Competitive enzyme immunoassay for urinary vanillylmandelic acid.

An enzyme immunoassay for urinary vanillylmandelic acid (VMA) using polyclonal antiserum and VMA-acetylcholinesterase conjugate as enzymatic tracer is described. Two different strategies for immunogen preparation were developed and enantioselectivity was demonstrated. Selected EIA allowed direct measurement of urinary VMA using D(-)-VMA as standard with good sensitivity (MDC = 0.1 mumol/l) and precision (CV less than 7% in 0.2-2.25 mumol/l range). Cross-reactivity with homovanillic acid (HVA) was 0.8% and less than 0.4% with other structurally related catecholamine metabolites. Intra- and inter-assay repeatability were less than 10% and recovery was 97.3% +/- 3%. Good correlation was obtained for EIA and HPLC analysis with normal and pathologic human urine samples (EIA = 0.895 HPLC-7.085, r2 = 0.98, n = 47).

Competitive enzyme immunoassay with monoclonal antibody for homovanillic acid measurement in human urine samples.

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 <10% in the 1.25-10 micromol/L range, and intra- and interassay CVs of <10%. Cross-reactivity with vanillylmandelic acid was 0.5% and <8% for other structurally related catecholamine metabolites. Parallelism of the EIA was shown in dilution studies and the correlation with routine HPLC assay in 62 normal and pathologic samples was EIA = 1.492 (HPLC) - 3.46, S(y/x), = 47.52, range = 4-1800 micromol/L, r2 = 0.977. Additional data concerning the validity of this assay were provided by HPLC analysis of urinary immunoreactive material.

Weak resistance to oxidation of native lipoproteins in Wistar rats.

We report an impressive decline in plasma lipid resistance to oxidation during Triton-WR-1339-induced hyperlipidemia in rats. This decline is associated with a modification in the balances between alpha-tocopherol and lipids and alpha-tocopherol and ascorbate. These results are consistent with a weak resistance of accumulated native lipoproteins in plasma to oxidation, during a 6-hour time course, and they suggest a misunderstood role of lipoprotein catabolic enzymes: to improve this characteristic. Conclusively, the results lead us to propound Triton-induced hyperlipidemia as an original model for studying the balance impairment between antioxidants and oxidizable substrates.

Changes in the serotonergic, noradrenergic and dopaminergic levels in the brain of scrapie-infected rats.

Levels of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylethyleneglycol (DHPG) were determined by high-performance liquid chromatography in different brain areas of scrapie-infected rats, 8.5 months after intracerebral inoculation of a rat-adapted strain from mice brain (C 506). At this time, rats developed early clinical signs of the disease. Scrapie-infected rats showed a reduction in the levels of 5-HT and 5-HIAA (frontal cortex, hippocampus, mesolimbic structure). Concentrations of DHPG decreased in the frontal and parietal cortices but remained unchanged in the hippocampus. DOPAC levels decreased in the striatum but not in the mesolimbic structure. These results confirm that the serotonergic, noradrenergic and dopaminergic systems are altered in the brain of scrapie-infected rats. They can partly account for clinical signs of scrapie and are in agreement with the scarce data provided by the postmortem analysis of Creutzfeldt-Jakob disease brains.

[Protein profile and immunoelectrophoresis of cerebrospinal fluid in neurology. Results and etiologies apropos of 430 tests]. / Profil protéique et immuno-électrophorèse du liquide céphalo-rachidien en neurologie. Résultats et étiologies à propos de quatre cent trente examens.

The study of 430 cerebrospinal fluids resulting from a neurological department showed 67 pathological medical cases according to following tests: intrathecal IgG synthesis and/or restricted heterogeneity with immuno-electrophoresis. We established a biological classification to approach the different etiologies. This classification was used for multiple sclerosis for which various strictly clinical classifications are not always able to diagnose the illness, as we show it for one of them.