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T Nikaido

Publications and source records attributed to T Nikaido.

At least 37 records · Page 2Linked to original sources
PubMed2001

Four new triterpenoid saponins from Conyza blinii.

Three new bisdesmosidic saponins named conyzasaponins A, B, and C (1-3) and one new monodesmosidic saponin, conyzasaponin G (4), were isolated from the aerial parts of Conyza blinii. Their structures were elucidated on the basis of extensive NMR (DEPT, DQF-COSY, HOHAHA, HMQC, HMBC, and NOESY) and MS studies. Compounds 1-3 share a common prosapogenin, bayogenin 3-O-beta-D-xylopyranosyl-(1-->3)-beta-D-glucopyranoside, which is identical with conyzasaponin G (4), and differ in the structures of the ester-linked sugar moieties at C-28. Conyzasaponin A (1) is the 28-O-beta-D-apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl ester, conyzasaponin B (2), the 28-O-beta-D-apiofurano- syl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl ester, and conyzasaponin C (3), the 28-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-[beta-D-apiofuranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl ester of the prosapogenin, respectively.

Carbohydrate Sequence↗
PubMed2001

Bonding amalgam to enamel: shear bond strength and SEM morphology.

STATEMENT OF PROBLEM: Most studies of amalgam bonding have used dentin as the substrate. There is little data on bonding to enamel. PURPOSE: This study evaluated the shear bond strength of amalgam to enamel with the use of 3 resin cements, 1 resin-modified glass ionomer lining cement, and 2 dentin bonding agents. MATERIAL AND METHODS: Sixty bovine teeth were trimmed to expose a flat enamel surface and randomly assigned to 6 test groups of 10 specimens each. A single-plane lap shear test assembly was used. The enamel surfaces were treated with either Amalgambond Plus (group I, control), 2 coats of Amalgambond Plus (group II), light-polymerized Panavia F followed by an additional coat of autopolymerized Panavia F (group III), light-polymerized Fuji Lining LC followed by an additional coat of acid-base set Fuji Lining LC (group IV), Clearfil SE Bond followed by an additional coat of autopolymerized Panavia F (group V), or Single Bond followed by an additional coat of autopolymerized RelyX ARC (group VI). Freshly mixed amalgam was condensed against the treated enamel surfaces. Shear bond strengths for each group were compared with 1-way ANOVA and post hoc Duncan's test (P=.05). Fracture modes were examined visually. SEM observations of the fractured enamel surfaces, interfacial morphology, and conditioned enamel surfaces for each group were performed. RESULTS: Low bond strengths of 1.2 and 1.6 MPa were obtained in groups VI and I, respectively. The dual application of materials in all remaining groups resulted in higher bond strengths that ranged from 14.2 to 15.7 MPa. SEM illustrations revealed various degrees of intermingling between the adhesive material and amalgam. The conditioned enamel surfaces were morphologically varied according to conditioning solution. CONCLUSION: In this in vitro study, with the exception of group VI, the dual application of either adhesive resins or resin-modified glass ionomer resulted in satisfactory bond strengths of amalgam to enamel (up to 16 MPa).

Acid Etching, Dental↗
PubMed2001

Demonstration of focal p53 expression without genetic alterations in endometriotic lesions.

Their monoclonal origin (as indicated by recent investigations) indicates the neoplastic nature of most endometriotic lesions. p53, a representative tumor suppressor, regulates cell proliferation, and genetic alterations in p53 are involved in carcinogenesis in a wide variety of human cancers. The aim of this study was to examine endometriotic lesions for p53 expression and genetic alterations in p53. An immunohistochemical study revealed that 20% (13/64) of endometriotic lesions showed focal p53 expression in the epithelial cells. Using serial paraffin sections, we employed a microdissection method to extract DNA from the endometriotic tissues that showed p53 expression. No mutations were found in exons 5-8 in p53 by cleavase fragment length polymorphism scanning and polymerase chain reaction-DNA sequencing. Moreover, neither loss of heterozygosity nor microsatellite instability was detected at the microsatellite marker sites of p53. These results suggest that the focal p53 expression recognized in the endometriotic epithelia may be due to overproduction of wild-type p53 protein.

Adult↗
PubMed2001

Sensitized increase of period gene expression in the mouse caudate/putamen caused by repeated injection of methamphetamine.

