COMPLEX RADIATION AND HYGIENIC MONITORING OF POPULATION ON RADIOLOGICALLY CONTAMINATED TERRITORIES OF ZHYTOMYR OBLAST IN 2021. / KOMPLEKSNYI RADIATsIINO-GIGIIeNIChNYI MONITORYNG MEShKANTsIV RADIOAKTYVNO ZABRUDNENYKh TERYTORII ZhYTOMYRS'KOÏ OBLASTI U 2021 ROTsI.

OBJECTIVE: the key factors identification in radiation dose formation in population of radiologically contaminatedareas of Zhytomyr oblast in the current period of accident through complex radiation and hygienic monitoring in reference settlements in 2021. MATERIALS AND METHODS: For complex radiationhygienic monitoring in Zhytomyr oblast, 10 settlements were chosen - Narodychi, Selets, Bazar, Rudnya Bazarska, Khrystynivka - zone 2, Motiyki, Zalissya, Davydky, Radcha, Nova Radcha - zone 3 of Narodychi district, in which the highest radiation doses were recorded after the accident at the Chornobyl Nuclear Power Plant. The research was carried out in June 2021. In order to determine the doses of internal radiation, 645 measurements were performed on whole body counters (WBC) (478 adults and 167 children). The 44 samples of milk, 45 samples of potatoes and vegetables, and 38 samples of wild products were collected in local farms and measured for the 137Cs and 90Sr content. Residents of the studied settlements (n = 220, 175 adults, and 45 children) were interviewed about the levels of consumption of staple foodstuffs. External radiation doses were evaluated in all the studied settlements. Mathematical, dosimetry, and radiochemical methods were applied. RESULTS AND CONCLUSIONS: Annual effective radiation doses of Zhytomyr oblast population in 2021 were formedmainly due to internal radiation ones that not exceeded 1.8 mSv * year-1 in adults and 0.5 mSv * year-1 in children against the radiologically contaminated territories (RCT) criterion of 1 mSv * year-1. Intake of 137Cs with milk and wild mushrooms, which traditionally occupy a significant part of diet in Zhytomyr oblast area and have consistently high levels of radioactive cesium contamination, remains a key factor of internal radiation dose forming in residents of the surveyed settlements of Zhytomyr oblast.

RETINA VESSELS CHANGES IN CHORNOBYL NUCLEAR POWER PLANT EMPLOYEES WHO EXPERIENCED LONG-TERM ABNORMAL RADIATION EXPOSURE AT THE WORKPLACE AS A RESULT OF THE OCCUPATION OF CHORNOBYL NUCLEAR POWER PLANT IN 2022. / ZMINY SUDYN SITKIVKY V SPIVROBITNYKIV ChORNOBYL'S'KOÏ ATOMNOÏ ELEKTROSTANTsIÏ, IaKI ZAZNALY TRYVALOGO NENORMOVANOGO RADIATsIINOGO VPLYVU NA ROBOChOMU MISTsI VNASLIDOK OKUPATsIÏ ChAES U 2022 ROTsI.

During the occupation of the Chornobyl Nuclear Power Plant (ChNPP) in 2022, a group of employees remained in the working town for a long time. These personnel were exposed to long-term radiation and non-radiation factors of the production environment, as well as stress and other factors. These factors could result in negative changes of health.It is known that radiation exposure causes changes in the course and caliber of retinal vessels. OBJECTIVE: to assess the condition of retinal arteries and veins and the level of incorporated 137Cs content in persons who were exposed to prolonged exposure to radiation and non-radiation factors of industrial environment, as they were at the workplace overtime during the occupation of the Chornobyl Nuclear Power Plant in 2022. MATERIALS AND METHODS: A comprehensive ophthalmological examination was carried out. Which included the determination of the diameter of the retinal arteries and veins, the arteriovenous ratio, of 55 people from among the personnel of the ChNPP, who worked under the conditions of the occupation of the ChNPP. All those examined were examined on an expert human radiation counter. The results of the ophthalmological examination were compared with the results of earlier examinations of ChNPP employees of the same age groups. RESULTS: It was established that in the examined group, a decrease in the arterio-venous ratio was observed, mainly due to the expansion of retinal veins. Dilatation of the veins was asymmetric, mainly the branches of the central vein of the retina of the right eye were more dilated. Retinal arteries were narrowed in all examined subjects. When comparing the results with the data of previous examinations, it was established that the arterio-venous ratio in this group was probably lower than in previously examined employees of the ChNPP of the same age groups. At the same time, the maximum registered value of the content of incorporated 137Сs was 713 Bq/organism, none of the examined exceeded the control level of 1,000 Bq/organism. CONCLUSIONS: Violation of blood circulation in the retina was detected - a probable increase in the arteriovenous ratio due to the expansion of the retinal veins in the personnel of the Chornobyl nuclear power plant who worked under the conditions of the occupation of the ChNPP in 2022. Since the examined subjects did not exceed the control level of incorporated 137Сs content (1,000 Bq/organism), the observed effect may be a consequence of the influence of other, both radiation and non-radiation factors.

