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K Kawamoto

Publications and source records attributed to K Kawamoto.

At least 19 recordsLinked to original sources
PubMed2006

Adenoviral-mediated overexpression of membrane-bound human FasL and human decoy Fas protect pig islets against human CD8+ CTL-mediated cytotoxicity.

Pig islets are considered to be most suitable source of islets for xenotransplantation into patients with type 1 diabetes mellitus. However, cellular rejection, especially CD8+ CTL-mediated cytotoxicity, remains a formidable barrier preventing long-term xenograft survival. Our previous study demonstrated that human CD8+ CTLs were highly detrimental to xenograft cells and that this strong cytotoxicity of human CTLs was mediated mainly by the Fas/FasL apoptotic pathway. Furthermore, we exploited novel methods for inhibiting human CD8+ CTL-mediated xenocytotoxicity with overexpression of membrane-bound human FasL and human decoy Fas antigen in xenografted cells. In the present study, we assessed the cytoprotective effects of these novel inhibitory molecules overexpressed by an adenoviral-mediated system in pig islets. Isolated pig islets were transfected with adenovirus vector encoding either human decoy Fas or membrane-bound human FasL genes. Thirty percent to 60% of transfected pig islets expressed these molecules producing 60% to 88% suppression of CTL killing compared with parental pig islets. These data indicated that pig islet grafts isolated from transgenic pigs with either membrane-bound human FasL or human decoy Fas antigen genes may control the innate cellular response to xenografts, and creating a window of opportunity to facilitate xenograft survival.

Adenoviridae↗
PubMed2006

A novel strategy for preventing human CD8+ cytotoxic T lymphocyte-mediated cytotoxicity against pig endothelial cells by overexpression of pig cellular FLICE-like inhibitory protein (c-FLIP) gene.

Human CD8+ cytotoxic T lymphocyte (CTL)-mediated cytotoxicity in xenograft recipients is an important obstacle for successful xenotransplantation of pig organs into humans. In our previous study, we demonstrated that xenocytotoxicity of human CD8+ CTL detrimental to pig endothelial cells (PEC) is mediated mainly by the Fas/FasL apoptotic pathway. Furthermore, we developed new methods to prevent this CTL killing by extracellular remodeling using overexpression of human decoy Fas antigen and membrane-bound human FasL on pig xenograft cells. The cellular FLICE-inhibitory protein (c-FLIP), a caspase-8 inhibitor that lacks the cysteine domain, is a negative regulator of death receptor-mediated apoptosis. c-FLIP proteins exist as long (c-FLIP(L)) and short (c-FLIPs) splice variants, both capable of protecting cells from death receptor-mediated apoptosis. In this report, we have demonstrated that both pig c-FLIPs and pig c-FLIP(L) significantly inhibit human CD8+ CTL-mediated xenocytotoxicity toward stably transfected PEC, although the expression level of pig Fas antigen on cell surface was not changed. These data suggested that intracellular remodeling with overexpression of pig c-FLIP in xenograft cells may decrease the innate cellular responses against xenografts, facilitating long-term xenograft survival.

Animals↗
PubMed2005

An outbreak of food-borne listeriosis due to cheese in Japan, during 2001.

Food-borne outbreaks caused by Listeria monocytogenes have been recognized in US and European countries. Only sporadic cases, of neonatal listeriosis, have been reported in Japan. Since L. monocytogenes has been often isolated from foods in Japan, food-borne outbreaks potentially could have occurred. In February 2001, L. monocytogenes serotype 1/2b was isolated from a washed-type cheese during routine Listeria monitoring of 123 domestic cheeses. Further samples from products and the environments at the plant that produced the contaminated cheese were examined for L. monocytogenes. L. monocytogenes serotype 1/2b was detected in 15 cheese samples, at most probable number that ranged from <30 to 4.6 x 10(9)/100 g, and in environmental samples. Studies with people who had consumed cheese from the plant revealed 86 persons who had been infected with L. monocytogenes. Thirty-eight of those people had developed clinical symptoms of gastroenteritis or the common cold type after the consumption of cheese. Isolates from those patients exhibited the same serotype, pathogenicity for mice and HeLa cells, DNA fingerprinting patterns and PCR amplification patterns. From the epidemiological and genetic evidence, it appeared that the outbreak was caused by cheese. This is the first documented incidence of food-borne listeriosis in Japan.

Cheese↗
PubMed2005

Resuscitation of the viable but non-culturable state of Salmonella enterica serovar Oranienburg by recombinant resuscitation-promoting factor derived from Salmonella Typhimurium strain LT2.

