Biomedical subjects

K Okazaki

Publications and source records attributed to K Okazaki.

At least 271 records · Page 15Linked to original sources

PubMed1993

Presence and possible involvement of Ca/calmodulin-dependent protein kinases in insulin release from the rat pancreatic beta cell.

Roles of Ca/calmodulin-dependent protein kinase II (Ca/CaM kinase II) and myosin light chain kinase (MLCK) in insulin release from rat pancreatic islets were investigated. Western blotting using polyclonal antibody to Ca/CaM kinase II suggested the presence of this kinase in the pancreatic islets. Extracts of pancreatic islets phosphorylated exogenous myosin light chain, which was inhibited by ML-9, an inhibitor of MLCK. KN-62 and KN-93, inhibitors of Ca/CaM kinase II, and ML-9 at microM concentrations inhibited insulin release stimulated by glucose or high K+. KN-62 and KN-93, but not ML-9, inhibited insulin release increased by glucose and forskolin, an activator of adenylate cyclase. These inhibitors had no effect on insulin release evoked by 12-O-tetradecanoyl phorbol-13-acetate, an activator of Ca(2+)-sensitive, diacylglycerol-dependent protein kinase. These results suggest that Ca/CaM kinase II and MLCK may participate in the control of insulin release.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1993

Degradation of Mos by the N-terminal proline (Pro2)-dependent ubiquitin pathway on fertilization of Xenopus eggs: possible significance of natural selection for Pro2 in Mos.

The c-mos proto-oncogene product (Mos), an essential component of the cytostatic factor responsible for meiotic arrest in vertebrate eggs, undergoes specific proteolysis soon after fertilization or activation of Xenopus eggs. To determine the degradation pathway of Mos on egg activation, various Mos mutants were expressed in Xenopus eggs and their degradation on egg activation was examined. Mos degradation absolutely required its penultimate proline (Pro2) residue and dephosphorylation of the adjacent serine (Ser3) residue. These degradation signals were essentially the same as those of Mos in meiosis I of Xenopus oocyte maturation, where Mos has been shown to be degraded by the 'second-codon rule'-based ubiquitin pathway. To test whether Mos degradation on egg activation is also mediated by the ubiquitin pathway, we attempted to identify and abrogate a specific ubiquitination site(s) in Mos. We show that the major ubiquitination site in Mos is a Lys34 residue and that replacement of this residue with a non-ubiquitinatable Arg residue markedly enhances the stability of Mos on egg activation. These results indicate that the degradation of Mos on egg activation or fertilization is mediated primarily by the N-terminal Pro2-dependent ubiquitin pathway, as in meiosis I of oocyte maturation. The N-terminal Pro2 residue of Mos appears to be naturally selected primarily for its degradation on fertilization, rather than that in meiosis I.

Amino Acid Sequence↗

PubMed1993

Cancerous residue in breast-conserving surgery.

Local tumor extension was studied using a continuous series of multiple blocks of mastectomy specimens to assess malignancy remaining after breast-conserving surgery for early-stage breast cancer. In this study, 183 cases were chosen, consisting of 6 noninvasive ductal carcinoma cases and 177 invasive ductal carcinoma cases. The histopathology in 59 (32%) of the 183 cases corresponded to that showing extensions of more than 2.6 cm from the tumor margin. These wide extensions were also seen in 17% of breast cancers with a tumor size of less than 2 cm. The incidence of wide extension was higher in younger patients with cases of noninvasive ductal carcinoma. Extension to the nipple-areola was seen in 14% of cases with a tumor size of less than 2 cm. Breast cancers with multicentric development accounted for 3% of those with a tumor size under 2 cm. These findings suggest that if lumpectomy is performed with a margin of 2 cm for tumors with a size of 2 cm or less, a cancerous residue would be found in the surgical margin of 15-20% of the cases. The actual incidence was 23% of cases after breast-conserving treatment in our study. On the basis of the data, breast-conserving treatment with only local resection of the primary lesion showed cancerous residue such as intraductal cancerous extension in about 20% of cases. Therefore, it was concluded that, as part of breast-conserving therapy of early-stage breast cancer, radiation therapy of the whole breast should be performed after surgery with clear margins to control local recurrence.

