[The role of lipid metabolism and antioxidant system changes in the development of retinal vein occlusion].

PURPOSE: To compare changes in lipid metabolism and antioxidant status in patients with retinal vein occlusion (RVO) with that in patients with a history of ischemic stroke and in patients with no clinical manifestations of atherosclerosis. MATERIAL AND METHODS: A total of 111 patients were enrolled in the study. Group 1 included 80 patients with RVO and grade 2-3 stage II-III essential hypertension, group 2-11 patients with grade 3 stage III essential hypertension, high cardiovascular risk and a history of ischemic stroke. The control group included 20 patients with no clinical manifestations of atherosclerosis. All patients underwent a standard ophthalmic examination, fluorescent retinal angiography, lipid metabolism and redox system assessment. RESULTS: The levels of low-density lipoproteins (LDL) and cholinesterase were higher in study groups than in controls regardless the type of RVO. A statistically proven increase in oxidized LDL (oxLDL) was found in patients with complicated hypertension and ischemic RVO. A direct correlation was determined between the level of anti-oxLDL IgG and lipid peroxidation activity (LP) (R = 0.376; p = 0.136) as well as the levels of glutathione peroxidase (GPx) (R = 0.529; p = 0.029) and GPx per gram of hemoglobin (R = 0.543; p = 0.024) in patients with branch RVO. Redox system assessment showed a decrease of thiols and an increase of LP metabolites. CONCLUSION: The results demonstrated that retinal vein occlusions develop under disorders of lipid metabolism similar to those in patients with a history of ischemic stroke. The correlation between the level of anti-oxLDL IgG and LP points to the redox system involvement in the intricate pathogenesis of RVO.

[Pathogenesis of retinal vein occlusions].

Retinal vein occlusion (RVO) is a multifactorial disease and its pathogenesis is still not fully understood. Mechanical, hemodynamic, rheological, coagulation, biochemical, and immunological factors are involved. Two currently prevalent theories of RVO pathogenesis are the mechanical theory and the "coagulopathic" theory. The latter implies an imbalance between thrombogenic factors and antithrombogenic protection. According to some authors, endothelial dysfunction plays a large part in thrombosis development, neoangiogenesis, vascular remodeling, intravascular activation of platelets and leucocytes. In recent studies increasing emphasis is being placed on investigation of immune-mediated mechanisms of vein occlusions. RVO can also be associated with combined hypoxic and free radical tissue damage.

[Contemporary pharmacogenetic approaches to the treatment of age-related macular degeneration].

A study on the role of CFH, HTRA and IL-8 gene polymorphism in age-related macular degeneration (AMD) development has been conducted. At the first stage of the study genetic testing was done in 69 patients with exudative AMD and 370 random Moscow citizens without the disease. The goal of the second stage was to determine the influence of gene polymorphism on patient's response to endovitreal ranibizumab treatment. For that, visual acuity and foveal thickness were assessed before and after ranibizumab injections in 120 patients with wet AMD. All patients were genotyped for the genes of interest. The results showed that the presence of homozygous 402H polymorphism in CFH gene, as well as homozygous (-625)A mutation in HTRA1 gene, determines certain clinical presentations. Moreover, visual acuity below 0.1 and presence of 402H, (-625)A and (-251)A alleles in both copies of all three genes (CFH, HTRA and IL-8) are negative predictors of disease severity and antiangiogenic treatment response.

New approaches for isolation of previously uncultivated oral bacteria.

A significant number of microorganisms from the human oral cavity remain uncultivated. This is a major impediment to the study of human health since some of the uncultivated species may be involved in a variety of systemic diseases. We used a range of innovations previously developed to cultivate microorganisms from the human oral cavity, focusing on anaerobic species. These innovations include (i) in vivo cultivation to specifically enrich for species actively growing in the oral cavity (the "minitrap" method), (ii) single-cell long-term cultivation to minimize the effect of fast-growing microorganisms, and (iii) modifications of conventional enrichment techniques, using media that did not contain sugar, including glucose. To enable cultivation of obligate anaerobes, we maintained strict anaerobic conditions in most of our cultivation experiments. We report that, on a per cell basis, the most successful recovery was achieved using minitrap enrichment (11%), followed by single-cell cultivation (3%) and conventional plating (1%). Taxonomically, the richest collection was obtained using the single-cell cultivation method, followed by minitrap and conventional enrichment, comprising representatives of 13, 9, and 4 genera, respectively. Interestingly, no single species was isolated by all three methods, indicating method complementarity. An important result is the isolation and maintenance in pure culture of 10 strains previously only known by their molecular signatures, as well as representatives of what are likely to be three new microbial genera. We conclude that the ensemble of new methods we introduced will likely help close the gap between cultivated and uncultivated species from the human oral cavity.

