This new UHPLC-MS/MS method is accurate and specific for the measurement of vancomycin starting from small (50 μL) plasma volumes. The use of UHPLC-MS/MS is recommended to prevent a misclassification of therapeutic or toxic vancomycin levels in paediatrics.
Different plasma and urinary parameters have been tested as valuable prognostic markers for children with neuroblastoma (NB), but conclusive results from multivariate analyses are still lacking. Samples collected at diagnosis from 505 patients diagnosed in Italy between June 1994 and November 2010 were analyzed at the Italian reference laboratory according to standard methodologies. Patient clinical data were retrieved from the Italian NB Registry. For statistical analysis, patients were grouped according to stage, age, MYCN status, and outcome. Cumulative survival was calculated by the Kaplan–Meier procedure using the first quartile of the marker distribution as a cut-off value to stratify the patients. Multivariate analysis was performed by the Cox regression model by considering only the significant variables. When the entire cohort of patients was considered, none of the different parameters had an independent prognostic value. However, in patients with localized disease without MYCN amplification the significant positive associations between urinary and plasmatic vanillylmandelic acid (VMA)/homovanillic acid (HVA) ratio and a better prognosis remained significant (P < 0.05 and P < 0.01, respectively), as well as, the positive association between high lactate dehydrogenase (LDH) values and a worse prognosis (P < 0.001). Moreover, in stage 4 patients without MYCN amplification, neuron-specific enolase levels above 200 ng/mL and LDH levels above 2500 IU/mL maintained their significant association with a worse outcome (P = 0.01 and P = 0.0001, respectively). In conclusion, LDH had an independent prognostic value in patients of all stages without MYCN amplification. Moreover, the urinary and plasmatic VMA/HVA ratio was an independent predictor of prognosis in patients with localized disease without MYCN amplification. Since LDH and catecholamine metabolites are measured in all patients at diagnosis, these findings may be helpful for an easy, cost-effective, patient risk stratification.
Background. Classical galactosemia is a rare but very severe disease characterized by a defi ciency of the galactose-1-phosphate uridyltransferase enzyme. The confi rmed galactosemic patients are treated with a galactose-restricted diet. Nevertheless, metabolites such as galactose-1-phosphate can accumulate in red blood cells of treated patients and its measurement is a standard practice for their monitoring. At present, no commercial methods for measuring galactose-1-phosphate in erythrocytes are available. Methods. In this study, we will describe the optimization and laboratory validation of a previously published quantitative gas chromatographic-mass spectrometric method and its clinical validation on normal donors and galactosemic patients both at the diagnosis and during the follow-up . Results. The method was technically optimized and validated for its clinical use on normal donors and galactosemic newborns, children and adults. The method was suitable for the monitoring of dietary compliance. Galactose-1-phosphate levels were found to be well correlated with the clinical signs in the galactosemic patients at the follow-up. Conclusions. This paper provides information on the measurement of Galactose-1-phosphate levels that can be very useful for the management of classical galactosemia.
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