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Biomedical subjects

H Iwase

Publications and source records attributed to H Iwase.

At least 55 records · Page 3Linked to original sources
PubMed2001

Endoscopic ablation with cyanoacrylate glue for isolated gastric variceal bleeding.

BACKGROUND: Endoscopic ablation with cyanoacrylate glue may achieve gastric variceal obliteration. A prospective evaluation of its therapeutic effects on bleeding gastric varices was conducted, focusing on endoscopic features. METHODS: Thirty-seven patients with bleeding gastric varices underwent endoscopic ablation with cyanoacrylate. RESULTS: Patients with localized-type gastric varices (n = 14) had a better clinical course in terms of recurrent bleeding, variceal eradication, and survival than those with diffuse-type gastric varices (n = 23) after endoscopic ablation with cyanoacrylate. These clinical effects were related to the vascular anatomy of the gastric varices as determined by varicography and 3-dimensional CT. Type 1 vascular anatomy (one varicose vessel without noticeable ramifications) was much more common (86%) in localized-type gastric varices, whereas type 2 vascular anatomy (multiple varicose vessels with complex connecting ramifications) was found almost exclusively (91%) in diffuse-type gastric varices. CONCLUSIONS: Endoscopic ablation with cyanoacrylate is an effective and safe procedure for patients with bleeding gastric varices. Determination of variceal anatomy may be useful for improving treatment strategies for such patients.

Adhesives↗
PubMed2001

Thiol-oxidizing agent diamide and acidic pH enhance lipid peroxidation of rat heart mitochondria and cardiolipin-cytochrome c complex.

In this study, we investigated lipid peroxidation in rat heart mitochondria hydrolyzed by phospholipase A2 (PLA2) and lipid peroxidation in a mitochondrial-mimetic lipid peroxidation system, where phospholipids such as cardiolipin (CL) and cytochrome c (Cyt c) were first mixed together and then PLA2 and calcium chloride were added to the mixture (CL-Cyt c-PLA2 system). Production of hydroperoxy and hydroxy compounds of linoleic acid (LA) in the mixture was measured by high performance liquid chromatography. The ratio of the total amount of hydroperoxy and hydroxy compounds of LA to that of LA was calculated as an index for lipid peroxidation (1000 x mol/mol). The index for lipid peroxidation in the rat heart mitochondria hydrolyzed by PLA2 at the physiological pH of 7.4 was 22.8 +/- 2.2 (mean +/- SD, n = 4) and that at the acidic pH of 6.7 was 41.8 +/- 2.0. In the presence of the thiol (SH)-oxidizing agent diamide, the index was 47.0 +/- 2.6 (pH 7.4). In the CL-Cyt c-PLA2 system, lipid peroxidation seemed to be due to three mechanisms: (1) oxidation of the LA (nonreleased form) constituent of CL by Cyt c (oxidation of CL by Cyt c); (2) oxidation of free LA, released from CL, involving the oxidation of CL by Cyt c (free LA oxidation by the CL-Cyt c complex); and (3) oxidation of free LA, released from CL, by Cyt c and calcium ions (LA-Cyt c-Ca system). The lipid peroxidation of the CL-Cyt c-PLA2 system was also enhanced by the addition of diamide and by an acidic pH of 6.7. The fact that the SH-oxidizing agent enhanced the lipid peroxidation in the CL-Cyt c-PLA2 system suggested that SH groups in the hemoprotein played an inhibitory role in lipid peroxidation in the system.

Animals↗
PubMed2001

Clinically unidentified dissection of vertebral artery as a cause of cerebellar infarction.

BACKGROUND AND PURPOSE: Dissection of vertebral arteries has been reported in association with minor neck movements without signs of trauma on the surface of the neck. In addition, injury of a vertebral artery can cause brain infarctions. However, few cases have been reported in which fatal brain infarction was due to nonocclusive, clinically undetected, traumatic thrombus formation in a vertebral artery. CASE DESCRIPTION: A 62-year-old man was hit by a car, and a right cerebellar infarction was found the day after the accident. The cause of the infarction could not be detected by angiography. Although the patient recovered favorably after surgical removal of the right lateral hemisphere of the cerebellum, he died suddenly 2 weeks after the accident. An autopsy and a microscopic study revealed pulmonary thromboembolism and organizing traumatic lesions of the right vertebral artery without occlusion or noteworthy stenosis of the artery. CONCLUSIONS: We concluded that the patient sustained traumatic lesions of the right vertebral artery during the traffic accident 2 weeks before death and that his cerebellar infarction was due to a thrombus resulting from these traumatic lesions.

