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Biomedical subjects

Y Moriyama

Publications and source records attributed to Y Moriyama.

At least 37 records · Page 2Linked to original sources
PubMed2001

The relationship of left ventricular mass to endothelium-dependent vasodilation of the brachial artery in patients with hypertension.

Although echocardiographically determined left ventricular mass and geometry predict cardiovascular morbid events in patients with hypertension, the mechanisms underlying this relation are unclear. There is considerable evidence that endothelium-dependent vasodilation is impaired in patients with hypertension. Thus, endothelial dysfunction may contribute to the mechanism that causes cardiovascular morbid events. This study was designed to examine the relationship between left ventricular geometry and endothelial function in patients with hypertension. The percentage increase in brachial arterial diameter during reactive hyperemia was examined by a high-resolution ultrasound technique in 49 patients with hypertension and 64 normotensive subjects. Patients with hypertension had an impairment of the percentage increase in brachial arterial diameter during reactive hyperemia and an increase in thiobarbituric acid-reactive substances (TBARS) compared to normotensive subjects (percentage increase in diameter 5.6 +/- 3.0 vs. 8.0 +/- 2.5%, p < 0.001; TBARS levels 6.1 +/- 1.3 vs. 5.3 +/- 1.0 nmol/ml, p < 0.001). In patients with hypertension, there was a significant correlation between the left ventricular mass index and the percentage increase in brachial arterial diameter during reactive hyperemia (r = -0.583, p < 0.001), and the percentage increase in brachial arterial diameter during reactive hyperemia varied with the pattern of left ventricular geometry (normal ventricular geometry: 7.7 +/- 2.6%; concentric remodeling: 5.2 +/- 2.3%; eccentric hypertrophy: 4.2 +/- 1.8%; concentric hypertrophy: 2.9 +/- 2.6%). We conclude that (1) flow-mediated endothelium-dependent vasodilation in the brachial artery is impaired in patients with hypertension, (2) a relationship exists between the left ventricular mass index and flow-mediated endothelium-dependent vasodilation in the brachial artery in patients with hypertension and (3) increased oxidative stress may play a role in the endothelial dysfunction in patients with hypertension.

Adult↗
PubMed2001

Possible remediation of dioxin-polluted soil by steam distillation.

2,7-Dichlorodibenzo-p-dioxin (DCDD) was found to evaporate easily with water vapor from a heated solution. Steam distillation was also effective for the removal of DCDD from DCDD-applied soil; its concentration (250 microg/50g soil) in the original soil decreased to less than 5% after steam distillation for only 20 min. Actual dioxin-polluted soil in Tokorozawa City was partially decontaminated using the same method. These results suggest that steam distillation could be a new remedial method for soils contaminated with persistent environmental pollutants, such as dioxins and polychlorinated biphenyls.

Decontamination↗
PubMed2001

Application of combined reagent solution to the oxidative refolding of recombinant human interleukin 6.

Human interleukin 6 (hIL-6), which is a cytokine involved in diverse biological activities, consists of a four-helix bundle with two disulfide bonds. For the clinical use of hIL-6 in cancer therapy, designing of commercial-scale production systems of recombinant hIL-6 (rhIL-6) expressed by E. coli has been attempted. Since rhIL-6 has been produced as inclusion bodies in the expression systems reported to date, establishment of a strategy to achieve a high yield of refolding of this recombinant protein is quite desirable. It has been reported that oxidation of rhIL-6 under a completely denaturing condition suppresses aggregation during the refolding process [Ejima et al., Biotechnol. Bioeng., 62, 301-310 (1999)]. In this protocol, however, small but significant amounts of unidentified by-products unavoidably arose, which might be problematic in the therapeutic use of rhIL-6. In the present study, detailed characterization of the individual by-products has been performed on inspection of peptide maps, and the by-products found to originate from improperly formed disulfide bonds, most of which are disulfide-linked dimers. In order to minimize these by-products, combined solutions of urea and LiCl were used for oxidative refolding of rhIL-6. It was demonstrated that combined use of 1-2 M urea and 1-3 M LiCl effectively suppresses the formation of the by-products as well as aggregates. We propose that the use of the combined reagents can be an alternative method for refolding of rhIL-6 for clinical purposes.

Chromatography, High Pressure Liquid↗
PubMed2001

Combined revascularization strategy for acute myocardial infarction in patients with intracoronary thrombus: preceding intracoronary thrombolysis and subsequent mechanical angioplasty.

