Search PubMed⌕ Search

Biomedical subjects

K Okazaki

Publications and source records attributed to K Okazaki.

At least 361 records · Page 20Linked to original sources
PubMed1989

Interspecies crossreactive antigen of the pancreatic duct cell prepared by monoclonal antibody. A preliminary study of its immunological significance in patients with chronic pancreatitis associated with Sjögren's syndrome.

An interspecies cross-reactive antigen (mol wt 60,000) for pancreatic duct cells was prepared by a monoclonal antibody (SP3-1; IgM). Homogenized pig pancreatic tissues were separated by gel filtration chromatography with Sephadex G-100 and ion-exchange column chromatography with DEAE-Sephacel and used as immunogens. Immunohistochemically, antigens against SP3-1 were distributed in duct cells of the pancreas, salivary gland, lacrimal gland, esophageal gland, bile duct, and the distal renal tubule in the pig, monkey, and human. The antigenic determinant contained protein, but not sialic acid or monosaccharide. Preliminary leukocyte migration inhibition test (n = 5) showed positive in four patients with definite Sjögren's syndrome (SS), whereas one patient without autoantibodies similar to SS showed negative. These findings suggest that this antigen may be involved in the pathophysiology in these conditions.

Animals↗
PubMed1989

[Fracture toughness of human enamel].

The fracture toughness (KIC) of human enamel was examined by means of Indentation Microfracture Method (IM method). The IM method was a simple, efficient and economical means to obtain KIC of human enamel. Judging from the relationship between load and crack size, a median crack occurred in the range of 2.45-5.88 N, and KIC was hardly affected by the difference of surface roughness. KIC of a 58-year-old man's teeth was 0.61 MPam1/2 in 1 and 0.77 MPam1/2 in 7 and the difference was significant (P less than 0.01). KIC differed much from the direction of the indenter pressed to enamel rods and the KIC of the direction of enamel rods axis I was markedly higher than that of others. In the 58-year-old man's 1, KIC was 0.61 MPam1/2 in the direction of enamel rods axis V, 0.66 MPam1/2 in the direction of H and 0.84 MPam1/2 in the direction of I, and the difference was significant (P less than 0.01). The values for a 10-year-old man's permanent teeth was slightly higher but showed a similar inclination to the 58-yer-old man's teeth.

Dental Enamel↗
PubMed1989

[A case of mitral regurgitation from non-penetrating chest trauma].

An 18-year-old boy, with no evidence of cardiac murmurs in the past, was admitted to our hospital after steering wheel injury on Nov 22, 1987. He immediately became in shock state. Physical examination revealed a grade 3/6 apical holosystelic murmur and moist rales in lungs. Two-dimensional echocardiography showed a prolapsed anterior leaflet and a lot of pericardial effusion. He recovered soon after subxiphoid pericardiotomy, then we obtained bloody fluid of 200 microliters. In cardiac catheterization study, the pulmonary artery wedge pressure was elevated with a V-wave of 31 mmHg. Coronary angiogram, right ventriculogram, and aortogram were normal, but left ventriculography revealed grade 4 (Seller's) mitral regurgitation. Mitral valve replacement was performed with a Bjork-Shiley prosthesis on Feb 8, 1988. Anterior papillary muscle was in a white necrosis, but not ruptured. Mitral valve leaflets and chordae tendineae were intact. 12 cases of mitral regurgitation from non-penetrating blunt chest trauma were reported in Japan, but we first report a case of mitral regurgitation due to non-ruptured papillary muscle dysfunction.

Adult↗
PubMed1989

In vitro sulfation of sublingual salivary gland mucin: structures of 35S-labeled oligosaccharides.

The enzyme which catalyzes the transfer of sulfate ester group from 3'-phosphoadenosine-5'-phosphosulfate to salivary mucus glycoprotein was located in the detergent extract of the Golgi-rich membrane fraction of rat sublingual salivary glands. Alkaline borohydride reductive cleavage of the synthesized 35S-labeled glycoprotein led to the liberation of the label into the reduced acidic oligosaccharide fraction. A 90.3% of the total label was found incorporated in two oligosaccharides. These were identified in order of abundance as sulfated penta- and heptasaccharides. The pentasaccharide was characterized as SO3H,6G1cNAc beta 1,3Ga1 beta 1, 4G1cNAc beta 1,3(NeuAc alpha 2,6)Ga1NAc-01, and the heptasaccharide as SO3H,6G1cNAc beta 1,3Ga1 beta 1,4G1cNAc beta 1,3Ga1 beta 1,4 G1cNAc beta 1,3(NeuAc alpha 2,6)Ga1NAc-01.

Animals↗
PubMed1989

Synthesis and initial processing of gastric apomucin.

