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H Isobe

Publications and source records attributed to H Isobe.

At least 19 recordsLinked to original sources
PubMed1999

Nonstatistical binding of a protein to clustered carbohydrates.

Carbohydrate-derivatized self-assembled monolayers (SAMs) are used as a model system to address issues involving cell-surface carbohydrate-protein interactions. Here we examine the influence of carbohydrate surface density on protein-binding avidity. We show that the binding selectivity of Bauhinia purpurea lectin switches from one carbohydrate ligand to another as the surface density of the carbohydrate ligands increases from values of chi(sugar) approximately 0.1-1.0. Polyvalent binding is possible at all surface densities investigated; hence, the switch in selectivity is not due simply to the achievement of a critical density that permits polyvalent contacts. Instead, secondary interactions at high surface densities promote a switch in carbohydrate-binding selectivity. These findings may have implications for how changes in the composition and the density of cell-surface carbohydrates influence biological recognition processes and regulatory pathways.

Carbohydrate Metabolism↗
PubMed1999

Porous Silica Particles Prepared from Silicon Tetrachloride Using Ultrasonic Spray Method.

Silica particles having the median diameter of 1 to 3 µm were prepared from silicon tetrachloride vapor by a reaction with water droplets using the ultrasonic spray method. The particle sizes of silicas were controlled by changing the composition of silicon tetrachloride and water. These silica particles had microporous structures from nitrogen and water adsorption measurements. The microporous and mesoporous particles were prepared from the reaction of water droplets including sodium and potassium carbonates with silicon tetrachloride vapor. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Antithrombin reduces ischemia/reperfusion injury of rat liver by increasing the hepatic level of prostacyclin.

We investigated whether antithrombin (AT) can reduce ischemia/reperfusion (I/R)-induced injury of rat liver by promoting prostacyclin release from endothelial cells. Although intravenous administration of AT (250 U/kg) markedly reduced hepatic injury, neither dansyl-Glu-Gly-Arg-chloromethyl ketone-treated factor Xa (DEGR-Xa), a selective inhibitor of thrombin generation, nor Trp49-modified AT, which lacks affinity for heparin, had any effect. Hepatic levels of 6-keto-PGF1, a stable prostacyclin (PGI2) metabolite, were increased significantly after I/R of the rat liver. AT significantly increased the hepatic level of 6-keto-PGF1, whereas neither DEGR-Xa nor Trp49-modified AT increased it. Hepatic tissue blood flow was markedly reduced after I/R. Although AT significantly increased the hepatic tissue blood flow after I/R, neither DEGR-Xa nor Trp49-modified AT increased the blood flow. Hepatic levels of cytokine-induced neutrophil chemoattractant (CINC) and myeloperoxidase (MPO) were significantly increased after hepatic I/R. The levels of these two indicators were reduced by AT but were unaffected by either DEGR-Xa or Trp49-modified AT. Pretreatment of animals with indomethacin (IM) completely inhibited the protective effects of AT on the I/R-induced hepatic damage and the leukocyte activation as well as the AT-induced increase in hepatic 6-keto-PGF1 levels after I/R. Iloprost, a stable analog of PGI2, exhibited effects similar to those of AT and also significantly inhibited the exacerbation of liver injury, the decrease in hepatic tissue blood flow, and the increases in hepatic CINC and MPO levels seen in rats subjected to I/R but pretreated with IM. These findings suggest that AT may prevent I/R-induced hepatic injury by increasing the hepatic levels of PGI2 through the interaction of AT with cell-surface glycosaminoglycans, thus increasing hepatic tissue blood flow and inhibiting leukocyte activation in animals subjected to I/R.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Antithrombin prevents stress-induced gastric mucosal injury by increasing the gastric prostacyclin level in rats.