Methamphetamine (MAP) causes the sensitization phenomena not only in MAP-induced locomotor activity, dopamine release, and Fos expression, but also in MAP-induced circadian rhythm. Cocaine-induced sensitization is reportedly impaired in Drosophila melanogaster mutant for the Period (Per) gene. Thus, sensitization may be related to induction of the Per gene. A rapid induction of mPer1 and/or mPer2 in the suprachiasmatic nucleus after light exposure is believed to be necessary for light-induced behavioral phase shifting. Although the caudate/putamen (CPu) expresses mPer1 and/or mPer2 mRNA, the function of these genes in this nucleus has not yet been elucidated. Therefore, we examined whether MAP affects the expression of mPer1 and/or mPer2 mRNA in the mouse CPu. Injection of MAP augmented the expression of mPer1 but not mPer2 or mPer3 in the CPu, and this MAP-induced increase in mPer1 expression lasted for 2 h. Also, the MAP-induced increase of mPer1 mRNA was strongly antagonized by pretreatment with a dopamine D1 receptor and N-methyl-D-aspartate (NMDA) receptor antagonist, but not by a D2 receptor antagonist. Interestingly, application of either the D1 or the D2 agonist alone did not cause mPer1 expression. The present results demonstrate that activation of both NMDA and D1 receptors is necessary to produce MAP-induced mPer1 expression in the CPu. Repeated injection of MAP caused a sensitization in not only the locomotor activity but also mPer1 expression in the CPu without affecting the level of mPer2, mPer3, or mTim mRNA. Thus, these results suggest that MAP-induced mPer1 gene expression may be related to the mechanism for MAP-induced sensitization in the mouse.

Animals↗
PubMed2001

Genetic alterations in microsatellite marker sites among tumor suppressor genes in endometriosis.

Four endometriotic lesions were examined for the presence of genetic alterations in microsatellite marker sites among eight tumor suppressor genes. For this, a microdissection method was used on paraffin sections. Only one instance of loss of heterozygosity was detected at the PTCH locus. Heterozygosity was retained (indicating the absence of both loss of heterozygosity and microsatellite instability) at the other seven tumor suppressor gene loci in all the cases. Among the tumor suppressor genes examined, genetic defects in these microsatellite regions are certainly not ubiquitous in endometriosis and may be uncommon.

Adult↗
PubMed2001

Up-regulation of p27Kip1 by progestins is involved in the growth suppression of the normal and malignant human endometrial glandular cells.

Progestins are known to suppress the growth of normal human endometrial glands and endometrial carcinomas possessing PRs. To elucidate the molecular mechanisms of progestin-induced growth inhibition, the expression and functional involvement of p27Kip1 (p27), a cyclin-dependent-kinase inhibitor, was investigated using cultured normal endometrial glandular cells and endometrial carcinoma cell lines (Ishikawa; PR-positive, KLE; PR-negative). Growth of the normal endometrial glandular cells and Ishikawa cells was suppressed by treatment with progesterone and medroxyprogesterone acetate, respectively, in association with an increase in p27 protein expression. Immunoprecipitation revealed that progestins accelerated the complex formation of p27 and cdk2 in both types of cells. However, treatment with progestins did not show any marked alterations in the mRNA expression of p27 in either normal glandular cells or Ishikawa cells. On the other hand, p27 protein degradation experiments indicated that treatment with progesterone and medroxyprogesterone acetate prolonged the degradation time of the normal endometrial glandular cells and Ishikawa cells, respectively. Forced expression of the p27 protein using a p27 expression plasmid reduced the growth activity of normal endometrial glandular cells. These findings suggest that p27 is functionally involved in progestin-induced growth suppression of normal and malignant endometrial epithelial cells and that up-regulation of the p27 protein by progestins possibly occurs via posttranslational mechanisms.

Cell Cycle Proteins↗
PubMed2001

New triterpenoid saponins from Maesa tenera.

Two new triterpenoid saponins, maetenosides A and B were isolated from the aerial parts of Maesa tenera and were respectively defined as 3-O-[beta-D-glucopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->3)][beta-D-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl camelliagenin A 22-O-angelate (1) and 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->3)][beta-o-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl camelliagenin A 22-O-angelate (2). Their structures were established on the basis of chemical and spectroscopic methods.

Carbohydrate Conformation↗
PubMed2001

Fargosides A-E, triterpenoid saponins from Holboellia fargesii.

