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Biomedical subjects

E Iwashita

Publications and source records attributed to E Iwashita.

8 recordsLinked to original sources
PubMed1998

Activation of microvascular endothelial cells in active ulcerative colitis and detection of inducible nitric oxide synthase.

Endothelial nitric oxide (NO) synthase (NOS) that is expressed constitutively on microvascular endothelium is believed to be essential to systemic and/or local vascular integrity. Endothelial cells (ECs) were reported to express inducible NOS (iNOS) under some conditions iNOS expression indicates vascular activation. In this study we examined microvascular activation using ECs obtained from patients with ulcerative colitis (UC). We cultured ECs from the mesenteries of surgical UC patients and assayed NOS activity by NADPH-diaphorase cytochemistry and immunocytochemistry with an anti-iNOS antibody. Strong NOS activity was demonstrated on the cells from UC patients (5/5), whereas no activity was detected on the cells from cancer patients and human umbilical vein endothelial cells (HUVEC 0/5, 0/5). Strong iNOS activity was detected by immunoreaction, and large amounts of NO generated were detected by the conversion from [14C]arginine to [14C]citrulline (HUVEC 624+/-376 vs. EC-UC 1,492+/-233 dpm). These results suggest the possibility that ECs express spontaneous and continuous iNOS in active UC. They indicate a close relationship of vascular activation with the pathogenesis of UC.

Adult↗
PubMed1998

Greatly increased mucosal nitric oxide in ulcerative colitis determined in situ by a novel nitric oxide-selective microelectrode.

Although current nitric oxide (NO) electrodes are simple, selective and sensitive, they are fragile and hard to use in clinical studies of patients. By preparing an improved NO electroneedle that overcomes these defects, we directly measured mucosal NO concentrations in 11 patients (six male, five female; mean 26.0 years old) with ulcerative colitis (UC) and five normal volunteers (three male, two female; mean 28.3 years old) in situ. An electroneedle was inserted into colonic mucosa through a biopsy channel during colonoscopy. The information concerning the concentration of NO generated and the appearances of the colonic mucosa at the same site were obtained simultaneously. In the ulcerative colitis patients, NO concentrations were significantly increased at all 24 mucosal sites tested. These included sites where: there was an absence of visible inflammation (five sites); the mucosa was mildly inflamed (eight sites); the mucosa was moderately inflamed (five sites); or severely inflamed (six sites). The NO concentrations in ulcerative colitis patients were 12-72 times higher than the NO levels in normal controls (10 sites). At the same 10 sites in four ulcerative colitis patients, the high NO concentrations were decreased by 53% after glucocorticoid treatment. These data are consistent with those of previous studies utilizing different NO electrodes. Excess mucosal NO is generated from inducible NO synthase in the inflamed mucosa itself and the invading inflammatory cells. Our results suggested that mucosal NO could be a marker for the extent of inflammation and its various actions correlated with the pathogenesis, natural history and prognosis of UC. Using the NO microelectrode system reported here, the concentration of NO generated can be monitored in real-time while observing the mucosal condition at the same site during endoscopy. This novel NO electrode may contribute to understanding the role of NO in colonic mucosal inflammation.

Adolescent↗
PubMed1998

Changes in colonic inflammation induced by dextran sulfate sodium (DSS) during short- and long-term administration of rebamipide.

Earlier studies have shown the antiinflammatory effects of histamine and nitric oxide (NO) in a model of colitis induced by DSS. However, the defense system against free radicals in this model remained unclear. The aim of this study was to evaluate the effects of rebamipide, which inhibits the production of free radicals, in this model using male Sprague-Dawley rats. Colitis induced by 1% DSS is characterized by slow, weak inflammation and is regarded as a chronic inflammation model. In contrast, colitis induced by 4% DSS is characterized by fast, strong inflammation and is regarded as the acute inflammation model. Endoscopic examinations, peripheral white blood cell (WBC) counts, and assays of myeloperoxidase activity (MPO) in homogenates of colon mucosa were performed after one week (4% DSS model) and eight weeks (1% DSS model). Inflammation of colon mucosa was milder in the rats given rebamipide compared with controls in both the 4% and 1% DSS model. Furthermore, peripheral WBC counts correlated with colonic MPO activity. These findings indicate that rebamipide works as an antiinflammatory agent in both acute and chronic inflammation.