The initiation of the processing of apomucin was investigated using mucus glycoprotein synthesizing polysomes from rat gastric epithelial cells. The polysomes were isolated from cells labeled with [3H]palmitic acid and [14C]N-acetylgalactosamine, purified on Helix pomatia-Sepharose affinity column, dissociated to release peptidyl-tRNA, and chromatographed on DEAE-HPLC column to separate peptidyl-tRNA complexes from the free and ribosomal RNA and proteins. The analysis of the HPLC purified peptidyl-tRNA revealed that complexes were labeled with [3H]palmitic acid and [14C]N-acetylgalactosamine. Digestion of the peptidyl-tRNA with RNase released 3H and 14C labeled peptides, while alkaline degradation destroyed the complex and rendered the [3H]palmitic acid extractable with hexane. The treatment of the 3H and 14C labeled peptidyl-tRNA complexes with alpha-N-acetylgalactosaminidase led to the release of radiolabeled N-acetylgalactosamine, whereas alkaline borohydride reduction produced N-acetylgalactosaminitol. The fatty acid residues have been detected in peptidyl-tRNA containing 2,000Da peptides, whereas N-acetylgalactosamine was discernible on 5,000Da peptides.

Acetylgalactosamine↗
PubMed1988

Aberrant immunoglobulin gene rearrangement in scid mouse bone marrow cells.

We have analyzed Ig gene rearrangement in the immunodeficient mutant mouse, CB-17 scid. Bone marrow stem cells from scid mice were cultured in the in vitro culture system of Whitlock and Witte. Ig gene rearrangement in the scid cells was studied by DNA cloning. Seven DNA clones of Ig H chain JH and DH regions were analyzed by DNA sequencing, and all the clones contained a failure in D-J joining. In the rearranged structure, both DH and JH coding sequences are either partly or completely deleted. Molecular mechanisms causing the aberrant DNA rearrangement are discussed.

Animals↗
PubMed1988

Thymocyte circular DNA excised from T cell receptor alpha-delta gene complex.

We have characterized thymocyte circular DNA excised from the T cell receptor alpha-delta gene complex. Some delta gene clones contained unusual recombinant structures derived from V-(D)-J joining: (i) a reciprocal joint of direct V to J delta joining, skipping the D delta segment; (ii) a V-D delta coding joint lacking an adjacent D delta-J delta coding joint; (iii) a V- D structure containing two D delta segments. Many of the alpha gen clones contained both coding and reciprocal joints of V alpha-to-J alpha joining on the same structure. Most of these coding joints were out of phase; however, in one clone there was an in-phase V-J alpha structure. Interestingly, some alpha gene clones contained the same V gene sequence as rearranged in the delta gene clone, indicating that the same V gene family, at least in part, could be utilized for both the alpha and delta gene systems.

Amino Acid Sequence↗
PubMed1988

Pressure of papillary sphincter zone and pancreatic main duct in patients with alcoholic and idiopathic chronic pancreatitis.

To determine the significance of manometric pressure of the pancreatic duct in patients with alcoholic and idiopathic chronic pancreatitis, we used a microtransducer inserted through a duodenoscope to measure pressures in the papillary sphincter zone and pancreatic main duct in 20 control subjects and 31 patients with chronic pancreatitis without papillary stenosis including 10 cases of alcoholic chronic pancreatitis (ALCP) and 21 cases of idiopathic chronic pancreatitis (ICP). The pancreatic main ductal pressure was significantly higher in the patients with ALCP (55.7 +/- 28.9 mm Hg) or ICP (44.5 +/- 25.8 mm Hg) than in the controls (16.2 +/- 8.7 mm Hg), but there was no significant difference between ALCP and ICP. There was no significant difference between control subjects and ICP in the motility of the sphincter of Oddi. In ICP there were no correlationships between pancreatic ductal pressure and the motility of papillary sphincter zone. In ALCP, the frequency of the papillary sphincter waves was significantly higher than in normal subjects and there was a correlation between the pancreatic ductal pressure and the motility of the papillary sphincter zone. These data suggest that increased pancreatic ductal pressure in ALCP may be in part due to papillary dysfunction, but not in ICP.

Alcoholism↗
PubMed1988

Pressure of papillary sphincter zone and pancreatic main duct in patients with chronic pancreatitis in the early stage.

