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K Yamazaki

Publications and source records attributed to K Yamazaki.

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

Observation of helicity-induced Alfvén eigenmodes in large-helical-device plasmas heated by neutral-beam injection.

The helicity-induced Alfvén eigenmodes (HAEs) with the toroidal mode number n=2 and 3 are observed for the first time in the Large Helical Device plasmas heated by neutral beam injection. The observed mode frequency is about 8 times higher than that of the observed toroidicity-induced Alfvén eigenmodes, and is proportional to the Alfvén velocity. The modes are excited when the ratio of the beam velocity to the Alfvén velocity exceeds about unity. The frequency lies just above the lower bound of the HAE gap in the plasma edge region of rho>0.7 (rho: normalized minor radius).

Journal Article↗
PubMed2003

Sawtooth oscillation in current-carrying plasma in the large helical device.

Sawtooth oscillations have been observed in current-carrying helical plasmas by using electron-cyclotron-emission diagnostics in the Large Helical Device. The plasma current, which is driven by neutral beam injection, reduces the beta threshold of the sawtooth oscillation. When the central q value is increased due to the plasma current, the core region crashes, and, when it is decreased, the edge region crashes annularly. Observed rapid mixture of the plasma in the limited region suggests that these sawtooth crashes are reconnection phenomena. Unlike previous experiments, no precursor oscillation has been observed.

Journal Article↗
PubMed2003

Cyclic tensile stretch loaded on bovine chondrocytes causes depolymerization of hyaluronan: involvement of reactive oxygen species.

OBJECTIVE: We have previously demonstrated that reactive oxygen species (ROS) are involved in cartilage degradation. Decreased size of hyaluronan (HA), the major macromolecule in synovial fluid, to which it imparts viscosity, is reported in patients with arthritis. The purpose of this study was to determine the alteration in the molecular weight range of HA as a result of mechanical deformation loaded on the chondrocytes, as well as the involvement of ROS in this action. METHODS: ROS were generated via the oxidation of hypoxanthine by xanthine oxidase. Cyclic tensile stretch was loaded using a vacuum-operated instrument. Levels of HA were measured using a sandwich enzyme-binding assay. Superoxide dismutase (SOD) activity and ROS were measured using water-soluble tetrazolium and a chemiluminescent probe, respectively. RESULTS: ROS depolymerized HA molecules. Cyclic tensile stretch depolymerized HA and induced ROS. SOD inhibited not only ROS induction but also HA depolymerization caused by the mechanical stress. CONCLUSION: ROS play an important role in mechanical stress-induced HA depolymerization.

Animals↗
PubMed2003

Effects of cilostazol on serum lipid concentrations and plasma fatty acid composition in type 2 diabetic patients with peripheral vascular disease.

Cilostazol is an anti-thrombotic and vasodilating agent, reported to have both anti-thrombotic and cerebral vasodilating effects. We investigated the effects of cilostazol on serum lipid concentrations and plasma fatty acid composition in type 2 diabetic patients with peripheral vascular disease. The serum concentrations of total cholesterol, triglycerides, high-density lipoprotein-cholesterol, lipoprotein (a), remnant-like particles-cholesterol, apolipoproteins, and plasma fatty acid composition were measured in 17 diabetic patients with peripheral vascular disease before and 1, 3, and 6 months after administration of cilostazol (200 mg/day). Serum triglyceride concentrations were significantly decreased after cilostazol (from 1.31+/-0.17 mmol/l to 0.86+/-0.07 mmol/l at 6 months, P<0.01). Plasma docosahexaenoic acid levels were significantly increased after cilostazol (4.11+/-0.26% to 4.94+/-0.26% at 6 months, P<0.01). Our findings show that cilostazol can induce some beneficial changes in serum lipid profile and plasma fatty acid composition.

Aged↗
PubMed2003

Porphyromonas gingivalis antigen preferentially stimulates T cells to express IL-17 but not receptor activator of NF-kappaB ligand in vitro.

