Inhibition of prostacyclin and thromboxane biosynthesis in healthy volunteers by single and multiple doses of acetaminophen and indomethacin.

This double-blind, randomized crossover study assessed the effect of acetaminophen (1000 mg every 8 hours) versus indomethacin (50 mg every 8 hours) versus placebo on cyclooxygenase enzymes (COX-1 and COX-2). Urinary excretion of 2,3-dinor-6-keto-PGF1α, (prostacyclin metabolite, PGI-M; COX-2 inhibition) and 11-dehydro thromboxane B2 (thromboxane metabolite, Tx-M; COX-1 inhibition) were measured after 1 dose and 5 days of dosing. Peak inhibition of urinary metabolite excretion across 8 hours following dosing was the primary end point. Mean PGI-M excretion was 33.7%, 55.9%, and 64.6% on day 1 and 49.4%, 65.1%, and 80.3% on day 5 (placebo, acetaminophen, and indomethacin, respectively). Acetaminophen and indomethacin inhibited PGI-M excretion following single and multiple doses (P = .004 vs placebo). PGI-M excretion inhibition after 1 dose was similar for indomethacin and acetaminophen, but significantly greater with indomethacin after multiple doses (P = .006). Mean Tx-M excretion was 16.2%, 45.2%, and 86.6% on day 1 and 46.2%, 58.4%, and 92.6% on day 5 (placebo, acetaminophen, and indomethacin, respectively). Tx-M excretion inhibition following 1 dose was reduced by acetaminophen (P ≤ .003). Indomethacin reduced Tx-M excretion significantly more than acetaminophen and placebo after single and multiple doses (P ≤ .001). Acetaminophen and indomethacin inhibited COX-1 and COX-2 following a single dose, but acetaminophen was a less potent COX-1 inhibitor than indomethacin.

High-throughput simultaneous analysis of RNA, protein, and lipid biomarkers in heterogeneous tissue samples.

BACKGROUND: With expanding biomarker discovery efforts and increasing costs of drug development, it is critical to maximize the value of mass-limited clinical samples. The main limitation of available methods is the inability to isolate and analyze, from a single sample, molecules requiring incompatible extraction methods. Thus, we developed a novel semiautomated method for tissue processing and tissue milling and division (TMAD). METHODS: We used a SilverHawk atherectomy catheter to collect atherosclerotic plaques from patients requiring peripheral atherectomy. Tissue preservation by flash freezing was compared with immersion in RNAlater®, and tissue grinding by traditional mortar and pestle was compared with TMAD. Comparators were protein, RNA, and lipid yield and quality. Reproducibility of analyte yield from aliquots of the same tissue sample processed by TMAD was also measured. RESULTS: The quantity and quality of biomarkers extracted from tissue prepared by TMAD was at least as good as that extracted from tissue stored and prepared by traditional means. TMAD enabled parallel analysis of gene expression (quantitative reverse-transcription PCR, microarray), protein composition (ELISA), and lipid content (biochemical assay) from as little as 20 mg of tissue. The mean correlation was r = 0.97 in molecular composition (RNA, protein, or lipid) between aliquots of individual samples generated by TMAD. We also demonstrated that it is feasible to use TMAD in a large-scale clinical study setting. CONCLUSIONS: The TMAD methodology described here enables semiautomated, high-throughput sampling of small amounts of heterogeneous tissue specimens by multiple analytical techniques with generally improved quality of recovered biomolecules.

Quantitative measurement of cysteinyl leukotrienes and leukotriene B4 in human sputum using ultra high pressure liquid chromatography-tandem mass spectrometry.

