EFFECT OF IRON ON BONE TISSUE METABOLISM AND THYROID FUNCTION IN CHILDREN LIVING ON RADIOLOGICALLY CONTAMINATED TERRITORIES SINCE THE ChNPP ACCIDENT

OBJECTIVE

identification of clinical and metabolic characteristics of osteogenesis and factors affecting bone mineral density (BMD) in children living in radioactively contaminated territories (RCT) after the ChNPP accident for the use of therapeutic and preventive measures aiming to reduce the incidence of disorders.

MATERIALS AND METHODS

Children aged 4 to 18 years old (n = 539) were involved in the study within 4 age groups, namely under 7 years old, 7-10 years old, 10-14 years old, older than 14 years old. Studied parameters in children with a reduced BMD (85-65 relative units and under 65 relative units) were estimated vs. the normative BMD (100-85 relative units) cases. Diagnosis of osteopenia and osteoporosis in children was established according to the BMD T-index. Family history of the relatives of children was studied. Body weight at birth, fractures of the long bones, complaints of osalgia, jaw anomalies, dental caries, presence of obesity, and hypermobility syndrome (HMS) were assessed. Peripheral blood biochemical tests were performed featuring the serum total protein, alkaline phosphatase (APh), calcium, vitamin D, creatinine, serum iron (SI), ferritin, cortisol, pituitary thyroid-stimulating hormone (TSH), and free thyroxine (FT4) assay. BMD was measured and radiation doses in children were reconstructed.

RESULTS

BMD depended on the age of children. A direct correlation was established between the cholelithiasis and urolithiasis incidence (р < 0.01), cancer and endocrine diseases (р < 0.05) in the relatives of children that had BMD under 65 relative units. Dental caries developed more often (р < 0.05), while obesity was less frequent (р < 0.05) in the subjects with BMD < 65 relative units. A direct correlation was established between the level of serum creatinine and BMD (р < 0.01), and there was an inverse correlation between the serum APh level and BMD (р < 0.001).Every third child had a vitamin D deficiency. Fractures of long bones and increased content of SI and TSH were characteristic for the children having got osteopenia (BMD within 85-65 relative units), while besides a predisposition to bone fractures the higher levels of SI, APh, cortisol both with calcium deficiency were found in children with osteoporosis (BMD < 65 relative units) compared to the general group with a similar BMD. An increased incidence of HMS was characteristic too. Radiation doses in children with osteopenia were higher than in those with osteoporosis: (1.17 ± 0.09) mSv and (0.92 ± 0.06) mSv respectively (р < 0.05). No correlation was found between the radiation doses and clinical signs, blood biochemistry or BMD.

CONCLUSIONS

Study of the functional mechanisms of bone structures in children, depending on their metabolism, had made it possible to reveal the factors that affect bone formation in children living in RCT after the ChNPP accident, and to form the population groups for the timely application of therapeutic and preventive measures aiming to reduce the incidence of disorders of musculoskeletal system.

DRIVERS OF HYPERFERREMIA IN CHILDREN LIVING ON RADIOLOGICALLY CONTAMINATED TERRITORIES AFTER THE CHNPP ACCIDENT IN UKRAINE

OBJECTIVE

assessment of clinical-hematological and metabolic-biochemical parameters of the of bone tissue and hormonal regulation depending on the serum iron content and radiation dose values in children living on radiologically contaminated territories after the ChNPP accident in Ukraine.

MATERIALS AND METHODS

Children (n = 271) living on radiologically contaminated territories (RCT) of Ukraine were involved in the study. Three study groups were formed according to the serum iron level (SIL), namely group I with SIL 10.0-22.0 μmol/l (n = 92), group II with SIL 23.0-34.0 μmol/l (n = 144), and group III with SIL above 35.0 μmol/l (n = 35). Diseases in the family tree, bodyweight at birth, complaints on osalgia, bone fractures, jaw anomalies, dental caries, and obesity were accounted. Morphometric parameters of erythrocytes and hemogram elements were analyzed. Creatinine, alkaline phosphatase, calcium, total protein, iron, cholesterol, bilirubin, and transaminases were assayed in blood serum. The urine content of the 19 free amino acids, serum content of the free thyroxine (FT4), pituitary thyroid-stimulating hormone (TSH), and cortisol were assayed both with bone tissue density. Individual radiation doses were calculated.