We measured pressures of the papillary sphincter zone and pancreatic main duct endoscopically in 20 control subjects and in 38 patients with chronic pancreatitis without papillary stenosis, including 19 cases believed to be in the early stages of chronic pancreatitis. There was no significant difference between control subjects and patients with chronic pancreatitis without papillary stenosis in the motility of the sphincter of Oddi. The pancreatic main ductal pressure was significantly higher in the patients in the early stage of chronic pancreatitis (35.7 +/- 9.1 mm Hg (mean +/- SD) in patients suspected of having chronic pancreatitis and 44.9 +/- 20.4 mm Hg in minimal-change chronic pancreatitis) than in the controls (16.2 +/- 8.7 mm Hg). The viscosity of pure pancreatic juice of patients with chronic pancreatitis (5.0 centi-Poise (cP] in the basal secretory phase was significantly higher than that of the controls (1.32 cP). These data suggest that endoscopic measurement of pancreatic ductal pressure is useful for diagnosis of the early stages of chronic pancreatitis.

Adult↗
PubMed1988

Gastric mucin hydrophobicity: effects of associated and covalently bound lipids, proteolysis, and reduction.

The hydrophobic properties of gastric mucus glycoprotein were investigated using the fluorescent probe, bis(8-anilino-1-naphthalenesulfonate). The glycoprotein was subjected to removal of associated and covalently bound lipids, peptic degradation, and disulfide bridge reduction. Fluorescence titration data revealed the presence of 55 hydrophobic binding sites in the intact mucin molecule, 71 binding sites in the glycoprotein devoid of associated lipids, and 53 binding sites in the glycoprotein devoid of associated lipids and covalently bound fatty acids. Proteolytic digestion of the glycoprotein with pepsin essentially abolished the probe binding, while reduction of disulfide bridges resulted in glycoprotein subunits whose combined number of binding sites was about 3 times greater than that of the mucin polymer. The binding of the probe to mucus glycoprotein varied with the pH of the medium, being highest at pH 2.0 and lowest at pH 9.0. The results indicate that lipids contribute to the hydrophobic character of gastric mucin and that hydrophobic binding sites reside on the nonglycosylated regions of the glycoprotein polymer buried within its core.

Animals↗
PubMed1988

Motility of the sphincter of Oddi and pancreatic main ductal pressure in patients with alcoholic, gallstone-associated, and idiopathic chronic pancreatitis.

We endoscopically measured pressures of the pancreatic duct (PP) and the sphincter of Oddi (SO) in patients with alcoholic (ALCP, n = 10), gallstone-associated (GSCP, n = 7), and idiopathic chronic pancreatitis (ICP, n = 21), and in 20 controls. The PP was significantly higher in the patients with ALCP (55.7 +/- 28.9 mm Hg), GSCP (33.6 +/- 16.2 mm Hg), or ICP (44.5 +/- 25.8 mm Hg) than in the controls (16.2 +/- 8.7 mm Hg), but there was no significant difference between ALCP, GSCP, and ICP. There was no significant difference between control subjects and ICP in the motility of SO. In ICP, there was no correlation between the PP and the motility of SO. In ALCP and GSCP, the frequencies of the papillary sphincter waves were significantly higher than in normal subjects, and there were correlations between the PP and the motility of SO. These data suggest that increased pancreatic ductal pressure in GSCP with papillitis or ALCP may be due in part to papillary dysfunction, but not in ICP.

Alcoholism↗
PubMed1987

Catalase gene of the yeast Candida tropicalis. Sequence analysis and comparison with peroxisomal and cytosolic catalases from other sources.

A clone harbouring the genomic DNA sequence for the peroxisomal catalase of an n-alkane-utilizable yeast, Candida tropicalis, has been isolated by the hybrid-selection method and confirmed with a probe of catalase partial cDNA. Nucleotide sequence analysis of the cloned DNA disclosed that the gene fragment coding for catalase had a length of 1455 base pairs (corresponding to 485 amino acids; m = 54937 Da), and that the size of this enzyme was the smallest among all catalases reported hitherto. No intervening sequence was found in this coding region and some portions coincided with the amino acid sequences obtained from the analysis of the purified catalase. The comparison with three peroxisomal catalases from rat liver, bovine liver and human kidney, and one cytosolic catalase from Saccharomyces cerevisiae has revealed that catalase from C. tropicalis was more homologous to the peroxisomal enzymes than to the cytosolic one. C. tropicalis used the codons of the high-expression type. Amino acid residues were all conserved at the active and heme-binding sites. In the N and C-terminal regions there was no characteristic signal sequence or consensus sequence. However, a noticeable region, which can be discriminated between peroxisomal and cytosolic catalases, was proposed.

Amino Acid Sequence↗
PubMed1987

A pre-B cell nuclear protein that specifically interacts with the immunoglobulin V-J recombination sequences.

