at all stages of the pathological process. Perforating intrascleral vessels that communicate with neovascular membranes could be seen in all patients. The filling-up of these vessels with contrast in the early arterial phase of fluorescein angiography (FA) suggests that they are the branches of the short posterior ciliary arteries (SPCA).

CONCLUSION

The key link in the pathogenesis of myopic SNM is pathological arteriogenesis, in which the branches of the SPCA are the source of the formation of neovascular membranes.

[Visualization of retinal blood flow disturbances in acute retinal ischemia syndrome]

Vascular disorders account for a significant proportion of acute loss of vision. In recent years, scientific and technical progress in ophthalmology has provided new opportunities in the study of vascular pathology, significantly expanding the understanding of their pathogenesis. The article presents a clinical case of a patient with acute retinal ischemia syndrome who had retinal blood flow disturbances studied using optical coherence tomography (OCT) imaging. It demonstrates extensive possibilities of diagnostics of ischemic retinal lesions using OCT angiography that make this method the most informative in terms of evaluating the blood flow at different levels, independently in each vascular plexus.

[Complex assessment of retinal ischemic damage in patients with retinal vein occlusion]

PURPOSE

To evaluate the effectiveness of treatment and the possibility of restoring visual functions in patients with retinal vein occlusion (RVO) depending on the initial degree of macular ischemia.

MATERIAL AND METHODS

The study included 84 patients with RVO. The main inclusion criteria were the presence of macular edema in the setting of RVO with the duration of no more than 3 months and without any previous treatment. All patients underwent intravitreal injections of an angiogenesis inhibitor, followed by laser treatment when necessary. A comparative analysis of the results was carried out in groups that were opposite in terms of the clinical effect - before the start of the therapy, after 1 month, and after 12 months. All patients and the control group members underwent standard ophthalmological examination as well as electroretinography, fluorescence angiography, optical coherence tomography (OCT), and OCT angiography.

RESULTS

Based on data obtained during 12 months of the follow-up, the comparative analysis of the initial ophthalmic status of patients with RVO with opposite clinical effect resulted in derivation of 3 clinical groups that correspond to the degrees of macular ischemia - mild, moderate and severe.

CONCLUSION

Determination of the degree of macular ischemia at the stage of primary diagnosis can improve the treatment effectiveness and inform the patients about the sequence and duration of anti-VEGF therapy. Intravitreal injections of ranibizumab in retinal vein occlusion are carried out before the elimination of macular edema and further in the on-demand mode, while the number of injections can vary from one to monthly injections during the year.

[Immunogenic and protective characteristics of surface antigens 6 and d of Burkholderia pseudomallei]

AIM

Extraction of complex of Burkholderia pseudomallei antigens 6+d (Ag6+d) and study of its immunogenic and protective characteristics.

MATERIALS AND METHODS

Studied antigens were obtained from acrtone-dried cells of B. pseudomallei 57576. Experiments were performed on white mouse model. Microbiological, immunochemical as well as immunological methods were used in the study.

RESULTS

It was shown that antigenic complex 6+d has a glycoprotein nature and corresponds to high-polymeric catode-moving antigen 6 with molecular mass 500 kDa and anode-moving antigen d with molecular mass 40 - 55 kDa. Immunogenic and protective characteristics of surface antigenic complex 6+d was studied. It was noted that Ag6+d caused reliable stimulating effect on cellular arm of immune system of white mice appeared in activation of delayed-type hypersensitivity reactions, enhanced phagocytic activity of polymorphonuclear macrophages as well as increased expression of Fc-receptors on macrophages and neutrophils.

CONCLUSION

Observed stimulation of cellular immunity by surface antigens was confirmed during study of their protective characteristics on the model of experimental meloidosis in white mice.

[Molecular genetic analysis of Pseudomonas aeruginosa strains isolated from environment and patients in health care facilities]

AIM

Analysis of genetic heterogeneity of Pseudomonas aeruginosa strains isolated in and out of hospitals.

MATERIALS AND METHODS

To study the genetic diversity of 36 strains of P. aeruginosa plasmid analysis, random amplified polymorphic DNA (RAPD) technique as well as polymerase chain reaction for detection of virulence genes algD, lasB, toxA, plcH, plcN, exoS, nan1, and nan2.

RESULTS

Epidemically important strains were found in different ecological niches. It was shown that these virulence factors could play important roles in pathogenesis of infection.

CONCLUSION

RAPD technique was effective for analysis of P. aeruginosa isolates. Number of studied typing bands differed between related isolates for each random primer.

[Phagocytosis of Burkholderia mallei as a criterion for immunogenicity evaluation of its capsular antigens]

Test-system using index of phagocytosis of noncapsulated mutant loaded by one of the several capsular antigenic complexes was developed and used for screening for both immunogenic and protective capsular antigens of B. mallei. Direct correlation between index of phagocytosis, level of delayed-type hypersensivity, and protective effect of capsular antigens has been shown on the model of experimental melioidosis in susceptible white mice, guinea pigs and white rats. Obtained results let to use the developed test-system for initial selection of B. mallei protective capsular antigens and their further study as potential components of preparations for specific prophylaxis of glanders and melioidosis.