A gene encoding the resuscitation-promoting factor (Rpf) from Salmonella Typhimurium LT2 was cloned and characterized. The amino acid sequence encoded by S. Typhimurium LT2 rpf gene shares 24.2% homology with Micrococcus luteus Rpf, which is secreted by growing cells, and required to resuscitate from viable but non-culturable (VNC) state. The S. Typhimurium LT2 rpf gene is 696 bp long, and shared a conserved segment with Salmonella enterica serovar Oranienburg (99.4%). Recombinant Rpf (rRpf) proteins of S. Typhimurium LT2 after expression in E. coli BL21 harboring the pET15-b plasmid was approximately 25 kDa. Since S. Oranienburg cells are relatively quick to enter the VNC state just after incubating in the presence of 7% NaCl at 37 degrees C for 3 days, we evaluated the biological effect of rRpf by using S. Oranienburg VNC cells. The rRpf not only promoted proliferation but also induced resuscitation of VNC cells to the culturable state in a dose-dependent manner. Therefore, rRpf may be useful for detection of bacterial contaminants present in the VNC form in food samples and the environment.

Amino Acid Sequence↗
PubMed2005

Synergistic effects on the inhibition of human CD8+ cytotoxic T lymphocytes-mediated killing against xenograft cells by coexpression of membrane-bound Human FasL and decoy Fas antigen.

The principal barrier to the use of pigs as donors to humans is hyperacute rejection mediated by the interaction of alpha-gal abundantly expressed on pig cells and the natural anti-Gal antibody, abundantly produced in humans. This antibody-mediated hyperacute rejection may be overcome by an alpha1, 3 galactosyltransferase gene-knockout pig. However, xenograft cells could be rejected by T cells, especially CD8+ cytotoxic T lymphocytes (CTL)-mediated response, because these elements show great cytotoxicity against xenografted cells. We previously demonstrated that the Fas/FasL pathway is a major contributor to CD8+ CTL function. Furthermore, we sought to prevent this cytotoxicity by overexpression of membrane-bound FasL carrying the deletion at the metalloproteinase cleavage site or by decoy Fas antigen that does not contain the death domain in its cytoplasmic region. To investigate the effects of coexpression of these molecules, we cotransfected both genes into swine endothelial cells (SEC). The double-overexpression effectively prevented CD8+ CTL-mediated killing. Although cotransfectants and single transfectants of either membrane-bound FasL or decoy Fas gene showed similar inhibition of cytotoxicity, the expression levels of decoy Fas in SEC cotransfectants were much lower than those of decoy Fas single transfectants. These data suggest that beneficial effects for prevention of CTL-mediated xenocytotoxicity may be produced by the double expression of these molecules. The overexpression of both molecules on xenografted cells may decrease the innate cellular response to xenografts creating a window of opportunity to facilitate xenograft survival.

Acute Disease↗
PubMed2004

De novo formation characteristics of dioxins in the dry zone of an iron ore sintering bed.

The objectives of this work are to understand the details of the mechanism of dioxin formation in the part of a sintering bed termed the dry zone, and to obtain ideas on how to prevent their formation. Sinter mixtures of various composition types were heated in a packed bed reactor, and dioxins in the outlet gas and in the sinter mixture residue were measured. The dioxin formation potential of a simple sinter mixture composed of iron ore, coke and limestone was markedly lower than that of fly ash from a municipal solid waste incinerator (MSWI). In consideration of this result, a series of experiments were conducted using a sinter mixture impregnated with CuCl2. Experimental results showed that dioxin formation was temperature-dependent in the range of 300-550 degrees C, with the maximum observed at around 300 degrees C, which was quite similar to that of fly ash from the MSWI. The homologue distribution of PCDD/Fs in gas and solid reflected the possible difference in carbonaceous materials in coke and activated coke. Gaseous hydrogen chloride acted as a chlorinating reagent for dioxin formation.

Chlorine Compounds↗
PubMed2004

Protective immunity of SpaA-antigen producing Lactococcus lactis against Erysipelothrix rhusiopathiae infection.

