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Biomedical subjects

H Asakura

Publications and source records attributed to H Asakura.

At least 361 records · Page 20Linked to original sources
PubMed1987

Increased lymphocyte transport by lipid absorption in rat mesenteric lymphatics.

The effect of olive oil administration on lymphocyte transport through mesenteric lymphatics was examined to see the possible involvement of nutritional absorption in lymphocyte traffic from the intestinal mucosa. After the olive oil administration to rats, remarkable increase in lymphocyte flux was observed within 2 h in lymph samples collected from rats with lymphatic fistula. The use of a high-speed microscopic video system made it possible to analyze accurately the lymphocyte transport in rapid movement that could not be detected by any of the ordinary video systems. The direct observation of mesenteric collecting lymphatics by this system showed an increment of lymphocyte transport from the intestinal mucosa by lipid absorption in 2 h. The contraction frequency of intestinal collecting lymphatics was also enhanced by olive oil administration. The densitometric analysis on video image was applied to estimate the extent of lipid absorption. The combination of a high-speed video system and the densitometric analysis revealed that the increase in lymphocyte flux occurred before lipid absorption reached its maximum and also demonstrated that the lymphocyte transport returned to control levels under the maximal absorptive condition. The results suggest that the fat absorption could be an important factor influencing the lymphocyte transport in the lymphatic system of intestine.

Absorption↗
PubMed1987

Inhibitory effect of somatostatin on cholera toxin-induced diarrhea and glycoenzyme secretion in rat intestine.

The effects of somatostatin on cholera toxin-induced secretory diarrhea and the appearance of glycoenzymes in the intestinal lumen and intestinal lymph were investigated in rat small intestine. After exposure to cholera toxin, marked fluid accumulation in the small intestinal tract and elevation of the jejunal mucosal cyclic AMP (cAMP) concentration were observed. The activity of alkaline phosphatase, aminopeptidase and sucrase increased in the intestinal lumen after toxin exposure. In intestinal lymph, alkaline phosphatase activity was increased after cholera toxin administration, while aminopeptidase activity remained unchanged. Somatostatin suppressed cholera toxin-induced secretory diarrhea, but it did not affect the elevated mucosal cAMP concentration. This peptide also inhibited the appearance of glycoenzymes in the intestinal lumen and lymph induced by cholera toxin administration. These results suggest that somatostatin exerts its inhibitory effects on cholera toxin-induced secretory diarrhea and on the appearance of glycoenzymes in the intestinal lumen and lymph by affecting processes beyond cAMP formation.

Alkaline Phosphatase↗
PubMed1987

Sulfasalazine and its metabolites attenuate respiratory burst of leukocytes--a possible mechanism of anti-inflammatory effects.

The effects of sulfasalazine and its metabolites, 5-amino salicylic acid and sulfapyridine on respiratory burst of polymorphonuclear leukocytes were investigated by determining not only luminol-dependent chemiluminescence for the detection of myeloperoxidase-mediated active oxidants, but also lucigenin-dependent chemiluminescence for the detection of superoxide anion. The present study showed that sulfasalazine, 5-amino salicylic acid and sulfapyridine attenuated active oxygen species from polymorphonuclear leukocytes at the concentrations comparable to clinical doses. Therefore, it was concluded that anti-inflammatory effects of sulfasalazine can be explained by the ability of sulfasalazine and its degraded compounds to scavenge active oxidants from polymorphonuclear leukocytes.

Aminosalicylic Acids↗
PubMed1987

Increased respiratory burst of leukocytes in inflammatory bowel diseases--the analysis of free radical generation by using chemiluminescence probe.

Respiratory burst of leukocytes was determined in Crohn's disease, intestinal Behçet's disease and ulcerative colitis by using chemiluminescence assay. Oxygen-derived free radicals of monocytes in Crohn's disease and those of polymorphonuclear leukocytes in intestinal Behçet's disease were significantly raised as compared with those of controls. In ulcerative colitis, respiratory burst activities of both polymorphonuclear leukocytes and monocytes were found to be highly associated with the disease activities. These results suggest that active oxygen species from leukocytes may participate in the formation of intestinal mucosal lesions in inflammatory bowel diseases via auto-oxidative process.

Adult↗
PubMed1987

Dynamic analysis of lymphocyte migration into Peyer's patches of rat small intestine.

