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I Miura

Publications and source records attributed to I Miura.

At least 19 recordsLinked to original sources
PubMed1992

Cloning and sequencing of the cDNA encoding tyrosinase of the Japanese pond frog, Rana nigromaculata.

We cloned and sequenced the cDNA encoding tyrosinase (TYN) of the Japanese pond frog, Rana nigromaculata. The 3511-bp cDNA contained a 54-bp 5'-noncoding region, a 1596-bp open reading frame encoding TYN of 532 amino acids (aa), and a 1861-bp 3'-noncoding region. The aa sequence of frog TYN predicted from the cDNA sequence was homologous to that of mouse and human TYNs. The aa sequence including the copper-binding domain, which is likely the active center of TYN, was highly conserved among these three species and Neurospora crassa, Streptomyces antibioticus, and S. glaucescens. The frog TYN also contains possible glycosylation sites and conserved Cys at sites similar to those in the mouse and human TYNs. There are two hydrophobic regions at the N-terminus and near the C-terminus, which are likely the signal (leader) peptide and a transmembrane domain, respectively.

Amino Acid Sequence↗
PubMed1992

Chromosome alterations in human small cell lung cancer: frequent involvement of 5q.

Deletions of the 3p chromosome region and molecular alterations of the tumor suppressor genes RB1 and TP53, located, respectively, at 13q14 and 17p13, are well-documented in small cell lung cancer (SCLC). Because of technical difficulties, karyotypes of primary SCLC specimens are rarely reported. In this study, detailed cytogenetic analysis was performed on 13 early passage SCLC cell lines and fresh specimens, including 4 lung primaries. Numerous chromosome alterations were found, even in newly diagnosed primary tumors. Consistent with previous molecular studies, chromosomal losses of 3p (13 cases) and 17p13 (12 cases) were frequently observed. Numerical losses of chromosome 13 and structural rearrangements affecting 13q14 were identified in 10 specimens. In addition, losses of chromosome 5 and structural alterations of 5q occurred in 12 tumors; among these, 9 displayed losses of region 5q13-q21. Double minutes were found in 4 cases (3 of 5 specimens from patients who received prior cytotoxic therapy but only 1 of 8 from untreated patients). DNA analysis revealed amplification of either MYC1 or MYCN in cells from each of these 4 tumors. Overall, the cytogenetic findings underscore that progression of SCLC involves multiple genetic changes and suggest further that a tumor suppressor gene(s) on 5q may contribute to SCLC tumorigenesis.

Carcinoma, Small Cell↗
PubMed1992

Protective effect of carteolol, a beta-blocker, on myocardial cellular damage in ischemic and reperfused pig hearts: assessment with gated in vivo 31-phosphorus magnetic resonance spectroscopy and electron microscopy.

To assess the effect of carteolol, a beta-blocker, on ischemia and reperfusion, changes in the ultrastructure of myocytes and energy metabolism were studied by 31P-NMR in 41 pig hearts without collateral circulation. The left anterior descending coronary artery was occluded for 20 min and reperfused for 120 min in three groups: seven pigs (group 1, no treatment with carteolol; group 2, pre-ischemia treatment with carteolol (10 micrograms/kg); group 3, post-ischemia treatment with carteolol before reperfusion). Other groups of five pigs were killed after 120 min of ischemia (group 4, no treatment; group 5, pre-ischemia treatment) or 20 min of ischemia (group 6, no treatment; group 7, pre-ischemia treatment). After 20 min of ischemia, ATP was higher in groups 2 (76 +/- 9% of the baseline value) than in group 1 (59 +/- 5%) and group 3 (60 +/- 10%). However, the difference disappeared after 30 min of ischemia. After 120 min of reperfusion, ATP showed much better recovery in group 2 (92 +/- 9%) than in groups 1 (66 +/- 7%) and 3 (68 +/- 10%). Ischemic injury, as viewed by light and electron microscopy, was milder in group 7 than in group 6 after 20 min occlusion, but the myocytes were almost normal after 120 min reperfusion in groups 1 to 3. The heart rate, blood pressure and rate pressure product showed no significant difference among the groups. These results indicate that pre-ischemia treatment with carteolol provided protection against ischemic cellular injury and accelerated the repletion of ATP during reperfusion, but the post-ischemia treatment did not lead to recovery of ATP. Therefore, the favorable effect during reperfusion of pre-ischemia treatment with carteolol depends on its protective effect during ischemia.