Accidents, Traffic↗
PubMed2001

[A phase I study of docetaxel (TXT) and doxifluridine (5'-DFUR) combination therapy in patients with advanced and recurrent breast cancer].

We investigated efficacy and tolerance of chemotherapy with doxifluridine (5'-DFUR) and docetaxel (TXT) in advanced/recurrent breast cancer. Subjects were enrolled by central registration. The regimen included 5'-DFUR orally for 14 consecutive days, and TXT intravenously on day 8. It was repeated every 3 weeks, as long as possible, including dosage levels of 5 scheduled steps. Patient registration was started in August 1999 and 5 patients given level 1 regimen (5'-DFUR, 800 mg/day; TXT, 50 mg/m2) were evaluated. Although the results revealed neutropenia of grade 3 in 4/5 patients and leukocytopenia in 2/5 patients, no other side effects were observed. Taking into consideration the toxicity profiles of each drug in level 1, a level 2b regimen (5'-DFUR, 800 mg/day; TXT, 60 mg/m2) was accepted. Seven patients were registered for level 2b dosage and were examined for the safety of the regimen. Two patients discontinued the level 2b regimen due to percutaneous adverse reactions (DLT) and 6/7 patients developed neutropenia of grade 4. Clinical effects in level 1 group included: 1 CR, 2 PR, 1 long NC (NC longer than 24 weeks), and 1 NE, for a response rate of 60.0% (3/5 patients). Those in level 2b included: 2 CR, 2 PR, 1 NC, and 2 NE, for a response rate of 57.1% (4/7 patients). Based on the safety and efficacy of the combined therapy, the recommended dosage of this regimen is 5'-DFUR, 800 mg/day, combined with TXT, 60 mg/m2. A Phase II study is being conducted using this dosage.

Adult↗
PubMed2001

[Complete response in a case of advanced gastric cancer with liver and intra-abdominal lymph node metastases treated by combined chemotherapy of TS-1 and CDDP].

A 67-year-old male patient with gastric cancer of Borrmann type 2 and liver and intra-abdominal lymph node metastases was treated by combined chemotherapy of TS-1 and CDDP TS-1 (100 mg/day) was administered for 14 days followed by 14 days rest as one course. CDDP (70 mg/m2) was administered in 24-hour continuous intravenous infusion at 8 days after the start of TS-1. After 3 courses of treatment, X-ray and endoscopic examinations revealed complete disappearance of the primary tumor and no cancer cells were detected by endoscopic biopsy. A CT-scan also showed complete disappearance of metastatic sites. This combined chemotherapy was finished after 5 courses, and no high grade toxicities (WHO grade 3 or 4), specifically nausea, diarrhea, or leucocytopenia, were seen. This TS-1/CDDP chemotherapy seemed to be effective for advanced gastric cancer in view of toxicities, antitumor effect and QOL of the patient.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Loss of heterozygosity and microsatellite instability in ductal carcinoma in situ of the breast.

To investigate the alterations of genetic instabilities in carcinogenesis of the breast, we analyzed the allelotypic profile of 65 ductal carcinomas in situ (DCIS), compared with that of 207 invasive ductal carcinomas (IDC) of the breast. These studies were performed by means of examining microsatellite-length polymorphisms at seven loci (AluVpa, ESR, D11S988, D13S267, D16S398, D17S1159, and D17S855) from microdissected paraffin sections. Allelic loss or imbalance, considered a loss of heterozygosity (LOH), tended to be more frequently seen in IDC than in DCIS. In particular, the frequency of LOH at the 17p locus was significantly higher in IDC than in DCIS (42 vs. 23%, P=0.022). LOH in DCIS was most frequently seen at D16S398 (26%). LOH frequency at D16S398 in low- and intermediate-grade DCIS was higher than that in high-grade DCIS, while LOH frequencies at D11S988 and D17S1159 in low- and intermediate-grade DCIS was lower than those in high-grade DCIS. LOH frequency at D11S988 in non-comedo type DCIS was lower than that in comedo type DCIS. Furthermore, the frequency of microsatellite instability (MSI) at only one locus in DCIS (28%) was statistically higher than that in IDC (6%) (P<0.001), while there was no difference between the frequency of MSI at multiple loci in DCIS (6%) and that in IDC (3%). Together, these observations indicate that chromosomal losses of 16q may occur in low- and intermediate-grade DCIS and those of 11p and 17p may occur high-grade DCIS, and that MSI occurring at only one locus is not yet clear and MSI at multiple loci is uncommon in not only IDC but also DCIS of the breast.

