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Biomedical subjects

K Nemoto

Publications and source records attributed to K Nemoto.

At least 145 records · Page 8Linked to original sources
PubMed1994

Development of high-toughness resin for dental applications.

OBJECTIVES: The purpose of this study was to develop a heat-cured resin with improved toughness. Polyurethane dimethacrylate (PUDMA) with hard and soft segments in the chemical structure was synthesized using polyurethane diisocyanate and 2-HEMA. METHODS: The bulk polymerization of PUDMA, Bis-GMA, TEGDMA and MMA was carried out in a glass tube with 0.5 wt% of BPO at 60 degrees C for 24 h and 110 degrees C for 3 h. The physical and mechanical properties of these polymers were measured, i.e., the polymerization shrinkage, water sorption, transverse strength, modulus of elasticity, deflection and Knoop hardness of these polymerized methacrylates were determined. RESULTS: The volume shrinkage and the water sorption values of PUDMA were lower than those of Bis-GMA. The transverse strength and the modulus of elasticity of PUDMA were close to those of PMMA. The deflection of PUDMA, as determined by a bending test, was higher than any of the other cured resins tested. SIGNIFICANCE: These results suggest that PUDMA is an excellent toughened polymer. The fracture toughness of PUDMA is sufficient for crown and bridge resins and dental composites.

Acrylic Resins↗
PubMed1994

Current status of pregnancy in diabetic women. A comparison of pregnancy in IDDM and NIDDM mothers.

Pregnancy in diabetic patients was uncommon before 1960 in Japan. It has increased recently and there has been a 3-fold increase since 1971. Only 26% of the cases of diabetic pregnancy had IDDM; the rest of cases had NIDDM. The perinatal mortality of infants decreased from 10.8% in 1971-1975 to 1.1% in 1986-1990, but the incidence of congenital malformations remained at 5.7-8.2% during this period. From 1988 to 1992, we experienced 207 deliveries at the Diabetes Center, Tokyo Women's Medical College. The ratio of IDDM to NIDDM of the mothers was 33:67. The onset of diabetes of pregnant women occurred earlier and the duration of diabetes was longer in IDDM than in NIDDM (mean onset, 17.8 vs. 26.0 years; mean duration, 11.5 vs. 5.6 years). The prevalence of maternal complications was similar between the IDDM and NIDDM mothers. Proliferative retinopathy in NIDDM was often detected for the first time during pregnancy. Major congenital malformations were found in none of the infants of IDDM mothers but in 5.8% of the infants of NIDDM mothers. This is probably related to the poor management of diabetes in NIDDM before pregnancy.

Adult↗
PubMed1994

Effect of deoxyspergualin on vascular rejection in canine kidney transplantation.

Deoxyspergualin (DSG), an analogue of spergualin produced by Bacillus laterosporus, has a strong immunosuppressive effect in various transplantation models. In this study, we investigated the effect of DSG on vascular rejection in canine kidney transplantation. To enhance vascular rejection, donor-specific blood transfusion (DST) was carried out on days 28, 21 and 14 preceding kidney transplantation. After DST, the donor kidney was transplanted to the recipient iliac fossa. The recipient animals were divided into five groups: namely, Group 1 (n = 7), no treatment; Group 2 (n = 6), DST only; Group 3 (n = 5), DSG only (treated with DSG intravenously at 1.2 mg./kg./day for the first 3 days after transplantation, 1.0 mg./kg./day for the following 3 days and 0.8 mg./kg./day for the following 8 days); Group 4 (n = 6), DST and DSG treatment (same protocol as Group 3); and Group 5 (n = 5), DST and cyclosporine (CsA) (treated with CsA orally at 10 mg./kg./day for 14 days after transplantation). In Group 2, DST treatment significantly reduced kidney graft survival time (8.6 +/- 2.2 days) compared with Group 1 (14.1 +/- 5.5 days). Despite DST, DSG treatment (Group 4) significantly prolonged graft survival time (29.5 +/- 2.6 days), whereas treatment with CsA (Group 5) did not prolong survival time (14.1 +/- 5.5 days) (Group 4 versus 5, p < 0.01). The onset of rejection was significantly delayed in Group 4 (22.1 +/- 2.7 days) compared with Groups 2 (5.7 +/- 2.4 days) and 5 (13.0 +/- 5.7 days) (p < 0.01). In contrast, the interval between rejection onset and animal death was significantly reduced in Groups 2 (3.0 +/- 0.6 days) and 5 (2.4 +/- 1.0 days) compared with Group 4 (7.3 +/- 1.7 days) (p < 0.01). These findings suggest that DSG successfully prevented humoral-type (accelerated acute-type) rejections. Histologically, nonDST groups (Groups 1 and 3) showed minimum vascular rejection. In contrast, all recipients in Group 2 showed severe vascular rejection, as did 80% of CsA treated-animals (Group 5). Despite DST, however, 84% of DSG treated-animals (Group 4) showed minimal or mild vascular rejection and only 17% had severe rejection (Group 4 versus 5, p < 0.04). These data suggest that both clinically and histologically, DSG has more potent immunosuppressive effects against humoral and vascular rejection than CsA.

