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N Yamaguchi

Publications and source records attributed to N Yamaguchi.

At least 19 recordsLinked to original sources
PubMed2006

Long-term mobility of fallout 90Sr in ploughed soil, and 90Sr uptake by wheat grain.

In this study, we evaluated the mobility of 90Sr in ploughed upland soil, which affects the residual amount in the soil and plant uptake on the basis of long-term monitoring data. Paired samples of soil and wheat grain were taken annually from 1961 to 1995 from 8 agricultural fields in Japan, and the concentrations of exchangeable 90Sr in soil and total 90Sr in wheat grain were determined. The concentration of exchangeable 90Sr in ploughed soil decreased exponentially with time. The environmental factor responsible for the decrease of exchangeable 90Sr in the ploughed layer, lambda(e), was determined from the monitoring data of exchangeable 90Sr in the ploughed soil and the amount of fallout-derived deposition. The lambda(e) was larger from 1970 to 1980 than it was from 1980 to 1995, suggesting that an easily removable fraction of 90Sr in soil was preferentially lost from ploughed soil. Among various soil properties that we investigated, the main factor controlling the long-term mobility of 90Sr from ploughed upland soil and 90Sr uptake by wheat grain was the cation-exchange capacity (CEC) of soil. Our experimental results indicate that the entrapment of 90Sr on a cation-exchange site retards the downward migration and wheat uptake of 90Sr from ploughed soil. The empirical parameters that we obtained based on the long-term observation of a wheat-cultivated upland field in Japan could be used as reference data in order to roughly estimate the mobility of 90Sr in ploughed soil and soil-borne 90Sr transfer to wheat grain in the humid Japanese climate.

Agriculture↗
PubMed2006

Mobile phone use and acoustic neuroma risk in Japan.

OBJECTIVES: The rapid increase of mobile phone use has increased public concern about its possible health effects in Japan, where the mobile phone system is unique in the characteristics of its signal transmission. To examine the relation between mobile phone use and acoustic neuroma, a case-control study was initiated. METHODS: The study followed the common, core protocol of the international collaborative study, INTERPHONE. A prospective case recruitment was done in Japan for 2000-04. One hundred and one acoustic neuroma cases, who were 30-69 years of age and resided in the Tokyo area, and 339 age, sex, and residency matched controls were interviewed using a common computer assisted personal interview system. Education and marital status adjusted odds ratio was calculated with a conditional logistic regression analysis. RESULTS: Fifty one cases (52.6%) and 192 controls (58.2%) were regular mobile phone users on the reference date, which was set as one year before the diagnosis, and no significant increase of acoustic neuroma risk was observed, with the odds ratio (OR) being 0.73 (95% CI 0.43 to 1.23). No exposure related increase in the risk of acoustic neuroma was observed when the cumulative length of use (<4 years, 4-8 years, >8 years) or cumulative call time (<300 hours, 300-900 hours, >900 hours) was used as an exposure index. The OR was 1.09 (95% CI 0.58 to 2.06) when the reference date was set as five years before the diagnosis. Further, laterality of mobile phone use was not associated with tumours. CONCLUSIONS: These results suggest that there is no significant increase in the risk of acoustic neuroma in association with mobile phone use in Japan.

Adult↗
PubMed2006

Gastrointestinal Candida colonisation promotes sensitisation against food antigens by affecting the mucosal barrier in mice.

BACKGROUNDS AND AIMS: Controversy still exists as to whether gastrointestinal colonisation by Candida albicans contributes to aggravation of atopic dermatitis. We hypothesised that Candida colonisation promotes food allergy, which is known to contribute to a pathogenic response in atopic dermatitis. We tested this using a recently established murine Candida colonisation model. METHODS: Candida colonisation in the gastrointestinal tract was established by intragastric inoculation with C albicans in mice fed a synthetic diet. To investigate sensitisation against food antigen, mice were intragastrically administered with ovalbumin every other day for nine weeks, and antiovalbumin antibody titres were measured weekly. To examine gastrointestinal permeation of food antigen, plasma concentrations of ovalbumin were measured following intragastric administration of ovalbumin. RESULTS: Ovalbumin specific IgG and IgE titres were higher in BALB/c mice with Candida colonisation than in normal mice. Gastrointestinal permeation of ovalbumin was enhanced by colonisation in BALB/c mice. Histological examination showed that colonisation promoted infiltration and degranulation of mast cells. Candida colonisation did not enhance ovalbumin permeation in mast cell deficient W/Wv mice but did in congenic littermate control +/+ mice. Reconstitution of mast cells in W/Wv mice by transplantation of bone marrow derived mast cells restored the ability to increase ovalbumin permeation in response to Candida colonisation. CONCLUSIONS: These results suggest that gastrointestinal Candida colonisation promotes sensitisation against food antigens, at least partly due to mast cell mediated hyperpermeability in the gastrointestinal mucosa of mice.