Adult↗
PubMed2000

cis-9,10-Methylenehexadecanoic acid inhibits contractility and actomyosin ATPase activity of guinea pig myocardium.

Superfusion with a cyclopropane fatty acid, cis-9, 10-methylenehexadecanoic acid (10-300 microM), reduced the contractility of papillary muscle isolated from guinea pigs in a dose-dependent manner. cis-9,10-Methylenehexadecanoic acid also inhibited the Mg(2+)-ATPase activity of guinea pig papillary myocardium by about 40% at 400 microM. Since cis-9, 10-methylenehexadecanoic acid 4 microM inhibited the K(+)-EDTA-ATPase activity inherent in myosin's catalytic activity by about 25%, the fatty acid was thought to interact with the catalytic center of the myosin molecule.

Animals↗
PubMed2000

Assay of ATPase and Na,K-ATPase activity using high-performance liquid chromatographic determination of ADP derived from ATP.

An HPLC assay for determination of ATPase activity was developed and validated. After stopping the enzyme reaction of the enzyme source (rat renal cortical basolateral membranes) with ATP, products derived from ATP were analyzed by two methods; HPLC determination of ADP derived from ATP, and colorimetry of inorganic phosphorus (Pi) released from ATP. This HPLC procedure was precise and linear over the range of protein amount of the enzyme source studied, and the intra-and inter-assay variations were lower than 10%. The values that were obtained by the two methods revealed a significant correlation. Also, even when the samples contained Pi or were contaminated with Pi, this HPLC method allowed determination of ATPase activity. In addition, when ouabain was used as an inhibitor, the HPLC method was found to be applicable for Na,K-ATPase determination. This indicated that this HPLC assay would enable determination of ATPases other than Na,K-ATPase, when other inhibitors are employed instead of ouabain.

Adenosine Diphosphate↗
PubMed2000

Use of nucleic acids in the mobile phase for the determination of ascorbic acid in foods by high-performance liquid chromatography with electrochemical detection.

The sodium salts of amino acids, nucleic acids and organic acids were examined in a new mobile phase for the determination of ascorbic acid (AA) in foods. It was possible to use disodium guanosine-5'-monophosphate (GMP) (20 mM GMP, pH 2.1) in a new mobile phase after comparison of five mobile phases. The proposed method is simple, rapid (analysis time: ca. 6 min), sensitive (detection limit: ca. 0.1 ng per injection (5 microl) at a signal-to-noise ratio of 3), highly selective and reproducible [relative standard deviation: ca. 2.7% (n=7)]. The calibration graph of AA was linear in the range of 0.1 to 50 ng per injection (5 microl). Recovery of AA was over 90% by the standard addition method.

Ascorbic Acid↗
PubMed2000

Determination of tocopherol acetate in emulsified nutritional supplements by solid-phase extraction and high-performance liquid chromatography with fluorescence detection.

The present paper deals with a method of solid-phase extraction of tocopherol acetate (TA, 49.6 microg/g) from emulsified nutritional supplements, which contains 50 kinds of compounds, followed by high-performance liquid chromatography (HPLC) with fluorescence detection The TA concentration is 5 to approximately 100,000 times lower than that of other compounds in the samples. Measuring the loading capacity of the larger amounts of vegetable oil onto the Bond Elut C18 cartridge was examined for the complete retention of smaller level of TA. A sample solution was applied to a solid-phase extraction cartridge and then TA was eluted by acetonitrile followed by HPLC. This method was suitable for the determination of TA in emulsified nutritional supplements. The proposed method was simple, rapid (analysis time: ca. 15 min), sensitive [detection limit: ca. 0.1 ng per injection (100 microl) at a signal-to-noise ratio of 3:1], and reproducible (relative standard deviation: ca. 2.5% (n=5)). The calibration graph of TA was linear in the range of 0.1 to 100 ng per injection (100 microl). Recovery of TA was over 90% by the standard addition method.

