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Biomedical subjects

K Nakano

Publications and source records attributed to K Nakano.

At least 37 records · Page 2Linked to original sources
PubMed2003

Gene cloning, expression, and crystallization of a thermostable exo-inulinase from Geobacillus stearothermophilus KP1289.

The gene ( inuA) encoding exo-inulinase (EC 3.2.1.80) was cloned from the thermophilic Geobacillus stearothermophilus ( Bacillus stearothermophilus) KP 1289 growing at between 41 degrees C and 69 degrees C. The inuA gene consisted of 1,482 bp encoding a protein of 493 amino acids. The deduced polypeptide of molecular mass ( M) 56,744 Da showed strong sequence similarity to Pseudomonas mucidolens exo-inulinase, Bacillus subtilis levanase, Paenibacillus polymyxa ( Bacillus polymyxa) fructosyltransferase, and so on, indicating that the enzyme belonged to glycosyl hydrolase family 32. The M of the purified exo-inulinase, expressed in Escherichia coli HB101, was estimated as approximately 54,000 Da by both SDS-PAGE and gel filtration. These results suggested that the active form of the enzyme is a monomer. The enzyme was active between 30 and 75 degrees C with an optimum at 60 degrees C. The properties were identical to those of the native enzyme. Additionally, for the first time for a prokaryotic GH32 protein, crystals of the recombinant enzyme were obtained.

Amino Acid Sequence↗
PubMed2003

Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded vMIP-I and vMIP-II induce signal transduction and chemotaxis in monocytic cells.

Kaposi's sarcoma-associated herpesvirus (KSHV)/ Human herpesvirus 8 encodes three chemokines, which are called viral macrophage inflammatory protein (vMIP)-I, -II, and -III. Here, we expressed the KSHV vMIP-I and vMIP-II proteins and analyzed their biological functions. Both vMIP-I and vMIP-II had an apparent molecular mass of 7.8 kDa and were localized to the cytoplasm in a body cavity-based lymphoma cell line BC-3, stimulated with phorbol ester. We next treated a human monocytic leukemia cell line, THP-1, with purified recombinant vMIP-I and vMIP-II, or vMIP-I and vMIP-II fused with alkaline phosphatase to study Ca(2+) signalling and in vitro chemotaxis in response to these proteins. Calcium mobilization was induced by both vMIP-I and vMIP-II. Furthermore, vMIP-I and vMIP-II induced Ca(2+) mobilization in K562 cells expressing the CC chemokine receptor 5 (CCR5), suggesting that both may be agonistic for CCR5. Additionally, vMIP-I induced Ca(2+) mobilization through the intermediary of CCR8. These viral MIPs were also capable of chemotactically activating the THP-1 cells. These results imply that vMIP-I and vMIP-II may play important roles in the propagation of KS and primary effusion lymphoma by inducing the chemotaxis of CCR5-expressing monocytes.

Calcium↗
PubMed2003

Cyclooxygenase-2 expression in thyroid neoplasms.

AIMS: Previous studies have demonstrated that cyclooxygenase-2 (COX-2) plays a role in carcinogenesis and carcinoma development. In this study, we investigated its expression in thyroid neoplasms in order to elucidate its role. METHODS AND RESULTS: COX-2 expression was studied immunohistochemically in 20 anaplastic (undifferentiated) carcinomas, 49 papillary carcinomas, 22 follicular carcinomas and 15 follicular adenomas. Positive staining was only occasionally seen in normal follicles or stromal cells. COX-2 over-expression was found in only 20.0% of follicular adenomas and 40.9% of follicular carcinomas. In papillary carcinomas, the incidence (81.3%) was significantly higher (P < 0.0001) than in follicular carcinomas, although COX-2 expression was reduced in cases with old age (P = 0.0190), large size (P = 0.0028), advanced stage (P = 0.0225), satellite tumours (P = 0.0363), and the presence of solid, scirrhous or trabecular growth patterns (P = 0.0018). Undifferentiated carcinomas less frequently over-expressed COX-2 (P = 0.0004), with an incidence of 40.0%. CONCLUSIONS: These results indicate that the up-regulation of COX-2 may contribute predominantly in the early phase of papillary carcinoma progression, whereas it plays a more adjuvant role in follicular carcinoma progression.

Carcinoma↗
PubMed2003

Syndecan-1 expression in thyroid carcinoma: stromal expression followed by epithelial expression is significantly correlated with dedifferentiation.

