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Biomedical subjects

T Okuda

Publications and source records attributed to T Okuda.

At least 343 records · Page 19Linked to original sources
PubMed1989

Effect of rice fiber on human fecal microflora.

The effects of brown rice, containing fourfold as much dietary fiber as polished rice, on the human fecal microflora were determined. Significantly increased numbers of Bifidobacterium adolescentis and Enterococcus faecalis were observed during the brown rice intake, whereas the total counts and the numbers of bacteroides, Eubacterium aerofaciens, and Escherichia coli during the intake were lower than those before and after the intake. Lower numbers of clostridia and low incidences of Clostridium paraputrificum and C. perfringens were observed during the brown rice intake.

Adult↗
PubMed1989

Inhibitory effect of (-)-epigallocatechin gallate on carcinogenesis with N-ethyl-N'-nitro-N-nitrosoguanidine in mouse duodenum.

(-)-Epigallocatechin gallate (EGCG) is the main polyphenolic constituent of green tea infusion and inhibits tumor promotion by teleocidin in two-stage carcinogenesis on mouse skin. In this work, EGCG was found to inhibit tumor promotion in the gastrointestinal tract in a model system of mouse duodenal carcinogenesis with N-ethyl-N'-nitro-N-nitrosoguanidine. The duodenal tumors that developed were studied stereomicroscopically and histologically.

Animals↗
PubMed1989

Ambient C1- ions modify rat mesangial cell contraction by modulating cell inositol trisphosphate and Ca2+ via enhanced prostaglandin E2.

Our recent observation showed that angiotensin II (AII) and arginine vasopressin (AVP) stimulate Ca2+-activated Cl- conductance in mesangial cells. These data raise the possibility that mesangial cell function may be modulated by extracellular chloride concentration [( Cl-]o). The present study was undertaken to test this possibility using cultured rat mesangial cells. When the [Cl-]o was reduced to zero, the percentage of mesangial cells showing contraction responding to AII and AVP was decreased from 72 +/- 9 to 33 +/- 10% and from 60 +/- 4 to 24 +/- 11%, respectively. Ca2+ transients induced by AII and AVP, measured in mesangial cells loaded with Ca2+-sensitive photoprotein aequorin, were attenuated as [Cl-]o decreased. Also, when [Cl-]o decreased, inositol trisphosphate (IP3) levels of mesangial cells were suppressed, both in the presence and absence of AII or AVP. PGE2 production by mesangial cells increased when [Cl-]o decreased and the effects of ambient Cl- deprivation could be restored by addition of indomethacin to the Cl- -free medium. Moreover, PGE2 decreased mesangial cell contractility, Ca2+ transients, and IP3 production in response to AII and AVP. These data suggest that the decrease in [Cl-]o attenuates mesangial cell contraction by suppressing IP3 production and thus Ca2+ transients in response to AII and AVP through enhanced PGE2 production.

Angiotensin II↗
PubMed1989

Binding of hydrochlorothiazide to erythrocytes.

Hydrochlorothiazide (HCT) was administered orally to healthy volunteers and intravenously to rabbits. HCT concentrations in plasma (Cp) and erythrocytes (Ce) were determined by a high-performance liquid chromatographic method. Ce was about 9-fold that of Cp 24 h after the administration to volunteers, and 8-fold 6 h after the administration to rabbits. From the results of the in vitro binding study which was done with rabbit erythrocytes, at least the presence of three kinds of binding site for HCT was expected. The first binding site was characterized by extremely high affinity and very low capacity, and was unaffected by acetazolamide, known as a carbonic anhydrase inhibitor. The second one was characterized by medium affinity and medium capacity, and disappeared under the presence of acetazolamide and may be due to the carbonic anhydrase of erythrocytes. The third one was characterized by low affinity, but its binding capacity was extremely high and apparently unsaturable in the HCT concentration range studied (0.5-100 micrograms/ml = 1.68-336 microM). The binding of HCT to erythrocytes seems to be dominated by the second binding site in the therapeutic range (under 1 microgram/ml of plasma).