Adenosine Triphosphate↗
PubMed1992

Reversibility of energy metabolism and intracellular pH after cerebral ischaemia evaluated by 31P-MRS.

We have previously developed a reproducible model of transient forebrain ischaemia in rats by bilateral carotid artery occlusion combined with temporary increase of ICP. With this model, reversibility of the energy metabolism and intracellular pH (pHi) was investigated by 31P-MRS during 120 min of recirculation in three groups of, respectively, 30, 60, and 120 min of ischaemia. With the induction of ischaemia, ATP and phosphocreatine (PCr) disappeared, and measurement of pHi showed severe acidosis in all rats. In the 30 min ischaemia group, both energy metabolism and pHi recovered almost completely. In the 60 min ischaemia group, ATP recovered to 74% of control values, but pHi showed full recovery. In the 120 min ischaemia group, ATP recovered to about 50% of control values, and recovery of pHi was variable. Showing logarithmical changes during recirculation in ATP and PCr, the rate of metabolic recovery was fast during 60 min of recirculation, but it decreased and reached plateau thereafter in all groups. Recovery of pHi was affected by ATP levels, and was precipitously accelerated as ATP levels exceeded 50% of pre-ischaemic values. These results suggest that prolongation of the duration of ischaemia limits the restoration of the energy state, and the quality of pHi recovery after cerebral ischaemia is affected by the degree of ATP recovery during 60 min of recirculation.

Adenosine Triphosphate↗
PubMed1992

Effects of adenosine on cardiac performance and phosphate compounds in microembolised guinea pig hearts.

OBJECTIVE: The excessive release of adenosine has been reported to cause hyperaemia and to attenuate ischaemic injury in microembolised hearts. The direct effects of exogenous adenosine on cardiac performance were investigated in microembolised guinea pig hearts with the simultaneous measurement of phosphate compounds. METHODS: 21 male guinea pig hearts were perfused according to the Langendorff technique and microembolism was induced by injecting microspheres. Hearts were then treated as follows: group A, adenosine 20 microM and theophylline 60 microM; group B, theophylline 60 microM; group C, saline (control). Cardiac performance was monitored and phosphate compounds were measured by 31P magnetic resonance spectroscopy. RESULTS: Group A showed a significant increase in the left ventricular developed pressure and coronary flow, and a modest restoration of ATP content. Pi/(Pi+Pcr) remained virtually constant. There were no significant changes in left ventricular developed pressure or coronary flow in groups B and C. There was a gradual decrease in tissue ATP content and slight increase in Pi/(Pi+Pcr). CONCLUSIONS: Adenosine improved cardiac performance without adverse effect on energy metabolism in microembolised hearts. Adenosine also restored the ATP stores in microembolised hearts. (Pi = inorganic phosphate; Pcr = phosphocreatine.)

Adenosine↗
PubMed1992

Assessment of liver graft function after cold preservation using 31P and 23Na magnetic resonance spectroscopy.

We investigated the functional damages of the cytoplasm and the cell membrane of liver grafts in male Wister Kyoto rats after 24-hr and 48-hr cold preservations using the University of Wisconsin solution in vitro. Fructose (10 mM) or NH4Cl (50 mM) was added to the perfusate, and synthesis of fructose-1-phosphate (F-1-P) and Na- and H-ion transports through the cell membrane were evaluated by magnetic resonance spectroscopy (MRS), 31P-MRS and 23Na-MRS. After 30 min of reperfusion, beta-ATP/(inorganic phosphate: Pi) of the 48-hr preserved group was significantly lower than the control group and the 24-hr preserved group. The changes of F-1-P in the control group and the 24-hr preserved group were almost the same, but F-1-P synthesis was lower in the 48-hr preserved liver than those of the other groups. Intracellular pH began to drop after the cessation of NH4Cl loading, and then it recovered to the preloading level. At the same time Nain+ was increased in the control group. However, in the other two groups, the increasing rates of Nain+ were lower, and the recoveries of Nain+ were less. In conclusion, the function of cell membrane was more fragile than that of mitochondria and cytoplasmic sugar metabolism in the liver graft.

Adenosine Triphosphate↗
PubMed1992

Metabolism of tegafur in rat liver observed by in vivo 19F magnetic resonance spectroscopy and chromatography.

