Detection of macroenzymes in serum by high-performance gel permeation chromatography

Dancing eye syndrome and hyperphosphatasemia

An 11-month-old boy with a relapsing dancing eye syndrome associated with elevation of serum alkaline phosphatase, lactate dehydrogenase, and aminotransferase activities is reported. During two clinical episodes the serum alkaline phosphatase activity increased up to four times the upper reference limit, remained elevated for a few weeks and normalized gradually in parallel with clinical improvement under steroid therapy. We found no evidence of liver or bone pathology nor of a neural crest tumor. The association between dancing eye syndrome and hyperphosphatasemia has not yet been described. The beneficial effect of the steroid therapy strengthens the hypothesis of an autoimmune origin.

Bioanalysis of the neuropeptide des-enkephalin-gamma-endorphin by high-performance liquid chromatography with on-line sample pretreatment using gel permeation and solid-phase isolation

A bioanalytical method is described that allows the determination of a number of beta-endorphin-related peptides. The method is based on the application of fluorescence detection after high-performance liquid chromatography followed by post-column derivatization with o-phthaldialdehyde. Concentrations exceeding 10-25 ng/ml could be determined by using conventional fluorescence detection, whereas lower concentrations demand the use of laser-induced fluorescence detection. The sample pretreatment includes the use of on-line gel permeation, on-line solid-phase isolation and heart cutting of a peak from reversed-phase gradient elution. The sample pretreatment procedure does not discriminate between the dodecapeptide des-enkaphalin-gamma-endorphin (DE gamma E) and its metabolites in order to obtain similar recoveries for all components. The final chromatographic phase system is based on ion-pair formation, which permits the separation of DE gamma E from its metabolites and degradation products. The optimized procedure allows the determination of these peptides in plasma at concentration levels down to about 1 ng/ml, demanding a sample volume of 1 ml.