Quantitative analysis of dicer substrate oligonucleotides in mouse liver by ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry.

A method using multi-mode solid-phase extraction and ultra-high-performance liquid chromatography (UHPLC)-electrospray mass spectrometry was developed to quantify Dicer-substrate small interfering RNA (DsiRNA) directed against the hypoxanthine phosphoribosyltransferase 1 (HPRT1) gene transcript in mouse liver tissue. The oligonucleotides were separated into sense and antisense strands using a UHPLC C(18) column with mobile phases containing 1,1,1,3,3,3-hexafluoro-2-propanol in both water (mobile phase A) and methanol (mobile phase B) with triethylamine as the ion pairing agent at a column temperature of 65°C. The lower limits of detection for the sense and antisense strands were ~1 ng/mg.

RNAi-based treatment for neovascular age-related macular degeneration by Sirna-027.

Purpose: To assess the safety, tolerability, pharmacokinetics, and dose-limiting toxicity of single intravitreal injection of Sirna-027, a small interfering RNA targeting vascular endothelial growth factor receptor-1, in patients with choroidal neovascularization (CNV) resulting from neovascular age-related macular degeneration (AMD). Secondary objectives included assessment of anatomic changes in retinal thickness, size of CNV, and changes in visual acuity.

Design: Prospective, open-label, single-dose, dose-escalation phase 1 study.

Elucidation of potential bortezomib response markers in mutliple myeloma patients.

Liquid chromatography coupled to mass spectrometry (LC/MS) was used to elucidate early biomarkers of bortezomib response in multiple myeloma patients. The change in serum myeloma M-protein level, maintained for a minimum of 6 weeks, is used as one of the main criteria to evaluate patient clinical response to therapy. The objective of this study was to identify biomarkers using LC/MS in order to predict patient response to bortezomib sooner and more accurately compared to serum M-protein levels.

Effect of orlistat on fecal fat, fecal biliary acids, and colonic cell proliferation in obese subjects.

Background & Aims: Orlistat is a weight management agent that selectively inhibits gastrointestinal lipase activity. Because of orlistat's mode of action, increased fecal fat is presented to the colonic mucosa, and fecal bile acid and free fatty acid composition may be altered during treatment. Our aim was to assess the effect of treatment of obese subjects with orlistat 120 mg 3 times a day for 6 weeks on fecal lipid and bile acid parameters and colonic mucosal cell proliferation.

Phase I study of bortezomib in refractory or relapsed acute leukemias.

Bortezomib (Velcade, formerly PS-341) is proteasome inhibitor with documented antitumor activity in multiple myeloma and other lymphoid malignancies. We performed a Phase I study to investigate the maximum tolerated dose and dose-limiting toxicity of bortezomib in patients with acute leukemias refractory to or relapsing after prior therapy. Fifteen patients were treated with 0.

Pharmacokinetic and pharmacodynamic properties of eptifibatide in subjects with normal or impaired renal function.

Background: Previous studies of the glycoprotein IIb-IIIa inhibitor eptifibatide have included patients with moderate renal impairment (serum creatinine concentrations, 2.0-4.0 mg/dL).

Phase I trial of the proteasome inhibitor PS-341 in patients with refractory hematologic malignancies.

Purpose: To determine the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), and pharmacodynamics (PD) of the proteasome inhibitor bortezomib (previously known as PS-341) in patients with refractory hematologic malignancies.

Patients And Methods: Patients received PS-341 twice weekly for 4 weeks at either 0.40, 1.

Orlistat maintains biliary lipid composition and hepatobiliary function in obese subjects undergoing moderate weight loss.

Objectives: Orlistat, an intestinal lipase inhibitor, has recently been approved by the US Food and Drug Administration for treatment of obesity. The effects of orlistat on hepatobiliary function have not been previously defined. A 4 wk study was performed involving modest weight loss in obese subjects to observe any short-term hepatobiliary responses that occur after initiating treatment with orlistat and a hypocaloric diet.

