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Y Oda

Publications and source records attributed to Y Oda.

At least 361 records · Page 20Linked to original sources
PubMed1995

A comparative study of nuclear morphometry and proliferating activity in neuroectodermal tumors of bone and Ewing's sarcoma of bone.

A neuroectodermal tumor of bone (NTB) is a small round cell tumor with Homer Wright rosettes. The differences in the nuclear profiles, proliferating activities, and biologic behavior between NTB and Ewing's sarcoma of bone (ESB) are still controversial. In this study, 11 cases of NTB and 12 cases of ESB were compared by a nuclear morphometrical approach using an image analyzer. In addition, the proliferative activity was also evaluated between the two groups by an immunohistochemical study using proliferating cell nuclear antigen (PCNA). The nuclei of NTB were found to be significantly more elliptical (Form Ell: NTB = 0.725, ESB = 0.743, P = 0.017) and irregular (Form Ar: NTB = 0.908, ESB = 0.933, P = 0.046) than those of ESB. The maximum diameter of the nuclei in NTB was larger than those of ESB (NTB = 6.92 micron, ESB = 6.33 micron, P = 0.017), however, there were no significant differences in the nuclear area between the two groups. Immunohistochemically, the mean PCNA score of the NTB (10 cases) were significantly higher than those of ESB (7 cases) (NTB = 25.9, ESB = 11.6, P = 0.005). The mitotic activities of NTB (17/10HPF) were also higher than ESB (6/10HPF) (P = 0.0008). There were no significant differences between the two groups in survival (log-rank test: P = 0.324) according to our small series. Our results suggest that these two tumors should be separated because their proliferating activity is different and they can be separated by some nuclear profiles.

Adolescent↗
PubMed1995

Expression of growth factors and their receptors in human osteosarcomas. Immunohistochemical detection of epidermal growth factor, platelet-derived growth factor and their receptors: its correlation with proliferating activities and p53 expression.

The expression of both epidermal growth factor (EGF) and platelet-derived growth factor (PDGF), and of their receptors (EGFR and PDGFR) was immunohistochemically examined in 37 cases of osteosarcoma. Furthermore, immunostaining for p53 protein and Ki-67 antigen by MIB-1 was carried out and compared with the above results. EGFR (81%) expressed more often than EGF (51%) and the expression of EGF and EGFR, and PDGF and PDGFR were recognized in 49% and 38%, respectively. In eleven cases (30%), the expression of both growth factors and their receptors was combined. Anaplastic osteosarcoma showed higher MIB-1 index than osteoblastic and fibroblastic subtypes (P < 0.05). High grade osteosarcomas (G3 and G4) revealed higher MIB-1 index compared with low grade tumors (G1 and G2). PDGF positive tumors (MIB-1 index: 20.0) showed significantly higher proliferation compared with PDGF negative tumors (MIB-1 index: 6.5) (P < 0.01). Five out of 37 cases (13.5%) showed positive immunoreaction for p53. There was no correlation of p53 status with MIB-1 index and the expression of growth factors or their receptors. Our results suggest that PDGF expression may be an important mediator of cell proliferation control, via an autocrine mechanism, in human osteosarcoma.

Antibodies, Monoclonal↗
PubMed1995

Evaluation of dimensional stability of elastomeric impression materials during disinfection.

Disinfection of impression materials is recommended for preventing cross-contamination in dental clinics. However, aspects of the evaluation of elastomeric impression materials only slightly subjected to the effects of disinfectants have not been established. Therefore, the effects of sodium hypochlorite, glutaral, iodine, and ethanol disinfectants on elastomeric impression materials, condensation silicone, polysulfide, addition-type silicone (vinyl silicone), hydrophilic vinyl silicone, and polyether, were evaluated directly in a time-dependent manner by a non-contact displacement meter. Condensation silicone impression materials and polysulfide rubber impression materials greatly shrank over time, but their shrinkage decreased with immersion in disinfectants. Vinyl silicone impression materials and polyether impression materials showed excellent dimensional stability in air. However, hydrophilic vinyl silicone impression materials and polyether impression materials expanded greatly when immersed in disinfectants, especially when immersed in ethanol. Hydrophobic vinyl silicone impression materials showed excellent dimensional stability regardless of the presence or absence of disinfectants.

Dental Impression Materials↗
PubMed1995

An application of powder metallurgy to dentistry.

