The relationship between P-endorphin and immunoglobulins was studied by examining the reaction of human and various animal IgGs to human β-endorphin radioimmunoassay (RIA). The dilution curves of the highly purified IgGs of the human, rabbit, rat, guinea pig and goat samples, demonstrated 0.18%, 0.052%, 0.038%, 0.008%, 0.008%, and 0.007% displacement reactivity respectively, to the human P-endorphin standard curve, with good parallelism. These immunological parallels to human β-endorphin suggest that a part of the amino acid sequence of human and mammalian IgG is similar to that of human P-endorphin. Therefore, it can be speculated that this relationship between IgG and β-endorphin arises from the same origin in evolutionary terms, a possibility that needs further clarification. Consequently, certain caution is warranted while interpreting the β-endorphin values obtained by the RIA using polyclonal antibody, particularly in a patient with high IgG levels, the cross-reaction makes the β-endorphin level spuriously high and to avoid IgG interference using a specific monoclonal antibody to synthetic β-endorphin is preferable to using polyclonal antibodies raised in animals.
Superoxide dismutase ISOD), catalase, hydroxyl radical (OH) scavengers and singlet oxygen (1O2) quenchers suppress the light signal from a xanthine oxidase/acetaldehyde system. Xanthine oxidase inhibitor allopurinol also suppresses the light signal from the system. Dilazep HCl (10-5-10-3M) suppresses the chemiluminescence in a concentration dependent manner without affecting the xanthine oxidase activity. These results suggest that dilazep exhibits a radical scavenger-like action.
An automated column-switching high-per formance liquid chromatographic method with ultraviolet detection is described for rapid and sensitive determination of the concentration of etizo- lam, an anti-anxiety drug, in human serum or plasma. Samples were subjected to column-switching high-performance liquid chromatography using a short precolumn packed with a bovine serum albumin-coated ODS for sample clean-up and a reversed phase column (TSK gel ODS-80TM) for analytical separation. The detection limit of etizolam is 0.7 ng/ml serum. The recovery of etizolam added to serum (9.8-39.4 ng/ml) was approximately 100% with a standard deviation of 3% or less.
Serum levels of three tumor markers, CA50, sialyl SSEA-1 and Dupan-2 were determined in parallel with CA19-9 using serum samples from patients with various diseases including 170 patients with pancreatic cancer and up to 212 normal subjects. The objective was to determine whether any of those markers could compensate for the clinical drawbacks of CA19-9. None of these markers in a single determination was superior to CA19-9 in sensitivity and efficiency for the diagnosis of pancreatic cancer and the diagnostic efficiency of CA50 was almost comparable to that of CA19-9. Sialyl SSEA-1 was able to supplement CA19-9 to some extent in enhancing diagnostic specificity. No marker was superior to CA19-9 in the diagnosis of 17 patients with resectable pancreatic cancer. The combined use of CA19-9, sialyl SSEA-1 and Dupan-2 or of CA50, sialyl SSEA-1 and Dupan-2 increased the sensitivity but not the specificity. Thus, the diagnostic efficiency of these markers in combination was considered comparable to that of a single determination of CA19-9.
We found that adding ditaurobilirubin (DTB) to normal adult serum decreased dye-binding with albumin in the bromcresol purple (BCP) method for serum albumin determination. The mixing of DTB and normal adult serum resulted in the appearance of delta bilirubin (Bd)-like material with the same retention time as authentic Bd on HPLC analysis. This bilirubin bound firmly to serum albumin. We consider that the peptide bond present in DTB reacts with serum albumin.