Five new triterpenoid saponins, fargosides A, B, C, D, and E, were isolated from the roots of Holboellia fargesii. The structures of fargosides A-E were elucidated on the basis of chemical and physicochemical evidence and found to be 3beta,20alpha-dihydroxy-29-norolean-12-en-28-oic acid 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (1), 3beta,20alpha,24-trihydroxy-29-norolean-12-en-28-oic acid 23-O-beta-D-fucopyranosyl-(1-->2)-[alpha-L-arabinopyranosyl-(1-->3)]-beta-D-glucopyranoside (2), 3beta,23-dihydroxy-30-norolean-2,20(29)-dien-28-oic acid 3-O-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-glucopyranosyluronic acid-(1-->3)]-alpha-L-arabinopyranoside (3), 3beta,23-dihydroxy-30-norolean-12,20(29)-dien-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (4), and 3beta,23-dihydroxy-olean-12-en-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (5), respectively.

Drugs, Chinese Herbal↗
PubMed2001

[Usefulness of immunohistochemistry as a diagnostic tool for tumors and pseudotumoral bone lesions].

Immunohistochemical study for the diagnosis of bone tumors and tumor-like lesions has to be scheduled after an appropriate analysis of clinical data, radiological findings, and results of histology in H-E sections. The value of several markers for osteoblasts is discussed, chiefly for various forms of osteosarcomas. In the same way, the role of S-100 protein as well as anticollagen type II antibody is developed for cartilaginous tumors. The selection of markers in the fields of round cell tumors and spindle cell tumors of bone is also discussed. Some diagnostic problems with the support of immunohistochemistry are described, like chordomas versus chondrosarcomas or bone metastases. Lastly, immunohistochemical study of proliferating factors in the bone tumor field is quoted.

Autoantibodies↗
PubMed2000

Enhancement of antitumor effect of bleomycin by low-voltage in vivo electroporation: a study of human uterine leiomyosarcomas in nude mice.

Uterine leiomyosarcoma is an extremely malignant neoplasm with high rates of distant metastasis, and systemic chemotherapy is not particularly effective. Thus, the introduction of more active anticancer agents, or of a new drug delivery system, is urgently needed. Recently, electrochemotherapy has been introduced as a way of enhancing the cytotoxic effects of chemotherapeutic agents. This involves administering the drug in combination with electric pulses (which permeabilize tumor cell membranes and allow the drug to enter the cells). In particular, bleomycin (BLM) cannot cross the plasma membrane efficiently, but its cytotoxicity can be enhanced by electropermeabilization. The aim of the present study was to investigate the effect of low-voltage electroporation (EP) in combination with local BLM injection on the growth of uterine leiomyosarcoma in nude mice. Human uterine leiomyosarcoma cells (SK-LMS-1) were implanted subcutaneously into nude mice. Tumor growth in mice treated with EP (100 V/cm) plus BLM was compared with that in mice receiving BLM alone, EP alone, or no treatment (controls). Tissue BLM concentrations and histological analysis (including mitotic counts) were evaluated in tumor tissues. There was a significant reduction in tumor growth in mice that received EP with BLM. One hour after the treatment, the local BLM concentration was 10 times higher in the tumors that received EP with BLM than in those receiving only BLM. Moreover, the mitotic count was lower in the tumors that received EP plus BLM than in the controls. These results demonstrate the possible therapeutic value of low-voltage EP with BLM in human uterine leiomyosarcoma.

Animals↗
PubMed2000

Dimensional changes of demineralized dentin treated with HEMA primers.

OBJECTIVES: The purpose of this study was to measure the dimensional changes of demineralized dentin before and after application of HEMA (2-hydroxyethyl methacrylate) by confocal laser scanning microscopy (CLSM). METHODS: The middle portion of bovine dentin was ground, polished, and covered with a vinyl tape with a 4-mm hole punched through it. A strip of polysiloxane impression material was then placed across the center of the dentin surface to preserve a strip of the original unetched surface. Dentin surfaces were etched with 32% phosphoric acid for 60 s and rinsed with water. The impression material was then removed and the following sequential steps were performed: the dentin surface was mildly air-dried, then strongly air-dried, then treated with either 35 wt.% HEMA/water or 100 wt.% HEMA and mildly air-dried, and then strongly dried again. The shrinkage of the demineralized dentin surface from the original unetched level was measured by CLSM in each step and results analyzed by one-way ANOVA. RESULTS: The dimensional changes of demineralized dentin after mild air drying were approximately -1 micron and, following strong air drying, resulted in -5 microns shrinkage. Following the application of 35 wt.% HEMA/water, the height of the demineralized dentin changed to a level of -3.3 microns, but then shrank to -4.8 microns after strong drying. ANOVA indicated that re-expansion of the shrunken etched dentin was significant (p < 0.05); however, the treated surface collapsed when it was strongly dried again (p < 0.05). 100% HEMA did not re-expand the shrunken demineralized dentin under any of the application on protocols (p > 0.05). SIGNIFICANCE: Thirty-five wt.% HEMA in water re-expanded the collapsed demineralized dentin matrix, however not to the original level. One hundred wt.% HEMA did not cause any re-expansion.

