Biomedical subjects

Y Abiko

Publications and source records attributed to Y Abiko.

At least 199 records · Page 11Linked to original sources

PubMed1989

Release of adenosine and lactate from human hearts during atrial pacing in patients with ischemic heart disease.

Thirty-eight patients treated by atrial pacing were divided into three groups (Group I, patients with neither coronary stenosis nor anginal pain during pacing; Group II, patients with no coronary stenosis but having anginal pain during pacing; Group III, patients with coronary stenosis). The concentrations of adenosine and lactate were measured in the coronary sinus blood and in the arterial blood before, during, and after atrial pacing. During atrial pacing, significant levels of adenosine were released from the heart of patients in Group III, whereas significant lactate release was observed in Groups II and III. In Group II, the concentration of adenosine in coronary sinus blood appeared to increase during pacing, but not significantly. There was no significant correlation between the release of adenosine and that of lactate. A significant release of adenosine due to atrial pacing may be observed only in patients with coronary artery disease.

Adenosine↗

PubMed1989

A possible involvement of oxygen free radicals in the development of myocardial acidosis during coronary occlusion in dogs.

The present study was designed to examine whether free radical scavengers attenuate myocardial acidosis induced by partial occlusion of the coronary artery in dogs. The myocardial pH was determined by a micro glass pH electrode inserted in the endocardial layers of the left ventricular wall perfused by the left anterior descending coronary artery. The left anterior descending coronary artery was occluded for 90 min incompletely so that the flow would be 1/2-1/3 the original flow. The myocardial pH before partial occlusion was 7.54-7.55. Partial occlusion decreased the flow in the left anterior descending coronary artery by 49.3-64.9% and the myocardial pH by 0.71-0.76, and increased the ST segment (surface electrocardiogram) by 6.3-9.3 mV. Saline (0.5 ml/kg), recombinant human superoxide dismutase (70,000 or 210,000 U/kg), or catalase (55,000 or 165,000 U/kg) was injected intravenously 30 min after partial occlusion. The injection of recombinant human superoxide dismutase or catalase alone did not restore the myocardial pH that had been decreased by coronary occlusion. The combined injection of recombinant human superoxide dismutase (70,000 U/kg) + catalase (55,000 U/kg), however, restored the myocardial pH without restoration of ST segment. In conclusion, recombinant human superoxide dismutase + catalase attenuated myocardial acidosis during ischaemia, suggesting a possible involvement of oxygen free radicals in the development of myocardial acidosis (especially in the endocardial layers) during ischaemia.

Acidosis↗

PubMed1989

Cloning of the gene for cell-surface protein antigen A from Streptococcus sobrinus (serotype d).

A gene library of Strep. sobrinus B13N (serotype d) chromosomal DNA was constructed in Escherichia coli, with the bacteriophage vector lambda L47.1. A recombinant phage, lambda MDSM49, containing a 15.5 kb DNA insert, directed the expression of a 210 kDa antigenic protein. The recombinant 210 kDa protein was shown by Western blot analysis to be identical with cell-surface protein antigen A (spaA) from a serotype g strain. However, the restriction patterns of a subclone plasmid, pMD51, from lambda MDSM49 differed from those of serotype g strain. The cell-surface protein antigen I/II from serotype c Streptococcus mutans is a potential immunogen for vaccination against dental caries and corresponds to the spaA from serotype d and g strains. A recombinant clone, pDM51, will be a useful tool for serological and molecular biological studies. The recombinant spaA provides useful material for assessment of its diagnostic and immunogenic potential.

Antigens, Bacterial↗

PubMed1989

Genetic characterization of the spaA1 determinant of the surface protein antigen gene from Streptococcus sobrinus 6715.

1. The surface protein antigen-encoding gene spaA1, previously cloned from Streptococcus sobrinus 6715 (serotype g) into the plasmid pACYC184, was examined. 2. The gene product of pYA726 was identified both by the minicell method and by in vitro transcription-translation system as a protein whose mol. wt was estimated to be 140,000. 3. The spaA1 gene was localized on the 3.75 kb AvaI-BamHI fragment of the cloned DNA. 4. An internal spaA1 promoter located close to one end of the 1.25 kb AvaI fragment within the 3.75 kb AvaI-BamHI fragment initiated the transcription for the insert DNA of S. sobrinus autonomously.

