A novel two-site enzyme immunoassay for the sensitive detection of beta-endorphin in specific human brain stem...

On the line of experiences previously made in the development of a two-site immunoradiometric assay (TS-IRMA), we generated, in the present study, a novel, sequential, noncompetitive two-site immunoenzymometric assay (TS-IEMA) for the determination of the non-acetylated form of human beta-endorphin (beta h-EP). At variance with other assays reported in the literature, but in analogy to the TS-IRMA, the TS-IEMA does not require previous separation of beta h-EP. The TS-IEMA detects beta h-EP in central nervous tissues at a very low detection limit, and to a high degree of reproducibility, precision, sensitivity, and accuracy. The newly developed assay was then used to determine beta h-EP levels in the tissues of distinct brainstem regions. Tissues were collected, by the Palkovits's punching technique, from a series of victims of "Sudden Infant Death Syndrome" and of miscellaneous infections. The TS-IEMA, combined with the punching technique, has revealed, in the measure of its application in the present study, an unprecedented high degree of resolution of the neurochemical architecture of beta h-EP in the human infantile brainstem.