The effect of aminoglycoside administration on kidney functional maturation was evaluated in groups of 30 preterm and 30 fullterm infants who were treated for 7 days because of suspected infection. One of three different aminoglycosides was administered to each subgroup of ten preterm and ten fullterm infants. Changes in tubular function in groups of ten preterm and ten fullterm infants who were not given antibiotics were also compared. The mean gestational age for preterm infants from 32.5 to 33.6 weeks and for fullterm infants between 39.2 and 39.5 weeks. The renal tubular function was assessed by examining the fractional excretion of sodium (FENa), potassium (FEK), phosphorus (FEP), magnesium (FEMg) and uric acid (FEUA) as well as by the urinary excretion of calcium as the calcium/creatinine (UCa/UCr) ratio. Gentamicin affected the normal plasma creatinine (PCr) decline in both treated groups (fullterm and preterm). Disturbances in FENa and UCa/UCr were more pronounced in treated preterm than in fullterm infants especially after netilmicin and gentamicin administration. FEMg was significantly affected in preterm infants treated with gentamicin. The findings of this study indicate that the effect of aminoglycosides on tubular function is dependent upon kidney maturity and the type of the aminoglycoside used for therapy.

Children and adolescents with the high bone turnover comprise a high risk population for vitamin D insufficiency. A sample of 178 clinically healthy children aged 3 to 18 years who came from public schools and lived in North West of Greece participated in the study. They were grouped into three age groups (I: 3-10, II: 11-14 and III: 15-18 years of age). Blood samples were taken during winter and summer months for determining calciotropic hormones, calcium, phosphate and biochemical markers of bone synthesis.A high percentage (47%) of the subjects aged 15-18 years was found to have 25OHD <10 ng/ml in winter but much less (13-14%) of the younger ages (13-14 years), while in the summer they were all >10 ng/ml. The prevalence was even higher in the girls of the older group accompanied by lower Pi concentrations again in winter (win:1.19+/-0.03, sum:1.93+/-0.03 mmol/l, p < 0.001). The 24,25(OH)(2)D levels were changing in parallel to 25OHD, but again in the older subjects, during winter, they were by 2/3 lower than the summer ones (0.73+/-0.10 vs. 2.41+/-0.20 ng/ml, p < 0.001). No significant differences were found between seasons and groups in the 1,25(OH)(2)D levels. The biochemical markers of bone synthesis, osteocalcin (OC) and total alkaline phosphatase (ALP), were found significantly lower in the girls of the older group both in winter and summer respectively. Even in a sunny country like Greece the adolescents living in an urban area are in high risk for vitamin D deficiency during winter. Supplementation with vitamin D of milk, of popular beverages and perhaps some foods would be of help.

The effect of three different aminoglycosides on renal function was evaluated in 30 premature infants of similar gestational age who were treated within 24 h of birth with either amikacin (10 infants, group A), gentamicin (10 infants, group B) or netilmicin (10 infants, group C), for a period of 7 days. Ten infection-free premature infants of similar post-conceptional age were used as controls. Serial determinations of plasma creatinine concentration (PCr), as well as the fractional excretion of sodium (FENa), potassium, magnesium (FEMg), phosphate (FEP) and uric acid (FEUA), and the urinary excretion of calcium (UCa/UCr ratio) were assessed before, during and after treatment. During the treatment period a significant increase in FENa, FEMg and UCa/UCr was observed in group B (P < 0.05 and P < 0.01, respectively) and an increase in FENa and UCa/UCr in group C (P < 0.01) compared with controls. These disturbances were observed with trough concentrations of aminoglycosides but were accentuated at peak serum concentrations and were restored to normal 2 days after stopping therapy. In addition, a significant correlation was demonstrated between FENa, FEMg and UCa/UCr ratio in treated patients. PCr levels decreased similarly in all patient groups, but in 8 of 30 infants (27%) they remained elevated and returned to control values only 10 days after stopping therapy. Such renal functional disturbances, although transient, may result in significant electrolyte and mineral imbalance in the sick premature infant.

Serum IL-4 levels are increased in hospitalized children with symptomatic brucellosis, a finding suggestive of a Th2 response leading to severe infection.

Mechanical stress exerts a substantial role on skeletal-cell renewal systems, whereas accumulating evidence suggests that epigenetic mechanisms induce changes and differential gene expression. Although the underlying mechanisms remain to be fully elucidated, our study suggests that the influence of the long term mechanical stimulation elicits epigenetic modifications controlling osteogenic differentiation of human adipose tissue multipotential stromal cells (hAT-MSCs) and contributes to an accelerating in vitro osteogenesis. GNAS imprinting gene acts as a critical regulator of osteoblast differentiation and is implicated in human genetic disorders with pathological formation of ectopic-skeletal bone. Investigating a wide variety of stimuli, we showed that daily mechanical stretch on hAT-MSCs of 7th and 15th days' intervals induced a significant down-regulation in DNA methylation status of critical CpG sites of NESP and GNASXL isoforms, accompanied by up-regulation of the corresponding gene transcripts, and osteogenic differentiation earlier in culture. Importantly, methylation analysis of differentiating bone marrow-derived MSCs revealed similar methylation patterns. Bioinformatic analysis further showed that all CpG islands exhibiting significant methylation alterations encompassed transcriptional repressor CTCF binding sites. We hereby emphasize the need to investigate the epigenetic alterations on hAT-MSCs during environmental mechanical forces and to consider how the knowledge gained through these studies may foster new means of symptoms prevention and management of ectopic bone formation in the clinic.