Thrombus in the infarct-related artery is one of the limitations for flow restoration in primary percutaneous transluminal coronary angioplasty (PTCA) treatment for acute myocardial infarction (AMI). The present study investigated the benefit of preceding intracoronary thrombolysis (ICT) by retrospectively analyzing acute phase flow restoration in 80 AMI patients with intracoronary thrombus: 40 undergoing primary PTCA alone (primary PTCA group) and 40 treated with preceding ICT plus PTCA (combined group). Acute phase Thrombolysis in Myocardial Infarction (TIMI) grade flow was as follows: TIMI 0/1: 35.0% vs 12.5% for the primary PTCA group and the combined group, p=0.06; TIMI 2: 7.5% vs 15.0%, p=NS; TIMI 3: 57.5% vs 72.5%, p=NS). In the subgroup analysis, it was also less in the combined group among 33 patients with a left anterior descending coronary artery (LAD) lesion (42.1 % vs 7.1%, p=0.08), but not among the remaining 47 with either a right coronary artery or left circumflex artery lesion. The combined therapy may potentially provide better acute phase flow restoration in AMI patients with an intracoronary thrombus in a LAD lesion.

Aged↗
PubMed2001

Nitric oxide-mediated vasodilatation is decreased in forearm resistance vessels in patients with coronary spastic angina.

It has been reported that coronary endothelial dysfunction is associated with the pathogenesis of coronary spasm, and that endothelial nitric oxide (NO) mediated vasodilatation was decreased in coronary epicardial arteries in patients with coronary spastic angina (CSA). However, there are few reports about the endothelial function in peripheral resistance vessels of patients with CSA, so the present study investigated the role of NO in forearm resistance vessels in such patients. The responses of forearm blood flow to acetylcholine (ACh; 8-24 microg/min) and sodium nitroprusside (SNP; 0.4-1.2 microg/ml) infusions was examined using plethysmography, and subsequently the responses to ACh after an infusion of N(G)-monomethyl-L-arginine (L-NMMA; 4 micromol/min, for 5 min) in 17 patients with CSA and 17 age- and sex- matched controls. The vasodilator responses to ACh and SNP were comparable between the 2 groups (p=NS). L-NMMA significantly suppressed the vasodilator responses to ACh in controls (p<0.05), but there was no significant difference in the responses to ACh before and after infusion of L-NMMA in patients with CSA (p=NS). These results indicate that endothelial NO-mediated vasodilatation is decreased in the forearm resistance vessels of patients with CSA.

Acetylcholine↗
PubMed2001

[Pharmacological and therapeutic properties of lafutidine (stogar and protecadin), a novel histamine H2 receptor antagonist with gastroprotective activity].

Potent antisecretory agents, such as histamine H2-receptor antagonists and proton pump inhibitors, have achieved great improvement in peptic ulcer therapy. It has, however, been reported that incidence of ulcer relapse is high after discontinuation of these drugs. Insufficient efficacy against NSAID-induced ulcers is also critical. Lafutidine is a novel histamine H2 antagonist with gastroprotective activity. Lafutidine exhibited potent and long-lasting H2 antagonism and prolonged antisecretion. In addition, lafutidine showed a gastroprotective effect against noxious agents-induced gastric mucosal damage through capsaicin-sensitive afferent nerves. Lafutidine showed antiulcer activities against acute ulcer models, prevented gastric ulcer relapse of acetic ulcer, and accelerated the healing of indomethacin-induced antral ulcers in rats. These results suggest the advantage of the combined antisecretory and gastroprotective activities. In clinical studies, lafutidine showed prolonged antisecretion, healing effect against gastric and duodenal ulcers and gastritis, and its potency was equal or superior to that of conventional H2 antagonists. Additionally, lafutidine induced a high transition rate to the E0 stage determined by endoscopical ultrasonography, suggesting the high quality of ulcer healing. Furthermore, effectiveness of lafutidine against NSAIDs-induced ulcer was high. From these results, lafutidine is equal or superior to conventional H2 antagonists in antiulcer potency, and it may be useful for the prevention of ulcer relapse and or treatment of NSAIDs-induced gastroduodenal damage.

Acetamides↗
PubMed2001

Ca2+-dependent exocytosis of L-glutamate by alphaTC6, clonal mouse pancreatic alpha-cells.

