Predictions of tissue concentrations of myclobutanil, oxyfluorfen, and pronamide in rat and human after oral exposures via GastroPlusTM physiologically based pharmacokinetic modelling

Heritage agrochemicals like myclobutanil, oxyfluorfen, and pronamide, are extensively used in agriculture, with well-established studies on their animal toxicity. Yet, human toxicity assessment relies on conventional human risk assessment approaches including the utilization of animal-based ADME (Absorption, Distribution, Metabolism, and Excretion) data. In recent years, Physiologically Based Pharmacokinetic (PBPK) modelling approaches have played an increasing role in human risk assessment of many chemicals including agrochemicals. This study addresses the absence of PBPK-type data for myclobutanil, oxyfluorfen, and pronamide by generating in vitro data for key input PBPK parameters (Caco-2 permeability, rat plasma binding, rat blood to plasma ratio, and rat liver microsomal half-life), followed by generation of PBPK models for these three chemicals via the GastroPlusTM software. Incorporating these experimental input parameters into PBPK models, the prediction accuracy of plasma AUC (area under curve) was significantly improved. Validation against rat oral administration data demonstrated substantial enhancement. Steady-state plasma concentrations (Css) of pronamide aligned well with published data using measured PBPK parameters. Following validation, parent-based tissue concentrations for these agrochemicals were predicted in humans and rats after single or 30-day repeat exposure of 10 mg/kg/day. These predicted concentrations contribute valuable information for future human toxicity risk assessments of these agrochemicals.

Effect of portal glucose sensing on incretin hormone secretion in a canine model

It is unknown whether activation of hepato-portal vein (PV) glucose sensors plays a role in incretin hormone amplification of oral glucose-stimulated insulin secretion (GSIS). In previous studies, PV glucose infusion increased GSIS through unknown mechanisms, perhaps neural stimulation of pancreatic β-cells and/or stimulation of gut incretin hormone release. Thus, there could be a difference in the incretin effect when comparing GSIS with portal rather than leg vein (LV) glucose infusion. Plasma insulin and incretin hormones were studied in six overnight-fasted dogs. An oral glucose tolerance test (OGTT) was administered, and then 1 and 2 wk later the arterial plasma glucose profile from the OGTT was mimicked by infusing glucose into either the PV or a LV. The arterial glucose levels were nearly identical between groups (AUCs within 1% of each other). Oral glucose administration increased arterial GLP-1 and GIP levels by more than sixfold, whereas they were not elevated by PV or LV glucose infusion. Oral glucose delivery was associated with only a small incretin effect (arterial insulin and C-peptide were 21 ± 23 and 24 ± 17% greater, respectively, during the 1st hour with oral compared with PV glucose and 14 ± 37 and 13 ± 35% greater, respectively, in oral versus LV; PV versus LV responses were not significantly different from each other). Thus, following an OGTT incretin hormone release did not depend on activation of PV glucose sensors, and the insulin response was not greater with PV compared with LV glucose infusion in the dog. The small incretin effect points to species peculiarities, which is perhaps related to diet.

IGFBP2 potentiates nuclear EGFR-STAT3 signaling

Insulin-like growth factor binding protein 2 (IGFBP2) is a pleiotropic oncogenic protein that has both extracellular and intracellular functions. Despite a clear causal role in cancer development, the tumor-promoting mechanisms of IGFBP2 are poorly understood. The contributions of intracellular IGFBP2 to tumor development and progression are also unclear. Here we present evidence that both exogenous IGFBP2 treatment and cellular IGFBP2 overexpression lead to aberrant activation of EGFR, which subsequently activates STAT3 signaling. Furthermore, we demonstrate that IGFBP2 augments the nuclear accumulation of EGFR to potentiate STAT3 transactivation activities, via activation of the nuclear EGFR signaling pathway. Nuclear IGFBP2 directly influences the invasive and migratory capacities of human glioblastoma cells, providing a direct link between intracellular (and particularly nuclear) IGFBP2 and cancer hallmarks. These activities are also consistent with the strong association between IGFBP2 and STAT3-activated genes derived from the TCGA database for human glioma. A high level of all 3 proteins (IGFBP2, EGFR and STAT3) was strongly correlated with poorer survival in an independent patient dataset. These results identify a novel tumor-promoting function for IGFBP2 of activating EGFR/STAT3 signaling and facilitating EGFR accumulation in the nucleus, thereby deregulating EGFR signaling by 2 distinct mechanisms. As targeting EGFR in glioma has been relatively unsuccessful, this study suggests that IGFBP2 may be a novel therapeutic target.

