Following superior mesenteric artery occlusion and revascularization in dogs all animals died in a circulatory collapse state. However, pretreatment by aminoguanidine, the strong and specific inhibitor of diamine oxidase, accelerated the circulatory break-down significantly and increased the venous plasma histamine concentrattions up to levels which also in normal dogs are effective in the circulatory system. Furthermore, the haematocrit increased significantly more in the aminoguanidine-treated animals than in the dogs treated by saline. No changes in plasma diamine oxidase activity were observed in saline-treated animals during intestinal ischemia and following revascularization. In aminoguanidine-treated animals no enzymic activity could be measured. The results were interpreted by a protective role of intestinal diamine oxidase in intestinal ischemia. Enhancement of the enzymic activity in patients, for instance by heparin, may be helpful in mesenteric infarction disease.

Among various vasoactive substances histamine was also suggested to induce circulatory arrest following superior mesenteric artery occlusion. Thus the involvement of the histamine-diamine oxidase system was studied in intestinal ischaemia using three animal species. In pigs, dogs and rabbits aminoguanidine, the specific inhibitor of diamine oxidase, shortened the survival time after mesenteric infarction. Under these conditions the diamine oxidase activity in the intestinal wall was reduced in animals treated by saline whereas the histamine content was not altered significantly. Plasma histamine levels were increased considerably in the portal vein of pigs during the revascularization period if the animal were pretreated by aminoguanidine. Similar findings were obtained in dogs. It was concluded that in all three species investigated the diamine oxidase protects the organism against the deleterious effects of at least one of its vasoactive substrates-histamine.

The growing need for emergency imaging has greatly increased the number of conventional X-rays, particularly for traumatic injury. Deep learning (DL) algorithms could improve fracture screening by radiologists and emergency room (ER) physicians. We used an algorithm developed for the detection of appendicular skeleton fractures and evaluated its performance for detecting traumatic fractures on conventional X-rays in the ER, without the need for training on local data. This algorithm was tested on all patients (N = 125) consulting at the Louis Mourier ER in May 2019 for limb trauma. Patients were selected by two emergency physicians from the clinical database used in the ER. Their X-rays were exported and analyzed by a radiologist. The prediction made by the algorithm and the annotation made by the radiologist were compared. For the 125 patients included, 25 patients with a fracture were identified by the clinicians, 24 of whom were identified by the algorithm (sensitivity of 96%). The algorithm incorrectly predicted a fracture in 14 of the 100 patients without fractures (specificity of 86%). The negative predictive value was 98.85%. This study shows that DL algorithms are potentially valuable diagnostic tools for detecting fractures in the ER and could be used in the training of junior radiologists.

In the gastric mucosa of human subjects and of various mammals methylation was accepted as the main pathway of histamine catabolism. However, augmentation of gastric acid secretion by aminoguanidine, the strong inhibitor of diamine oxidase, indicated an influence of diamine oxidase activity on this secretory process. Therefore a careful reinvestigation of the occurrence of diamine oxidase activity was started from the distal duodenum in the direction of the cardia. In all species studied, diamine oxidase activity decreased from distal duodenum towards the pylorus. In dogs, landrace pigs and in human subjects the diamine oxidase activity clearly exceeded the pyloric borderline gradually becoming zero in corpus or fundus. In rabbits, however, and especially in mini-pigs no diamine oxidase activity was found beyond the pylorus. Among individuals gastric diamine oxidase activity showed a variable prevalence and could not be found regularly in all the subjects. In one patient with prepyloric ulcer a strong influence of pathophysiological processes on gastric diamine oxidase activity could be suspected. Thus, in every alteration of the gastric mucosa under experimental or clinical conditions also an alteration of gastric diamine oxidase activity should be taken into account.