Adult↗

PubMed1993

Hemadsorptive activity of transfected COS-7 cells expressing BHV-1 glycoprotein gIII.

Bovine herpesvirus 1 (BHV-1) glycoprotein gIII plays an important role in virus adsorption. The SR alpha promoter expression vector containing BHV-1 gIII gene was transfected into COS-7 cells. Fluorescent antibody staining using a panel of monoclonal antibodies demonstrated antigenic authenticity with regard to at least three nonoverlapping neutralization sites as well as surface expression of the glycoprotein. C57BL mouse erythrocytes were found to absorb onto the gIII-expressing cells. The hemadsorbing activity was specifically inhibited by the monoclonal antibody blocking virus adsorption. Heparin, analog of cellular receptor for BHV-1, also prevented the erythrocytes from adsorbing to the cells and heparinase-treated erythrocytes showed no adsorption. These findings indicate that the gIII binds to the erythrocytes and probably to the host cells independently of other viral components.

Animals↗

PubMed1993

Specific cellular immune responses to pancreatic antigen in chronic pancreatitis and Sjögren's syndrome.

The specific cellular immune response to the partially purified pancreatic antigen was studied by the peripheral blood lymphocyte proliferation assay in patients with chronic pancreatitis, Sjögren's syndrome, and primary biliary cirrhosis. A significant positive result (stimulation index > 2.0) was observed in 7 of 21 patients with idiopathic chronic pancreatitis (33%; P < 0.05), 6 of 7 patients with Sjögren's syndrome-associated chronic pancreatitis (86%; P < 0.0005), and 6 of 11 patients with Sjögren's syndrome (55%; P < 0.01), compared to normal controls whose stimulation index was 0.94 +/- 0.28 (mean +/- SD; n = 14; range, 0.56-1.60). On the other hand, patients with alcoholic chronic pancreatitis (17%; n = 12), stone-related chronic pancreatitis (0%; n = 7), primary biliary cirrhosis-associated chronic pancreatitis (33%; n = 3), primary biliary cirrhosis (0%; n = 4), systemic lupus erythematosus (17%; n = 6), and autoimmune thyroiditis (0%; n = 6) showed no significant difference from normal controls. Furthermore, in patients with idiopathic chronic pancreatitis who had positive results, a lymphocyte proliferative response to the pancreatic antigen was observed in T cells, especially in the CD4+ T cell subpopulation. These results suggest that the pancreatic antigen plays a role in the pathogenesis of a part of idiopathic chronic pancreatitis and Sjögren's syndrome in association with T cell responses and, also, suggest that autoimmunity may be a possible etiological factor in chronic pancreatitis.

Animals↗

PubMed1993

In vitro transcription and replication of the mumps virus genome.

By the use of lysolecithin-permealized extracts from mumps virus-infected HeLa cells, we have developed an in vitro system, which not only directed the synthesis of mumps virus mRNAs but also supported replication of the genomic RNA. Furthermore, upon transcription of the P gene, both faithful and edited copies of the P gene were detected by RNase mapping with a riboprobe. Thus this system seems to promote biochemical analyses of underlying mechanisms operative in mumps virus gene expression and replication, including RNA editing.

Cell-Free System↗

PubMed1993

Major histocompatibility antigen-restricted cytotoxicity in inflammatory bowel disease.