AIM: To investigate the expression of syndecan-1 in thyroid neoplasia. Syndecan-1 is a proteoglycan regulating cell adhesion. Previous studies have demonstrated that decreased expression of syndecan-1 is linked to malignant progression. METHODS AND RESULTS: Syndecan-1 expression in thyroid neoplasia was studied immunohistochemically. Syndecan-1 was expressed in stromal cells as well as neoplastic epithelial cells. Stromal syndecan-1 expression was observed more frequently in papillary carcinomas larger than 10 mm in size than in microcarcinomas and in widely invasive than in minimally invasive follicular carcinomas. Furthermore, poorly differentiated carcinomas showed this phenomenon more than well-differentiated carcinomas, but the expression in undifferentiated carcinomas was similar to that of poorly differentiated carcinomas. Epithelial syndecan-1 expression was more frequently observed in anaplastic (undifferentiated) carcinomas than in papillary and follicular carcinomas. No significant difference in epithelial expression was found between well and poorly differentiated carcinomas, but undifferentiated carcinomas expressed epithelial syndecan-1 more frequently than did poorly differentiated carcinomas. CONCLUSIONS: These results are in contrast to those previously reported for carcinomas at other sites. It is suggested that the role of syndecan-1 in thyroid carcinomas might be unique. Stromal syndecan-1 expression followed by its epithelial expression is significantly related to progression, including dedifferentiation of thyroid carcinoma.

Adenocarcinoma↗
PubMed2003

A novel control process of cyanobacterial bloom using cyanobacteriolytic bacteria immobilized in floating biodegradable plastic carriers.

A process using a floating carrier for immobilization of cyanobacteriolytic bacteria, B.cereus N-14, was proposed to realize an effective in situ control of natural floating cyanobacterial blooms. The critical concentrations of the cyanobacteriolytic substance and B.cereus N-14 cells required to exhibit cyanobacteriolytic activity were investigated. The results indicated the necessity of cell growth to produce sufficiently high amounts of the cyanobacteriolytic substance to exhibit its activity and also for conditions enabling good contact between high concentrations of the cyanobacteriolytic substance and cyanobacteria. Floating biodegradable plastics made of starch were applied as a carrier material to maintain close contact between the immobilized cyanobacteriolytic bacteria and floating cyanobacteria. The floating starch-carriers could eliminate 99% of floating cyanobacteria in 4 d. Since B.cereus N-14 could produce the cyanobacteriolytic substance under the presence of starch and some amino acids, the cyanobacteriolytic activity could be attributed to carbon source fed from starch carrier and amino acids eluted from lysed cyanobacteria. Therefore, the effect of using a floating starch-carrier was confirmed from both view points as a carrier for immobilization and a nutrient source to stimulate cyanobacteriolytic activity. The new concept to apply a floating carrier immobilizing useful microorganisms for intensive treatment of a nuisance floating target was demonstrated.

Biocompatible Materials↗
PubMed2002

Heat shock protein genes and their functional significance in fish.

Despite decades of intensive investigation, important questions remain regarding the functional, ecological, and evolutionary roles of heat shock proteins. In this paper, we discuss the utility of fish as a model system to address these questions, and review the relevant studies of heat shock protein genes and the regulation of their expression in fish. Although molecular studies of the heat shock proteins in fish are still in their early descriptive phase, data are rapidly being collected. More is known about the biotic and abiotic factors regulating heat shock proteins. We briefly review these studies and focus on the role of heat shock proteins in development, their regulation by the endocrine system, and their importance in fish in nature. Functional genomics approaches will provide the tools necessary to gain a comprehensive understanding of the significance of heat shock proteins in the cellular stress response, in the physiological processes at higher levels of organization, and in the whole animal in its natural environment.

Adaptation, Physiological↗
PubMed2002

Expression of cdc25A and cdc25B proteins in thyroid neoplasms.

Cdc25B and cdc25A phosphates are prominent stimulators of cell cycle progression and recent studies have also suggested their oncogenic roles. To elucidate the role of these proteins in thyroid neoplasms, we immunohistochemically investigated their expression, and neither protein was expressed in normal follicular cells. Cdc25B was frequently overexpressed in follicular adenoma and minimally invasive follicular carcinoma, but the incidence was significantly lower in widely invasive follicular carcinoma. Furthermore, the cdc25B expression level significantly decreased with the dedifferentiation of thyroid carcinoma. Cdc25A overexpression was observed in high incidences in all types of thyroid neoplasms. These results suggest that cdc25B and cdc25A play oncogenic roles in thyroid follicules and that cdc25B works predominantly in the early phase of the progression of thyroid carcinoma, whereas cdc25A plays a fundamental role in the development of thyroid neoplasms.

Adenoma↗
PubMed2002

Caveolin-1 overexpression is an early event in the progression of papillary carcinoma of the thyroid.