Dynamic aspects of lymphocyte immigration into Peyer's patches were analyzed in rat small intestine using intravital fluorescence microscopy. Lymphocytes from intestine, lymph, and spleen were labeled with acridine orange in vitro and infused from the mesenteric artery of rats. There are three types of lymphocytes as characterized from their interaction with post-capillary venules of Peyer's patches immediately after infusion, and most of the lymphocytes passed through the microcirculatory bed without any interaction with venules. About 15 to 20 minutes later, the number of lymphocytes which stick to the Peyer's patches was increased and reached a maximum at 40 to 50 minutes. There was a difference in distribution pattern of infused lymphocytes between spleen cells and lymphocytes from intestinal lymph suggesting the complex control mechanism of lymphocyte migration into Peyer's patches.

Animals↗
PubMed1987

Alteration of T cell maturation and proliferation in the mouse thymus induced by serum factors from patients with ulcerative colitis.

Recently it has been reported that patients with ulcerative colitis (UC) often have thymus abnormalities, although the precise mechanisms which induce those abnormalities remain unclear. We have examined the effect of serum fractions from patients with UC and other colonic diseases on mouse thymus to clarify the possible existence of factors which have thymus growth activity. These fractions were separated from sera of patients with UC by gel filtration and anion exchange high performance liquid chromatography. In mice given UC serum fractions; (i) remarkable increases in weight and total cell number of the thymus were observed from day 4 to day 9; (ii) a significant increase in the number of peanut agglutinin (PNA)+ thymus cells was demonstrated using flow cytometry on day 9; (iii) on quantitative analysis of surface antigens the percentage of Lyt-2+ thymus cells decreased and that of L3T4+ thymus cells increased remarkably on day 13; the number of bright Thy-1.2+ cells and of dull Lyt-1+ cells increased. In contrast, the serum fractions from patients with other colonic diseases and from normal persons caused little change in mouse thymus throughout the study. The results suggest that factors fractionated from the serum of patients with UC disturb intra-thymic T cell maturation and enhance the proliferation of thymus cells.

Animals↗
PubMed1986

Malabsorption of long-chain fatty acid in cholera toxin-induced secretory diarrhea.

The effects of cholera toxin-induced diarrhea on the absorption of fatty acids of different chain lengths were investigated using rat small intestine. In the study using isolated jejunal loops, the absorption of the long-chain fatty acid, linoleic acid, into the intestinal mucosa was significantly impaired 90 min after the administration of linoleic acid micelles in the cholera toxin-treated rats. This reduction of linoleic acid absorption in the cholera toxin-treated rats was not found at 180 min. We could not find any mucosal accumulation of labeled linoleic acid or disturbance of triglyceride formation in the intestinal mucosa as compared with that of controls. The amount of linoleic acid transported into the intestinal lymph was delayed and reduced in cholera toxin-treated rats. Furthermore, the absorption of the medium-chain-length fatty acid, octanoic acid, was unchanged in the cholera toxin-treated rats. These results suggest that intestinal secretion induced by cholera toxin may delay the mucosal uptake and lymphatic transport of long-chain fatty acids. Cholera toxin may not affect triglyceride formation in the epithelial cells.

Animals↗
PubMed1986

Pathological findings of lymphangiectasia of the large intestine in a patient with protein-losing enteropathy.

Lymphangiectasia of the large intestine associated with protein-losing enteropathy is reported. A 33-yr-old man suffered from diarrhea, sometimes mixed with blood. Colonoscopic study revealed reddish and edematous mucosa with multiple flat elevated lesions and giant folds in the localized segment of the rectosigmoid. An intestinal clearance test of alpha 1-antitrypsin revealed the association of protein-losing enteropathy. Operation was performed successfully, resulting in a marked improvement of symptoms and laboratory data, especially serum total protein, albumin, IgG, and Leu-2a-positive cells (suppressor/cytotoxic T cells). Giant folds consisted of the submucosal edema and hyperplasia of the epithelial glands with cystic dilatation of glands, and flat elevated lesions consisted of mucosal and submucosal edema associated with intestinal lymphangiectasia, adipose tissue, and blood capillaries. The population of the Leu-2a-positive cells in the lamina propria and intraepithelial layer was decreased and that of the Leu-3a-positive cells (helper/inducer T cells) in the lamina propria was increased.

Adult↗