Effect of 1,25(OH)2-vitamin D on bone mass in children with acute lymphoblastic leukemia.

BACKGROUND: Calcitriol deficit has been described in patients with acute lymphoblast leukemia (ALL). The aim of this randomized case-control trial is to investigate the effectiveness of calcitriol administration during the first year of treatment to protect bone mass. Sixteen children recently diagnosed with ALL, aged 1.7 to 11.5 years, average 5.5, completed the study. Anthropometrical measurements, food intake record, physical activity, and bone pain were registered. Dual energy x-ray absorptiometry was performed at the completion of remission induction chemotherapy (after 1 mo) to measure bone mineral density (BMD) at hip, lumbar spine and whole body, and total bone mineral content and 1 year after. Half of them were randomly assigned to receive calcitriol during 1 year. STATISTICAL: Kruskal-Wallis, Wilcoxon, Mann-Whitney, and Spearman. RESULTS: Both groups had similar anthropometric measurements and bone densitometric variables increments. Spine BMD significantly increased in calcitriol supplemented children with lower baseline BMD (r=-0.78 and P<0.05). CONCLUSIONS: One-year calcitriol administered to recently diagnosed ALL children did not show impact on bone mass. Greater increment in lumbar spine bone mass was observed in patients who received calcitriol and had lower baseline BMD.

Normalización de la densidad mineral ósea en niños nacidos prematuros en Viña del Mar, Chile / Normalization of bone mineral density in premature-born children from Viña del Mar, Chile

Background: In a previous study we reported that healthy children born at 34 or fewer gestational weeks, with adequate weight for gestational age, had not completed their bone catch-up at mean age of 6.3 years. Aim: This is a follow up report, performed on the same population one year later to determine at which age premature - born children achieve their bone mineral density (BMD) catch-up, compared to term-born controls. Material and methods: Fifteen children mean age 7years 3 months, born at 25 to 34 weeks of gestation, with a birth weight of 740 to 2.200 g were studied Radius, lumbar spine and femoral neck bone mineral density, whole body bone mineral content and body composition were assessed by DEXA. Results: Height, body mass index, peripheral BMD, axial BMD, fat and lean body mass in these children were not different from term born controls. Conclusions: Premature born children with adequate weight for gestational age, achieved peripheral and axial bone mineral density catch-up at the age of 7 to 8 years.

[Normalization of bone mineral density in premature-born children from Viña del Mar, Chile]. / Normalización de la densidad mineral ósea en niños nacidos prematuros en Viña del Mar, Chile.

BACKGROUND: In a previous study we reported that healthy children born at 34 or fewer gestational weeks, with adequate weight for gestational age, had not completed their bone catch-up at mean age of 6.3 years. AIM: This is a follow up report, performed on the same population one year later to determine at which age premature - born children achieve their bone mineral density (BMD) catch-up, compared to term-born controls. MATERIAL AND METHODS: Fifteen children mean age 7 years 3 months, born at 25 to 34 weeks of gestation, with a birth weight of 740 to 2.200 g were studied Radius, lumbar spine and femoral neck bone mineral density, whole body bone mineral content and body composition were assessed by DEXA. RESULTS: Height, body mass index, peripheral BMD, axial BMD, fat and lean body mass in these children were not different from term born controls. CONCLUSIONS: Premature born children with adequate weight for gestational age, achieved peripheral and axial bone mineral density catch-up at the age of 7 to 8 years.

[Bone mineral density in school age children born preterm ]. / Densidad mineral ósea en escolares nacidos prematuros.

BACKGROUND: The age at which children born preterm normalize their bone mineral density, is not well known. AIM: To study if children born preterm have normalized their bone mineral density at age 5 to 7 years. PATIENTS AND METHODS: Twenty six infants born preterm (14 male), were studied at age 5 to 7 years. Birth weight, present weight and height, bone age, calcium and phosphate intake at the first year of life and at the current age were assessed. Bone mineral density was measured by single photon X ray absorptiometry in the dominant forearm. A blood sample was obtained to measure insulin growth factor 1 (IGF-1). As a control group, 105 healthy age-paired infants born at term, were studied. RESULTS: Bone mineral density was significantly lower in infants born preterm than in their term counterparts (0.273 +/- 0.01 g/cm2 and 0.302 +/- 0.01 g/cm2 respectively, p < 0.001). There was a positive correlation between bone mineral density and IGF-1 (r = 0.49, p = 0.01). No correlation with the other measured parameters was observed. CONCLUSIONS: Infants that were born preterm have a lower bone mineral density at 5 to 7 years of age than their term controls. Bone mineral density correlates with IGF-1.

[Clinical and molecular genetic study of cystic fibrosis in the 5th Region of Chile]. / Estudio clínico-genético molecular de la fibrosis quística en la V Región, Chile.

BACKGROUND: Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasian population. More than 900 mutations have been detected in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene. The most common worldwide, is a deletion of phenylalanine 508 (delta F508). AIM: To analyze the presence of mutations delta F508, G542X, N1303K, G551D, R553X and S549N in patients from the 5th Region of Chile, with a clinical diagnosis of CF. PATIENTS AND METHODS: We studied 17 non-related patients, presenting frequent respiratory tract infections, malabsorption and positive sweat tests, or meconial ileum. Serum immunoglobulins (IgG, IgA, IgM), and total, CD3+ and B-lymphocytes, were determined to discard the presence of an immune deficiency. The molecular study of the gene was performed by Polymerase Chain Reaction amplification and restriction analysis. RESULTS: Immunological parameters were normal in all patients. The delta F508 mutation was detected in 11 chromosomes and the mutation G542X in 3 chromosomes. CONCLUSIONS: The mutation G542X was the second most frequent mutation found in this sample of Chilean CF patients. Since this mutation has a high frequency in Spanish CF patients, we suggest that this mutation might have had its origin in Spain.