The role of leukotrienes (LTs) in airway inflammatory diseases, such as asthma, has been extensively reported. The measurement of LTs in sputum supernatants, which is commonly done via enzyme immunoassays (EIAs), may prove to be useful for assessing airway inflammation. Despite the many advantages of EIA, these methods suffer from a lack of selectivity. Therefore, a selective and reliable method for the analysis of LTs in human sputum is needed. In this study we developed and validated a sensitive and specific method using ultra high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), to measure simultaneously cysteinyl leukotrienes (CysLTs) and leukotriene B4 (LTB4) in human sputum. Sputum supernatants obtained by ultracentrifugation were stabilized by protease inhibitors, spiked with stable isotopic internal standards, and subjected to solid phase extraction (SPE) and UHPLC separation. Multiple reaction monitoring (MRM) transitions were optimized and measured on a mass spectrometer. The limit of detection (LOD) for LTE4 and LTB4 was 9.8 and 19.5 pg/mL, respectively. The lower limit of quantitation (LLOQ) for LTE4 and LTB4 was 19.5 and 39.0 pg/mL, respectively. The dynamic range of the LTE4 assay was from 9.8 to 5000 pg/mL, whereas for the LTB4 assay was from 19.5 to 10,000 pg/mL. The intra- and inter-day % coefficient of variation (%CV) was <6.5% and <10%, for both LTE4 and LTB4, respectively. Spike recovery ranged from 105% to 111% for both analytes. In addition, twenty-two sputum samples were analyzed for cysLTs and LTB4. Fourteen of these samples were purchased commercially and eight were collected during the course of a clinical trial. LTB4 was detectable in all samples tested and it ranged from 79 to 7220 pg/mL. LTE4 was detectable in most of the sputum samples (12.3-891 pg/mL), whereas LTC4 and LTD4 were below limit of detection for majority of sputum samples. The in vitro conversion of LTC4 and LTD4 into LTE4 was observed. The measurement of LTB4 was sensitive to low pH and high temperature. The use of UHPLC-MS/MS method will allow a more accurate and reliable quantitation of LTs in human sputum, which in turn, may lead to a better understanding of the role of LTs in airway disease pathways and the application in associated clinical treatments.

Plasma MicroRNAs as sensitive and specific biomarkers of tissue injury.

BACKGROUND: MicroRNAs (miRNAs) are endogenous, small noncoding RNAs. Because of their size, abundance, tissue specificity, and relative stability in plasma, miRNAs hold promise as unique accessible biomarkers to monitor tissue injury. METHODS: We investigated the use of liver-, muscle- and brain-specific miRNAs as circulating biomarkers of tissue injury. We used a highly sensitive quantitative PCR assay to measure specific miRNAs (miR-122, miR-133a, and miR-124) in plasma samples from rats treated with liver or muscle toxicants and from a rat surgical model of stroke. RESULTS: We observed increases in plasma concentrations of miR-122, miR-133a, and miR-124 corresponding to injuries in liver, muscle, and brain, respectively. miR-122 and miR-133a illustrated specificity for liver and muscle toxicity, respectively, because they were not detectable in the plasma of animals with toxicity to the other organ. This result contrasted with the results for alanine aminotransferase (ALT) and aspartate aminotransferase, which were both increased with either organ toxicity. Furthermore, miR-122 exhibited a diagnostic sensitivity superior to that of ALT when the results were correlated to the liver histopathologic results. The miR-124 concentration increased in the plasma of rats 8 h after surgery to produce brain injury and peaked at 24 h, while the miR-122 and miR-133a concentrations remained at baseline values. CONCLUSIONS: These results demonstrate that tissue-specific miRNAs may serve as diagnostically sensitive plasma biomarkers of tissue injury.

A high-precision fluorogenic cholesteryl ester transfer protein assay compatible with animal serum and 3456-well assay technology.

Cholesteryl ester transfer protein (CETP) is a serum component responsible for both cholesteryl ester and triglyceride trafficking between high-density lipoprotein (HDL) and the apolipoprotein B (apoB)-containing very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL). Several fluorescence-based assays that monitor these transfers have been reported, but to date such assays have suffered from a low signal/background (S/B) ratio and have been described for use only in relatively purified in vitro systems. We have modified the more advanced of these assays to incorporate a noninterfering, nondiffusable fluorescence quencher into previously described cosonicate particles, often referred to as microemulsions. This simple improvement resulted in particles that had an average threefold enhanced S/B window over particles without quenchers but that continued to show the essential properties of a catalytic assay, including catalysis to a single endpoint, excellent linearity with protein and particle concentration, and an appropriate sensitivity to inhibition. This reduced assay noise allowed the subsequent development of protocols for the direct measure of cholesteryl ester (CE) transfer activity resident in human and animal serum as well as the development of 384- and 3456-well screening protocols with good precision and accuracy. Thus, by expanding the dynamic response window of the assay, we have created an assay generalizable to many settings.

