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Background Bortezomib is a proteasome inhibitor currently studied in clinical trials of childhood cancers. So far, no side effects on bone growth have been reported in treated children. However, bortezomib was recently found to induce apoptosis in growth plate chondrocytes and impair linear bone growth in treated mice. We hypothesize that [Gly14] humanin (HNG), a 24-amino acid synthetic antiapoptotic peptide, can prevent bortezomib-induced bone growth impairment. Methods Mice with human neuroblastoma or medulloblastoma tumor xenografts (9-13 animals/group) received one 2-week cycle (2 injections/week) of bortezomib (0.8 mg/kg or 1.0 mg/kg), or HNG (1 µg/mouse), or the combination of HNG/bortezomib, or vehicle. Cultures of human growth plate cartilage, chondrogenic- and cancer cell lines, and immunohistochemistry for detection of proapoptotic proteins were also used. Statistical significance was evaluated by two-sided Mann-Whitney U test or by parametric or nonparametric analysis of variance. Results Bortezomib efficiently blocked the proteasome and induced pronounced impairment of linear bone growth from day 0 to day 13 (0.09 mm/day, 95% confidence interval [Cl] = 0.07 to 0.11 mm/day; vs 0.19 mm/day, 95% Cl = 0.15 to 0.23mm/day in vehicle; P< .001), an effect significantly prevented by the addition of HNG (0.15ram growth/day, 95% CI = 0.14 to 0.16mm/day; P< .001 vs bortezomib only; P= 0.03 vs vehicle). Bortezomib was highly toxic when added to cultures of human growth plate cartilage, with markedly increased apoptosis compared with control (P < .001). However, when combining with HNG, bortezomib-induced apoptosis was entirely prevented, as was Bax and PARP activation. Bortezomib delayed tumor growth, and HNG did not interfere with the anticancer effect when studied in human tumor xenografts or cell lines. Conclusions HNG prevents bortezomib-induced bone growth impairment without interfering with bortezomib's desired anti- cancer effects. [ABSTRACT FROM AUTHOR]

Objectives/Aim: To investigate whether nasal aerosol clonidine can reduce the onset time of preoperative sedation. Background: Premedication is common in the pediatric population, but the optimal agent and administration route is still a matter of debate. Clonidine has many beneficial effects in the perioperative period. Clonidine nasal drops produce a similar sedative effect as after oral administration but do not reduce the onset time. Nasal aerosol administration of drugs is generally more effective than drops and an option to decrease the onset time of clonidine. Methods: Pediatric ASA status 1 and 2 patients were randomized to receive placebo (P), clonidine 3-4 μg kg−1 (C4), or clonidine 7-8 μg kg−1 (C7) as a nasal aerosol. Acceptance of administration, pre- and postoperative sedation, and adverse events were assessed. Results: A total of 60 patients were enrolled with a median age of 3.5 years (range 0.7-6.9) and median weight of 14.8 kg (range 10-25). In the C7 group, 55% of the children were found adequately sedated at 30 min as compared to 32% in the C4 group ( P = 0.1202). At 45 min, adequate sedation was seen in 65% of the patients in both C4 and C7 groups, which were both found to be significantly higher compared with the placebo control group (14%) ( P-values = 0.0027 and 0.0013, respectively). The postoperative sedation profile did not differ between the three study groups. Conclusions: Clonidine administered as nasal aerosol (3-8 μg kg−1) was not found to achieve adequate preoperative sedation within 30 min of administration. Despite its sedative properties, no prolongation of postoperative sedation was noted compared with placebo. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was to validate the Mosteller formula for the estimation of body surface area (BSA) in various childhood ages. Many physiological processes including drug metabolism correlate with values for BSA. In addition, dosing of many drugs, especially drugs with low therapeutic index, for example, anti-neoplastics, are based on estimated values of BSA. Methods: Published data from measured BSA in 268 children and infants (median age: 8 month; range: 0-18 years) were compared with BSA values estimated by the Mosteller formula. Correlation between estimated and measured BSA values was performed by the Spearman rank correlation. Bias and precision were evaluated as outlined by Sheiner and Beal. Measured and estimated BSA values were compared by the Eksborg's plot. Results: Measured values of BSA and BSA values estimated by the Mosteller formula were closely correlated (rs = 0.973; p < 0.0001). The formula of Mosteller had with a precision of 9.38% and underestimated BSA by 4.06%. The quotients Estimated/Measured BSA were within the range 0.9-1.1 in 71.3% of the observations, but deviation up to 35% occurred. Conclusion: The Mosteller formula underestimates BSA in the paediatric population and must be used with precautions because of low precision, most pronounced in neonates and infants. [ABSTRACT FROM AUTHOR]

Purpose: Thiosulfate may reduce cisplatin-induced ototoxicity, most likely by relieving oxidative stress and by forming inactive platinum complexes. This study aimed to determine the concentration and protective effect of thiosulfate in the cochlea after application of a thiosulfate-containing high viscosity formulation of sodium hyaluronan (HYA gel) to the middle ear prior to i.v. injection of cisplatin in a guinea pig model. Methods: The release of thiosulfate (0.1 M) from HYA gel (0.5% w/w) was explored in vitro. Thiosulfate in the scala tympani perilymph of the cochlea 1 and 3 h after application of thiosulfate in HYA gel to the middle ear was quantified with HPLC and fluorescence detection. Thiosulfate in blood and CSF was also explored. The potential otoprotective effect was evaluated by hair cell count after treatment with thiosulfate in HYA gel applied to the middle ear 3 h prior to cisplatin injection (8 mg/kg b.w.). Results: HYA did not impede the release of thiosulfate. Middle ear administration of thiosulfate in HYA gel gave high concentrations in the scala tympani perilymph while maintaining low levels in blood, and it protected against cisplatin-induced hair cell loss. Conclusion: HYA gel is an effective vehicle for administration of thiosulfate to the middle ear. Local application of a thiosulfate-containing HYA gel reduces the ototoxicity of cisplatin most likely without compromising its antineoplastic effect. This provides a minimally invasive protective treatment that can easily be repeated if necessary. [ABSTRACT FROM AUTHOR]