Metabolism of tegafur in the rat liver was observed by in-vivo 19F magnetic resonance spectroscopy (MRS). After MRS observation, tegafur and q-fluorouracil (5-FU) in the liver were determined by a chromatographic method for comparison with the results of 19F-MRS. Rats were divided into 3 groups: 1) CCl4-induced liver injury group, 2) uracil combined group, 3) control group. Catabolism to fluoro-beta-alanine was suppressed in both the liver injury group and the uracil combined group. Low peaks of 5-FU and fluoronucleotides could be found only in the uracil combined group. The result of 19F MRS observation of each group was in agreement with the result of determination of tegafur and 5-FU by chromatography. This showed that substances which could be observed by 19F-MRS were in proportion to all intracellular fluoro-containing substances. 19F-MRS can provide direct information on the metabolism of fluoropyimidines non-invasively and it might be a useful aid in choosing suitable chemotherapy for patients.

Alanine Transaminase↗
PubMed1992

Comparison of acetate utilization among strains of an aceticlastic methanogen, Methanothrix soehngenii.

The kinetics of acetate utilization by concentrated suspensions of cells was examined in five strains of Methanothrix soehngenii. The rate of acetate utilization by all strains was dependent on the initial acetate concentration and followed simple Michaelis-Menten kinetics. The ability to utilize acetate differed among the various strains of M. soehngenii and was highest in the strain designated MTAS.

Acetates↗
PubMed1992

Effects of anti-epileptic drugs on the L-tryptophan binding to human serum albumin.

Effects of four anti-epileptic drugs (AED; phenobarbital, phenytoin, carbamazepine and sodium valproate) on the L-tryptophan binding to human serum albumin were studied. Among these drugs examined, only sodium valproate inhibited the binding even within the concentrations of its therapeutic range, and the Klotz plotting analysis revealed that the inhibition was competitive. The results of examinations with sera from epileptic patients medicated with these AED and drug-free normal controls also suggested that the protein binding ratios of L-tryptophan were decreased in the blood plasma of some patients with the high valproate concentrations and the low albumin contents.

Anticonvulsants↗
PubMed1992

[Assessment of liver graft function after cold preservation using 31P and 23Na NMR spectroscopy].

We investigated the functional damages of cytoplasm and cell membrane of liver grafts in male WKY rats after 24hr- or 48hr-cold preservation using a UW solution in vitro. 10mM fructose or 50mM NH4Cl was added to the perfusate, and synthesis of fructose-1-phosphate (F-1-P) and Na(+)- and H(+)-ion transports through the cell membrane were evaluated with 31P-MRS and 23Na-MRS. After 30 minutes of reperfusion, beta-ATP/(inorganic phosphate: Pi) of the 48hr-preserved liver was significantly lower than those of the other groups. In the control and the 24hr-preserved liver, the changes of F-1-P were almost the same, but F-1-P synthesis was lower in the 48hr-preserved liver than those of the other groups. Intracellular pH began to drop after cessation of NH4Cl loading, and then recovered to the previous level. At the same time Nain was increased in the control group. However, in the other two groups, the increasing rates of Nain were lower, and the recoveries of Nain were worse. In conclusion, the function of cell membrane was more fragile than that of mitochondria and cytoplasmic sugar metabolism in the liver graft.

Adenosine Triphosphate↗
PubMed1992

In vivo 19F MR spectroscopic study of metabolism of 5-fluorotryptophan in rat liver.

The metabolism of 5-fluorotryptophan in rat liver was examined by in vivo 19F MR spectroscopy. After i.v. injection of 200 mg/kg b.w. of 5-fluorotryptophan the substance was noted immediately as a strong peak, which decreased gradually. Another peak appeared about 40 min after the injection. The chemical shift value of this peak was 1.6 ppm from that of 5-fluorotryptophan. Kynurenine is known to be a major metabolite of tryptophan in the liver. We synthesized 5-fluorokynurenine from 5-fluorotryptophan by ozonolysis. The chemical shift value of 5-fluorokynurenine was confirmed to be coincident with that of the metabolite peak. This strongly suggests that the metabolite peak of 5-fluorotryptophan observed in this study was the 5-fluorokyrurenine signal. We also applied this method for the CCl4-injured liver. In the liver injury group, the metabolite peak appeared slowly and the intensity was low compared to that of the normal group, though the peak of 5-fluorotryptophan decreased similarly as in the normal liver. These results suggest that the decrease of 5-fluorotryptophan is due mainly to the renal excretion, as the injured liver could not metabolize 5-fluorotryptophan.

