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Biomedical subjects

Y Yamane

Publications and source records attributed to Y Yamane.

At least 145 records · Page 8Linked to original sources
PubMed1995

Effects of chronic right ventricular pressure overload on myocardial glucose and free fatty acid metabolism in the conscious rat.

OBJECTIVE: The aim was to investigate the effects of chronic right ventricular pressure overload on myocardial glucose and free fatty acid metabolism in the right ventricular free wall, ventricular septum, and left ventricular free wall. METHODS: Using a glucose analogue, 14C-2-deoxyglucose (14C-DG), and a fatty acid analogue, 14C-beta methylheptadecanoic acid (14C-BMHDA), quantitative autoradiography was performed in conscious rats with 4 week pulmonary artery constriction. RESULTS: In rats with chronic pulmonary artery constriction, right ventricular peak systolic pressure and right ventricular weight to body weight ratio increased by 88% and 127%, respectively, compared with sham operated rats (P < 0.01 for each). In the right ventricular free wall, 14C-DG deposition increased but 14C-BMHDA accumulation did not differ in the chronic pulmonary artery constricted rats compared with sham operated rats [212(SEM 27), n = 6 v 101(15) nCi.g-1, n = 4, P < 0.01, and 406(40), n = 6, v 333(48) nCi.g-1, n = 4, NS, respectively]. In sham operated rats, 14C-DG and 14C-BMHDA deposition did not differ between the ventricular septum and the left ventricular free wall. In contrast, 14C-DG and 14C-BMHDA accumulations were lower in the ventricular septum compared with the left ventricular free wall wall in chronic pulmonary artery constricted rats. Myocardial blood flow assessed by 14C-iodoantipyrine was homogeneously distributed throughout both ventricles. CONCLUSIONS: Chronic right ventricular pressure overload increases myocardial glucose uptake and/or its phosphorylation in the right ventricular free wall, and alters the regional profiles of substrate use in the ventricular septum and left ventricular free wall despite the homogeneous blood flow distribution. The results of the acute right ventricular pressure overload study, in which only right ventricular 14C-BMHDA deposition was increased compared with controls, suggest that the findings obtained from chronic pulmonary artery constricted rats cannot be explained by increased right ventricular pressure alone.

Animals↗
PubMed1995

Quantitative double-tracer autoradiography with tritium and carbon-14 using imaging plates: application to myocardial metabolic studies in rats.

UNLABELLED: A system for 3H- and 14C-labeled macroautoradiography was developed that is able to quantify the tissue radioactivity of two tracers using imaging plates. METHODS: Discrimination between electrons emitted from 3H and 14C is possible on the basis of their different energy distributions. The general use imaging plate with a protective layer detects 14C radioactivity, but it does not detect 3H radioactivity which has a lower energy distribution than 14C. Recently, a 3H-sensitive imaging plate without a protective layer was developed. The 3H distribution image is obtained by subtracting the UR image from the TR image. For quantification of the tissue radioactivity of 3H and 14C, we obtained tissue equivalent values (Bq/mg) of commercially available 3H- and 14C-labeled graded standards using different dilutions of labeled heart paste and liquid scintillation counting. Using the 3H- and 14C-labeled graded standards, we confirmed the validity of the quantification of the 3H-autoradiographic intensity using this subtraction method. We applied this method to a rat model of acute myocardial ischemia to compare regional myocardial free fatty acid uptake determined by beta-methyl[1-14C]heptadecanoic acid to glucose uptake determined by 2-deoxy-D-[1-3H]glucose. RESULTS: Free fatty acid uptake was decreased sharply at the ischemic periphery where glucose uptake was preserved. CONCLUSION: This double-tracer autoradiography with 3H and 14C which has high sensitivity, a high spatial resolution of 50 microns and superior linearity with a wide dynamic range of 10(4) to 10(5) allows accurate quantification of the tissue radioactivity of the two radiopharmaceuticals.

Animals↗
PubMed1994

Phosphorus-31 nuclear magnetic resonance in vivo spectroscopy of human liver during hepatitis A virus infection.

To evaluate the changes in hepatocellular phospholipid metabolism during hepatitis virus infection, 26 patients with acute viral hepatitis A were studied by means of phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. The spectroscopy of liver showed six signal components in all patients as well as in the normal volunteers. During the early phase of illness, the phosphomonoester (PME)-phosphodiester (PDE) ratios in the patients became markedly greater than the ratios in the controls (P < 0.001). Within six weeks after the onset, the PME/PDE ratios returned to the level of controls. The time course analysis indicated an inverse correlation between the PME/PDE ratio and the period of time after onset (r = 0.738, P < 0.001). The spectral changes of human liver observed in acute viral hepatitis A are similar to those in the regenerating rat liver, indicating that 31P-NMR spectroscopy allows a noninvasive study of cell turnover in human liver disease associated with acute virus infection.

