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H Kawamoto

Publications and source records attributed to H Kawamoto.

At least 19 recordsLinked to original sources
PubMed2002

Development of a combined filtration-enrichment culture followed by a one-step duplex PCR technique for the rapid detection of Campylobacter jejuni and C. coli in human faecal samples.

A new combined filtration-enrichment culture followed by a PCR technique for the rapid detection of Campylobacterjejuni and C. coli in human faeces has been developed. Only bacteria that passed through the membrane could multiply in the enrichment culture; target bacteria were detected by a one-step duplex PCR technique with combinations of primers that are specific for different Campylobacter spp., which should allow for the detection of a mixed infection in a single patient. A Falcon cell-culture insert and 24-well tissue-culture plates were used. After 2 days, both C. jejuni and C. coli were reliably detected in diluted faeces that were seeded with as few as 10 cells which corresponds to a concentration of 10(3) cfu/g. Even allowing for the dilution of faecal samples, this represents an increase in sensitivity of two-to-three orders of magnitude over the conventional filtration method.

Campylobacter coli↗
PubMed2001

Characterization of Norwalk virus GI specific monoclonal antibodies generated against Escherichia coli expressed capsid protein and the reactivity of two broadly reactive monoclonal antibodies generated against GII capsid towards GI recombinant fragments.

BACKGROUND: Norwalk virus causes outbreaks of acute non-bacterial gastroenteritis in humans. The virus capsid is composed of a single 60 kDa protein. In a previous study, the capsid protein of recombinant Norwalk virus genogroup II was expressed in an E. coli system and monoclonal antibodies were generated against it. The analysis of the reactivity of those monoclonal antibodies suggested that the N-terminal domain might contain more antigenic epitopes than the C-terminal domain. In the same study, two broadly reactive monoclonal antibodies were observed to react with genogroup I recombinant protein. RESULTS: In the present study, we used the recombinant capsid protein of genogroup I and characterized the obtained 17 monoclonal antibodies by using 19 overlapping fragments. Sixteen monoclonal antibodies recognized sequential epitopes on three antigenic regions, and the only exceptional monoclonal antibody recognized a conformational epitope. As for the two broadly reactive monoclonal antibodies generated against genogroup II, we indicated that they recognized fragment 2 of genogroup I. Furthermore, genogroup I antigen from a patient's stool was detected by sandwich enzyme-linked immunosorbent assay using genogroup I specific monoclonal antibody and biotinated broadly reactive monoclonal antibody. CONCLUSION: The reactivity analysis of above monoclonal antibodies suggests that the N-terminal domain may contain more antigenic epitopes than the C-terminal domain as suggested in our previous study. The detection of genogroup I antigen from a patient's stool by our system suggested that the monoclonal antibodies generated against E. coli expressed capsid protein can be used to detect genogroup I antigens in clinical material.

Antibodies, Monoclonal↗
PubMed2001

Expression of alpha(4)beta(7) integrin defines a distinct pathway of lymphoid progenitors committed to T cells, fetal intestinal lymphotoxin producer, NK, and dendritic cells.

During embryogenesis, the Peyer's patch anlagen are induced by a cell population that produces lymphotoxin (LT) alpha(1)beta(2) following stimulation of IL-7Ralpha. In this study, we show that the LT-producing cell is localized within the IL-7Ralpha(+) and integrin alpha(4)beta(7) (alpha(4)beta(7))(+) population in the embryonic intestine. Lineage commitment to the LT producer phenotype in the fetal liver coincides with expression of alpha(4)beta(7). Before expression of alpha(4)beta(7), the potential of IL-7Ralpha(+) population to generate B cells is lost. However, the progenitors for T cells and LT producer cells reside in the IL-7Ralpha(+)alpha(4)beta(7)(+) cells, but during subsequent differentiation, the potential to give rise to T cells is lost. This IL-7Ralpha(+)alpha(4)beta(7)(+) population migrates to the intestine, where it induces the Peyer's patch anlagen. When stimulated with IL-15 or IL-3 and TNF, the intestinal IL-7Ralpha(+)alpha(4)beta(7)(+) population can differentiate into fully competent NK1.1(+) NK cells or CD11c(+) APCs. Expression of alpha(4)beta(7) is lost during differentiation of both lineages; IL-7Ralpha expression is lost during NK1.1(+) cells differentiation. A newly discovered lineage(-)IL-7Ralpha(+)c-Kit(+)alpha(4)beta(7)(+) population in the fetal liver is committed to T, NK, dendritic, and fetal intestinal LT producer lineage, the latter being an intermediate stage during differentiation of NK and dendritic cells.