Animals↗
PubMed1991

Correlation of model chromosome number of cultured non-small cell lung carcinomas with DNA index of solid tumor tissue.

The modal chromosome number of 13 non-small cell lung carcinomas placed into culture was compared to the DNA index of the tumor tissue as measured by flow cytometry in order to determine whether cytogenetic results from such cultures are representative of the original solid tumor. The modal chromosome number observed in culture, which ranged from 45-146, fell within the range of aneuploidy predicted from the DNA content of the original tissue in all 13 cases. In 7 cases, flow cytometry results showed that the aneuploid G1/G0 population of the tumor tissue (DNA index of 1.5 or higher) represented 11-76% of the cells present, while diploid cells (presumably normal tissue) made up the remainder of the population. In these 7 cases, modal chromosome numbers of 61-92 were found in tumor cells cultured from the tissue. In 3 cases, only a diploid or near-diploid population was found by flow cytometry, consistent with the near-diploid modal chromosome number of cultured cells observed (45-55). In 3 cases, the aneuploid G1/G0 population (DNA index of 1.5, 1.6, and 3.2) of the original tissue represented only a small fraction of the solid tumor (1-5% of cells). Modal chromosome number found in cells cultured from these 3 cases was 64-69, 62-68, and 136-146, which is in close agreement with the aneuploid peak observed in the tissue. Histological analysis of the tumor tissue in two of the latter cases showed large numbers of infiltrating lymphocytes and/or stromal tissue which could have dominated the measurement by flow cytometry. In the third case, tumor cells made up at least 75% of the specimen examined, implying that part of the population in the "diploid" peak contained tumor cells in this specimen. Only the aneuploid population was detected in culture of this tumor. Agreement between flow cytometry and cytogenetics was found in cases in which metaphase spreads were obtained within a few days of culture as well as after several months. These results indicate that highly aneuploid populations are found in many, but not all, non-small cell lung tumors. Although in some cases multiple populations may exist in the tumor which do not all proliferate in vitro, tumor cells which are found in culture of solid lung carcinomas are representative of the original tumor. Flow cytometry findings in the solid tumors confirmed the findings of aneuploidy observed by cytogenetic analysis.

Aneuploidy↗
PubMed1991

The endoscopic and surgical management of portal hypertension in children: analysis of 123 cases.

Since 1973, 178 children with portal hypertension (PH) have been seen at Instituto da Criança of the University of São Paulo Medical School. Fifty-five of these children were excluded from this analysis for various reasons, including no treatment required, death before treatment, or incomplete data. From the remaining 123 children with esophageal varices, only 96 (76.1%) of them had at least one episode of upper gastrointestinal hemorrhage. Eighty-eight children were submitted to injection sclerotherapy; 26 treated prophylactically, and 62 for treatment of previous bleeding. Eleven (42.3%) children from the prophylactic group bled from esophageal varices during the treatment. They were all successfully managed thereafter. Satisfactory results were achieved in 53 (85.4%) children in the therapeutic group. Twenty-eight (45.1%) children had at least one episode of bleeding after beginning of sclerotherapy, 19 of whom eventually had successful control of the variceal bleeding. From 1973 to 1984, distal splenorenal shunt (DSS) was the procedure of choice for the treatment of bleeding esophageal varices. Forty-two children have undergone DSS during this period. Only one child was shunted prophylactically. Since 1985, injection sclerotherapy has been the first choice for the treatment and only seven children with sclerotherapy failure have since been treated by DSS. Characteristically these children had very similar splenoportographic pattern with huge esophageal and gastric varices and deviation of portal vein blood flow toward the left gastric vein.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

The inhibitory effect of bevantolol on the accumulation of non-esterified fatty acids during ischaemia in the dog heart in situ.

