Pathogenesis of hepatic steatosis in the parenterally fed rat.

Hepatic steatosis frequently complicates total parenteral nutrition (TPN). Some of the mechanisms responsible were examined in rats receiving calories as dextrose (CHO-TPN) or dextrose plus lipid emulsion (Lipid-TPN). Hepatic triglyceride content increased approximately threefold after CHO-TPN and twofold after Lipid-TPN (P less than 0.02). Hepatic triglyceride fatty acid composition reflected endogenous synthesis. Hepatic acetyl-Coenzyme A carboxylase specific activity increased fourfold after CHO-TPN and twofold after Lipid-TPN, and it correlated positively with hepatic lipid content (r = 0.82). The activities of the microsomal enzymes of complex lipid synthesis were unchanged in the TPN groups. Both TPN regimens suppressed hepatic triglyceride secretion, measured by the rise in plasma triglyceride and the incorporation of [14C]palmitic acid into plasma triglyceride after intravenous Triton. Hepatic triglyceride secretion correlated negatively with total hepatic lipid content (r = -0.89). CHO-TPN increased the uptake of a radiolabeled triglyceride emulsion and increased hepatic lipase activity, whereas Lipid-TPN decreased both. Both adipose and cardiac lipase were higher for Lipid-TPN animals than for CHO-TPN or control animals. Hepatic 14C-triglyceride content was increased in both TPN groups as compared with controls after the injection of 1-[14C]-palmitic acid. This increment was proportional to the decreased hepatic secretion. Triglyceride fatty acid oxidation was significantly suppressed by CHO-TPN, less so by Lipid-TPN. Free fatty acid oxidation was suppressed only by CHO-TPN. The results suggest that the steatosis induced by TPN in rats was due to enhanced hepatic synthesis of fatty acid and reduced triglyceride secretion. Reduced hepatic triglyceride uptake, enhanced fatty acid oxidation, and enhanced peripheral tissue plasma triglyceride lipolysis when CHO-TPN is supplemented with lipid may modulate the accumulation of hepatic triglyceride and, along with reduced synthesis of fatty acid, lead to a lower hepatic triglyceride content.     

Effects of catecholamines and adrenergic-blocking agents on plasma and urinary cyclic nucleotides in man

Studies were performed in healthy volunteers to determine the effects of catecholamines and adrenergic-blocking agents on plasma and urinary levels of adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP).Plasma cyclic AMP rose in response to infusions of the beta-adrenergic agent, isoproterenol, or in response to infusions of either epinephrine or norepinephrine alone or in combination with the alpha-adrenergic-blocking agent, phentolamine. Although urinary cyclic AMP also rose, the percentage increase was less than that observed in the plasma. These treatments caused no increase in plasma cyclic GMP.Plasma cyclic GMP rose in response to infusions of alpha-adrenergic agents, viz., epinephrine or norepinephrine infused together with the beta-blocking agent, propranolol. These treatments caused no increase in plasma cyclic AMP.These observations are consistent with the current concept that the actions of beta-adrenergic agents are mediated by increases in cyclic AMP formation in target tissues. Such a mediating role has not been established for cyclic GMP, but the data suggest the possibility that cyclic GMP metabolism is responsive either to alpha-adrenergic stimulation or to parasympathetic stimulation which occurs as a reflexive consequence of the pressor effect of alpha-adrenergic agents.     

Population pharmacokinetics of rifapentine and its primary desacetyl metabolite in South African tuberculosis patients

This study was designed to describe the population pharmacokinetics of rifapentine (RFP) and 25-desacetyl RFP in a South African pulmonary tuberculosis patient population. Special reference was made to studying the influence of previous exposure to rifampin (RIF) and the variability in pharmacokinetic parameters between patients and between occasions and the influence of different covariates. Patients were included in the study if they had been receiving first-line antimycobacterial therapy (rifampin, isoniazid, pyrazinamide, and ethambutol) for not less than 4 weeks and not more than 6 weeks and were divided into three RFP dosage groups based on weight: 600 mg, <45 kg; 750 mg, 46 to 55 kg; and 900 mg, >55 kg. Participants received a single oral dose of RFP together with concomitant antimycobacterial agents, excluding RIF, on study days 1 and 5 after they ingested a soup-based meal. The RFP and 25-desacetyl RFP concentration-time data were analyzed by nonlinear mixed-effect modeling using NONMEM. The pharmacokinetics of the parent drug were modeled separately, and the individual pharmacokinetic parameters were used as inputs for the 25-desacetyl RFP pharmacokinetic model. A one-compartment disposition model was found to best describe the data for both the parent and the metabolite, and the metabolite was assumed to be formed only from the central compartment of the parent drug. Prior treatment with RIF did not alter the pharmacokinetics of RFP but appeared to increase the excretion of 25-desacetyl RFP in a nonlinear fashion. The RFP oral clearance and volume of distribution were found to increase by 0.049 liter/h and 0.691 liter, respectively, with a 1-kg increase from the median weight of 50 kg. The oral clearance of 25-desacetyl RFP was found to be 35% lower in female patients. The model developed here describes the population pharmacokinetics of RFP and its primary metabolite in tuberculosis patients and includes the effects of prior administration with RIF and covariate factors.     