Animals↗
PubMed2001

In vitro inhibitory effects of J-113397 on nociceptin/orphanin FQ-stimulated.

J-113397 (1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one) is a recently developed antagonist of the opioid receptor-like 1 (ORL1) receptor. We compared the in vitro functional profile J-113397 on [35S]guanosine 5'-O-(gamma-thio)triphosphate (GTPgammaS) binding to mouse brain with that of [Phe1psi(CH2-NH)Gly2]nociceptin(1-13)NH2 and naloxone benzoylhydrazone (NalBzoH). J-113397 antagonized nociceptin/orphanin FQ-stimulated [35S]GTPgammaS binding to mouse brain with an IC50 value of 7.6 nM, but had no effect on basal [35S]GTPgammaS binding by itself. [Phe1psi(CH2-NH)Gly2]nociceptin(1-13)NH2 partially antagonized nociceptin/orphanin FQ-stimulated [35S]GTPgammaS binding but showed agonistic activity on ORL1 by itself. NalBzoH showed antagonistic activity on ORL1 receptor but had significant agonistic activity on other opioid receptors at lower doses. Schild plot analysis demonstrated competitive antagonism of J-113397 on ORL1 receptor in mouse brain. A [35S]GTPgammaS binding study using ORL1 receptor-deficient mice confirmed the selective antagonism of J-113397 on ORL1 receptor. These data indicate that J-113397 is the most potent and selective antagonist of ORL1 receptor in mouse brain that has yet been reported, and therefore will be a useful tool for characterization of ORL1 receptors in the brain.

Animals↗
PubMed2001

Commitment to natural killer cells requires the helix-loop-helix inhibitor Id2.

We have previously described how T and natural killer (NK) lineage commitment proceeds from common T/NK progenitors (p-T/NK) in the murine fetal thymus (FT), with the use of a clonal assay system capable of discriminating p-T/NK from unipotent T or NK lineage-committed progenitors (p-T and p-NK, respectively). The molecular mechanisms controlling the commitment processes, however, are yet to be defined. In this study, we investigated the progenitor activity of FT cells from Id2-/- mice that exhibit defective NK cell development. In the Id2-/- FT, NK cells were greatly reduced, and a cell population that exclusively contains p-NK in the wild-type thymus was completely missing. Id2-/- FT progenitors were unable to differentiate into NK cells in IL-2-supplemented-FT organ culture. Single progenitor analysis demonstrated that all Id2-/- fetal thymic progenitors are destined for the T cell lineage, whereas progenitors for T/NK, T, and NK cell lineages were found in the control. Interestingly, the total progenitor number was similar between Id2-/- and Id2+/+ embryos analyzed. Expression of Id2 was correlated with p-NK activity. Our results suggest that Id2 is indispensable in thymic NK cell development, where it most probably restricts bipotent T/NK progenitors to the NK cell lineage.

Animals↗
PubMed2001

Immobilization of cycloisomaltooligosaccharide glucanotransferase for the production of cycloisomaltooligosaccharides from dextran.

Immobilization of cycloisomaltooligosaccharide glucanotransferase (CITase) and its application in the production of cycloisomaltooligosaccharides (CIs) from dextran were studied. Among various carrier materials examined, the enzyme adsorbed physically on Chitopearl BCW-3505 showed the highest activity (1.75 U/ml carrier). The activity remaining was 35%. The maximum CI yield in batch reactions at 0.2, 2 and 10% dextran was 28, 24 and 12%, respectively. The maximum CI yield at 2% dextran (24%) was slightly less than that with the free enzyme under the same conditions (26%). The concentration of linear oligosaccharides, the byproducts in the reaction mixture, was greater with the immobilized CITase than the free enzyme. The immobilized CITase was less thermostable than the free enzyme by about 10 degrees C. The pattern of influence of Ca(2+) concentration on the thermostability differed between the free and immobilized CITase. A Ca(2+) concentration of 50-100 mM was optimum for the thermostability of the immobilized CITase, 10-50 mM for the free enzyme. CIs were produced continuously by a column system packed with the immobilized enzyme at 40 degrees C with a space velocity (SV) of 6 h(-1). The three quarters life time was 4 weeks. We think that relatively long life time at fast SV was accomplished and CI production cost by this method should be lower than the batch reaction. This is the first report on immobilization of CITase.