BACKGROUND: The role of cytotoxicity mediated by peripheral blood mononuclear cells for colonic epithelial cells in inflammatory bowel disease (IBD) is still controversial. To clarify it, we studied major histocompatibility antigen (MHC)-restricted T cell-mediated cytotoxicity (CTL). METHODS: Cytotoxicity was measured by 51Cr release from colonic cells after the 6-hour incubation with peripheral blood mononuclear cells in 11 IBD patients (6 with Crohn's disease and 5 with ulcerative colitis). RESULTS: CTL activity (E/T ratio = 200:1 or 100:1) for autologous target cells was significantly increased (22%-40%) in 5 of 6 CD and 4 of 5 UC patients (22%-64%) compared with that for allogeneic target cells. The increase in CTL activity was mainly inhibited by anti-MHC class I and CD8 monoclonal antibodies (50 micrograms/mL), while it was partially inhibited by anti-MHC class II or CD4 antibodies in some patients. Complement-mediated depletion of CD2+ cells also significantly decreased CTL activity. CONCLUSIONS: The results indicate that MHC-restricted T cell cytotoxicity may play a role in mucosal damage in some patients of IBD.

Adolescent↗

PubMed1993

Neurocalcin family: a novel calcium-binding protein abundant in bovine central nervous system.

We purified and sequenced from bovine brain a novel calcium-binding protein. This protein which we named neurocalcin has 3 putative EF hand motifs and a close homology with recoverin which activates guanylate cyclase Ca2+ dependently. Neurocalcin has at least 6 isoforms and is expressed in the central nervous system (CNS), retina and adrenal gland. Considering unique distribution of neurocalcin, this protein may an important physiological role which differs from that of visinin or recoverin.

Amino Acid Sequence↗

PubMed1993

Differentiation of mumps vaccine strains from wild viruses by single-strand conformation polymorphism of the P gene.

The DNA fragments amplified through the polymerase chain reaction from part of the P gene of four mumps vaccine strains (Urabe, Torii, Hoshino and Miyahara) were subjected to single-strand conformation polymorphism (SSCP) analysis. These four vaccine strains were differentiated from each other. Furthermore, twelve wild viruses and a laboratory strain (Enders strain) were also distinguished by this method. Viruses isolated from patients who developed aseptic meningitis 4 to 6 weeks after measles-mumps-rubella vaccination showed identical SSCP patterns with the vaccine strain used for immunization. These results were well correlated with sequence analysis of P-gene segments, indicating high applicability of the SSCP analysis for differentiation of mumps vaccine strains not only from each other but from wild viruses.

DNA, Single-Stranded↗

PubMed1993

Mechanical properties of a Ti-6A1-4V dental implant produced by electro-discharge compaction.

Cylindrical, porous-surfaced implants were fabricated from Ti-6A1-4V atomized powders by an electro-discharge compaction technique (EDC). Input energy (1-2.5 kJ/g powder) was used to produce implant compacts having a solid core surrounded by a porous layer. The solid core size, neck size between core and particle, neck size between particles, and pore size in the porous layer varied as input energy was changed. Compression tests were carried out to evaluate the mechanical properties of the EDC compacts. The yield strength ranged from 270 to 530 MPa and the ultimate compressive strengths ranged from 390 to 600 MPa. The yield strengths for solid core, core-particle and particle-particle interfaces remained constant at 755 MPa regardless of input energy. The endurance limits estimated from these results were 190-310 MPa, which were higher than the reported values for sintered titanium implants. Microhardness testing revealed that hardness was independent of input energy and the position where the testing indentation was applied. The average hardness of the compacts was 3430 MPa.

Aluminum↗

PubMed1993

Speech and velopharyngeal function following maxillary advancement in patients with cleft lip and palate.

The influence of maxillary advancement by osteotomy on speech was examined in 10 patients with cleft palates (6 males, 4 females). Ages at the time of surgery ranged from 16 to 26 years (mean, 19.5 yr). LeFort I and II osteotomies were performed in 9 patients and 1 patient, respectively. Preoperatively and postoperatively, hypernasality, nasal emission on pressure consonants, and articulation disturbances were evaluated perceptually, and velopharyngeal function was evaluated by lateral cephalographic and nasopharyngoscopic studies. Hypernasality, which had been judged preoperatively to be absent or slight in 1 patient each, remained unchanged after surgery, whereas the remaining 8 patients showed increased hypernasality after surgery. Nasal emission showed a similar tendency. Articulation errors were not improved postoperatively. Lateral cephalograms recorded from the patients with increased hypernasality showed increases in the shortest palatopharyngeal length and in the soft-palate-length--to--pharyngeal-depth ratio. Also, deterioration in velopharyngeal closure was noted postoperatively compared with preoperatively by nasopharyngoscopy in the majority of patients with increased hypernasality.

