Search PubMed⌕ Search

Biomedical subjects

K Oda

Publications and source records attributed to K Oda.

At least 577 records · Page 32Linked to original sources
PubMed1984

Induction of rat hepatic alkaline phosphatase and its appearance in serum: electrophoretic characterization of liver-membranous and serum-soluble forms.

Simultaneous bile duct ligation and colchicine injection (2 mg/kg body weight) in rats caused a remarkable induction of alkaline phosphatase in the liver. Concomitantly, a marked elevation of the enzyme activity occurred in the serum, and three activity peaks (peaks I, II, and III) were separated by Sephadex G-200 gel filtration. By several criteria for alkaline phosphatase isoenzymes it was determined that the liver-derived enzyme was distributed in peak I (30% of total serum activity) as a vesicle-bound form and in peak II (65%) as a soluble form, while the intestinal enzyme was contained in peak III (5%). The serum alkaline phosphatase in peaks I and II was compared with the liver enzyme extracted from plasma membrane with n-butanol. Under non-reducing conditions, the soluble form of peak II showed an electrophoretic mobility different from that of the liver enzyme; in the presence of sodium dodecyl sulfate the serum-soluble form migrated a little more slowly than the liver one, while in the presence of Triton X-100 the former migrated much faster than the latter. The sedimentable fraction of peak I was found to contain two forms corresponding to the serum-soluble and liver-membranous forms. Neuraminidase treatment of these two forms reduced their mobilities but did not abolish the relative difference in their mobilities on gel electrophoresis in the presence of either Triton X-100 or sodium dodecyl sulfate. Under reducing conditions, however, each form (which was dissociated into single subunits) migrated with an identical mobility on sodium dodecyl sulfate gel electrophoresis. These results suggest that the hepatic alkaline phosphatase exists as conformationally different forms in the serum and the liver membrane (even solubilized), but the difference is no longer preserved after their denaturation into subunits.

Alkaline Phosphatase↗
PubMed1984

Two types of deletion within integrated viral sequences mediate reversion of simian virus 40-transformed mouse cells.

Simian virus 40 (SV40) DNA insertions from SV40-transformed mouse cell line W-2K-11 and its revertants M18, M31, and M42 were cloned. W-2K-11 cells contain 1.5 copies of the SV40 sequences in a partially tandem duplicated form. The endpoints of the viral sequences at the virus-host junctions are located very close to those reported by others, indicating that there are some preferred sites for integration and rearrangement in SV40 sequences. One flanking cellular sequence is a long stretch of adenine and thymine with repeated AAAT, and the other is a stretch of guanine and cytosine with repeated CCG. There are patchy homologies between the flanking cellular sequences and the corresponding parental SV40 sequences. The sequences around both junctions were retained in all the revertants, whereas most of the internal SV40 sequences coding for large T antigen were deleted. The coding sequences for small T antigen are intact, and small T antigen was expressed in all the revertants. The fragments cloned from M18 and M42 were identical and 3.9 kilobases of SV40 sequences were deleted. The parental SV40 sequences around the deletion site have sequences capable of forming a secondary structure which might reduce the effective distance between the two regions. The SV40 DNA retained in M31 is colinear with SV40 virion DNA, and a unit length of SV40 DNA was deleted within the SV40 sequences present in W-2K-11 cells. These results indicated that two types of deletion occurred during the reversion, one between homologous sequences and the other between nonhomologous sequences.

Animals↗
PubMed1984

Inhibition of in-vitro fertilization of hamster oocytes by a thiol proteinase inhibitor.

Amongst the proteinase inhibitors tested, thiolstatin, a specific inhibitor for the thiol proteinases, leupeptin and antipain, both specific inhibitors of serine- and thiol-proteinases, strongly reduced fertilization of hamster oocytes in vitro. These results suggest the possible involvement of thiol proteinase(s), as well as acrosin, in the fertilization process. A possible role for thiol proteinase in sperm adhesion to the zona pellucida is proposed.

Animals↗
PubMed1984

A polypeptide containing 55 amino acid residues coded by the pre-S region of hepatitis B virus deoxyribonucleic acid bears the receptor for polymerized human as well as chimpanzee albumins.

