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Biomedical subjects

Yasuhiro Tanaka

Publications and source records attributed to Yasuhiro Tanaka.

At least 55 records · Page 3Linked to original sources
PubMed2003

Weekly paclitaxel for a patient with advanced gastric cancer.

A 56-year-old woman diagnosed with gastric cancer was admitted to our hospital for operation on May 15, 2001. The operation was performed on May 23. The tumor formed a large mass from the antrum to the head of the pancreas, and cancer cells were detected in the ascitic fluid microscopically. During the operation, resection was impossible, and so 100 mg of cisplatin (CDDP) was infused into the abdominal cavity. After the operation, she experienced continuous nausea and there was a discharge of 1200-1600 ml of digestive fluid per day from her nasogastric tube. On July 17, a new regimen, of 4-week courses of chemotherapy, with weekly administrations of 65 mg/m2 of paclitaxel, along with premedication for 3 weeks, followed by 1 week of rest, was started. After the first of these 4-week courses, the discharge from her nasogastric tube decreased to 200-600 ml per day, and the tube was removed 78 days after insertion. Oral intake of food increased smoothly, and she was discharged on September 14. After another, short, hospitalization, she was discharged on October 20, and she has been coming to our outpatient clinic once a week. After paclitaxel was started, gastric fiberscopy and computed tomography (CT) scan showed reduction of the tumor. Of special note was the disappearance of a scitic fluid after two courses, rated as a "partial response" (Japanese classification). There was a decrease in hemoglobin, but neither leukocytopenia nor a decrease in platelets was found. Neuropathy was slight and no treatment was needed. Now, after 1 year, 11 courses of chemotherapy have been administered at the outpatient clinic. These results suggest weekly administration of paclitaxel to be a promising treatment for advanced gastric cancer with peritoneal dissemination. The therapeutic efficacy should be confirmed by further clinical trials.

Adenocarcinoma↗
PubMed2003

Application of cast iron-platinum keeper to a collapsible denture for a patient with constricted oral opening: a clinical report.

Insertion of a denture is especially difficult for patents with a constricted oral opening. This report describes the fabrication of a collapsible removable partial denture with a cast iron-platinum attachment for a partially edentulous woman with a constricted oral opening resulting from rheumatoid arthritis and a craniotomy for a subarachnoid hemorrhage.

Aged↗
PubMed2003

High resolution transmission electron microscopy of age-hardenable Au-Cu-Zn alloys for dental applications.

Microstructures of age-hardenable AuCu-Zn pseudobinary alloys for dental applications were studied by means of high resolution transmission electron microscopic (HRTEM) observation and X-ray diffraction study. HRTEM study revealed that the appearance frequency of antiphase boundaries (APBs) per unit volume of the AuCu II superstructure effectively increased by Zn addition to AuCu, which may be the reason for that high hardness was maintained for a long time in AuCu-Zn alloys. The disordered APBs zone in the AuCu II superstructure had wavy characteristics and fluctuated within regular range. With increasing Zn content in AuCu-Zn alloys, the fluctuation range of APBs' width became narrower, thus random APBs' spacing and irregular APBs' shape of AuCu II superstructure changed to comparatively regular APBs' spacing and shape. Due to the APBs' wavy characteristics, spacing between successive APBs, M, was not constant but scattered, and the magnitude of the scattering of M value decreased with increasing Zn content. By Zn addition to AuCu, phase transformation from a disordered alpha phase to AuCu II phase was greatly accelerated, which made it possible for the AuCu-Zn alloy to have excellent age-hardenability at relatively low temperature like intraoral temperature.

Alloys↗
PubMed2003

Factors affecting the optical properties of Pd-free Au-Pt-based dental alloys.