Although T cells have been implicated in the pathogenesis and are considered to be central to both their progression and control of chronic inflammatory periodontal diseases, the precise contribution of T cells to tissue destruction has not been fully clarified. Recently, interleukin (IL)-17 and receptor activator of Nuclear factor kappaB NF-kappaB ligand (RANKL) have received much attention as a result of their proinflammatory and bone metabolic roles, respectively. We therefore investigated the effect of outer membrane protein (OMP) from Porphyromonas gingivalis (P. gingivalis) on the expression of IL-17 and RANKL in peripheral blood mononuclear cells (PBMCs) and compared these between gingivitis and periodontitis, which are representative of stable and progressive lesions, respectively. The in situ expression of these molecules was also examined. P. gingivalis OMP stimulated PBMCs to express IL-17 at both the mRNA and protein level. Although the mean expression of mRNA was not different between the two groups, the mean level of IL-17 in the culture supernatants was higher in gingivitis patients than in periodontitis patients. However, the frequency of IL-17-positive samples was higher in the periodontitis patients. This stimulatory effect was not evident for RANKL expression in either periodontitis or gingivitis patients. In gingival tissue samples, IL-17 mRNA was detected in gingivitis more frequently than in periodontitis. The expression of RANKL mRNA was much lower than that of IL-17 in terms of both level and frequency. These results suggest that IL-17 but not RANKL may be involved in the pathogenesis of periodontal diseases. However, there may be negative regulatory mechanisms for IL-17 in gingivitis.

Adult↗
PubMed2003

Chemical signalling in mice.

Odours play a critical role in the behaviour and physiology of many species. For mice and probably many other species, including humans, an individual's olfactory identity (its odourtype) is coded in part by a pattern of volatile compounds that is regulated by genes in the major histocompatibility complex, a string of linked genes that is intimately involved in immune function. The mouse olfactory system is exquisitely sensitive to minute variations in odourtypes. Layered within these chemical signals of individuality is information on the age and health status of the mouse. In the case of age, it appears that information is coded based on a pattern of volatile metabolites; we do not know how a mouse detects, for example, the presence of a viral infection in volatiles from an infected mouse. This chemical information serves to regulate mate choice and other aspects of social behaviour.

Aging↗
PubMed2003

Increased cyclin D1 expression in cancer of the ampulla of Vater: relevance to nuclear beta catenin accumulation and k-ras gene mutation.

AIMS: Several studies have reported that dysregulation of beta catenin or k-ras mutation promotes cyclin D1 expression. This study investigated the relation between cyclin D1 expression and clinicopathological parameters in carcinoma of the ampulla of Vater (CAV), and also assessed the relation between increased cyclin D1 expression and beta catenin/k-ras status in this series. METHODS: Thirty CAVs were evaluated for cyclin D1 expression by immunohistochemistry in relation to patient clinicopathological features. Aberrant beta catenin expression and k-ras mutation were also investigated by immunostaining and direct sequencing, and related to cyclin D1 expression. RESULTS: Increased cyclin D1 expression was seen in 17 of 30 CAVs and was significantly correlated with tumour cell proliferation and disease free survival time (p = 0.018, p = 0.018, respectively). Nuclear accumulation of beta catenin was found in nine of 30 cases, including four cases with missense mutations in exon 3 of CTNNB-1, and was significantly correlated with increased cyclin D1 expression (p = 0.003). k-ras gene mutation was detected in 12 of 30 cases, and was also significantly correlated with increased cyclin D1 expression (p = 0.026). Overall, 14 of 17 CAVs with increased cyclin D1 expression showed nuclear accumulation of beta catenin and/or k-ras mutation. CONCLUSIONS: Increased cyclin D1 expression appears to be associated with tumour proliferation and poorer clinical outcome in CAV. It is also associated with both aberrant beta catenin expression and k-ras mutation. These results are consistent with the in vitro data that cyclin D1 can be transactivated by activated beta catenin-T cell factor/LEF and k-ras pathways.