Animals↗
PubMed1994

Detection of Streptococcus mutans by PCR amplification of spaP gene.

Synthetic oligonucleotide primers were used in the polymerase chain reaction (PCR) to amplify a sequence of the spaP gene, which encodes the surface protein antigen I/II of Streptococcus mutans. A DNA fragment of c. 192 bp was amplified from lysed S. mutans cells or isolated DNA. With S. mutans cells, the lower limit of detection was 4-40 cfu. With these primers, 13 reference and 50 clinical strains of S. mutans were identified. Amplification of the 192-bp product was not demonstrated when 41 strains of other streptococcal and non-streptococcal species were tested. The spaP gene PCR has potential for the rapid diagnosis of S. mutans infections.

Adult↗
PubMed1994

Improvement of mitomycin C- and cyclophosphamide-induced thrombocytopenia and leucocytopenia by prior treatment with deoxyspergualin in dogs.

Deoxyspergualin (DGS) is a new immunosuppressant which has shown inhibitory haemopoietic activity. We investigated the myeloprotective effect of DSG against the haemopoietic injury of mitomycin C (MMC) or cyclophosphamide (CYC) by measuring peripheral blood cell numbers in dogs. DSG given at 5 mg/kg on days 3, 2 and 1 before, or at 10 mg/kg on either days 2 and 1 before or on day 1 before and the day of injection of MMC at 0.25 mg/kg ameliorated both the thrombocytopenia and leucopenia caused by MMC. This ameliorative effect was more evident on platelet counts than on white blood cell counts. In addition, the leucopenia and thrombocytopenia induced by a single injection of CYC at 10 mg/kg was also ameliorated by prior DSG administration. These findings suggest that DSG may be useful in protecting against the haemopoietic damage induced by chemotherapeutic agents in the treatment of cancer.

Animals↗
PubMed1994

Prognostic impact of the period between surgery and postoperative irradiation in esophageal carcinoma.

One hundred and sixty-two esophageal carcinomas curatively resected and followed by postoperative irradiation were analyzed to investigate whether the delay of postoperative irradiation affected the patients' prognosis. The period of 40 or more days between surgery and postoperative irradiation caused significantly worse survival rates, and this fact was true even if the survival rates were corrected by the other significantly important prognostic factors: age and tumor staging. The incidence of infield recurrence and cancerous death were higher in the patients with the waiting period of 40 or more days. Significant repopulation of residual tumor cells in curatively resected esophageal carcinomas begins 40 days after surgery, therefore, postoperative irradiation should be started within 40 days after a radical resection. The difference of survival rates as related to the waiting period became clear after the follow-up of more than four years. The prognostic difference of subclinical tumors seems to be uncovered several years after treatment.

Adult↗
PubMed1994

Effect of pretreatment reagent for enamel on the adhesion of resin composite.

Aqueous solutions of methacryloyl tyrosine amide (MTYA), glyceryl methacrylate (GM), glutaraldehyde and succinic acid were prepared and their effectiveness as pretreatment reagents was evaluated by measuring the tensile bond strengths between resin composite and polished enamel. Pretreatment of polished enamel with MTYA.GM.S3 (A: 6% MTYA + 70% GM aqueous solution, B: 3% succinic acid aqueous solution) gave bond strengths of about 7 MPa, whereas pretreatment with MTYA.G.GM.S3 (A: 6% MTYA + 70% GM aqueous solution, B: 3% succinic acid + 2% glutaraldehyde aqueous solution) gave values of about 5 MPa. The mean bond strengths of each after 60 s of scrubbing with MTYA.GM.S3 or by MTYA.G.GM.S3 were raised to about 9.5 MPa, and the type of bond failure was fracture of the bonding agent. Although there were no resin tags, it was found that resin composite was able to adhere to polished enamel without acid etching.

Acid Etching, Dental↗
PubMed1994

Effects of lining materials on the composite resins shrinkage stresses.