Comparative evaluation of fecal fat excretion induced by orlistat and chitosan.

Objective: To compare the effects of chitosan and orlistat on fecal fat excretion.

Research Methods And Procedure: A randomized, open-label, two-period sequential design study was used. A total of 12 healthy adult volunteers within 20% of their ideal body weight entered a 7-day run-in diet period before being randomized to orlistat (120 mg) or chitosan (890 mg) three times daily for 7 days.

Short-term orlistat treatment does not affect mineral balance and bone turnover in obese men.

Orlistat is a gastrointestinal lipase inhibitor that is used to reduce dietary fat absorption and to enhance weight loss in subjects consuming a hypocaloric diet. To assess whether orlistat has an effect on the metabolism of six minerals, a 21-d, double-blind, randomized, parallel-group, placebo-controlled mineral balance study was conducted in obese (body mass index > 30 kg/m(2)) men. Subjects consumed a hypocaloric diet with a constant daily mineral content and received daily oral treatment with orlistat (120 mg three times daily) (n = 14) or placebo (three times daily) (n = 14) for 21 d.

Orlistat fails to alter postprandial plasma lipid excursions or plasma lipases in normal-weight male volunteers.

Objectives: After 10 d of orlistat administration (120 mg three times/day), the primary objective was to determine the drug's effect on postprandial plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activities on day 10 after an oral fat-load. The secondary objectives were to determine the effects of orlistat on 12 h postprandial measures of: (1) preheparin HTGL and LPL; and (2) serum triglycerides, very-low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and free fatty acids.

Methods: Twenty-four normal-weight, healthy male volunteers were randomized to either 120 mg orlistat (n=12) or placebo (n=12) three times a day with meals for 10 d.

The interaction of the lipase inhibitor orlistat with ethanol in healthy volunteers.

Objectives: The primary objective was to investigate the possible interference of ethanol on the orlistat effect on inhibition of dietary fat absorption and the possible interference of orlistat on the pharmacokinetics of ethanol. Secondary objectives were to assess the tolerability during concomitant dosing of orlistat and ethanol and to determine the ethanol effect on plasma levels of orlistat.

Methods: This was a double-blind, placebo-controlled, parallel, randomized study performed in 30 (three parallel groups of ten subjects each) healthy normal weight male subjects between the ages of 20 and 30 years.

Mode of action of orlistat.

Gastric and pancreatic lipases are enzymes that play a pivotal role in the digestion of dietary fat. Orlistat, a semisynthetic derivative of lipstatin, is a potent and selective inhibitor of these enzymes, with little or no activity against amylase, trypsin, chymotrypsin and phospholipases. It exerts its effect within the gastrointestinal (GI) tract.

The effect of orlistat on the pharmacokinetics and pharmacodynamics of warfarin in healthy volunteers.

To assess the effect of orlistat on the pharmacokinetics and pharmacodynamics of warfarin, a third-party blind, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers. Each participant received single 30-mg oral doses of racemic warfarin sodium (Coumadin; DuPont Pharma, Wilmington, DE) administered on the eleventh day of treatment with 120 mg orlistat (treatment A) and placebo (treatment B) three times a day for 16 days; the two treatments were separated by a 3-week washout period. Serial blood samples were collected before and at appropriate intervals after each dose of warfarin to determine plasma concentrations of R-warfarin and S-warfarin and blood prothrombin time (PT) and plasma Factor VII concentration.

Oral and intravenous zidovudine pharmacokinetics: the effect of granulocyte-macrophage colony stimulating factor.

Combination therapy with zidovudine and recombinant human granulocyte-macrophage colony stimulating factor (rHu GM-CSF) may be warranted, owing to the bone marrow suppressive effects of zidovudine. A study of 16 patients, 8 of whom had acquired immune deficiency syndrome (AIDS) and 8 of whom were infected with human immunodeficiency virus (HIV) but were asymptomatic, was conducted. The effect of 4 days of rHU GM-CSF versus placebo on intermittent zidovudine therapy (200 mg every 8 hours) was evaluated using a randomized, cross-over study design.

