Background. Changes in the human oral microbiota is an adaptive process. Infections will be particularly manifest in extreme conditions, especially during a long stay in space flight, where the astronaut is exposed to various nonspecific stresses. Aim the aim of the work is to estimate the complex influence of 14-day isolation conditions of human being in sealed environment on the state of natural barriers of periodontal colonization. Methods. During the experiment 6 volunteer subjects (4 men and 2 women) aged 24 to 45 years old were confined for 14 days to an air-tight space simulating a spaceship capsule. Then from 6 to 18 days after leaving the experiment the experimental group (4 people) received Lactobacillus spp. autoprobiotics once a day on an empty stomach in the morning. During this period the control group (2 persons) took Linex (Lebenin: Lactobacillus acidophilus (species L. gasseri) 300 mg, Bifidobacterium infantis 300 mg, Enterococcus faecium 300 mg, lactose 50 mg). Qualitative and quantitative changes of oral microbiota, concentration of immunoglobulins (sIgA, IgA, IgM) and cytokines (IL-6, IL-8, IL-1, IL-4, INF, TNF) in periodontal samples were recorded. The number of periodontopathogens and regional blood flow in the periodontium under conditions of prolonged confinement and hypokinesia were studied. Results. In comparison with the background period during the time of isolation, a quantitative growth of obligate periodontopathogens was observed in the subjects. This was accompanied by increased levels of immunoglobulins (IgM, IgA, sIgA) and pro-inflammatory cytokines (IL-1, IL-6, IL-8). There was an increase in blood flow in the arteriolo- venular part of the microcirculatory channel of periodontal tissues after leaving isolation. Subsequently, there was a tendency to optimize microbiocenosis through the use of probiotic and autoprobiotic agents. Along with this, there was a decrease of anti-inflammatory interleukin IL-4 practically to the initial values on the 18th day.

Introduction. For the treatment of patients with hypoxemic form of respiratory failure, thermal oxygen-helium mixture (OHM) therapy is used.The aim of the work is to study the effect of OHM on the state of the microcirculatory bed in viral pneumonia caused by COVID-19 in patients with aggravated and unaggravated anamnesis.Materials and methods. There were 8 patients with an uncomplicated anamnesis, 11 with AH1–2 degree, 11 with AH1–2 degree and type II diabetes. The parameters of blood flow in the MVB were recorded with an ultrasound dopplerograph. OHM therapy (O2 – 30 %, He – 70 %, t=+95 ºС): 5 min breathing, 5 min rest – 3 cycles.Results. Before the OHM therapy, the level of «basic perfusion» was increased in group 3: significantly high Vs (p=0.02) and Vd (p=0.006), low RI (p=0.015) relative to group 1, this indicates a reduced vascular tone and venous congestion. After the OHM session in patients of group 1, the speed of Vs and Vd increased, the indices RI and PI decreased. In group 2 – Vs, Vd and Vam increased, RI decreased. The effect is long lasting. In group 3, the effect was noted on day 5, short-term. Conclusions. OHM therapy has a positive effect.