Efficacy and safety of intranasal peptide YY3-36 for weight reduction in obese adults.

CONTEXT: The gastrointestinal peptide hormone, peptide YY(3-36) (PYY(3-36)), is implicated to be a postprandial satiety factor. OBJECTIVE: The aim of this study is to assess the safety, tolerability, and efficacy of intranasal PYY(3-36) to induce weight loss in obese patients. DESIGN: The study was designed as a randomized, 2-wk, single-blind placebo run-in followed by a 12-wk double-blind, placebo-controlled treatment period. SETTING: The study was set within a private and institutional practice. PATIENTS: A total of 133 obese patients (body mass index, 30-43 kg/m(2); age, 18-65 yr) participated in the study. INTERVENTION: Placebo or 200- or 600-microg PYY(3-36) was administered as an intranasal spray 20 min before breakfast, lunch, and dinner in conjunction with a hypocaloric diet and exercise. MAIN OUTCOME MEASURE: Body weight was the main outcome measure. RESULTS: The number of patients completing 12 wk on the drug was 38 of 43 (88%), 31 of 44 (70%), and 12 of 46 (26%) for placebo, 200 microg three times a day (t.i.d.) and 600 microg t.i.d., respectively. In the 600 microg t.i.d. group, 27 of 46 (59%) patients discontinued due to nausea and vomiting. Among all randomized patients who took at least one drug dose and had a postbaseline measurement, the mean body weight change from baseline was -2.8, -3.7, and -1.4 kg for placebo, 200 and 600 microg, respectively. The least squares mean difference (95% confidence interval) between placebo and 200 microg was -0.9 (-2.6, 0.7) kg (P = 0.251). A difference of 2.11 kg was sought. No meaningful inference can be drawn from the few patients who completed the study on 600 microg. CONCLUSIONS: Intranasal PYY(3-36) as administered at these intervention doses and preprandial timing is not efficacious in inducing weight loss in obese patients after 12 wk of treatment.

A phase I trial of the dual farnesyltransferase and geranylgeranyltransferase inhibitor L-778,123 and radiotherapy for locally advanced pancreatic cancer.

PURPOSE: Preclinical and clinical studies have demonstrated that inhibition of prenylation can radiosensitize cell lines with activation of Ras and produce clinical response in patients with cancer. The aim of this study was to determine the maximally tolerated dose of the dual farnesyltransferase and geranylgeranyltransferase I inhibitor L-778,123 in combination with radiotherapy for patients with locally advanced pancreatic cancer. EXPERIMENTAL DESIGN: L-778,123 was given by continuous intravenous infusion with concomitant radiotherapy to 59.4 Gy in standard fractions. Two L-778,123 dose levels were tested: 280 mg/m2/day over weeks 1, 2, 4, and 5 for dose level 1; and 560 mg/m2/day over weeks 1, 2, 4, 5, and 7 for dose level 2. RESULTS: There were no dose-limiting toxicities observed in the eight patients treated on dose level 1. Two of the four patients on dose level 2 experienced dose-limiting toxicities consisting of grade 3 diarrhea in one case and grade 3 gastrointestinal hemorrhage associated with grade 3 thrombocytopenia and neutropenia in the other case. Other common toxicities were mild neutropenia, dehydration, hyperglycemia, and nausea/vomiting. One patient on dose level 1 showed a partial response of 6 months in duration. Both reversible inhibition of HDJ2 farnesylation and radiosensitization of a study patient-derived cell line were demonstrated in the presence of L-778,123. K-RAS mutations were found in three of the four patients evaluated. CONCLUSIONS: The combination of L-778,123 and radiotherapy at dose level 1 showed acceptable toxicity in patients with locally advanced pancreatic cancer. Radiosensitization of a patient-derived pancreatic cancer cell line was observed.