Generally, the dental casting method is used to fabricate dental prostheses made with metal. The method of fabricating dental prostheses from sintered titanium alloy has certain advantages: the elimination of casting defects, a sintering temperature that is lower than the melting point, and a shorter processing time. By examining (1) the properties of green, sintered compacts of titanium powder, (2) the effects of adding aluminum powder on the properties of green, sintered compacts of Ti-Al compound, and (3) the effects of adding copper powder on the properties of green, sintered compacts of Ti-Al-Cu compound, the authors developed a sintered titanium alloy on a trial basis. Because the properties satisfied the requirements of dental restorations, a powder metallurgical method of making dental restorations from this sintered titanium alloy was devised. Applications of such sintered titanium alloys for the metal coping of metal-ceramic crowns and denture base plates were discussed.

Aluminum↗
PubMed1994

Transcriptional regulation of basic fibroblast growth factor gene by p53 in human glioblastoma and hepatocellular carcinoma cells.

Mutations of the p53 gene are found in various human cancers. The frequency of its mutation is reported to increase during tumor progression in most tumors. In human gliomas, mutations of the p53 gene are found in about one-third of the malignant forms and in few of the benign ones, indicating their possible involvement in tumor progression. On the other hand, we have recently shown that basic fibroblast growth factor (basic FGF) plays a crucial role in tumor progression as an autocrine growth factor in tissues of human gliomas. Therefore, we hypothesized that p53 might regulate the promoter activity of the basic FGF gene, which has several GC boxes and no typical TATA box. In this study, cotransfection assays using human glioblastoma and hepatocellular carcinoma cells and establishment of stable cell lines expressing mutant-type p53 were performed. The basic FGF gene promoter was demonstrated to be regulated by p53 at the transcriptional level and its basal core promoter was found to be responsive to p53. Expression of endogenous basic FGF was also demonstrated to be activated by mutant type p53. Wild-type p53 repressed gene expression of the basic FGF and its mutant activated it in vitro, implying one of the possible pathways in tumor progression.

Carcinoma, Hepatocellular↗
PubMed1994

The role of cerebrospinal fluid cytology in radiotherapy planning for intracranial germinoma.

PURPOSE: The association between the cerebrospinal fluid cytology findings and the clinical features of patients with intracranial germinoma was investigated to determine whether cerebrospinal fluid cytology could be helpful in determining the optimal radiation treatment volume. METHODS AND MATERIALS: Between 1976 and 1992, cerebrospinal fluid cytology was performed in 42 germinoma patients using a cytocentrifugation method. Forty patients received irradiation and 2 received chemotherapy with cisplatin and etoposide. RESULTS: Cerebrospinal fluid cytology was positive in 22 of the 42 patients (52%). Dissemination via cerebrospinal fluid (intraventricular or spinal) was present at the initial diagnosis in eight (36%) of the 22 cytology-positive patients and none of the 20 negative patients. After treatment, cerebrospinal fluid dissemination developed in four (18%) of the cytology-positive patients and one (5%) of the negative patients. Two of the former four patients had received chemotherapy alone as initial treatment. Five patients with positive cytology received irradiation to a smaller volume than the cerebrospinal axis (primary tumor site plus spinal axis in three and whole brain in two), but they have not developed recurrence in the 4 to 14 years since therapy. The 5-year survival rate was 93% for the cytology-positive patients and 94% for the negative patients. CONCLUSION: Cerebrospinal fluid cytology-positive patients have a higher risk of cerebrospinal fluid dissemination and it seems reasonable to give them low-dose (20-24 Gy) prophylactic craniospinal irradiation. When properly irradiated, the prognosis of cytology-positive patients is as good as that of negative patients.

Adolescent↗
PubMed1994

Transfection with a bcl-2 expression vector protects transplanted bone marrow from chemotherapy-induced myelosuppression.

The use of cytokines such as granulocyte-colony-stimulating factor (G-CSF) to ameliorate chemotherapy-induced myelosuppression may not only stimulate the recovery of normal hematopoietic cells but may also enhance the proliferation of the tumor cells with functional receptors for these cytokines. In this study, we show that administration of recombinant human (rh) G-CSF decreased the in vitro and in vivo cytotoxic effects of Adriamycin or etoposide on L1210 murine leukemic cells with receptors for rhG-CSF. Transplantation of bone marrow cells expressing high levels of bcl-2 from a retroviral construct [MPZenNeo(bcl-2)] (bcl-2-BMT) did not decrease the in vivo cytotoxic effect of etoposide on L1210 cells, but enabled recovery of myelopoiesis following etoposide-induced myelosuppression to almost the same extent as did the administration of rhG-CSF. These findings suggest the possibility that bcl-2 transfection could be used to protect transplanted bone marrow from chemotherapy-induced myelosuppression on behalf of administration of rhG-CSF, in case of treatment of tumors with functional receptors for rhG-CSF.