Acid Etching, Dental↗
PubMed2000

The influence of storage solution on dentin bond durability of resin cement.

OBJECTIVES: This study was conducted to determine the influence of storage solution on the bond durability of three resin cements to bovine dentin over the period of 1 year. METHODS: Ten bovine dentin specimens were tested for shear bond strength with each material (Panavia 21, Kuraray Co.; BISTITE, Tokuyama Co; MASA Bond, Sun Medical Co.) and storage mode, listed below. Four storage environments were studied as follows: water changed every day for 1 year; water unchanged for 1 year; Phosphate Buffered Saline (PBS) changed every week over 1 year; PBS unchanged for 1 year. Ten teeth were also tested for each material at 1 day as a control. The mode of failure was classified after fracture of the bonds by SEM observation. The means of the bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (p < 0.05). Results for the mode of fracture were analyzed using the Mann-Whitney U test. RESULTS: Although there was no statistical difference in the mean bond strengths between the water and PBS storage solutions (p > 0.05) in all cements, the results for the shear bond strengths in the changed storage solution groups were significantly lower than those where the storage solution remained unchanged (p < 0.05). There were statistical differences between the 1 day results and the changed water groups among all cements (p < 0.05). SIGNIFICANCE: The storage condition influenced the long-term durability of dentin bonding with resin cements.

Adhesiveness↗
PubMed2000

Effect of hydrostatic pressure on regional bond strengths of compomers to dentine.

OBJECTIVES: The aim of this study was to evaluate the effect of hydrostatic pressure on the regional bond strengths of compomers to dentine. METHODS: Thirty freshly extracted molars were ground flat to expose the dentine and randomly divided into two groups for bonding: no hydrostatic pressure and hydrostatic pressure of 15cm H(2)O. Xeno CF, Dyract AP and F 2000 were applied to dentine surfaces pretreated by the respective bonding systems following the manufactures' instructions, and then restored with Clearfil AP-X. After 24h storage in water, the teeth were sectioned into 0.7-mm thick slabs and visually divided into three regional subgroups: the region communicating with the pulp through dentinal tubules (pulp horn); the region between the pulp horns (center); and the region between the pulp horn and DEJ (periphery). The specimens were trimmed to a cross-sectional area of 1mm(2) and subjected to the micro-tensile bond test. The data were analyzed by one- and three-way ANOVA, and Fisher's PLSD (p<0.05). RESULTS: There were no significant regional differences of bond strengths for all the compomers tested (p>0.05). However, hydrostatic pressure significantly decreased the bond strength of F 2000 to all regions (p<0.05), while the bond strength of Dyract AP significantly decreased only at the pulp horn region (p<0.05). On the other hand, the bond strengths of Xeno CF seemed not to be affected by hydrostatic pressure (p>0.05). For Dyract AP and F 2000, the fracture modes were affected by hydrostatic pressure, while, for Xeno CF, there were no significant differences between the fracture modes with non- or positive hydrostatic pressure. SIGNIFICANCE: Simulated pulpal pressure of 15cm H(2)O had a greater influence on the bond strengths of compomers to dentine than did dentine regions. Therefore, when measuring the bond strengths of compomers to dentine under the simulated in vivo conditions, the wetness of the dentine surface, as well as the intrinsic properties of each material should be seriously considered.

Analysis of Variance↗
PubMed2000

HCG promotes proliferation of uterine leiomyomal cells more strongly than that of myometrial smooth muscle cells in vitro.