Animals↗
PubMed2006

Induction of Porphyromonas gingivalis GroEL signaling via binding to Toll-like receptors 2 and 4.

BACKGROUND/AIMS: Heat shock protein 60 (HSP60) has been recognized as an important molecule in infectious and autoimmune diseases. Although Porphyromonas gingivalis GroEL, a homologue of HSP60, is a potent stimulator of inflammatory cytokines, its receptor and signaling mechanisms are not yet understood in detail. In this study, we investigated whether the Toll-like receptor (TLR) family plays a functional role as a P. gingivalis GroEL receptor. METHODS: Human macrophage-like THP-1 cells were used and the nuclear factor-kappaB (NF-kappaB) activity of cells stimulated with a recombinant P. gingivalis GroEL was measured with a luciferase assay. Flow cytometry analysis was used to determine the binding to THP-1 cells of fluorescein isothiocyanate (FITC)-labeled GroEL. In addition, anti-human TLR (anti-hTLR)2 and anti-hTLR4 monoclonal antibodies were used to assess the functional role of TLR2 and TLR4 as the receptors for GroEL. RESULTS: We observed by luciferase assay that the purified recombinant GroEL was able to stimulate NF-kappaB transcriptional activity in THP-1 cells. Flow cytometry analysis showed that the FITC-labeled GroEL bound to THP-1 cells in a dose-dependent fashion. Our binding competition analysis with FITC-labeled and unlabeled GroEL showed that it bound to the cells as a specific mode of action. On the other hand, GroEL-stimulated NF-kappaB transcriptional activity was significantly inhibited by anti-hTLR2 and anti-hTLR4 antibodies and was inhibited more strongly by a combination of both antibodies. CONCLUSION: Our present study demonstrates that P. gingivalis GroEL induces its intracellular signaling cascade in THP-1 cells via TLR2 or TLR4 and via a combination of both receptors.

Antibodies, Monoclonal↗
PubMed2006

Simple detection of small amounts of Pseudomonas cells in milk by using a microfluidic device.

AIMS: Flow cytometry offers rapid and reliable analyses of bacteria in milk. However, a flow cytometer is relatively expensive and operation is rather complicated for an unskilled operator. We applied flow cytometry using a microfluidic device (on-chip flow cytometry) in detection of small amounts of milk-spoiling bacteria. METHODS AND RESULTS: Pseudomonas cells in milk were in situ hybridized with Cy5-labelled probe specific for Pseudomonas spp. under optimized condition. Numbers of Pseudomonas cells in the stationary phase and in the starved state determined by on-chip flow cytometry were compared with those determined by conventional plate counting, and on-chip flow cytometry detected targeted cells in milk that were undetectable as colony forming units(CFU) on Standards Methods Agar. CONCLUSIONS: The contamination in milk with fewer than 10 CFU ml(-1) of targeted cells in starved state was detectable with simple procedure (0.5 h milk-clearing, 1 h fixation, 2 h hybridization and 0.5 h on-chip flow cytometry following 12 h enrichment of cells). SIGNIFICANCE AND IMPACT OF THE STUDY: On-chip flow cytometry following fluorescence in situ hybridization could be applicable to simple detection of milk-spoiling bacteria.

Animals↗
PubMed2005

Redox reaction of iodine in paddy soil investigated by field observation and the I K-Edge XANES fingerprinting method.

