Biomedical subjects

K Oda

Publications and source records attributed to K Oda.

At least 271 records · Page 15Linked to original sources

PubMed1995

Role of neutrophils and platelets in the pathogenesis of focal hepatocellular necrosis in endotoxaemia.

To clarify whether neutrophils and platelets are implicated in the pathogenesis of focal hepatocellular necrosis in endotoxaemia, we examined the relationship between the changes in neutrophils and platelets in peripheral blood and the degree of focal hepatocellular necrosis and serum transaminase activity in rats after endotoxin injection. The number of neutrophils in the peripheral blood decreased rapidly during the first hour after endotoxin injection and then increased. This initial decrease might be caused by the adhesion of neutrophils to pulmonary capillary walls, and the subsequent increase might be caused by granulocyte colony-stimulating factor mediated by endotoxin. However, there was no relationship between the degree of focal hepatocellular necrosis and the number of neutrophils sticking to the walls of hepatic sinusoids or the changes in the neutrophil count in the peripheral blood. The number of platelets in the peripheral blood decreased rapidly after endotoxin injection. There was a statistically significant relationship between the number of platelets in the peripheral blood and the level of serum transaminase activity: the fewer the platelets, the more severe was focal hepatocellular necrosis. The present study suggests that rapid and extensive consumption of platelets, rather than neutrophils sticking to the sinusoidal walls, is involved in the pathogenesis of focal hepatocellular necrosis in endotoxaemia.

Animals↗

PubMed1995

Intracellular sorting of lysosomal beta-glucuronidase is altered due to administration of dibutyl phosphate.

Organophosphate compounds are known to cause a selective increase of beta-glucuronidase activity in rat serum. Previous data suggested that increase of serum beta-glucuronidase activity was well correlated with decrease of that activity in rat liver microsomal fraction, thereby, suggesting a role of the microsomal enzyme in mediating the organophosphate effect. To investigate further the intracellular sorting pathway of beta-glucuronidase in dibutyl phosphate-treated rats, liver subcellular fractions were prepared at 12 or 48 h after in vivo administration of [3H]leucine and it was established that microsomal beta-glucuronidase was the origin of the increased serum enzyme. To characterize the intracellular secretory pathway of beta-glucuronidase in dibutyl phosphate-treated rats, Golgi subfractions were isolated and a time course study was carried out. At 30 min after administration of dibutyl phosphate, specific activity of beta-glucuronidase in GF-2 (Golgi intermediate fraction) and GF-3 (Golgi heavy fraction) was significantly increased to the maximum. Furthermore, colchicine pretreatment of rats caused a delay of the peak of specific activity for 30 min in GF-2 and GF-3, and accumulation of enzyme activity in Golgi subfractions was observed. Colchicine pretreatment also had an inhibitory effect on release of beta-glucuronidase into serum until 30 min after dibutyl phosphate injection. The electrophoretic pattern of microsomal beta-glucuronidase on polyacrylamide gel was found to show two major bands of microsomal enzyme type and lysosomal enzyme type in dibutyl phosphate-treated rats. Taken together, these findings indicate that microsomal beta-glucuronidase follows the intracellular secretory pathway and is secreted into serum via Golgi complex in response to dibutyl phosphate.

Animals↗

PubMed1995

The primary structure of pepstatin-insensitive carboxyl proteinase produced by Pseudomonas sp. No. 101.

A unique carboxyl proteinase [EC 3.4.23.33] from Pseudomonas sp. No. 101 is the first example of a prokaryotic enzyme which is insensitive to the classical inhibitor, pepstatin. The primary structure of the proteinase was determined by conventional methods. Pseudomonas carboxyl proteinase consists of 370 amino acid residues with one disulfide bond. This enzyme has no homologous sequence with any other known carboxyl proteinase, including carboxyl proteinase B from Scytalidium lignicolum, which is a pepstatin-insensitive carboxyl proteinase. In addition, Pseudomonas carboxyl proteinase lacks the Asp*-Thr-Gly, Glu*-Thr-Gly, and Asp*-Thr-Ser-Gly (*indicates the catalytic residue) sequences which are known as the motif sequences around a pair of catalytic residues in carboxyl proteinases reported so far. The results strongly indicate that Pseudomonas carboxyl proteinase is a new type of carboxyl proteinase.