Acute Disease↗
PubMed1995

High nitric oxide synthase activity in endothelial cells in ulcerative colitis.

Endothelial nitric oxide (NO) synthase, a unique NO synthase (NOS) isoform that is expressed constitutively by the vascular endothelium both in vivo and in vitro, is believed to be essential to systemic and/or local vascular integrity. NOS expression by endothelial cells may indicate vascular activation. We successfully established a simple method for the culture of microvascular endothelial cells from a small amount of tissue and investigated ulcerative colitis (UC), in which condition vascular factors have not been studied extensively. We cultured endothelial cells from the mesenteries of surgical patients with UC and assayed NOS activity by reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry. Strong NOS activity was demonstrated in the cells from all UC patients (5/5), whereas no activity was detected in the cells from human umbilical veins and the mesenteries of colon cancer patients (0/10 and 0/5, respectively). This strong NOS activity was not diminished by incubation with a high concentration of glucocorticoid, suggesting that it was constitutive. These results indicate a close relationship of vascular activation (high NOS activity) with the pathogenesis of UC.

Adult↗
PubMed1992

[Studies on the giardiasis as the zoonosis. III. Prevalence of Giardia among the dogs and the owners in Japan].

To obtain the basic data on the route of Giardia infection as zoonosis, of many regions in Japan, the feces from 2218 dogs were examined for detection of Giardia cysts. Giardia cysts were detected in 239 of the 2218 dogs (10.9%), which was the same as previous reports from America. None were found from the owners of 51 dogs in which Giardia cysts were detected. The detection rates of each facilities were, 68 of 366 (18.6%) from the breeder's kennels, 169 of 1811 (9.3%) in individual houses, 2 of 42 (4.9%) from research institutes. The detection rate of the breeder's kennels was higher than the other two facilities (p less than 0.05, p less than 0.001). The detection rates of Kanagawa and Shizuoka prefectures among 17 regions in Japan were higher than the others (p less than 0.001, p less than 0.05). Especially in Shizuoka, the rate of the individual houses was higher than from breeder's kennels. In kanagawa the rates of the individual houses and the breeders kennels were higher than the mean in Japan (p less than 0.001). Therefore one must instruct the breeders when teaching health education to included zoonosis, and that the detection rate of the age groups of less than 3 years old was high-221 of 1276 (17.3%). Since the detection rates of Giardia cysts in the dogs were low, the possibility that human infection acquired from dogs was low. However, some of patients with giardiasis we encountered had never been abroad, and it is not yet clear whether Giardia is strictly host specific or not, so attention should be paid to the possibility of cross-infection between man and animals.

Animals↗
PubMed1992

[Detection of intestinal parasites from dogs in Tochigi-City in 1979 and 1991].

To clarify whether sanitary and hygienic conditions surrounding humans and pet animals have improved or not, we examined feces from dogs for intestinal parasites in Tochigi in 1979 and 1991. Intestinal parasites were detected from 109 of the 262 dogs (41.9%) in 1979 and 86 of the 260 dogs (32.8%) in 1991. Among the parasites. Ancylostoma caninum, Tirchuris vulpis and Toxocara canis were most commonly detected, and their detection rates were higher in 1979. On the contrary, Dipylidium caninum, Strongyloides stercoralis, Isospora spp., which are important causes of human diseases, were detected at higher rates in 1991. In the dogs of outdoor feeding, the detection rates of parasites were markedly decreased, but slightly increased in the dogs of indoor feeding in 1991. These results suggest that sanitary conditions surrounding pet animals have not been sufficiently improved, in spite of the fact that humans are in more contact with their pet animals.

Animals↗