Uterine myomas often enlarge rapidly during pregnancy. This rapid increase in size may imply that human chorionic gonadotrophin (HCG) influences cell proliferation in uterine leiomyomata. To assess the direct effect of HCG on normal uterine smooth muscle and uterine leiomyomata, we investigated cell proliferation and the expression of cell cycle-related proteins in these cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that HCG/LH receptor was present in both cultured myometrial and leiomyomal cells. Treatment with HCG significantly increased cell proliferation in both myometrial and leiomyomal cells (P < 0.03), especially at an early phase in the 9 day culture. The increase in the viable cell number induced by HCG treatment was significantly greater in leiomyoma cells than in myometrial cells on day 3 in culture (P < 0.03). In leiomyomal cells, the expression of proliferating cell nuclear antigen (PCNA), cyclin E and cdc2 was significantly increased by HCG treatment (P < 0.05) even at the lowest concentration used (3 nmol/l). In myometrial cells, the expression of cyclin E and cdc2 was significantly increased by HCG treatment (P < 0.05) only at the highest concentration used (30 nmol/l). These results suggest that HCG directly promotes the proliferation of myometrial and leiomyomal cells, with the latter showing the greater response of the two.

Adult↗
PubMed2000

Nematocidal activity of quassinoids against a species of Diplogastridae.

The nematocidal activity of 38 quassinoids, C19 or C20 compounds isolated from Simaroubaceae, was measured using a species of Diplogastridae (Nematoda) to develop lead parasiticides. Of the various quassinoids tested, samaderines B and E displayed the most potent nematocidal activity with a minimum lethal concentration (MLC) of 2.0 x 10(-5) M. The nematocidal activities of samaderines B and E were 15-fold greater than that of albendazole (3.0 x 10(-4) M), 10-fold greater than that of thiabendazole (2.0 x 10(-4) M) and 7.5-fold greater than that of avermectin (1.5 x 10(-4) M). Thus, samaderines B and E may eventually be used as lead parasiticides. In light of the relationship between the structures of quassinoids and their nematocidal activities, those with potent nematocidal activity may require the elements mentioned. These results should help to further our understanding of nematocidal activity.

Animals↗
PubMed2000

[MALT lymphoma of the larynx].

We describe a 25-year-old Japanese woman with a MALT-type lymphoma of the larynx. She presented with a one-year history of hoarseness and increasing pain in the larynx. A small tumor was found on the left side of the false cord, and was biopsied under laryngoscopy in the department of laryngology. Histological examination showed the presence of centrocyte-like cells infiltrating the submucosa and forming lymphoepithelial lesions. The neoplastic cells were CD20+, CD79a+, and CD5-. Staining for keratin with CAM 5.2 highlighted the infiltrated epithelium. Analysis of DNA extracted from the biopsy specimen showed a clonal immunoglobulin heavy chain gene rearrangement, confirming the histological diagnosis of extranodal marginal zone B-cell lymphoma of the MALT type. To our knowledge, only 6 cases of MALT lymphoma of the larynx have been reported previously. The presence of MALT lymphomas arising at rare sites emphasizes the importance of accurate diagnosis and appropriate clinical management. Patients require careful periodic evaluation in order to time the therapy appropriately, and to avoid overtreatment and complications of therapy, including secondary malignancies.

Adult↗
PubMed1999

Thioredoxin-dependent redox regulation of p53-mediated p21 activation.

Thioredoxin (TRX) is a dithiol-reducing enzyme that is induced by various oxidative stresses. TRX regulates the activity of DNA-binding proteins, including Jun/Fos and nuclear factor-kappaB. TRX also interacts with an intranuclear reducing molecule redox factor 1 (Ref-1), which enhances the activity of Jun/Fos. Here, we have investigated the role of TRX in the regulation of p53 activity. Electrophoretic mobility shift assay showed that TRX augmented the DNA binding activity of p53 and also further potentiated Ref-1-enhanced p53 activity. Luciferase assay revealed that transfection of TRX enhanced p53-dependent expression of p21 and further intensified Ref-1-mediated p53 activation. Furthermore, Western blot analysis revealed that p53-dependent induction of p21 protein was also facilitated by transfection with TRX. Overexpression of transdominant negative mutant TRX (mTRX) suppressed the effects of TRX or Ref-1, showing a functional interaction between TRX and Ref-1. cis-Diamminedichloroplatinum (II) (CDDP) induced p53 activation and p21 transactivation. The p53-dependent p21 transactivation induced by CDDP was inhibited by mTRX overexpression, suggesting that TRX-dependent redox regulation is physiologically involved in p53 regulation. CDDP also stimulated translocation of TRX from the cytosol into the nucleus. Hence, TRX-dependent redox regulation of p53 activity indicates coupling of the oxidative stress response and p53-dependent repair mechanism.

Carbon-Oxygen Lyases↗