The interaction of antithrombin (AT) with cell surface glycosaminoglycans has been shown to promote the endothelial release of prostacyclin (PGI2). Because PGI2 plays an important role in gastric cytoprotection, we examined whether AT prevents water-immersion restraint stress (WIR)-induced gastric mucosal injury in rats by promoting the endothelial release of PGI2. Intravenous administration of AT (250 U/kg) prevented WIR-induced gastric mucosal injury in rats. Gastric levels of 6-keto-prostaglandin F1alpha, a stable metabolite of PGI2, were significantly increased 0.5 and 1 hour after WIR in animals administered AT compared with control animals. The effects induced by AT in animals subjected to WIR were not observed in animals that were administered DEGR-Xa, a selective inhibitor of thrombin generation, or Trp49-modified AT, which lacks affinity for heparin. In animals subjected to WIR gastric mucosal blood flow was significantly reduced with a simultaneous increase in gastric mucosal microvascular permeability. Activated neutrophils have been implicated in the WIR-induced reduction of gastric mucosal blood flow by increasing microvascular permeability. Although AT prevented the reduction of gastric mucosal blood flow and the increase in gastric mucosal microvascular permeability in animals subjected to WIR, neither DEGR-Xa nor Trp49-modified AT had any effect. Pretreatment of animals with indomethacin completely inhibited the protective effects of AT against WIR-induced gastric mucosal injury and the AT-induced increase in post-WIR gastric 6-keto-prostaglandin F1alpha levels. These results strongly suggest that AT prevents stress-induced gastric mucosal injury by increasing the gastric levels of PGI2 through the interaction of AT with cell-surface glycosaminoglycans, thus increasing gastric mucosal blood flow both by vasodilation and by inhibiting neutrophil activation.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Gastric prostacyclin (PGI2) prevents stress-induced gastric mucosal injury in rats primarily by inhibiting leukocyte activation.

We investigated whether, in rats, gastric prostacyclin (PGI2) prevented gastric mucosal injury that was induced by water-immersion restraint stress by inhibiting leukocyte activation. Gastric levels of 6-keto-PGF1alpha, a stable metabolite of PGI2, increased transiently 30 min after stress, followed by a decrease to below the baseline 6-8 h after stress. Gastric mucosal blood flow decreased to approximately 40% of the baseline level 8 h after stress. Myeloperoxidase activity was significantly increased 8 h after stress. Treatment with indomethacin before stress inhibited the increase in 6-keto-PGF1alpha levels and markedly reduced mucosal blood flow. It also markedly increased leukocyte accumulation and mucosal lesion formation. Iloprost, a stable PGI2 analog, inhibited the indomethacin-induced decrease in mucosal blood flow, mucosal lesion exacerbation, and increase in leukocyte accumulation. Nitrogen mustard-induced leukocytopenia inhibited the indomethacin-associated lesion exacerbation and the increase in leukocyte accumulation, but not the decreases in mucosal blood flow. These observations indicate that gastric PGI2 decreases gastric mucosal lesion formation primarily by inhibiting leukocyte accumulation.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Plaunotol prevents indomethacin-induced gastric mucosal injury in rats by inhibiting neutrophil activation.

BACKGROUND: Activated neutrophils play a critical role in indomethacin-induced gastric mucosal injury. AIM: To investigate the effect of plaunotol, an anti-ulcer agent, on neutrophil activation in vitro and its effect on gastric mucosal injury and gastric accumulation of neutrophils in rats given indomethacin. METHODS: Human monocytes and neutrophils were isolated from the peripheral blood of healthy volunteers. We examined the effect of plaunotol on neutrophil elastase release, production of O2-, intracellular calcium concentration and expression of adhesion molecules CD11b and CD18 in activated neutrophils in vitro. The effect of plaunotol on TNF-alpha production by monocytes stimulated with endotoxin also was investigated in vitro. The effect of plaunotol (100 mg/kg, p.o.) on gastric mucosal injury and neutrophil accumulation was investigated in male Wistar rats given indomethacin (30 mg/kg, p.o.). RESULTS: Plaunotol inhibited the fMLP-induced release of neutrophil elastase from activated neutrophils, as well as the opsonized zymosan-induced production of O2- by neutrophils. Plaunotol significantly inhibited increased levels of intracellular calcium, a second messenger of neutrophil activation, in vitro. The fMLP-induced increases in CD11b and CD18 expression were also inhibited by plaunotol in vitro. Plaunotol inhibited monocytic production of TNF-alpha, a potent activator of neutrophils. Both gastric mucosal injury and gastric neutrophil infiltration in rats given indomethacin were significantly inhibited by the oral administration of plaunotol. CONCLUSIONS: Plaunotol inhibits indomethacin-induced gastric mucosal injury, at least in part by inhibiting neutrophil activation.

Animals↗
PubMed1999

Regulation of the genes for arginase isoforms and related enzymes in mouse macrophages by lipopolysaccharide.

