Outcomes of pediatric patients with therapy-related myeloid neoplasms

Long-term outcomes after allogeneic hematopoietic cell transplantation (HCT) for therapy-related myeloid neoplasms (tMNs) are dismal. There are few multicenter studies defining prognostic factors in pediatric patients with tMNs. We have accumulated the largest cohort of pediatric patients who have undergone HCT for a tMN to perform a multivariate analysis defining factors predictive of long-term survival. Sixty-eight percent of the 401 patients underwent HCT using a myeloablative conditioning (MAC) regimen, but there were no statistically significant differences in the overall survival (OS), event-free survival (EFS), or cumulative incidence of relapse and non-relapse mortality based on the conditioning intensity. Among the recipients of MAC regimens, 38.4% of deaths were from treatment-related causes, especially acute graft versus host disease (GVHD) and end-organ failure, as compared to only 20.9% of deaths in the reduced-intensity conditioning (RIC) cohort. Exposure to total body irradiation (TBI) during conditioning and experiencing grade III/IV acute GVHD was associated with worse OS. In addition, a diagnosis of therapy-related myelodysplastic syndrome and having a structurally complex karyotype at tMN diagnosis were associated with worse EFS. Reduced-toxicity (but not reduced-intensity) regimens might help to decrease relapse while limiting mortality associated with TBI-based HCT conditioning in pediatric patients with tMNs

A local glucose-and oxygen concentration-based insulin secretion model for pancreatic islets

<p>Abstract</p> <p>Background</p> <p>Because insulin is the main regulator of glucose homeostasis, quantitative models describing the dynamics of glucose-induced insulin secretion are of obvious interest. Here, a computational model is introduced that focuses not on organism-level concentrations, but on the quantitative modeling of local, cellular-level glucose-insulin dynamics by incorporating the detailed spatial distribution of the concentrations of interest within isolated avascular pancreatic islets.</p> <p>Methods</p> <p>All nutrient consumption and hormone release rates were assumed to follow Hill-type sigmoid dependences on local concentrations. Insulin secretion rates depend on both the glucose concentration and its time-gradient, resulting in second-and first-phase responses, respectively. Since hypoxia may also be an important limiting factor in avascular islets, oxygen and cell viability considerations were also built in by incorporating and extending our previous islet cell oxygen consumption model. A finite element method (FEM) framework is used to combine reactive rates with mass transport by convection and diffusion as well as fluid-mechanics.</p> <p>Results</p> <p>The model was calibrated using experimental results from dynamic glucose-stimulated insulin release (GSIR) perifusion studies with isolated islets. Further optimization is still needed, but calculated insulin responses to stepwise increments in the incoming glucose concentration are in good agreement with existing experimental insulin release data characterizing glucose and oxygen dependence. The model makes possible the detailed description of the intraislet spatial distributions of insulin, glucose, and oxygen levels. In agreement with recent observations, modeling also suggests that smaller islets perform better when transplanted and/or encapsulated.</p> <p>Conclusions</p> <p>An insulin secretion model was implemented by coupling local consumption and release rates to calculations of the spatial distributions of all species of interest. The resulting glucose-insulin control system fits in the general framework of a sigmoid proportional-integral-derivative controller, a generalized PID controller, more suitable for biological systems, which are always nonlinear due to the maximum response being limited. Because of the general framework of the implementation, simulations can be carried out for arbitrary geometries including cultured, perifused, transplanted, and encapsulated islets.</p

Influence of health insurance status on paediatric non-Hodgkin's lymphoma treatment in Kenya

Objective: Non-Hodgkin's lymphoma (NHL) is the most common childhood malignancy in sub-Saharan Africa. Survival rates for NHL are higher than 80% in high-income countries.This study explores treatment outcomes of children with NHL in Kenya, a sub-Saharan low-income country, and the association between health insurance status at diagnosis and treatment outcomes. Design: This was a retrospective medical records study. All children diagnosed with NHL in 2010, 2011 and 2012 were included. Data on treatment outcomes and health insurance status at diagnosis were collected. Results: Of all 63 patients with NHL, 35% abandoned treatment, 22% had progressive or relapsed disease, 14% died and 29% had event-free survival. Most patients (73%) had no health insurance at diagnosis. Treatment outcomes in children with or without health insurance at diagnosis differed significantly (p=0.005). The most likely treatment outcome in children with health insurance at diagnosis was event-free survival (53%), whereas in children without health insurance at diagnosis it was abandonment of treatment (44%). Crude HR for treatment failure was 3.1 (95% CI 1.41 to 6.60, p=0.005) for uninsured versus insured children. The event-free survival estimate was significantly higher in children with health insurance at diagnosis than in patients without health insurance at diagnosis (p=0.003). Stage of disease at diagnosis was identified as a confounder of this association (adjusted HR=2.4, 95% CI 0.95 to 6.12, p=0.063). Conclusions: Survival of children with NHL in Kenya is much lower compared with high-income countries. Abandonment of treatment is the most common cause of treatment failure. Health insurance at diagnosis was associated with better treatment outcomes and survival