Caveolin-1 is a major structural component of caveolae, which are plasma membrane microdomains implicated in the regulation of intracellular signalling pathways. Previous in vitro and in vivo studies on the function of caveolin-1 in carcinoma showed controversial results, indicating that the physiological role of caveolin-1 varies according to the origin of carcinoma. In this study, we investigated caveolin-1 expression in thyroid neoplasms by means of immunohistochemistry using a rabbit polyclonal antibody against caveolin-1. Normal follicular cells did not express caveolin-1. In papillary carcinoma, caveolin-1 expression was observed in high incidence, and especially in microcancer (less than 1.0 cm in diameter), caveolin-1 was positive in all cases except one. In undifferentiated (anaplastic) carcinoma, its incidence was significantly reduced. On the other hand, all cases of follicular carcinoma and adenoma were classified as negative for caveolin-1. These results suggest that caveolin-1 may play a role predominantly in the early phase of papillary carcinoma, whereas it has little influence on follicular tumours.

Adenoma↗
PubMed2002

Dense bone island: clinical features and possible complications.

A case of dense bone island in a girl aged 10 years, 1 month old is presented. The lesion was asymptomatic and was an incidental finding on a radiograph taken for another purpose. Nine months after the patient's first visit, an obvious inclination of adjacent teeth was identified. The size and density of the lesion had increased by 10 and 7%, respectively. As the patient was still in adolescence, the lesion may increase in size and density, potentially resulting in further problems such as increased inclination of the adjacent teeth. In addition, the presence of the lesion may complicate any future orthodontic treatment. The lesion should be kept under observation until its growth ceases.

Bone Density↗
PubMed2002

Screening and characterization of facultative psychrophilic denitrifiers for treatment of nitrate contaminated groundwater using starch-based biodegradable carriers.

Potential starch degrading denitrifying microorganisms that can grow at 4 degrees C were isolated from lake sediments to remove nitrate from groundwater. Initial screening using soluble starch as the sole carbon source confirmed that two out of twenty-five isolates (strain no. 2 and 47) significantly reduced nitrate in the medium and liberated nitrogen gas during culture. In a second screening, several commercially available starch based materials and different kinds of starch were tested. Strain 47 was found to have the best denitrification performance compared with strain 2. Using starch based carrier C (a commercial packing material) as carbon source, strain 47 could completely reduce the nitrate nitrogen in the medium after one week of batch culture even at 10 degrees C. Strain 47 could remove nitrate even without trace element supplementation, and it could perform optimally at 1X (10ml l(-1) of trace element solution) level of trace element supplement. The best temperature for denitrification for strain 47 was 15 degrees C and 20 degrees C, but it could also remove nitrate nitrogen at 10 degrees C and 30 degrees C, although at a slower rate. Reactor studies in a simulated treatment well (a cylindrical reciprocating basket reactor) in a repeated fed batch mode showed a good stable denitrification performance as long as substrate limitation is avoided by adequate supply of starch based carrier. Although the similarity score obtained was not enough for phylogenic identification, the results of 16SrRNA sequences analysis for the strain 47 showed a dose relation to Janthinobacterium lividum or Pseudomonas (Janth) mephitica (95.77%).

Bacteria↗
PubMed2002

Attenuation of glucan-binding protein C reduces the cariogenicity of Streptococcus mutans: analysis of strains isolated from human blood.

A blood isolate of Streptococcus mutans strain TW871 shows relatively low homology with MT8148, a reference oral isolate strain, and lacks the serotype-specific polysaccharide antigen, suggesting that other cell-surface structures correlate with cariogenicity. We compared cariogenicity of TW871 with MT8148 (serotype c) and blood isolate TW964 (serotype f) in rats. Strain TW871 showed significantly lower cariogenicity than MT8148 or TW964 and expressed significantly lower sucrose-independent cellular adhesion to saliva-coated hydroxyapatite and dextran-binding activity than strain MT8148. Strains TW871 and TW964 showed a defect in the gbpA gene by Southern hybridization analysis, while sequencing analysis revealed gbpC variation in TW871. These results suggest that variation in GbpC may alter cellular adherence properties and can be correlated with the cariogenicity of S. mutans in this strain.

Amino Acid Sequence↗
PubMed2002

CD44: functional relevance to inflammation and malignancy.

CD44 is a principal cell surface receptor for hyaluronan, a major component of extracellular matrices. Cells are surrounded by and encounter matrix in vivo, which in turn serves a variety of cell functions through the direct adhesion via their receptors. CD44 communicates cell-matrix interactions into the cell via "outside-in signaling" and has an important role in biological activities. The interaction of CD44 with fragmented hyaluronan on rheumatoid synovial cells induces expression of VCAM-1 and Fas on the cells, which leads to Fas-mediated apoptosis of synovial cells by the interaction of T cells bearing FasL. On the other hand, engagement of CD44 on tumor cells derived from lung cancer reduces Fas expression and Fas-mediated apoptosis, resulting in less susceptibility of the cells to CTL-mediated cytotoxicity through Fas-FasL pathway. Thus, although the CD44-mediated signaling differs among cells and circumstances, we here propose the functional role of CD44 in inflammatory processes and tumor susceptibility and the rational design of future therapeutic strategies including the exploitation of CD44-mediated pathway in vivo.