Aged↗
PubMed2003

Single-nucleotide polymorphism in the CD14 promoter and periodontal disease expression in a Japanese population.

It has been reported that there is a relationship between a single-nucleotide polymorphism (SNP) in the promoter region of the CD14 gene at position -159 (C-->T) and infectious diseases. The aim of the present study was to test the hypthesis that expression of this SNP correlates with periodontal disease in a Japanese population. The CD14 genotype was determined in 163 subjects with periodontitis and in 104 age- and gender-matched control subjects without periodontitis. The genotype distribution and allele frequency within the periodontitis patients were not significantly different from those of control subjects. There was, however, a significant difference in the genotype distribution between young patients (< 35 yrs) and older patients (>/==" BORDER="0"> 35 yrs). These findings suggest that CD14 -159C/T polymorphism is not related to the development of periodontitis in a Japanese population, but that, within the periodontitis subjects, expression of the SNP may be related to early disease activity.

Adult↗
PubMed2003

T cell regulation of the immune response to infection in periodontal diseases.

Although T cells have been implicated in the pathogenesis and are considered to be central both in progression and control of the chronic inflammatory periodontal diseases, the precise contribution of T cells to the regulation of tissue destruction has not been fully elucidated. Current dogma suggests that immunity to infection is controlled by distinct T helper 1 (Th1) and T helper 2 (Th2) subsets of T cells classified on the basis of their cytokine profile. Further, a subset of T cells with immunosuppressive function and cytokine profile distinct from Th1 or Th2 has been described and designated as regulatory T cells. Although these regulatory T cells have been considered to maintain self-tolerance resulting in the suppression of auto-immune responses, recent data suggest that these cells may also play a role in preventing infection-induced immunopathology. In this review, the role of functional and regulatory T cells in chronic inflammatory periodontal diseases will be summarized. This should not only provide an insight into the relationship between the immune response to periodontopathic bacteria and disease but should also highlight areas of development for potentially new therapeutic modalities.

Animals↗
PubMed2003

A case of splenic lymphoma with marked diffuse nodular fibrosis and calcification, complicated with severe autoimmune hemolytic anemia.

A splenic lymphoma, possibly of a splenic marginal zone lymphoma, marked by small nodular splenic calcified fibrosis and complicated by intractable autoimmune hemolytic anemia, was studied by immunohistochemical, molecular genetic, and ultrastructural analyses. The patient was a 57-year-old Japanese man who had moderate splenomegaly, and who had undergone splenectomy for improvement of severe autoimmune hemolytic anemia and to rule out malignancy in the spleen. In the resected spleen, proliferative atypical lymphoid cells were observed both in the red and white pulp with diminished germinal centers and irregularly widened marginal zones with peculiar dimorphic pattern. Ultrastructural study revealed no hairy cells or villous lymphocytes. Diffuse nodular hyalinous fibrosis surrounding the small arterioles in the white pulp overlapped with frequent calcification was a unique histologic feature in this case. Degenerative connective tissue, extracellular matrix, or collagen fibers surrounding the arterial sheath in the white pulp caused by some immunological abnormalities associated with this splenic lymphoma could be assumed to be the predisposing factor for this excessive fibrosis and dystrophic calcification in the spleen.

Anemia, Hemolytic, Autoimmune↗
PubMed2003

[Acute pulmonary embolism performed embolectomy under percutaneous cardiopulmonary support successfully after lung cancer operation].

We have experienced a case of acute pulmonary embolism after lung cancer operation. The case was a 74-year-old male. He underwent left upper lobectomy due to squamous cell carcinoma. He fell into shock state suddenly on the 6th day postoperatively. We diagnosted acute pulmonary embolism, performed urgent embolectomy under percutaneous cardiopulmonary support (PCPS). Postoperative course was smooth, and he has returned to normal daily life. Urgent diagnosis and management are indispensable for acute pulmonary embolism after lung cancer operation from the aspect of residual among of pulmonary vascular bed.

