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Context: Repletion of lean body mass (LBM) that patients lose in human immunodeficiency virus (HIV) infection has proved difficult. In healthy, HIV-seronegative men, synergy between progressive resistance exercise (PRE) and very high-dose testosterone therapy has been reported for gains in LBM and muscle strength.Objective: To determine whether a moderately supraphysiologic androgen regimen, including an anabolic steroid, would improve LBM and strength gains of PRE in HIV-infected men with prior weight loss and whether protease inhibitor antiretroviral therapy prevents lean tissue anabolism.Design: Double-blind, randomized, placebo-controlled trial; post hoc analysis for effect of HIV-protease inhibitor therapy conducted from January to October 1997.Setting: Referral center in San Francisco, Calif.Patients: Volunteer sample of 24 eugonadal men with HIV-associated weight loss (mean, 9% body weight loss), recruited from an AIDS clinic and by referral and by advertisement.Intervention: For 8 weeks, all subjects received supervised PRE with physiologic intramuscular testosterone replacement (100 mg/wk) to suppress endogenous testosterone production. Randomization was between an anabolic steroid, oxandrolone, 20 mg/d, and placebo.Main Outcome Measures: Lean body mass, nitrogen balance (10-day metabolic ward measurements), body weight, muscle strength, and androgen status.Results: Twenty-two subjects completed the study (1 1 per group). Both groups showed significant nitrogen retention and increases in LBM, weight, and strength. The mean (SD) gains were significantly greater in the oxandrolone group than in the placebo group (5.6 [2.1] vs 3.8 [1.8] g of nitrogen per day [P=.05]; 6.9 [1.7] vs 3.8 [2.9] kg of LBM [P=.005]; greater strength gains for various upper and lower body muscle groups by maximum weight lifted [P = .02-.05] and dynamometry [P = .01 -.05]). The mean (SD) high-density lipoprotein cholesterol level declined 0.25 (0.14) mmol/L (9.8 [5.4] mg/dL) significantly in the oxandrolone group (P < .001 compared with placebo). Results were similar whether or not patients were taking protease inhibitors. One subject in the oxandrolone group discontinued the study because of elevated liver function test results.Conclusions: A moderately supraphysiologic androgen regimen that included an anabolic steroid, oxandrolone, substantially increased the lean tissue accrual and strength gains from PRE, compared with physiologic testosterone replacement alone, in eugonadal men with HIV-associated weight loss. Protease inhibitors did not prevent lean tissue anabolism. [ABSTRACT FROM AUTHOR]

Methods have been developed to screen for and confirm darbepoetin alfa, recombinant human EPO, and methoxy polyethylene glycol-epoetin (PEG-epoetin ) in horse plasma. All three methods screen samples with an enzyme-linked immunosorbent assay (ELISA) and confirm by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This report focuses on PEG-epoetin . The ELISA assay was able to detect PEG-epoetin at 0.02 ng/mL in 50 µL of horse plasma. Many samples had high background levels of immunoreactivity; however, introducing polyethylene glycol 6000 (PEG 6000) into the samples before the ELISA assay removed the high background and increased the apparent concentrations of PEG-epoetin . In samples collected following the administration of 100 µg of PEG-epoetin by the intravenous (IV), intramuscular (IM) and subcutaneous (SC) routes, PEG-epoetin was detectable up to 72, 144, and 120 h, respectively. The samples were prepared for LC-MS/MS analysis by extraction with anti-rHuEPO-antibodies-coated Dynabeads followed by digestion with trypsin. The LC-MS/MS confirmation method used the multiple reaction monitoring (MRM) scan mode to monitor four precursor-product ion transitions of the EPO-derived peptide T. All four transitions of T were detectable with S/N > 3. The limit of confirmation for PEG-epoetin was 1.0 ng/mL in 2 mL of horse plasma. The method successfully confirmed the presence of PEG-epoetin in a sample collected from a Mircera®-treated horse. Compared to PEG-epoetin , better sensitivity was achieved for darbepoetin alfa and recombinant human EPO. Darbepoetin alfa was detected in horse plasma four days after IM administration of 100 µg. Copyright © 2010 John Wiley & Sons, Ltd. Methods have been developed to screen for and confirm EPO analogs in horse plasma. The methods screen samples with an enzyme-linked immunosorbent assay (ELISA) and confirm by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This report focuses on PEG-epoetin β. [ABSTRACT FROM AUTHOR]