Amino Acid Sequence↗

PubMed1995

Plant inositol monophosphatase is a lithium-sensitive enzyme encoded by a multigene family.

myo-Inositol monophosphatase (IMP) is a soluble, Li(+)-sensitive protein that catalyzes the removal of a phosphate from myo-inositol phosphate substrates. IMP is required for de novo inositol synthesis from glucose 6-phosphate and for breakdown of inositol trisphosphate, a second messenger generated by the phosphatidylinositol signaling pathway. We cloned the IMP gene from tomato (LeIMP) and show that the plant enzyme is encoded by a small gene family. Three different LeIMP cDNAs encode distinct but highly conserved IMP enzymes that are catalytically active in vitro. Similar to the single IMP from animals, the activities of all three LeIMPs are inhibited by low concentrations of LiCl. LeIMP mRNA levels are developmentally regulated in seedlings and fruit and in response to light. Immunoblot analysis detected three proteins of distinct molecular masses (30, 29, and 28 kD) in tomato; these correspond to the predicted molecular masses of the LeIMPs encoded by the genes. Immunoreactive proteins in the same size range are also present in several other plants. Immunolocalization studies indicated that many cell types within seedlings accumulate LeIMP proteins. In particular, cells associated with the vasculature express high levels of LeIMP protein; this may indicate a coordinate regulation between phloem transport and synthesis of inositol. The presence of three distinct enzymes in tomato most likely reflects the complexity of inositol utilization in higher plants.

Amino Acid Sequence↗

PubMed1995

A specific chromosome abnormality of t(4;12)(q11-12;p13) in CD7+ acute leukaemia.

Three cases of acute leukaemia with t(4;12) (q11-12;p13) karyotypic abnormalities were analysed. They had the following common clinical and biological characteristics: (1) dysplasia of three haemopoietic lineages: (2) absent or low myeloperoxidase activity: and (3) retention of platelets in the peripheral blood and megakaryocytes in the bone marrow. There were increased numbers of basophils in the bone marrow and peripheral blood in two of the cases. In all, the blast cells displayed the unique immunophenotype CD7+CD13+CD34+HLA-DR+. The blasts analysed in one case expressed c-kit on the membrane surface. These findings suggest that the t(4;12) (q11-12;p13) abnormality is associated with a particular type of acute leukaemia, one in which the morphology and immunophenotype suggest that the translocation may have occurred at an early stage of haemopoiesis.

Acute Disease↗

PubMed1995

Epstein-Barr virus genomes in Hodgkin's disease and non-Hodgkin's lymphomas.

Seventeen of 40 cases of Hodgkin's disease (HD) and eight of 46 non-Hodgkin's lymphomas (NHL) were associated with Epstein-Barr virus (EBV) infection, judged by the EBER-1 in situ hybridization (ISH) method. Approximately 40% incidence in HD was comparable to previous reports. Young children and elderly HD patients were more prone to be found EBV positive. Fourteen of 17 HD and two of 8 NHL cases with positive EBER-1 ISH were also positive on LMP-1 immunostaining. EBV might have a role in lymphomagenesis in these cases. The fact that 7 of 8 EBV-related NHL were peripheral T cell lymphoma indicates the necessity of a larger-scale survey on this subject. As the present study revealed four cases with positive LMP-1 immunostaining but negative EBER-1 ISH (1 HD, 3 NHL), LMP-1 alone should not be regarded as a tool to prove EBV infection.

Adolescent↗

PubMed1995

The RNA polymerase PB2 subunit is not required for replication of the influenza virus genome but is involved in capped mRNA synthesis.

An established cell line, clone 64, in which the expression of the RNA polymerase PB1 and PA subunit genes and the nucleoprotein (NP) gene but not the PB2 subunit gene of influenza virus can be induced by the addition of dexamethasone, was used to analyze the replication and transcription machineries of the influenza virus. Both NS-CATc and NS-CATv, the chimeric nonstructural protein chloramphenicol acetyltransferase (NS-CAT) RNAs in the sense and antisense orientations positioned between the 5'- and 3'-terminal sequences of influenza virus RNA segment 8 (the NS gene), respectively, can be transcribed into the corresponding complementary-strand RNA in clone 64 cells only when treated with dexamethasone. Although sense-strand poly(A)+ CAT RNA was detected in the dexamethasone-treated clone 64 cells transfected with NS-CATv RNA, CAT activity was not detected in these cells and the isolated poly(A)+ CAT RNA was inert in an in vitro translation system. However, when the poly(A)+ CAT RNA was capped by using a purified yeast mRNA capping enzyme (mRNA guanylyltransferase), the capped poly(A)+ CAT RNA became translatable in the in vitro translation system. These results indicated that PB1, PA, and NP can support the replication of the influenza virus genome as well as the transcription to yield uncapped poly(A)+ RNA and that PB2 is specifically required for the synthesis of capped RNA.