Bacterial Proteins↗

PubMed1989

Free arachidonic acid source for PGE2 and TXB2 production in guinea pig peritoneal macrophages exposed to insoluble glucan from Streptococcus mutans.

1. Macrophages are an important source of the lipid mediators arachidonic acid (AA) and its metabolites that are produced during inflammation. 2. Previously, we reported that insoluble glucans from Streptococcus mutans in dental plaque could induce macrophages to secrete PGE2 and TXB2. 3. Studies were undertaken to identify the phospholipid substrates that can serve as a source of AA in macrophages exposed to the insoluble glucan. 4. When macrophage cell prelabelled with [3H]AA, stimulation with insoluble glucan resulted in a loss of label mainly from phosphatidylcholine (PC) and phosphatidylinositol (PI). 5. In addition, the PC-, and PI-specific phospholipase A2-mediated mechanisms for AA release may be activated in guinea peritoneal macrophages exposed to the insoluble glucan from S. mutans.

Animals↗

PubMed1989

DNA homology of surface protein antigen A gene in mutans streptococci.

1. A recombinant plasmid, pYA724, containing an 8.45 kb DNA fragment encoding surface protein antigen A (spaA) from Streptococcus sobrinus 6715 was used to examine the DNA homology of the spaA gene with chromosomal DNA of various mutans streptococci strains. 2. Restriction endonuclease BamHI-digested pYA724 DNA was radio-labeled by nick-translation, and a DNA-DNA hybridization experiment was carried out. pYA724 DNA hybridized with chromosomal DNA of serotypes a, c, d, e, f and g strains, but not with b by dot DNA-hybridization and Southern blot DNA hybridization. 3. Chromosomal DNAs were isolated from several serotype c Streptococcus mutans strains, digested with BamHI, and analyzed by Southern blot DNA hybridization. pYA724 DNA hybridized with different sizes and numbers of BamHI-digested DNA fragments of the chromosomal DNAs. 4. These data indicated that all mutans streptococci strains except serotype b have DNA homologous with the spaA gene, although within the same serotype strain the spaA gene has a diversity of arrangement within the chromosome.

Antigens, Bacterial↗

PubMed1989

Cloning of mercury-resistance gene from R-plasmid in Escherichia coli isolated from dental hospital sewage.

1. Mercury-resistance gene was cloned from a drug-resistance plasmid in Escherichia coli isolated from dental hospital sewage. 2. A 7.7 kb mercury-resistance gene was successfully cloned and expressed in pJC74 cosmid and pBR 322 plasmid vectors. 3. High activities of mercury reductase and 203Hg vaporization were demonstrated in cell extracts of mercury-resistant clone. 4. Mercury reductase activity was localized in the cytoplasm. 5. By colony DNA-DNA hybridization, 32P-labelled 7.7-kb DNA hybridized with mercury-resistant E. coli isolates from dental hospital sewage.

Cloning, Molecular↗

PubMed1989

Purification and characterization of glycylprolyl aminopeptidase from Bacteroides gingivalis.

A glycylprocyl aminopeptidase from cell extracts of Bacteriodes gingivalis 381 was purified 1058-fold by hydrophobic adsorbent, HPLC anion exchange, and HPLC gel filtration column chromatography. The final enzyme preparation was homogeneous with a molecular weight of 75,000 daltons by SDS-PAGE, and the isoelectric point was 6.2. The optimum pH of the enzyme was 8.0, and the enzyme activity was inhibited by DFP Ni2+ and Hg2+.

Aminopeptidases↗

PubMed1989

A cytochemical study of dense granules in the rat junctional epithelium.

To clarify the details of intracytoplasmic granules in the junctional epithelium (JE) of the rat gingiva, phosphotungstic acid (PTA) staining, acid phosphatase cytochemistry and zinc iodide-osmium (ZIO) staining were carried out. Condensing granules containing homogeneous electron-dense materials, measuring about 260 nm in diameter, have been observed at the peripheral cytoplasm of the JE. These granules reveal PTA-positive, ZIO-positive and acid phosphatase-positive staining. These results indicate that the granules contain glycoprotein, phospholipid, lipoprotein and lysosomal enzymes. From their composition and morphology, it is suggested that these granules in the JE may contribute secretory function and secrete glycoproteins or glycolipids. Although it is unclear whether the dense granules correspond to membrane-coating granules by our staining methods, it is surmised that, if the dense granules can engage in establishment of the barrier function, then this role is impeded by the large intercellular space in the JE.