RESULTS

In 12.9 % of cases the SIL was > 35.0 μmol/l. Relatives with endocrine diseases were often present in the family tree of children with SIL > 23.0 μmol/l. There were increased urine content of the free amino acids (p < 0.05) and signs of protein degradation under high SIL. Contents of amino acids involved in collagen synthesis and antioxidant status (alanine, serine, glutamine, aspartic acid) and iron metabolism (arginine, leucine) were assayed at the highest levels (p < 0.05). Urinary levels of valine, lysine, and methionine, which are associated with iron metabolism, were decreased (p < 0.05). An inverse correlation (rs = -0.58; p < 0.01) was established between the serum TSH and cortisol levels regardless of the SIL. Serum TSH level directly correlated with urine content of amino acids involved in collagen synthesis. An inverse correlation (rs = -0.55; p < 0.001) was established between the serum TSH level and urine content of tyrosine that is essential for the thyroid hormone (triiodothyronine and thyroxine) synthesis.Cortisol was found having a negative effect on protein synthesis. Inverse correlation was established between the serum cortisol level and urine content of the free amino acids essential for collagen synthesis. There was no dependence of the average radiation dose values on the SIL. An inverse correlation was determined between the patient's radiation dose and SIL > 35.0 μmol/l (rs = -0.29; p < 0.05).

CONCLUSIONS

The increased SIL in children living on RCT may occur due to both a genetic predisposition and the acquired factors driving protein and mineral metabolism of bone and their hormonal regulation.

THYROID DISEASE IN THE LATE OBSERVATION PERIOD UPON CHEMO AND RADIOTHERAPY IN CHILDREN/SURVIVORS OF ACUTE LYMPHOBLASTIC LEUKEMIA

OBJECTIVE

to assess the thyroid disease in the late observation period in children who had received chemo- andradiotherapy for the acute lymphoblastic leukemia (ALL) taking into account gender, age period and disease sub-type.

MATERIALS AND METHODS

The incidence and nature of thyroid disease (hypothyroidism, thyroiditis, and thyroid can-cer) were studied in children-survivors of acute lymphoblastic leukemia (ALL) being in remission from 6 to 25 years.The distribution of patients by leukemia subtypes was as follows: «common» - 67.4 %, pre-B - 23.9 %, pro-B andT-cell - 4.3 %. Children had been receiving chemo- and radiotherapy according to the protocol. Regarding the ageof patients at the time of ALL diagnosis the prepubertal, pubertal and postpubertal periods were taken into account.The endocrine diseases in family history, body weight at birth, serum content of free thyroxine, pituitary thyroid-stimulating hormone, cortisol, iron, ferritin and thyroperoxidase antibodies were evaluated and assayed.

RESULTS

Thyroid disease in children was emerging in the first 2-3 years after the ALL treatment with an incidenceof 22.8 % (hypothyroidism - 14.1 %, autoimmune thyroiditis - 7.6 %, papillary cancer - 1.1 %). Seven children inthis group had received radiotherapy (12-18 Gy doses) on the central nervous system (CNS). No correlation wasfound between the radiation exposure event itself, radiation dose to the CNS and thyroid disease in the long-termfollow-up period. Thyroid cancer had developed in a child 11 years upon chemo- and radiotherapy. Hypothyroidismwas more often diagnosed in the patients of prepubertal age (rs = 0.49). There were endocrine diseases in thefamily history in about a half of children, being significantly higher than in the general sample (р < 0.05). The bodyweight at birth of a child who had later developed hypothyroidism was less than in children having got thyroiditis(rs = 0.57).

CONCLUSIONS

Disorders in endocrine regulation and of thyroid in particular can affect the prognosis of blood can-cer course in the long-term follow-up in children, especially in prepubertal age, which requires systematic supervi-sion by hematologist and endocrinologist.

FEATURES OF CLINICAL SYMPTOMS AND SIGNS, HEMATOLOGICAL AND BIOCHEMICAL PARAMETERS IN CHILDREN WITH JOINT HYPERMOBILITY IN A LATE PERIOD UPON THE CHORNOBYL NPP ACCIDENT

OBJECTIVE

establishing the types and frequency of disembriogenetic stigma in children with joint hypermobility given the clinical and laboratory features, genetic component and endocrine regulation of these disorders in a late period upon the accident.

MATERIALS AND METHODS

Children (n = 109) inhabiting the radiologically contaminated territories and having the connective tissue dysplasia (CTD) signs were involved in the study. Diseases in family history, ossalgia complaints, fractures in a personal history, bone disembriogenetic stigma, joint hypermobility, type of somatic diseases, blood serum biochemical parameters (namely calcium, alkaline phosphatase, total protein, cholesterol, creatinine, iron, ferritin content), serum cortisol, free thyroxine, pituitary thyroid-stimulating hormone (TSH) levels, free amino acid composition in urine and radiation dose were considered.