Animals↗
PubMed2002

[Relation between intraoperative salvaged blood transfusion and postoperative infection after cardiac surgery].

In cardiac surgery, several studies have shown bacterial contamination rates of intraoperative salvaged blood ranging from 12.7 to 96.8%. We evaluated the relation between intraoperative salvaged blood transfusion produced by the Cell Saver 5 device (Haemonetics Corp., Braintree, MA, USA) and postoperative infection determined by bacteriological study and the postoperative clinical course after cardiac surgery. Seven cases of cardiac surgery were investigated by bacteriological study. Although bacteria were cultured from all salvaged blood, no bacteria were cultured from the patients' blood 24 hours after salvaged blood infusion. Another 26 patients who underwent cardiac surgery, were divided into groups: group CS (n = 15) with salvaged blood transfusion after operation and group N (n = 11) without salvaged blood transfusion, and were evaluated in relation to the postoperative clinical course. There were no statistically significant differences between group CS and group N in the data of WBC, CRP and maximum body temperature. One case of deep sternal wound infection and 2 cases of local wound infection were observed in group CS, but none in group N (p = 0.18). These complications were treated by primary closure without muscle flaps. We conclude that salvaged blood autotransfusion was not related to postoperative infections in cardiac surgery.

Antibiotic Prophylaxis↗
PubMed2002

A novel strategy for cyanobacterial bloom control by ultrasonic irradiation.

The application of ultrasonic irradiation to control cyanobacterial blooms was evaluated in actual eutrophic lake water. Ten prototype units of the Ultrasonic Irradiation System (USIS) were installed in the 32 ha Lake Senba, and the water and sediment quality were monitored for 2 years. By incorporating the ultrasonication process with the on-going strategy, particularly flushing with induction water, cyanobacterial blooms can be controlled effectively. In addition, a significant improvement in the conditions of the lake in terms of chlorophyll-a, COD and T-P was attained. Moreover, the feasibility of ultrasonic irradiation and bacterial assisted control of cyanobacterial blooms was also evaluated in laboratory conditions. The destruction of gas vacuoles brought about by ultrasonic irradiation promoted close contact between cyanobacteria and their lysing Myxobacter leading to immediate and accelerated destruction of the cells.

Cyanobacteria↗
PubMed2002

Characterization of an algae-lytic substance secreted by Bacillus cereus, an indigenous bacterial isolate from Lake Kasumigaura.

In order to develop a practical biological strategy for water bloom-control in Lake Kasumigaura, indigenous algae-lytic bacteria targeting Microcystis spp. (the dominant cyanobacteria), was first carried out. Some basic lytic characteristics of the isolates concerning the biological and physico-chemical factors in actual water environments were then investigated. Fifteen algae-lytic bacteria were successfully isolated using the double layer method. The isolate showing the highest lytic activity was identified as Bacillus cereus based on the 16SrRNA sequence. Extracellular products of B. cereus were found to be responsible for algae-lytic activity. Algae-lytic assay tests using bacterial supernatants pre-treated under several conditions indicated that the majority of the effective algae-lytic substances were either hydrophilis or hydrophobics with a carbon number less than 18, and with molecular weight less than 2000 Da. The algae-lytic activity of the bacterial supernatant was found to be enhanced under alkaline conditions, but it was lost under acidic conditions. This pH specific characteristic is advantageous for application in water bloom environments where the pH is usually in the alkaline region.

Bacillus cereus↗
PubMed2001

In situ algal bloom control by the integration of ultrasonic radiation and jet circulation to flushing.

A novel strategy for in situ water bloom control was applied and evaluated in Lake Senba. The proposed strategy was to integrate ultrasonic radiation and water jet circulation to an existing flushing process for reducing the growth rate of cyanobacteria and to support the flushing process by providing efficient mixing. Ten units of the system, each consisting of an ultrasonication module and a water jet circulator module, were strategically situated on the lake, and the performance was monitored for 2 years. Water bloom occurrence reflected as chlorophyll a, SS, and transparency were controlled to lower levels when the integrated system was coupled with sufficient inflow water supply to achieve the target flushing rate. Also, an improvement in the water quality such as COD and phosphorus were observed. Based on linear regression analysis, relationships between water quality parameters and inflow water volume were discussed to evaluate the proposed strategy. Of the three major water quality parameters associated with water bloom, the integrated system contributed mainly to the reduction in SS and transparency compared to chlorophyll a reduction. Improved chlorophyll a reduction may be achieved by strategies that augment effective washout of cyanobacteria during flushing.

Carbohydrates↗