Search PubMed⌕ Search

Biomedical subjects

T Miyata

Publications and source records attributed to T Miyata.

At least 559 records · Page 31Linked to original sources
PubMed1989

Increased production and/or secretion of pulmonary surfactant in rats by long term sulfur dioxide exposure.

Influence of long term SO2 exposure on the pulmonary surfactant in rats was studied by means of chemical analysis and microscopic verification. At a time after termination of the exposure period, the general symptom in rats was similar to that of bronchitis. The content of disaturated phosphatidylcholine, a main functional component of the pulmonary surfactant, significantly increased not only in broncho-alveolar lavage fluid but also in pulmonary microsomal fraction by long term SO2 exposure. Microscopic verification of alveolar type II cells from the bronchitic rats demonstrated the development of rough surface endoplasmic reticulums and an increase of the number of osmiophillic bodies. The results suggest that pulmonary surfactant production and/or secretion are activated in rats with bronchitis caused by long term SO2 exposure.

Animals↗
PubMed1989

Protective effect of surface-active phospholipids against the acid-inducing inhibition of the tracheal mucociliary transport.

Little is known about the physiological role of surface active phospholipids (SAP) in the central respiratory tract. In the present study, the effect of SAP on acid-inducing inhibition of particle transport by the tracheal mucociliary function was investigated in unanesthetized pigeons. SAP and acids were directly nebulized to the surface of the trachea. The composition of SAP was based on that of the pulmonary surfactant. The experiment was carried out under application of acetylcholine providing a constant mucociliary transport. SAP significantly diminished HCl- and H2SO4-inducing inhibitions of the mucociliary transport. Benzalkonium chloride also reduced the inhibition. The results suggest that SAP may be a protecting factor of the mucociliary clearance and that SAP may be connected with hydrophobicity not only of the alveolar surface but of the tracheal epithelium.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1989

Effects of anticholinergic bronchodilators on mucociliary transport and airway secretion.

The effects of atropine, ipratropium and oxitropium on the mucociliary clearance were studied in pigeons and rabbits. The normal mucociliary transport (MCT) in pigeons was inhibited after the treatment by any of the three drugs at concentrations of 10(-4) to 10(-3) g/ml. These three drugs markedly inhibited eserine-induced MCT acceleration at a lower concentration than ACh-induced acceleration. The normal airway secretion was inhibited only by atropine in rabbits. The results indicate that neither oxitropium nor ipratropium depress the normal mucociliary clearance, but atropine may depress it under some conditions. Additionally, we suggest that these anticholinergic drugs might selectively affect the mucociliary transport modulated by endogenous ACh.

Acetylcholine↗
PubMed1989

Different cross-linked types of collagen implanted in rat palatal gingiva.

Collagen membrane preparations were manufactured with the aim of enhancing wound healing following periodontal surgery. After crosslinking by various processing methods (with ultraviolet and hexamethylenediisocyanate) and to various extents, two types of collagen (atelocollagen and tendon collagen) were implanted into a dissection site within palatal gingival tissue. The time course of healing responses was investigated histologically. Collagen implantation was found to accelerate fibrous connective tissue attachment to the root surface and inhibit apical migration of the junctional epithelium. Cross-linked atelocollagen was superior in biocompatibility to the other collagen membranes studied.

Animals↗
PubMed1989

[Maintenance and the clinical evaluation of periodontal patients in Konus-Telescope denture].

In order to assess by periodontal evaluation the changes that might occur with time in the abutment teeth and periodontal tissues when Konus-Telescope dentures are used as that final treatment of periodontal disease, the dentures (15 units) were placed in 13 patients with missing tooth and periodontal disease and findings at the time of denture placement and 30 months after the placement were compared. The number of cases that exhibited significant changes in hygiene level, tissue inflammation and periodontal pocket depth of the abutment teeth after 30 months was very small, while as many as 85.2% of the abutment teeth showed decrease in tooth mobility. Increase in tooth mobility was not detected in any of the cases. In addition, X-ray examination revealed tendencies toward improvement of the periodontal ligament and remission of alveolar bone resorption in many of the cases. These results suggest that Konus-Telescope denture is highly offers protection of the residual periodontal tissues through its secondary splint action.

Bone Resorption↗
PubMed1989

Endotoxemia and human liver transplantation.

Ninety liver transplantations were performed in 81 patients. Plasma endotoxin was measured preoperatively, at the end of the anhepatic phase, and on postoperative days 1, 3, and 7. The presence of high endotoxin levels preoperatively and at the end of the anhepatic period was associated with graft failure and a high mortality. Patients with primary nonfunction of their transplants typically had severe endotoxemia. Endotoxemia could be a cause rather than an effect of perioperative complications and graft loss.