Animals↗

PubMed1995

G10BP, an E1A-inducible negative regulator of Sp1, represses transcription of the rat fibronectin gene.

Downregulation of the fibronectin (FN) gene in a rat 3Y1 derivative cell line, XhoC, transformed by the adenovirus E1A and E1B genes seems to be caused by the induction of a negative regulator, G10BP, which binds to three G-rich sequences in the promoter (T. Nakamura, T. Nakajima, S. Tsunoda, S. Nakada, K. Oda, H. Tsurui, and A. Wada, J. Virol. 66:6436-6450, 1992). These are the G10 stretch and two GC boxes consisting of the G10 stretch with one internal C residue insertion. The recognition sequences of G10BP and Sp1 (GGGCGG) overlap in these GC boxes. To analyze the mechanism of the downregulation, G10BP was purified by DNA affinity chromatography, and its molecular mass was estimated to be about 30 kDa. The promoter was modified by substituting the sequence GGGG with ATCC or CTTA in these G-rich sequences, leaving the Sp1 motif intact, and by replacing the Sp1 motif by the T stretch. Transcription of FN promoter-chloramphenicol acetyltransferase fusion genes carrying the base substitution in one or more of these G-rich sequences both in vivo and in vitro revealed that the base substitution in any G-rich sequence results in reduction of promoter activity, although the downstream GC box (GCd) plays a primary role. The addition of G10BP severely inhibited the activities of the FN promoters carrying the wild-type GCd in vitro, while the promoters carrying the mutant GCd were unaffected. The binding affinity of G10BP and Sp1 to each of the G-rich sequences, analyzed by gel shift assays, indicated that G10BP binds strongly to the GCd, moderately to the G10 stretch, and weakly to GCu, while Sp1 binds strongly to GCu, moderately to GCd, and weakly to the G10 stretch. Sp1 binding to GCd and the G10 stretch was inhibited by G10BP, while binding to GCu was unaffected. These results indicate that FN gene transcription is inhibited in XhoC cells primarily by exclusion of Sp1 binding to GCd by G10BP and that G10BP is a new class of Sp1 negative regulator.

Adenovirus E1A Proteins↗

PubMed1995

The G1/S boundary-specific enhancer of the rat cdc2 promoter.

Multiple species of G1 cyclins and cyclin-dependent kinases are induced sequentially during G1 phase, and the expression of cyclin A and cdc2 genes is subsequently induced at the G1/S boundary. To analyze the mechanism of cdc2 promoter activation, the 5'-flanking region of the rat cdc2 gene was isolated and its structural features were characterized. The highly conserved sequence between human and rat cdc2 genes is present in the basal promoter region from positions -183 to -122, which contains the E box, SpI, and E2F motifs. The expression of 5' sequential deletion derivatives of the promoter fused to luciferase cDNA in rat 3Y1 cells revealed the presence of the enhancer element. The presumed enhancer region was further analyzed by the introduction of base substitutions and by the formation of DNA-protein complexes with cell extracts prepared at various times during the G1-to-S-phase progression. These analyses revealed that the enhancer sequence, AAGTTACAAATA, located from -276 to -265, confers strong inducibility on the basal promoter at the G1/S boundary. The base substitutions introduced into the motifs of transcription factors indicated that the E2F motif is essential for the enhancer-dependent activation of the cdc2 promoter at the G1/S boundary. Electrophoretic mobility shift assays and DNase I footprinting showed that a factor which interacts with the enhancer element is induced late in G1 phase.

Animals↗

PubMed1995

Immunohistochemical and biochemical detection of low density lipoprotein receptors in cultured rat mesangial cells.

The expression of low density lipoprotein (LDL) receptors by cultured rat mesangial cells was demonstrated using immunohistochemical and biochemical methods. Using a mouse monoclonal anti-human LDL receptor antibody, the immunofluorescence technique was applied to cultured mesangial cells and showed granular staining. Immunoblotting analysis of the membrane fraction of cultured mesangial cells showed a single band with a protein of approximately 130,000 molecular weight. In addition, [125I]LDL binding and the uptake of [125I]LDL by cultured mesangial cells were studied. Binding and uptake both reached an equilibrium after about 30 min of incubation. A 50% reduction in [125I]LDL (20 micrograms protein/ml) binding and uptake occurred when unlabelled LDL was added to cultures at 20-40 micrograms protein/ml. Addition of high density lipoprotein without apoE to the culture medium did not induce competitive inhibition of [125I]LDL binding and uptake by mesangial cells. These findings suggest that cultured mesangial cells have the capacity to express an LDL receptor that regulates the cellular uptake of LDL.