Arginase exists in two isoforms, the hepatic (arginase I) and extrahepatic types (arginase II). Arginase I is markedly induced in rat peritoneal macrophages and rat tissues in vivo by bacterial lipopolysaccharide (LPS). In contrast, both arginase I and arginase II are induced in LPS-activated mouse peritoneal macrophages. In the present study, expression of arginase isoforms and related enzymes was studied in mouse tissues in vivo and in peritoneal macrophages with RNA blot and immunoblot analyses and enzyme assay. When mice were injected intraperitoneally with LPS, inducible nitric oxide synthase (iNOS) and arginase II were induced early in the lung and spleen. mRNAs for argininosuccinate synthase (AS) and ornithine decarboxylase (ODC) were also induced early. In comparison, arginase I was induced later in the lung. Early induction of iNOS, arginase II, AS, ODC, and cationic amino acid transporter 2 and late induction of arginase I were observed in LPS-activated peritoneal macrophages. These results indicate that the genes for the two arginase isoforms are regulated differentially. Possible roles of the arginase isoforms in the regulation of nitric oxide production and in polyamine synthesis are discussed.

Animals↗
PubMed1999

Phase II study of area under the plasma-concentration-versus-time curve-based carboplatin plus standard-dose intravenous etoposide in elderly patients with small-cell lung cancer.

PURPOSE: The target area under the plasma-concentration-versus-time curve (AUC)-based dosing of carboplatin using Calvert's formula is expected to result in more acceptable toxicity and greater efficacy in elderly patients with small-cell lung cancer (SCLC) than the body surface area-based dosing strategy. This phase II study was designed to determine the toxicity and efficacy of carboplatin based on Calvert's formula plus the standard dose of intravenous etoposide for elderly patients with SCLC. PATIENTS AND METHODS: Carboplatin, dosed to a target AUC of 5 x (24-hour creatinine clearance + 25), was given intravenously on day 1 and etoposide 100 mg/m(2) was given intravenously on days 1, 2, and 3. Patients aged >/= 70 years old with a performance status of 0 to 2 were eligible. RESULTS: Thirty-six patients were enrolled onto the study. The patient characteristics were as follows: median age, 73 years; limited disease (LD), 16 patients; and extensive disease (ED), 20 patients. Grades 3 and 4 leukopenia occurred in 57% and 3% of patients, and grades 3 and 4 thrombocytopenia occurred in 40% and 11% of patients, respectively. There was one treatment-related death due to hemoptysis. Other toxicities were relatively mild. There were two complete responses and 25 partial responses, for a response rate of 75%. The median survival time was 10.8 months (LD, 11.6 months; ED, 10.1 months), and the 1-year survival rate was 47%. CONCLUSION: This carboplatin/etoposide combination chemotherapy is an active and relatively nontoxic regimen in elderly patients with SCLC, which suggests that the combination may be suitable for randomized controlled trials.

Aged↗
PubMed1999

[A giant invasive thymoma made resectable by cisplatin + vincristine + doxorubicin + etoposide (CODE)].

A 39-year-old man experienced cough and dyspnea by right massive pleural effusion. A large tumor was found in the anterior mediastinum and it had invaded the chest wall all around. The diagnosis was invasive thymoma stage IV a by biopsy. His tumor was too large to be resected, so chemotherapy was planned. The tumor responded well to cisplatin + etoposide until day 7, but it relapsed immediately between doses. Hence, we administered cisplatin + vincristine + doxorubicin + etoposide (CODE) with G-CSF for its high-dose intensity. The tumor diminished in size, and the chest wall invasion almost disappeared. An operation was performed. We describe our experience with a case of invasive thymoma which responded to CODE.

Adult↗
PubMed1999

[A clinical application of laser scanning cytometer--the significance in the cytology as an additional diagnostic technique].

Laser scanning cytometer (LSC) is a new machine similar to flow cytometer but with advantages for certain clinical and research applications. LSC is a microscope based and measures cells on a slide with the position of each cell on the slide. This new technique of LSC can be utilized on extremely small specimens and enables direct correlation of all of the measured fluorescent parameters with light microscopic cytologic morphology. To date, LSC has been successfully used to perform DNA content analysis of numerous specimen types and automated analysis of fluorescence in situ hybridization specimens. In this report, we describe characteristics of LSC comparison with flow cytometry and a clinical application of LSC focused on DNA content analysis in clinical specimens with pulmonary disorders. LSC provides a number of benefits that may make it more suitable for clinical laboratories than FCM.

Bronchi↗
PubMed1998

Intracellular accumulation of thallium as a marker of cisplatin cytotoxicity in nonsmall cell lung carcinoma: an application of inductively coupled plasma mass spectrometry.

