The acute effects of daily nicotine intake on heart rate--a toxicokinetic and toxicodynamic modelling study.

Abstract Joint physiologically-based toxicokinetic and toxicodynamic (PBTK/TD) modelling was applied to simulate concentration–time profiles of nicotine, a well-known stimulant, in the human body following single and repeated dosing. Both kinetic and dynamic models were first calibrated by using in vivo literature data for the Caucasian population. The models were then used to estimate the blood and liver concentrations of nicotine in terms of the Area Under Curve (AUC) and the peak concentration (Cmax) for selected exposure scenarios based on inhalation (cigarette smoking), oral intake (nicotine lozenges) and dermal absorption (nicotine patches). The model simulations indicated that whereas frequent cigarette smoking gives rise to high AUC and Cmax in blood, the use of nicotine-rich dermal patches leads to high AUC and Cmax in the liver. Venous blood concentrations were used to estimate one of the most common acute effects, mean heart rate, both at rest and during exercise. These estimations showed that cigarette smoking causes a high peak heart rate, whereas dermal absorption causes a high mean heart rate over 48 h. This study illustrates the potential of using PBTK/TD modelling in the safety assessment of nicotine-containing products

In vitro-to-in vivo correlation of the skin penetration, liver clearance and hepatotoxicity of caffeine

Abstract This work illustrates the use of Physiologically-Based Toxicokinetic (PBTK) modelling for the healthy Caucasian population in in vitro -to- in vivo correlation of kinetic measures of caffeine skin penetration and liver clearance (based on literature experiments), as well as dose metrics of caffeine-induced measured HepaRG toxicity. We applied a simple correlation factor to quantify the in vitro and in vivo differences in the amount of caffeine permeated through the skin and concentration-time profiles of caffeine in the liver. We developed a multi-scale computational approach by linking the PBTK model with a Virtual Cell-Based Assay to relate an external oral and dermal dose with the measured in vitro HepaRG cell viability. The results revealed higher in vivo skin permeation profiles than those determined in vitro using identical exposure conditions. Liver clearance of caffeine derived from in vitro metabolism rates was found to be much slower than the optimised in vivo clearance with respect to caffeine plasma concentrations. Finally, HepaRG cell viability was shown to remain almost unchanged for external caffeine doses of 5–400 mg for both oral and dermal absorption routes. We modelled single exposure to caffeine only

Methods for reliability and uncertainty assessment and for applicability evaluations of classification- and regression-based QSARs

This article provides an overview of methods for reliability assessment of quantitative structure–activity relationship (QSAR) models in the context of regulatory acceptance of human health and environmental QSARs. Useful diagnostic tools and data analytical approaches are highlighted and exemplified. Particular emphasis is given to the question of how to define the applicability borders of a QSAR and how to estimate parameter and prediction uncertainty. The article ends with a discussion regarding QSAR acceptability criteria. This discussion contains a list of recommended acceptability criteria, and we give reference values for important QSAR performance statistics. Finally, we emphasize that rigorous and independent validation of QSARs is an essential step toward their regulatory acceptance and implementation. Key words: QSAR acceptability criteria, QSAR applicability domain, QSAR reliability, QSAR uncertainty estimation, QSAR validation

Effect of stem cell source on long-term chimerism and event-free survival in children with primary immunodeficiency disorders after fludarabine and melphalan conditioning regimen