Adolescent↗

PubMed1993

Effects of adenosine triphosphate (ATP) on somatosensory evoked potentials in humans anesthetized with isoflurane and nitrous oxide.

In order to examine the usefulness of adenosine triphosphate (ATP) as an adjuvant to anesthesia for surgery requiring intraoperative somatosensory evoked potential (SSEP) monitoring, we have studied the effects of ATP on SSEPs in patients anesthetized with isoflurane and nitrous oxide (N2O). A control recording of SSEP was performed while anesthesia was maintained with 0.5% end-tidal concentration of isoflurane in 60% N2O. The recordings were repeated after an ATP infusion had been added to this basal anesthesia at the rates of 100 micrograms.kg bw-1.min-1 and 200 micrograms.kg bw-1.min-1. SSEP was also studied when end-tidal isoflurane concentration was increased to 1.5% after cessation of ATP infusion. An infusion of ATP combined with 0.5% isoflurane and 60% N2O effectively inhibited an increase in blood pressure during surgery. The amplitude of the cortical component of SSEP was lowered by 1.5% isoflurane, which also increased both cortical and spinal latencies as well as central conduction time (CCT). In contrast ATP infusions at both rates induced no significant changes in latencies, amplitude and CCT. The results indicate that ATP infusion combined with 0.5% isoflurane in 60% N2O can be a useful anesthetic technique for intraoperative SSEP monitoring because adequate anesthetic depth can be maintained by a low concentration of anesthetics without further suppression of SSEPs.

Adenosine Triphosphate↗

PubMed1993

Adhesion of Helicobacter pylori to gastric epithelial cells in primary cultures obtained from stomachs of various animals.

Of 35 strains of Helicobacter pylori tested, 5 were found to adhere well to HEp-2 cells. We selected three of these adhesive strains and four from the remaining strains to examine their ability to adhere to gastric epithelial cells in primary cultures obtained by collagenase digestion of stomachs from mice, rats, Mongolian gerbils, guinea pigs, pigs, and cynomolgus monkeys. The three adhesive strains adhered well to epithelial cells from monkey and pig gastric antra. The adhesion was inhibited by incubating the bacterial cells with fetuin, and this inhibition was further confirmed by the binding of gold-labeled fetuin to the surface of the adhesive strains. However, these adhesive strains only weakly adhered to fundic epithelial cells from monkeys and pigs and to gastric epithelial cells from the other animals. As for the four strains poorly adhesive to HEp-2 cells, they adhered weakly to gastric epithelial cells from all of the animals tested. They had higher hemagglutination titers than the adhesive strains, showing that there was no correlation between hemagglutination titers and the ability to adhere to gastric cells. Taking the similarities of human and monkey or pig stomachs into consideration, these results suggest that the primary target cell of H. pylori in colonization in human stomachs is the antral epithelial cell and that the putative adhesin involved in adhesion has affinity for fetuin.

Animals↗

PubMed1993

Identification of an amino acid that defines the fusogenicity of mumps virus.

Recombinant cDNA clones representing the fusion (F) and hemagglutinin-neuraminidase (HN) proteins of two mumps virus strains different in fusogenicity were constructed. Upon transfection of COS7 cells, extensive cell fusion was observed only when cells expressed the F protein of the fusing strain together with the HN protein derived from either strain. Mutational analyses further showed that the amino acid at position 195 of the F protein plays a critical role in determining the extent of cell fusion induced by mumps virus, since replacement of Ser-195 by Tyr significantly reduced the fusion inducibility of otherwise fusion-competent F protein.

Animals↗

PubMed1993

Effect of short-term administration of dexamethasone on canine antral gastrin gene expression.

