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BSTRACT The effect of exponential decay pulsed electric fields on peach (var. Miraflores) polyphenoloxidase (PPO) was evaluated. Electric field intensities ranged from 2.18 to 24.30 kV/cm. Pulses of 0.02 and 0.08 ms width were applied in mono- and bipolar mode. A 70% maximum reduction in enzymatic activity was achieved after 5 ms using 0.02 ms width pulses in bipolar mode at 24.30 kV/cm. Peach PPO activity decreased following an exponential decay kinetic model. Rate constants ranged from 9.0 to 138 μS-1 in monopolar mode, and from 8.7 to 235 μS-1 in bipolar mode. An exponential decay model may describe the relationship between residual PPO and input electric energy. [ABSTRACT FROM AUTHOR]

Asparaginase (ASP) is an essential component for the acute lymphoblastic leukemia (ALL) treatment, but toxicities, such as allergy, frequently limit its use. Although the potentially lower PEG-ASP formulation immunogenicity, few studies with conflicting results have compared the allergy incidence between Escherichia coli-ASP and PEG-ASP in the same protocol. We aimed at comparing the allergy incidence in children receiving native E. coli-ASP versus PEG-ASP within the same clinical protocol (Spanish Society of Pediatric Hematology and Oncology ALL-SEHOP-PETHEMA 2013). One hundred and twenty-six children (1-19 years) diagnosed with ALL from 2013 to 2020 were included. Patients in group 1 received a sequential scheme of native E. coli-ASP 10,000 IU/m 2 intramuscularly (IM) followed by PEG-ASP 1000 IU/m 2 IM. Patients in group 2 received PEG-ASP 1000 IU/m 2 IM upfront. Clinical allergy incidence was compared between both groups. Serum ASP activity (SAA) was measured in a subgroup of patients, and silent inactivation was recorded. The cumulative incidence of clinical allergy was significantly higher in group 1 (native followed by PEG-ASP) than in group 2 (PEG-ASP upfront), 24.7% versus 4.1% (p = 0.0085). Adequate ASP activity was achieved with PEG-ASP 1000 IU/m 2 dose in most patients (median SAA 412.5 and 453.0 IU/L at days 7 and 14). The incidence of silent inactivation in PEG-ASP upfront patients was very low. PEG-ASP-used upfront was associated with a lower incidence of clinical allergy than that observed in the sequential use of native E. coli-ASP followed by PEG-ASP. PEG-ASP at 1000 IU/m 2 was effective in achieving enough ASP activity in most patients., (© 2021 John Wiley & Sons Ltd.)

Aim: To evaluate the incidence and outcome of secondary immune thrombocytopenia (ITP) in a large cohort of paediatric Spanish patients., Methods: A retrospective observational study was conducted in two paediatric University hospitals in Spain between 2009 and 2019, which included children from 4 months to 18 years old diagnosed with ITP. Data were recorded from clinical charts: gender, age at diagnosis, coexisting condition and associated characteristics, outcome and treatment., Results: Secondary ITP was diagnosed in 87 out of 442 patients (19.6%). Post-immunisation ITP was seen in younger children. The onset of secondary ITP to autoimmune diseases (AD) and immunodeficiencies (ID) was at an older age and had more tendency to be insidious, and platelet level was higher than primary ITP. Mean time from ITP onset to AD diseases or ID diagnosis was 1.2 and 2.6 years, respectively. Whereas the cumulative incidence of remission was significantly higher in post-immunisation and post-viral infection (compared with primary ITP patients), it was worse in AD and ID patients., Conclusions: Identification of secondary ITP is important as it predicts outcome. Most of them are diagnosed at ITP onset, but AD diseases and ID should be ruled out periodically as they are usually identified later., (©2021 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

Histone deacetylase inhibitors (HDACi) had emerged as promising drugs in leukaemia, but their toxicity due to lack of specificity limited their use. Therefore, there is a need to elucidate the role of HDACs in specific settings. The study of HDAC expression in childhood leukaemia could help to choose more specific HDACi for selected candidates in a personalized approach. We analysed HDAC1-11, SIRT1, SIRT7, MEF2C and MEF2D mRNA expression in 211 paediatric patients diagnosed with acute leukaemia. There was a global overexpression of HDACs, while specific HDACs correlated with clinical and biological features, and some even predicted outcome. Thus, some HDAC and MEF2C profiles probably reflected the lineage and the maturation of the blasts and some profiles identified specific oncogenic pathways active in the leukaemic cells. Specifically, we identified a distinctive signature for patients with KMT2A (MLL) rearrangement, with high HDAC9 and MEF2D expression, regardless of age, KMT2A partner and lineage. Moreover, we observed an adverse prognostic value of HDAC9 overexpression, regardless of KMT2A rearrangement. Our results provide useful knowledge on the complex picture of HDAC expression in childhood leukaemia and support the directed use of specific HDACi to selected paediatric patients with acute leukaemia., (© 2018 British Society for Haematology and John Wiley & Sons Ltd.)