The optical properties of experimental Au-Pt-based alloys containing a small amount of In, Sn, and Zn were investigated by spectrophotometric colorimetry to extract factors affecting color of Au-Pt-based high-karat dental alloys. It was found that the optical properties of Au-Pt-based alloys are strongly affected by the number of valence electrons per atom in an alloy, namely, the electron:atom ratio, e/a. That is, by increasing the e/a-value, activities of reflection in the long-wavelength range and absorption in the short-wavelength range in the visible spectrum apparently increased. As a result, the maximum slope of the spectral reflectance curve at the absorption edge, which is located near 515 nm (approximately 2.4 eV), apparently increased with e/a-value. Due to this effect, the b*-coordinate (yellow-blue) in the CIELAB color space considerably increased and the a*-coordinate (red-green) slightly increased with e/a-value. The addition of a third element with a higher number of valence electrons to the binary Au-Pt alloy is, therefore, effective in giving a gold tinge to the parent Au-Pt alloy. This information may be useful in controlling the color of Au-Pt-based dental alloys.

Journal Article↗
PubMed2003

Immunotherapy of spontaneous mammary carcinoma with fusions of dendritic cells and mucin 1-positive carcinoma cells.

The tumour-associated antigen mucin 1 (MUC1) is a multifunctional protein involved in protection of mucous membranes, signal transduction, and modulation of the immune system. More than 70% of cancers overexpress MUC1, making MUC1 a potential target for immunotherapy. In the present study, MUC1 transgenic mice were crossed with syngeneic strains that express the polyomavirus middle-T oncogene (PyMT) driven by the mouse mammary tumour virus promoter long-terminal repeat (MMTV-LTR). The resultant breed (MMT mice) developed spontaneous MUC1-expressing mammary carcinomas with 100% penetrance at 8-15 weeks of age. As found in human breast cancer, the mammary carcinoma in MMT mice arose in multiple stages. Immunization with fusions of dendritic cells and MUC1-positive tumour cells (FC/MUC1) induced MUC1-specific immune responses that blocked or delayed the development of spontaneous breast carcinomas. In contrast, there was no delay of tumour development in MMT mice immunized with irradiated MC38/MUC1 tumour cells. The efficacy of fusion cells was closely correlated with the timing of initial immunization. Immunization with FC/MUC1 initiated in MMT mice at < 1, 1-2 and 2-3 months of age rendered 33, 5 and 0% of mice free of tumour, respectively, up to 6 months. Whereas mice immunized in the later stage of tumour development succumbed to their disease, immunization resulted in control of tumour progression and prolongation of life. These results indicate that immunization with FC/MUC1 can generate an anti-MUC1 response that is sufficient to delay the development of spontaneous mammary carcinomas and control tumour progression in MMT mice.

Animals↗
PubMed2003

Effectiveness of angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker on atrial natriuretic peptide.

The aim of this study was to evaluate the effectiveness of an angiotensin-converting enzyne inhibitor (ACEI, quinapril) or angiotensin II receptor blocker (ARB, candesartan) on atrial natriuretic peptide (ANP) activity in rats with hypertension induced by nitric oxide (NO) inhibition. ACEI and ARB have a number of pharmacologic effects, including blood pressure reduction, myocardial preservation, and an unknown effect in the circulation. The changes in ANP in NO inhibitor-induced hypertensive rats were evaluated in order to elucidate the interaction between ANP and NO in the regulation of blood pressure. Thirty-six rats were divided into 4 groups and administered the experimental agents for 8 weeks: group CONTROL was given regular food (n=9), group N(G)-nitro-L-arginine (L-NNA) was administered L-NNA (25 mg. kg(-1). day(-1), n=9), group ACEI was administered L-NNA and quinapril (10 mg. kg(-1). day(-1), n=9), and group ARB was administered L-NNA and candesartan (10 mg. kg(-1). day(-1), n=9). Blood pressure, plasma ANP, atrial ANP, ANP mRNA, and ANP granules were measured. A significant elevation in blood pressure was observed in group L-NNA. However, there were no increases in plasma ANP (L-NNA: 138.8+/-64.4, CONTROL: 86.7+/-36.4), ANP mRNA (L-NNA: 2.2+/-1.0, CONTROL: 1.7+/-0.5) or ANP granules (L-NNA: 61.1+/-10.2, CONTROL: 64.5+/-8.5). No increase in blood pressure was seen in groups ACEI and ARB. However, plasma ANP (ACEI: 1,392.3+/-1,034.4, ARB: 1,142.8+/-667.3), ANP mRNA (ACEI: 52.8+/-29.1, ARB: 42.9+/-21.2), and ANP granules (ACEI: 122.5+/-23.4, ARB: 136.3+/-33.2) increased significantly. NO inhibitor-induced hypertension caused no changes in ANP concentrations. However, the ACEI and ARB had a direct effect on the induction of ANP secretion. The findings suggest that ANP secretion is directly effected by ACEI and ARB, which seems to play a key role in lowering blood pressure, relieving heart failure symptoms, and preserving the myocardium.