The receptor for polymerized human and chimpanzee albumins has been identified on a hepatitis B surface antigen polypeptide of approximately 31,000 daltons. The polypeptide, designated P31, is composed of the major polypeptide of hepatitis B surface antigen (P22) and an additional, as yet unidentified, amino acid sequence. We split P31 with cyanogen bromide and obtained a polypeptide of approximately 8000 daltons (P8) that contained carbohydrate. P8 could bind to polymerized human and chimpanzee albumins, but not to polymerized albumins from animals without susceptibility to hepatitis B virus. The amino acid composition of P8 closely resembled that of 55 amino-acid sequence coded by the pre-S region in the deoxyribonucleic acid of hepatitis B virus. Using monoclonal antibody against P8, a solid-phase sandwich radioimmunoassay was developed for the specific determination of hepatitis B surface antigen bearing the receptor for polymerized albumin in the serum of patients with hepatitis B virus infection.

Amino Acid Sequence↗
PubMed1984

Isolation of acetylcholine receptor-like protein from fetal calf thymus.

Cobrotoxin-binding protein from fetal calf thymus was isolated by affinity chromatography after solubilization with Triton X-100 or sodium cholate. Its specificity as a nicotinic acetylcholine receptor (AChR) was determined by assessing the binding to radiolabeled alpha-bungarotoxin (BuTx) and to serum containing antibody against AChR obtained from a patient with myasthenia gravis (MG). AChR-like protein was detected in the amount of 0.41 -2.04 X 10(-9) mol alpha-BuTx binding sites per g protein. Polyacrylamide gel electrophoresis in sodium dedecylsulfate (SDS) revealed polypeptide bands with molecular weights of 40,000, 46,000, 55,000, 70,000, 35,000, and 26,000 daltons. As this protein may play an important role in immunopathological changes in MG, related studies are underway.

Animals↗
PubMed1983

Disparate effects of monensin and colchicine on intracellular processing of secretory proteins in cultured rat hepatocytes.

We have studied the biosynthesis and intracellular processing of three major secretory proteins, albumin, alpha 1-protease inhibitor and alpha 2u-globulin, in cultured rat hepatocytes. The effect of secretion-blocking agents, monensin, a monovalent ionophore, and the microtubule-affecting agents colchicine and taxol was determined. In the control cells, alpha 1-protease inhibitor, a glycoprotein, was first synthesized as an endoglycosidase-H-sensitive form with Mr 51 000, and then processed to two endoglycosidase-H-resistant forms having Mr 51 000 and 56 000, the latter of which was secreted into the medium. Initially synthesized proalbumin was converted with chase to serum-type albumin, while no pro-type precursor was identified for alpha 2u-globulin. In the cells treated with colchicine or taxol, in which secretion was greatly inhibited, the fully processed alpha 1-protease inhibitor and albumin accumulated and were finally secreted into the medium. In the monensin-treated cells, however, most of the newly synthesized alpha 1-protease inhibitor and albumin were not processed to the final mature forms, resulting in accumulation of two 51 000-Mr forms and proalbumin, respectively. Moreover in treated cells, proalbumin and the endoglycosidase-H-resistant alpha 1-protease inhibitor were finally secreted into the medium. Such an effect was not caused by NH4Cl which also inhibited the secretion and is known to exert the similar effect as monensin on the receptor-mediated endocytosis pathway. Based on these results, the use of monensin may prove valuable for more detailed analysis of intracellular processing of various proteins.

Albumins↗
PubMed1983

Antiallergic agents. 2. N-(1H-tetrazol-5-yl)-6-phenyl-2-pyridinecarboxamides.

A new series of N-(1H-tetrazol-5-yl)-6-phenyl-2-pyridinecarboxamides was prepared to determine the effects of substituents on the benzene and pyridine rings on antiallergic activity in the rat passive cutaneous anaphylaxis (PCA) assay after oral administration. One member of this series, N-(1H-tetrazol-5-yl)-4-methyl-6-[4-(methylamino)-phenyl]-2- pyridinecarboxamide (231), has an ED50 value of 0.8 mg/kg po and is 85 times more potent than disodium cromoglycate (DSCG) on intravenous administration. Further evaluation of 231 as a clinically useful antiallergic agent is in progress.

Animals↗
PubMed1983

Equilibrium study on the binding between thermolysin and Streptomyces metalloprotease inhibitor, talopeptin (MKI).