1. The left anterior descending coronary artery (LAD) was completely ligated for 90 min (i.e. myocardial ischaemia was produced) in the dog anaesthetized with pentobarbital. 2. Bevantolol, a beta 1-adrenoceptor antagonist, was injected (1 mg/kg, intravenously) 5 min before LAD occlusion. The bevantolol injection decreased heart rate without affecting blood pressure. 3. The myocardial samples were taken from the LAD area immediately after the end of LAD occlusion, and were subjected to analysis of the myocardial levels of non-esterified fatty acids (NEFA). 4. In dogs in which saline was injected, ischaemia produced accumulation of NEFA, especially arachidonic and palmitoleic acids, in the myocardium. 5. In dogs in which bevantolol was injected, the accumulation of NEFA induced by ischaemia was almost completely inhibited. 6. It is concluded that bevantolol inhibits ischaemia-induced accumulation of NEFA in the myocardium, and that stimulation of the beta 1-adrenoceptors is probably responsible for NEFA accumulation induced by ischaemia.

Adrenergic beta-Antagonists↗
PubMed1991

Ischemic preconditioning preserves creatine phosphate and intracellular pH.

BACKGROUND: Ischemic preconditioning slows ATP depletion and ultrastructural damage during the final episode of ischemia. To define the influence of creatine phosphate (CP) and intracellular pH (pHi) on this effect, CP and pHi were serially measured in porcine hearts without collateral circulation by using 31P-NMR spectroscopy and ultrastructural examination. METHODS AND RESULTS: Farm pigs weighing 12-15 kg were anesthetized with Fluothane. The control group underwent a single occlusion (20 minutes or 60 minutes); the preconditioned group underwent four episodes of 5-minute occlusion and 5-minute reperfusion followed by a sustained occlusion (20 minutes or 60 minutes). After ischemic preconditioning, CP increased to 115 +/- 11% (p less than 0.05) of preischemic value and ATP decreased to 84 +/- 8% (p less than 0.05) of preischemic value, but pHi returned to preischemic value. At 5 and 10 minutes of sustained ischemia, CP was significantly preserved in the preconditioned group (control group, 19 +/- 3% versus preconditioned group, 29 +/- 4% at 5 minutes; control group, 5 +/- 3% versus preconditioned group, 11 +/- 3% at 10 minutes; p less than 0.05). At 15 and 20 minutes of sustained ischemia, ATP was significantly preserved in the preconditioned group (control group, 64 +/- 3% versus preconditioned group, 73 +/- 3% at 15 minutes; control group, 51 +/- 7% versus preconditioned group, 62 +/- 2% at 20 minutes; p less than 0.05). At 10, 15, 20, and 25 minutes of sustained ischemia, pHi was significantly higher in the preconditioned group (control group, 6.5 +/- 0.05 versus preconditioned group, 6.7 +/- 0.1 at 10 minutes; control group, 6.3 +/- 0.05 versus preconditioned group, 6.6 +/- 0.06 at 15 minutes; control group, 6.1 +/- 0.1 versus preconditioned group, 6.4 +/- 0.1 at 20 minutes; control group, 6.0 +/- 0.2 versus preconditioned group, 6.3 +/- 0.1 at 25 minutes; p less than 0.05). Ultrastructural changes were milder in the preconditioned group at 20 minutes of sustained ischemia. CONCLUSIONS: In addition to ATP and ultrastructure, preconditioning preserved CP and pHi during sustained ischemia. These protective effects might be due to overshoot phenomenon of CP and/or reduced ATP consumption. The relatively longer period of preservation of pHi, which probably is the result of reduced ATP consumption, indicates its greater contribution to reducing infarct size than that of CP and ATP.

Adenosine Triphosphate↗
PubMed1991

Changes in the plethysmogram patterns of finger reactive hyperemia in nutritional (alcoholic) liver disease patients with increased serum monoamine oxidase activities.

The activity levels of serum monoamine oxidase in nutritional (alcoholic) liver disease patients were elevated beyond the upper normal limit, while those of other subjects without pathologically accelerated fibrosis ranged within normal values. Capillaroscopic and plethysmographic studies on finger reactive hyperemia revealed that two characteristic changes in the blood microcirculation, which indicated an occurrence of increased fibritic process in the capillary wall and skin tissues, were observed only in the nutritional (alcoholic) liver disease patients with the elevated serum monoamine oxidase levels. These results suggested that nutritional (alcoholic) liver disease is not a disease restricted to liver tissues, but to a disorder creating pathological fibrosis in the whole-body.

Adolescent↗