The Interprofessional Rural Program of British Columbia (IRPbc)

The Interprofessional Rural Program of British Columbia IRPbc was established in 2003 as an important first step for the Province of British Columbia, Canada, in creating a collaborative interprofessional education initiative that engages numerous communities, health authorities and post-secondary institutions in working toward a common goal. Designed to foster interprofessional education and promote rural recruitment of health professionals, the program places teams of students from a number of health professional programs into rural and remote British Columbia communities. In addition to meeting their discipline specific learning objectives, the student teams are provided with the opportunity to experience the challenges of rural life and practice and advance their interprofessional competence. To date, 62 students have participated in the program from nursing, social work, medicine, physical therapy, occupational therapy, pharmaceutical sciences, speech language pathology, audiology, laboratory technology, and counseling psychology. While not without numerous struggles and challenges, IRPbc has been successful in meeting the program mandate. It has also had a number of positive outcomes not anticipated at the time the program was established.     

Weight Gain and Its Correlates Among Forensic Inpatients

Objective:

We investigated changes in weight, body mass index (BMI), and other indices of the metabolic syndrome in forensic inpatients. Weight gain associated with newer antipsychotics (APs) is well established in the general psychiatric population.

Methods:

We examined the medical records of 291 men admitted to a forensic hospital at admission and again at discharge or 365 days later if still in hospital. We also recorded diagnosis and smoker status on admission and quantified psychotropic treatment and adherence, physical activity, and daytime occupation during the hospitalization.

Results:

On admission, 33% were obese and 22% of the 106 patients for whom sufficient data were available met criteria for metabolic syndrome. Among patients staying at least 30 days, 60% were weighed again before discharge but repeated blood pressure and waist circumference measures were uncommon, even among those at greatest risk. The 122 forensic inpatients with sufficient information gained an average of 12% of their body weight and 40% increased by at least 1 BMI category, gaining an average of 3.67 kg per month. Weight gain was associated with duration of time and was not attributable to being underweight on admission, diagnosis of schizophrenia, atypical AP treatment, medication adherence, or having been a smoker.

Conclusions:

Patients gained weight during forensic hospitalization independent of medication use. We recommend further research using consistent measurement and wider sampling of both metabolic syndrome indicators and its individual and systemic causes in forensic populations.     

In vitro screen of a small molecule inhibitor drug library identifies multiple compounds that synergize with oncolytic myxoma virus against human brain tumor-initiating cells

Background

Brain tumor-initiating cells (BTICs) are stem-like cells hypothesized to form a disease reservoir that mediates tumor recurrence in high-grade gliomas. Oncolytic virotherapy uses replication-competent viruses to target and kill malignant cells and has been evaluated in clinic for glioma therapy with limited results. Myxoma virus (MyxV) is a safe and highly effective oncolytic virus (OV) in conventional glioma models but, as seen with other OVs, is only modestly effective for patient-derived BTICs. The objective of this study was to determine whether MyxV treatment against human BTICs could be improved by combining chemotherapeutics and virotherapy.

Methods

A 73-compound library of drug candidates in clinical use or preclinical development was screened to identify compounds that sensitize human BTICs to MyxV treatment in vitro, and synergy was evaluated mathematically in lead compounds using Chou-Talalay analyses. The effects of combination therapy on viral gene expression and viral replication were also assessed.

Results

Eleven compounds that enhance MyxV efficacy were identified, and 6 were shown to synergize with the virus using Chou-Talalay analyses. Four of the synergistic compounds were shown to significantly increase viral gene expression, indicating a potential mechanism for synergy. Three highly synergistic compounds (axitinib, a VEGFR inhibitor; rofecoxib, a cyclooxygenase-2 inhibitor; and pemetrexed, a folate anti-metabolite) belong to classes of compounds that have not been previously shown to synergize with oncolytic viruses in vitro.

Conclusions

This study has identified multiple novel drug candidates that synergistically improve MyxV efficacy in a preclinical BTIC glioma model.