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Y Terada

Publications and source records attributed to Y Terada.

At least 181 records · Page 10Linked to original sources
PubMed1996

Reconstruction of two-dimensional current distribution from tangential MCG measurement.

We describe a two-dimensional reconstruction method for tangential magnetocardiograms (MCGs). This method is based on two-dimensional Fourier analysis, and we used a new type of window function for tangential MCG to solve the problem of the small number of measurement points. By using this method, cardiac activity can be estimated as a two-dimensional current distribution. To determine the effectiveness of this method, we measured tangential MCGs of normal subjects, and compared the estimated current distribution with the actual cardiac muscle activity. Using this method, we were able to clearly show cardiac activity.

Adult↗
PubMed1996

Expression of growth hormone receptor in mouse preimplantation embryos.

Growth hormone (GH) is believed to be involved in reproductive function. Recent reports demonstrate the presence of the growth hormone receptors (GHR) in reproductive organs and fetal tissues suggesting that the contribution of GH to reproductive phenomena may be mediated through GHR. In this study we assessed the expression of GHR in mouse preimplantation embryos using immunofluorescent staining with a monoclonal antibody directed against GHR. The messenger RNA (mRNA) for GHR was investigated in mouse preimplantation embryo by reverse transcription-polymerase chain reaction (RT-PCR). The anti-GHR monoclonal antibody Mab 263 was detected by immunofluorescent staining after the compaction of the morula stage. GHR mRNA transcript was identified in 8-cell stage embryos. Our findings indicate that GHR is localized in mouse preimplantation embryos, and suggests that GH has a direct effect on preimplantation embryos mediated by GHR.

Animals↗
PubMed1996

Role of urinary arginine vasopressin in the sodium excretion in patients with chronic renal failure.

Patients with chronic renal failure show almost equal levels of sodium excreted in the urine as healthy subjects through an increase of the fractional excretion sodium (FE(Na)). The mechanisms of this adaptation, however, are unknown. Recently, urinary arginine vasopressin (AVP) has been shown to inhibit the antidiuretic action of plasma AVP in the collecting ducts of rabbits and rats. In this article, the roles of plasma and urinary AVP are examined with other hormones in the sodium excretion of 57 patients with chronic renal disease. The fractional excretion of AVP, plasma atrial natriuretic peptide (ANP) and endothelin-1 (ET-1), urinary ET-1, and FE(ET-1) correlated with the decrease of creatinine clearance (Ccr). Multiple and stepwise regression analyses showed that FE(AVP) is the major dependent determinant for FE(Na) (adjusted r2 = 0.78). These results suggest that the increase of AVP excretion per remaining nephron could be a cause of the increase of FE(Na) in patients with renal failure. Although plasma AVP works as an antidiuretic hormone, urinary AVP serves as an intrinsic diuretic, especially in patients with chronic renal failure.

Adolescent↗
PubMed1996

Inhibition of advanced protein glycation by 8-quinolinecarboxylic hydrazide.

Glycation of proteins is belived to be involved in the pathogenesis of diabetic complications, and thus the development of potent inhibitors of protein glycation is highly desirable. We tested the inhibitory effects of 12 hydrazide compounds against protein glycation and compared them with the effects of aminoguanidine (AG), a well-known inhibitor. When bovine serum albumin (BSA) was incubated with 100 mmol/l mannose for 10 days at 37 degrees C in the presence and absence of hydrazide compounds or AG at 1 mmol/l, only p-anisic hydrazide inhibited Amadori product formation. On the other hand, 8 hydrazides as well as AG inhibited the formation of advanced glycation end products (AGEs). 8-Quinolinecarboxylic hydrazide (8-QCH), the most potent hydrazide, was more effective than AG. Neither 8-QCH nor AG affected the spontaneous decrease in Amadori products of preglycated BSA in the absence of sugar, but suppressed the spontaneous increase in AGEs from preglycated BSA, with higher potency of 8-QCH relative to AG. The results indicate that 8-QCH is a more potent inhibitor of AGE formation than AG and suggest that the inhibition mechanisms of 8-QCH and AG resemble each other.

Glycoproteins↗
PubMed1996

An ultrastructural study of the relationship between sensory trigeminal nerves and odontoblasts in rat dentin/pulp as demonstrated by the anterograde transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP).

