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Biomedical subjects

Y Uchida

Publications and source records attributed to Y Uchida.

At least 289 records · Page 16Linked to original sources
PubMed1996

[Effect of endoscopic sclerotherapy with esophageal varices on esophageal motility].

We investigated esophageal motility in 12 patients with esophageal varices by esophagography, scintigraphy and manometry before and after endoscopic sclerotherapy. In the manometric study, the appearance rates of the primary wave and the deglutitive relaxation decreased gradually after sclerotherapy, and the former improved within 3 months after discharge, while the latter tended to have a prolonged recovery period. The pressure of the lower esophageal sphincter was not significantly different before and after sclerotherapy. The length of the lower esophageal high pressure zone was greater than normal range before sclerotherapy, but it gradually shortened after sclerotherapy and improved by 3 months after sclerotherapy. The inducing rates of gastroesophageal reflux by abdominal compression was significantly higher at 3 months after sclerotherapy than before. In radiologic study, the esophageal transit time tended to prolong early after sclerotherapy, and it improved only slowly. We concluded that we need contrive to prevent from motility disorder of esophagus at the time of endoscopic sclerotherapy for patients with esophageal varices.

Adult↗
PubMed1996

Involvement of endothelins in immediate and late asthmatic responses of guinea pigs.

To explore the pathophysiological roles of endothelin isopeptides and receptor subtypes in asthmatic responses, a guinea pig model for asthma was used to test the effects of antiendothelin (ET) serum and selective ET receptor antagonists for antigen-induced specific airway conductance changes as measured by whole-body plethysmography. In this model, all of the animals so far tested demonstrated both the immediate and late asthmatic responses. Although preimmune serum had no apparent effects, anti-ET antiserum suppressed the maximal reduction of specific airway conductance in both the immediate and late asthmatic responses, which suggested that ET(s) are involved in the pathophysiology of both the immediate and late asthmatic responses. The ETB selective antagonists, BQ788 and RES701-1, blocked the immediate asthmatic response but not the late asthmatic response, whereas the ETA antagonists, BQ123 and (Shionogi) 97-139, suppressed only the late asthmatic response without influencing the immediate asthmatic response. In vitro constrictive responses of isolated tracheas and bronchi to ET1 were inhibited mainly by BQ123 and BQ788, respectively, which suggested that distribution of ETA and ETB receptors for bronchoconstriction are topographically distinct along airways. Furthermore, thromboxane A2 and platelet activating factor (PAF) antagonists were effective in suppressing the late asthmatic response but not the immediate asthmatic response. Taken together, our present observations suggest that ET(s) influences pulmonary functions by constricting airway smooth muscle via ETB receptors during the immediate asthmatic response and by modulating pulmonary inflammation via ETA receptors during the late asthmatic response, respectively.

Analysis of Variance↗
PubMed1996

[111In-labeled leukocyte scintigraphy in patients with inflammation of unknown focus].

This study evaluates the usefulness of 111In-labeled leukocyte scintigraphy to localize inflammatory foci that cannot be determined by clinical symptoms and other imaging studies. Patients with persistent fever following abdominal surgery (n = 20), suspected post-traumatic osteomyelitis associated with multiple fractures (n = 5), and fever of unknown origin (n = 22) were recruited. In all patients, the exact location of inflammatory foci could not be determined by clinical symptoms and conventional imaging studies. In patients with post-surgical fever, leukocyte scintigraphy localized responsible foci in 65% of patients and provided clinically useful information for the treatment. In patients with multiple fractures, the location of osteomyelitis was diagnosed confidently in only one case (20%). In patients with fever of unknown origin, responsible foci were detected in 18% of patients. Although in those patients positive leukocyte studies provided clinically useful information, overall usefulness seemed to be limited. Leukocyte scintigraphy is able to detect inflammatory foci in patients with post-surgical fever, but less likely to localize responsible foci for post-traumatic osteomyelitis or fever of unknown origin when patients have been examined carefully by clinical symptoms and conventional imaging studies.

Abdominal Abscess↗
PubMed1996

[A case of pulmonary dirofilariasis diagnosed through thoracoscopic lung biopsy].

A fifty-year-old man was admitted to our hospital for evaluation of an abnormal shadow in a routine chest X-ray film. Thorax CT scan revealed a relatively well defined nodule with a diameter 15 mm and pleural thickness in the posterior segment of the right lower lobe. A diagnosis by broncoscopy was undefinite and suspected to be a lung cancer. So thoracoscopic lung biopsy was performed to remove it. In a cross section of the resected nodule two degenerated worm structures were revealed and we diagnosed pulmonary dirofilariasis. Pulmonary dirofilariasis has been an increasing reported disease. Most of cases revealed a peripheral lung lesion. Thoracoscopic lung resection was useful for the diagnosis, considering as minimally invasive examination.