Acute Disease↗
PubMed2003

A seminal vesicle cyst complicated with a tumor like nodular mass of benign proliferating prostatic tissue: a case report with ultrastructural and immunohistochemical studies.

We report a seminal vesicle cyst complicated with a tumor-like nodular mass of benign proliferating prostatic tissue. The patient was a 53-year-old Japanese man. A cyst of approximately 4.5 cm in diameter was discovered at the left seminal vesicle area. In the inner part of the cyst, a papillary nodular mass of 0.7 cm in diameter was seen. Under the clinical diagnosis of a seminal vesicle cyst with a tumorous mural nodule, the patient underwent resection of the seminal vesicle cyst to rule out the possibility that the nodular mass in the cyst was a neoplasm of an especially malignant nature. Microscopic examination of the excised specimen revealed a small dome-like nodular mass on the luminal surface of the cyst consisting of nodular proliferation of benign tubular gland tissue with various configurations. Conventional histologic, immunohistochemical, and ultrastructural analysis showed the proliferating cells in the nodular mass consisted of the benign prostate type. It is extremely important to differentiate between a benign proliferation and a malignant one, when the nodular mass is found in the seminal vesicle cyst.

Alkaline Phosphatase↗
PubMed2003

A unique pancreatic ductal adenocarcinoma with carcinosarcomatous histology, immunohistochemical distribution of hCG-beta, and the elevation of serum alpha-feto-protein.

Pancreatic undifferentiated carcinomas with a neoplastic mesenchymal component (carcinosarcoma) have not been well described to date. The author experienced an autopsy case of a unique pancreatic ductal adenocarcinoma with carcinosarcomatous histology. The patient was a 90 year old Japanese male who died of cahexia with generalized tumor extension. Post-mortem examinations revealed some distinctive or representative components discerned in the tumor tissue. One was the well differentiated ductal adenocarcinoma. The second and the major finding was undifferentiated short spindle shaped or small round sarcomatous cells, which lacked an epithelial nature but showed positivity for CD10+, CD56+, Ki67++, p53++, and were focally positive for Desmin and vimentin. These two components were mixed and constituted the histology of the carcinosarcoma. In another area, anaplastic, large, pleomorphic tumor cells showed the focal immunohistochemical distribution of alpha-feto-protein and human chorionic gonadotropin. An ultrastructural study revealed adenocarcinoma cells with apical mucin secreting granules and well developed ductal differentiation, whereas undifferentiated sarcomatous cells showed primitive fibroblastic or mesenchymal characters without specific differentiation. Conclusively these findings suggested that this well differentiated adenocarcinoma gradually enlarged, accumulated genetic alternations, and then transformed into large and undifferentiated tumor cells, rapidly growing small sarcomatous cells, and a histology of carcinosarcoma.

Adenocarcinoma↗
PubMed2002

Inhibition of proliferation and induction of differentiation of glioma cells with Datura stramonium agglutinin.

We found that a lectin, Datura stramonium agglutinin, induced irreversible differentiation in C6 glioma cells. The differentiated cells had long processes, a low rate of proliferation and a high content of glial fibrillary acidic protein. When the medium was replaced with Datura stramonium agglutinin-free medium after 1 h, cell proliferation continued to be inhibited. Experiments with several other lectins indicated that both recognition of linear N-acetyllactosamine repeats and recognition of multiantennary units of cell-surface glycans were required for the inhibition of C6 proliferation. Proliferation of four human glial tumour cells was also inhibited by Datura stramonium agglutinin. Further, these differentiated human glial tumour cells had long processes and a high content of glial fibrillary acidic protein similar to differentiated C6 glioma cells. Taken together, these observations suggest that Datura stramonium agglutinin may be useful as a new therapy for treating glioma without side effects.

Agglutinins↗
PubMed2002

N-acetylgalactosaminyl transferase-3 is a potential new marker for non-small cell lung cancers.