Because the ultrastructure of the trigeminal sensory nerves in dentin, especially in relation to odontoblasts, remains to be clarified, we investigated the relationship between the trigeminal sensory nerves and the odontoblast processes using the anterograde axonal transport technique by injecting wheat germ agglutinin-horseradish peroxidase (WGA-HRP) into the rat trigeminal ganglion. Light microscopically, the nerves labeled with WGA-HRP were mainly concentrated at the pulpal horn, forming a nerve plexus at the subodontoblastic region and penetrating the predentin/dentin about 50 to 70 microns. Ultrastructurally, HRP reaction products were observed intra-axonally in the myelinated (A delta) and unmyelinated (C) axons in the subodontoblastic region. Most nerves lost the Schwann sheath and were naked in the predentin/dentin. The labeled varicosities were close to the odontoblast processes in the dentinal tubules. No synaptic structures could be detected between the varicosities and the odontoblasts, but a gap about 20 nm wide was found between them. One type of varicosity was a rich mitochondria-containing varicosity, while the other was a rich vesicle-containing (large dense core vesicles and small clear vesicles) one. The reaction products were also found in the extracellular spaces surrounding the axons. Sometimes the reaction products were seen in the coated pits or the endocytotic vesicles of the odontoblast processes. The present study demonstrated that nerve endings (varicosities) derived from the trigeminal ganglion were present in the dentinal tubules, and that WGA-HRP extracellularly extruded from the sensory nerves in the odontoblastic layer or predentin/dentin. These findings thus suggest that sensory nerves may have some (e.g., trophic) effect on either odontoblasts or the environment around the sensory nerves in the dentin/pulp.

Afferent Pathways↗
PubMed1996

[Effect of formation of surface complex between hydroxypropylcellulose and sodium dodecylsulfate on dispersion/flocculation of O/W-type emulsion of soybean oil].

An O/W-type emulsion of soybean oil (theta v = 0.05) was prepared in the presence of various concentrations of hydroxypropylcellulose (HPC) and sodium dodecylsulfate (SDS). The mean diameter (d) of secondary particles of the oil droplets decreased with concentrations of SDS and HPC after attaining a maximum at [SDS] = 5 mmol/dm3 and [HPC] = 10(-3) g/dl, while the relative viscosity (eta rel) of the emulsion increased with an SDS concentration after attaining a minimum around 5 mmol/dl3 when the HPC concentration was kept constant. These facts were explained in terms of the formulation of a surface complex by hydrophobic interaction between SDS and HPC adsorbed on the surface of the droplets. When the concentration of SDS is low, it bridges between the HPC segments intra- and intermolecularly on and between the particles, resulting in shrinking of the HPC surface layers as well as in bridging among the particles. Therefore, the total volume of the secondary particles effective on eta rel decreases while the d-value increases with the SDS concentration. When the concentration becomes high, binding ratio of SDS to HPC also increases and the segments are repulsive each other owing to the negative charges given by the bound SDS. As a result, the adsorption layer swells and the secondary particles are redispersed. This fact causes an increase in eta rel and a decrease in d-value with a concentration of added SDS.

Cellulose↗
PubMed1996

Acceptor specificity of cyclodextrin glucanotransferase from an alkalophilic Bacillus species and synthesis of glucosyl rhamnose.

Cyclodextrin glucanotransferase [1,4-alpha-D-glucan 4-alpha-D-(1,4-alpha-D-glucano)-transferase (cyclizing), EC 2. 4. 1. 19] from an alkalophilic Bacillus species A2-5a had a wider acceptor specificity than that from B. macerans, which was similar to those from B. stearothermophilus and B. circulans. Glucosyl rhamnose produced by the CGTase was identified as glucopyranosyl-alpha-1,4-rhamnopyranose by alpha- and beta-glucosidase treatments, and 1H- and 13C-NMR analyses.

Bacillus↗
PubMed1996

Experimental transmission of Babesia ovata oshimensis n. var. of cattle in Japan by Haemaphysalis longicornis.

Transovarial transmission of a newly isolated large intraerythrocytic parasite, Babesia sp. 1 by Haemaphysalis longicornis was experimentally demonstrated. Larvae of H. longicornis were transovarially infected with the parasite by feeding as adults on the calf which had been experimentally infected with B. sp. 1. Piroplasms of B. sp. 1 were observed in peripheral blood of the calf which was infested with the parasite-infected larvae. Based on the transmissibility of the parasite with vector ticks, this parasite was suggested to be a variety of B. ovata. Thus, we propose a new variety name for B. sp. 1 as B. ovata oshimensis n. var.

Animals↗
PubMed1996

Immunoglobulin as an eosinophil degranulation factor: change in immunoglobulin level in nasal lavage fluid after antigen challenge.