Angiotensin Receptor Antagonists↗
PubMed2003

[Congenital middle ear cholesteatoma: experience in 48 cases].

We studied 48 patients (48 ears) with congenital cholesteatoma who underwent surgery at our department from 1979 to 2000, and investigated symptoms at initial onset, tympanic membrane findings, cholesteatoma configuration and site, type of surgical procedure, and surgical outcome. Patients were from 2 to 62 years old (mean: 16.7 years), with 60.4% aged 15 years or younger. The symptom at initial onset was hearing loss in most (58.2%). Hearing loss was the main symptom in all with open type cholesteatoma, and most of these patients had normal tympanic membrane findings. The cholesteatoma was located mainly in the superior posterior portion of the tympanic cavity in many patients. The site of involvement was the tympanic cavity in 12 (25.0%), mastoid cavity in 2 (4.2%) and the petrous apex in 1 (2.1%). In many of (31 ears, 64.6%), the cholesteatoma was advanced and extended from the tympanic cavity to the mastoid antrum. For 23 of the 48 ears, treatment was completed in one operation. The remaining 25 ears required staged surgery. Loss of the structure of the upper part of the stapes was seen in 58.3% of patients, so most underwent type IV ossiculoplasty, with types III and I next most common.

Adolescent↗
PubMed2003

[Weekly administration of paclitaxel with a short course of premedication for advanced or recurrent gastric cancer].

Weekly administration of paclitaxel with a short course of premedication was performed for 8 patients with advanced or recurrent gastric cancer. In this regimen, 500 ml of physiological saline with vitamins was administered in a 3-hour infusion. After 30 minutes of infusion, dexamethasone 10 mg, chlorpheniramine maleate 5 mg, famotidine 20 mg and ramosetron hydrochloride 0.3 mg were administered intravenously. After 30 more minutes of infusion, paclitaxel at a dose of 65 mg/m2 was admixed in the residual normal physiological saline and administered over 2 hours. Administration was continued for 3 weeks with a 1 week rest. Though the partial response rate was 25%, clinical symptoms improved in all patients. Moreover, both hematological and non-hematological toxicities were mild. Weekly administration of paclitaxel with a short course of premedication is an effective and well-tolerated method for patients with advanced or recurrent gastric cancer.

Aged↗
PubMed2002

A new approach to evaluating occlusal support by analyzing the center of the bite force.

The aim of this study was to create a standard for occlusal support in the diagnosis and evaluation of prosthetic treatment. In experimental occlusion, the maximal bite force of eight normal dentates was measured by pressure-sensitive film over the whole dentition using splints divided into nine pieces. The occlusal contact was altered by exchanging splint pieces according to the shortened dental arch concept. The occlusal load center (OLC) was located on a graph set up with reference to the size of the individual dental arch. The occlusal supporting index (SI) and the rehabilitation index (RI) were calculated from the locations of the OLC corresponding to each occlusal contact. Differences in numbers and distribution of occlusal stops could clearly be distinguished by the location of the OLC. Though the SI showed a strong positive correlation with maximal bite force, it is proposed that the number of occlusal stops, or occlusal units, provides the most effective index for quantitative parameters of occlusal support in clinical use. From the standpoint of bite force, analysis of the RI is suggested as a useful method of objectively evaluating the recovery of occlusal support with prosthetic treatment.