COMPREHENSIVE RADIATION AND HYGIENIC MONITORING IN POPULATION OF THE RIVNE OBLAST RADIOLOGICALLY CONTAMINATED TERRITORIES. / KOMPLEKSNYI RADIATsIINO/GIGIIeNIChNYI MONITORYNG MEShKANTsIV RADIOAKTYVNO ZABRUDNENYKh TERYTORII RIVNENS'KOÏ OBLASTI U 2020 r.

OBJECTIVE: The key factors identification in radiation dose formation in population of radiologically contaminatedareas of Rivne oblast in the current period of accident through comprehensive radiation and hygienic monitoring inreference settlements in 2020 and estimation of their impact on dose formation were the study objectives. MATERIALS AND METHODS: Comprehensive radiation and hygienic monitoring of settlements in Rivne oblast(province) was provided in Stare Selo, Vezhytsia, Perekhodychi, and Drozdyn villages of Rokytne district, where thehighest radiation doses were registered after the ChNPP accident. Studies were conducted in September 2020.Measurements (n=696, 318 adults, and 378 children) were performed using the whole body counters (WBC) to deter-mine the internal radiation doses. The 48 samples of milk, 45 samples of potatoes and vegetables, and 35 samplesof wild products were collected in local farms and measured for the 137Cs and 90Sr content. Residents of the studiedsettlements (n=229, 140 adults, and 89 children) were interviewed about the levels of consumption of staple food-stuffs. External radiation doses were evaluated in all the studied settlements. Mathematical, dosimetric, and radio-chemical methods were applied. RESULTS AND CONCLUSIONS: Annual effective radiation doses of the Rivne oblast population in 2020 were formedmainly due to internal radiation ones that not exceeded 1.24 mSv · year-1 in adults and 0.65 mSv · year-1 in childrenagainst the RCT criterion of 1 mSv · year-1. Further 1.2-1.9-fold decrease in the annual internal radiation doses vs.the results of WBC-monitoring in autumn of 2017 was registered in the surveyed settlements. The latter confirmeda time pattern of radiation levels gradual reduction at the current stage of Chornobyl accident since 2011. Intakeof 137Cs with milk and wild mushrooms, which traditionally occupy a significant part of diet in the Rivne Polissya areaand have consistently high levels of radioactive cesium contamination, remains a key factor of internal radiationdose forming in residents of the surveyed settlements of Rivne oblast.

Injection of Multipotent Mesenchymal Stromal Cells as a Cause of Hemorrhages in the Regional Lymph Nodes: Experimental Study.

Hemorrhagic changes after subcutaneous injection of autologous bone marrow multipotent mesenchymal cells with transfected GFP gene and additionally stained cell membranes to WAG rats in the projection of ligated femoral vein were studied by fluorescent microscopy. Hemorrhages in tissues with experimental acute local venous occlusion were caused by a combination of venous hypertension with inflammation around the foreign body - the ligature used for ligation of the vein. Fibrin found in tissues together with erythrocytes in the hemorrhages could stimulate the formation of granulations and new vessels instead of damaged or thrombosed ones. Multipotent mesenchymal stromal cells and their detritus getting into the regional lymph nodes initiated immune reactions morphologically confirmed by stubborn hypertrophy and hyperplasia of the lymphoid nodules, hemorrhages, and manifest diapedesis of erythrocytes to the organ parenchyma and sinus system.

Some Peculiarities of Local Distribution of Multipotent Mesenchymal Stromal Cells after Their Injection into Intact Muscle Tissue in Experiment.

Changes in the muscular tissue after subcutaneous injection of autologous bone marrow multipotent mesenchymal stromal cells transfected with GFP gene and additionally stained with cell membrane dye Vybrant CM-Dil in the projection of ligated femoral vein were studied by light microscopy with luminescence. Stromal cells injected through the skin can appear not only in the damaged tissue where acceleration of regeneration processes is required, but also in intact structures located in superficial or deeper layers. In intact muscular tissue, stromal cells spreading in the perivascular tissue initiate inflammation and migration of macrophages, activate and even trigger sclerotic processes due to differentiation into connective tissue cells (fibroblasts) and stimulation of proliferation and collagen synthesis by host fibroblasts. Injected multipotent mesenchymal stromal cells are gradually phagocytized by macrophages.

Results of Experimental Ligation of the Main Vein with the Use of Cell Technologies.