Pancreatic islet cells express receptors and transporters for L-glutamate and are thus believed to use L-glutamate as an intercellular signaling molecule. However, the mechanism by which L-glutamate appears in the islets is unknown. In the present study, we investigated whether L-glutamate is secreted through exocytosis by alphaTC6 cells (clonal mouse pancreatic alpha-cells). An appreciable amount of L-glutamate was released from cultured cells after the addition of KCl or A23187 in the presence of Ca2+ and 10 mmol/l glucose in the medium. The KCl-induced glutamate release was significantly reduced when assayed in the absence of Ca2+ or when the cells were pretreated with EGTA-AM. The KCl-induced Ca2+-dependent glutamate release was inhibited approximately 40% by voltage-gated Ca2+ channel blockers, such as nifedipine at 20 micromol/l. The degree of KCl-induced Ca2+-dependent glutamate release was correlated with an increase in intracellular [Ca2+], as monitored by fura-2 fluorescence. Botulinum neurotoxin type E inhibited 55% of the KCl-induced Ca2+-dependent glutamate release, followed by specific cleavage of 25 kDa synaptosomal-associated protein. Furthermore, bafilomycin A1, a specific inhibitor of vacuolar H+-ATPase, inhibited 40% of the KCl-induced Ca2+-dependent glutamate release. Immunoelectronmicroscopy with antibodies against synaptophysin, a marker for neuronal synaptic vesicles and endocrine synaptic-like microvesicles, revealed a large number of synaptophysin-positive clear vesicles in cells. Digitonin-permeabilized cells took up L-glutamate only in the presence of MgATP, which is sensitive to bafilomycin A1 or 3,5-di-tert-butyl-4-hydroxybenzylidene-malononitrile (a proton conductor) but insensitive to either oligomycin or vanadate. From these results, it was concluded that alphaTC6 cells accumulate L-glutamate in the synaptophysin-containing vesicles in an ATP-dependent manner and secrete it through a Ca2+-dependent exocytic mechanism. The Ca2+-dependent glutamate release was also triggered when cells were transferred in the medium containing 1 mmol/l glucose, suggesting that low glucose treatment stimulates the release of glutamate. Our results are consistent with the idea that L-glutamate is secreted by alpha-cells through Ca2+-dependent regulated exocytosis.

Adenosine Triphosphate↗
PubMed2001

Increased plasminogen activator inhibitor activity and diabetes predict subsequent coronary events in patients with angina pectoris.

BACKGROUND: Plasminogen activator inhibitor (PAI) is a marker of recurrence of myocardial infarction. Diabetes mellitus is also an important risk factor of coronary artery disease, including myocardial infarction and angina pectoris. AIM: We examined baseline plasma PAI activity levels, clinical variables, and angiographic findings and assessed them as prospective values for subsequent coronary events, such as sudden death, nonfatal myocardial infarction and coronary revascularization by percutaneous transluminal coronary angioplasty or coronary artery bypass surgery during the follow-up period. METHODS: We conducted a prospective study for 4 years of 249 consecutive patients admitted with angina pectoris. Blood samples for PAI were drawn at discharge. RESULTS: In the multivariate Cox proportional hazard model, PAI activity and diabetes mellitus were significant and independent risk factors (the risk increased by 10% in those with a higher PAI concentration and by 70% in diabetic patients). Event-free survival was reduced by higher PAI activity (> or = 8.4 IU/mL) and the presence of diabetes. The patients with higher PAI activity and diabetes had a 4.2-fold risk in comparison with the patients with lower PAI activity and no diabetes. However, patients with lower PAI activity were less likely to have coronary events even when they had diabetes. CONCLUSIONS: Higher PAI activity and diabetes predict subsequent coronary events in patients with angina pectoris. Diabetes has less prognostic value for subsequent coronary events in patients with lower PAI activity.

Angina Pectoris↗
PubMed2001

[Experience of four cases of postoperative pulmonary embolism requiring surgical treatment].

Four patients underwent a pulmonary embolectomy using cardiopulmonary bypass for acute pulmonary embolism which had occurred after various operations. In two cases, dehydration due to either diabetes insipidus or ileus had existed. In two cases, pulmonary embolism suddenly occurred in our hospital. In the remainder, the disease occurred in the previous hospitals and its diagnosis was established on the 6th and 7th postoperative days, respectively. In massive pulmonary embolism, echocardiography and/or enhanced chest CT are useful for prompt and noninvasive diagnosis. Thrombolytic therapy was performed in only one case before surgical embolectomy, which was not effective. Three patients were discharged without any postoperative complications, but one requiring preoperative external cardiac massage died of multiple organ failure 9 days after operation. Acute pulmonary embolism is one of the fatal postoperative complications. Recognition of this entity, and prompt diagnosis and treatment are essential for managing the fatal disease. Even in the early postoperative period, embolectomy using cardiopulmonary bypass is a safe and effective treatment.

Acute Disease↗
PubMed2001

Tumor-suppressor effect of interferon regulatory factor-1 in human hepatocellular carcinoma.

