Reliability and practicability of the fluorometric-fluoroenzymatic histamine determination in pathogenetic studies on peptic ulcer: Detection limits and problems with specificity

Abstract

Histamine, among various "biologic-physiologic" abnormalities, is considered as a pathogenetic factor in chronic duodenal ulcer disease. The 10-30 per cent difference between its concentration in gastric and duodenal mucosa of patients compared to healthy controls, however, has to be demonstrated to be specific for the disease. It has to be shown to be neither a methodological artefact nor a common effect, concomitant factor or consequence. This study, after a series of pathogenetic trials examines systematic errors (biases) in the fluorometric-fluoroenzymatic histamine assay under the conditions of field studies including tests on specificity over a time period of 10 years. It concentrates on sensitivity (detection limits) and specificity of a standard technique described herein. A modified Shore procedure for large scale assays in human biopsies was developed including reference luminescence values for all reagents, cleaning material and glassware, reduction of OPD concentration to 0.05%, purification of n-heptan, omission of centrifugation steps in the extraction procedure and use of 2 ml 1 M HClO4 in the homogenization step to prevent losses of histamine due to adherence to the mechanical homogenizer. This assay was sensitive enough to measure histamine without difficulty in any biopsy taken. The detection limit was 3 ng/biopsy, but the smallest quantities of the amine ever obtained were 10.6 and 18.3 ng/biopsy (depending on both histamine content and biopsy weight). A series of problems had to be solved both in achieving and demonstrating specificity. It had to be defined not only for the assay in general, but also for assessing the difference in histamine content between ulcer patients and healthy controls. Exogenous more than endogenous fluorescing material interfering with the determination had to be excluded. A series of pitfalls were detected which had to be overcome in demonstrating the specificity of the assay by physicochemical and enzymatic tests. The specificity of the identification tests was more often impaired than the histamine assay itself. Fluorescing material interfering with the assay occurred in the homogenization, extraction and condensation steps, was found in water, OPD, the organic solvents, the cleaning material and in all kinds of plastic vessels. Plasticizers were shown by physicochemical characteristics including fluorescence spectra to be most likely responsible for this interfering material. Rules were developed to exclude such hazards in specificity in longterm pathobiochemical studies. Enzymatic identification test were applied to exclude endogenous fluorecing substances interfering with the standard technique. Simil

Histamine and duodenal ulceration in renal transplant recipients.

“…These values were comparable to the average findings reported by the Marburg group of investigators. 16 In the present study we have found that the gastric mucosal histamine content in corpus and antrum is significantly lower in renal transplant patients, with or without an ulcer, than in normal controls. The magnitude of these reductions is similar to that seen in patients with chronic duodenal ulcer,'7 in whom, as in our patients, the reduction is not specific for the acid producing stomach but is also present in the gastric antrum.…”

Reliability of current techniques for histamine determination in human plasma: The european external quality control study 1988

“…The rapid development of new technologies and the functional brilliance of new equipment in our days have offered many possibilities to produce a whole battery of principally new or modified assays for histamine determination [10]. This study aimed to test all principal histanrine assays used today in different laboratories in Europe to measure reliably plasma histamine levels in man in a clinically significant range.…”

Histamine release and pseudoallergic reactions induced by radiographic contrast media: Comparison of Angiographin®, Hexabrix® and Telebrix® using anin vivo canine model

“…Two had high osmolalities: Angiographin *~ (Schering, Berlin), INN name amidotrizoate, 1530 mOsm/kg, iodine content 306 mg/ml; Telebrix | (Byk Gulden, Konstanz), INN name Ioxithalamate, 1860 mOsm/kg, iodine content 300 mg/ml and one had a lower osmolality: Hexabrix | (Byk Gulden, Konstanz), INN name ioxaglate, 600 mOsm/kg, iodine content 320 mg/ml. The reagents for the histamine assays were as described by Lorenz and coworkers [4,5]. None of the agents tested interferred with the histamine assays.…”