AIMS: To develop an economical, safe and simple vaccination system against swine erysipelas using SpaA-antigen producing Lactococcus lactis. METHODS AND RESULTS: The spaA gene of Erysipelothrix rhusiopathiae was inserted into a shuttle plasmid pSECE1 to construct pSECE1.3. The SpaA produced in L. lactis maintained a stable antigenicity without degrading in growth. After mice were inoculated intranasally and orally with pSECE1.3-carrying L. lactis cells, IgG and IgA specific to SpaA were detected, and all the mice survived a challenge with 100 LD(50) of E. rhusiopathiae Tama-96 in the inner thigh. CONCLUSIONS: SpaA-producing L. lactis appears useful as an effective subunit vaccine against swine erysipelas. SIGNIFICANCE AND IMPACT OF THE STUDY: In this vaccination system, purification of the antigen and injection are unnecessary, leading to a reduced production cost, reduced labour and less stress to the animals. This vaccination system of the lactic acid bacteria should be a safe and suitable vehicle for a polyvalent vaccine.

Administration, Intranasal↗
PubMed2003

Rapid and effective detection of anthrax spores in soil by PCR.

AIMS: To detect Bacillus anthracis DNA from soil using rapid and simple procedures. METHODS AND RESULTS: Various amounts of B. anthracis Pasteur II spores were added artificially to 1 g of soil, which was then washed with ethanol and sterile water. Enrichment of the samples in trypticase soy broth was performed twice. A DNA template was prepared from the second enrichment culture using a FastPrep instrument. The template was then used for nested and real-time polymerase chain reaction (PCR) with B. anthracis-specific primers, to confirm the presence of B. anthracis chromosomal DNA and the pXO1/pXO2 plasmids. CONCLUSIONS: One cell of B. anthracis in 1 g of soil could be detected by nested and real-time PCR. The usefulness of the PCR method using field samples was also confirmed. SIGNIFICANCE AND IMPACT OF THE STUDY: The results indicate that this could be a useful method for detecting anthrax-spore contaminated soil with high sensitivity. Its application could have great impact on the progress of epidemiological surveillance.

Bacillus anthracis↗
PubMed2001

Nicotine inhibits UV-induced activation of the apoptotic pathway.

Although nicotine has been implicated as a potential factor in the pathogenesis of cancer in humans, its mechanism of action in the development of cancer remains largely unknown. Growing evidence indicates that the induction of apoptosis is an important mechanism in the prevention of cancer development. In the study presented here, we examined the effects of nicotine on the process of apoptosis. Preincubation of human cells with nicotine completely inhibited ultraviolet light (UV)-induced apoptosis. The inhibition of apoptosis by nicotine was correlated with the prevention of cytochrome c release and caspase activation, which are essential components of the UV-induced apoptotic pathway. Thus, our results suggest that the inhibition of apoptosis by nicotine contributes to the increased incidence of cancer in smokers.

Apoptosis↗
PubMed2001

Necessity of thromboxane A2 for initiation of platelet-mediated contact sensitivity: dual activation of platelets and vascular endothelial cells.

To investigate the crucial role of platelet-derived thromboxane A(2) (TXA(2)) in initiating Ag-specific contact sensitivity (CS), a platelet-dependent CS model using genetically mast cell-deficient W/W(v) mice, was provided. In vivo treatment with BAYu3405, a TXA(2) receptor antagonist, markedly suppressed CS responses in a dose-dependent manner. This inhibitory effect occurred when BAYu3405 was administered before an early initiating phase, suggesting that TXA(2) may be a potent initiator of platelet-mediated CS responses. When platelets were pretreated with BAYu3405 in vitro, platelet aggregation as well as serotonin release, which is able to induce the early phase response allowing local recruitment of CS effector T cells due to direct activation of vascular endothelial cells, was inhibited. The addition of U46619, a TXA(2) agonist, or a mixture of platelets and thrombin-enhanced expression of both ICAM-1 and VCAM-1 on isolated mouse aortic endothelial cells, which was completely abolished by pretreatment with BAYu3405. Furthermore, intradermal injection of U46619 into the ear of platelet-depleted mice led to CS responses with marked expression of ICAM-1 and VCAM-1 on the vascular endothelium. These findings suggest that TXA(2) generated from platelets activated with Ag may mediate initiation of CS responses through inducing serotonin release from platelets and the subsequent aggregation and up-regulated expression of ICAM-1 and VCAM-1 on vascular endothelial cells.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2001

The functional and structural outcome of inner ear gene transfer via the vestibular and cochlear fluids in mice.

