Analysis of tryptophan metabolites and related compounds in human and murine tissue: development and validation of a quantitative and semi-quantitative method using high resolution mass spectrometry.

This study explores the metabolic differences between human and murine plasma in addition to differences between murine subcutaneous and visceral white adipose tissue. A quantitative and semi-quantitative targeted method was developed and validated for this purpose. The quantitative method includes tryptophan and its metabolites in addition to tyrosine, phenylalanine, taurine, B vitamins, neopterin, cystathionine and hypoxanthine.

Proenkephalin Decreases in Cerebrospinal Fluid with Symptom Progression of Huntington's Disease.

Objective: Identifying molecular changes that contribute to the onset and progression of Huntington's disease (HD) is of importance for the development and evaluation of potential therapies.

Methods: We conducted an unbiased mass-spectrometry proteomic analysis on the cerebrospinal fluid of 12 manifest HD patients (ManHD), 13 pre-manifest (preHD), and 38 controls. A biologically plausible and significant possible biomarker was validated in samples from a separate cohort of patients and controls consisting of 23 ManHD patients and 23 controls.

Measurement of hydroxychloroquine in blood from SLE patients using LC-HRMS-evaluation of whole blood, plasma, and serum as sample matrices.

Background: Hydroxychloroquine (HCQ) is the standard of care in the treatment of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and other inflammatory rheumatic diseases and potentially for the treatment in COVID-19 patients. Determination of HCQ for therapeutic drug monitoring (TDM) can be performed in whole blood (WB), serum, and plasma. Direct comparisons of WB, serum, and plasma levels of HCQ in patients with SLE have not previously been reported.

Targeted metabolomics of CSF in healthy individuals and patients with secondary progressive multiple sclerosis using high-resolution mass spectrometry.

Introduction: Standardized commercial kits enable targeted metabolomics analysis and may thus provide an attractive complement to the more explorative approaches. The kits are typically developed for triple quadrupole mass spectrometers using serum and plasma.

Objectives: Here we measure the concentrations of preselected metabolites in cerebrospinal fluid (CSF) using a kit developed for high-resolution mass spectrometry (HRMS).

A sensitive method detecting trace levels of levonorgestrel using LC-HRMS.

Objective: To develop a high resolution mass spectrometry (HRMS) method to quantify levonorgestrel (LNG) in serum.

Study Design: Levonorgestrel was extracted using solid phase extraction and measured using liquid chromatography (LC) HRMS.

Results: Low limit of quantification (LLOQ) was 25 pg/mL and low limit of detection (LLOD) was 12.