DNA-nuclear protein interactions were studied with synthetic recombination signal sequences (RSSs) for immunoglobulin V-J joining. With a gel retardation assay, a DNA-binding protein that specifically interacts with RSSs was detected in nuclear extracts from a pre-B cell line, 38B9. This protein was found in all the recombination-competent pre-B cell lines tested in this study, but not in myeloma, mature T cell, monocyte, or fibroblast cell lines. DNA footprint analysis with dimethyl sulfate demonstrated that the 7-mer region of the RSS was strongly protected when complexed with the binding protein. Furthermore, a single base substitution in the 7-mer region totally abolished the binding. The molecular mechanism of V-J joining is discussed in the context of the RSS-binding protein.

Animals↗
PubMed1987

Two pairs of recombination signals are sufficient to cause immunoglobulin V-(D)-J joining.

The minimum sequence requirements for antigen receptor V-(D)-J joining were studied by constructing recombination-substrates containing synthetic recombination signals and introducing them into a recombination-competent pre-B cell line. Two sets of heptamer (CACTGTG) and nonamer (GGTTTTTGT) sequences were shown to be sufficient to cause the V-(D)-J joining, if the 12- and 23-base pair spacer rule is satisfied. A point mutation in the heptamer sequence, or a change in the combination of the two spacer lengths, drastically reduced the recombination.

Animals↗
PubMed1987

T cell receptor beta gene sequences in the circular DNA of thymocyte nuclei: direct evidence for intramolecular DNA deletion in V-D-J joining.

We have identified circular DNA containing T cell receptor (TCR) beta gene sequences in mouse thymocytes, thereby providing direct evidence for the intramolecular DNA deletion model of V-D-J joining in TCR beta genes. Two types of excision products of V-D-J joining have been identified. Type I, a circular reciprocal recombinant of normal V-D or D-J joining, contains a 7mer-7mer head-to-head structure expected from an excised product of normal V-D or D-J joining. Type II contains a D beta 2-J beta 1 structure on the circular DNA; the recombination event producing this molecule occurs between an upstream J and a downstream D segment, probably leaving the reciprocal 7mer-7mer structure on the chromosome. Some type I molecules seem to represent excision products of secondary joining after formation of the first D-J or V-D-J structure. The recombination mechanism that generates the circular DNA is discussed.

Amino Acid Sequence↗
PubMed1987

Potentiation of cytotoxicity of 1-beta-D-arabinofuranosylcytosine for K562 human leukemic cells by cadeguomycin.

The treatment of K562 human myeloblastic leukemia cells and YAC-1 murine lymphoma cells with cadeguomycin at concentrations over 0.6 microM significantly enhanced the cytotoxicity of 1-beta-D-arabinofuranosylcytosine (ara-C). The degree of potentiation depended upon the antibiotic concentration. The treatment with 75 microM cadeguomycin for 18 h increased cellular uptake of [3H]ara-C into K562 cells and formation of ara-C nucleotides, as well as incorporation into nucleic acids. The level of the diphosphate of ara-C plus the triphosphate of ara-C was approximately 10 times higher in the cadeguomycin-treated cells than in the untreated cells by 30 min of incubation with [3H]ara-C. The extracts of 15 microM cadeguomycin-treated K562 cells showed increased activity of formation of ara-C nucleotides, resulting in 4- to 5-fold higher formation of the di- and triphosphates of ara-C than the control cell extracts. Cadeguomycin did not significantly change the level of ribonucleotide and deoxyribonucleotide pool in K562 cells. The mechanism of potentiation of ara-C by cadeguomycin was discussed.

Anti-Bacterial Agents↗
PubMed1987

Intracellular localization and transport of three different bovine herpesvirus type 1 glycoproteins involved in neutralization.

Monoclonal antibodies against 3 different glycoproteins of bovine herpesvirus type 1 (BHV-1) involved in virus neutralization were used in indirect immunofluorescence (IIF) tests to characterize the appearance and transport to the plasma membrane of virus antigens in the infected cells. Antibodies against gp 117 and gp 71 glycoproteins first showed pronounced ring-like nuclear fluorescence at 4 hours post-infection (PI), followed by staining of the perinuclear region, presumably the Golgi apparatus. In contrast, antibody against gp 87 produced staining in cell-to-cell junctional areas at 3 hours PI before any staining close to the nucleus. The expression of the 3 glycoproteins at the surface of the infected cells was confirmed by the use of monoclonal antibodies having neutralizing activity, but not by non-neutralizing antibodies against gp 117 and gp 71. Non-neutralizing antibody against gp 87 detected the surface fluorescence only in those cells showing marked degeneration. Inhibition of glycosylation of the viral glycoproteins with tunicamycin (TM) was followed by interference with transport of gp 117 and gp 87 to the plasma membrane. On the other hand, gp 71 was incorporated into the plasma membrane despite the lack of N-linked glycosylation.

Animals↗