Acute Disease↗
PubMed1994

Effectiveness of fragmented autologous adipose tissue as a sealer of porous textile grafts: effect on endothelial development.

PURPOSE: This study is designed to develop a sealing method for fabric vascular prosthesis with chopped tissue fragments. METHODS: A highly porous fabric vascular prosthesis was invaginated, and a suspension of chopped autologous adipose connective tissue fragments was injected repeatedly until the pores were enmeshed with the fragments. Small tissue fragments oozed out from and firmly anchored within the interstices of the fabric, which made the outer surface smooth. The graft was then invaginated to bring the smooth surface into the luminal side. RESULTS: No blood leakage was observed in an extracorporeal in vivo shunt load test with heparin (total 1400 IU/kg, actinomycin > 1500), whereas a continuous bleeding was seen in a preclotted control graft (400 IU/kg, actinomycin 657 +/- 341). The sealed in a preclotted control graft (400 IU/kg, actinomycin 657 +/- 341). The sealed grafts were implanted in the descending thoracic aorta of 40 dogs, and an equal number of control grafts was used. The grafts were removed at selected time intervals up to 738 days. No bleeding was observed with the sealed grafts, and a thin layer of neointima was observed at 30 postoperative days. Eight (20%) of the control dogs bled to death within 24 hours of implantation. The neointima in the control animals extended from the anastomotic sites slowly with complete healing observed at 217 postoperative days. CONCLUSIONS: The autologous adipose tissue fragments could reliably seal the highly porous fabric prosthesis while allowing rapid and complete neointima healing in dogs.

Adipose Tissue↗
PubMed1994

Mechanism of cytotoxicity of paraquat. III. The effects of acute paraquat exposure on the electron transport system in rat mitochondria.

The effects of acute paraquat exposure on mitochondrial function in rat lung were studied. The paraquat dose-response study and time-effective study were performed to prove our hypothesis, enzyme toxicity especially in electron transport system following lipid peroxidation of mitochondrial inner membrane. In dose-response study, lipid peroxidation was increased by high dose paraquat exposure (40 mg/kg body weight) in rat lung, but not by low dose exposure (10 mg/kg body weight). But paraquat inhibited NADH:ubiquinone oxidoreductase (complex I) activities, especially NADH:ubiquinone reaction (NQR), even in low dose exposure. The lipid peroxide concentration did not correspond to the damage of complex I activity. In paraquat time-effective study, both lung and blood lipid peroxides increased after 6 h of paraquat exposure, decreased after 12 and 24 h and increased again after 48 h. After first peak of lipid peroxidation, NQR velocity decreased earlier than NADH:ferricyanide reaction (NFR) velocity. From these results, the cytotoxicity via mitochondrial dysfunction by acute paraquat exposure might be caused by complex I toxicity following lipid peroxidation of mitochondrial inner membrane.

Animals↗
PubMed1994

Enhancing effect of zinc acetate on the binding of 1-nitropyrene to polydeoxyguanylic-polydeoxycytidylic acid in the hypoxanthine-xanthine oxidase system.

The main aim of this research was to investigate whether conformational alteration of polydeoxyguanylic-polydeoxycytidylic acid (poly[dG-dC].poly[dG-dC]) by zinc acetate would have an effect on the binding of 1-nitropyrene(1-NP) to poly[dG-dC].poly[dG-dC]. The binding of 1-NP to poly[dG-dC].poly[dG-dC] in the hypoxanthine-xanthine oxidase system in vitro was increased by zinc acetate. This increase was abolished when EDTA was added to the preincubated mixture of poly[dG-dC].poly[dG-dC] and zinc ions. Neither the production of 1-aminopyrene and its expected intermediates, N-hydroxy-1-aminopyrene and 1-nitrosopyrene, nor the 1-NP remaining in the reaction mixture was altered by the addition of zinc acetate without poly[dG-dC].poly[dG-dC]. From these findings, it seems that the hypoxanthine-xanthine oxidase system is not activated by zinc acetate. On the other hand, under the same reaction conditions but the hypoxanthine-xanthine oxidase system and 1-NP, it has been reported that zinc ions or complexes transform the B-form of poly[dG-dC].poly[dG-dC] to the Z-form. Therefore, these findings indicate that the formation of the Z-form or intermediates from the B-form by zinc ions may promote the binding of 1-NP to poly[dG-dC].poly[dG-dC].

Acetates↗
PubMed1994

Synthesis and evaluation of novel thiazolidine derivatives as thromboxane A2 receptor antagonists.

