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Biomedical subjects

S Takagi

Publications and source records attributed to S Takagi.

At least 307 records · Page 17Linked to original sources
PubMed1994

Physical and chemical properties of resin-reinforced calcium phosphate cements.

OBJECTIVES: The purpose of this study was to improve the handling and physical properties of a self-setting, water-based calcium phosphate cement by combining it with polymerizable resins and to study the setting reactions involved. METHODS: Dual-cured composite cements were prepared from a calcium phosphate cement powder and dental monomers that contain carboxylated hydrophilic resins or resin/water mixtures. The setting reaction of the calcium phosphate cement in the presence of the resins was evaluated by pH measurements, infrared spectroscopy, diametral tensile strength, x-ray diffraction analysis, and scanning electron microscopy. RESULTS: Carboxylated resins were chosen because they can form ionic bonds to the mineral filler, which was confirmed by appearance of an infrared absorbance peak at 1552 cm-1 within 24 h after mixing due to the formation of a carboxylate salt. Hydroxyapatite did not develop in composites prepared from resin and calcium phosphate cement. However, composites from calcium phosphate cement, resin and water showed approximately 40% hydroxyapatite. The resulting composite cements have moderately high DTS of 14-15 MPa and high pH. SIGNIFICANCE: Hydrophilic acidic resins allows mixing with water and/or allow rapid diffusion of water into the resinous cement so that the dissolution and reprecipitation processes required for the conversion of the calcium phosphate components to hydroxyapatite can occur. The characteristics of the resulting composite cements suggest that the materials may be useful in pulp capping and/or cavity lining.

Calcium Phosphates↗
PubMed1994

Effect of trimebutine maleate on the contractile response of the isolated ileum from diabetic rats.

1. Tension of the isolated ileum from diabetic rats induced by streptozotocin was measured isometrically to study the mode of action of trimebutine maleate (TMB). 2. The hyperreactivity of contractile response to KCl was observed in the isolated ileum from diabetic rats. TMB inhibited the contraction induced by KCl and acetylcholine (ACh) in normal solution. 3. In Ca2+ free solution, the hyperreactivity of contractile response to KCl was attenuated, and TMB did not inhibit the contraction induced by KCl. In contrast, TMB inhibited the contraction induced by ACh even in Ca2+ free solution. 4. These results suggest that the hyperreactivity of contractile response to KCl in the ileum from diabetic rats is due to the enhancement of Ca2+ influx through voltage-dependent Ca2+ channel and that TMB inhibits the hyperreactivity of contractile response through the inhibition of Ca2+ movement by the cell.

Animals↗
PubMed1994

Comparative effects of loperamide hydrochloride on prostaglandin E1-induced contraction in isolated fundus and ileum of guinea pigs.

The tension of isolated preparations of the fundus and the ileum of guinea pigs was measured isometrically to study the specific effect of loperamide hydrochloride on prostaglandin E1-induced contraction. Prostaglandin E1 caused concentration-dependent contraction in both the fundus and the ileum, and there was no significant difference between the fundus and the ileum. Loperamide hydrochloride inhibited prostaglandin E1-induced contraction in the fundus and the ileum. From the pD'2 value, loperamide hydrochloride caused greater inhibition of the contraction in the ileum than in the fundus. In a Ca(2+)-free solution containing 0.1 mM EGTA, prostaglandin E1-induced contraction in the ileum was almost eliminated, whereas 58% of the contraction in the fundus still remained. In Ca(2+)-free solution, loperamide hydrochloride and verapamil hydrochloride had no influence on prostaglandin E1-induced contraction, but markedly inhibited Ca(2+)-induced contraction. These results suggest that loperamide hydrochloride shows regional differences between gastrointestinal smooth muscles contracted by prostaglandin E1, and this may reflect one of the mechanisms in its antidiarrheal action through the suppression of peristalsis.

Alprostadil↗
PubMed1994

Anti-human IgE monoclonal antibodies recognizing epitopes related to the binding sites of high and low affinity IgE receptors.