BACKGROUND: Thallium-201 (201Tl) scintigraphy has been used to detect malignant pulmonary disease. The mechanism of Tl influx in tumor cells is believed to be similar to that of cisplatin (CDDP) mediated by sodium- and potassium-activated adenosine triphosphatase (Na-K ATPase), and the Na-K ATPase activity may determine the cellular CDDP accumulation and sensitivity to CDDP. The objective of this study was to determine the accumulation of CDDP and Tl in vitro by using inductively coupled plasma mass spectrometry (ICP-MS), a new analytic technique for detecting ultra trace elements, and to evaluate the correlations between cellular CDDP and Tl accumulation, between CDDP 50% inhibitory concentration (IC50) values and cellular CDDP accumulation, and between CDDP IC50 values and cellular Tl accumulation. METHODS: Eight nonsmall cell lung carcinoma (NSCLC) cell lines were used (five adenocarcinomas and three squamous cell carcinomas). The cell lines were exposed to CDDP or Tl for 1 hour, and the resulting cellular accumulation of platinum and Tl was determined by ICP-MS. CDDP IC50 values were determined by a soluble tetrazolium/formazan assay. RESULTS: The authors were able to measure cellular CDDP and Tl accumulation precisely, and heterogeneity in the cellular accumulation of CDDP and Tl existed among the NSCLC cell lines. A significant inverse correlation was observed between CDDP IC50 values and the cellular accumulation of both CDDP and Tl. CONCLUSIONS: ICP-MS is suitable for the determination of cellular CDDP and Tl accumulation in NSCLC cell lines. Cellular Tl accumulation determined by ICP-MS may reflect CDDP cytotoxicity rather than cellular CDDP accumulation.

Adenocarcinoma↗
PubMed1998

Surgery for cholecystocholedocholithiasis in a patient with asymptomatic essential thrombocythemia: report of a case.

Essential thrombocythemia (ET) is a myeloproliferative disorder characterized by a remarkable increase in the platelet count and various clinical symptoms. The perioperative management of patients with ET has yet to be determined, especially when there are no clinical symptoms. We report herein the case of a woman with gallstones whose preoperative hematological data showed remarkable thrombocythemia, but her coagulation studies were normal. The Philadelphia chromosome was negative and bone marrow cytology showed a marked increase in megakaryocytes. Surgery was performed under a diagnosis of cholelithiasis with ET. Considering her severe thrombocythemia and obesity, sufficient heparin was administered to prevent deep vein thrombosis; however, this precipitated postoperative bleeding, necessitating a reoperation. A functional abnormality of the patient's platelets was suspected, and the aggregation by adenosine diphosphate was subsequently found to be significantly inhibited. As patients having ET with no symptoms might have depressed platelet aggregability despite remarkable thrombocythemia, when abdominal surgery is performed, prophylactic therapy for deep vein thrombosis should be avoided. Hence, the preoperative aggregation study of platelets might offer useful information about whether postoperative antithrombotic therapy is indicated.

Anticoagulants↗
PubMed1998

Malignant fibrous histiocytoma of the stomach: report of two cases.

Malignant fibrous histiocytoma (MFH) in the stomach is very rare, and only four cases have been reported. As a result, there is still little understanding of its clinical and pathological features. We recently experienced two cases of gastric MFH. The first case was a 78-year-old man with epigastralgia and a loss of body weight. Endoscopy revealed an ulcerated submucosal tumor. A gastrectomy was performed and the diagnosis of MFH was made histopathologically. The second case was a 77-year-old man with pulmonary symptoms. An image diagnosis indicated a strong suspicion of lung cancer, and a right middle and lower lobectomy was thus performed. One month after the operation, a bleeding gastric tumor was found and therefore a gastrectomy was performed. Both tumors were diagnosed as MFH. From the analysis of six reported cases including ours, a preoperative correct diagnosis is found to be difficult although the lesion has grown to a considerable size at the time of operation. Since a metastatic lung lesion was first detected in two out of six cases, it is thus recommended that the stomach should be examined when lung MFH is found. Considering the high mortality and the short survival in the six cases, the prognosis for gastric MFH seems to be poorer than that in the extremities. However, lymph node metastasis is uncommon, and a curative resection is possible in some cases such as in our second case.

Adult↗
PubMed1998

Role of neutrophil elastase in stress-induced gastric mucosal injury in rats.