Animals↗

PubMed1995

A new inherited muscular disorder in Japanese quails (Coturnix coturnix japonica).

Thirteen adult mutant (LWC strain) Japanese quails (Coturnix coturnix japonica), between the ages of 8 and 60 weeks were examined for a progressive muscular disorder. The disorder, inherited as an autosomal dominant trait, was clinically apparent as early as 28 days of age; it was characterized by generalized myotonia, muscle stiffness, and muscle weakness. Affected birds were identified by their inability to lift their wings vertically upward and by their inability to right themselves when placed on their dorsum. Electromyographic studies in two mutant quails showed high-frequency repetitive discharges comparable to those of myotonic runs. These discharges persisted after nerve resection. The distinctive histopathologic changes in the various muscles examined were ring fibers, sarcoplasmic masses, and internal migration of sarcolemmal nuclei. A slight decrease in the size of type IIB muscle fibers and a slight increase in the size of type IIA fibers were observed in the M. pectoralis thoracicus of affected quails. In older affected birds, inter- and intrafascicular fatty infiltration with replacement of type IIB fibers by fat cells was seen in the pectoral muscles. Single fiber necrosis, nonspecific lymphorrages, and variations in the muscle fiber size and shape were also noted. The typical muscle lesions and multisystem involvement, which was manifested by testicular degeneration and atrophy in the male LWC specimens and bilateral lenticular cataracts in 6 of 13 affected mutant quails, suggest resemblance of this new inherited muscular disorder to myotonic dystrophy in man.

Animals↗

PubMed1995

Biliary excretion of furosemide glucuronide in rabbits.

Furosemide (F) was administered to rabbits intravenously and intraduodenaly and the biliary excretion was studied. The major metabolite excreted in bile was furosemide glucuronide (FG). F and acyl migration isomers of FG (FG-iso) were also excreted in bile. The biliary excretion rates of total F (F+FG+FG-iso) following intraduodenal administration of F were much smaller than those following intravenous administration. The fraction of (F+FG-iso) in bile following intraduodenal administration of F were larger than those following intravenous administration. Stability of FG or FG-iso in bile and supernatant solution of the duodenum homogenate of rabbits was studied. FG was unstable in both media and its degradation followed apparent first-order kinetics in both media. In bile, FG degraded to produce several FG-iso and F, while in the supernatant solution of the duodenum homogenate, it hydrolyzed immediately to F. FG-iso were hardly detected in the supernatant solution. These results indicated that FG excreted in bile degraded easily to FG-iso and F. FG might easily hydrolyze to F enzymatically in the duodenum, and the resultant F might be reabsorbed from the intestinal tract. Unabsorbed FG-iso and F might be excreted in the feces.

Adult↗

PubMed1995

Inhibitory effect of ethanol and colchicine on the intracellular processing of beta-glucuronidase which occurs in the Golgi complex.

To investigate the effect of ethanol or colchicine on the intracellular proteolytic processing of lysosomal beta-glucuronidase, which is considered to occur in the Golgi complex in the intracellular sorting pathway, three rat liver Golgi subfractions, GF-1, GF-2, and GF-3, were isolated from ethanol- or colchicine-treated rats, and the electrophoretic patterns of the extracted Golgi beta-glucuronidase on polyacrylamide gel were examined. The isolated Golgi subfractions from the drug-treated rats gave a better yield of fraction than that from the control rats. The enzymatic characterization of these three subfractions showed no significant contamination by other subcellular structures such as plasma membranes, microsomes, or lysosomes, and no inhibitory effect of the drugs was observed. On the other hand, suppressed galactosyltransferase activity, a marker enzyme of the Golgi complex, was detected in the colchicine-treated rats. The electrophoretic pattern of Golgi beta-glucuronidase on polyacrylamide gel revealed one major band which moved to the same position as the lysosomal enzyme type in the control rats. In contrast, in the ethanol- and colchicine-treated rats, Golgi beta-glucuronidase was found to have two major bands stained for enzyme activity resulting from a mixture of microsomal- and lysosomal-type enzymes. These results suggested that the post-translational modification step, during conversion from a microsomal-type enzyme to a lysosomal-type enzyme, was apparently inhibited. Taken together, these findings indicated that ethanol or colchicine administration to rats caused an inhibitory effect on the intracellular post-translational modification of Golgi beta-glucuronidase destined for targeting to the lysosomes.

Animals↗

PubMed1995

Water-soluble antitumor agents. I. Synthesis and biological activity of 6-S-aminoacyloxymethyl mercaptopurine derivatives.