N-acetylgalactosaminyl transferase-3 (GalNAc-T3) is an enzyme involved in the initial glycosylation of mucin-type O-linked proteins. In the present study, we used immunohistochemistry to examine GalNAc-T3 expression in 215 surgically resected non-small cell lung cancers. We analysed the biological and clinical importance of GalNAc-T3 expression, especially with regard to its potential as a prognostic factor. We found that normal bronchial epithelial cells, bronchial gland cells, and alveolar pneumocytes showed cytoplasmic immunostaining for GalNAc-T3. Low expression of GalNAc-T3, observed in 93 of 215 tumours (43.4%), was found more frequently in tumours from smokers than those from nonsmokers (P=0.001), in squamous cell carcinomas than nonsquamous cell carcinomas (P<0.0001), and in moderately and poorly differentiated tumours than well differentiated tumours (P=0.0002). Multivariate logistic regression analysis showed that an association of low GalNAc-T3 expression with squamous cell carcinomas was the only one significant relationship of GalNAc-T3 expression with various factors (P<0.0001). Moreover, tumours losing GalNAc-T3 expression had a significantly higher Ki-67 labelling index than tumours retaining GalNAc-T3 expression (P=0.0003). Patients with low GalNAc-T3 expression survived a significantly shorter time than patients with high GalNAc-T3 expression in 103 pStage I non-small cell lung cancers (5-year survival rates, 58% and 78%, respectively; P=0.02 by log-rank test) as well as in 61 pStage I nonsquamous cell carcinomas (5-year survival rates, 63% and 85%, respectively; P=0.03). Low GalNAc-T3 expression was an unfavourable prognostic factor in pStage I non-small cell lung cancers (hazards ratio, 2.04; P=0.03), and in pStage I nonsquamous cell carcinomas (hazards ratio, 2.70; P=0.03). These results suggest that GalNAc-T3 is a new marker of non-small cell lung cancers with specificity for histology and prognosis.

Aged↗
PubMed2002

Laparoscopic hepatectomy for extrahepatic growing tumor. Surgical strategy based on extrahepatic growing index.

BACKGROUND: This article describes the operative procedures, varying difficulties, and required instrumentation for performing laparoscopic hepatectomy (LH) on the basis of a lesion's extrahepatic growing (EG) index, as calculated by computed tomography (CT). METHODS: Laparoscopic partial hepatectomy cases were divided into the following two groups: an EG tumor group (n = 11) and an intrahepatic tumor group (n = 8). The surgical procedures, operative results, and laparoscopic instrumentation for these two groups were compared based on the EG index (/cm2; maximum diameter of tumor pedicle/maximum vertical diameter of tumor/area of the tumor). RESULTS: The mean operative time was significantly shorter and the mean blood loss was significantly less in the EG tumor group than in the intrahepatic tumor group. In addition, in the EG tumor group, there were significant differences in mean operative time and mean blood loss related to the values associated with the EG index (p <0.05, P <0.01). The selection of laparoscopic instruments was based on the EG index, as follows: (a) lesions with an EG index >5/cm2 underwent resection in combination with a microwave tissue coagulator and an ultrasonic surgical aspirator (13 cases, including intrahepatic tumor cases); (b) lesions with an EG index of 5-15/cm2 underwent resection in combination with a microwave tissue coagulator and laparosonic coagulating shears (four cases); (c) lesions with an EG index <%15/cm2 underwent resection with a laparoscopic linear stapler (two cases). CONCLUSION: Our preliminary experience leads us to believe that it is useful to calculate the EG index by CT scan before formulating the technical strategy for a subsequent LH procedure.

Bile Duct Neoplasms↗
PubMed2002

Island dynamics in the large-helical-device plasmas.

In the Large Helical Device plasma discharges, the size of an externally imposed island with mode number ( n/m = 1/1) decreases substantially when the plasma is collisionless ( nu(*)< approximately 1) and the beta is finite ( > approximately 0.1%) at the island location. For the collisional plasmas with finite beta, on the other hand, the size of the island increases. However, there is a threshold in terms of the vacuum island size below which the island enlargement is not seen.

Journal Article↗