Alanine Transaminase↗
PubMed1989

[The effectiveness of GaA1As semiconductor laser treatment to pain decrease after irradiation].

Recently, sedative and antiphlogistic treatment is conducted with low energy laser irradiation. The purpose of the this study was to evaluate the effectiveness to decrease of pain just after irradiation by a GaA1As semiconductor laser. The irradiation apparatus was SEMI LASER NANOX (LX-800: G-C. Co.) with the following features: a wave length of (around) 780nm: the laser energy, 30mW; exposure time, 30sec to 180sec/per treatment. Diagnosis of pre- and post-operative sensitivity were classified into the following four grades: Grade 0 no pain. Grade I mild pain. Grade II strong but tolerable pain. Grade III intolerable pain (simultaneous with stimulation). The results were as follows: 1. In the hypersensitivity of dentin, the treatment was not effective with 2 cases of grade III, but with all of grade I, II (35 cases) the pain decreased just after irradiation. 2. It was effective in all cases with pain like periodontitis after root canal filling and pain after extraction of teeth. 3. It was effective in all cases with gingivitis, stomatitis, and gingival ulcers after infiltration anesthesia etc..

Adolescent↗
PubMed1989

[Simulation with a pre-clinical training system. 2. Evaluation of the pre-clinical training system].

This study evaluated usefulness of the Pre-Clinical Training System. Undergraduate students and instructors at Higashi-Nippon-Gakuen University practiced class I composite resin restoration of the lower right first molar using the system. After the practice, they filled out questionnaires to evaluate the system. According to the results, this system proved useful for pre-clinical education though there is room for improvement.

Dental Restoration, Permanent↗
PubMed1989

Rat mesangial cells actively produce phosphatidylinositol-anchored Thy-1.

We provide evidence that the mesangial cells of rat kidney glomeruli express Thy-1 as a phosphatidylinositol-anchored protein. Both the mesangial area of kidney, examined in tissue sections, and mesangial cells maintained in culture for more than 3 months, showed prominent immunofluorescence staining with an anti-Thy-1 monoclonal antibody (OX7); this staining was almost completely abolished by pretreating kidney sections or mesangial cells with the phosphatidylinositol-specific enzyme, phospholipase C. By Northern blotting, mesangial cells were shown to express mRNA of an appropriate size, hybridizing to a mouse Thy-1.1-specific probe.

Animals↗
PubMed1989

[Antitussive effects of Bakumondô-tô and codeine in bronchitic guinea-pigs].

Antitussive effects of Bakumondô-tô and codeine were examined in bronchitic guinea-pigs made by an exposure to SO2. Bakumondô-tô significantly depressed the cough reflex induced by mechanical and chemical stimulations in the bronchitic but not in the normal animals. Repeated administration of Bakumondô-tô significantly suppressed the increased spontaneous discharge of the superior laryngeal nerve in bronchitic animals. On the other hand, the antitussive action of codeine in bronchitic animals was significantly weaker than that in normal animals. Moreover, repeated administrations of codeine significantly potentiated the increased spontaneous discharge of the superior laryngeal nerve. The results suggest that Bakumondô-tô, unlike codeine, has a notable antitussive activity in bronchitic rather than in normal guinea-pigs.

Animals↗
PubMed1989

[Basic studies on hard direct reline resins. Part 1. Adhesive strength].

Direct relining methods has come to occupy an important position in removable denture prosthodontics. The purpose of this study was to investigate the effect of various experimental conditions on the adhesive strength of hard direct reline resins to denture base resin. The experimental conditions were as follows: 1) immersion time of denture base resin before relining, 2) amount of load at relining, 3) roughness of adhesive surface, 4) immersion time of relined resin. The following results were obtained: 1. The adhesive strength of Rebaron was the highest, followed by that of TRIAD and KOOLiner. 2. The immersion times of denture base resin did not appreciably affect the adhesive strength. 3. With the rougher adhesive surface, Rebaron and KOOLiner showed a tendency to increase adhesive strength. 4. The adhesive strength was not appreciably affected by load. 5. We did not find a definitive correlation between adhesive strength and immersion times of relined resin.

Adhesiveness↗
PubMed1989

[Piperidine in the brain: its neurobiological significance].