Journal Article↗
PubMed2001

Immature multipotent hemopoietic progenitors lacking long-term bone marrow-reconstituting activity in the aorta-gonad-mesonephros region of murine day 10 fetuses.

Previous studies indicated that multipotent progenitors exist in early fetuses that do not contain long-term reconstituting (LTR) activity. However, it remained unclear whether these multipotent progenitors are committed to the hemopoietic lineage or are immature mesodermal cells or hemangioblasts. In this study, we have succeeded in enriching the multipotent progenitors that are capable of generating myeloid, T, and B cells in the LFA-1(-) subpopulation of TER-119(-)c-kit(+)CD45(+) cells from the aorta-gonad-mesonephros (AGM) region of day 10 fetuses. We found that these day 10 AGM LFA-1(-) cells do not show the LTR activity, whereas day 11 AGM LFA-1(-) cells do have such an activity. These results strongly suggest that multipotent progenitors lacking LTR activity emerge as CD45(+) hemopoietic progenitor cells in the AGM region on the 10th day of gestation, and such p-Multi mature into hemopoietic stem cells by acquiring LTR activity.

Animals↗
PubMed2001

Ultrasonographic characteristics of thyroid nodules: prediction of malignancy.

BACKGROUND: High-resolution real-time ultrasonography (US) can detect characteristics of thyroid nodules, but the US differentiation between malignant nodules and benign nodules is not well described. HYPOTHESIS: Ultrasonography is useful for predicting malignancy of thyroid nodules. DESIGN: A retrospective study of 329 thyroid nodules (> or =5 mm) in 309 patients comparing US characteristics and pathological results. SETTING: A center for the treatment of thyroid diseases where about 1400 thyroid operations are performed per year. PATIENTS: Between January 1 and June 30, 1999, 309 patients were examined by US before thyroidectomy. MAIN OUTCOME MEASURE: The US characteristics to predict malignancy for both follicular and nonfollicular neoplasms by means of multiple logistic regression analysis. RESULTS: The sensitivity of preoperative US diagnosis was 86.5% for nonfollicular neoplasms and 18.2% for follicular neoplasms. The specificity was 92.3% and 88.7%, respectively. According to multiple logistic regression analysis, margin, shape, echo structure, echogenicity, and calcification were reliable indication of malignancy in nonfollicular neoplasms. According to a receiver operating characteristic curve constructed from this multiple logistic regression analysis, the best point not to overlook malignancy is the point at which sensitivity is 94% and specificity is 87%. The probability of malignancy at this point is greater than 0.2. For follicular neoplasms, ultrasonographic diagnosis was unreliable, even when multiple logistic regression analysis was applied. CONCLUSION: We can predict malignancy of nonfollicular neoplasms of the thyroid by using multiple logistic regression analysis based on only 5 features: margin, shape, echo structure, echogenicity, and calcification.

Adolescent↗
PubMed2001

Nucleotide sequence analysis and development of consensus primers of RT-PCR for detection of Norwalk-like viruses prevailing in Japan.

A total of 177 different nucleotide sequences of the RNA polymerase region of Norwalk-like viruses (NLVs) genomes, collected via a nation-wide survey project in Japan between 1989 and 1998, were examined by reverse transcription-polymerase chain reaction (RT-PCR) employing various primer pairs. The nucleotide sequences of different strains showed great diversity, with a range of 57 to 100% identities among strains. The strains could be classified into five clusters: Norwalk (NV), Snow Mountain agent/Bristol virus (SMA/BV), Toronto virus/Mexico virus (TV/MX), and Japan specific cluster 1 and 2 (JP-1 and JP-2). Within each cluster there is greater than 85% identity of amino acid sequence (more than 75% identity of nucleotide sequences), based on sequence homology analysis. We believe that two of the five clusters, JP-1and JP-2, define new specific clusters found in Japan according to phylogenetic and pair-wise comparison studies. An RT-PCR procedure was designed using new consensus primer pairs, P1/P2, P1/P3, and Y1/Y2 based on multiple alignment of collected nucleotide sequences, that are expected to detect nearly all NLVs prevailing in Japan. The usefulness of the primers was tested by ten different laboratories in Japan using a panel of ten fecal samples containing different virus strains. The identification of these primer pairs will facilitate routine diagnosis of NLV infection by RT-PCR and offers the potential for their direct detection in food and environmental samples.

