Propoxyphene and its major metabolite, norpropoxyphene, have been quantitated in tissue specimens obtained from autopsies of people suspected of dying from propoxyphene overdosage. Gas-chromatographic determination of both propoxyphene and norpropoxyphene is essential because the blood concentration of the parent drug should be about 1.0 mg/liter or greater to attribute a death to the drug. The...

Plasma corticosterone (CORT) measures are a common procedure to detect stress responses in rodents. However, the procedure is invasive and can influence CORT levels, making it less than ideal for monitoring CORT circadian rhythms. In the current paper, we examined the applicability of a non-invasive fecal CORT metabolite measure to assess the circadian rhythm. We compared fecal CORT metabolite ...

OBJECTIVE To compare the metabolite profiles of venous effluent from both kidneys of individuals with unilateral atherosclerotic renal artery stenosis (ARAS) in order to directly examine how impaired renal blood flow impacts small-molecule handling in humans. METHODS We applied liquid chromatography-mass spectrometry based metabolite profiling to venous plasma obtained from the stenotic (STK)...

Single-cell analysis is an effective method to reveal cell heterogeneity. In their Research Article (e202302000), Yujun Song et al. report enzyme-loaded metal–organic framework-integrated microfluidic chip for highly efficient single-cell capture followed by real-time metabolite monitoring and analysis. By profiling intracellular glucose extracellular lactate, the platform could evaluate tumori...

Metabolomics, the systematic investigation of metabolites in biological fluids, cells or tissues, reveals essential information about metabolism and diseases. Metabolites have functional roles myriads processes, as substrates products enzymatic reactions, but also cofactors regulators large numbers biochemical mechanisms. These functions involve interactions with macromolecules. Yet, methods to...

This experiment aimed to investigate the effects of liquid metabolite (LM) produced by Lactobacillus plantarum and dietary putrescine (PUT) on growth, blood lipids, villus height (VH), crypt depth (CD) and polyamines (PAs) content of intestinal tissue and ileal digesta in chickens. Six treatments, replicated six time each, were factorial arrangements of two levels of LM (0 and 0.3%) and three l...

The pharmacokinetic and metabolite profiles of the antiretroviral agent tipranavir (TPV), administered with ritonavir (RTV), in nine healthy male volunteers were characterized. Subjects received 500-mg TPV capsules with 200-mg RTV capsules twice daily for 6 days. They then received a single oral dose of 551 mg of TPV containing 90 microCi of [(14)C]TPV with 200 mg of RTV on day 7, followed by t...