In order to elucidate the cause for the leaching of iodine in a flooded paddy field, we investigated the transformation of an iodine species affected by the water management of the paddy field. The increased concentration of iodide (I(-)) in soil solution of a flooded paddy field suggested that I(-) was leached from the soil under anaerobic conditions. The post-edge feature of X-ray absorption near-edge structure (XANES) for iodate (IO(3)(-)) spiked to soil totally disappeared after anaerobic incubation of the soils, and I(-) was dissolved in the solution. On the other hand, I(-) in contact with the soil was not likely to be oxidized to IO(3)(-) under aerobic incubation. Iodine was leached out in soil solution as I(-) under anaerobic conditions, whereas part of the iodine species was retained by soil as I(2) or organoiodine both under anaerobic and aerobic conditions.

Iodine↗
PubMed2005

Multicolour digital image analysis system for identification of bacteria and concurrent assessment of their respiratory activity.

AIMS: To develop a rapid and simple multicolour digital image analysis system for simultaneous identification of bacteria and assessment of their metabolic activity. METHODS AND RESULTS: We developed an image analyser capable of distinguishing triple-stained bacterial cells. Bacteria were stained with a nucleic acid stain, a fluorescent antibody and a fluorescent metabolic indicator for enumeration, species identification and assessment of metabolic activity. This multicolour image analyser was used to simultaneously identify Escherichia coli O157:H7 in milk samples and assess their respiratory activity. The images of the triple-stained bacteria were captured using a combination of blue light and u.v. excitation and an epifluorescence microscope and were processed by our image analyser. We found a good correlation between the counts of actively respiring (r = 0.93) and total (r = 0.94) E. coli O157:H7 measured by digital image analysis and visual observation. CONCLUSION: The multicolour digital image analysis system described here was able to quantify active pathogenic micro-organisms within 2 h. SIGNIFICANCE AND IMPACT OF THE STUDY: This multicolour image analysis allows the rapid and simultaneous quantification of bacteria, identification of species and assessment of metabolic activity.

Animals↗
PubMed2005

Rapid monitoring of microbial contamination on herbal medicines by fluorescent staining method.

AIMS: To apply fluorescent staining method for fast assessment of microbial quality of herbal medicines. METHODS AND RESULTS: The number of total bacteria and esterase-active bacteria on powdered traditional Chinese medicines were enumerated by fluorescent staining method using 6-carboxyfluorescein diacetate (6CFDA) and 4',6-diamidino-2-phenylindole (DAPI), and they were compared with colony-forming units (CFU). The CFU was approximately 10(3) per gram in ginseng radix, and no bacterial colonies were detected from others. However, the total bacterial number (TDC) was more than 10(7) per gram, and number of bacteria possessing esterase activity ranged from 1 to 3% of TDC. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Many bacteria in each Chinese medicine had enzyme activity and most of them could not be detected by conventional plate counting technique. Enumeration of bacterial cells on traditional Chinese medicines by fluorescent staining method requires less than 1 h. The double staining method with 6CFDA and DAPI could be applicable to rapid microbial monitoring of crude drugs.

Animals↗
PubMed2004

The Eating Disorder Inventory-2 in Japanese clinical and non-clinical samples: psychometric properties and cross-cultural implications.

OBJECTIVE: To determine the usefulness of and cross-cultural differences in the Japanese version of the eating disorder inventory-2 (EDI-2). METHOD: A Japanese version of the EDI-2 was administered to a consecutive series (1995-2001) of 91 Japanese eating disordered inpatients and 119 matched non-clinical controls. Scores were compared with each other and with those of Canadian data previously reported. Internal consistencies were also examined. RESULTS: All subscales (except Ascetism) reached sufficient internal consistencies. The patients' mean scores were significantly higher than controls on most subscales. Restricting anorexics (AN-R) scored higher than controls on body dissatisfaction (BD) and Social Insecurity (SI) subscales. Purging bulimics (BN-P) scored higher than controls on most subscales, except for maturity fears (MF) and SI subscales. Scores of binge-eating/purging type anorexics (AN-B/P) were higher than controls on all subscales. AN-B/P and BN-P scored higher than AN-R on bulimia (B) subscale. Comparison with Canadian subjects showed that Japanese control subjects scored significantly higher on the MF, ineffectiveness (I), impulse regulation (IR), SI subscales, and lower on the perfectionism (P) subscale. DISCUSSION: The EDI-2 is useful and reliable in understanding Japanese clinical and non-clinical samples. High MF and low P subscales in our samples confirm previous findings in Chinese samples suggesting meaningful cultural differences in the emphasis placed on family bonds and individual accomplishments. In addition, high I, IR, and SI scores in Japanese non-clinical samples may reflect recent problems in Japanese culture.

