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Biomedical subjects

Y Nagamura

Publications and source records attributed to Y Nagamura.

At least 37 records · Page 2Linked to original sources
PubMed1998

Ethanolamine stimulates repair processes in acute CCl4 damage of mouse liver.

Ethanolamine, a positively charged hydrophilic component of the phosphatidylethanolamine (PE) which is also a precursor of phosphatidylcholine (PC), enhances the repair processes 24 h after carbon tetrachloride (CCl4) intoxication of mouse liver. Ethanolamine quickly reduced aminotransferase activity released in the serum, increased the hepatocellular nuclear BrdU uptake, a marker of S phase, and the epidermal growth factor (EGF) receptor content in the liver injured with CCl4. Thus, exogenous administration of ethanolamine may function as a liver proliferating factor in CCl4 intoxicated mouse liver.

Alanine Transaminase↗
PubMed1998

12(S)-HETE plays a role as a mediator of expression of platelet CD62 (P-selectin).

The role of 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid (12(S)-HETE), an abundant lipoxygenase product from arachidonic acid in platelets, remains unknown. We investigated and characterized the role of 12(S)-HETE in platelet activation. 12(S)-HETE production and CD62 expression were increased by stimulation with thrombin at 0.03 U/ml or higher, while TXB2 synthesis was increased by thrombin at 0.1 U/ml or higher. The platelet 12(S)-HETE production was increased 10 s after stimulation and this was earlier than CD62 expression. The expression of CD62 was inhibited by the lipoxygenase (LOX) inhibitors quercetin and nordihydroguaiaretic acid but was not affected by the cyclooxygenase (COX) inhibitors aspirin and indomethacin. Exogenously added 12(S)-HPETE and 12(S)-HETE enhanced CD62 expression, but other HETEs did not. Consequently, 12-LOX products play a role in the expression of CD62 and could be a second messenger for platelet activation.

Journal Article↗
PubMed1998

A high-density rice genetic linkage map with 2275 markers using a single F2 population.

A 2275-marker genetic map of rice (Oryza sativa L.) covering 1521.6 cM in the Kosambi function has been constructed using 186 F2 plants from a single cross between the japonica variety Nipponbare and the indica variety Kasalath. The map provides the most detailed and informative genetic map of any plant. Centromere locations on 12 linkage groups were determined by dosage analysis of secondary and telotrisomics using > 130 DNA markers located on respective chromosome arms. A limited influence on meiotic recombination inhibition by the centromere in the genetic map was discussed. The main sources of the markers in this map were expressed sequence tag (EST) clones from Nipponbare callus, root, and shoot libraries. We mapped 1455 loci using ESTs; 615 of these loci showed significant similarities to known genes, including single-copy genes, family genes, and isozyme genes. The high-resolution genetic map permitted us to characterize meiotic recombinations in the whole genome. Positive interference of meiotic recombination was detected both by the distribution of recombination number per each chromosome and by the distribution of double crossover interval lengths.

Chromosome Mapping↗
PubMed1998

The effect of ethanolamine on acute carbon tetrachloride intoxication.

The effects of ethanolamine on injured liver were investigated by oral administration of ethanolamine to male ddY mice 24 h after carbon tetrachloride (CCl4) injection. The serum aminotransferase activities in mice with liver injury were reduced by ethanolamine treatment (10-30 mg/kg body weight). Drastically increased regenerative reaction of ethanolamine treated-CCl4 injured liver was also observed through an increase in 5-bromo-2'-deoxyuridine uptake. ATP concentration in liver tissue was recovered by administration of ethanolamine. These results suggest that oral administration of ethanolamine accelerates recovery from CCl4-induced liver injury.

Adenosine Triphosphate↗
PubMed1998

The recovering effect of betaine on carbon tetrachloride-induced liver injury.

The recovering effect of betaine (derivative of choline) on carbon tetrachloride (CCl4)-injured liver was investigated by oral and intraperitoneal administration of betaine at 24 h after acute CCl4 intoxication. The effect of betaine was estimated by the activity of alanine aminotransferase (ALT) released into the serum, histological score, and the incorporation of S-phase indicator (5-bromo-2-deoxyuridine/5-fluoro-2'-deoxyuridine; BrdU/FdU). A significant decrease in the activity of serum ALT was observed by the intraperitoneal (3 mg/kg body) or oral (15 mg/kg body) administration of betaine. Furthermore, an increase in the uptake of BrdU into the hepatocyte nuclear DNA and a reduction in liver necrosis after the oral treatment of betaine (15 mg/kg body) was observed. From these results, the administration of betaine showed a significant effect in recovering CCl4-injured liver.