Calibration↗
PubMed2000

Determination of vitamin D2 in emulsified nutritional supplements by solid-phase extraction and column-switching high-performance liquid chromatography with UV detection.

This paper deals with a method for solid-phase extraction of trace amounts of vitamin D2 (VD2, 19 ng/g) from emulsified nutritional supplements, which contain 50 kinds of compounds, followed by column-switching high-performance liquid chromatography (HPLC) with UV detection at 265 nm. VD2 is present at 1000-20,000,000 times lower concentration than other components. Bond Elut C18 cartridge was chosen as for the emulsified nutritional supplements after comparison with eight other types. A sample solution was applied to the solid-phase extraction cartridge and VD2 was eluted by methanol followed by HPLC. The effects of sample pH, eluent composition and eluate volume on the retention and elution of VD2 on Bond Elut C18 cartridge were examined. The resulting method was simple, rapid (analysis time: approximately 20 min), sensitive (detection limit: approximately 0.1 ng per injection (200 microl) at a signal-to-noise ratio 3:1), and reproducible (relative standard deviation: approximately 6.2%, n=5). The calibration graph for VD2 was linear in the range of 0.1-3 ng per injection (200 microl). Recovery of VD2 was approximately 80% by the standard addition method.

Calibration↗
PubMed2000

Use of an amino acid in the mobile phase for the determination of ascorbic acid in food by high-performance liquid chromatography with electrochemical detection.

The possibility of using monosodium L-glutamate (MSG) (20 mM MSG, pH 2.1) in the mobile phase for the determination of ascorbic acid (AA) in foods by high-performance liquid chromatography (HPLC) with electrochemical detection was examined. The hydrodynamic voltammogram of AA and the background current were also examined. The applied potential was set at 400 mV versus an Ag/AgCl reference electrode. It was demonstrated that MSG was a useful mobile phase for the determination of AA in foods. This paper also examines the stability of AA under various conditions in order to optimize HPLC conditions and the pre-run sample stabilization. The proposed method is simple, rapid (analysis time: approximately 6 min), sensitive (detection limit: approximately 0.1 ng per injection (5 microl) at a signal-to-noise ratio of 3), highly selective and reproducible (relative standard deviation: approximately 2.5%, n=7). The calibration graph of AA was linear in the range 0.1-50 ng per injection (5 microl). Recovery of AA was over 90% by the standard addition method.

Amino Acids↗
PubMed2000

Determination of vitamin K1 in emulsified nutritional supplements by solid-phase extraction and high-performance liquid chromatography with postcolumn reduction on a platinum catalyst and fluorescence detection.

Determination of small amounts of vitamin K1 (0.8 microg/g) in nutritional supplements with high fat content (20 mg/g) was performed by solid-phase extraction and high-performance liquid chromatography (HPLC) with fluorescence detection after reduction on a platinum oxide catalyst. The concentration ratio of plant oils to vitamin K1 (0.8 microg/g) was about 25,000:1. A sample solution was applied to a solid-phase extraction cartridge and vitamin K1 was eluted with ethanol, followed by HPLC. The proposed method was simple, rapid (analysis time: ca. 12 min), sensitive [detection limit: ca. 0.1 pg per injection (100 microl) at a signal-to-noise ratio of 3:1], highly selective and reproducible [relative standard deviation: ca. 1.3%. (n=5)]. The calibration graph of vitamin K1 was linear in the range of 0-2 pg per injection (100 microl). Recovery of vitamin K1 was over 90% by the standard addition method.

Catalysis↗
PubMed2000

Pharmacokinetics and biodisposition of fluorescein-labeled arabinogalactan in rats.