Animals↗
PubMed1996

[Surgical management of leak in an esophageal anastomosis].

The best management of anastomotic leaks is "prevention". In reconstruction of the esophagogastric anastomosis, special care should be taken to avoid injuring the vascular arcades between the right and left gastroepiploic arteries. Similarly in the colon interposition procedures, careful selection of the proper vascular pedicle is of basic importance, not only to avoid anastomotic leakage but to prevent gangrene of the conduit. If leakage occurs, initial management of small leaks includes decompression of the gastric tube or interposed colon pulled up, TPN and generally administration of antibiotics. For larger leaks, adequate drainage should be carried out and the necrotized, gastric tube or colonic segment should be removed immediately, and feeding jejiunostomy should be established. Free flap transfers of neovascularized jejunal segments were performed in three cases in our department with satisfactory postoperative course in order to repairer a chronic larger leaks (a partial defect of the gastric wall).

Anastomosis, Surgical↗
PubMed1996

Role of adenosine in blood flow in the rat intestine.

We examined the relation between adenosine production and increased blood flow. For this purpose, we used a sensor holding system with a laser Doppler blood flowmeter. The elevation of blood flow was observed by administration of adenosine. Therefore, when AMP was administered to the rats, the elevation of blood flow rate was observed. These results suggest that AMP is rapidly transported to the adenosine active site by ecto-5'-nucleotidase.

5'-Nucleotidase↗
PubMed1996

[Increased production of nitric oxide in the immediate and late asthmatic responses in guinea pigs].

The nitric oxide (NO) levels in exhaled air and the population of nitric oxide synthase (NOS) synthesizing epithelium in airways are reported to be increased in patients with asthma. NO may be implicated in the pathophysiology of asthma. In this study, we examined the inducible NOS (iNOS) mRNA levels in the lung of a guinea pig model of experimental asthma which exhibits both the immediate and late asthmatic responses (IAR/LAR), following challenge with antigen, using the methods of Northern blot analysis. After challenge with antigen, iNOS mRNA were increased in a time-dependent manner (before challenged < IAR < LAR). Furthermore, we estimated NO productions in the trachea using bioassay by 5-HT-induced tracheal smooth muscle relaxation which are involved in NO. The 5-HT-induced relaxations were accelerated in a time-dependent manner after challenge with antigen, reflecting increased NO production (before challenged < IAR < LAR). These observations suggest that NO would be involved in the pathophysiology of asthma.

Animals↗
PubMed1996

[A case of aortic dissection associated with congenital bicuspid aortic valve].

It is known that bicuspid aortic valve with dilatation of the ascending aorta is one of risk factors of the aortic dissection. A case of acute aortic dissection (DeBakey type-II) associated with bicuspid aortic valve who underwent successfully operation 8 hours after onset is reported. This patient went into cardiogenic shock because of cardiac tamponade and aortic valve regurgitation immediately after onset. Aortic valve and the ascending aorta were replaced using composite graft (#23 SJM prosthetic aortic valve and 26 mm woven Dacron vascular graft) combined with coronary artery reconstruction by Cabrol's technique. Aortic valve showed bicuspid and histological examination revealed cystic medionecrosis and loss of elastic fiber. Postoperative course was uneventful and this patients is doing well 3 years after the operation.

Acute Disease↗
PubMed1996

In vivo monitoring of .OH generation on jejunal ischemic injury by dialysis technique.

We applied an in vivo microdialysis technique to examine free radical generation following ischemic injury in the rat jejunum. For this purpose, we used a microdialysis probe holding system. The salicylate reacts with hydroxyl free radical (.OH) and generates 2,3-dihydroxybenzoic acid (DHBA), which can be measured electrochemically in picomole amounts by high-performance liquid chromatography (HPLC). Therefore, the former was used for trapping the .OH formation. Reperfusion of the jejunum produced progressive elevations in the levels of 2,3-DHBA achieving the maximums at 20 min, after which they decreased progressively to the baseline. These elevations were significant only after 10 min- and 20 min-ischemia. However, this change was not significant in the case of 30 min-ischemia. Ischemia-reperfusion of rat intestine caused morphological changes. These results suggest that .OH production is significantly reduced after 30 min-ischemia providing thus the possibility for more severe intestinal damage. In conclusion our dialysis probe can be useful for the measurement of .OH generation following ischemia-reperfusion injury.

Animals↗
PubMed1996

[Tumor imaging in nuclear medicine].