The acute effect of corticosteroids on the release and biosynthesis of gastrin still remains unclear. We report the effect of short-term administration of dexamethasone on the antral gastrin gene expression and gastrin levels in 6 dogs, which were treated with dexamethasone (1.5 mg/kg, i.m. daily) for 3 days. One day after treatment, gastrin mRNA levels increased (152 +/- 14%), but serum and tissue gastrin showed no significant changes. With 2 and 3 days of dexamethasone treatment, gastrin mRNA (2 days: 163 +/- 28%, 3 days: 170 +/- 22%), serum gastrin (2 days: from 94 +/- 12 to 168 +/- 23 pg/ml, 3 days: to 180 +/- 16 pg/ml) and tissue gastrin concentration (2 days: from 480 +/- 32 to 664 +/- 31 pg/mg tissue protein, 3 days: to 708 +/- 45 pg/mg tissue protein) significantly increased. However, gastrin mRNA levels were not increased even after 1 day culture of canine antral tissue with dexamethasone in vitro. These findings suggest that short-term administration of corticosteroid may increase the canine gastrin gene expression in vivo by an unknown pathway.

Animals↗

PubMed1993

Inhibition of appearance of pH-dependent virus-cell fusion by neutralizing monoclonal antibodies to transmissible gastroenteritis virus.

Five MAbs, which showed neutralizing (NT) activity and recognized S (previously designated E2) glycoprotein of TGE virus TO-163, inhibited cell fusion by TGE virus in IB-RS-2 cells. Other S-specific MAbs with no NT activity did not inhibit the cell fusion. The results indicate that a neutralization epitope is same or very close to a fusion active site. The kinetics of membrane fusion following a reduction in pH were also investigated. The cell fusion appeared between 2 and 6 hr after the binding medium was added.

Animals↗

PubMed1993

Diversity of the virulence for C57BL mice among BHV-1 strains.

Virulence of bovid herpesvirus 1 (BHV-1) for C57BL suckling mice was compared among respiratory, genital and attenuated vaccine strains. The 50% mouse lethal dose of the respiratory strain was approximately 1,000-fold lower than that of the vaccine strain. The genital strain showed intermediate virulence. The kinetic studies suggested that the respiratory strain appeared to multiply in the brain of the animals, and that the genital and vaccine strains were eradicated from the animals.

Animals↗

PubMed1993

Distinct regional localization of neurocalcin, a Ca(2+)-binding protein, in the bovine adrenal gland.

Neurocalcin (molecular weight 23,000 and 24,000) is a Ca(2+)-binding protein with three putative Ca(2+)-binding domains and is present in large amounts in nervous tissues. Neurocalcin isoproteins separated by C18 reverse-phase column chromatography are insoluble in buffer solution and it is impossible to determine the dissociation constant of neurocalcin with Ca2+. To overcome this difficulty, recombinant neurocalcin was synthesized, based on one of the cDNAs of the neurocalcin isoproteins. Stoichiometric titration experiments, using recombinant neurocalcin, indicated that this protein bound 2 mol Ca2+/mol protein and that the apparent dissociation constant for Ca2+ was 2.2 mumol/l, suggesting that neurocalcin plays a physiological role in cellular function. Immunoblotting showed that neurocalcin is present in the bovine adrenal gland in addition to the nervous tissues. Neurocalcin, identified by immunoblotting, was purified from the bovine adrenal gland. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of neurocalcin from the bovine brain showed 23 kDa and 24 kDa double bands, while SDS-PAGE of neurocalcin from the adrenal gland showed a single band of apparently 24 kDa, suggesting that the expression of neurocalcin isoproteins differs from tissue to tissue. The content of neurocalcin in the adrenal gland was 10 micrograms protein/100 g wet tissue. Immunohistochemical analysis showed the occurrence of neurocalcin in zona glomerulosa and adrenal medulla but not in zona fasciculata or zona reticularis. The restricted localization of neurocalcin in the adrenal gland suggests that a similar Ca2+signal pathway may be present in zona glomerulosa a nd the adrenal medulla.

Adrenal Glands↗