Recently, three types of lining materials have been used in dental clinics, conventional powder-liquid glass ionomer cement, light-cured powder-liquid glass ionomer cement and a light-cured single paste type. This study compared the effects of these lining materials on the shrinkage stress of light-cured composite resins during the early setting stage, when polymerization shrinkage occurs. After the second irradiation, the shrinkage stress of composite resins lined with light-cured powder-liquid type cements was approximately 1.0 to 2.2 MPa when the lining application was 1.5 mm and 0.5 mm thick, respectively, demonstrating that a thicker lining application decreased shrinkage stress. The single paste type was only slightly effective in reducing shrinkage stress in composite resins. Although the sample lined with conventional powder-liquid type showed that stresses were less affected by the thickness of the lining, and had the lowest shrinkage stress of all conditions tested, greater exfoliation from the composite resin or the cavity occurred compared to that occurring with other materials.

Acrylic Resins↗
PubMed1994

The novel immunostimulant N-563, an analogue of deoxyspergualin, promotes resistance to Candida albicans infection in mice.

An analogue of deoxyspergualin, N-563 has an immunostimulating activity whereas the mother compound has been found to be a potent immunosuppressant. In this study, the protective effect of the analogue against C. albicans infection was investigated in normal and immunosuppressed mice. In normal mice, N-563 treatment at 10 mg/kg for 3 days prior to infection significantly prolonged the survival time. In immunosuppressed mice treated with a single dose of cyclophosphamide 4 days prior to infection, N-563 at 3 and 10 mg/kg for 3 days prior to infection also significantly prolonged the survival time of mice. In addition, it augmented the phagocytic activity of neutrophils and enhanced the delayed type hypersensitivity reaction against C. albicans. Coincidentally, N-563 appeared to protect against secondary infection with C. albicans in the delayed type hypersensitivity-positive mice.

Adjuvants, Immunologic↗
PubMed1994

Therapeutic studies of the combination of deoxyspergualin and prednisolone in MRL/lpr mice with advanced lupus-like disease.

Female MRL/lpr mice develop lesions closely resembling human systemic lupus, and therefore can serve as models in order to examine the efficacy of immunosuppressive agents. The present study was designed to evaluate the efficacy of the combination of deoxyspergualin with prednisolone compared with each alone in 13-week-old female MRL/lpr mice. After the onset of lymphadenopathy, splenomegaly, and the elevation of plasma autoantibodies, deoxyspergualin alone or prednisolone alone was effective. An immunosuppressive regimen of deoxyspergualin combined with prednisolone was demonstrated to be superior to each single therapy concerning the amelioration of advanced disease in the MRL/lpr mice without increasing toxicity.

Animals↗
PubMed1994

[Psychological evaluation of patients by state-trait anxiety inventory in pain clinic].

In 84 outpatients who visited our pain clinic, we evaluated their anxiety before the first examination, using State-Trait Anxiety Inventory. State anxiety scores were high in all the patients regardless of their underlying disease. Trait anxiety scores in patients with chronic pain such as postherpetic neuralgia or cervic-shoulder-hand syndrome were higher than in patients with facial nerve palsy, sudden hearing loss or herpetic pain. This study indicates that psychosomatic management is mandatory for patients with chronic pain.

Adult↗
PubMed1994

[Meralgia paresthetica after spinal anesthesia].

A 27-year-old man underwent appendectomy under spinal anesthesia with 0.3% dibucaine 2.7 ml. The perioperative course was uneventful. The surgical procedure, however, lasted for 1.5 hours in the supine position. On the second postoperative day, a postspinal headache occurred and lasted for 18 days. On the seventh postoperative day the patient complained of numbness along the anterolateral aspect of the left thigh innervated by the lateral cutaneous nerve. There was no reflex or motor deficit indicative of the involvement of other nerves. The disorder was diagnosed as meralgia paresthetica caused by the surgical procedures. The numbness disappeared after the oral administration of mecobalamin in several days. In the treatment of a case like this, it is important to exclude neurological complications caused by spinal anesthesia.

Administration, Oral↗
PubMed1994

[Multiple cooperative study of UFT-adjuvant chemotherapy for malignant tumor in the jaw and oral cavities. The Oral Surgery Malignant Tumor Research Association in Kanto Kohshinetsu District].

We studied the usefulness and safety of long-term administration of uracil and tegafur (UFT) after primary therapy of the malignant tumor in jaw and oral cavity regions randomized controlled trial. 112 cases were totallized 6 institutes belonging to the Oral Surgery Malignant Tumor Research Association in Kanto Kohshinetsu District during 2 years and 10 months, beginning in September 1986. After completing the primary therapy, treatment was not performed in group A and 400 mg/day of UFT was orally administered in group B for 1 year. A variation was observed in the stages of background factors such as sex and age (more than 30 years old and less than 80 years old), while no such discrepancy was observed in other stages. No significant difference of 1-year-survival ratio and non-recurrence ratio was noted in either group, while the non-recurrence ratio was more favorable in group B than group A, and the usefulness of UFT for adjuvant chemotherapy was suggested. The incidence of side effects in group B was 42.6%, and no serious side effect was observed.