A series of 3-benzoyl or 3-phenylsulfonyl-2-substituted thiazolidine derivatives were synthesized, and evaluated for their thromboxane A2 (TXA2) receptor-antagonizing effect on (15S)-15-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5(Z),13(E)-dienoic acid (U-46619)-induced aggregation of rabbit platelet-rich plasma (PRP). A simple 2-aryl-thiazolidine derivative, 3-benzoyl-2-(4-hydroxy-3-methoxyphenyl)thiazolidine (5a), showed mild TXA2 receptor antagonist activity. Modification of 5a led to 2-chloro-4-[3-(4-chlorophenylsulfonyl)thiazolidin-2-ylmet hyl]phenoxyacetic acid (29d), which showed 10 times more potent TXA2 receptor antagonist activity than 5a.

Animals↗
PubMed1994

[Changes in ischemic findings in ECG, obesity and serum lipids in the residents of an agricultural area in Shimane Prefecture].

Changes in ischemic findings in ECG, obesity and serum lipids and the relations among them were investigated in Sada Town, a typical agricultural and mountaineous area in Shimane Prefecture, where the mortality rate from ischemic heart disease had increased. Compared with 1983, the percentage of ischemic findings in ECG in 1990 increased, and a marked elevation of total serum cholesterol level, and relative and absolute lowering of HDL cholesterol level were observed in 1990. By observing the relations of total serum cholesterol, HDL cholesterol and the atherosclerotic index to the ischemic findings in electrocardiograms (ECG), it was found that males showed a significantly lower HDL cholesterol level and higher atherosclerotic index than the control group. In males, a relation between obesity and ischemic findings in ECG was observed. In females, a relation between obesity and the atherosclerotic index was observed; however, no relations were observed between ischemic findings and obesity. These results support the hypothesis that a marked elevation of the total serum cholesterol level, relative and absolute lowering of the HDL cholesterol level and obesity have an effect on the recent increase of male deaths due to ischemic heart disease in Sada Town, Shimane Prefecture.

Aged↗
PubMed1994

[Outpatient drainage treatment for simple spontaneous pneumothorax].

Spontaneous pneumothorax has been managed on an outpatient basis by intercostal tube drainage and a portable flutter valve device (pneumothorax set). In a series of 111 selected patients, from 14 to 75 years of age, who had no complaints such as dyspnea, had neither tension-nor hemo-pneumothorax, and could promptly return to hospital in an emergency, intercostal tube insertion and continuous negative pressure drainage were instituted at the outpatient department. After approximately one hour of suction, if an air leak ceased and the lung was re-expanded, the patient was allowed to return home with a pneumothorax set connected to the chest tube. But, if an air leak persisted, they were admitted to hospital. The outpatients were followed every 2 or 3 days thereafter, and if their course was uneventful, the chest tube was removed a week later. If the onset of lung recollapse was seen at outpatient check up, hospitalization was required. Outpatient treatment was successful in 81 cases (72.9%) of the series. However, 14 patients were hospitalized because of persistent air leak at the outpatient room, and 5 were admitted because of wound pain, re-expansion edema or other reasons. During the ambulatory course, 11 were admitted to hospital with recollapse of the lung. Bacterial cultures of drain tips were positive in 22.6% of 75 examined cases, which was a higher percentage than that associated with inpatient drainage. Wound infection with St. aureus occurred in one case after removal of the drain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

N-ras mutation and karyotypic evolution are closely associated with leukemic transformation in myelodysplastic syndrome.

We performed a longitudinal analysis of the karyotypes and N-ras gene configuration of bone marrow cells in 35 patients with myelodysplastic syndrome (MDS). Karyotypic evolution was found in eight patients, and was associated with disease progression, including leukemic transformation, in all the patients. We identified N-ras mutations in six patients, using a polymerase chain reaction (PCR) technique, in which oligonucleotide primers were constructed with induced mismatches, followed by endonuclease digestion. Direct sequencing confirmed single base substitutions at codon 12 in two patients and at codon 13 in four. The incidence of N-ras gene mutations was significantly higher in the karyotypically evolved group (five of eight patients) than in the stable group (one of 27 patients). All of five patients harboring both karyotypic evolution and an N-ras mutation showed concomitant disease progression to overt leukemia or refractory anemia with excess of blasts in transformation (RAEB-T). Two of four patients with either karyotypic evolution or N-ras mutation and six of 26 patients without any of these alterations also progressed to overt leukemia. Our results indicate that the accumulation of these genetic alterations is closely associated with leukemic transformation of MDS, although other genetic alterations may also play a key role in the remaining patients.

Adult↗
PubMed1993

The metabolism of arachidonic acid to prostaglandin E2 in plerocercoids of Spirometra erinacei.

