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Biomedical subjects

H Umezawa

Publications and source records attributed to H Umezawa.

At least 19 recordsLinked to original sources
PubMed1999

Clinical evaluation of the effect of percutaneous transluminal angioplasty and intra-arterial papaverine infusion for the treatment of vasospasm following aneurysmal subarachnoid hemorrhage.

The clinical efficacy of percutaneous transluminal angioplasty and intra-arterial papaverine infusion for treatment of vasospasm following subarachnoid hemorrhage was investigated. Between 1990 and 1993, 84 patients were treated for cerebral vasospasm in National Defense Medical College Hospital. Angioplasty was performed for asymptomatic vasospasm in 18 patients and for symptomatic vasospasm in 12 patients. Intra-arterial papaverine infusion was performed for asymptomatic vasospasm in 10 patients and for symptomatic vasospasm in four patients. The other 40 patients were treated with standard conservative therapy including hypervolemic and hypertensive hemodilution. The outcomes of these patients were analyzed using the Glasgow Outcome Scale. The outcome tended to be better for patients treated with angioplasty, but not for those treated with papaverine infusion, than for those treated conservatively. Recurrence of vasospasm was more frequent after papaverine infusion than after angioplasty. Undesirable complications such as abrupt development of unconsciousness were experienced during papaverine infusion but not during angioplasty. We conclude that percutaneous transluminal angioplasty is superior to intra-arterial papaverine infusion for prevention and treatment of vasospasm following aneurysmal subarachnoid hemorrhage.

Angioplasty, Balloon↗
PubMed1999

Production of secretory component and pathogenesis of gastric cancer in Helicobacter pylori-infected stomach.

The purpose of this study was to examine the production of secretory component (SC) and immunoglobulin A (IgA) in the gastric mucosa with Helicobacter pylori infection and to investigate the influence of immunological reactions on various phases of infection (gastritis, intestinal metaplasia, gastric cancer). Production of SC and IgA was assessed by immunohistochemical staining in (1) endoscopic biopsy samples of H. pylori-eradicated cases (n = 25), and (2) surgically resected stomach tissues of H. pylori-positive gastric cancer cases, intestinal type (IGC, n = 25) and diffuse type (DGC, n = 25). Before eradication therapy, all samples showed positive staining of SC and IgA in epithelial cells, and IgA was also positive in plasma cells in the mucosal layer. H. pylori bacteria were positively stained for SC and IgA. After treatment, the degree of SC and IgA staining in epithelial cells was reduced with successful eradication; but with intestinal metaplasia, SC staining was positive regardless of the results of treatment. In nonmetaplastic mucosa, SC-positive cells were increased in the glandular neck zone to the surface mucosal layer; and the intensity of SC staining was increased in proportion to the degree of mucosal inflammation and IgA-positive cell aggregation. In intestinal metaplasia, SC was positive irrespective of the degree of inflammation. Most cancer foci also showed positive staining of SC, irrespective of histological type. Production of SC and IgA was thought to be a specific reaction against H. pylori infection, occurring from the early to the late stages and not limited to intestinal metaplasia. It was suggested that immunological reactions against H. pylori infection might generally be involved with the pathogenesis of intestinal metaplasia and both histological types of gastric cancer (IGC and DGC).

Gastric Mucosa↗
PubMed1998

Topographic distribution of Helicobacter pylori in the resected stomach.

OBJECTIVES: The aim of this study was to elucidate the prevalence of Helicobacter pylori and its distribution in order to clarify the frequency of H. pylori infection and the most appropriate site of endoscopic biopsy for studies of H. pylori infection associated with different gastric diseases. DESIGNS AND METHODS: Swiss role mucosal strips from 275 resected stomachs, which included the greater curvature, anterior wall and lesser curvature of the antrum, incisura and corpus, were stained with haematoxylin-eosin and H. pylori antibody. RESULTS: The prevalence of H. pylori infection was 97% in duodenal ulcers, 98% in gastric ulcers, 98% in intestinal-type carcinomas and 99% in diffuse-type carcinomas. H. pylori was present at a rate of 100% in any site in cases of duodenal ulcer, but was diffusely distributed in the antrum and patchily distributed in the corpus. The detection rate of H. pylori was 50-100% in gastric ulcers, 30-100% in intestinal-type adenocarcinomas and 63-100% in diffuse-type adenocarcinomas depending on the site of the stomach examined. CONCLUSIONS: The prevalence of H. pylori infection was very high in peptic ulcers of the duodenum and stomach and gastric carcinomas of Japanese patients. Biopsy specimens for evaluation of H. pylori infection should be taken routinely from both the greater curvature of the antrum and corpus. Immunohistochemical staining should be used to assay for H. pylori when few organisms are present or eradication therapy has been used.

