Federal medical biological agency of Russia's efforts to support Russian athletes during COVID-19 outbreak.

This paper dwells upon COVID-19-related efforts of the Center for Sports Medicine, Federal Medical and Biological Agency of Russia. The Agency has the following precautions in place: regular polymerase chain reaction (PCR) testing of athletes and staff; double PCR testing before going to training camps or medical examinations; isolating athletes and their traceable contacts when COVID is suspected; observation and isolation wards set up at training camp venues. Athlete vaccination has begun. Athletes are provided online advice on health, diet, and exercising plus special care for chronically ill athletes and remote psychological counseling. Athletes recovering from COVID-19 are offered rehabilitation programs and doctor-supervised return to training. Specialists of the Research Department at FMBA's Center for Sports Medicine carried out a research dedicated to the prevalence of COVID-19 and different variants of its course in Russian athletes. The study period lasted from March to December 2020. A total of 27,438 records were analyzed. In May, June, July and August 2020, the percentage of positive PCR tests for athletes was significantly lower than the nationwide percentage at p < 0.05, Pearson's chi-squared test. However, the differences were nullified by September-October. The disease was mild or asymptomatic in most patients. Athletes of summer sports were found to be most likely to contract COVID-19.

[Acute retinal necrosis caused by varicella zoster virus]. / Ostryi nekroz setchatki, vyzvannyi virusom opoyasyvayushchego gerpesa.

Incidence of Herpes Zoster is relatively high. Herpes zoster ophthalmicus is one of the most common forms of the disease. Necrotising herpetic retinopathies (including acute retinal necrosis) are rare and usually these complications are presented in literature as individual cases. However, necrotising herpetic retinopathy can lead to complete loss of visual. The article reviews modern data on causation, diagnosis and treatment of acute retinal necrosis analyzing 40 open access articles from EBSCO published in 2011-2019, and describes the modern views on the prevalence and most important clinical features of herpetic acute retinal necrosis. Some contradictory opinions have been revealed concerning the diagnostic criteria and surgical treatment of acute retinal necrosis.

METALLOPROTEINS DURING DEVELOPMENT OF WALKER-256 CARCINOSARCOMA RESISTANT PHENOTYPE.

The study was focused on the detection of changes in serum and tumor metal-containing proteins in animals during development ofdoxorubicin-resistant phenotype in malignant cells after 12 courses of chemotherapy. We found that on every stage of resistance development there was a significant increase in content of ferritin and transferrin proteins (which take part in iron traffick and storage) in Walker-256 carc'inosarcoma tissue. We observed decreased serumferritin levels at the beginning stage of the resistance development and significant elevation of this protein levels in the cases withfully developed resistance phenotype. Transferrin content showed changes opposite to that offerritin. During the development of resistance phenotype the tumor tissue also exhibited increased 'free iron' concentration that putatively correlate with elevation of ROS generation and levels of MMP-2 and MMP-9 active forms. The tumor non-protein thiol content increases gradually as well. The serum of animals with early stages of resistance phenotype development showed high ceruloplasmin activity and its significant reduction after loss of tumor sensitivity to doxorubicin. Therefore, the development of resistance phenotype in Walker-256 carcinosarcoma is accompanied by both the deregulation of metal-containing proteins in serum and tumor tissue and by the changes in activity of antioxidant defense system. Thus, the results of this study allow us to determine the spectrum of metal-containing proteins that are involved in the development of resistant tumor phenotype and that may be targeted for methods for doxorubicin sensitivity correction therapy.