Fluorescein-labeled arabinogalactan (FA) was prepared by the reaction with FITC in methyl sulphoxide according to the method of deBelder and Granath. A systemic kinetic analysis of FA in rats was carried out by using a specific high-performance size-exclusion chromatography. Intravenously administered FA was rapidly eliminated from the blood circulation followed by an appreciable distribution to the liver and kidney. FA was accumulated in these organs over a long period whereas negligible levels of FA were detected in the other organs. A marked dose-dependency was seen in the hepatic uptake of FA which was markedly reduced by coinjected asialofetuin whereas the renal uptake of FA was not altered. Measurement of the hepatocellular localization demonstrated the overwhelming distribution of FA in the parenchymal liver cell fraction. Furthermore, the microscopic examination revealed FA that was effectively endocytosed by the parenchymal liver cells. These results suggested that FA which is bound to the asialoglycoprotein receptor with a high affinity is subsequently internalized to the hepatocyte via receptor-mediated endocytosis. FA was partially activated by periodate oxidation in order to acquire aldehyde groups to which guest molecules can be bound. A 12.5% oxidized arabinogalactan keeping a hepatocellular targetability showed a good conjugating reactivity to guest molecules via Schiff-base formation or by reductive amination. It was suggested that arabinogalactan can serve as a potential carrier for the delivery of enzymes and drugs to the parenchymal liver cells via the asialoglycoprotein receptor.

Animals↗
PubMed2000

Direct evidence for decreased sialylation and galactosylation of human serum IgA1 Fc O-glycosylated hinge peptides in IgA nephropathy by mass spectrometry.

Human serum immunoglobulin IgA1 is produced in bone marrow and interacts with specific cellular receptors that mediate biological events. In this study, we have analyzed the detailed glycoform structure of the human serum IgA1 Fc O-glycosylated hinge region by electrospray ionization liquid mass spectrometry. The IgA1 fragments containing the hinge glycopeptide were separated from 4 IgA nephropathy patient (IgAN) pooled sera, 10 non-IgAN pooled sera with other primary glomerulonephritides, and 5 healthy control subject pooled sera by trypsin treatment and Jacalin affinity chromatography. The molecular weights of IgA1 hinge glycopeptide were estimated using mass spectrometry, and 13 sialo and 8 asialo glycopeptide groups were identified. The results obtained clearly showed a decrease of GalNAc, Gal, and sialic acid in IgAN compared with non-IgAN and normal controls, and those strongly suggested the possibility that the decreased galactosylation and sialylation of the IgA1 hinge result in its glomerular deposition in IgAN.

Adult↗
PubMed2000

Effect of cytochrome c on the linoleic acid-degrading activity of porcine leukocyte 12-lipoxygenase.

Hemoproteins are known to have quasilipoxygenase activity that converts linoleic acid (LA) to its hydroperoxides. However, it is not still clear whether, like lipoxygenases, hemoproteins can produce LA hydroperoxides when the LA is part of a mixture containing many different saturated and unsaturated fatty acids. In this study, we found that such hemoprotein as cytochrome c (Cyt c) did not produce LA hydroperoxides from the phospholipase A(2) (PL-A(2)) hydrolysis products of egg yolk phosphatidylcholine (PC). We also found that traces of hydroperoxides and a high concentration of the target unsaturated fatty acid (LA) needs to be present in a fatty acid mixture before the quasi-lipoxygenase activity of Cyt c becomes apparent. We also attempted to elucidate how Cyt c interact with porcine leukocyte 12-lipoxygenase (12-LOX). Hemoproteins are known to possess pseudo-lipohydroperoxidase activity, and can remove the hydroperoxides of unsaturated fatty acids from a reaction mixture. However, we found that Cyt c catalyzed the reaction by which hydroperoxides degrade LA, and thus enhanced the LA-degrading activity of 12-LOX. This hemoprotein-induced promotion of the ability of 12-LOX to degrade LA was observed even when the reaction mixture contained many different saturated and unsaturated fatty acids.

Animals↗
PubMed2000

Postmortem changes in cytochrome c oxidase activity in various organs of the rat and in human heart.

Cytochrome c oxidase (COX), a mitochondrial enzyme, is inactivated by cyanide or carbon monoxide (CO) intoxication. To test whether cytochrome c has potential as an indicator of these toxins in cadavers, we measured COX activity in the main organs of the rat, and in the human heart, at various times after death. Each tissue sample or organ was homogenized and the COX activity in the mitochondrial fraction was measured using ferrous cytochrome c as the substrate. COX activity was significantly higher in rat brain, heart and kidney than in lung and liver from 0 to 4 days after death. The loss of COX activity was significantly slower in the brain and heart than in the lung, liver and kidney. Most importantly, COX activity correlated with the time-since-death for each of the rat organs we tested (r2=0.70-0.95), but for the human heart (r2=0.47). It may be possible that COX activity is likely to be a useful indicator of the time-since-death, and is worth pursuing as an indicator of the tissue cyanide and CO content.

Adolescent↗