Autologous multipotent mesenchymal stromal cells (MMSC) of bone marrow origin with transfected GFP gene and additionally stained cell membranes were injected to rats through the skin in the projection of ligated femoral vein. The results were evaluated by fluorescent microscopy. No signs of MMSC incorporation into the wall of ligated vessel or reorganized collaterals were detected. Angiogenesis processes involving MMSC were detected in experimental rats within just 4 days and progressed until week 2 postinjection, mainly in granulations at the site of surgical intervention and the cicatrix forming there. Injected MMSC completely formed all tunics of the new vessels and incorporated in the vessels forming from the recipient cells. MMSC and the objects created from them were gradually eliminated with participation of macrophages and replaced by structures formed from the recipient cells.

Possibility of Aggravation of Tissue Sclerosis after Injection of Multipotent Mesenchymal Stromal Cells Near the Forming Cicatrix in the Experiment.

The peculiarities of tissue sclerosis after injection of autologous bone marrow multipotent mesenchymal stromal cells transfected with GFP gene and stained with Vybrant CM-Dil cell membrane dye were studied by light microscopy with luminescence. The surgical intervention consisting in ligation of the great vein was followed by tissue sclerotic transformation caused by direct damage and chronic inflammation caused by the presence of slowly resorbed ligature. Injection of stromal cells after this intervention led to formation of more extensive scar. This can attest to the possibility of stromal cells differentiation into connective tissue cells, fibroblasts, and stimulation of proliferation and collagen synthesis by host fibroblasts. A decrease in the volume of dense fibrous connective tissue due to scar reorganization at latter terms cannot not excluded.

Initial Stages of Angiogenesis after Acute Experimental Local Venous Outflow Disturbances and Application of Cell Technologies.

The initial stages of angiogenesis in rats after transcutaneous injection of autologous bone marrow multipotent mesenchymal stromal cells transfected with GFP gene and stained cell membranes in the projection of ligated femoral vein were studied by fluorescent light and confocal laser microscopy. Large clusters of brightly fluorescing elongated fibroblast-like cells were seen in the paravasal tissue and in the postoperative scar and signs of angiogenesis were noted as soon as in 4 days. The injected cells not only formed new vessels, but also integrated into vessels formed by host cells. Some injected cells were phagocytizied by macrophages and the latter started to fluoresce due to the presence of the membrane dye. These macrophages within the specified period appeared in the regional inguinal lymph nodes where they formed clusters in the lymphoid parenchyma of the cortical substance.

Possibility of Using Mesenchymal Stromal Cells to Restore Lymph Flow in Experimental Phlebothrombosis.

The possibility of formation of lymphatic vessels after introduction of autologous bone marrow-derived multipotent mesenchymal stromal cells transfected with GFP gene into thrombosed femoral vein was studied by fluorescent microscopy. Vascular thrombosis caused by ligation of the great vein with subsequent injection of thrombin solution was accompanied by blockade of regional lymph flow. The cells injected into thrombosed vein directly participate in the formation of new lymphatic vessels in the paravasal tissue surrounding the vein, its tissue region, and around regional lymph nodes. This is seen from bright specific fluorescence of individual cells in the walls of lymphatic vessels and all vascular layers and valves in UV light.

[ANGIOGENESIS IN THE TISSUES AFTER THE INJECTION OF STROMAL STEM CELLS OF BONE MARROW ORIGIN CLOSE TO THROMBOSED VEIN IN AN EXPERIMENT].

The effects of the injection of autologous multipotent stromal stem cells of bone marrow origin (MSSCBM) (mesenchymal stem cells) with green fluorescent protein gene, additionally marked with DAPI nuclear stain, close to a thrombosed hindlimb vein, were studied by fluorescent microscopy in adult male Wag rats (n = 214). The control groups consisted of intact rats (n = 12), animals with venous thrombosis without the injection of MSSCBM (n = 71) and rats that received paravasal injection of MSSCBM, but without preliminary modeling of venous thrombosis (n = 72). It was found that MSSCBM participated in the development of granulation tissue at the site of surgical intervention performed during the modeling of thrombosis. The rapid development of granulation tissue at the site of surgical trauma may contribute to faster wound clearance from detritus, nonviable tissue and antigenic substances, early onset of tissue repair processes and rapid healing. Restoration of blood flow in the tissue region of a thrombosed vein began later than after the intravenous injection of MSSCBM.

Acceleration of Angiogenesis after Paravasal Injection of Mesenchymal Stem Cells at the Site of Modeled Venous Thrombosis.