Adult↗
PubMed2004

IL-12 Production Induced by Agaricus blazei Fraction H (ABH) Involves Toll-like Receptor (TLR).

Agaricus blazei Murill is an edible fungus used in traditional medicine, which has various well-documented medicinal properties. In the present study, we investigated the effects of hemicellulase-derived mycelia extract (Agaricus blazei fraction H: ABH) on the immune system. First, we examined the cytokine-inducing activity of ABH on human peripheral mononuclear cells (PBMC). The results indicated that ABH induced expression of IL-12, a cytokine known to be a critical regulator of cellular immune responses. Flow cytometric analysis demonstrated the induction of IL-12 production by the CD14-positive cell population, consisting of monocytes/macrophages (Mo/Mphi). Furthermore, the elimination of Mo/Mphi attenuated IL-12 production in PBMC. ABH-induced IL-12 production was inhibited by anti-CD14 and anti-TLR4 antibodies but not by anti-TLR2 antibody. The activity of ABH was not inhibited by polymyxin B, while the activity of lipopolysaccharide used as a reference was inhibited. Oral administration of ABH enhanced natural killer (NK) activity in the spleen. These findings suggest that ABH activated Mo/Mphi in a manner dependent on CD14/TLR4 and NK activity.

Journal Article↗
PubMed2004

Bacterial population dynamics and community structure in a pharmaceutical manufacturing water supply system determined by real-time PCR and PCR-denaturing gradient gel electrophoresis.

AIMS: To control bacteria in the pharmaceutical water supply system. METHODS AND RESULTS: Bacteria were enumerated by conventional culture method and fluorescent vital staining. Activated carbon treatment and storage in a tank provided favourable environments for bacterial growth. The bacterial population of the water in both the post-activated carbon treatment and the tank was analysed by denaturing gradient gel electrophoresis (DGGE) with PCR-amplified 16S rDNA fragments including V6, -7, and -8 regions. The bacterial community structure in activated carbon treated water was stable throughout the year. Several kinds of bacteria such as genus Aquaspirillum and Methylobacterium were found in the water after activated carbon treatment. The bacterial community structure was changed and other bacteria such as mycobacteria were detected after storage. Mycobacteria were quantified in water samples using real-time PCR targeting the 16S rDNA gene. Mycobacteria were also detected in tap water and their number was increased 10(3)-10(4)-fold higher after storage. CONCLUSION: These data suggest the importance of culture-independent methods for quality control of water used in pharmaceutical manufacturing. SIGNIFICANCE AND IMPACT OF THE STUDY: Critical steps and specified bacteria that should be controlled in the water supply system were recognized by culture-independent methods. These data will enable effective control of water used in the pharmaceutical industry.

Bacteria↗
PubMed2003

Concentrations and hazard assessment of PCBs, organochlorine pesticides and mercury in fish species from the Upper Thames: river pollution and its potential effects on top predators.

Aquatic environmental contamination levels of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and heavy metals in the Upper Thames catchment area, UK were assessed on the basis of fish muscle analysis in wet weight, and their effects on top predators were assessed. The contamination levels of lead, cadmium, dichloro-diphenyl-trichloroethane (DDT) and its metabolites were found to be low (undetectable) in the area. Average mercury contamination level varied between 55 and 342 microg/kg, dieldrin between less than 0.09 and 36.8, lindane between < 0.08 and 4.94, and PCBs between < 0.77 and 3.32. Eels (Anguilla anguilla) had always much higher concentration of OCPs compared to the other fishes from the same monitoring sites. The environmental contamination level of PCBs may be partly associated with industrial and human activities, however, it was difficult to find such associations for mercury level. The hazard indices (HI) of both dieldrin and PCBs were below 1 for mink (Mustela vison). However, the HI of mercury of the all fish species from all monitoring sites are above 1 for mink. These contamination levels may be less harmful to polecats (Mustela putorius), but more so to otters (Lutra lutra) as their diets are dominated by aquatic prey.

