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M Kijima

Publications and source records attributed to M Kijima.

At least 19 recordsLinked to original sources
PubMed2006

Differences between Lactococcus garvieae isolated from the genus Seriola in Japan and those isolated from other animals (trout, terrestrial animals from Europe) with regard to pathogenicity, phage susceptibility and genetic characterization.

AIMS: To clarify the epidemiological relationship between Lactococcus garvieae isolates from the Seriola in Japan and isolates from other animals. METHODS AND RESULTS: A total of 32 isolates obtained from aquatic (the genus Seriola and trout) and terrestrial animals (cow, pig, cat, dog and horse) was used to evaluate its pathogenicity to yellowtail and mouse, phenotype (KG+ and KG-), its susceptibility to three bacteriophages and the pattern of pulsed field gel electrophoresis (PFGE). Lactococcus garvieae isolated from Seriola showed strong pathogenicity to yellowtail, while isolates from trout showed weak pathogenicity and those obtained from terrestrial animals showed no distinct pathogenicity. Only, the isolates from the genus Seriola in Japan showed susceptibility to the bacteriophages. The results of PFGE pattern indicate that the isolates obtained from the Seriola predict homogeneity, while there is no similarity among the isolates obtained from different animals. CONCLUSION: This experiment indicates that L. garvieae isolated from Seriola in Japan appears to be very different from the isolates obtained from other animals, and the isolates prevalent among the genus Seriola in Japan might be homogeneous. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that a particular genetic group that has specially adapted and acquired virulence toward yellowtail were prevalent among the genus Seriola in Japan.

Animals↗
PubMed2006

Drug resistance and random amplified polymorphic DNA analysis of Photobacterium damselae ssp. piscicida isolates from cultured Seriola (yellowtail, amberjack and kingfish) in Japan.

AIMS: To investigate the antimicrobial susceptibility and genetic characteristics of Photobacterium damselae ssp. piscicida isolates obtained from cultured Seriola in Japan. METHODS AND RESULTS: Minimal inhibitory concentrations of 14 antimicrobials for 74 isolates from Seriola in Japan in 2002 were determined. Isolates showed high frequencies of resistance to sulfamonomethoxine (SMMX) (97.3%), oxytetracycline (OTC) (77.0%), flumequine (FMQ) (77.0%), chloramphenicol (CP) (75.7%), kanamycin (KM) (63.5%) and oxolinic acid (OA) (62.0%), but low to ampicillin (ABPC) (2.8%). All isolates were susceptible to bicozamycin (BCM), fosfomycin (FOM) and florfenicol (FF). Of these isolates, 45 (60.8%) showed same resistance pattern (SMMX-OTC-FMQ-OA-CP-KM). In random amplified polymorphic DNA (RAPD) analysis, no difference was observed among our 74 field isolates and ATCC51736 isolated from Seriola in 1974 in Japan, but different from ATCC 17911 isolated from white perch in USA. CONCLUSIONS: FF, BCM, FOM and ABPC were useful antimicrobials for treating pseudotuberculosis. However, the frequency of multidrug resistance was high. RAPD analysis showed homogeneity of isolates from Seriola in Japan. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that some antimicrobials were still useful for treating pseudotuberculosis and that P. damselae ssp. piscicida strains of same origin might have spread among Seriola in Japan since 1974.

Animals↗
PubMed2005

Drug resistance and pulsed-field gel electrophoresis patterns of Lactococcus garvieae isolates from cultured Seriola (yellowtail, amberjack and kingfish) in Japan.