Acid Phosphatase↗

PubMed1989

Attenuation of ischaemia-induced regional myocardial acidosis by bevantolol, a beta 1-adrenoceptor antagonist, in dogs.

In dogs anaesthetized with pentobarbital, the left anterior descending coronary artery (LAD) was occluded for 90 min. so that about 1/2 of the original flow was allowed to flow (partial occlusion). Bevantolol (a beta 1-adrenoceptor antagonist) or propranolol (a reference drug) was injected intravenously 30 min. after partial occlusion. Regional myocardial pH was measured by a micro glass pH electrode inserted in the LAD area. Partial occlusion decreased myocardial pH by 0.62 to 0.74. Bevantolol (1.0 mg/kg) or propranolol (1.0 mg/kg) significantly increased myocardial pH, that had been decreased by partial occlusion, within 60 min. after the injection. Restoration of myocardial [H+] (defined as return towards a lower [H+] to the preocclusion level) (calculated from the pH data) induced by bevantolol and that induced by propranolol were 64.0 and 66.4% (measured 60 min. after the injection), respectively. Bevantolol or propranolol decreased heart rate also. Even in the paced heart, bevantolol restored the myocardial [H+] that had been increased by partial occlusion. These results suggest that bevantolol has a favorable effect on the ischaemic myocardium as has propranolol, and that the pH effect of bevantolol is not primarily due to a decrease in heart rate.

Acidosis↗

PubMed1989

[Chemosensitivity of human head and neck tumors detected by human tumor clonogenic assay].

Chemosensitivity of human head and neck tumor was evaluated by human tumor clonogenic assay. Among eight of head and neck tumors seven squamous cell carcinomas such as tongue, gingiva, maxillary sinus, pharynx and one malignant fibrous histiocytoma (MFH) of maxillary sinus and four anti-cancer agents BLM, CDDP, 5-FU and MMC were used. Five of eight tumors were succeeded to evaluate the sensitivity. Positive rates except MFH were BLM 100% (3/3), CDDP 25% (1/4), 5-FU 33% (1/3). These results are similar to recent clinical experiments except CDDP.

Bleomycin↗

PubMed1989

[Radio- and radio-chemosensitivity of human head and neck cancer cell line detected by human tumor clonogenic assay].

The radiosensitivity and radio-chemosensitivity of 3 series of human cancer cell lines were evaluated by human tumor clonogenic assay. The sources of cell lines were gingiva carcinoma (Ca9-22), uterus carcinoma (Hela) and gastric carcinoma (MKN-45). BLM and CDDP were used, and chemosensitivity of gingiva carcinoma tended to be higher than other cell lines. Radiosensitivity was same as MKN-45. Isobologram were employed for quantitation of the interaction between the irradiation and anti-cancer agents. In Ca9-22, the interaction of between gamma-rays, BLM and CDDP was supra-additive. Hela was also supra-additive, but in MKN-45, the interaction of between gamma-rays and BLM was sub-additive.

Bleomycin↗

PubMed1989

[Histopathological study of experimental periodontitis in rats--ultrastructures, permeability, immunohistochemistry, and morphometric analysis in both pocket and long junctional epithelial].

