Can digital X-ray radiogrammetry be an alternative for dual-energy X-ray absorptiometry in the diagnosis of secondary low bone quality in children?

Bone quality in children is generally measured with dual-energy X-ray absorptiometry (DXA). Digital X-ray radiogrammetry (DXR) uses BoneXpert to measure cortical bone quality on hand radiographs. This prospective study compared DXR and DXA results in children with high probability of secondary low bone quality, defined as DXA of the lumbar spine (DXALS) Z-score ≤ - 2.0. One hundred one children underwent both DXA and DXR assessment. DXALSZ-scores were also adjusted for bone age. DXR Z-scores were compared with both DXALSZ-scores, using Pearson correlations, Bland-Altman analysis, and sensitivity-specificity analysis. Mean bone age, DXR, and both DXA Z-scores were significantly impaired. Pearson correlation coefficients were significant between DXR Z-scores and both DXALSZ-scores 0.507-0.564 (p < 0.001). Bland-Altman analysis showed a mean difference of 0.05-0.48 between DXR and both DXA Z-scores and showed more than 90% similarity for both DXALSZ-scores ≤ - 2.0. DXR had a sensitivity of 67-71% and specificity of 77-83% compared to both DXALSZ-scores.Conclusion: DXR correlates well with as well DXALS as bone age-adjusted DXALSZ-scores and shows good agreement with as well DXALS as bone age-adjusted DXALSZ-scores ≤ - 2.0. DXR shows best results when compared with DXALSZ-scores. What is Known: • Digital X-ray radiogrammetry (DXR) may correlate well with dual-energy X-ray absorptiometry (DXA) in pediatric, adolescent, and adult patients. • DXR is a feasible method for assessment of bone quality in children. What is New: • This is the first prospective study in children with suspected secondary low bone quality that illustrates correlation between DXR and bone age-adjusted DXA Z-scores and that shows good agreement between DXR and DXA as bone age-adjusted DXA Z-scores ≤ -2.0. • Our results suggest DXR to be a good alternative for DXA for determining low bone quality.

Allopurinol and 5-aminosalicylic acid influence thiopurine-induced hepatotoxicity in vitro.

INTRODUCTION: The use of thiopurines is frequently accompanied by hepatotoxicity. Studies on hepatocyte cultures showed a time- and dose-dependent increase of thiopurine toxicity. 5-Aminosalicylic acid (5-ASA) and allopurinol can influence thiopurine metabolism; however, it is unknown whether this affects in vitro cytotoxicity. METHODS: Human hepatoma cells (Huh7, HepG2 and HepaRG) were incubated with increasing concentrations of thiopurines, 5-ASA or allopurinol. Water-soluble tetrazolium salt-1 (WST-1) cytotoxicity assays were used to calculate cell survival curves and half maximal inhibitory concentrations (IC50). Combination experiments with thiopurines with a fixed dose of 200 µM 5-ASA or 100 µM allopurinol were conducted in HepaRG cells. Caspase-3/7 activation was evaluated, and single cell electrophoresis analysis was performed. RESULTS: A time- and dose-related cytotoxic effect was seen with azathioprine (AZA) in all hepatoma cells, whereas Huh7 and HepG2 cells did not show toxicity to 6-mercaptopurine (6-MP). HepaRG cells expressed the highest levels of drug metabolising enzymes, and therefore, combination experiments were conducted in HepaRG cells. Addition of a non-toxic dose of allopurinol resulted in a twofold to threefold increased cytotoxicity of all thiopurines, which seemed to be mediated by apoptosis/DNA damage. CONCLUSION: The addition of allopurinol to thiopurines leads to a two-threefold increased cytotoxicity in HepaRG cells.

[Unexplained cyanosis in two newborns: neonatal methemoglobinemia after maternal perineal infiltration of prilocaine]. / Onbegrepen cyanose bij twee neonaten.

BACKGROUND: Methemoglobinemia is a rare cause of neonatal cyanosis in the newborn. It is considered a medical emergency. Failure of recognition or appropriated treatment could result in serious disease and neonatal death. Neonatal methemoglobinemia can be caused by both hereditary and acquired factors. CASE DESCRIPTION: We present two cases of newborns who developed severe cyanosis a few hours after birth due to methemoglobinemia. This was thought to be related to the local maternal perineal infiltration of prilocaine during childbirth. Though rare, prilocaine is the most potent agent to induce methemoglobinemia compared to other local aneasthetics. After intravenous administration of methylene blue, both newborns fully recovered. CONCLUSION: Neonatal methemoglobinemia is a rare and potentially fatal complication of local anesthetics, particularly prilocaine, administered to the mother during childbirth. Midwives, obstetricians, gynecologists and pediatricians should be aware of this complication. The use of other local anesthetics, including lidocaine, should be considered.