Investing your money: the long and the short of it

Because of rapid changes in the stock market and the health care environment, boards must rethink their short- and long-term investment strategies. Experts offer practical advice about how to restructure your investments for the new economy.

High standards: ISO 9000 comes to health care

ISO 9000, an international quality system, is catching on in health care. Providers see it as a much less expensive alternative or as a complement to the JCAHO. And because ISO has been used for years in manufacturing, it has one big advantage over JCAHO: employers know it and trust it.

Outcome analysis of a pharmacist-managed anticoagulation service

The primary objective of this study was to determine if a pharmacist-managed anticoagulation monitoring service (AMS) improved the outcomes of patients receiving warfarin in a family practice setting and was cost effective in treating and preventing thromboembolic disorders. A retrospective chart review was performed on all patients at the University of Florida's Family Practice Residency Program who received warfarin pharmacotherapy between October 1, 1988, and December 15, 1993. The outcomes of patients followed by AMS were compared with those of a control group consisting of patients receiving warfarin but followed only by their physician. Outcomes were evaluated based on the number of thromboembolic and hemorrhagic events, as well as unplanned clinic visits, emergency room visits, and hospital admissions. Cost of hospital admissions, emergency room visits, and participation in the AMS were analyzed. During 28 person-years of treatment, control subjects sustained 12 thromboembolic events (2 pulmonary embolisms, 1 cerebrovascular accident, and 9 deep venous thromboses) and 2 minor and 5 major hemorrhagic events. The study group reported two minor hemorrhagic events during a total of 60 person-years. The control group was 20 times more likely than the study group to experience any event (rate ratio 20, 95% CI 5-87). In addition, hospitalization and emergency room charges indicated an actual cost of $119,074.95 for the control group's events. The cost to this group for 28 person-years of participation in the AMS would have been $5040.00. A potential cost avoidance of $4072.68 per person-year of follow-up may have been possible if these patients had been followed by the AMS. A pharmacist-managed AMS in a family practice setting can result in improved outcomes for patients receiving warfarin and is cost effective.

A psychiatric residential centre for children and adolescents: a pilot study of its patients' characteristics and improvement while resident

This paper describes the history and philosophy of a unique residential treatment unit in Ireland which caters for emotionally and behaviourally disturbed children and adolescents. A pilot study was undertaken to help identify the type of patient seen and who benefited from the treatment.

Running groups for parents with schizophrenic adolescents: initial experiences and plans for the future

Six-session educational and support groups were held for two sets of parents (32 in all) who had an adolescent schizophrenic child. Results indicate no significant increases in knowledge about the disorder following the group (probably due to the relatively high scores obtained at the outset) but gains seem to have been made in ability to handle the teenage patient at home. All parents commented on how they had benefited from the supportive aspect of the group. Future developments of these groups are discussed.

Sucrose taste thresholds: age-related differences

Sucrose taste detection thresholds were measured in 71 adults aged 20 to 88 years. A forced-choice, tracking procedure was used to eliminate subject response bias and rinses were included between all stimuli. A significant age-related decrease in sensitivity was observed. However, the loss of sensitivity was not great and elderly people had highly variable thresholds. A similar study on salt taste acuity has been reported from this laboratory demonstrating a small, but statistically significant threshold increment with age. The observation that age-related differences in taste sensitivity are not large is consistent with biological information that taste bud cells are continuously replaced in adult mammals.