Alanine Transaminase↗
PubMed1997

Early detection of successful coronary reperfusion based on serum concentration of human heart-type cytoplasmic fatty acid-binding protein.

Both human heart-type cytoplasmic fatty acid-binding protein (H-FABPc) and myoglobin are low molecular weight proteins that are abundant in the cytoplasm of myocardial cells. Unlike myoglobin, H-FABPc content in the skeletal muscle is less than in cardiac muscle. To investigate the usefulness of the serum concentration of H-FABPc in the early detection of successful coronary reperfusion, we measured serum concentrations of H-FABPc and myoglobin in 45 patients with acute myocardial infarction treated with intracoronary thrombolysis or direct percutaneous transluminal coronary angioplasty. Coronary angiography was performed every 5 min for reperfusion therapy to identify the onset of reperfusion. Reperfusion, defined as a TIMI grade 2 or 3, was achieved within 60 min of the initiation of reperfusion therapy in 30 patients (the reperfused group), but was not achieved in 15 patients (the non-reperfused group). Blood samples were obtained before initiation of treatment and 15, 30 and 60 min after initiation of treatment in the non-reperfused group. In the reperfused group, samples were obtained before reperfusion and 15, 30 and 60 min after reperfusion. The H-FABPc ratio (the ratio of value after to value before the initiation of treatment or reperfusion) increased sharply after the onset of reperfusion, peaking at 41 +/- 18 min, and decreased rapidly thereafter. The predictive accuracy of an H-FABPc ratio of > 1.8 for the detection of reperfusion within 60 min of the initiation of treatment was 93% at 15 min after reperfusion, 98% at 30 min, and 100% at 60 min. Similar rates of predictive accuracy were observed for a myoglobin ratio > 2.4. The H-FABPc ratio detected successful reperfusion as early as 15 min after the onset of reperfusion and was highly accurate in detecting reperfusion within 60 min of the onset of reperfusion. The predictive accuracy of the H-FABPc ratio was similar to that of the myoglobin ratio for the early detection of successful coronary reperfusion.

Adult↗
PubMed1997

Serum concentrations of myoglobin vs human heart-type cytoplasmic fatty acid-binding protein in early detection of acute myocardial infarction.

We compared the diagnostic utility of serum concentrations of human heart-type cytoplasmic fatty acid-binding protein (H-FABPc), myoglobin, and their ratio for the early diagnosis of acute myocardial infarction (AMI) in 104 healthy volunteers and 165 patients at admission within 6 h of the onset of chest pain. The ROC curves of the H-FABPc [0.946, 95% confidence interval (CI) = 0.913-0.979] and myoglobin (0.895, 95% CI = 0.846-0.944) between patients with AMI and healthy volunteers were significantly greater than the area under the ratio of myoglobin to H-FABPc (0.823, 95% CI = 0.765-0.881). In 165 patients, the sensitivity (81.8%, 95% CI = 74.2-89.4%), specificity (86.4%, 95% CI = 78.1-94.6%), and predictive accuracy (83.6%, 95% CI = 78.0-89.3%) of H-FABPc > 12 micrograms/L in diagnosing AMI were significantly higher than those of myoglobin, and were similar to those of the combination of H-FABPc > 12 micrograms/L and the ratio < or = 14. We conclude that H-FABPc is a more sensitive and specific marker than myoglobin for the early diagnosis of AMI, and that their ratio cannot give a clear advantage over the measurement of H-FABPc alone.

Adult↗
PubMed1997

Rice molecular genetic map using RFLPs and its applications.

In the past decade, notable progress has been made in rice molecular genetic mapping using genomic or cDNA clones. A total of over 3000 DNA markers, mainly with RFLPs, have been mapped on the rice genome. In addition, many studies related to tagging of genes of interest, gene isolation by map-based cloning and comparative mapping between cereal genomes have advanced along with the development of a high-density molecular genetic map. Thus rice is considered a pivotal plant among cereal crops and, in addition to Arabidopsis, is a model plant in genome analysis. In this article, the current status of the construction of rice molecular genetic maps and their applications are reviewed.

Genetic Markers↗
PubMed1996

Conversion of gamma-glutamylcysteinylethyl ester to glutathione in rat hepatocytes.