Anti-human IgE monoclonal antibodies (mAbs) were produced and eight clones recognizing epitopes on native IgE were selected. Epitopes were mapped by a competitive inhibition enzyme-linked immunosorbent assay, Western blotting and a multi-pin peptide technology. Four sites (one each in the C epsilon 1, C epsilon 2, C epsilon 2/C epsilon 3 junction and C epsilon 3) were recognized by the mAbs. The relationship between the four epitopes and the binding sites of high and low affinity IgE receptors (Fc epsilon RI and Fc epsilon RII, respectively) was studied using a monovalent Fab fragment of each mAb as a binding inhibitor. The IgE-Fc epsilon RII binding was clearly inhibited by the mAb recognizing the C epsilon 2/C epsilon 3 junction, suggesting that Fc epsilon RII binds to a rather limited area around the C epsilon 2/C epsilon 3 junction. The IgE-Fc epsilon RI binding, on the other hand, was scarcely inhibited by any single mAb. However, the binding was inhibited when the epitope in C epsilon 2 was blocked simultaneously with that at the C epsilon 2/C epsilon 3 junction or with that in C epsilon 3, indicating that these three distinct epitopes are related to the Fc epsilon RI binding sites. When these three epitopes were shown in the stereograph of human IgE, the Fc epsilon RI binding area was spread largely on the groove side between C epsilon 2 and C epsilon 3 domains. These results suggest that Fc epsilon RI acquires the high affinity through multiple bindings.

Amino Acid Sequence↗
PubMed1994

Fimbria-specific immune response in various inbred mice inoculated with Porphyromonas gingivalis 381.

We studied the genetic control of Porphyromonas gingivalis fimbriae response. Inbred mice with different H-2 haplotypes and/or different genetic backgrounds were inoculated with viable P. gingivalis 381 cells and tested for fimbria-specific T cell responses in vivo (delayed-type hypersensitivity). H-2d mice showed a strong footpad response, whereas H-2b mice showed a weak response to fimbriae from P. gingivalis. Similar evidence of genetic control was obtained with an enzyme-linked immunosorbent assay for the detection of IgG antibody in inbred mice (BALB/c, C3H/HeN and C57BL/6). Several immunoglobulin G (IgG) subclass responses were associated with H-2 in these B10 congenic mice. However, quantification of IgG antibody to fimbriae was not controlled by H-2 in B10 congenic mice. The results indicate that, in mice, the responsiveness to fimbriae of P. gingivalis can be controlled by several genes, including the H-2 complex. C3H/HeN mice were inoculated with the fimbriae intravenously, and the expression of surface antigens on spleen T cells was measured in a fluorescent antibody cell sorter. Stimulation by fimbriae resulted in a changed expression of surface antigens on T cells. Thus, the fimbriae can induce T cell activation.

Animals↗
PubMed1994

Differences of LAK-activity and IL-2 responsiveness between alpha/beta and gamma/delta T cells which developed after thymus transplantation.

A patient with severe combined immunodeficiency was transplanted with T cell depleted haploidentical bone marrow from his father and was later given a thymic graft from an unrelated donor. alpha/beta and gamma/delta T cells of bone marrow donor origin appeared only after the thymus transplantation procedure. Among the peripheral blood lymphocytes (PBL), gamma/delta T cells comprised 10-20% and most of them were delta TCS1+. The alpha/beta T cells were single positive cells, either CD4+ or CD8+. Expression of CD5, CD7 and CD8 alpha,beta molecules on alpha/beta T cells was reduced. Functional studies showed that gamma/delta T cells proliferated slightly in response to anti-CD3 stimulation, and proliferated well with exogenous IL-2 stimulation, while alpha/beta T cells did not proliferate following mitogenic stimulation even in the presence of IL-2. gamma/delta T cells but not alpha/beta T cells exhibited some LAK activity after culturing with IL-2. Since alpha/beta T cells expressed IL-2R alpha and beta chains after mitogenic stimulation and bound IL-2, the deficit(s) in these cells was considered to occur after IL-2 binding to the IL-2R. These results indicate thymic dependency of both types of T cells and that two types of T cells differed in the acquisition of IL-2 responsiveness during development.