Mice present an ideal model for inner ear gene therapy because their genome is being rapidly sequenced, their generation time is relatively short, and they serve as a valuable model for human hereditary inner ear disease. However, the small size of the mouse inner ear poses a particular challenge for surgical procedures. We have developed a new approach for viral inoculation into the mature mouse inner ear, using a replication-deficient adenovirus expressing the bacterial gene lacZ. We administered the virus through the posterior semicircular canal (canalostomy) and into the cochlea (cochleostomy). Both approaches caused lacZ to be expressed in cells lining the perilymphatic space. One canalostomy case showed gene expression in sensory cells of the crista ampullaris, whereas the cochleostomy group showed gene expression in the sensory cells in the organ of Corti and saccule. Functional tests after the surgery showed that the canalostomy preserved hearing, whereas the cochleostomy did not. Any vestibular function transiently lost after the canalostomy was recovered. Our findings indicate that inoculation of adenovirus vectors into the mouse inner ear through the semicircular canal has the potential to efficiently introduce transgenes to the vestibular system and the cochlea without compromising hearing.

Adenoviridae↗
PubMed2001

Evaluation and comparison of multimedia mass balance models of chemical fate: application of EUSES and ChemCAN to 68 chemicals in Japan.

The European Union System for Evaluation of Substances (EUSES) and the ChemCAN chemical fate model are applied to describe the fate of 68 chemicals on two spatial scales in Japan. Emission information on the chemicals has been obtained from Japan's Pollutant Release and Transfer Registry and available monitoring data gathered from government reports. Environmental concentrations calculated by the two models for the four primary environmental media of air, water, soil and sediment agree within a factor of 3 for over 70% of the data, and within a factor of 10 for over 87% of the data. Reasons for certain large discrepancies are discussed. Concentrations calculated by the models are generally consistent with the lower range of concentrations that are observed in the environment. Agreement between modeled and observed concentrations is considerably improved by including an estimate of the advective input of chemicals in air from outside Japan. The agreement between the EUSES and ChemCAN models suggests that results of individual chemical assessments are not likely to be significantly affected by the choice of chemical fate model. Primary sources of discrepancy between modeled and observed concentrations are believed to be uncertainties in emission rates, degradation half-lives, and the lack of data on advective inflow of contaminants in air.

Biodegradation, Environmental↗
PubMed2001

Aminoglycoside ototoxicity in adult CBA, C57BL and BALB mice and the Sprague-Dawley rat.

The availability of genetic information, transgenic and knock-out animals make the mouse a primary model in biomedical research. Aminoglycoside ototoxicity, however, has rarely been studied in mature mice because they are considered highly resistant to the drugs. This study presents models for kanamycin ototoxicity in adult CBA/J, C57BL/6 and BALB/c mouse strains and a comparison to Sprague-Dawley rats. Five-week-old mice were injected subcutaneously twice daily with 400-900 mg kanamycin base/kg body weight for 15 days. Kanamycin induced dose-dependent auditory threshold shifts of up to 70 dB at 24 kHz as measured by auditory brain stem-evoked responses. Vestibular function was also affected in all strains. The functional deficits were accompanied by hair cell loss in both cochlear and vestibular neurosensory epithelia. Concomitant administration of the antioxidant 2,3-dihydroxybenzoate significantly attenuated the kanamycin-induced threshold shifts. In adult male Sprague-Dawley rats, doses of 1 x 500 mg or 2 x 300 mg kanamycin base/kg body weight/day x 14 days induced threshold shifts of approximately 50 dB at 20 kHz. These were accompanied by loss of outer hair cells. The order of susceptibility, BALB>CBA>C57, was not due to differences in the pharmacokinetics of kanamycin. It also did not correlate with the presence of Ahl/Ahl2 genes which predispose C57 and BALB strains, respectively, to accelerated age-related hearing loss. Pigmentation, however, paralleled this rank order suggesting an influence of melanin on cochlear antioxidant status.

Aminoglycosides↗
PubMed2001

Induction of collagenase-2 (matrix metalloproteinase-8) gene expression by interleukin-1beta in human gingival fibroblasts.

Collagenase-2 (matrix metalloproteinase-8 or MMP-8) is synthesized mainly by polymorphonuclear neutrophils and plays a crucial role in inflammatory periodontal tissue destruction. We tested the effect of interleukin(IL)-1beta, a proinflammatory cytokine, on collagenase-2 gene expression in cultured human gingival fibroblasts and also compared this effect with IL-1beta-induced changes in collagenase-1 and -3 gene expression. By a combination of reverse transcription-polymerase chain reaction and Southern analysis, IL-1beta was found to dose-dependently induce gene expression for collagenase-1, -2, and -3 in gingival fibroblasts. Although collagenase-2 mRNA was the least abundant among the three collagenase mRNAs tested in the cultured fibroblast system, addition of 1 ng/ml IL-1beta significantly increased collagenase-2 gene transcription within 6 h, and maximal stimulation was maintained for 12 to 48 h. Significant mRNA induction was observed with as little as 0.1 ng/ml IL-1beta. IL-1beta was also found to increase the stability of collagenase-2 mRNAs after transcription arrest was induced by an RNA polymerase inhibitor. Stimulation of collagenase-2 mRNA expression by IL-1beta was prevented by pretreatment with cycloheximide, an inhibitor of protein synthesis. These results indicate that IL-1beta increased mRNA expression for collagenases including collagenase-2 in gingival fibroblasts. The findings also suggest that enhancement of collagenase-2 mRNA expression by IL-1beta involves both protein synthesis and suppression of mRNA degradation.