AIMS: To investigate the existing antimicrobial susceptibility and genetic characteristics of Lactococcus garvieae isolates from cultured Seriola in Japan. METHODS AND RESULTS: Minimum inhibitory concentrations (MICs) of 14 antimicrobial agents for 170 isolates were determined using the agar dilution method. Seventy-five isolates (44.1%) were simultaneously resistant to erythromycin (EM) (MIC>or=2 microg ml-1), lincomycin (LCM) (MIC>or=128 microg ml-1) and oxytetracycline (OTC) (MIC>or=4 microg ml-1). Resistance to EM was grouped as intermediate- and high-level resistant by MIC values. All resistant isolates possessed ermB and tet(S) genes. The number of different bands between pulsed-field gel electrophoresis patterns of 25 isolates and two ATCC strains (isolated in 1974), determined using two enzymes (ApaI and SmaI), did not exceed 3. CONCLUSIONS: The present resistance pattern observed with ermB and tet(S) is similar to that observed in previous reports. Moreover, the genetic characteristics of L. garvieae isolates from a wide area in Japan in 2002 and ATCC strains were closely related. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that EM-, LCM- and OTC-resistant isolates have been present for 15 years and that L. garvieae strains with same origin have spread among Seriola spp. in Japan since 1974.

Animals↗
PubMed2002

Effect of a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin on immune function in male NC/Nga mice.

Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces immunosuppression in humans and animals. However, the effect of TCDD on Th2-type immune responses such as allergic reactions has been unclear. Using NC/Nga mice that developed atopic dermatitis-like skin lesions with marked elevation in plasma of total IgE when bred under conventional conditions, we investigated the effects of a single oral dose of TCDD on immune responses. NC/Nga mice received a single oral dose (0 or 20 microg/kg body weight) of TCDD. On day 7, treatment with TCDD alone decreased the cellularity of thymus. However, treatment with TCDD modified the cellularity of spleens and mesenteric lymph nodes (MLNs) but not of the thymus on day 28. When NC/Nga mice received ip immunization with OVA and alum on the same day as the TCDD treatment (0, 5, or 20 microg/kg body weight), TCDD markedly suppressed the concentrations of Th2-type cytokines (e.g., IL-4 and IL-5) in culture supernatants of spleen cells, whereas IFN-gamma production significantly increased. TCDD exposure reduced anti-OVA and total IgE antibody titers in plasma and did not induce the development of atopic dermatitis-like lesions in the pinnae or dorsal skin of NC/Nga mice. These results suggest that in NC/Nga mice, exposure to TCDD may impair the induction of Th2-type immune responses.

Administration, Oral↗
PubMed2001

Antimicrobial susceptibilities of Erysipelothrix rhusiopathiae isolated from pigs with swine erysipelas in Japan, 1988-1998.

The susceptibility to 21 antimicrobial agents of 214 strains of Erysipelothrix rhusiopathiae isolated from pigs affected with swine erysipelas in Japan between 1988 and 1998 was determined. Ampicillin, cloxacillin, benzylpenicillin, ceftiofur, tylosin, enrofloxacin and danofloxacin were the most active agents [minimum inhibitory concentrations (MICs); < or = 0.025-0.78 microgram/ml], followed by cefazolin, virginiamycin, tiamulin, chloramphenicol, florphenicol and oxolinic acid (MICs; 0.1-25 micrograms/ml). Activity was poor or absent with kanamycin and sulfadimethoxine. Strains resistant to dihydrostreptomycin, erythromycin, clindamycin, lincomycin, oxytetracycline and doxycycline were detected. The susceptibilities to dihydrostreptomycin and oxytetracycline tended to decrease. Investigation of the differences in antimicrobial susceptibility of the 214 strains according to their serotypes, sources, isolation years and regions, showed that the strains resistant to dihydrostreptomycin were most frequently found in the strains of serotype 1a and in strains from septicaemic cases. Strains resistant to oxytetracycline were detected in all serotypes and all sources, and most of the strains resistant to erythromycin were detected in the strains of serotype 2. The frequency of strains resistant to dihydrostreptomycin gradually increased from 1988 to 1996, but then decreased between 1997 and 1998. The frequency of strains resistant to oxytetracycline was remained more than 38% from 1988 to 1998. It was suggested that the strains resistant to dihydrostreptomycin and oxytetracycline were distributed over almost all districts of Japan.