The conversion of gamma-glutamylcysteinylethyl ester (gamma-GCE) to glutathione in a reduced form (GSH) was examined using isolated rat hepatocytes pretreated with diethylmaleate, a GSH-depletor. Incubation of hepatocytes with 0.1 and 5.0 mM gamma-GCE (gamma-GCE-hepatocytes) over a 30-min period resulted in time-dependent increases in intracellular GSH and nonprotein-SH (NP-SH) concentrations. Hepatocytes incubated with 5.0 mM but not 0.1 mM GSH over a period of 30 min showed a time-dependent increase in intracellular GSH concentration. In the gamma-GCE-hepatocytes pretreated with bis-(p-nitrophenyl)phosphate (BNPP), a non-specific esterase inhibitor, an enhancement of intracellular GSH concentration was markedly reduced. gamma-GCE concentration in the gamma-GCE-hepatocytes with BNPP pretreatment was significantly higher than that in the cells without BNPP pretreatment, although there was no difference in the total amount of intracellular NP-SH, i.e., gamma-GCE, GSH, gamma-glutamylcysteine, cysteine ethyl ester, and cysteine between both gamma-GCE-hepatocytes. The present results indicate that gamma-GCE is transported into liver cells more easily than GSH itself, resulting in its conversion to GSH via esterase and glutathione synthetase within the cells.

Animals↗
PubMed1996

Characterization of cDNA encoding for phosphoglucose isomerase of rice (Oryza sativa L.).

Two types of genes (Pgi-a and Pgi-b) encoding phosphoglucose isomerase (PGI; EC 5.3.1.9) were cloned from cDNA libraries of rice cultured cells (Oryza sativa L.). Pgi-a and Pgi-b consisted of 2132 and 2030 nucleotides, respectively. The homology between these genes was 93.0% at nucleotide level. The homology scores between these genes in protein coding region and 3' non-coding region were 95.6% and 79.4%, respectively. PGI proteins encoded by Pgi-a and Pgi-b consisted of 567 and 568 amino acid, respectively, sharing 95.8% homology at amino acid sequences. Of 11 PGI genes from other plant species and organisms whose amino acid sequences had been determined, a dicotyledonous plant Clarkia lewisii PGI showed the highest homology (about 80%) with rice PGIs. GC contents at the third position of rice PGI genes were about 40%. In order to confirm the enzyme activity of the protein encoded by the rice cDNA, Pgi-a was subcloned into an expression vector, pBluescript II SKp, which was introduced into Escherichia coli. The transformant had an additional PGI activity from Pgi-a.

Amino Acid Sequence↗
PubMed1995

cDNA sequences of three kinds of beta-tubulins from rice.

Complete nucleotide sequences of three kinds of rice beta-tubulin cDNA clones (pTUB22, R1623 and R2242) were determined. Southern hybridization indicated that these beta-tubulins consist of one gene family. Using RFLP mapping, these three beta-tubulin cDNAs were mapped to different chromosomes indicating at least three loci for the beta-tubulin gene. The deduced amino acid sequences of these cDNAs showed a high similarity to other plant beta-tubulins. The asparagine residue located at the 100th amino acid from the N-terminus of plant beta-tubulins was also conserved with these three beta-tubulins. This asparagine is thought to be responsible for the sensitivity against rhizoxin, the toxin of the pathogen of rice seedling blight, Rhizopus sp. a soil-borne microorganism. Expression of the three beta-tubulin genes was analyzed by Northern blotting and all three clones were expressed in root, the possible target tissue of rhizoxin. These results suggest that these clones are candidates of beta-tubulins targeted by rhizoxin.

Amino Acid Sequence↗
PubMed1995

Genomic organization of 57 ribosomal protein genes in rice (Oryza sativa L.) through RFLP mapping.

Four hundred cDNA clones from rice (Oryza sativa L.) callus and root cDNA libraries, with a high similarity to about 70 kinds of ribosomal proteins (r-protein) in eukaryotic as well as procaryotic organisms, were identified by their deduced amino acid sequences. Southern hybridization of 114 independent cDNA clones with total rice genomic DNA showed 77 distinct and specific hybridization patterns. Of the 77 clones representing the above hybridization patterns, copies of 67 clones corresponding to 57 r-proteins could be estimated and, among these, only 6 clones were single copy, indicating that almost 90% of these r-proteins in rice were encoded by small multigene families. Loci of 36 r-protein genes could be mapped on the rice linkage map by using 30 full-length cDNA clone sequences from specific RELP bands. Another 21 expressed gene loci were mapped using 3' untranslated region specific cDNA probes amplified from the multicopy cDNA clones representing 17 of the r-protein multicopy gene families. The above 57 loci were mapped from 51 cDNA clones and 41 of these r-protein genes mapped to regions that did not show any clustering, while in 5 cases, pairs of r-protein genes cosegregated or linked closely. The r-protein genes in rice were located throughout the 12 chromosomes and it was found that more than one copy within a multigene family may be expressed simultaneously.