Analysis of Variance↗
PubMed2001

[Feasibility of inner ear gene transfer after middle ear administration of an adenovirus vector].

BACKGROUND: Several groups demonstrated in animal experiments that gene transfer is a feasible tool for inner ear intervention. Various approaches for inoculation of vectors have been successfully used for inner ear gene therapy. One possible way to reduce the risk of hearing loss following the opening of the cochlea for application of the vector into the perilymphatic space is to deliver vectors through the round window. This study was designed to determine whether middle ear application of an adenoviral vector is a feasible approach to inoculate vectors and lead to transduction of cells in the inner ear. METHODS: A unilateral middle ear application of an adenoviral vector was performed in 4 guinea pigs directly on the round window membrane (RWM) and in 4 additional animals by placing a cotton patch soaked with the vector solution on the RWM. The expression of a reporter gene (lacZ) was used to localize vector-transduced cells. RESULTS: Only one out of 8 animals showed cochlear expression of the reporter gene, whereas all 8 animals showed strong lacZ expression in the middle ear mucosa, in the RWM and in the mucosa surrounding the stapes. CONCLUSION: Our results indicate that the RWM presents a close barrier, almost completely preventing the adenovirus to diffuse into the perilymphatic space. Therefore middle ear application of an adenoviral vector cannot be used to induce inner ear gene transfer. However, middle ear application of a viral vector may be useful for developing treatment for diseases of the middle ear mucosa.

Adenoviruses, Human↗
PubMed2001

Establishment and characterization of a murine mast cell line derived from NC/Nga mice.

A cell line, termed NCJ, was established from the bone marrow-derived mast cells (BMMCs) of NC/Nga mice that are mouse models for atopic dermatitis. NCJ cells expressed FcepsilonRI and c-kit and showed a metachromasia of the granules with a toluidine blue-positive and safranin-negative staining pattern that is characteristic for immature-type mast cells. Interestingly, NCJ cells showed proliferation independent of IL-3, which was associated with constitutive phosphorylation of Raf-1 and Erk kinases. Although NCJ cells had several characteristics of mast cells, we failed to detect FcepsilonRI-mediated beta-hexosaminidase release and its histamine content. These findings indicated that NCJ cells represented a mast cell line with an immature phenotype and the ability to proliferate in the absence of mast cell growth factors. NCJ cells might thus be useful to study the molecular basis of mast cell proliferation.

Animals↗
PubMed2001

Relationship between sprint performance and muscle fascicle length in female sprinters.

The purpose of this study was to investigate the relationship between sprint performance and architectural characteristics of leg muscles in 26 female 100-m sprinters. Pennation angle and muscle thickness of the vastus lateralis (VL) and gastrocnemius medialis (GM) and lateralis (GL) muscles were measured by B-mode ultrasonography, and fascicle length was estimated. Sprinters had a significantly lower VL pennation angle, but GM and GL pennation angle was similar between sprinters and female control subjects (N = 22). There was no significant correlation between pennation angle and 100-m personal best performance. Sprinters had significantly greater absolute fascicle length in VL and GL than controls, which significantly correlated to 100-m best-record (r = -0.51 and r = -0.44, respectively). Relative fascicle length (VL and GL) were also significantly greater in sprinters than controls. However, there were no significant correlation between relative fascicle length and 100-m best-record (r = -0.36 and r = -0.29, respectively). No relationship was found between the sprint performance and fat-free mass (r = -0.26) or body mass index (r = -0.03). However, there was a significant correlation between percent (%) body fat and 100-m best-record (r = 0.62, p < 0.01). Adjusting the confounding effect of % fat, significant correlations were seen between relative fascicle length and 100-m best-record (VL; r = -0.39 and GL; r = -0.40). Absolute and relative fascicle length were similar in elite female sprinters compared with previous reported values for elite male sprinters (Kumagai et al., 2000). It was concluded that longer fascicle length is associated with greater sprinting performance in sprinters, but there is no gender differences in fascicle length for elite sprinters.

Adult↗