Adult↗
PubMed2002

The cbs mutant strain of Rhodococcus erythropolis KA2-5-1 expresses high levels of Dsz enzymes in the presence of sulfate.

Two mutants of the dibenzothiophene-desulfurizing Rhodococcus erythropolis KA2-5-1, strains MS51 and MS316, which express a high level of desulfurizing activity in the presence of sulfate, were isolated using the transposome technique. The level of dibenzothiophene-desulfurization by cell-free extracts prepared from mutants MS51 and MS316 grown on sulfate was about five-fold higher than that by cell-free extracts of the wild-type. This result was consistent with results of Western-blot analysis using antisera specific for DszA, DszB and DszC, the enzymes involved in the desulfurization of dibenzothiophene. Gene analysis of the mutants revealed that the same gene was disrupted in mutants MS51 and MS316 and that the transposon-inserted gene in these strains was the gene for cystathionine beta-synthase, cbs. The cbs mutants also expressed high levels of Dsz enzymes when methionine was used as the sole source of sulfur.

Biodegradation, Environmental↗
PubMed2002

Immunization against murine multiple myeloma with fusions of dendritic and plasmacytoma cells is potentiated by interleukin 12.

Fusions of cancer cells and dendritic cells (DCs) are effective in the treatment of animal tumor models and patients with metastatic renal carcinoma. In this study, we have fused DCs with mouse 4TOO plasmacytoma cells. The results demonstrate that vaccination of mice with the fusion cells (FC/4TOO) is associated with induction of antitumor humoral and cytotoxic T lymphocyte (CTL) responses. Immunization with FC/4TOO cells protected mice against tumor challenge. In addition, treatment of established multiple myeloma with FC/4TOO cells was associated with prolongation of survival but not with eradication of disease. As interleukin (IL)-12 potentiates the induction of immune responses, recombinant mouse IL-12 was administered with the FC/4TOO vaccine. Treatment of mice with FC/4TOO and IL-12 was associated with increased CTL activity and T-cell proliferation responses. Treatment with FC/4TOO and IL-12 also resulted in eradication of established disease. These findings demonstrate that immunization with FC/4TOO fusion cells and IL-12 potentiates antitumor immunity and the treatment of murine multiple myeloma.

Animals↗
PubMed2002

The kinetics of in vivo priming of CD4 and CD8 T cells by dendritic/tumor fusion cells in MUC1-transgenic mice.

Previous work has demonstrated that dendritic/tumor fusion cells induce potent antitumor immune responses in vivo and in vitro. However, little is known about the migration and homing of fusion cells after s.c. injection or the kinetics of CD4+ and CD8+ T cell activation. In the present study, fluorescence-labeled dendritic/MUC1-positive tumor fusion cells (FC/MUC1) were injected s.c. into MUC1-transgenic mice. The FC/MUC1 migrated to draining lymph nodes and were closely associated with T cells in a pattern comparable with that of unfused dendritic cells. Immunization of MUC1-transgenic mice with FC/MUC1 resulted in proliferation of T cells and induced MUC1-specific CD8+ CTL. Moreover, CD4+ T cells activated by FC/MUC1 were multifunctional effectors that produced IL-2, IFN-gamma, IL-4, and IL-10. These findings indicate that both CD4+ and CD8+ T cells can be primed in vivo by FC/MUC1 immunization.

Adoptive Transfer↗
PubMed2002

Recombinant Rhodococcus sp. strain T09 can desulfurize DBT in the presence of inorganic sulfate.

The putative Rhodococcus rrn promoter region was cloned from the benzothiophene desulfurizing Rhodococcus sp. strain T09, and the dibenzothiophene desulfurizing gene, dsz, was expressed under the control of the putative rrn promoter in the strain T09 using a Rhodococcus-E.coli shuttle vector. Strain T09 harboring the expression vector, pNT, could desulfurize dibenzothiophene in the presence of inorganic sulfate, methionine, or cysteine, while the Dsz phenotype was completely repressed in recombinant cells carrying the gene under the control of the native dsz promoter under the same conditions. Among the sulfur sources examined, no intermediates were detected and only the final desulfurized product, 2-hydroxy-biphenyl, was produced using ammonium sulfate as the sulfur source.