Animals↗
PubMed2003

Development of multicolour digital image analysis system to enumerate actively respiring bacteria in natural river water.

AIMS: To develop a rapid and simple method for the assessment of metabolic activity of bacteria in natural environment. METHODS AND RESULTS: A rapid and simple multicolour digital image analysis system for enumerating viable bacteria based on active fluorescent staining has been developed. This system can accurately differentiate actively respiring bacteria and non-respiring bacteria by distinctive colour information in the digital image captured by an epifluorescence microscope equipped with low magnification objective lens. An algorithm to distinguish bacteria from considerable detritus, which produced bright fluorescence in different colours, by colour segmentation has also been developed. This system was applied to river water samples, and the total and respiratory active bacterial counts by digital image analysis were highly related to those by epifluorescence microscopy (r2 = 0.96 and 0.93, respectively). CONCLUSION: This system allowed the rapid and simple differentiation of bacteria from detritus and concurrent assessment of their metabolic activity, with results being available within 1 h. SIGNIFICANCE AND IMPACT OF THE STUDY: The low magnification image analysis allows more rapid and simple quantification of bacteria and could considerably decrease image data amount and acquisition time. This system could be easily applied to the rapid analysis of microbes in various environments.

Algorithms↗
PubMed2003

Inhibition of arthritis by systemic administration of endostatin in passive murine collagen induced arthritis.

OBJECTIVE: To investigate the arthritis inhibiting effect of endostatin, known to have potent antiangiogenic activity, systemically given to animal models of rheumatoid arthritis (RA). METHODS: Four kinds of monoclonal anti-type II collagen antibody followed by lipopolysaccharide (LPS) three days later were given to 6 week old, female Balb/c mice to induce arthritis. Three groups of mice received 0.2 mg/kg/day, 2 mg/kg/day, and 10 mg/kg/day of endostatin, respectively, whereas a control group received phosphate buffered saline (PBS). Endostatin or PBS was given for 13 days, starting before the development of arthritis. Arthritis was evaluated by arthritis scores and hind paw thicknesses. Mice were killed for histological examination on the 22nd day after the administration of monoclonal anti-type II collagen antibody. RESULTS: Arthritis developed within three days after LPS administration in both the control and endostatin treatment groups. No difference in the development rate of arthritis was noted between the control and endostatin treatment groups. Arthritis scores remained significantly lower in the endostatin 10 mg/kg/day group than in the control group. Hind paw thicknesses also remained significantly smaller in the endostatin 10 mg/kg/day group than in the control group. Histopathological examination showed that synovial thickening and subchondral bone erosion improved more in the endostatin treatment groups than in the control group. CONCLUSION: The systemic administration of endostatin had an arthritis inhibiting effect in RA animal models. Endostatin inhibited, in particular, pannus formation and bone destruction.

Analysis of Variance↗
PubMed2002

Activation of the alternative complement pathway by Agaricus blazei Murill.

Components of Agaricus blazei Murill have been demonstrated to have a wide range of immunopotentiating activities. The present study was designed to evaluate the effect of A. blazei Murill upon activation of the complement system in human serum in vitro. Additional studies were performed to determine the cytotoxic effect of complement-opsonized particles of A. blazei Murill against human tumor cells in culture. A fine particle of A. blazei Murill (ABP), prepared by mechanical disruption, was used throughout the experiments. ABP activated the human complement system via the alternative pathway in human serum. Activation of the alternative pathway was both time- and dose-dependent. When the particles from fruiting bodies of A. blazei Murill (ABP-F) were reacted with human serum, the formation of complement-opsonized ABP, iC3b-ABP-F complexes, and binding of the complexes to human peripheral blood monocytes, were demonstrated in vitro by immunofluorescence. Further, the resident human peripheral nucleated cells incubated in the presence of iC3b-ABP-F complexes inhibited the proliferation of human tumor cell line TPC-1 in vitro.

Adult↗