Animals↗
PubMed1994

Individual ionization constants of all the carboxyl groups in ribonuclease HI from Escherichia coli determined by NMR.

All of the individual carboxyl groups (the side-chain carboxyl groups of Asp and Glu, and the C-terminal alpha-carboxyl group) in Escherichia coli ribonuclease HI, which is an enzyme that cleaves the RNA strand of a RNA/DNA hybrid, were pH-titrated, and their ionization constants (pKa) were determined from an analysis of the pH-dependent chemical shifts of the carboxyl carbon resonances obtained from 1H-13C heteronuclear two-dimensional NMR. The pKa values in the enzyme varied widely among individual residues, for example, in the unusual pKa values for two important catalytic residues, Asp10 (pKa 6.1) and Asp70 (pKa 2.6). Moreover, remarkable two-step titrations were observed for these carboxylates. The binding of Mg2+ ion to the enzyme, which is the cofactor necessary for catalytic activity, caused no significant change in the pKa values of the carboxyl groups, except for that of Asp10. The variations of the pKas that were dependent on the microenvironment in the protein were theoretically reproduced to compare with the experimental results by a numerical calculation, using a continuum electrostatic model. Most of the significant pKa decreases were brought about through strong electrostatic interactions with the neighboring basic amino acids, Arg or Lys. The pKa shifts and the two-step titrations of Asp10 and -70, which are close to each other, were interpreted to be due to the neighboring effect of two functional groups, as observed in the interacting titratable groups of a dicarboxyl compound or in the active site carboxylates of lysozyme and aspartic protease. The role of Asp10 in the catalytic action is either to be the proton donor to the RNA moiety or the binding partner of the Mg2+ ion cofactor. Asp70, on the other hand, is considered to be the proton acceptor from a water molecule.

Amino Acid Sequence↗
PubMed1994

Metabolism of lidocaine by rat pulmonary cytochrome P450.

The metabolism of lidocaine was studied using microsomes from extrahepatic tissues of rats, including lung, kidney and brain, or using a reconstituted system with purified CYP2B1 and CYP4B. Rat pulmonary microsomes metabolized lidocaine to an N-deethylated metabolite, monoethylglycinexylidide (MEGX). Renal microsomes produced MEGX and 3-hydroxylidocaine (3-OH LID), although the rate of MEGX formation was much lower in renal than in pulmonary microsomes. Other metabolites were not detected. Lidocaine was not metabolized by brain microsomes. In extrahepatic tissues, pulmonary microsomes had the highest activity. Hence, two major forms of cytochrome P450 isozymes, CYP2B1 and CYP4B1, in rat pulmonary microsomes were used for further study. The study with a reconstituted system using purified cytochrome P450 isozymes revealed that only CYP2B1 showed lidocaine deethylation activity; the other form of cytochrome P450 in the lung, CYP4B1, did not. The Michaelis-Menten constant for lidocaine N-deethylation by rat pulmonary microsomes was 0.27 mM. Antibody against CYP2B1 completely inhibited the formation of MEGX by pulmonary microsomes. These results suggest that lidocaine is metabolized by rat lung, including CYP2B1.

Animals↗
PubMed1994

Microscale determination of dissociation constants of multivalent pharmaceuticals by capillary electrophoresis.

Dissociation constants (pKaS) of acidic, basic, and amphoteric pharmaceuticals were exactly determined by capillary electrophoresis. A general equation for use in calculation of pKaS from solute mobilities observed at different pHs was derived to be suitable for a multivalent compound with close pKaS such as angiotensins, which are bioactive octa- or decapeptides. The obtained pKa values were highly consistent with the values determined by conventional methods. For verapamil, the detection limit was 9.8 microM (49 fmol), the total analysis time was 12 min, and the relative standard deviation of the obtained pKa value was 0.11%. This method was also applicable to a mixture of two components, e.g., a bioactive compound and the prodrug, because they have different mobilities and are separated from each other.

Amino Acid Sequence↗
PubMed1994

Prognostic factors of colorectal cancer: K-ras mutation, overexpression of the p53 protein, and cell proliferative activity.