Cloning, Molecular↗
PubMed2002

Ordering behaviors and age-hardening in experimental AuCu-Zn pseudobinary alloys for dental applications.

Age-hardening mechanisms and related ordering behaviors of the experimental (AuCu)(1-x)Zn(x) alloys with x < or = 0.2 were investigated for dental applications. The addition of Zn to equiatomic AuCu greatly increased the age-hardening rate and delayed overaging. It was suggested that the quenched-in excess vacancies were greatly related to the age-hardening rate in the AuCu-Zn pseudobinary alloys. In these alloys, the hardness became maximum during the very initial stage of ordering, and with the development of ordered phase, the hardness began to decrease. Transmission electron microscopy revealed that the age-hardening of AuCu-Zn pseudobinary alloys is caused by lattice distortion that occurred during the very early stage of atomic ordering. The addition of Zn to AuCu effectively increased the density of antiphase boundaries per unit volume of the AuCu II superstructure. This is suggested to be the main cause for the retardation of the overaging in the alloys containing Zn of 5 at% or more. This pronounced effect of Zn addition to AuCu alloy on its age-hardening characteristics may be advantageous for obtaining stable mechanical properties of dental casting gold alloys.

Copper↗
PubMed2002

Effects of Zn addition to AuCu on age-hardening behaviors at intraoral temperature.

The effect of Zn addition to AuCu on the age-hardening rate at the intraoral temperature was investigated to find out the proper condition for high age-hardening rate. The increase in hardness of Zn-added alloys during aging at 37 degrees C was due to the atomic ordering. With an increase in Zn concentration, hardness of a sample under the as-quenched condition decreased, but the age-hardening rate obviously increased. When Zn content was fixed, a higher solution treatment temperature was more effective for the age-hardening at 37 degrees C. It was suggested that the formation energy of a vacancy considerably decreased with an increase in Zn content. It is reasonable to consider that the amount of quenched-in excess vacancies are markedly increased with an increase in Zn content when the solution treatment temperature was fixed. By transmission electron microscopic observations, it was revealed that the formation of the AuCu II superstructure contributed to the age-hardening at 37 degrees C in the high zinc content alloy.

Journal Article↗
PubMed2002

Application of cast magnetic attachments to sectional complete dentures for a patient with microstomia: a clinical report.

Patients with microstomia who must wear removable dental prostheses often state that they are unable to insert or remove the prosthesis because of the constricted opening of the oral cavity. This article presents a cast iron-platinum magnetic attachment system applied to sectional collapsed complete dentures for an edentulous patient with microstomia. With the use of lingual and palatal midline hinges and a cast iron-platinum magnetic attachment, the sectional prosthesis was successfully and easily inserted and provided adequate function in the patient's mouth.

Aged↗
PubMed2002

Spontaneous necrosis of hepatocellular carcinoma: a case report.

BACKGROUND: Spontaneous regression of a malignant tumor is a rare phenomenon. So far, 13 cases of spontaneous regression of hepatocellular carcinoma (HCC) have been described in the English literature. We report a case of HCC, with spontaneous complete necrosis demonstrated by histological examination. METHODS: A 73-year-old male was admitted to our hospital complaining of general fatigue. CT and US revealed a huge mass measuring 9.5 cm at the left lobe. Angiographies showed hypovascular tumor stains. The levels of alpha-fetoprotein (AFP) and PIVKA-2 on admission were high, at 55 ng/ml and 62,300 mAU/ml, respectively. We diagnosed hypovascular HCC and performed a left lobectomy on October 16, 2000. RESULTS: In the histological examination, no viable cells were found. The levels of AFP and PIVKA-2 had already decreased to 14 ng/ml and 1,420 mAU/ml, before laparotomy. CONCLUSION: Changes in tumor markers and histological findings reveal that this phenomenon occurred without specific treatment.

Aged↗