Adenocarcinoma↗
PubMed1994

[Spinal anesthesia for open reduction of tibial fracture in a patient with late cerebellar cortical atrophy].

We could successfully perform spinal anesthesia with bupivacaine for open reduction of tibial fracture in a patient with late cerebellar cortical atrophy (LCCA). LCCA is a very rare neurologic degenerative disorder localized chiefly in the cerebellum, and it may be followed by various complications. His postoperative course was uneventful, followed by no neurological complication. Regional anesthesia including spinal anesthesia seems to be safe for operations in patients with LCCA.

Anesthesia, Spinal↗
PubMed1994

[Intravenous lidocaine in the treatment of post treatment neuropathy].

A 46-yr-old man with a 3-month history of post treatment neuropathy following insulin treatment for diabetes mellitus was suffering from severe pain and dysesthesia in his bilateral feet and legs. The patient described his pain as constant burning sensation which was severest in the soles and extended circumferentially over the legs. Previous trials of tricyclic antidepressants and nonsteroidal antiinflammatory drugs were uneffective. The patient received a trial dose of intravenous lidocaine (200mg), which markedly decreased his pain. Subsequently, mexiletine was administered orally in a dose of 300 mg a day and the dose was increased up to 450 mg a day, by which a severity of pain was halved and anxiety was relieved one month later. In conclusion, intravenous lidocaine and oral mexiletine may be useful drugs for post treatment neuropathy.

Administration, Oral↗
PubMed1994

IgG-mediated anaphylactic contraction and 86Rb efflux from guinea pig tracheal smooth muscle.

Tracheal muscle strips isolated from guinea pigs passively sensitized with anti-egg albumin rabbit IgG were loaded with 86Rb as a K+ marker. The 86Rb efflux from the muscle tissue was measured after antigen exposure and the K(+)-channel subtypes involved in anaphylactic contraction were identified. The net 86Rb efflux was increased during antigen challenge. This increase was inhibited in Ca(2+)-free medium or in the medium of 40 mM of KCl, but not by 10 microM of glibenclamide or 20 mM of KCl. Decreased membrane potential and generation of action potentials were also observed during the anaphylactic contraction. As a comparison for antigen-induced 86Rb efflux changes, experiments using high concentrations of KCl were also performed. 86Rb efflux was increased depending on the KCl concentration. This increase was inhibited in Ca(2+)-free medium but not by 10 microM of glibenclamide. These results suggest that the K(+)-channel opening during IgG-mediated anaphylactic contraction was dependent on a decreased membrane potential due to 20-40 mM KCl. The subtype of the K(+)-channel involved is voltage-dependent K(+)-channel (Kv-channel), and Ca(2+)-activated K(+)-channel (KCa-channel) may also be involved in the 86Rb efflux change. The ATP-sensitive K(+)-channel (KATP-channel) was not involved in K(+)-channel opening during anaphylactic contraction.

Anaphylaxis↗
PubMed1994

Graft-versus-leukemia effect in allogeneic bone marrow transplantation in mice against several radiation-induced leukemias.

The intensity of graft-versus-leukemia (GVL) effect was studied using several radiation-induced leukemia cell lines (designated 8027, 8313, 9107, 7929) in MHC-compatible and -incompatible allogeneic bone marrow transplantation (BMT) of leukemia-bearing C3H mice. The results indicated that BMT from MHC-incompatible allogeneic (B10, B10.D2) donors consistently improved the survival of the treated mice compared with that in syngeneic (C3H) donors. However, BMT from MHC-compatible allogeneic (B10.BR, CBA, AKR) donors failed to improve the survival of 8027-bearing recipients. On the other hand, a remarkable improvement in survival of 8313, 9107 or 7929-bearing recipients was observed in MHC-compatible allogeneic (B10.BR, AKR) BMT but there was only a marginal GVL effect in MHC-compatible BMT from CBA donors. There was no clear correlation between the intensity of GVL effect and the amount of class I MHC molecules expressed on leukemic cell lines. The activity of donor lymph node cells for the induction of lethal graft-versus-host disease (GVHD) correlated with the intensity of GVL effect induced by intact donor bone marrow. The results indicate that GVL effect against radiation-induced leukemias could be consistently induced in MHC-incompatible allogeneic BMT whereas the intensity of GVL effect induced in MHC-compatible allogeneic BMT varied among different leukemias and the donor-host strain combinations used.

Animals↗