Between June 1990 and April 1991, 62 colorectal tumors were assessed in a prospective fashion on the basis of various tumor characteristics. Parameters included K-ras mutation, overexpression of the p53 protein, and proliferating cell nuclear cell antigen, as well as standard histopathologic examination. A multivariate analysis showed that K-ras mutation correlated with vascular invasion (P < 0.01) and hematogenous metastasis (P < 0.01). With regard to survival time, multivariate analyses using the Cox proportional hazard model suggested that status of lymph node metastasis (P < 0.01, relative risk [rr] = 7.27), TNM stage (P < 0.05, rr = 5.37), lymphatic invasion (P < 0.05, rr = 4.48), and K-ras mutation (P < 0.06, rr = 3.69) are the most independent prognostic factors. We compared the prognostic value of the molecular assays and standard TNM prognostic factors by multivariate analysis.

Adenoma↗
PubMed1994

Simple and sensitive quantitation method for mevalonic acid in plasma using gas chromatography/mass spectrometry.

The combination of gas chromatography and mass spectrometry using a polar capillary column and isobutane chemical ionization made it possible to determine mevalonic acid (MVA) as the lactone at subnanogram levels using 1 mL of plasma. The pretreatment procedure consisted of only three steps, namely lactonization, washing with chloroform and liquid/liquid extraction. This simple, rapid and sensitive method, having good precision and accuracy, is useful for evaluating the change of plasma MVA, which is well correlated with whole-body cholesterol biosynthesis.

Adult↗
PubMed1994

Electrophysiological evidence for formation of new corticorubral synapses associated with classical conditioning in the cat.

The present study was performed to clarify whether or not structural plasticity of synaptic connections underlies classical conditioning mediated by the red nucleus (RN) in the cat. Conditioned forelimb flexion is established by pairing electrical conditioned stimuli (CS), applied to corticorubral fibers at the cerebral peduncle (CP), with a forelimb skin shock (the unconditioned stimulus, US), but not by applying the CS alone or by pairing the CS and US at random intervals. In our previous study, it was shown that the firing probability of rubrospinal neurons (RN neurons) in response to the CS was well correlated with acquisition of the conditioned forelimb flexion and that the primary site of neural change underlying establishment of the conditioned forelimb flexion was suggested to be at corticorubral synapses. In the present study, we investigated corticorubral excitatory postsynaptic potentials evoked by CP stimulation (CP-EPSPs), in order to identify the neuronal mechanism underlying establishment of classical conditioning. In normal cats, CP-EPSPs had a typical slow-rising phase, which has been attributed to the distal location of corticorubral synapses on the dendrites of RN neurons. In contrast, in animals that received paired conditioning, subsequent CP stimulation evoked potentials with a fast-rising time course. In control groups of cats that received CS alone, CS randomly paired with the US, or only the same surgical operations as the conditioned animals, most of the CP-EPSPs displayed slow-rising EPSPs that similar to those observed in normal cats. The mean time from onset to peak of the potentials in the conditioned animals was significantly shorter than that seen in other groups. Therefore, the appearance of a fast-rising potential correlates well with acquisition of the conditioned forelimb flexion. The amplitude of the fast-rising potential was gradually changed with stimulus intensity. It had a short onset latency following CP stimulation (0.9 ms), which was similar to that of the slow-rising EPSP in normal cats. It followed high-frequency stimulation up to 100 Hz. These results suggest that the newly appearing, fast-rising potential was a monosynaptically evoked EPSP. Fast-rising EPSPs were also induced by stimulation of the sensorimotor cortex (SM). Since the SM-EPSP was occluded by the CP-EPSP, the SM cortex is, at least in part, a likely source of fast-rising EPSPs. Fast-rising SM-EPSPs were also observed at the unitary level. The SM-EPSPs in the conditioned animals exhibited somatotopical representation in their cortical origin, as has been described in normal cats.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Right atrial pressure and forearm blood flow during prolonged exercise in a hot environment.