Adult↗
PubMed1989

Tannins of cornaceous plants. I. Cornusiins A, B and C, dimeric monomeric and trimeric hydrolyzable tannins from Cornus officinalis, and orientation of valoneoyl group in related tannins.

Cornusiin A (1), cornusiin B (2) and cornusiin C (3), new dimeric, monomeric and trimeric hydrolyzable tannins, were isolated from the fruits of Cornus officinalis (Cornaceae). Their structures, including the orientation of the valoneoyl group in 1 and 3, were established on the basis of chemical and spectroscopic data. 2,3-Di-O-galloyl-D-glucose (7), 1,2,3-tri-O-galloyl-beta-D-glucose, 1,2,6-tri-O-galloyl-beta-D-glucose, 1,2,3,6-tetra-O-galloyl-beta-D-glucose, gemin D (5), isoterchebin, tellimagrandin I (6) and tellimagrandin II were also isolated from the fruits. The orientation of the valoneoyl group in camptothin A (14) and that in camptothin B (15), which had been isolated from Camptotheca acuminata (Nyssaceae), were also determined based on that in 1.

Antineoplastic Agents, Phytogenic↗
PubMed1989

Phenolic constituents of licorice. II. Structures of licopyranocoumarin, licoarylcoumarin and glisoflavone, and inhibitory effects of licorice phenolics on xanthine oxidase.

An anti-HIV (human immunodeficiency virus) phenolic constituent, licopyranocoumarin (4), and two other new phenolics named licoarylcoumarin (5) and glisoflavone (6) were isolated from Si-pei licorice (a commercial licorice; root and stolon of Glycyrrhiza sp. from the north-western region of China) using droplet countercurrent chromatography and centrifugal partition chromatography, and their structures were assigned based on chemical and spectroscopic data. Kaempferol 3-O-methyl ether (7) and licocoumarone (8) were also isolated from the licorice. The inhibitory effects of ten licorice phenolics on xanthine oxidase were examined. Licochalcone B (1), glycyrrhisoflavone (2), 8 and licochalcone A (19) showed 50% inhibition at the concentration of 1.3-5.6 x 10(-5) M.

Coumarins↗
PubMed1989

Camelliin B and nobotanin I, macrocyclic ellagitannin dimers and related dimers, and their antitumor activity.

Camelliin B and nobotanin I, dimeric hydrolyzable tannins of a new class having macrocyclic structures, were isolated from Camellia japonica and Heterocentron roseum, respectively. Nobotanin G and H of the structures related to nobotanin I, were also obtained from H. roseum. Camelliin B and also woodfordin C, a macrocyclic dimer from Woodfordia fruticosa, exhibited marked host-mediated antitumor activities.

Animals↗
PubMed1989

[Effects of antiinflammatory agents on rat paw tuberculin response].

A marked tuberculin response as well as carrageenin edema were induced in rat hind paw to compare the effects of antiinflammatory agents on these responses. Non-steroidal antiinflammatory agents such as diclofenac and piroxicam were very weak inhibitors of the paw tuberculin response. These agents showed only a slight inhibitory effect on tuberculin response even at doses that were four to five times larger than the 50% effective doses for inhibiting carrageenin edema. On the other hand, steroidal antiinflammatory agents, dexamethasone and prednisolone, showed potent inhibitory effects on the paw tuberculin response at the 50% effective doses for inhibiting carrageenin edema. The above findings clearly revealed the difference in characters between non-steroids and steroids by comparing their effects on tuberculin response and carrageenin edema. The different properties of two classes of antiinflammatory drugs may be of significance in evaluating the effect of antiinflammatory agents on delayed-type hypersensitivity.

Animals↗
PubMed1989

Effect of TRK-100, a prostacyclin analogue, on endotoxin-induced enhancement of blood coagulation in rats.