Base Sequence↗
PubMed1995

Stenosis enhances role of platelets in growth of regional thrombus and intimal wall thickening in rat carotid arteries.

The authors present the results of a study in which stenosis was induced, resulting in either thrombus or intimal wall thickening, in rat carotid arteries. At > or = 75% stenosis in mildly denuded arteries, an acute and occlusive thrombus formation was induced, but the thrombus was significantly reduced in thrombocytopenia. Thrombus formation near the site of stenosis decreased with decreasing degree of stenosis, whereas the percent formation in the distal region (percent total thrombus) increased. Numerous mural platelet microthrombi were noted at the distal region of the stenosed arteries. After chronic 50% stenosis of the carotid artery for 2 weeks, significant intimal thickening was observed, without any occlusive thrombus formation. The combination with mild denudation was critical in eliciting the effect of stenosis. The magnitude of intimal growth in the stenosed artery was marked by day 6 and plateaued thereafter, whereas it was slight in nonstenosed arteries. The 5-bromodeoxyuridine index of the cells of the medial layer at day 3 was significantly increased by the stenosis, and the effect was reversed in thrombocytopenia. Complete reendothelialization of the intimal surface was observed by 7 to 10 days after surgery in the stenosed arteries. These findings suggest that the introduction of stenosis in these arteries enhances the interaction of platelets with the damaged arterial walls under abnormal fluid shear and that this enhancement leads to acute and occlusive thrombus formation associated with more marked stenosis as well as to sustained increase of intimal wall thickness in less marked stenosis.

Animals↗
PubMed1994

A 300 kilobase interval genetic map of rice including 883 expressed sequences.

We have constructed a high resolution rice genetic map containing 1,383 DNA markers at an average interval of 300 kilobases (kb). The markers, distributed along 1,575 cM on 12 linkage groups, comprise 883 cDNAs, 265 genomic DNAs, 147 randomly amplified polymorphic DNAs (RAPD) and 88 other DNAs. cDNAs were derived from rice root and callus, analysed by single-run sequencing and searched for similarities with known proteins. Nearly 260 rice genes are newly identified and mapped, and genomic DNA and cloned RAPD fragments were also sequenced to generate STSs. Our map is the first significant gene expression map in plants. It is also the densest genetic map available in plants and the first to be backed up comprehensively by clone sequence data.

Chromosome Mapping↗
PubMed1994

Cloning and mapping of telomere-associated sequences from rice.

We have isolated three telomere-associated sequences from rice using cassette-ligation-mediated polymerase chain reaction (PCR). Each of the obtained clones hybridized to the terminal of one or several rice chromosome arms. The telomeres recognized by the clones displayed a high level of polymorphism between two rice varieties, Nipponbare (a japonica variety) and Kasalath (an indica variety). Variability in the chromosome termini was also detected among individual F2 progeny plants, which were derived from a cross between the two rice varieties. One clone containing telomere-associated sequences was located to one end of chromosome 5, and another clone to one end of chromosome 11. For another clone, non-allelic segregation of polymorphic hybridization bands was observed between japonica and indica rice; this clone was mapped to one end of chromosome 12 in japonica and to one end of chromosome 11 in indica rice. This indicates an exchange of termini between nonhomologous chromosomes.

Base Sequence↗
PubMed1994

Humoral hypercalcemia of malignancy associated with parathyroid hormone-related protein producing transitional cell carcinoma of the ureter.

A 78-year old male with ureteral carcinoma manifesting hypercalcemia is reported. He was diagnosed as having ureteral carcinoma of the left side 2 years previously and was treated by nephrectomy with ureterovesicostomy. In October 1991, he was admitted for anorexia. A clinical examination revealed recurrence of the ureteral carcinoma with metastasis to the rectum and liver. His serum calcium level was elevated (13.9 mg/dl). In addition to rehydration and furosemide, treatment with eel-calcitonin and prednisolone failed to decrease his serum calcium level. Finally, he was administered mithramycin but he died 13 days later. He had no evidence of bone metastasis or hyperparathyroidism. Nephrogenic cAMP and urinary parathyroid hormone-related protein (PTHrP) were markedly elevated. Immunohistochemical study demonstrated expression of PTHrP in the tumor cells. Thus, the hypercalcemia was thought to be mediated by PTHrP secreted from the neoplastic tumor. Although there have been several reports of ureteral carcinoma associated with humoral hypercalcemia of malignancy, this is considered to be the first case associated with elevation of PTHrP.

Aged↗