In an attempt to improve the effectiveness and bioavailability of 6-mercaptopurine, various kinds of water-soluble analogues, such as 6-S-aminoacyloxymethyl mercaptopurine derivatives (3a--m) and 6-S,9-disubstituted derivates (7a,b and 9a,b), were synthesized. These compounds were evaluated for activity to augment antitumor immunity by using a double grated tumor system. Antitumor activities against solid tumors (sarcoma 180 and colon 26) were also evaluated. Many compounds exhibited potent activities in both test systems. In particular, the aminopropionate derivative (3a) and the L-glutamate derivative (3f) showed significant enhancement of antitumor immunity together with potent antitumor activities.

Animals↗

PubMed1995

Disinfestation of experimentally infested cat fleas, Ctenocephalides felis, on cats and dogs by oral lufenuron.

In vivo efficacy of orally administered lufenuron, an insect growth regulator, in disinfesting cat fleas was evaluated, using flea-free cats and dogs which were purchased and infested every 10 days with cat fleas from a colony kept in our laboratory. Lufenuron was orally administered as a single dose of 15, 30, or 60 mg/kg to cats, and 5, 10 or 20 mg/kg to dogs. In cats, adult flea emergence was intensively prevented for 30 days by dosing of 15 mg/kg of lufenuron and 40 days by 30 or 60 mg/kg. The average egg hatch rate in 15 mg/kg group was, however, significantly higher than those in 30 mg/kg or more, suggesting necessity to dose 30 mg/kg to cats to prevent development of cat fleas effectively. In dogs, a lower dose of the drug, 10 mg/kg seemed to be sufficient for the complete prevention of flea development.

Administration, Oral↗

PubMed1995

Detection of cytomegalovirus DNA in urine from newborns in NICU using a polymerase chain reaction.

To investigate the natural course of viral shedding during the newborn period, the presence of Cytomegalovirus (CMV) DNA in specimens at 3, 7, 14, 21 and 28 days of life was examined using the polymerase chain reaction (PCR) method. At the 3rd day of life, the viral DNA positive rate in the urine was 7% (4/60), at the 7th day 7% (3/46), at the 14th day 10% (2/20), at the 21st day 10% (1/10), and at the 28th day 25% (1/5). CMV was also detected in samples co-cultivated with HeLa 229 cells and this positive rate was 5% (3/60). The viral positive rate in newborns did not correlate with the gestational age, body weight, or serum IgM level. Six congenital infection cases were identified; two of which were small-for-date babies (SFD) and three of which were born with premature rupture of membranes (PROM). They had no complications during the six months after birth.

Cytomegalovirus↗

PubMed1995

Relationship between the degree of conversion and internal discoloration of light-activated composite.

In order to elucidate the relationship between the degree of conversion and internal discoloration of light-activated composite, four experimental composites which contained different amounts of Bis-GMA and TEGDMA were prepared, and the degree of conversion and discoloration of each composite, with or without annealing, were determined. The degree of conversion was measured by Fourier transformation infrared spectroscopy and the color change was determined after 1, 2, 3 and 4 weeks of immersion in water at 60 degrees C. The non-annealed composites demonstrated a greater degree of conversion and less discoloration as the amount of TEGDMA was increased. Annealed composites showed a significantly greater degree of conversion and less discoloration compared with the non-annealed composites. The results indicate that the greater the degree of conversion, the less the discoloration of composite, and the correlation between the two factors was significant for light-activated composite.

Amines↗

PubMed1995

Report of a case of benign cystic mesothelioma.

A 32-yr-old man was admitted to Anjo Kosei Hospital for the examination of a cystic peritoneal lesion. This patient had a past medical history significant for an appendectomy. Ultrasonography and computed tomography revealed multiple cysts in the abdominal and pelvic cavities. An exploratory laparotomy was performed on July 1, 1993, revealing numerous thin-walled and translucent cysts in the serosal tissues of the parietal and visceral abdominal peritoneum. These cysts were excised surgically because of clinical suspicion of pseudo-myxoma peritonei. Microscopic examination revealed cysts within the thin cyst wall that were composed of fibrous connective tissue and lined by a single layer of cuboidal or flattened epithelium. Immunohistochemical and ultrastructural studies demonstrated that the lining cells were of mesothelial origin, and the diagnosis was benign cystic mesothelioma. In this paper, we present appropriate diagnostic and treatment procedures for benign cystic mesothelioma and discuss the particular usefulness of using immunohistochemical methods to achieve a histological diagnosis.

Adult↗