TRK-100 (0.03, 0.1 and 0.3 mg/kg, p.o.), a chemically stable analogue of prostacyclin, dose-dependently prevented blood coagulation and glomerular fibrin deposition which were enhanced by 4 hr infusion of endotoxin (100 mg/kg) in rats. In addition, TRK-100 suppressed the generation of endotoxin-induced tissue thromboplastin like activity in cultured human endothelial cells.

Administration, Oral↗
PubMed1989

Penicillin G-induced cutaneous anaphylaxis in the guinea pig.

Allergic cutaneous responses were induced by intradermal injection of penicillin G (PCG) and PCG-bovine serum albumin (BSA) conjugates onto the back of guinea pig actively immunized with PCG potassium (25 mg/animal) incorporated in Freund's complete adjuvant. The PCG-induced response was characterized macroscopically by erythema and edema with a maximum level at 24 hrs after elicitation and microscopically by the infiltration with basophils, macrophages and lymphocytes following with neutrophils. In addition, intensity of macrophage-infiltration shared a similar time course change with those of erythema and edema. These suggest that this response is associated to a delayed type hypersensitivity of Jones-Mote type. On the other hand, in the PCG-BSA-induced response the edema with erythema at the early phase was a noticeable observation and this response disappeared within 12 hrs, although the erythema continued by 24 hrs. Microscopically, the degranulation of mast cells and severe infiltration with neutrophils in the early phase and the infiltration of eosinophils in the late phase accompanying the infiltration with monocytes, basophils and lymphocytes were characteristic findings, which suggest that PCG-BSA response is a similar hypersensitivity to an atopic dermatitis. As mentioned above, we confirmed two types of allergic cutaneous responses in the guinea pig immunized with PCG.

Animals↗
PubMed1989

[Relationships between tooth loss and electromyographic activities of masticatory muscles].

For purpose of evaluating the characteristic of electromyographic activities of masticatory muscles with front or molar tooth loss, electromyographic activities of masticatory muscles and mandibular movements during tooth tapping and gum chewing were investigated in each group of tooth loss, and were compared with those of control group. The results were as follows. 1. In reference to the group with front tooth loss, 1) On tooth tapping, each S.D. of the time parameters of electromyographic activities of jaw closing muscles especially masseter and posterior temporalis was small, and that of jaw opening muscle was large. 2) On gum chewing, offset of jaw closing muscles' activities especially masseter and anterior temporalis were delayed. 3) On both tooth tapping and gum chewing, there was no difference in mandibular movements from control group. 2. In reference to the group with molar tooth loss, 1) On both tooth tapping and gum chewing, each S.D. of the time parameters of electromyographic activities of jaw closing muscles was large. 2) On tooth tapping, S.D. of opening ratio was large. 3) On gum chewing, both S.D. of chewing cycle and opening ratio were large.

Electromyography↗
PubMed1989

[Electromyographic study on the effects of head position to head and neck muscles].

The purpose of this study is to reveal the relationship between the head position, and the neck and head muscles. At 4 head positions, the activities of masseter, anterior temporal, anterior digastric, sternocleidomastoid and trapezius muscle of ten normal subjects standing straight were investigated electromyographically with surface electrodes during voluntary maximal clenching in centric occlusion. Head positions were right tilting, left tilting, up-right and natural head position. The results obtained were as follows; 1. During head tilting, the activities of anterior digastric and sternocleidomastoid muscle on the tilting side were increased, the activities of masseter and trapezius muscle on the opposite side of the tilting side were increased, the activity of the anterior temporal muscle did not vary from the activity during up-right head position. 2. During natural head position, only the activity of sternocleidomastoid muscle on the natural tilting side was increased.

Electromyography↗
PubMed1989

[Electromyographic study on lateral jaw movements].