Adenocarcinoma↗
PubMed1997

[Dural arteriovenous fistula presenting as acute-onset dementia: a case report].

We report here a unique case of acute-onset dementia caused by a posterior fossa dural arteriovenous fistula (AVF), which was successfully treated by surgical resection of the isolated transverse-sigmoid sinus combined with endovascular procedures. A 70-year-old female was admitted to our hospital with acute-onset dementia and pulsatile tinnitus on the left side. CT scan revealed a low-density area in the parieto-temporal region. Cerebral angiography revealed a dural AVF of the transverse-sigmoid sinus with retrograde drainage into cerebral cortical veins. After transarterial endovascular embolization of the dural AVF, a xenon-CT scan revealed increased cerebral blood flow. Four months postoperatively, however, she was admitted to our hospital again with seizure and aphasia due to recanalizaion of the dural AVF. After trans-arterial embolization, transvenous embolization was attempted, but was unsuccessful due to inaccessibility of the isolated sinus segment. Since this patient could not be cured by endovascular embolization, an open surgical resection of the isolated sinus segment was performed. Following this, CT scans revealed that the low density area present on the first admission had disappeared. The patient's dementia resolved postoperatively. We discuss the pathophysiological mechanism by which venous ischemia due to dural AVF can cause reversible dementia.

Acute Disease↗
PubMed1995

Stable prostacyclin improves postischaemic microcirculatory changes in hypertensive rats.

The prostacyclin analogue TTC-909 is incorporated in lipid microspheres and is chemically very stable. We examined the efficacy of TTC-909 on cerebral microcirculation following focal cerebral ischaemia. Focal cerebral ischaemia was produced by the occlusion of the distal middle cerebral artery in stroke-prone spontaneously hypertensive rats. Intravenous administration of TTC-909 (100 ng/kg/day) or vehicle was started 30 minutes after the occlusion and repeated for 7 days. On day 7, cerebral blood flow and blood-brain barrier permeability were measured autoradiographically. Brain oedema was estimated by the gravimetric method. The size of the infarction was calculated from area measurements on serial histologic sections. Treatment with TTC-909 resulted in significant improvement in regional blood flow in the ischaemic rim (p < 0.01) and the surrounding area (p < 0.05). With TTC-909 treatment, the increased permeability was significantly reduced in the ischaemic centre (p < 0.01) and rim (p < 0.05). A decrease in specific gravity in the ischaemic region and the remote non-ischaemic regions was prevented by the treatment (p < 0.01). We assumed that the efficacy of TTC-909 maintains the blood supply in the ischaemic area, improves disruption of the blood-brain barrier and prevents development of ischaemic oedema.

Animals↗
PubMed1995

[A penetrating injury of the extracranial vertebral artery: a case report].

Penetrating injury to the vertebral artery is a very rare accident and no case except ours has been reported to date in Japan. We reported a case of successful treatment of a penetrating injury by a nail to the left vertebral artery with the use of interventional radiologic procedure. A 27-year-old man was admitted to our hospital with a complaint of penetrating injury in his neck. Left vertebral angiography revealed that a nail had penetrated into the vertebral artery at the C6 level. Considering the possibility of thrombus formation around the metallic foreign body and the risk of uncontrollable bleeding, we performed embolization of the injured vertebral artery with Interlocking Detachable Coil.

Adult↗
PubMed1994

Blood-brain barrier, cerebral blood flow, and brain edema in spontaneously hypertensive rats with chronic focal ischemia.

This study was conducted to explore the participation of blood-brain barrier (BBB) permeability and cerebral blood flow (CBF) on the development of ischemic brain edema in rats with chronic arterial hypertension. Young spontaneously hypertensive rats were used, and focal ischemia was produced by occluding the distal middle cerebral artery (MCA). On day 7 after MCA occlusion, BBB permeability and CBF were measured by autoradiographic methods using 14C-alpha-amino-isobutyric acid (AIB) and 14C-iodoantipyrine. BBB permeability (transfer constant for AIB) was significantly higher in the ischemic center and periphery. The CBF of the ischemic cortex showed a graded reduction from the ischemic center to the surrounding area. The ischemic brain regions showed significantly decreased specific gravity. We conclude that SHRSP may be more vulnerable to BBB disruption after ischemia.

Animals↗
PubMed1994

Pituitary apoplexy caused by endocrine stimulation tests: a case report.