IFN regulatory factor-1 (IRF-1) regulates the IFN system, inhibits cell growth, and has tumor-suppressor activities. p21 is a universal cyclin-dependent kinase inhibitor, the induction of which depends on both p53 and IRF-1 in mouse embryonic fibroblasts. The expression of p21 in hepatocellular carcinomas (HCCs) is regulated by wild-type p53. We examined the expressions of IRF-1 and p21 in 32 HCCs by quantitative reverse transcription-PCR and the mutation p53 gene in 32 HCCs by single-strand conformation polymorphism and direct sequencing. The expression of IRF-1 mRNA in 15 of 32 HCCs was lower than that in adjacent noncancerous tissue. IRF-1 mRNA expression was reduced in 0 of 3 specimens of well-differentiated HCC, 9 of 21 (42%) specimens of moderately differentiated HCC, and 6 of 8 (75%) specimens of poorly differentiated HCC. IRF-1 mRNA expression was significantly lower in tumors with portal thrombus than in those without portal thrombus (P = 0.003). p53 mutations were detected in 7 of 32 HCCS: p21 expression was reduced in 6 of the 7 (86%) HCCs with p53 mutations. In contrast, p21 expression was reduced in 13 of 25 (52%) HCCs with wild-type p53. IRF-1 expression was reduced in 7 of 13 (53%) HCCs with both wild-type p53 and reduced expression of p21. These results suggest that IRF-1 may be a tumor-suppressor gene for HCC and that IRF-1 is related to p21 expression in HCC with wild-type p53.

Aged↗
PubMed2001

Double left renal vein associated with abdominal aortic aneurysm.

Double left renal vein is a rare venous anomaly. We operated on 72-year-old man of abdominal aortic aneurysm (AAA) with double left renal vein. Massive hemorrhage was encountered during encircling the tape around the abdominal aorta. One vein passing posterior to the aorta was injured. Further dissection revealed the presence of double left renal vein forming a ring around the aorta. The patient underwent an abdominal aortic replacement following prompt repair of the injured vein. He had an uneventful postoperative course without renal complication. We missed that preoperative computed tomographic (CT) scan had demonstrated double left renal vein. Preoperative contrast-enhanced CT scan is useful and essential not only for evaluation of AAA, but also for establishing the presence of venous anomalies. Venous anomalies should be taken into consideration on the AAA operation.

Aged↗
PubMed2000

Ionotropic glutamate receptors expressed in human retinoblastoma Y79 cells.

Mammalian retinal photoreceptors and pinealocytes have common characteristic that they secrete melatonin and L-glutamate as chemical transmitters. Although pinealocytes express glutamate receptors and receive glutamate signals, whether or not photoreceptors express glutamate receptors is unknown. Here, we investigated the expression of the glutamate receptors in cultured Y79 clonal human retinoblastoma cells, as model systems of photoreceptors. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that GluR1, GluR5, GluR7, EAA2, NR1, NR2A and NR2D mRNAs were present in the cultured cells. Northern analysis confirmed the presence of GluR7, EAA2, NR1, NR2A and NR2D mRNAs, while other mRNAs were under the detection limit. Addition of (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid or kainate increases intracellular (Ca(2+)) in Fura-2 loaded cells, which is blocked by 6-cyano-7-nitroquinoxaline-2,3-dione. N-methyl-D-aspartate also increases intracellular (Ca(2+)). These results demonstrated the presence of functional ionotropic receptors in Y79 cells.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2000

Vacuolar H(+)-ATPase localized in plasma membranes of malaria parasite cells, Plasmodium falciparum, is involved in regional acidification of parasitized erythrocytes.

