Neuroblastoma is a type of cancer that most often affects children. Neuroblastoma occurs when immature nerve cells called neuroblasts become abnormal and multiply uncontrollably to form a tumor. Most commonly, the tumor originates in the nerve tissue of the adrenal gland located above each kidney. Other common sites for tumors to form include the nerve tissue in the abdomen, chest, neck, or pelvis. Neuroblastoma can spread (metastasize) to other parts of the body such as the bones, liver, or skin.

Neuroblastoma

Ion suppression; a critical review on causes, evaluation, prevention and applications.

BACKGROUND: For many years, basic and clinical researchers have taken advantage of the analytical sensitivity and specificity afforded by mass spectrometry in the measurement of proteins. Clinical laboratories are now beginning to deploy these work flows as well. For assays that use proteolysis to generate peptides for protein quantification and characterization, synthetic stable isotope–labeled internal standard peptides are of central importance. No general recommendations are currently available surrounding the use of peptides in protein mass spectrometric assays.

CONTENT: The Clinical Proteomic Tumor Analysis Consortium of the National Cancer Institute has collaborated with clinical laboratorians, peptide manufacturers, metrologists, representatives of the pharmaceutical industry, and other professionals to develop a consensus set of recommendations for peptide procurement, characterization, storage, and handling, as well as approaches to the interpretation of the data generated by mass spectrometric protein assays. Additionally, the importance of carefully characterized reference materials—in particular, peptide standards for the improved concordance of amino acid analysis methods across the industry—is highlighted. The alignment of practices around the use of peptides and the transparency of sample preparation protocols should allow for the harmonization of peptide and protein quantification in research and clinical care.

/pdf/recommendations-for-the-generation-quantification-storage-2d8kgrmk8a.pdf

Recommendations for the Generation, Quantification, Storage, and Handling of Peptides Used for Mass Spectrometry–Based Assays

Liquid chromatographic methods for the quantification of catecholamines and their metabolites in several biological samples—A review

https://jcp.bmj.com/content/jclinpath/19/2/205.2.full.pdf

Clinical chemistry principles and technics

Urinary metanephrines by liquid chromatography tandem mass spectrometry: using multiple quantification methods to minimize interferences in a high throughput method.

Stable isotope-labeled internal standards are of great utility in providing accurate quantitation in mass spectrometry (MS). An implicit assumption has been that there is no “cross talk” between si...

Correction for isotopic interferences between analyte and internal standard in quantitative mass spectrometry by a nonlinear calibration function.

Simple dilute-and-shoot method for urinary vanillylmandelic acid and homovanillic acid by liquid chromatography tandem mass spectrometry.

Development and implementation of an HPLC-ECD method for analysis of vitamin C in plasma using single column and automatic alternating dual column regeneration.

Background: Serotonin, an endogenous biogenic amine found in enterochromaffin cells of the gastrointestinal tract, is produced in excess by carcinoid tumors. The primary urinary metabolite of serotonin, 5-hydroxyindoleacetic acid (5-HIAA), is used in the diagnosis and management of carcinoid disease. This study describes the development and validation of a dilute-and-shoot LC-MS/MS method for the measurement of 5-HIAA in urine. Methods: Samples were prepared by dilution in a 96-well format using an automated liquid handler. Chromatographic isolation of the analyte was achieved using a reversed-phase analytical column. A triple quadrupole mass spectrometer with electrospray ionization in positive mode was used for detection and quantification. Data were acquired by multiple reaction monitoring. Two transitions, quantifier (192.1/146.1) and qualifier (192.1/118.1), were monitored for the analyte and its stable isotope–labeled internal standard [5-hydroxyindole-4,6,7-d3-3-acetic-2,2-d2 acid (5-HIAA-d5)]. Chromatography was designed to elute the analyte outside of major suppression zones. Results: Injection-to-injection time was 4 min. The method was validated for linearity, limit of quantification, accuracy, and imprecision. The analytical measurement range was 0.5–100 mg/L. Coefficients of variation for within-run, between-day, and total imprecision ranged from 0.8% to 5.4%. The method produced accurate 5-HIAA concentrations and correlated well (R = 0.9876) with a comparison HPLC method. Matrix effects were evaluated by post-column infusion of urine samples. An analytical specificity study of endogenous compounds, vitamins, medications, and drugs showed minimal interference. Conclusions: A simple, inexpensive LC-MS/MS method was developed for measurement of 5-HIAA in urine. Results from the assay can be used clinically to assess carcinoid tumors.

/pdf/practical-lc-ms-ms-method-for-5-hydroxyindoleacetic-acid-in-kd11q66ml8.pdf

Zlatuse D. Clark

Papers

Urinary metanephrines by liquid chromatography tandem mass spectrometry: using multiple quantification methods to minimize interferences in a high throughput method.

Correction for isotopic interferences between analyte and internal standard in quantitative mass spectrometry by a nonlinear calibration function.

Simple dilute-and-shoot method for urinary vanillylmandelic acid and homovanillic acid by liquid chromatography tandem mass spectrometry.

Development and implementation of an HPLC-ECD method for analysis of vitamin C in plasma using single column and automatic alternating dual column regeneration.

Practical LC-MS/MS Method for 5-Hydroxyindoleacetic Acid in Urine