Tumor imaging in nuclear medicine has been improved by imaging instruments and newly developed radiopharmaceuticals. One of the imaging developments is a SPECT system using three-detector system. Its each detector rotates 120 degrees when SPECT projection data are acquired and we can save the scanning time and get a high resolution image which is less than 10 mm FWHM. About radiopharmaceuticals 99mTc MDP and 57Ga-citrate are used most commonly for detecting early metastatic lesions in the body. 201Tl chloride and 99mTc MIBI as used for cardiac imaging are also used for tumor detection. 111In-DTPA-D-Phe-octreotide are developed for detection of somatostatin receptor and will be used for many kinds of tumor such as small cell lung cancer, meningioma, malignant lymphoma and gastrointestinal hormone producing tumor.

Citric Acid↗
PubMed1995

Local treatment with antithrombotic drugs can prevent thrombus formation: an angioscopic and angiographic study.

OBJECTIVES: This study was designed to evaluate the efficacy of local versus systemic treatment of thrombosis with various antithrombotic drugs. BACKGROUND: Local use of low dose antithrombotic drugs has been proposed as being effective and safe. METHODS: Heparin (30 U/kg), an antithrombin agent (argatroban, 0.05 mg/kg body weight) or a defibrinogenating drug (batroxobin, 0.05 U/kg) was locally infused into one side of the canine iliac artery after injury by balloon inflation. The other side was injured as a control. The efficacy of systemic delivery of high dose (heparin [300 U/kg] and argatroban [0.5 mg/kg]) and low dose drugs was also assessed. RESULTS: Sixty minutes after local treatment in 22 dogs, no thrombotic stenosis was observed by angiography in locally treated arteries (p < 0.005 vs. mean thrombotic stenosis of 27% in control segments for heparin, 25.3% in control segments for argatroban and 32% in control segments for batroxobin). Angioscopy demonstrated the same trend. In locally treated arteries, thrombus weight was significantly lower in the treated than control side. In the systemic high dose group (n = 10), angiographic thrombotic stenosis was < 5% after high dose drug delivery (p < 0.05 vs. control segments, 37.4% for heparin, 43% for argatroban). In another 10 dogs, low dose systemic delivery was not effective in inhibiting thrombus formation. Activated partial thromboplastin time and fibrinogen levels did not change with local treatment. CONCLUSIONS: Compared with systemic administration of antithrombotic drugs, local treatment is a safer and more effective method of preventing thrombosis.

Angiography↗
PubMed1995

University of Wisconsin solution preserves myocardial calcium current response to isoproterenol in isolated canine ventricular myocytes.

BACKGROUND: University of Wisconsin (UW) solution has been shown to be an effective solution for cold storage of various organs. This study was designed to evaluate the subcellular protective mechanism of UW solution during cardiac myocyte storage using patch-clamp techniques for the first time as a tool for the detection of myocyte viability. METHODS AND RESULTS: The protective effects of UW solution on the preservation of dihydropyridine-sensitive Ca2+ channel current response to catecholamine were evaluated in canine cardiac ventricular cells by measurement of single channel open probability. Single ventricular myocytes were isolated and stored in UW solution, in Stanford (SF) solution, or in St Thomas' (ST) solution at 4 degrees C for 2, 6, 12, and 24 hours, and after each storage period, recordings were made of cell-attached single Ca2+ channel currents. When 0.1 mumol/L isoproterenol was applied, percent mean open probability of the Ca2+ channel tested in freshly isolated cells was 167 +/- 4% (n = 24) of controls (100%). The response was decrescent with increased duration of the hypothermic storage and was only 130 +/- 12% (n = 4) after 24 hours of storage in SF solution and 135 +/- 9% (n = 7) in ST solution. However, it was significantly highly preserved as much as 165 +/- 9% (n = 6) in UW solution. Ca2+ channel kinetics and channel conductance were not changed after up to 24 hours of hypothermic storage. CONCLUSIONS: Hypothermic storage of canine cardiac myocytes in UW solution preserved beta-adrenergic response, which suggests that UW solution during cold storage preserved high-energy phosphates in myocytes that are responsible for Ca2+ channel phosphorylations.

Adenosine↗
PubMed1995

Endothelin-1, but not endothelin-3, suppresses lipoprotein lipase gene expression in brown adipocytes differentiated in culture.