Oral clonidine is used as premedication in children. The bioavailability of clonidine given orally in adults is 75-100% but is unknown in children. Children (3-10 years) undergoing adenotonsillectomy were administered oral clonidine 4 mcg·kg mixed with apple fruit drink as premedication. Intravenous plasma was assayed for clonidine concentration at 5, 15, 30, 45 min and 1, 2, 4, 6, 12, 18 h after administration. Clonidine plasma concentrations were determined by liquid chromatography-mass spectroscopy, and pharmacokinetic parameters were calculated using nonlinear effects mixed-effects models. Current data were pooled with published time-concentration profiles from children ( n = 49) administered intravenous clonidine to determine oral bioavailability. There were eight children studied (age 3-10 years, weight 10.5-36 kg). A two-compartment model with first-order absorption and elimination was used to describe time-concentration profiles. Population parameter estimates (CV%; 95% CI), standardized to a 70-kg person, were absorption half-life (Tabs), 0.45 (85.1; 0.221-0.884) h, absorption lag time (Tlag), 0.148 (91.2; 0.002-0.316) h, Clearance (CL) 17.9 (30.3; 16-20.3) l·h per 70 kg, between compartment clearance (Q) 121 (44.3; 80.1-165) l·h per 70 kg, central volume (V1) 81.2 (71.5; 60.7-105) l·70 kg, peripheral volume of distribution (V2) 113 (33.9; 91-131) l·70 kg. The oral bioavailability was 55.4% (CV 6.4%; 95% CI 0.469, 0.654). Clonidine administered with an apple fruit drink displays a variable and relatively slow absorption after oral administration ( T 1.04 h, C 0.77 mcg·l). The oral bioavailability was 55.4%, which is less than reported in adults. Consequently, higher oral doses of clonidine (per kg) are required when this formulation is used to achieve concentrations similar to those reported in adults. [ABSTRACT FROM AUTHOR]

Abstract: A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for determination of the new anticancer agent picropodophyllin (AXL1717) and its isomer podophyllotoxin levels in human serum has been developed. Monitoring of hexylamine adducts rather than proton adducts was used to optimize sensitivity. The chromatography system was an Acquity BEH C18, 2.1mm×50mm 1.7μm column with gradient elution (mobile phase A: 2.5mM hexylamine and 5mM formic acid in Milli-Q water and mobile phase B: methanol). The retention times were 1.4min for picropodophyllin, 1.5min for podophyllotoxin and 1.9min for internal standard deoxypodophyllotoxin. The isomers were base-line separated. The analytes were detected after electrospray ionization in positive mode with selected reaction monitoring (SRM) with ion transitions m/z 516→102 for picropodophyllin and podophyllotoxin and m/z 500→102 for internal standard. The sample preparation was protein precipitation with acetonitrile (1:3) containing internal standard followed by dilution of the supernatant with mobile phase A (1:1). The limit of quantification (LOQ) was 0.01μmol/L for picropodophyllin and podophyllotoxin. The limit of detection (LOD) at 3 times the signal to noise (S/N) was estimated below 0.001μmol/L for picropodophyllin and podophyllotoxin. The quantification range of the method was between 0.01μmol/L and 5μmol/L for both isomers. The accuracy was within ±15% of the theoretical value for both picropodophyllin and podophyllotoxin and inter-assay precision did not exceed ±15%, except for the 0.016μmol/L level of podophyllotoxin, which was 18%. The selectivity of the method was verified by analysis of two different product ions for each analyte and by analysis for interference of seven different batches of blank human serum. The combined recovery and matrix effects were about 83% for picropodophyllin and podophyllotoxin. The new LC–MS/MS method showed sufficient sensitivity and selectivity for determination of picropodophyllin and its isomer podophyllotoxin levels in human serum from subjects receiving therapeutic doses of AXL1717. [Copyright &y& Elsevier]

The aim of this prospective, age-stratified, observational study was to determine the cranial extent of spread of a large volume (1.5 ml·kg, ropivacaine 0.2%), single-shot caudal epidural injection using real-time ultrasonography. Fifty ASA I-III children were included in the study, stratified in three age groups; neonates, infants (1-12 months), and toddlers (1-4 years). The caudal blocks were performed during ultrasonographic observation of the spread of local anesthetic (LA) in the epidural space. A significant inverse relationship was found between age, weight, and height, and the maximal cranial level reached by 1.5 ml·kg of LA. In neonates, 93% of the blocks reached a cranial level of ≥Th12 vs 73% and 25% in infants and toddlers, respectively. Based on our data, a predictive equation of segmental spread was generated: Dose (ml/spinal segment) = 0.1539·(BW in kg)-0.0937. This study found an inverse relationship between age, weight, and height and the number of segments covered by a caudal injection of 1.5 ml·kg of ropivacaine 0.2% in children 0-4 years of age. However, the cranial spread of local anesthetics within the spinal canal as assessed by immediate ultrasound visualization was found to be in poor agreement with previously published predictive equations that are based on actual cutaneous dermatomal testing. [ABSTRACT FROM AUTHOR]