Pharmacokinetics of isepamicin in paediatric patients.

The pharmacokinetics of isepamicin were evaluated in 50 paediatric patients ranging from newborn to 13 years old. Children with subdivided according to age: Group I (6-13 years); Group II (4 months to 6 years); Group III (16 days to 4 months); and Group IV (newborn to 16 days). All patients received isepamicin 7.

The influence of orlistat on the pharmacokinetics and pharmacodynamics of glyburide in healthy volunteers.

To assess the influence of orlistat on the pharmacokinetics and pharmacodynamics (the blood glucose-lowering effect) of glyburide, an open-label, placebo-controlled, randomized, two-way crossover study was done in 12 healthy male volunteers. Each subject received single 5-mg oral doses of glyburide (Micronase; The Upjohn Company, Kalamazoo, MI) on the fifth day of treatment with placebo (treatment A) and 80-mg orlistat (treatment B) three times a day for 4 1/3 days; the two treatments were separated by a five-day washout period. Serial blood samples were collected before and at appropriate intervals after each glyburide dose to determine plasma concentrations and blood glucose levels.

Retrospective population-based analysis of the dose-response (fecal fat excretion) relationship of orlistat in normal and obese volunteers.

Orlistat, an inhibitor of gastrointestinal lipases, limits the absorption of ingested fat and could become a potential treatment for obesity. This analysis was performed to elucidate the relationship between orlistat dose and intensity of inhibition of dietary fat absorption (assessed by measuring fecal fat excretion). In 11 phase I double-blind, placebo-controlled, parallel-group randomized studies, a total of 171 subjects received oral daily doses that ranged from 30 to 1200 mg orlistat or matching placebo three times a day for 9 to 10 days.

Human liver xanthine oxidase: nature and extent of individual variation.

Xanthine oxidase catalyzes the biotransformation of many drugs, including the thiopurines and methyl-xanthines. We used a sensitive radiochemical assay to determine optimal conditions for the assay of human liver xanthine oxidase activity. We then used those assay conditions to study the nature and extent of individual variation of xanthine oxidase activity in 189 samples of hepatic tissue from patients undergoing clinically indicated partial hepatectomy or open liver biopsy.

Thiopurine methyltransferase regulation in rat kidney: immunoprecipitation studies.

1. Thiopurine methyltransferase (TPMT) catalyses the S-methylation of thiopurine drugs. TPMT activity in the kidneys of male Sprague-Dawley (S-D) rats is approximately twice that present in the kidneys of female S-D rats, and this difference is testosterone-dependent.

Mouse kidney histamine N-methyltransferase: assay conditions, biochemical properties and strain variation.

Histamine N-methyltransferase (HNMT) catalyzes the N tau-methylation of histamine and structurally-related compounds. Levels of HNMT activity in the human red blood cell are regulated by inheritance. The inbred mouse is an ideal laboratory animal in which to study the genetics of inherited traits.

Human liver nicotinamide N-methyltransferase: ion-pairing radiochemical assay, biochemical properties and individual variation.

Nicotinamide N-methyltransferase (NNMT) catalyzes the N-methylation of nicotinamide, pyridine, and structurally related compounds. The products of this reaction are positively charged pyridinium ions that cannot be removed from aqueous solution by simple organic solvent extraction. We developed an assay for human liver NNMT based on the extraction of the positively charged reaction product into 60% isoamyl alcohol in toluene in the presence of the ion-pairing reagent 1-heptanesulfonic acid.

Pharmacokinetics of vincristine in cancer patients treated with nifedipine.

The pharmacokinetics of vincristine (VCR) after an intravenous bolus dose of 2 mg were studied in patients with cancer with and without a concomitant treatment with the calcium-entry blocker nifedipine (NIF). VCR concentrations were determined by a sensitive radioimmunoassay. Pharmacokinetic data were analyzed by a nonlinear weighted least-square regression program (SAS-NLIN).