To examine the involvement of immunologlobulins in eosinophil degranulation, we investigated the change in the amount of immunogobulins in consecutive nasal lavage fluid samples obtained after antigen challenge, as compared with the corresponding eosinophil counts and eosinophil cationic protein (ECP) levels. Eosinophil counts and ECP levels increased both during the early and late phases but more markedly during the late phase. The levels of secretory IgA (sIgA) and IgA were prominently increased at 10 min after challenge, but returned to the respective prechallenge levels by 1 h after challenge. In the late phase they increased again. ECP levels were correlated both with cosinophil counts x sIgA levels and with eosinopil counts x IgA levels. Both sIgA/albumin and IgA/albumin ratios decreased in the early phase, due to the increased permeability of postcapillary vessels, but then increased again in the late phase becoming higher than the respective prechallenge levels. In the late phase, both secretory IgA and IgA seemed to be actively produced and released in nasal mucosa, thus causing eosinophil degranulation.

Adolescent↗
PubMed1996

[Inhaled nitric oxide for postoperative pulmonary hypertensive crisis in a patient with complete atrioventricular canal associated with Down's syndrome: a case report].

Two-year-old boy with Down's syndrome was treated with inhaled nitric oxide for pulmonary hypertensive crisis after correction of complete atrioventricular canal and persistent ductus arteriosus. The acute rise in pulmonary pressure and hemodynamic instability occurred on 3rd, 4th and 6th post operative days and pulmonary vasodilation with prostaglandin E1 and amrinone had failed. Twenty ppm of inhaled nitric oxide effectively reduced the pulmonary pressure and the patient was subsequently weaned from ventilation. Inhaled nitric oxide exerted a pulmonary vasodilation without decreasing systemic pressure in this patient with postoperative pulmonary hypertensive crisis.

Acute Disease↗
PubMed1996

[Successful repair of right atrial rupture due to nonpenetrating trauma of the chest].

A 24-year-old male was brought to our hospital after being injured in a traffic accident. On arrival, his blood pressure was 70/44 mmHg and his pulse rate was 135/min and regular. Chest X-p revealed cardiomegaly but there was no pleural effusion or bone fracture. Echocardiogram revealed cardiac tamponade and he was diagnosed as cardiac rupture due to non penetrating trauma. Under midline sternotomy, right atrial rupture was repaired. The patient developed cardiac arrest lasting approximately 8 minutes during anesthetic induction, so he needed to be ventilated for 8 days. However his postoperative course was not so eventful and he was discharged 38 days after surgery without any neurophysiological disturbance.

Accidents, Traffic↗
PubMed1996

[Management of postoperative pulmonary hypertensive crisis in children--indication and usefulness of inhaled nitric oxide therapy as a pulmonary vasodilator].

Among 176 pediatric patients who underwent open heart surgery from 1990 to 1996, 7 developed severe pulmonary hypertensive crisis (PHC) postoperatively. All patients were treated with conventional medical therapy consisting of hyperventilation and deep sedation. Prostaglandin E1 and/or amrinone were administered initially as a pulmonary vasodilator, and in 3 of the 7 patients this resulted in immediate improvement in hemodynamics. These patients subsequently weaned off ventilatory support and they were discharged from the hospital. In 4 other patients, pulmonary vasodilator therapy with prostaglandin E1 and amrinone had failed and they were treated with inhaled nitric oxide (NO). In all patients, inhalation of NO resulted in immediate decrease in pulmonary pressure without significant change in systemic arterial pressure. Two patients successfully weaned from the ventilator, whereas in 2 patients decrease in pulmonary pressure was transient. They developed airway bleeding and died as a result of respiratory insufficiency. Although inhaled NO effectively reduced pulmonary pressure in patients with PHC, this effect was not maintained over 12 hours in patients associated with bronchopulmonary dysplasia. In patients at risk for severe PHC, rapid treatment with NO inhalation after initial event as well as the prevention of lung injury caused by mechanical ventilation were found to be important in the postoperative management.

Administration, Inhalation↗
PubMed1996

[Anatomic correction of double-outlet right ventricle associated with hereditary spherocytosis--a case report].

A 3-year-old boy with hereditary spherocytosis (HS) underwent anatomical correction for double-outlet right ventricle. In addition to acute injury to the red blood cells during cardiopulmonary bypass, chronic mechanical trauma related to the presence of internal conduit and transannular patch must be considered in this patient with HS. We therefore performed splencetomy prior to cardiac surgery to prevent perioperative serious hemolysis. Preoperative examination showed the anatomy was considered suitable for REV procedure. The position of the aorta was anterior, VSD was classified as subpulmonic and associated with subvalvular stenosis. Under cardiopulmonary bypass, infundibular septum was resected and intraventricular tunnel was constructed. The pulmonary artery was transected at the level of the valve commissures and translocated onto the right ventricle without transection of aorta. Right ventricular outflow tract was reconstructed with a patch bearing monocusp. No serious complication due to hemolysis occurred perioperatively. Postoperative angiocardiography revealed no stenosis in both left and right ventricular outflow tract. The patient was discharged on the 57th postoperative day and is doing well.