Recent biochemical studies involving 2',7'-bis-(2-carboxyethyl)-5, 6-carboxylfluorescein (BCECF)-labeled saponin-permeabilized and parasitized erythrocytes indicated that malaria parasite cells maintain the resting cytoplasmic pH at about 7.3, and treatment with vacuolar proton-pump inhibitors reduces the resting pH to 6.7, suggesting proton extrusion from the parasite cells via vacuolar H(+)-ATPase (Saliba, K. J., and Kirk, K. (1999) J. Biol. Chem. 274, 33213-33219). In the present study, we investigated the localization of vacuolar H(+)-ATPase in Plasmodium falciparum cells infecting erythrocytes. Antibodies against vacuolar H(+)-ATPase subunit A and B specifically immunostained the infecting parasite cells and recognized a single 67- and 55-kDa polypeptide, respectively. Immunoelectron microscopy indicated that the immunological counterpart of V-ATPase subunits A and B is localized at the plasma membrane, small clear vesicles, and food vacuoles, a lower extent being detected at the parasitophorus vacuolar membrane of the parasite cells. We measured the cytoplasmic pH of both infected erythrocytes and invading malaria parasite cells by microfluorimetry using BCECF fluorescence. It was found that a restricted area of the erythrocyte cytoplasm near a parasite cell is slightly acidic, being about pH 6.9. The pH increased to pH 7.3 upon the addition of either concanamycin B or bafilomycin A(1), specific inhibitors of vacuolar H(+)-ATPase. Simultaneously, the cytoplasmic pH of the infecting parasite cell decreased from pH 7.3 to 7.1. Neither vanadate at 0.5 mm, an inhibitor of P-type H(+)-ATPase, nor ethylisopropylamiloride at 0.2 mm, an inhibitor of Na(+)/H(+)-exchanger, affected the cytoplasmic pH of erythrocytes or infecting parasite cells. These results constitute direct evidence that plasma membrane vacuolar H(+)-ATPase is responsible for active extrusion of protons from the parasite cells.

Acids↗
PubMed2000

Beneficial effect of additional cardioplegia flush during hypothermic static cardiac preservation.

BACKGROUND: The effects of various preservative solutions and methods have been studied to prolong the safety period of cardiac preservation. In this study, we used cardioplegic solution (CS) during cardiac preservation and investigated how flush CS yields good preservation of isolated hearts compared with only cold immersion. METHODS: Male Wistar rat hearts were arrested with 4 degrees C St. Thomas crystalloid CS. All hearts were immersed for 6 hr in a 4 degrees C Euro-Collins solution. Hearts were classified into seven groups by period and number of infusions of CS (20 ml/kg) during simple immersion of hearts. Infusion of CS during preservation was not used for group I. Infusion was performed at two hours after starting immersion for group II, at 3 hr for group III, at 4 hr for group IV, at 5 hr for group V, every hour for group VI, and every 2 hr for group VII. After preservation, the hearts were reperfused with blood using a support rat. Myocardial adenosine triphosphate was measured immediately after immersion of hearts. Biochemical examination of coronary effluents was performed at 15 min after reperfusion, and cardiac function was evaluated at 40 min after reperfusion. Myocardial specimens were subsequently taken for measurement of water content. RESULTS: Percentage recovery of left ventricular developed pressure and dp/dt in groups III, VI, and VII were higher than those in group I at each balloon volume, and left ventricular end-diastolic pressure in these groups was also significantly lower than that in group I. Levels of creatine kinase-MB and lactate in groups VI and VII after reperfusion were significantly lower than those in group I. Myocardial adenosine triphosphate was significantly better preserved in groups III, IV, VI, and VII than in group I. However, no significant difference in cardiac function or myocardial adenosine triphosphate was found among groups III, IV, VI, and VII. CONCLUSIONS: The use of CS during cardiac preservation is effective in preserving cardiac function and myocardial enzymes, and infusion may be sufficient if performed once-only at 3 or 4 hr from starting immersion in 6 hr storage of isolated rat hearts.

Adenosine Triphosphate↗
PubMed2000

Intra- and intermolecular interactions of the catalytic domains of human CD45 protein tyrosine phosphatase.

We have investigated protein-protein interaction between distinct domains of the human CD45 cytoplasmic region using a yeast two-hybrid system. Consequently, we have found that the spacer region between two tandem PTP domains specifically interacts with the membrane-distal PTP domain (D2). This interaction is mediated by a stretch of amino acid residues in the carboxyl-terminal half of the spacer region. Although the membrane proximal region does not directly interact with either of the two PTP domains, it appears to function in stabilizing the interaction between the spacer region and D2. We also demonstrate that the interaction between the spacer region and D2 might take place intramolecularly.

Catalytic Domain↗
PubMed2000

Papillary fibroelastoma on the mitral valve.

A 78-year-old woman was admitted with transient unknown fever and old cerebral infarction. An echocardiogram demonstrated mild mitral valve regurgitation and high echogenic mass on the mitral posterior leaflet. Surgery was performed with the diagnosis of a healed infective endocarditis. A sea anemone-like appearance tumor, 8 mm in diameter, was located on the mitral posterior leaflet. Annuloplasty was performed following removal of the tumor. A pathological examination confirmed the lesion was a papillary fibroelastoma. No evidence of infective endocarditis was seen. The cause of the fever remained unknown. The tumor was very fragile. Surgical removal was mandatory for preventing embolism despite the advanced age.

Aged↗