UNLABELLED: To elucidate the biological characteristics of both pocket and long junctional epithelia in experimental periodontitis, elastic rubber was inserted between the first and second molars of the left maxilla in rats. The rubber was removed after a week. An immunohistochemical study using anti-laminin and permeability experiments using peroxidase were conducted; examinations were made of ultrastructures and lanthanum; and a morphometric analysis was made of the distribution of capillaries immediately below the epithelium. RESULTS: 1. Periodontal pockets formed from 5 days to 2 weeks after removal of the rubber. The long junctional epithelium was appearent from the fourth week after removal. Immunohistochemical study showed that laminin was located at the internal and external basal laminae in the long junctional epithelium but not on the surface of the pocket epithelium. 2. Electron microscopy showed the pocket epithelium to consist of flattened cells aligned parallel to the tooth surface in the coronal portion. The epithelium, which included numerous vacuoles, manifested especially wide intercellular spaces in which a large number of polymorphonuclear leukocytes were evident. Bacteria surrounded by neutrophils could be seen on the surface of the cementum in the pocket. Invading neutrophils split the epithelium at the central portion of the pocket. In the apical portion, the epithelium formed spindles that adhered to the cementum by means of half-desmosomes. Many neutrophils and fenestrated capillaries were observed in connective tissue immediately below the epithelium. 3. The long junctional epithelium consisted of 2 or 3 cell layers aligned parallel to the tooth surface. Intercellular spaces in the long junctional epithelium were as wide as those in the pocket epithelium and contained a small number of lymphocytes and a few neutrophils. Half-desmosomes were detected between the epithelial cells and the cementum. From the central to the apical region, epithelial tissues assumed a knife-edge form. Desmosomes and gap junctions occurred among these cells. Dense granules containing a limiting membrane and homogeneous electron-dense material were observed int he peripheral cytoplasm. Although fibroblasts aligned parallel to the epithelium occurred in them, few collagen fibers, inflammatory cells and capillaries were to be recognized in the connective tissue. 4. Permeability experiments in the pocket and the long junctional epithelium produced analogous results. Light microscopy showed that, in both epithelia, peroxidase penetrated into intercellular spaces and leaked into the pocket. Electron microscopy showed that, as an electron-dense material, lanthanum was detected in intercellular spaces and connective tissues.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1989

[Effect of diglyceride on phospholipase A2 activities in plasma membrane of guinea pig peritoneal macrophases].

The AA release from phospholipids is believed to be controlled by the activation of phospholipase A2 which are probably localized in the plasma membranes. And the considerable interest has been focused on the study of cells of the immune system including macrophages which metabolize arachidonic acid (AA) to prostaglandins, thromboxanes and leukotriens. Recently, it has been reported that phosphatidylinositol (PI) turnover plays an important role in the response to external stimuli in these cells. PI turnover has been accepted as being initiated by the hydrolysis of PI which is catalyzed by the phospholipase C and produced AA. Recently, we demonstrated that PI-specific phospholipase A2 in macrophage plasma membrane directly acted for AA release from PI. On the other hand, diglyceride, which is produced from PI by phospholipase C activation, is known to regulate the several cell functions with a protein kinase C activation. In this report, we examined the effect of diglyceride on phospholipase A2 activities in macrophage plasma membrane. PI-phospholipase A2 and PC-phospholipase A2 activities were stimulated by the addition of diglyceride. In contrast, PE-phospholipase A2 was not affected by diglyceride addition. The results suggested that phospholipase A2 activation was occurred with coupling the diglyceride production via the phospholipase C pathway.

Arachidonic Acid↗

PubMed1989

Nipradilol, a beta-adrenoceptor antagonist having a vasodilatory action, attenuates myocardial acidosis induced by coronary artery occlusion in dogs.

In dogs anesthetized with pentobarbital, the anterior descending coronary artery (LAD) was partially occluded to reduce LAD flow to about half of the original flow (partial occlusion). Myocardial pH (MpH) was measured by the use of a micro glass pH electrode. MpH decreased from 7.5-7.63 to 6.82-6.86 30 min after partial occlusion of the LAD. Nipradilol (0.3 mg/kg) was injected intravenously 30 min after partial occlusion, which continued for a further 60 min after nipradilol injection. Nipradilol decreased blood pressure and heart rate, and significantly increased myocardial pH which had been decreased by partial occlusion, within 60 min after injection. Nipradilol-induced restoration of the myocardial [H+] (calculated from the pH data), that had been increased by partial occlusion, was 48.5%. Bradycardia induced by nipradilol was not a determinant factor in the pH effect of nipradilol, because even in the paced heart, nipradilol restored the myocardial [H+] that had been increased by partial occlusion. These results indicate that nipradilol attenuates ischemia-induced myocardial acidosis, suggesting the favorable effect of nipradilol on ischemic myocardium. The favorable effect of nipradilol may be due to the beta-adrenoceptor antagonistic effect rather than the vasodilating effect.