With a simplified method of extracting and purifying prostaglandins, trace prostaglandins (nanogram order) were detected by gas chromatography-mass spectrometry. Arachidonic acid was metabolized to prostaglandin E2 (PGE2) by plerocercoids of Spirometra erinacei, the PGE2 was detected in the medium after incubation with arachidonic acid, and the role of albumin in the absorption of free arachidonic acid by plerocercoids and in the release of its metabolite was investigated. Plerocercoids absorbed arachidonic acid-binding albumin and released PGE2 efficiently. PGE2 is known to suppress the functions of mononuclear cells of the host. The selective release of PGE2 may be related to the escape mechanism of plerocercoids of S. erinacei from the host immune system to become established larva migrans, i.e., sparganosis.

Absorption↗
PubMed1993

Overproduction of riboflavin by an Arthrobacter sp. mutant resistant to 5-fluorouracil.

Antagonistic action between 5-fluorouracil (5-FU) and riboflavin (RF) was investigated. The growth of Arthrobacter sp. was inhibited by 5-FU at 5 x 10(-5) M, and the inhibition was reversed by RF at 5 x 10(-5) M. 5-FU-resistant mutants of Arthrobacter sp. were isolated and excreted RF in relatively high yields, but the wild-type strain excreted no RF. One of the mutants, strain No. 28-35, produced 223.2 micrograms ml-1 of RF in culture medium at 4 days.

Arthrobacter↗
PubMed1993

Mechanism of cytotoxicity of paraquat. I. NADH oxidation and paraquat radical formation via complex I.

The mechanism of cytotoxicity by paraquat was studied focusing attention on its effect on the mitochondrial electron transport system. Paraquat inhibited both mitochondrial and cytoplasmic malate dehydrogenase activities. NADH oxidation was verified in NADH: ubiquinone oxidoreductase (complex I) reaction mixture in which paraquat was an only electron acceptor, and paraquat radical formation was observed as turning blue of the reaction mixture. A kinetic characteristic of this enzyme reaction was that Km was so high as 4.1 mM. The maximum reaction velocity was defined in the range over pH 9. NADH autoxidation with complex I, but without paraquat, was not observed in any pH range. The maximum reaction velocity of the NADH autoxidation by paraquat without complex I was observed in pH 8.5, but the figure was so small as to be negligible. With these results, we propose the hypothesis that paraquat does not promote the autoxidation with complex I, but accepts electrons via complex I to induce paraquat radical formation.

Animals↗
PubMed1993

Studies on zoospore attracting activity. II. Synthesis of isoflavones and their attracting activity to Aphanomyces euteiches zoospore.

Nineteen isoflavones were synthesized and their attracting activity to Aphanomyces euteiches zoospore were investigated. Isoflavones (1, 2, 4, 16 and 19) with an unsubstituted B ring were synthesized by the oxidation of corresponding 2'-hydroxychalcones with thallium (III) nitrate trihydrate in methanolic perchloric acid. A hydroxyl group at the C-5 position in isoflavones was necessary for strong attraction to A. euteiches zoospore. The introduction of an additional hydroxyl group at the C-7 or C-4' position strengthened the attracting activity. Moreover, the methylation of the C-7 hydroxyl group strengthened the attracting activity, but the methylation of the C-4' hydroxyl group slightly weakened it. The naturally occurring isoflavones (9 and 10), which were reported to possess estrogen activity, showed moderate attracting activity.

Chalcone↗
PubMed1993

Structures of mefenamic acid metabolites from human urine.

Three major metabolites of mefenamic acid were isolated from the urine of a normal adult man receiving mefenamic acid orally. The structures of those metabolites were determined as glucuronides of mefenamic acid, its hydroxymethyl derivative, and its carboxylic acid derivative on the basis of spectral data.

Adult↗
PubMed1993

Alteration of hepatic DNA synthesis in rats treated with N-nitrosodimethylamine during early stages of copper deficiency.

The main aim of this research was to clarify that nutritional dietary copper may participate in the protective action against hepatocarcinogenesis in rats by N-nitrosodimethylamine (NDMA). The copper concentrations in serum and liver from 2 to 8d after rats were first fed a copper deficient diet (copper, 0.6 ppm) decreased significantly compared to those of pair-fed rats (copper in a control diet, 7 ppm). The subcellular distribution of copper in the liver at 5d after feeding of a copper deficient diet began was measured and the copper concentrations in soluble and nuclear fractions decreased at a similar rate in copper deficient rats treated with or without NDMA, compared to those of pair-fed rats. The incorporation of [3H]thymidine into rat liver DNA at 48 h after treatment with NDMA markedly increased under the experimental conditions used. By giving rats a copper deficient diet for a few days the increased incorporation of [3H]thymidine into liver DNA of rats treated with NDMA was enhanced compared to that of pair-fed rats treated with NDMA. The activity of thymidine kinase in liver of copper deficient rats treated with NDMA was also found to increase significantly compared to that of pair-fed rats treated with NDMA.

Animals↗