Histamine content, diamine oxidase activity and histamine methyltransferase activity in human tissues: fact or fictions?

To understand the role of histamine in the aetiology and pathogenesis of human diseases reliable data are urgently needed for the histamine content and for the activities of histamine-forming and -inactivating enzymes in human tissues. In order to make a substantial progress toward this aim a tissue-sampling programme during surgical interventions was carefully conceived and conducted. From March 1982 until January 1983 106 tissue specimens were taken from 56 patients who underwent surgery. Only healthy tissues, not injured or oedematous, and without adherent structures were taken by only one surgeon who was interested in this research and experienced in tissue preparation procedures in biochemistry. The times of 'warm' ischaemia during the operative procedures were visually estimated, the times between resection of the organs or specimens and deep-freezing of the tissues were precisely recorded. Compared to previous work in the literature and especially to our own work using the same assays for determination higher histamine contents were found in this study in most of the tissues, in particular in the gastrointestinal tract. Also the diamine oxidase activities were considerably higher in many organs, e.g. 3-4 times higher in the gastrointestinal tract when compared with those in publications of our group who used always the same analytical test. However, the histamine methyltransferase activities in this study were not at variance to those determined in previous investigations. Many of them were reported in this communication for the first time. Since the methods for histamine determination and those for measuring enzymic activities were not different in this study and in previous communications of our group we are convinced that the optimized tissue-sampling and -preparation techniques were responsible for the higher values in this communication. But the problem of the 'warm' ischaemia period could not be solved by sample-taking procedures of this type during operations. There are good reasons to prefer biopsy specimens for the analysis of histamine storage and metabolism in human tissues in health and disease, but - unfortunately - they are not always available.