The case of a 60-year-old woman with a giant pituitary adenoma who suffered symptomatic pituitary apoplexy is reported. Hemorrhaging occurred during endocrine stimulation tests (triple bolus test) in and around the tumor. Both the level of consciousness and the hemiparesis improved after emergency decompression. Histologically the tumor was a chromophobe adenoma of the papillary type with diffuse hemorrhage. Subtotal removal of the tumor was successfully accomplished in a second operation. Routine anterior pituitary stimulation tests have the potential to develop pituitary apoplexy, and we advise that caution should be taken when such tests are planned. The possible mechanism resulting in bleeding is discussed.

Adenoma, Chromophobe↗
PubMed1994

Local cerebral blood flow and glucose metabolism in chronic focal ischaemia of stroke-prone spontaneously hypertensive rats.

The relationship between local cerebral blood flow (ICBF) and local cerebral glucose metabolism (ICGU) at the chronic stage of focal cerebral ischaemia was assessed in young stroke-prone spontaneously hypertensive rats (SHRSP) following occlusion of the distal middle cerebral artery (MCA). On day 7 following this occlusion, ICBF and ICGU were measured by autoradiographic methods using 14C-iodoantipyrine and 14C-2-deoxyglucose (2DG), respectively. The infarct was limited to the ipsilateral cerebral cortex. A narrow band of increased uptake of 14C-2DG was observed in the border zone at the periphery of infarcted areas. The ICBF in the ischaemic cortex revealed a graded reduction from the ischaemic centre to the surrounding tissues. A significant reduction in ICGU coupled to CBF was also observed in 4 of 13 selected noninfarcted regions ipsilateral to the MCA occlusion. The ischaemic regions had a significant increase in water content. The region with ischaemic oedema was limited to a narrow area compared with the findings regarding ICBF and ICGU. The SHRSP strain has more severe cerebral ischaemia, oedema formation, and metabolic derangement at the chronic stage of focal ischaemia, compared to normo-tensive animals.

Animals↗
PubMed1993

[Application of DNA fingerprinting to investigation of genetic relationships between laboratory rabbit strains].

It is well known that laboratory rabbits are not controlled genetically like laboratory mice and rats. In order to test the usefulness of DNA fingerprinting in investigation of genetic uniformity of the laboratory rabbits strains and their relationships, we applied DNA fingerprinting using bacteriophage M13 probe to five strains (2 inbreds (JWY-NIBS and DuY-NIBS) and 3 outbreds (JW-NIBS, Icl:JW and WHHL)). DNA fingerprints of 2 inbred strains showed the same banding patterns within each strain but the strain-specific patterns. Although there were no rabbits showing the same banding patterns in 3 outbred strains, average percent differences (APD) were 13.7 to 18.6. A dendrogram based on APD of DNA fingerprints was constructed by 2 large clusters, JW group and DuY. The dendrogram was essentially similar to that based on rabbit mandible measurements. These results suggest that DNA fingerprinting is available not only for the genetic monitoring of the laboratory rabbit strains but also for the investigation of their genetic relationships.

Animals↗
PubMed1993

Local cerebral blood flow and glucose metabolism in hydrostatic brain edema.

This study investigated the effect of hydrostatic pressure gradient on the cerebrovascular dynamics and metabolism during the development of brain edema. Hydrostatic brain edema was induced by bolus injection of autologous blood through the common carotid artery in Sprague-Dawley rats. Rats were divided into two groups, with craniectomy (Cr+ group) and without (Cr- group). Animals were sacrificed 0, 24, and 48 hours after hypertensive insult. Brain water content was determined by the gravimetric method. Regional cerebral blood flow and local cerebral glucose utilization were measured by the quantitative autoradiographic method using [14C]iodoantipyrine and [14C]deoxyglucose, respectively. Hypertensive insult produced multifocal lesions stained by Evans blue. Brains from the Cr- group showed a transient increase in water content and no significant change in cerebrovascular dynamics and metabolism. Brains from the Cr+ group showed a pronounced increase in water content which persisted 48 hours later. Misery perfusion was also observed 24 hours after the insult and the cerebrovascular dynamics and metabolism were significantly decreased after 48 hours. These results indicate that an increased hydrostatic pressure gradient enhances tissue damage and causes reopening of the blood-brain barrier.

Animals↗
PubMed1992

Synthesis and antitumor activity of 4'-O-acylanthracyclines.

4'-O-Acyl derivatives of doxorubicin, daunorubicin, 13-deoxocarminomycin, 13-deoxo-10-hydroxycarminomycin, 13-deoxo-11-deoxycarminomycin were synthesized through the formation and mild acid hydrolysis of 2-oxazoline intermediates. The antitumor activity of these 4'-O-acyl derivatives against P388 leukemia was similar to or more effective than the parent anthracyclines.

Animals↗