Right atrial pressure (RAP) at rest is known to be reduced by an increase in skin blood flow (SkBF) in a hot environment. However, there is no clear evidence that this is so during exercise. To clarify the effect of the increase in SkBF on RAP during exercise, we measured forearm blood flow (FBF) (as an index of SkBF) and RAP continuously using a Swan-Ganz catheter in five male volunteers exercising on a cycle ergometer at 60% of peak aerobic power for 50 min in a hot environment (30 degrees C, relative humidity 20%). Cardiac output increased from 5.5 +/- 0.2 l/min at rest to 17.9 +/- 1.2 l/min (mean +/- SE, P < 0.01) in the first 10 min of exercise and then remained steady until the end of exercise. FBF did not change significantly during the first 5 min, but then increased from 2.7 +/- 0.5 ml/100 ml per min at rest to 10.8 +/- 1.7 ml/100 ml per min (P < 0.001) by 25 min as pulmonary arterial blood temperature (Tb) rose from 37.0 +/- 0.1 degrees C to 38.1 +/- 0.1 degrees C (P < 0.001). FBF then reached a plateau, despite a continuing increase in Tb. RAP increased significantly from 4.3 +/- 0.8 to 7.6 +/- 1.2 mm Hg (P < 0.001) during the first 5 min of exercise and then gradually declined to 6.1 +/- 1.0 mm Hg by 25 min (P < 0.001 vs. 5 min) and further to 5.7 +/- 1.0 mm Hg by 50 min, a value not significantly higher than at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Immunohistochemical study on the infection of herpes simplex virus, human cytomegalovirus, and Epstein-Barr virus in secondary diffuse interstitial pneumonia.

We examined the infection of herpes simplex virus (HSV), human cytomegalovirus (HCMV), and Epstein-Barr virus (EBV) in 61 autopsy cases with secondary diffuse interstitial pneumonia (SDIP) by immunohistochemistry and compared our findings with those in 46 individuals without lung complications. There was no significant difference in positivity of HSV infection between SDIP cases (28 of 61; 45.9%) and the controls (24 of 46; 52.2%). However, HSV was more extensively distributed in the lungs of seven SDIP cases than in those of controls and proliferated to form inclusion bodies in host cells of 11 SDIP cases. Twenty-two (36.1%) and 19 (31.1%) SDIP cases were positive for HCMV and EBV, respectively, whereas all the 46 controls were negative for both viruses. Eighteen of 22 HCMV-positive cases contained classical inclusion bodies in host cells. Epstein-Barr virus was detected extensively in the lungs of seven SDIP patients, but no viral inclusion bodies were observed in host cells. These findings indicate that the herpes viruses replicate excessively in a considerable number of SDIP cases, but classical inclusion bodies are not always associated with viral infection in the lungs. Major infected cells of these viruses were alveolar lining pneumocytes and intra-alveolar cells. Herpes simplex virus and EBV were detected in leukocytes as well as in pneumocytes. In addition, compared with HCMV and HSV, EBV frequently multiplied in bronchial or bronchiolar epithelial cells. Preferential host cells for these types of herpes virus were somewhat different from one another.

Antigens, Viral↗
PubMed1994

Resolution of 4-(4-chlorobenzyl)-2-(hexahydro-1-methyl-1H-azepin-4yl)-1(2H)-phthalazi none enantiomers in plasma with frit-FAB LC-MS using a conalbumin column.

A new column-switching method for analysis of drug enantiomers in plasma has been developed with liquid chromatography-frit fast atom bombardment mass spectrometry in combination with a chiral resolution column, which consists of conalbumin (egg-white glycoprotein) immobilized on silica gel and can be used in the reversed-phase separation mode. This method makes it possible to inject a large volume of deproteinized plasma and obtain resolution of drug enantiomers with high sensitivity. The optimum mobile phase, including a non-volatile buffer such as phosphate buffer, for separation of drugs from a large amount of endogenous compounds can be used, because of inclusion of a trapping column with a desalting function. This method is very simple and rapid, and should be very powerful in studies requiring high-sensitivity analysis with chiral separation of drugs from biological samples such as plasma.

Chromatography, High Pressure Liquid↗
PubMed1994

Benign glandular peripheral nerve sheath tumor. A case report.

The glandular peripheral nerve sheath tumor is a rare variant of nerve sheath neoplasms in which the focally occurring glands are lined by cells showing divergent differentiation. The vast majority of the reported nerve sheath tumors harboring these glands have been malignant. We herein present a case of benign glandular peripheral nerve sheath tumor in a 43-year-old woman who had no evidence of von Recklinghausen's disease. Histologically, the tumor is composed of spindle cell component and collections of glandular component. The glandular component occupied the central two-thirds of the lesion and was lined by a single layer of nonciliated cuboidal or columnar cells. No mitotic figures were recognized in the spindle cell area. This spindle cell area had neurofibroma-like features rather than schwannoma. Many of the spindle cells had positive reaction products for S-100 protein. The glandular lining epithelium were positive for cytokeratins (CAM 5.2, AE1/AE3, PKK1) and EMA. Some epithelial cells were immunoreactive for CEA, chromogranin, somatostatin and Leu-7. These immunohistochemical findings support the neuroendocrine differentiation of the epithelial element from the schwannian component.

Adult↗