Child, Preschool↗
PubMed1995

Kinetically trapped structure in the renaturation of reduced oxindolealanine 62 lysozyme.

The refolded products of reduced native lysozyme and reduced OX62 lysozyme, in which Trp62 is converted to oxindolealanine (OX62) during the renaturation of sulfhydryl-disulfide interchange reactions at pH 8 and 37 degrees C, were investigated. On gel-chromatography eluted with 10% aqueous acetic acid containing 4 M urea, two peaks appeared in the refolded product of reduced OX62 lysozyme while a single peak appeared in the refolded product of reduced native lysozyme. From the analyses of the activity and primary and the tertiary structures of the derivative, the structure of the derivative from reduced native lysozyme was confirmed to be identical to that of the untreated one. On the other hand, the refolded product from reduced OX62 lysozyme had the same primary structure but a different tertiary structure compared to the untreated one. The tertiary structure of the refolded product from the reduced OX62 lysozyme was changed to that of the untreated one by the denaturation-renaturation treatment under nonreduced conditions. However, the refolded species was barely changed to that of the untreated one by incubation under physiological conditions. Therefore, the refolded product from reduced OX62 lysozyme was suggested to be a metastable and kinetically trapped product in the renaturation process of reduced OX62 lysozyme. In addition, an interaction involving the folding process of reduced lysozyme was discussed on the basis of the NMR analyses of the metastable structure.

Amino Acid Sequence↗
PubMed1995

Requirement for tyrosine phosphorylation of Cdk4 in G1 arrest induced by ultraviolet irradiation.

Exposure to ultraviolet light arrests the function of mammalian fibroblasts in the G1 phase of the cell cycle, as well as the S and G2 phases. Although p21, an inhibitor of cyclin-dependent kinase (Cdk) that is induced by DNA damage may partly account for the arrest in G1 (ref. 1), the mechanism is little understood. Here we show that tyrosine phosphorylation of Cdk4 is required for this arrest. In rat fibroblast, Cdk4 is tyrosine-phosphorylated during G1 progression, and its dephosphorylation is required for S phase. When cells are ultraviolet-irradiated, their arrest in G1 is accompanied by an increase in phosphorylation level. Conversely, cells expressing unphosphorylatable Cdk4F17 fail to arrest in G1, and suffer significantly elevated chromosomal aberrations and cell death.

Animals↗
PubMed1995

cAMP-dependent phosphorylation stimulates water permeability of aquaporin-collecting duct water channel protein expressed in Xenopus oocytes.

Among water channel proteins (aquaporins), aquaporin-collecting duct (AQP-CD) is the vasopressin-regulated water channel. Vasopressin causes cAMP production in the renal collecting duct cells, and this is believed to lead to exocytic insertion of water channel into the apical membrane (shuttle hypothesis). AQP-CD contains a consensus sequence for cAMP-dependent protein kinase, residues at positions 253-256 (Arg-Arg-Gln-Ser). To determine the role of this site, Ser-256 was substituted for Ala, Leu, Thr, Asp, or Glu by site-directed mutagenesis. In Xenopus oocytes injected with wild-type or mutated AQP-CD cRNAs, osmotic water permeability (Pf) was 4.8-7.7 times higher than Pf of water-injected oocytes. Incubation with cAMP plus forskolin or direct cAMP injection into the oocytes increased Pf of wild-type, but not mutated, AQP-CD-expressing oocytes, whereas the amounts of AQP-CD expression were similar in wild and mutated types as identified by Western blot analysis. In vitro phosphorylation studies of AQP-CD proteins expressed in oocyte showed that cAMP-dependent protein kinase phosphorylated wild-type, but not mutated, AQP-CD proteins. Phosphoamino acid analysis revealed that this phosphorylation occurred at the serine residue. Moreover, phosphorylation of AQP-CD protein in intact rat kidney medulla tissues was stimulated by incubation with cAMP. Our data suggest that cAMP stimulates water permeability of AQP-CD by phosphorylation. This process may contribute to the vasopressin-regulated water permeability of collecting duct in addition to the apical insertion of AQP-CD by exocytosis.

Animals↗