This study aims to analyse how jaw-closing muscle activities are modulated during lateral jaw movement. Jaw movements were recorded by Sirognathograph (Siemens Co.) and electromyograms were simultaneously recorded from bilateral masseter, anterior temporal and posterior temporal muscles in 20 young adults without any stomatognathic dysfunction. Each subject sat upright in the chair with the head unsupported. The lateral jaw movements from the intercuspal position were guided three times for each lateral excurtion (right and left). The data were recorded on magnetic tape and later analysed by use of a computer. Following variables were analysed; the number of contacted teeth, the position of contacted teeth, the muscle activities during lateral jaw movement. The results can be summarised as follows; 1) The working-side posterior temporal muscle showed obvious activity in more than 90% subjects during lateral jaw movement. However, this muscle activity was not influence by the number or position of the contacted teeth. 2) The right side masseter muscle tended to show the obvious activity during both right and left lateral jaw movement. The results of this study suggest the difference in the activities between masseter and temporal muscle during lateral jaw movement.

Dental Occlusion↗
PubMed1989

[Impaired B lymphocyte function during open heart surgery].

Sequential in vitro lymphocyte function tests in 13 patients undergoing cardiac operation were performed to study B lymphocyte function following operation. Lymphocytes were stimulated with phytohemagglutinin (PHA), pokeweed mitogen (PWM) and Staphylococcus aureus Cowan 1 (SAC). Mitogen responses were measured by 3H-labeled thymidine incorporation. The SAC responses were significantly depressed following operation. Immunoglobulin secreting cells were measured by protein A plaque forming cell assay. The numbers of immunoglobulin secreting cells induced by PWM or SAC decreased remarkably at least as long as 3 day after the operation. The percentage of circulating B lymphocytes increased significantly postoperatively. This indicates that the B lymphocytes remaining after the operation were functionally impaired.

Antibody-Producing Cells↗
PubMed1989

[Spontaneous remission of four months' duration in hypoplastic leukemia with tetraploid chromosome after blood transfusions and infection].

Spontaneous complete remission of four months' duration was observed in a 51-year-old male with hypoplastic leukemia. Cytogenetical analysis revealed that leukemia cells of this patient were tetraploid. The diameter of leukemia cells involving myeloid cells ranged from 30 to 50 mu. The remission was apparently associated with repeated blood transfusions and severe infection. Complete remission was confirmed by normal morphology and karyotype of the bone marrow cells, although in vitro marrow stem cell growth did not return to normal. Thus, normal hematopoiesis may not have recovered when the diagnosis of spontaneous remission was made.

Aneuploidy↗
PubMed1989

Heterogeneous features of Ph-negative CML--possible existence of Ph-negative, bcr-rearrangement-negative CML.

We have examined eight patients with Ph-negative chronic myelocytic leukemia (CML). Two of the patients had the same molecular abnormalities as well as the same clinical and hematological features as those of Ph-positive CML. The other six patients showed no genomic rearrangement. This group was hematologically divided into four subgroups, namely chronic myelomonocytic leukemia, undifferentiated chronic myeloproliferative disorder, chronic neutrophilic leukemia and CML-like syndrome. This last subgroup resembled Ph-positive CML in many points except for rather moderate proliferation of granulocyte lineage, and it was difficult to clinically separate it from Ph-positive CML.

Adult↗
PubMed1989

Studies on T-cell colony formation in chronic renal failure (CRF) patients.

In order to study the possibility of abnormal differentiation and proliferation of T-cell precursors in chronic renal failure (CRF), we studied T-cell colony formation in CRF patients. The two-step monolayer method, with phytohemagglutinin-P as the inducer, was used for T-cell colony formation. In our results, colony formation was markedly reduced in CRF patients in comparison with normal controls, with about half of the former showing no colony growth. All cases showed a significant increase in colony numbers with in vitro plasmapheresis (the replacement of autologous plasma in the culture system with normal AB plasma). A significant increase in colony numbers was also seen with the addition of exogenous interleukin-2 (IL-2). The addition of IL-2 in the presence of normal plasma, in particular, induced an increase in colony numbers to near the levels in normal subjects. These results suggest that T-cell precursors exist in near normal numbers in CRF patients and that there are uremic inhibitors in the plasma. A reduced production of IL-2 is also indicated. These factors may be involved in the pathogenesis of immunodeficiency in CRF patients.

Adult↗