The binding between thermolysin and its specific inhibitor, talopeptin (MKI), was found to show a fluorescence increase when excited at 280 nm and 295 nm, and a difference spectrum characterized by two peaks at 294 nm and 285 nm with a shoulder around 278 nm, indicating a microenvironmental change in tryptophan residue(s) of thermolysin and/or talopeptin. The inhibitor constant of talopeptin against thermolysin, Ki, was determined over the pH range 5-9 from the inhibition of the enzyme activity towards 3-(2-furylacryloyl)-glycyl-L-leucine amide (FAGLA) as a substrate. The dissociation constant of thermolysin-talopeptin complex, Kd, determined directly from fluorometric titration was in good agreement with the inhibitor constant, Ki, between pH 6 and 8.5. The pH dependence of Ki and Kd suggested that at least two ionizable groups of thermolysin in their protonated forms are essential for the binding between thermolysin and talopeptin. The temperature dependence of K1 at pH 5.5 indicated that the binding is largely exothermic (delta H degree = -12 kcal/mol) and essentially enthalpy-driven.

Glycopeptides↗
PubMed1983

Expression of adenovirus type 12 E1A gene in monkey cells, using a simian virus 40 vector.

Simian virus 40 (SV40) recombinants carrying the adenovirus type 12 E1A gene were constructed. The SV40 expression vector was constructed by removing most of the VP1 gene and an internal part of the intervening sequence for late 16S RNA and by joining the 5' and 3' splice sites into a small segment. The adenovirus type 12 E1A gene with or without its own promoter was inserted downstream from the SV40 late promoter and the splicing junctions. The recombinant DNA was propagated and packaged in monkey cells by cotransfection with an early temperature-sensitive mutant (tsA58) DNA as helper. Immunofluorescent staining of the monkey cells infected with the resulting virus stocks showed that up to 20% of the cells overproduced the E1A gene products in the nuclei. Two-dimensional gel electrophoresis of the products indicated that the products were very similar or identical to the authentic polypeptides synthesized in adenovirus type 12-infected human embryo kidney cells. The E1A mRNA was initiated at the SV40 late promoter irrespective of the presence of the E1A promoter and terminated at either the E1A or the SV40 polyadenylation signal. These hybrid mRNAs were correctly spliced in the E1A coding region.

Adenoviruses, Human↗
PubMed1983

Hyperproduction of adenovirus type 12 E1B gene product in monkey cells, using a simian virus 40 vector.

Simian virus 40 recombinant DNAs carrying the adenovirus type 12 E1B gene were constructed, propagated, and packaged in monkey cells. Monkey cells infected with the resulting virus stocks hyperproduced the E1B gene products in more than 80% of the cells as revealed by immunofluorescence. The products were distributed in both the nuclei and the cytoplasm, and a condensed form of fleck structure was observed in the cytoplasm. Polyacrylamide gel electrophoresis of the cell extracts and their immunoprecipitates detected the E1B-coded 19,000-molecular-weight protein but not the 50,000-molecular-weight protein. The 19,000-molecular-weight protein and the simian virus 40 VP1 protein were synthesized in nearly equal amounts.

Adenoviruses, Human↗
PubMed1983

Effect of various proteinase inhibitors on ovulation of explanted hamster ovaries.

Hamster ovaries explanted at 21:00-24:00 h on the day of pro-oestrus were incubated with microbial proteinase inhibitors until 10:30 h on the next morning and the ovulatory blocking effect of these inhibitors was examined. Amongst 11 proteinase inhibitors examined, talopeptin, a specific inhibitor for metallo-proteinases, and alpha-MAPI, a specific inhibitor for serine and thiol proteinases, were the strongest blockers. These 2 inhibitors exhibited a chronological discrepancy in their blocking effect on ovulation. S-SI, plasminostreptin, elastatinal, antipain and chymostatin, which are inhibitors for serine proteinases, partly but significantly inhibited ovulation. The results suggest that, in addition to a metallo-proteinase reported previously, a proteinase which is sensitive to alpha-MAPI is essential for the ovulatory process, and that serine proteinase(s) also participate in ovulation of the hamster ovary.

Animals↗
PubMed1983

Prevalence of autonomic disturbances in diabetics as compared with non-diabetics and healthy subjects.

The prevalence of autonomic disturbances in diabetics was investigated using a direct questionnaire. Compared to non-diabetics and healthy subjects, diabetics had a much higher incidence of paresthesia in the limbs (41%) and impotence (66%). These two symptoms proved to be important in diabetic autonomic neuropathy. Other symptoms of autonomic disturbances in diabetics such as postural vertigo, abnormal sweating, diarrhea and constipation, abnormally cold or burning feet, itching, thirst, urinary bladder disturbance and libido decrease in females seemed to be non-specific for diabetic autonomic neuropathy. Paresthesia in the limbs, abnormally cold or burning feet, urine bladder disturbance and impotence were thought to be related to some degree to the duration, severity and complications of diabetes respectively.

Age Factors↗