Animals↗
PubMed2001

Increased plasminogen activator inhibitor-1 and apolipoprotein (a) in coronary atherectomy specimens in acute coronary syndromes.

BACKGROUND: Although increased tissue factor expression is known in vulnerable plaques, there is no reported study to compare plaque fibrinolysis in stable and unstable plaques. This study investigates the extent of plasminogen activator inhibitor-1 (PAI-1) and apolipoprotein (a) [apo(a)] in the plaques of different types of coronary artery disease as well as the correlation between these molecules and infiltration of macrophages to plaques. METHODS: Using immunohistochemical staining, we examined PAI-1 expression and apo(a) deposition in coronary atherosclerotic specimens obtained by directional coronary atherectomy from 19 patients with acute myocardial infarction (AMI), 12 with unstable angina pectoris (UAP), and 13 with stable angina pectoris (SAP). The percentages of the total areas of specimens stained with PAI-1 or apo(a) were estimated by an NIH image program. The proportion of macrophages as a percentage of all cells in plaques was calculated as the macrophage density. RESULTS: We found significantly higher percentages of total areas of specimens stained with PAI-1 in AMI (25.5 +/- 8.6%, P < 0.001) and UAP (22.2 +/- 10.4%, P < 0.005) than in SAP (9.5 +/- 5.0%), as well as with apo(a) (AMI; 11.7 +/- 7.1%, P < 0.005, UAP; 11.1 +/- 5.5%, P < 0.01 versus SAP; 3.9 +/- 1.5%). Linear regression analysis of all the samples showed a correlation between PAI-1 or apo(a) and macrophage density (PAI-1: r = 0.75, P < 0.001 and apo(a): r = 0.56, P < 0.001). CONCLUSIONS: Our results suggest a possible contribution of increased PAI-1 and apo(a) in plaques to the pathogenesis of acute coronary syndromes including impaired fibrinolysis.

Aged↗
PubMed2000

The effects of perinatal exposure to low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin on immune organs in rats.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is revealed to exert diverse biological effects including immunotoxicity, mainly by inadvertently activating the transcription factor arylhydrocarbon receptor (AhR). In the present study, the developmental effects of perinatal exposure to low doses of TCDD on the major immune organs of offspring, thymus and spleen, were investigated focusing on weaning time (postnatal day (PND) 21), puberty (PND 49) and adulthood (PND 120) in male rats. Concurrently, TCDD contents in those organs were measured with a high-resolution gas chromatography-mass spectrometry (GC/MS). In the thymus and spleen, CYP1A1 mRNA induction, the sensitive reaction caused by activation of AhR, was also measured in order to examine whether perinatally administered TCDD can elicit gene expressions in these organs. When pregnant dams were administered a single oral dose of 12.5-800 ng TCDD/kg body weight on gestation day (GD) 15, the weights of the thymus and spleen of the offspring did not differ from those of control animals throughout the experiments. The thymus and spleen maternally exposed to 800 ng TCDD/kg contained 102.0 and 62.7 pg TCDD/g tissue on PND 21, respectively, and the amounts decreased thereafter. In the thymus, dose-dependent CYP1A1 mRNA induction was clearly observed by maternal exposure to 50-800 ng TCDD/kg on PND 5. The induction was gradually decreased on PND 21 and 49. On the other hand, CYP1A1 mRNA induction in the spleen was very weak. In these thymi, no reproducible change was observed by TCDD exposure in cell number and cellular population defined by CD4 and CD8 molecules at any time. In contrast, splenocyte number was shown to decrease by maternal exposure to 12.5-800 ng TCDD/kg in a dose-dependent manner on PND 49. The alteration in spleen cellularity by TCDD was not detected on PND 21 or 120. These results clarified that perinatal exposure to low doses of TCDD affects the immune organs, which is apparent in spleen around puberty and likely to be hardly relevant to AhR-dependent gene expressions.