RESULTS

Radiation doses in children having the CTD ranged from (0.37 ± 0.11) mSv to (0.56 ± 0.10) mSv with no difference from that in those without CTD. Joint hypermobility (JHM) correlated with cancer in family history (rs = 0.53) and lower extremity varicose vein disease (rs = 0.40) (p < 0.05). Incidence of ossalgia, easy fatigability, and bone fractures was higher in children with CTD. Anomalies of the dentofacial system were first in line (38.5 %) in these children. Proportion of children with grade II JHM and platypodia was lower (rs = 0.42), but with lower extremity deformations was higher (rs = 0.68) (p < 0.05) vs. in the control group. Iron and ferritin deficiencies both with lymphocytosis were more common in children with CTD than in the comparison group (p < 0.05). The increased content of oxyproline, lysine, proline both with glycine deficiency were detected in children having the CTD, i.e. an imbalance of amino acids from the collagen content was observed featuring a predominance of catabolic processes over anabolic ones. There was a direct correlation between the TSH level and the JHM grade (rs = 0.49), although the values of hormone concentration in these children did not exceed the reference range (maximum values were 3.3 μIU/ml).

CONCLUSIONS

The revealed abnormalities in amino acid content, ferrokinetics, and thyroid function indices can affect the collagen formation, organic matrix structure of bone tissue and significantly deregulate the hemato- poiesis. The later can underlie the pathways of haematologic malignancy development.

[Heterogeneity of chromosomal abnormalities in acute myeloid leukemia in different age groups children]

Characteristic of chromosomal abnormalities in bone marrow cells among 123 children with acute myeloid leukemia were presented according five aging groups: I - up to 2 years, II - 2-5 years, III - 5-10 years, IV - 10-15 years, V - 15-18 years. Normal karyotype wasn't found in group up to 2 years and in low presented in another groups (5, 9-10,3%). The highest frequency of chromosomal abnormality evolution in group up to 2 years was established (69,2%). The highest frequency of hyperdiploidy (47-50 chromosomes) in group 15-18 years (31%) was found. More often near-tetraploidy and pseudodiploidy clones were met in group 2-5 years (47% and 58,8%, respectively). Between structural types in all groups were predominated translocations and deletions. In group up to 2 years was prevalented translocations (61,5%), 2-18 years - deletions (64,7; 34,5; 45,7 and 41,4 % respectively). In group up to 2 years more often were met abnormalities chromosomes (Chr) 9, 11, 16 (in 30,8%), 2-5 years - Chr 16, 21 (in 29,4%), 5-10 years - Chr 11 (24,1%), 8, 15, 17 (in 17,2%), 10-15 years - Chr 16 (40%) and 15-18 years - Chr 8, 9, 15, 17 (in 17,2%).

[Phenomenon of the evolution of clonal chromosomal abnormalities in childhood acute myeloid leukemia]

Analysis of chromosomal abnormalities in bone marrow cells in 116 children with diagnosis of acute myeloid leukemia (AML) was performed. Frequency of evolution of clonal chromosome abnormalities in AML constituted 42,3%. The most abundant among them were numerical abnormalities of chromosomes 8, 9, and 21 as well as secondary structural abnormalities in region 12p12, 9p22, 9q22, 9q34, 11q14-23, and 16q22. Numerical abnormalities were registered in 26,7% cases. The basic mechanism of leukemic clone evolution was trisomy, deletion and monosomy. The frequency of evolution was 7 times higher in the age group up to 2 years and twice higher in the age group up to 5 years. The high frequency of evolution was established at t(15;17)(q22;q22) and the absence at inv(16)(p13q22). The patients with clonal evolution died earlier, before reaching remission, that can be connected with heavy initial state and high frequency of relapse. Conception of abnormality clone evolution was proposed at some stages: I--appearance of balanced rearrangement; II--trisomy; III--lose of chromosomal material. Appearance of unbalanced genome in evolution possess an advantage in proliferate activity and can be connected with the answer on chemotherapy. Identity of abnormal chromosome structure at diagnosis and relapse of disease can be an evidence of the influence of chemical agent on establishment of some types of evolution of chromosome abnormalities in leukemic cells in AML in children.

[Rearrangements of chromosome 9 in different hematological neoplasia]

The frequencies of chromosome 9 abnormalities in children with hematological neoplasia have constituted: 25/112 in acute lymphoblastic leukemia (ALL), 10/83--in acute myeloid leukemia (AML), 3/20--in refractory anemia (RA). The frequency of deletions was higher than of translocations in ALL. Deletions were found as sole abnormalities as in complexity karyotypes. More often the rearrangements affected bands 9q34 and 9q22. Translocation t (9;22)(q34; q11) occured in 7.1% cases ALL. In AML the translocations were detected with greater frequency than deletions. The long arm bands 9q22 and 9q34 were more often involved in structural rearrangements. Deletions, translocations and duplications were registered in MDS. Comparison with clinical features showed no correlation with age and the main hematological indexes including the amount of blast cells in initial period. Multidrug resistance and disease progression during chemotherapy were noted in t (9;22).