Acidosis↗

PubMed1989

Relationship between coronary flow and high energy phosphates in the isolated perfused rat heart, with special reference to the effects of anoxia, iodoacetic acid, and 2,4-dinitrophenol.

In Langendorff rat hearts, anoxia increased the coronary flow, concentration of adenosine in the coronary effluent and the tissue level of lactate, and decreased the intracellular oxygen, left ventricular pressure (LVP), heart rate and the tissue levels of adenosine triphosphate (ATP) and creatine phosphate (CrP). In the normoxic heart, an infusion of iodoacetic acid (IAA) (0.1 mg/min) increased the coronary flow, adenosine concentration in the effluent, and decreased ATP and CrP levels, without decreasing the intracellular oxygen. When glucose in the perfusate was substituted for pyruvate, IAA did not produce the pharmacological effects. In the normoxic heart, an infusion of 2,4-dinitrophenol (DNP) (50 micrograms/min) increased the coronary flow, adenosine concentration in the effluent and oxygen consumption, but decreased the intracellular oxygen, LVP and the tissue levels of ATP and CrP, without affecting the lactate level. There was no direct relationship between the coronary flow and the adenosine concentration in the effluent, but there was a close relationship between the increase in coronary flow and the total loss of myocardial ATP and CrP during anoxia, infusion of IAA, or infusion of DNP. These results indicate that the total loss of ATP and CrP from the myocardium (and hence energy state of the myocardium) may be responsible for regulation of coronary flow.

2,4-Dinitrophenol↗

PubMed1989

Diversity of surface protein antigen A gene in the chromosomal DNA of Streptococcus sobrinus.

A recombinant plasmid, pYA724, containing an 8.45-kb DNA fragment encoding surface protein antigen A (spaA) from Streptococcus sobrinus 6715 was used to examine the DNA homology of the spaA gene with chromosomal DNA of Streptococcus sobrinus B13N. Restriction endonuclease BamHI-digested pYA724 DNA was 32P radio-labeled by nick-translation, and a Southern blot DNA-DNA hybridization experiment was carried out. pYA724 DNA hybridized with a BamHI fragment of B13N chromosomal DNA, and the size of this fragment was larger than 8.45 kb. The chromosomal DNA was digested with BamHI-Pst I, BamHI-Hind III, and BamHI-Sal I, and analyzed by Southern blot DNA hybridization. pYA724 DNA hybridized with different sizes and numbers of DNA fragments of B13N chromosomal DNA; however, the sizes were not identical to those of internal fragments expected from the pYA724 restriction map. SpaA gene clone derivative plasmids, pYA745 and pYA756, were digested with EcoRI and Hinc II, respectively, and electrophoresed together with the digested B13N chromosomal DNA on the same gel; then Southern blot analysis was carried out. Fragments with sizes corresponding to the EcoRI or HincII internal fragments of pYA745 and pYA756 were not observed among the B13N fragments. These data indicate that serotype d S. sobrinus B13N has DNA homologous with the spaA gene from serotype g strain 6715, although within the same biotype strain has a diversity of arrangement within the chromosome.

Antigens, Bacterial↗

PubMed1989

Ultrastructure of basal cell adenoma in the parotid gland.

Basal cell adenoma of the parotid gland was studied with electron microscopy. The cells constituting this tumor were divided into three types of epithelial cells; ductal, myoepithelial, and squamous cells. The ductal cells, which were polygonal and cuboidal in shape, formed a sometimes distinct lumen. Glycogen were recognized in the cytoplasm of these cells. The myoepithelial cells appeared as plasmacytoid cells which contained abundant microfilaments. The squamous cells were characterized by the presence of well-developed tonofilaments and desmosomes. However, no secretory cells could be found, although small, electron dense granules were detected in the cytoplasm of the ductal cells. The granules were unlike secretory granules in their size, number and location. In consideration of the presence of secretory and myoepithelial cells, we reviewed previously reported literature and discussed the identification of secretory granules. From our and other reported results, we tentatively concluded that the electron dense granules described as secretory granules are not intrinsic secretory granules. Further, we suggested that the cell types and the histogenesis of basal cell adenoma are analogous to those of both pleomorphic and clear cell adenomas.

Adenoma↗