The results of transplantation of autologous bone marrow multipotent mesenchymal stem cells carrying GFP gene and labeled with cell nucleus-specific dye DAPI near the thrombosed vein in rat hind limb were studied by methods of luminescent microscopy. It was demonstrated that autologous multipotent mesenchymal stem cells participate in the formation of granulations at the site of surgery. The blood fl ow in the thrombosed great vein was always restored through thrombolysis. We observed no signs of incorporation of the transplanted cells into the wall of the great vessel, clot recanalization, or formation of collaterals. Small branches of the great vein in the affected region were also thrombosed. The blood fl ow in these branches was always restored with participation of the transplanted cells or through clot recanalization or through obliteration of the thrombosed vessels and formation of new vessels. The transplanted cells and structures formed by them were gradually replaced by the recipient cells.

[MORPHOLOGICAL CHANGES AFTER THE USE OF MULTIPOTENT STROMAL CELLS OF BONE MARROW ORIGIN TO RESTORE THE LYMPH FLOW IN THE REGION OF THROMBOSED VEIN].

In the male Wag rats aged 6 months with the body mass of 180-200 g the luminescent microscopy was used to examine the possibility of lymphatic vessel formation after injection into thrombosed vein of the thigh of autologous multipotent stromal cells of bone marrow origin (AMSCBMO) transfected with green fluorescent protein gene. Animals were sacrificed 4 days and 1, 2, 3, 4 and 5 weeks after the injection of AMSCBMO. The control group consisted of intact rats, animals with venous thrombosis receiving no injection of AMSCBMO and those injected with AMSCBMO but without the prior modelling of venous thrombosis. In each experimental and control groups at each time point 11-12 animals were used (total number equal to 226). After the main vein ligation with the subsequent injection of thrombin solution, in addition to the thrombosis of the blood vessels, morphological signs of thrombosis of the lymphatic bed and lymphostasis were present: the dilation of lymphatic vessel lumen, thinning of their layers, intense staining of their luminal heterogeneous content. AMSCBMO, injected into thrombosed vein, were found to directly participate in lymphangiogenesis in the connective tissue around vein, its tissue region and in the area of regional lymph nodes. This is indicated by bright specific luminescence of both individual cells in the wall of the lymphatic vessels, and all their tunics together with the valves, when exposed to UV light.

[Peculiarities of angiogenesis after the implantation of polyhydroxyalkanoate films with the adsorbed multipotent stromal stem cells of a bone marrow origin].

The processes developing in various rat tissues after implantation of polymeric polyhydroxyalkanoate (PHA) film fragments with adsorbed autologous multipotent stromal (mesenchymal) cells of bone marrow origin (AMMSCBM), were studied by methods of light microscopy. After the implantation of PHA film with AMMSCBM, the number of blood vessels in the surrounding tissues was found to increase as a result of neoangiogenesis. In this case,AMMSCBM did not migrate and were not destroyed at the place of injection, but differentiated into the cells forming blood vessel structures. The processes of angiogenesis in the tissues around PHA implant, in turn, lead to development of a larger number of blood vessels in the granulations formed around the implanted foreign body, higher volume of granulations proper and subsequent development of a thicker capsule delimiting polymer implant.

Reaction of the rat tissues to implantation of polyhydroxyalkanoate films and ultrafine fibers.

The reaction of various tissues of rats to implantation of polyhydroxyalkanoate films and ultrafine fibers was studied by optic microscopy. Implantation of polyhydroxyalkanoate films into the abdominal cavity caused a peritoneal reaction, leading after 1 month to the formation of fibrous adhesions between polyhydroxyalkanoate and intestinal loops. Under the skin and in the muscle tissue polyhydroxyalkanoate films were encapsulated in a thick fibrous capsule. Implantation of polyhydroxyalkanoate ultrathin fibers led to formation of foreign body granulomas in all tissues with perifocal inflammation and sclerosis of the adjacent tissues. The polymer was fragmented in these granulomas and phagocytosed by macrophages with the formation of giant foreign body cells. Hence, polyhydroxyalkanoate materials implanted in vivo caused chronic granulomatous inflammatory reaction and were very slowly destroyed by macrophages.

[Morphological results of stromal stem cells of bone marrow origin into the thrombosed vein in experiment].

Using the methods of luminescent microscopy, the results of injection of autologous multipotent stromal (mesenchymal) stem cells of bone marrow origin (SSCBMO) containing GFP gene, into thrombosed hindlimb vein were studied in 226 male Wag rats. It was found that the restoration of blood flow through the thrombosed main vein was not always the result of thrombolysis. No signs of incorporation of injected SSCBMO into the wall of thrombosed vessel, clot recanalization or collateral formation were detected. In experimental thrombosis model with thrombin administration and main vein ligation, the thrombosis of its small branches also took place. The restoration of blood flow occured via either blood clot recanalization or obliteration of thrombosed vessels and the outgrowth of the new ones. SSCBMO were found to participate in both of these processes resulting in faster restoration of a blood flow in the tissue microregion of thrombosed vein. Gradually the injected SSCBMO and the structures formed with their participation, were replaced by the own cells of a recipient organism.