[The role of systemic disorders in diabetic macula edema and main approaches for their correction].

The review of Russian and international literature devoted to up-to-date opinion about the role of systemic disorders in diabetic macula edema is represented. The main approaches for the correction of these conditions are characterized. Special emphasis is put on plasmapheresis as a treatment option for hemocorrection, its mechanism of action and indications for use.

[Visual fixation features after treatment of exudative age macular degeneration].

Changes of visual fixation in patients with choroidal neovascularitation (CNV) associated with age macular degeneration (AMD) after bevacizumab are studied. 45 patients (45 eyes) with active CNV treated with intravitreal bevacizumab were enrolled into the study. Visual fixation was studied before and 3-6 months after treatment using original method that included fundus foto and fluorescein angiography. Fixation relative to fovea and lesion was evaluated. Foveal fixation beyond lesion was found in 9%, foveal fixation within lesion--in 47%, extrafoveal fixation beyond lesion--in 18%, extrafoveal fixation within lesion--in 26% of patients. Changes of fixation localization after treatment was found in 24% patients. Examination of visual fixation may be useful for prognosis of anti-VEGF treatment efficacy in patients with CNV.

Cellulose- and xylan-degrading thermophilic anaerobic bacteria from biocompost.

Nine thermophilic cellulolytic clostridial isolates and four other noncellulolytic bacterial isolates were isolated from self-heated biocompost via preliminary enrichment culture on microcrystalline cellulose. All cellulolytic isolates grew vigorously on cellulose, with the formation of either ethanol and acetate or acetate and formate as principal fermentation products as well as lactate and glycerol as minor products. In addition, two out of nine cellulolytic strains were able to utilize xylan and pretreated wood with roughly the same efficiency as for cellulose. The major products of xylan fermentation were acetate and formate, with minor contributions of lactate and ethanol. Phylogenetic analyses of 16S rRNA and glycosyl hydrolase family 48 (GH48) gene sequences revealed that two xylan-utilizing isolates were related to a Clostridium clariflavum strain and represent a distinct novel branch within the GH48 family. Both isolates possessed high cellulase and xylanase activity induced independently by either cellulose or xylan. Enzymatic activity decayed after growth cessation, with more-rapid disappearance of cellulase activity than of xylanase activity. A mixture of xylan and cellulose was utilized simultaneously, with a significant synergistic effect observed as a reduction of lag phase in cellulose degradation.

Biodegradation kinetics of the nitramine explosive CL-20 in soil and microbial cultures.

The cyclic nitramine explosive CL-20 (C(6)H(6)N(12)O(12), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12 -hexaazaisowurtzitane) is a relatively new energetic compound which could be a persistent organic pollutant. To follow its biodegradation dynamics, CL-20 was added to soil alone or together with organic co-substrates and N-source and incubated under oxic and anoxic conditions. Without co-substrates, the CL-20 degradation was detectable only under anoxic conditions. The highest degradation rate was found under aerobic conditions and with the addition of co-substrates, succinate and pyruvate being more efficient than acetate, glucose, starch or yeast extract. When added to intact soil, CL-20 degradation was not affected by the N content, but in soil serially diluted with N-free succinate-mineral medium, the process became N-limited. About 40% of randomly selected bacterial colonies grown on succinate agar medium were able to decompose CL-20. Based on 16S rDNA gene sequence and cell morphology, they were affiliated to Pseudomonas, Rhodococcus, Ochrobactrum, Mycobacterium and Ralstonia. In the pure culture of Pseudomonas sp. MS-P grown on the succinate-mineral N(+) medium, the degradation kinetics were first order with the same apparent kinetic constant throughout growth and decline phases of the batch culture. The observed kinetics agreed with the model that supposes co-metabolic transformation of CL-20 uncoupled from cell growth, which can be carried out by several constitutive cellular enzymes with wide substrate specificity.