Activated neutrophils play an important role in tissue injury by releasing various inflammatory mediators capable of damaging endothelial cells. To investigate whether neutrophil elastase (NE) is involved in stress-induced gastric mucosal injury, we examined the effects of 2 NE inhibitors (ONO-5046 and L-658 758) as well as nitrogen mustard-induced leukocytopenia on the formation of gastric mucosal lesions, gastric mucosal blood flow, gastric mucosal microvascular permeability, and gastric neutrophil accumulation in rats subjected to water immersion-restraint stress (WIR). Gastric mucosal injury peaked 8 hours after WIR. Gastric mucosal blood flow, as measured by laser-Doppler flow cytometry, decreased to 45% of its initial level 8 hours after WIR. Gastric mucosal microvascular permeability, evaluated by Evans blue dye leakage to the gastric mucosa, showed an increase, peaking 8 hours after WIR. Gastric accumulation of neutrophils, determined by measuring gastric myeloperoxidase activity and by histologic examination, was also significantly increased 8 hours after WIR. Both of the NE inhibitors markedly prevented the formation of gastric mucosal lesions. They also decreased the reduction in gastric mucosal blood flow seen in animals subjected to WIR while preventing increases in gastric mucosal microvascular permeability. Gastric neutrophil accumulation was significantly reduced in animals given either inhibitor 8 hours after WIR. Leukocytopenia produced effects similar to those produced by the inhibitors. Taken together, these observations strongly suggest that NE promotes stress-induced gastric mucosal injury in rats by reducing gastric mucosal blood flow and increasing neutrophil accumulation.

Animals↗
PubMed1998

Predicting chemotherapeutic response to small-cell lung cancer of platinum compounds by thallium-201 single-photon emission computerized tomography.

Thallium-201 single-photon emission computerized tomography (SPECT) was used to clarify the relationship between 201Tl uptake and the response in chemotherapy to platinum compounds in 21 patients with small-cell lung cancer. 201Tl-SPECT scans were obtained twice: at 15 min (early scan) and 120 min (delayed scan) after an intravenous injection of 111 MBq (3 mCi) of thallium-201 chloride. We obtained the uptake ratio from each scan and calculated the retention index:uptake ratio = region of interest uptake/contralateral normal lung uptake; retention index = (delayed ratio - early ratio)/early ratio. After 201Tl scintigraphy, 12 patients received chemotherapy consisting of platinum compounds and nine were treated with chemoradiation. Among patients receiving only chemotherapy, the retention index correlated with the responses to chemotherapy. In an in vitro study, ouabain, an inhibitor of the Na,K-ATPase pump, reduced sensitivity to cisplatin and inhibited intracellular thallium uptake in the small-cell lung cancer cell line. These studies suggest that 201Tl-SPECT is a useful indicator of response to chemotherapy with platinum compounds in small-cell lung cancer, and that Na,K-ATPase is commonly involved in transporting both thallium and platinum compounds into cancer cells.

Aged↗
PubMed1998

Rapid diagnosis at the outpatient clinic for breast tumors by fine needle aspiration cytology. The utility.

The aim of this study was to emphasize the utility and prove the accuracy of rapid diagnosis at the outpatient clinic for breast tumors by fine needle aspiration cytology [FNAC]. Rapid diagnosis for breast tumors by FNAC is performed on the same day just after mammography and echonography are carried out at our hospital and the result reported to the patients while they are waiting at the outpatient clinic. We evaluated FNAC by rapid diagnosis at the outpatient clinic for 1,786 breast tumors during the last ten years. The cases of no judgement (Class 0) were 11%, negative cases (Class I & II) 72%, suspicious cases (Class III) 7%, and positive cases (Class IV & V) 10%. We experienced only 4 false negative cases and 0 false positive cases among 1,198 cases during the last 5 years, whereas there were 8 false negative cases and 2 false positive cases among 588 cases during the first 5 years. Two false positive cases in the the first 5 years were judged as Class IV, but definitive surgery [mastectomy] was not performed because rapid diagnosis during the operation by frozen section confirmed no malignancy. As a result, all the cases in which mastectomies were performed up to now were confirmed malignant. We emphasize that rapid diagnosis at the outpatient clinic for breast tumors by FNAC is very useful for early detection and treatment and it is very important to consider the histological type of breast tumors by FNAC to prevent misjudgement.

Adult↗
PubMed1998

Bronchogenic cyst with high carbohydrate antigen 19-9 in the cyst fluid and the serum.

A mass of 8 cm in diameter was revealed in the right upper lung field of a 46-year-old female patient. The chest X-ray film taken one year previously revealed only a linear shadow in the same position, which was thought to be a vacant cyst. The levels of carbohydrate antigen (CA) 19-9 in cyst fluid and serum were elevated, at 410,000 and 130 U/ml, respectively. After surgical resection, serum CA19-9 returned to normal. Pathologically, the cyst wall was lined with bronchial epithelium with no evidence of malignancy. Immunohistochemical study revealed CA19-9 positivity in the bronchial epithelium of the cyst wall.

Body Fluids↗