Bone Marrow Transplantation↗
PubMed1994

Effects on whole saliva of chewing gums containing calcium phosphates.

To evaluate chewing gums as a vehicle to increase salivary mineral saturation levels and enhance salivation, monocalcium phosphate monohydrate (MCPM) and an equimolar mixture of tetracalcium phosphate (TTCP) with dicalcium phosphate anhydrous (DCPA) were chosen as experimental chewing gum additives. Each of eight subjects chewed a commercial sugarless bubble gum (control) for 16 min or the same gum to which 5 wt% of MCPM or the TTCP-DCPM mixture had been added. The saliva samples collected every 2 min were analyzed for weight, pH, and total calcium (Ca) and phosphate (P) concentrations. Both experimental gums were found to increase significantly the Ca and P concentrations of saliva during the 16-minute period even more than with a previously evaluated gum that contained dicalcium phosphate dihydrate. The degree of saturation of tooth mineral was significantly increased by both experimental gums, with the greater increase being produced by the TTCP-DCPA gum. The MCPM gum produced a significantly greater saliva flow and a lower salivary pH than did the control and TTCP-DCPA gums. The results suggest that the experimental gums may be useful for promoting remineralization in general and for inducing salivation in xerostomic patients.

Adult↗
PubMed1994

Intravascular malignant lymphomatosis manifesting clinically as bilateral sudden hearing loss and cytomegalovirus encephalitis.

A 49-year-old man developed bilateral sudden hearing loss followed by cerebral infarction and cytomegalovirus (CMV) encephalitis. Autopsy confirmed intravascular malignant lymphomatosis (IML). A literature review indicates that hearing loss can be the initial manifestation of IML and also that CMV infection is more than an opportunistic infection and may participate in the cognitive manifestations in IML.

Cytomegalovirus Infections↗
PubMed1994

[Acidified aspirin-induced gastric lesion in rats with hepatic cirrhosis produced by N-nitrosodiethylamine or carbon tetrachloride. Effect of aldioxa on gastric lesions].

Gastric lesion was induced by the oral administration of acidified aspirin in rats with hepatic cirrhosis produced by N-nitrosodiethylamine (NDA) or carbon tetrachloride (CCl4). Gastric lesion by acidified aspirin was aggravated in NDA-induced cirrhosis, but not in CCl4-cirrhotic rats. To clarify this difference in the susceptibility of the gastric mucosa, gastric mucosal blood flow and gastric emptying were measured by the hydrogen gas clearance method and beads method, respectively. Gastric mucosal blood flow was lower and gastric emptying was significantly delayed in NDA-induced cirrhotic rats as compared with the controls, but not in CCl4-induced cirrhotic rats. Gastric mucosal blood flow in NDA-induced cirrhotic rats was significantly decreased by the oral administration of acidified aspirin as compared with the controls. Aldioxa dose-dependently inhibited the gastric lesion formation by acidified aspirin and inhibited the decrease of gastric mucosal blood flow in NDA-induced cirrhotic rats. These results suggest that aggravation of gastric lesion induced by acidified aspirin in NDA-induced cirrhotic rats would be due to the decrease of gastric mucosal blood flow and delay of gastric emptying. In addition, aldioxa showed a protective effect against gastric lesions induced by acidified aspirin in NDA-induced cirrhotic rats, suggesting that this compound would have an inhibitory effect on gastric lesions that are accompanied by hepatic cirrhosis.

Allantoin↗
PubMed1994

Mutation of the p53 gene in gallbladder cancer.

