CORRECTION CRITERIA FOR THE BONE TISSUE STRUCTURE DISORDERS IN CHILDREN LIVING IN RADIOLOGICALLY CONTAMINATED TERRITORIES AFTER THE CHORNOBYL NPP ACCIDENT.

Objective: To determine the structure of abnormalities of bone tissue and substantiate the management tactics inacute lymphoblastic leukemia (ALL) pediatric patients and in children with no oncohematological disorders, livingin radiologically contaminated territories (RCT).

Materials and methods: Children (n = 220) living in RCT were the study participants i.e. the ALL patients (n = 120,Group I) and ones with no oncohematological disorders but having got some abnormalities in osteon and ironmetabolism (n = 100, Group II). There were 81.7 % cases of the «common» ALL, 10.0 % of the pro-B-ALL, and 8.3 %of the T-ALL types. Incidence of the bone fractures and jaw anomalies were taken into account. Types ofdiseases/disorders in the children's relatives were identified. The hemogram and myelogram data were evaluated.Biochemical blood parameters, namely the total protein, creatinine, calcium, alkaline phosphatase, serum iron (SI),ferritin (SF), transferrin, and vitamin D serum content along with the amino acid content in urine, bone mineral density (BMD) value, serum level of pituitary thyroid-stimulating hormone (TSH), free thyroxine, and cortisol wereassayed. Individual radiation doses were calculated/reconstructed. Curative and preventive measures were developed and applied.

Results: Collagen degradation, increased urinary excretion of oxyproline and proline, and decreased level of glycineand lysine occurred in the Group I after the chemotherapy (ChT) administration. The number of patients with BMDlower than 65 relative units (RU) was increasing (p < 0.05) as well as the number of cases with body iron excess(41.7 %). Toxic hepatitis and fatal cases were more often observed (p < 0.05 and r = -0.38, p < 0.01 respectively)under the SF level above 500 ng/ml. A direct relationship was established between the serum levels of SF and cortisol (r = 0.55; p < 0.05), between the TSH levels (above 3.3 IU/l) in blood serum and oxyproline in urine (r = 0.39;p < 0.05) negatively affecting the state of collagen. An increased level of cortisol contributed to the abnormalitiesin bone tissue structure and to a worse prognosis of the ALL course (p < 0.01). In the Group II (subjects having gotbone structure abnormalities) the sum amount of amino acids was increased. In 30.0 % of them the SI level exceeded the normative range. Radiation doses were on average (4.5 ∓ 0.9) mSv in ALL patients and (0.78 ∓ 0.07) mSv inthe RCT residents with no correlation with either serum biochemical parameters or BMD values. Curative and preventive measures were aimed at correcting the protein deficiency and mineral component of bone tissue, removingexcess iron from the body, and normalizing of hormonal status. Positive effect was reached in 81.7 % of the ALLpatients 6 months after the end of ChT. Normalization of the studied parameters occurred in 80 % of children having no oncohematological disorders.

Conclusions: Diagnosis of abnormalities in the bone tissue structure and correction of osteogenesis in childrenreveal the mechanisms of leukemogenesis, determine the algorithm for timely approaches in prevention of bloodsystem diseases, and improve the quality of life of children.