Piperidine (Pip) is a normal constituent in mammalian brain, affects synaptic mechanism in the CNS, and influences neural mechanisms governing regulation of emotional behavior and extrapyramidal function. In addition, there are enzyme systems within the brain that synthesize and metabolize Pip, and uptake and storage mechanisms for Pip are found in the nerve endings. Pip is highly concentrated in the pituitary and pineal glands, hippocampus and caudate nucleus among the regions of the brain. Levels of Pip in the brain show physiological variations associated with environmental changes. The levels increase significantly under deep anesthesia. The study on the time relations of the change in brain levels of Pip and the anesthetic activity demonstrates that the level increases prior to the loss of the righting reflex and that the elevated level declines prior to the reappearance of the reflex. Furthermore, Pip levels in the lower brainstem reticular formation show sleep-related changes during REM sleep deprivation and REM sleep rebound that followed. Direct administration of Pip into the hippocampus and amygdala of cats with chronically implanted electrodes and a cannula caused resting and calmness in small doses, and seizure discharge accompanied by hyperemotionality in large doses. Administration into the pontine reticular formation induced REM and NREM sleep. Iontophoretic application produced the excitation and inhibition of single neuron activities in the cerebral cortex, hippocampus, caudate nucleus, cerebellum, and pituitary in anesthetized rats. With no anesthesia, Pip caused the inhibitory action in a higher percentage of the neurons studied, compared with the result obtained under anesthesia. Pip-induced excitation and inhibiton were blocked by tetramethylammonium but little affected by scopolamine. The kinetic study of Pip-induced Cl- current in internally perfused neurons of Aplysia, by using the 'concentration camp' and voltage clamp techniques, revealed that Pip acted on at least two components of nicotinic receptor-Cl- channel complex, and further that Pip could discriminate between the transient and the persistent components of ACh-induced Cl- current. These findings suggest that Pip may have close connections with neuroendocrine as well as neuronal functions, and further, with the mechanisms underlying sleep-consciousness and emotional function. Because of piperidine's multiplex pharmacological activities, the study of piperidine may provide a clue to the discovery of new active drugs and to the elucidation of causes of pathological states relating to the brain function.

Anesthesia↗
PubMed1989

[Late results and clinicopathological study of vein graft failure in infrainguinal arterial reconstruction].

Long-term follow-up study of 79 infrainguinal arterial bypasses with autogenous vein graft in 62 patients was undertaken to clarify the cause of late graft occlusion. Thirty grafts failed during the follow-up period, including 7 early and 23 late occlusions. The overall cumulative patency rate at 5 years was 58.6%. The analysis of angiograms of 33 limbs revealed the long-term morphological changes which included 1 occlusion of the femoral artery proximal to the vein bypass, 8 graft stenosis, and 5 atherosclerotic progressions of the outflow tract. The causes of 8 graft stenoses consisted of 5 anastomotic intimal hyperplasia (ANIH), 2 atherosclerotic changes, and 1 external compression of the graft by tendons. All of four histologically examined stenosed anastomoses had marked peri-anastomotic fibrosis, which was suspected to be caused by extensive circumferential dissection of the host artery at the initial operation. In 3 stenosed anastomoses with arteriosclerosis obliterans, the luminal diameter was the narrowest at the arterial side with intimal hyperplasia over remnant atheromatous lesion. In conclusion, ANIH is the most influential cause of graft occlusion, and perianastomotic local factors such as initial anastomotic deformity, periarterial fibrosis, and remnant arterial lesion at anastomosis, revealed to have much influence on the cause of ANIH.

Adult↗
PubMed1988

The factor V-activating enzyme (RVV-V) from Russell's viper venom. Identification of isoproteins RVV-V alpha, -V beta, and -V gamma and their complete amino acid sequences.

The complete amino acid sequences of two isoproteins of the factor V-activating enzyme (RVV-V) isolated from Vipera russelli (Russell's viper) venom were determined by sequencing S-pyridylethylated derivatives of the proteins and their peptide fragments generated by either chemical (cyanogen bromide and 2-(2-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine) or enzymatic (trypsin, alpha-chymotrypsin, and lysyl endopeptidase) cleavages. Both enzymes, designated RVV-V alpha and RVV-V gamma, consist of 236 amino acid residues and have a N-linked oligosaccharide chain at Asn229. The six amino acid substitutions between RVV-V alpha and -V gamma are: Thr22(alpha)-Ala22(gamma), Gly29(alpha)-Ala29(gamma), Gln191(alpha)-Glu191(gamma), Ile192(alpha)-Met192(gamma), Gln193(alpha)-His193(gamma), and Asn224(alpha)-Ser224(gamma). The molecular weights were calculated as 26,182 for RVV-V alpha and 26,167 for RVV-V gamma. The sequences of the RVV-V isoproteins exhibited 62% identity with that of batroxobin, a thrombin-like enzyme present in Bothrops atrox venom, and 33% identity with that of human thrombin B chain. The most interesting difference between the structures of RVV-V and other trypsin-type serine proteases is that the conservative Ser214-Trp215-Gly216 sequence (chymotrypsinogen numbering), considered as the site of antiparallel beta-sheet formation between the protein substrate and most serine proteases, has been replaced by the corresponding sequence Ala-Gly-Gly.