Genetic alteration of the p53 gene was examined in tissue specimens of primary gallbladder cancer (GBC) using PCR-single strand conformation polymorphism (SSCP) and direct sequencing analyses. The p53 gene mutation was detected in five of the 16 GBC cases examined (31%). All five cases showed single point mutations; four were mutations resulting in amino acid substitution and the other was one base-pair deletion. Of the five mutations detected, four occurred at evolutionarily conserved regions and the remaining one at a well conserved region among species. Our result is similar to those of previous reports for various human cancers in mutation scattering over four of the five conserved domains.

Adult↗
PubMed1994

Effects of dietary supplementation with lactosucrose (4G-beta-D-galactosylsucrose) on cecal flora, cecal metabolites, and performance in broiler chickens.

The effects of dietary lactosucrose on cecal flora, cecal metabolites, and performance were studied in eight 20-d-old and eight 62-d-old broiler chickens fed a basal diet (control) or a diet with .15% lactosucrose added. On Day 20 of age, the frequency of occurrence of lecithinase-negative clostridia were decreased (P < .05) by lactosucrose consumption. On Day 62 of age, the numbers of bifidobacteria were increased (P < .05) by lactosucrose consumption, but the counts of lecithinase-positive clostridia, including Clostridium perfringens, bacteriodaceae, and staphylococci, total anaerobic bacteria, and the frequency of occurrence of pseudomonads were decreased (P < .05). No detectable change was observed in counts of other organisms throughout the experimental period. Cecal concentration of ammonia (P < .01), phenol (P < .05), and cresol (P < .05) were decreased on Day 62 of lactosucrose consumption. Acetic acid and butyric acid were increased (P < .01 and P < .05, respectively) on Day 62 of lactosucrose consumption. Environmental ammonia and odor of chicken ceca were greatly reduced by lactosucrose consumption.

Ammonia↗
PubMed1994

Telescience testbed experiments of intracellular recordings in the Xenopus oocyte.

The feasibility of intracellular recordings under constraints for experimental conditions in outer space were tested at a telescience testbed of the National Space Development Agency of Japan. We attempted to study the dose-response relationship of adenosine-induced potential changes in the Xenopus oocyte. The testbed simulated the distance from a ground control room to oocytes in an orbital laboratory; signals were delayed and compressed from one "station" to other. A microelectrode was inserted into the oocyte using remote control on the manipulator and on the xyz-planes of the platform with stereoscopic pictures observed through a head mounted display. When the transfer rate of the visual signals was decreased from 1.5 Mbps to 128 Kbps, insertion of the electrode became almost impossible because of reduced picture quality. Once the electrode was inserted, however, dose-dependent adenosine responses could be observed with little trouble.

Adenosine↗
PubMed1994

Pyogenic psoas muscle abscess: report of three cases.

We report three cases of primary psoas muscle abscess. Two of these cases were treated by open drainage through a lumbar incision and the other was by ultrasonography (USG)-guided percutaneous aspiration of the abscess. Antibiotic therapy was also instituted in all cases. Post-operatively, the patients recovered well with no sign of recurrence. USG-guided percutaneous drainage combined with appropriate antibiotic therapy appears to be the first choice procedure for treatment of the primary psoas abscess if correct diagnosis is promptly made and the procedure can be performed.

Adult↗
PubMed1994

[Clinical and immunological analysis of Birch pollenosis].

In recent years, the number of cases Birch pollenosis has increased, but there have been very few reports, and therefore we decided to carry on this clinical and immunological analysis as follows. (1) Statistical analysis of Birch pollenosis patients who visited the Department of Otorhinolaryngology of Hokkaido University School of Medicine, Sapporo. (2) Study of atmospheric birch pollen counts and investigation of the relationship between the incidence of pollenosis and pollen count. (3) Allergen analysis of Japanese Birch pollen using Western blotting method. (1) From 1990 to 1992, 392 cases of nasal allergy visited our hospital and 74 cases (18.9% of all cases) were birch pollenosis. There was a significant increase in the number of cases birch pollenosis, compared with previous reports. (2) Atmospheric pollen grains of birch pollen were collected by Durham's pollen trap at Hokkaido University School of Medicine, Sapporo from 1990 to 1992. In this study, birch pollen was collected from the beginning of April to the middle of June. The first day when birch pollen was collected in this study was about one month earlier than previously reported. We suspected that the mean temperature rise of Sapporo city in April is one of the factors that lead to the increase of incidence of birch pollenosis. (3) Allergens in birch pollens from Betula platyphylla Sukatchev var. japonica and Betula Ermanii Cham in Japan were identified by Western blotting, following separation by SDS-PAGE, transfer to PVDF membranes and incubation with sera from 35 birch pollenosis patients. In almost all cases, 17kd molecular from B. platyphylla and B. Ermanii pollen proteins were detected as the major IgE binding components.