BACKGROUND: Reduced-intensity conditioning (RIC) regimens are increasingly being used in the transplantation of patients with primary immunodeficiency disorders (PIDs), but there are no large studies looking at long-term lineage-specific chimerism. OBJECTIVES: We sought to analyze long-term chimerism and event-free survival in children undergoing transplantation for PIDs using RIC with fludarabine and melphalan (Flu/Melph) and to study the effect of donor type and stem cell source. METHODS: One hundred forty-two children underwent transplantation with RIC by using Flu/Melph and for PIDs by using bone marrow (n = 93) or peripheral blood stem cells (PBSCs; n = 49). Donors were matched unrelated donors (n = 72), mismatched unrelated donors (n = 37), matched sibling donors (n = 14), matched family donors (n = 12), and mismatched family donors (n = 7). RESULTS: Overall survival at a median follow-up of 7.5 years was 78%, irrespective of stem cell source or donor type. When bone marrow was used as the stem cell source, 26% of patients ended up with very low levels of donor chimerism (50% donor chimerism) in all lineages. CONCLUSIONS: On the basis of our experience, we would suggest that PBSCs should be the stem cell source of choice in children with PIDs undergoing transplantation with Flu/Melph RIC from a matched donor source. This is most likely to ensure sustained high-level donor chimerism

Correction of both immunodeficiency and hypoparathyroidism by thymus transplantation in complete DiGeorge Syndrome

Combined immune deficiency due to athymia in patients with complete DiGeorge syndrome can be corrected by allogeneic thymus transplantation. Hypoparathyroidism is a frequent concomitant clinical problem in these patients, which persists after thymus transplantation. Cotransplantation of allogeneic thymus and parental parathyroid tissue has been attempted but does not achieve durable correction of the patients' hypoparathyroidism due to parathyroid graft rejection. Surprisingly, we observed correction of hypoparathyroidism in one patient after thymus transplantation. Immunohistochemical analysis and fluorescence in situ hybridization confirmed the presence of allogeneic parathyroid tissue in the patient's thymus transplant biopsy. Despite a lack of HLA‐matching between thymus donor and recipient, the reconstituted immune system displays tolerance toward the thymus donor. Therefore we expect this patient's hypoparathyroidism to be permanently cured. It is recognised that ectopic parathyroid tissue is not infrequently found in the thymus. If such thymuses could be identified, we propose that their use would offer a compelling approach to achieving lasting correction of both immunodeficiency and hypoparathyroidism

Interpolated wave functions for nonadiabatic simulations with the fixed-node quantum Monte Carlo method

Simulating nonadiabatic effects with many-body wave function approaches is an open field with many challenges. Recent interest has been driven by new algorithmic developments and improved theoretical understanding of properties unique to electron-ion wave functions. Fixed-node diffusion Monte Caro is one technique that has shown promising results for simulating electron-ion systems. In particular, we focus on the CH molecule for which previous results suggested a relatively significant contribution to the energy from nonadiabatic effects. We propose a new wave function ansatz for diatomic systems which involves interpolating the determinant coefficients calculated from configuration interaction methods. We find this to be an improvement beyond previous wave function forms that have been considered. The calculated nonadiabatic contribution to the energy in the CH molecule is reduced compared to our previous results, but still remains the largest among the molecules under consideration.Comment: 7 pages, 3 figure

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals

Rattling Europe’s ordoliberal ‘iron cage’ : the contestation of austerity in Southern Europe

This article explains the popular revolt against austerity in Southern Europe as the outcome of profound politico-economic changes that are shaped by the transformation of the European Union’s (EU’s) macro-economic governance. It comprises three parts. The first part demonstrates how ordoliberalism – the Germanic variant of (neo)liberal economic thinking – was embedded in the EU’s new macro-economic governance, in processes that constitutionalise austerity and remove democratic controls over the economy. The second part examines the impact of austerity-driven reforms on welfare and employment in the aftermath of the sovereign debt crisis. These reforms undermined the social reproduction of Southern Europe’s familistic welfare model by destabilising three key pillars of social protection: employment security for households’ primary earners; small property ownership; and pension adequacy. The third part analyses the emergence of anti-austerity social politics in Southern Europe, both parliamentary and grassroots, and assesses their effectiveness in light of the collapse of public trust in both EU and domestic political institutions. The article concludes with our reflections on the fragility of EU’s integration process under the hegemony of ordoliberalism