The effect of endothelins on lipoprotein lipase activity and lipoprotein lipase mRNA levels was studied in brown adipocytes differentiated in culture. Lipoprotein lipase activity was determined in two fractions; lipoprotein lipase released by heparin (10 IU/ml, 1 h) into the medium (heparin-releasable fraction) and lipoprotein lipase activity remaining in cells (extractable fraction). Time-course studies showed that endothelin 1 (10(-7) M) progressively decreased both lipoprotein lipase fractions (heparin-releasable, extractable), until nadir at 24 h. Endothelin-1 reduced both lipoprotein lipase activities (heparin-releasable, extractable) in a concentration-dependent manner, whereas endothelin-3 did not produce any significant changes in either of them. Northern blot analysis revealed that endothelin-1 (10(-7)-10(-11) M) caused a concentration-dependent decrease in lipoprotein lipase mRNA obtained from cells on day 9. Furthermore, pretreatment of brown adipocytes with endothelin ETA receptor antagonist FR139317 antagonized the endothelin-1-induced reduction of lipoprotein lipase activity and lipoprotein lipase mRNA. These results suggest that endothelin-1 decreases lipoprotein lipase activity by inhibiting the lipoprotein lipase gene expression in brown adipocytes differentiated in culture, possibly through endothelin ETA receptors on cell membranes. Because of marked reduction of lipoprotein lipase activity and its mRNA as a marker of adipogenic differentiation, endothelin-1 may have an inhibitory role in the differentiation of brown adipocytes.

Adipocytes↗
PubMed1995

Blood flow rate in jejunal ischemia-reperfusion injury.

We examined changes in the blood flow rate in the course of jejunal ischemic injury using a laser Doppler flowmeter. For this purpose, we designed a sensor holding system, which involved the fixation of the sensor to the jejunum and allowed their movements to be synchronized. When the jejunum was reperfused after 10 min of ischemia, the blood flow rate markedly increased and then gradually decreased to the initial level. A 30-min period of ischemia produced the slowest recovery of the blood flow rate. This system could be useful for monitoring the blood flow rate in different anatomical regions.

Animals↗
PubMed1995

Changes of growth inhibitory factor after stab wounds in rat brain.

The growth inhibitory factor (GIF) is a new metallothionein (MT)-like protein that is downregulated in Alzheimer's disease (AD) brain. The biological function of GIF has not been fully clarified yet. We have raised an antibody to the synthetic polypeptide that is specific for rat GIF. The purified antibody reacted to recombinant GIF and native rat GIF but not to MT or maltose-binding protein. Using the antibody and GIF cDNA probe, we investigated changes of GIF and GIF mRNA by Western and Northern blotting techniques in rat brains after stab wounds. The levels of GIF and GIF mRNA began to increase 4 days postoperation, reached a maximum at 14-21 days and sustained the increased level at least through 28 days. While both glial fibrillary acidic protein (GFAP) and GIF were recognized in astrocytes, the increases of these 2 proteins after stab wounds showed different patterns. The results indicated that GIF could play an important role in the repair after brain damage and also produce new insights into the mechanism of gliosis investigated mainly from the viewpoint of GFAP.

Alzheimer Disease↗
PubMed1995

Characterization of chitin synthase 2 of Saccharomyces cerevisiae. Implication of two highly conserved domains as possible catalytic sites.

Chitin synthase 2 of Saccharomyces cerevisiae was characterized by means of site-directed mutagenesis and subsequent expression of the mutant enzymes in yeast cells. Chitin synthase 2 shares a region whose sequence is highly conserved in all chitin synthases. Substitutions of conserved amino acids in this region with alanine (alanine scanning) identified two domains in which any conserved amino acid could not be replaced by alanine to retain enzyme activity. These two domains contained unique sequences, Glu561-Asp562-Arg563 and Gln601-Arg602-Arg603-Arg604-Trp605, that were conserved in all types of chitin synthases. Glu561 or arginine at 563, 602, and 603 could be substituted by glutamic acid and lysine, respectively, without significant loss of enzyme activity. However, even conservative substitutions of Asp562 with glutamic acid, Gln601 with asparagine, Arg604 with lysine, or Trp605 with tyrosine drastically decreased the activity, but did not affect apparent Km values for the substrate significantly. In addition to these amino acids, Asp441 was also found in all chitin synthase. The mutant harboring a glutamic acid substitution for Asp441 severely lost activity, but it showed a similar apparent Km value for the substrate. Amounts of the mutant enzymes in total membranes were more or less the same as found in the wild type. Furthermore, Asp441, Asp562, Gln601, Arg604, and Trp605 are completely conserved in other proteins possessing N-acetylglucosaminyltransferase activity such as NodC proteins of Rhizobium bacterias. These results suggest that Asp441, Asp562, Gln601, Arg604, and Trp605 are located in the active pocket and that they function as the catalytic residues of the enzyme.

Amino Acid Sequence↗