Animals↗
PubMed2000

Cloning and expression of a gene encoding the flagellin of Clostridium chauvoei.

Clostridium chauvoei is a causative agent of blackleg and the major protective antigen of the organism is the flagellar protein. Using an Escherichia coli expression library of the C. chauvoei Okinawa strain, we isolated the fliC gene encoding the flagellin protein. DNA sequence analysis revealed an open reading frame of 413 amino acid residues with a calculated molecular mass of 43819Da. Comparison of the sequence with those of flagellins from other bacteria showed considerable homology in the N-terminal and C-terminal domains. The glutathione-S-transferase (GST)-flagellin fusion protein and the purified FliC protein after removing the GST part with thrombin reacted with both polyclonal antisera and the non-protective monoclonal antibody (Mab), Mo-114. However, the protective Mab, Mo-41, which may recognize its conformational epitope, failed to react with both the GST-flagellin fusion protein and the purified FliC. Furthermore, the GST-flagellin fusion protein and the purified FliC induced very little protective immunity in mice. These results suggested that a conformation-dependent epitope play an important role in the development of immunity against blackleg.

Animals↗
PubMed2000

Alterations of thymocyte development, thymic emigrants and peripheral T cell population in rats exposed to 2,3,7, 8-tetrachlorodibenzo-p-dioxin.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exerts diverse biological effects by activating the cytosolic transcription factor, arylhydrocarbon receptor (AhR), which translocates to nuclei by TCDD binding and induces gene expressions. Among the well known-adverse effects of TCDD is thymus atrophy. In thymus atrophy, TCDD alters the proliferation as well as the differentiation of immature thymocytes. Previous studies on the effects of TCDD on thymocyte development were primarily carried out with high doses of TCDD. The present study investigates the effects of lower doses of TCDD (1 or 2 microg TCDD/kg by gavage) on thymocyte development, and furthermore, their sequential consequences on the peripheral T cell repertoire. Seven days after treatment with 1 or 2 microg TCDD/kg, the expression of CYP1A1 mRNA, one of the sensitive responses caused by the binding of TCDD to AhR, was detected in the thymus of rats. Thymus weights and thymus cell numbers decreased in TCDD-treated rats in a dose-dependent manner. The ratios of CD4 single-positive (SP) cells/CD8 SP cells were significantly reduced by TCDD exposure, indicating that the maturation of CD4(+)CD8(+) double-positive (DP) cells was skewed toward CD8 SP cells. These changes in the thymus were parallel to those previously observed with high doses of TCDD exposure. However, the specific reduction of DP cells reported in previous studies with high doses of TCDD was not detected in the present study. On the other hand, the skewing of mature CD4/CD8 T cell ratio in thymocytes by TCDD was not reflected in mesenteric lymph node (LN) lymphocytes, where the proportion of CD8 T cells was rather lowered by TCDD with a significant difference at 1 microg TCDD/kg. In LN lymphocytes, the percentage of recent thymic emigrants (RTEs), defined by the surface markers of Thy1(+)CD45RC(-), was shown to be significantly reduced by exposure to 1 and 2 microg TCDD/kg. T cell supply from the thymus has a crucial role in keeping the diversity of the T cell repertoire. The results of the present study indicated that lower doses of TCDD affect thymocyte development, especially differentiation, and reduce the proportion of RTE in LN, which may cause immunosuppression by reducing the variety of the T cell receptor repertoire.

Animals↗
PubMed2000

Morphology of vulnerable coronary plaque: insights from follow-up of patients examined by intravascular ultrasound before an acute coronary syndrome.

