Makoto Nakao

Sensitive colorimetric assay of serum diamine oxidase

A simple and sensitive colorimetric assay for serum diamine oxidase (DAO) activity was based on a coupled reaction with peroxidase and a new chromogen, 10-(carboxymethyl-aminocarbonyl)-3,7-bis(dimethylamino) phenothiazine sodium salt (DA-67). In the presence of peroxidase and DA-67, peroxidase catalyzes the formation of methylene blue having an absorption maximum at 668 nm. The proposed method eliminates the interferences occurring in serum with use of ascorbate oxidase and stops the reaction with sodium diethyldithiocarbamate, leaving the methylene blue in the reaction mixture stable for about 2 h. Low normal basal values of serum DAO can be determined in the range 2.8-9.0 units/l. Since all reagents are commercially available the method is suitable for the clinical laboratory.

Usefulness of soluble dietary fiber for the treatment of diarrhea during enteral nutrition in elderly patients.

OBJECTIVES We investigated the clinical usefulness of soluble dietary fiber (SDF) for the treatment of diarrhea during enteral nutrition in elderly patients. METHODS This study included 10 men and 10 women (mean age +/- standard deviation: 79.3 +/- 5.1 y) who had diarrhea during long-term nutrition management. When administering SDF, the initial dose was 7 g and thereafter gradually increased at 1-wk intervals. After 4 wk, the administration was discontinued for 2 wk to confirm the effects of SDF. RESULTS After the administration of SDF, serum diamine oxidase activity significantly increased (P < 0.001): The water content of the feces decreased significantly after the administration of fiber (P < 0.01). The frequency of daily bowel movements also decreased significantly (P < 0.05). Simultaneously, the fecal features improved. Concerning intestinal flora, there were no significant changes in the total number of bacteria or the number of anaerobic bacteria. The fecal pH decreased significantly 4 wk after the administration of fiber (P < 0.05). The total level of short-chain fatty acids increased significantly 4 wk after the administration of fiber (P < 0.05). There were no significant changes in the various nutritional indices. CONCLUSIONS The administration of SDF is useful for controlling spontaneous, favorable bowel movement by improving symptoms of small intestinal mucosal atrophy and normalizing the intestinal flora.

Effect of Dietary Fiber on Morphine-induced Constipation in Rats

Morphine is used to alleviate chronic cancer pain. However, constipation is a major adverse effect that often detracts from the patients quality of life. In this study, we investigated the effectiveness of dietary fiber on morphine-induced constipation. Rats were fed on a normal diet or one containing either 10% or 20% apple fiber for two weeks before morphine was administered. In the control diet group, the fecal number and dry weight were decreased by treating with morphine in a dose-dependent manner. Moreover, the motility of the small and large intestines was reduced. The fecal number and weight were increased and the colon motility was promoted by dietary fiber, regardless of whether morphine was being administered. The dietary fiber increased the concentration of short-chain fatty acids (SCFAs) in the cecum. These results suggest that dietary fiber has a preventative effect on morphine-induced constipation by increasing SCFAs in the cecum, and thereby promoting colon motility in rats.

Congestion of Superior Mesenteric Veins and Small Bowel Mucosal Injury After Endoscopic Treatment of Esophageal Varices in Patients with Portal Hypertension

We investigated treatment-induced changes in venous return from the small bowel and small bowel intestinal mucosal injury induced by the treatment of esophageal varices in patients with portal hypertension. A total of 14 patients (age 59.8 ± 9.5 years, five women and 9 men) who received prophylactic treatment of esophageal varices between December 1998 and March 1999 were investigated. Diamine oxidase (DAO) activity was measured before and after treatment. Changes in blood flow of the portal and superior mesenteric veins were investigated by Doppler ultrasonography in six patients. A significant decrease in DAO activity was observed three days after treatment (11.5 ± 1.6 units/liter prior to treatment versus 8.6 ± 1.6 units/liter three days after treatment; P < 0.001). Decreases in superior mesenteric and portal venous flow velocity were observed in four and three patients, respectively. In two patients with an increase in the cross-sectional area of the superior mesenteric vein with delayed venous return, a marked decrease in DAO activity was observed three days after treatment. In patients with portal hypertension, rapid reduction of pooling of portal flow caused by the treatment of esophageal varices can induce transient congestion of the mesenteric venous system which can produce some small bowel mucosal injury.