We describe a "high-performance" liquid-chromatographic procedure for measuring 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid) in urine. The compound is quantitatively extracted from urine by use of an automated system, including an anion-exchange resin. After elution from the resin and concentration by air drying, the urine extract is chromatographed on an octyl silica column, with u...

The monamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), vanillylmandelic acid (VMA), and 4-hydroxy-3-methoxyphenylglycol (HMPG) were analysed in CSF from different regions of the CSF system to study the caudocranial concentration gradient of the metabolites. Four consecutive 10 ml fractions of CSF were withdrawn in 17 patients during the course of four minutes. Th...

Nanostructured ZrO2-based materials with their biocompatibility, excellent electrical, and surface charge properties became one of the best candidates for electrochemical sensing applications. Here, synthesis Zr1-xCuxLaxO2 compounds was achieved in nanoscale fully characterized using XRD, TEM, DRS, cyclic voltammetry. A mixture monoclinic cubic phases detected undoped ZrO2 (Z sample, x = 0). Fo...

The relationship between homovanillic acid (HVA), vanillylmandelic acid (VMA), and creatinine in the urine of 6 month old babies has been studied and reference ranges in the form of centiles constructed for HVA and VMA against creatinine. Over 10,000 urine samples were collected from babies in four health districts in the north of England. HVA and VMA concentration, either independently or when...

A fast competitive enzyme immunoassay (EIA) for measuring homovanillic acid in human urine samples was developed with a monoclonal antibody and acetylcholinesterase as enzyme label. Enzyme detection was performed by an easy colorimetric assay. Monoclonal antibodies were screened on the basis of sensitivity, specificity, and correlation studies. EIA has a detection limit of 0.5 micromol/L, a CV ...

We describe a simple and rapid method for measuring catecholamine metabolites in urine collected on filter paper. By this method, "high-performance" liquid chromatography, urinary vanillylmandelic acid and homovanillic acid can be measured within 15 min after being eluted from filter paper treated with tartrate buffer. One hundred urine samples can be pretreated within 2 h and 100-120 samples a...

Urinary 5-hydroxyindoleacetic acid (5-HIAA), vanillylmandelic (VMA), homovanillic (HVA), catecholamines and metanephrines are produced in excess by catecholamine-producing tumors. These biogenic amines unstable at low or high pH require hydrochloric (HCl) to prevent their degradation. However, HCl addition may result very causing degradation deconjugation of several metabolites. This study eval...