OBJECTIVES: To determine the morphologic features of coronary plaques associated with acute coronary syndrome, we prospectively followed patients with atherosclerotic disease identified by intravascular ultrasound (IVUS). BACKGROUND: Although clinical evaluation of the vulnerable atherosclerotic plaque is important, few data exist regarding the morphology of the vulnerable plaque in clinical settings. METHODS: We examined 114 coronary sites without significant stenosis by angiography (<50% diameter stenosis) in 106 patients. All the sites exhibited atherosclerotic lesions by IVUS. These lesions consisted of 22 concentric and 92 eccentric plaques with a percent plaque area averaging 59 +/- 12%. RESULTS: During the follow-up period of 21.8 +/- 6.4 months (range 1 to 24), 12 patients had an acute coronary event at a previously examined coronary site at an average of 4.0 +/- 3.4 months after the initial IVUS study. All the preexisting plaques related to the acute events exhibited an eccentric pattern and the mean percent plaque area was 67 +/- 9%, which was greater than plaque area in the other 90 patients without acute events (57 +/- 12%, p < 0.05). There was no statistically significant difference in lumen area between two patient groups (6.7 +/- 3.0 vs. 7.5 +/- 3.7 mm2). Among 12 coronary sites with an acute occlusion, 10 sites contained the echolucent zones, eight of these shallow and two deep, likely representing a lipid-rich core. In 90 sites without acute events, an echolucent zone in the shallow portion was seen at only four sites (p < 0.05). CONCLUSIONS: Large eccentric plaque containing an echolucent zone by IVUS can be at increased risk for instability even though the lumen area is preserved at the time of initial study. Compensatory enlargement of vessel wall due to remodeling may contribute to the relatively small degree of stenosis by angiography.

Angina Pectoris↗
PubMed2000

Taxonomic evidence that serovar 7 of Erysipelothrix strains isolated from dogs with endocarditis are Erysipelothrix tonsillarum.

The levels of relatedness among strains of Erysipelothrix serovar 7 isolated from dogs with endocarditis were estimated by performing DNA-DNA hybridization experiments with the type strains of Erysipelothrix rhusiopathiae and Erysipelothrix tonsillarum. All the canine strains exhibited more than 81% hybridization with the type strain of E. tonsillarum but less than 13% hybridization with the type strain of E. rhusiopathiae. Based on DNA-DNA hybridization results we confirmed that serovar 7 of the isolates from dogs with endocarditis were conclusively identified as E. tonsillarum. These results strongly indicate that some strains of genomic E. tonsillarum are a canine pathogen.

Animals↗
PubMed2000

Influence of antibiotics used as feed additives on the immune effect of erysipelas live vaccine in swine.

To investigate the influence of antibiotics used as feed additives on the immune response to erysipelas live vaccine, the pig inoculation test was applied. Avilamycin, oxytetracycline quaternary salt, enramycin, virginiamycin and tylosin phosphate were selected as test antibiotics. Five experimental feeds containing each antibiotic at the highest concentration permitted for feed additives in Japan, and the basal diet lacking antibiotics were examined. Twenty-nine pigs were divided into six groups. At first all the groups were fed with the antibiotic-free basal diet for 7 days, and then each group received the experimental feeds. On the 14th day after feeding with test feeds all the pigs, except for one control pig in each group, were immunized with the vaccine and all the pigs were then challenge-exposed to a virulent strain of Erysipelothrix rhusiopathiae 14 days after vaccination. The clinical response was observed every day for 14 days. In all the groups, most of the vaccinated pigs did not develop any clinical signs of acute erysipelas after the challenge exposure, whereas non-vaccinated control pigs died or showed severe generalized erythema with profound depression and anorexia. No differences in the protection against the challenge exposure were observed among the groups. Therefore, the present results suggest that these selected antibiotics would not interfere with the immune effect of the vaccine if given at the usual concentrations used for feed additives.

Animal Feed↗
PubMed2000

mkp-1 encoding mitogen-activated protein kinase phosphatase 1, a verotoxin 1 responsive gene, detected by differential display reverse transcription-PCR in Caco-2 cells.