Adolescent↗
PubMed1994

[Two cases of distal superior cerebellar artery aneurysm].

Two cases of subarachnoid hemorrhage due to a ruptured aneurysm of the distal superior cerebellar artery (SCA) are reported. In the first case the patient was a 78-year-old woman who complained of severe headaches and was admitted to a local hospital on May 25, 1992. A CT scan revealed a subarachnoid hemorrhage, and an angiogram showed an aneurysm of the right ambient segment of the superior cerebellar artery. Trapping of the aneurysm was successfully performed via a subtemporal approach on June 9, 1992. In the second case the patient was a 46-year-old man who complained of severe headaches and was admitted to Kurume University Hospital. A CT scan showed subarachnoid hemorrhage and an angiogram showed an aneurysm of the right ambient segment of superior cerebellar artery. Trapping of the aneurysm was successfully performed via a subtemporal approach on Sept 11, 1990. Forty-three reported cases of distal SCA aneurysm were reviewed. Only one patient received early surgical treatment, and with surgery in all of the other cases being delayed. Both of our patients underwent delayed surgical treatment with excellent results. The clinical characteristics of distal SCA aneurysms and the timing of surgery are discussed.

Aged↗
PubMed1994

[Empiric therapy with fluconazole in granulocytopenic patients with carcinoma or leukemia].

We performed a randomized clinical trial in granulocytopenic patients with carcinoma or leukemia. Patients with persistent fever for more than 2 days despite antibiotic therapy were randomized to antibiotic plus fluconazole therapy group (FLCZ group) or antibiotic therapy only group (antibiotic group) by the envelope method. It was possible to evaluate clinical efficacies in 62 patients (37 patients in FLCZ group and 25 patients in antibiotics group). In patients whose neutrophil counts were less than 100/microliters on the initial day of therapy, clinical efficacy rates were 72.0% (18/25) in FLCZ group and 57.1% (8/14) in antibiotics group. In patients whose neutrophil counts continued to be less than 100/microliters during therapy, clinical efficacy rates were 64.3% (9/14) and 50.0% (3/6), respectively. Further, in patients whose neutrophil counts continued to be less than 500/microliters during therapy, they were 76.9% (20/26) and 53.3% (8/15), respectively. No severe side effects nor severe case of abnormal change in laboratory test values due to fluconazole were observed in this trial. These data suggest that empiric antifungal therapy with fluconazole is effective for fungal infections in granulocytopenic patients with carcinoma and leukemia.

Adult↗
PubMed1994

Time-course of lens opacity and morphological changes in rabbit lens epithelial cells after intravitreal silicone oil injection.

The clinical course of lens opacity and the morphological changes in lens epithelial cells after intravitreal silicone oil injection were observed for 3 months in 21 normal adult albino rabbits. After the simple vitrectomy in both eyes of each rabbit, silicone oil was injected into the vitreous in one eye and the other eye was kept as the control. By photoslit-lamp microscopy, 8 of the 14 examined eyes showed early posterior subcapsular lens opacity one month after silicone oil injection. By transmission electron microscopy, intracellular vesicles near the interdigitation of the lens epithelial cells were observed in all of the 7 eyes examined histologically 2 weeks after the procedure. These changes were not observed in the 7 fellow control eyes. As a result, it is surmised that cataract formation after intravitreal silicone oil injection may be associated with morphological changes in the lens epithelial cells.

Animals↗