[Immunogenicity of surface and capsular antigens of Burkholderia]

Study showed that five (C3, C6, C9, C10, C11) out of ten chromatographic fractions of surface and capsular antigens of B. mallei significantly stimulated cell-mediated immunity that manifested in activation of delayed hypersensivity reactions (DHS) and phagocyteability of noncapsulated avirulent strain of B. mallei with added surface and capsular antigenic complexes. Other fractions did not stimulate cell-mediated immunity, furthermore, fraction C8, which contained capsular biopolymer with mass of 200 kD (Ar8), was characterized by immunosuppressive effect on DHS and phagocytosis. Observed stimulation of cell-mediated immunity by fractions referred above has been confirmed by assessment of their protective effects on the model of experimental melioidosis in white rats. Relationship between markers of humoral and cell-mediated immunity, including markers of specific response, was not observed.

[Classification signs of end-stage pigmented retinitis]

Identification of objective criteria for early-stage pigmented retinitis (PR) remains urgent today. Visual system changes reflecting retinal metabolic and structural disturbances (a change in the time and amplitude parameters of ERG, an increase in dark adaptation, changes in the color palette and the thickness of layers of photoreceptors and pigment epithelium of the retina on the OST scans) were detected in 31% of the examined relatives of patients with PR. The authors show the diagnostic value of retinal optic coherent tomography in the diagnosis of PR and the expediency of its use for objective estimation of retinal structural changes along with functional studies. The statistical studies including descriptive, regression, and discriminant analyses have provided evidence that the characteristics of the visual system in patients with end-stage PR differ from those in the controls. Studies that can determine differences in the state of the visual system of the groups under study and significantly discriminate persons with the normally functioning visual system from patients with PR have been identified.

[Use of infusoria Paramecium caudatum for the evaluation of the toxicity of antigens of different causative quarantine agents]

The results of the evaluation of the toxicity of bacterial antigens obtained from the causative agents of plaque, glanders, melioidosis, cholera on infusoria of the species P. caudatum, as well as on cell lines L-929, CHO K-1 and peritoneal macrophages of BALB/c mice, are presented. As revealed in this study, the method of toxicity determination on infusoria is similar in its sensitivity to the methods of testing on. CHO K-1 and L-929 cells, but the former is simpler, more available and permits the determination of toxic doses producing disturbances in the vital activity of the infusoria, but not leading to their death.

[Immune response in experimental animals immunized with Burkholderia pseudomallei surface antigens]

The influence of the chromatographic fractions of B. pseudomallei surface antigenic complex (C, C1, D, H) on immune response in white rats and white mice was under study. These antigenic complexes were noted to produce perceptible stimulating effect on the immune system of white rats, in contrast to that of white mice. The immunization of the mice the above-mentioned fractions suppressed the phagocytic activity of peritoneal macrophages (PM) and slightly enhanced cell-mediated immunity. In experiments on white rats, fraction C induced the growth of specific antibody titers and stimulated the phagocytic activity of PM, as well as the indices of delayed hypersensitivity (DH). Fraction D showed a lower level of the induction of the phagocytic activity of PM and was inactive in the manifestation of cell-mediated immunity, but induced a high level of humoral immunity. Antigenic complexes C1 and H increased the phagocytic activity of PM and DH characteristics with a low level of antibody production. The studied fractions of the causative agent of melioidosis decreased the content of bactericidal cationic proteins (BCP) in rat blood neutrophils, and in mice a decreased content of BCP in phagocytes was registered. The fractions increased the activity of myeloperoxidase in blood neutrophils in mice and rats. As revealed with the use of immunoelectrophoresis, SDS PAAG electrophoresis and immunoblotting, the surface antigenic complex contained proteins of 18, 22, 39 kD and glycoproteins 42, 55, 90 kD. The latter glycoprotein was found in all the fractions under study, having protective properties.

[Immunotropic and immunogenic properties of Burkholderia pseudomallei surface and membrane antigens]

The immunotropic and immunogenic properties of some chromatographic fractions of B. pseudomallei surface antigenic complex, as well as the preparations of B. pseudomallei outer and cytoplasmic membranes, were studied. The difference between the biopolymers under study in cytotoxicity, humoral and cell-mediated immunity characteristics, phagocytic activity were established. Some antigenic fractions (B, C, C1, H) showed perceptible protective activity (25-60%) in experiments on mice infected with B. pseudomallei virulent strain. One of the preparations of cytoplasmic membrane (CM-1) was also found to have protective properties (30%). Complex immunization with the antigenic complexes under study, introduced in combination with the immunomodulating agent Bromantan, was shown to enhance the protective effect.