The major cytotoxic effect of the verotoxins (VTs) produced by strains of VT-producing Escherichia coli is the inhibition of host-cell protein synthesis, but VTs are also suspected to play a role in apoptotic cell signaling and cytokine release. Four differentially expressed genes, including mkp-1 (encoding mitogen-activated protein kinase phospatase 1), were detected by differential display reverse transcription-PCR (DD RT-PCR) stimulated by VT1 in Caco-2 cells. Northern blot analysis showed the induction of mkp-1 mRNA 6 h after VT1 stimulation. Neither mutant VT1 (mutVT1), harboring two mutations in the A subunit (E167Q-R170L), nor cycloheximide induced mkp-1 mRNA, but mkp-1 mRNA was detected with both wild-type VT1 (wtVT1) and anisomycin, a 28S rRNA inhibitor. Therefore, we concluded that the A subunit of VT1 was essential for mkp-1 induction. Increased amounts of phosphorylated c-Jun protein were also found with wtVT1 and anisomycin. Although the precise mechanism of induction of MKP-1 is unknown, we hypothesized that 28S rRNA not only was a sensor for ribotoxic stress, but also was involved in the signal cascade of MKP-1. This is the first report of detection by DD RT-PCR of cellular genes induced by bacterial toxins.

Animals↗
PubMed2000

Extraocular muscle responses to high dose intravenous methylprednisolone in myasthenia gravis.

Three patients with generalised myasthenia gravis and three with ocular myasthenia gravis received two to five courses of high dose intravenous methylprednisolone because of the failure of standard immunomodulating therapies. Changes in myasthenic signs were assessed using a four step system for grading muscle weakness and fatiguability in 10 test items. Although a brief and modest amelioration was found from day 1 to day 2 after the initial infusion in two patients with generalised myasthenia gravis, all three experienced a prolonged phase of worsening followed by improvement before the next course. Conversely, for two of the patients with ocular myasthenia gravis, a transient but dramatic improvement of ptosis and ocular immobility was noted from 90 minutes to 5 hours after initiating the first infusion, followed by mild or no exacerbation. This 3 hour improvement may be related not only to possible differences in the neuromuscular junction, but also to corticosteroids unmasking the central adaptation for the peripheral ocular muscle weakness by increasing the acetylcholine release.

Acetylcholine↗
PubMed2000

Modulation of swallowing reflex by lung volume changes.

We investigated the effects of changes in lung volume on coordination of respiration and swallowing in 11 healthy subjects. Swallowing reflexes were elicited by bolus injections of a small amount of distilled water (1 ml) and by continuous infusion of distilled water (3 ml/min) into the pharynx at three different levels of lung volume. The lung volume was changed by application of negative extrathoracic pressure (0, -20, and -40 cm H(2)O). We found that increases in lung volume prolonged the latency of swallows elicited by bolus injection of water and decreased the number of swallows during continuous infusion of water. In addition, the preponderant coupling of swallows with the expiratory phase observed before application of negative extrathoracic pressure was lost during application of negative extrathoracic pressure. These results may indicate that lung inflation has an inhibitory influence on the swallowing reflex, and modulates the timing of swallowing in reference to the respiratory cycle.

Adult↗
PubMed1999

Learning to design synergetic computers with an extended symmetric diffusion network.

This article proposes an extended symmetric diffusion network that is applied to the design of synergetic computers. The state of a synergetic computer is translated to that of order parameters whose dynamics is described by a stochastic differential equation. The order parameter converges to the Boltzmann distribution, under some condition on the drift term, derived by the Fokker-Planck equation. The network can learn the dynamics of the order parameters from a nonlinear potential. This property is necessary to design the coefficient values of the synergetic computer. We propose a searching function for the image processing executed by the synergetic computer. It is shown that the image processing with the searching function is superior to the usual image-associative function of synergetic computation. The proposed network can be related, as a special case, to the discrete-state Boltzmann machine by some transformation. Finally, the extended symmetric diffusion network is applied to the estimation problem of an entire density function, as well as the proposed searching function for the image processing.

Artificial Intelligence↗