Amino Acid Sequence↗
PubMed1988

Tachyplesin, a class of antimicrobial peptide from the hemocytes of the horseshoe crab (Tachypleus tridentatus). Isolation and chemical structure.

A cationic peptide, designated tachyplesin, was isolated from acid extracts of horseshoe crab (Tachypleus tridentatus) hemocyte debris. It consists of 17 residues and the structure determined by Edman degradation is: (formula; see text) The carboxyl-terminal end of this peptide was identified as arginine alpha-amide, and the whole sequence including the alpha-amide was also confirmed by fast atom bombardment mass spectrometry, indicating a mass value of 2263. Tachyplesin inhibits growth of both Gram-negative and -positive bacteria at low concentrations and formed a complex with bacterial lipopolysaccharide. Tachyplesin seems likely to act as antimicrobial peptide for self-defense in the horseshoe crab against invading microorganisms.

Amino Acid Sequence↗
PubMed1988

Bovine factor VII. Its purification and complete amino acid sequence.

A modified method for purification of blood clotting factor VII from bovine plasma was developed, and its complete amino acid sequence was established. The isolated factor VII was activated with factor XIIa, and the resulting two-chain factor VII (factor VIIa) was reduced and S-pyridylethylated or S-aminoethylated. The amino acid sequences of the S-alkylated heavy and light chains were determined by sequencing the fragments obtained from enzymatic and chemical cleavages. Fast atom bombardment mass spectrometry was also used to establish the COOH-terminal sequence of the heavy chain. The light chain consists of 152 residues with one carbohydrate chain at Asn145, and 11 gamma-carboxyglutamic acid residues are found within the NH2-terminal 35 residues. The light chain contains 0.2-0.3 mol of beta-hydroxyaspartic acid/mol of protein, indicating that an aspartic acid residue in bovine factor VII is incompletely hydroxylated. Moreover, a pentapeptide, Ala-Ser*-Ser-Pro-Cys (positions 51-55), isolated from an enzymatic digest of the light chain, contained an unknown serine derivative, but its structure is still unclear. On the other hand, the heavy chain is composed of 255 residues and one asparagine-linked carbohydrate chain at Asn203. Bovine factor VII, with a total of 407 residues, has 71% sequence identity with the human molecule (406 residues) predicted from the cDNA sequence (Hagen, F. S., Gray, C. L., O'Hara, P., Grant, F. J., Saari, G. C., Woodbury, R. G., Hart, C. E., Insley, M., Kisiel, W., Kurachi, K., and Davie, E. W. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 2412-2416).

Amino Acid Sequence↗
PubMed1988

Substitution of gamma Arg-275 by Cys in an abnormal fibrinogen, "fibrinogen Osaka II". Evidence for a unique solitary cystine structure at the mutation site.

In an abnormal fibrinogen with impaired fibrin monomer polymerization designed as fibrinogen Osaka II, we have identified substitution of Arg by Cys at position 275 of the gamma chain. This Cys is linked to a free cysteine molecule by a disulfide link as evidenced by fast atom bombardment mass spectrometry. This finding was supported by identification of a single cysteine released from isolated abnormal fragment D1 upon reduction. This unique cystine structure at the mutation site has not been reported heretofore in any abnormal protein including fibrinogen. The substitution may well perturb the structure required for fibrin monomer polymerization, specifically that assigned to the carboxyl-terminal D domain of fibrinogen. Indeed, isolated fragment D1 with the Cys substitution failed to inhibit thrombin-mediated clotting of normal fibrinogen and normal fibrin monomer polymerization, while normal fragment D1 inhibited them markedly. Our data seem to provide supporting evidence that the putative polymerization site(s) assigned to the D domain of fibrinogen may be structure-dependent, including the carboxyl-terminal segment of the gamma chain as well as a contiguous region that contains the gamma 275 residue.

Adolescent↗