Caliciviridae Infections↗
PubMed2001

A novel missense mutation in human lactate dehydrogenase B-subunit gene.

Reduced activity of serum lactate dehydrogenase (LDH; EC 1.1.1.27) was found in a male medical student during practical examinations of his own blood. Serum LDH isoenzyme pattern showed reductions in activities of the isoenzymes with lower subunit A/B ratios such as LDH1 and LDH2. These findings were indicative of a partial LDH-B subunit deficiency, which was confirmed in erythrocyte hemolysates by Western blotting. Polymerase chain reaction (PCR)-based DNA sequence analysis of the LDH-B subunit gene revealed a heterozygous nucleotide change: a guanine to adenine substitution in codon 69 (GGG --> GAG) at the third exon of the LDH-B subunit gene that resulted in a glycine to glutamic acid substitution (G69E). The mutation was confirmed by PCR-restriction fragment length polymorphism (RFLP) analysis using a mismatched primer to introduce a new NcoI restriction site. The same heterozygous mutation was found in his mother but not in other family members. This mutation involves a residue belonging to alphaC helix in LDH-B subunit protein molecule that functions as an interface for other subunits.

Adult↗
PubMed2001

A modified burr-hole method in galeoduroencephalosynangiosis for an adult patient with probable moyamoya disease--case report and review of the literature.

A 49-year-old woman with probable moyamoya disease was surgically treated by combined direct and indirect methods, superficial temporal to middle cerebral artery anastomosis and galeoduroencephalosynangiosis by a burr-hole method developed by Kawamoto et al. Transient ischemic attacks and motor weakness of bilateral lower extremities disappeared completely within 1 month and never recurred during 1-year follow-up. Galeoduroencephalosynangiosis by a burr-hole method appears useful for preventing ischemic damage of the territory of the anterior cerebral artery in adult patients with probable moyamoya disease.

Anastomosis, Surgical↗
PubMed2001

Predictive risk factors for postoperative tetany in female patients with Graves' disease.

BACKGROUND: Postoperative tetany occurs in patients with secondary hyperparathyroidism caused by a deficiency in calcium and vitamin D concomitant with transient hypoparathyroidism induced by surgery. In the present study, we further clarified the risk factors by referring to serum 25-hydroxyvitamin D [25(OH)D] and alkaline phosphatase. STUDY DESIGN: The serum levels of intact parathyroid hormone, calcium and other electrolytes, and 25-hydroxyvitamin D [25(OH)D] were measured preoperatively in 178 female patients with Graves' disease who underwent subtotal thyroidectomy. RESULTS: Of the 178 female patients, 15 (8.4%) developed tetany. Univariate analysis of 16 possible risk factors showed that 2 were statistically significant: serum 25(OH)D and alkaline phosphatase levels. The incidence of tetany according to the serum levels of 25(OH)D and alkaline phosphatase was 19.1% (9/47) in patients with 25(OH)D < or = 25 nmol/L and alkaline phosphatase > 155, 11.8% (4/34) in those with 25(OH)D < or = 25 nmol/L and alkaline phosphatase < or = 155, 6.7% (2/30) in those with 25(OH)D > 25 nmol/L and alkaline phosphatase > 155, and 0% (0/50) in those with 25(OH)D > 25 nmol/L and alkaline phosphatase < or = 155. CONCLUSIONS: Patients with Graves' disease who have vitamin D deficiency with high serum alkaline phosphatase levels are the highest-risk group for postoperative tetany. Serum 25(OH)D and alkaline phosphatase should be monitored in patients with Graves' disease.

Adolescent↗
PubMed2001

The earliest stages of B cell development require a chemokine stromal cell-derived factor/pre-B cell growth-stimulating factor.

Environmental factors essential for the first stages of B lymphopoiesis remain elusive. Here, we report that immediately after commitment to B lineage, precursors become dependent on a chemokine SDF-1 and its receptor CXCR4 using mutant and radiation chimeric mice. In bone marrow, generation of the earliest identifiable B cell precursor populations requires CXCR4. In fetal liver, we identified Lin(-)CD19(-)c-kit(+)IL-7Ralpha(+)AA4.1(+), the earliest unipotent B cell precursor population, and found that its development was severely affected in SDF-1(-/-) embryos but not in IL-7(-/-) embryos. Lin(-) T cell progenitors appeared normal in SDF-1(-/-) embryos. Moreover, SDF-1 exhibited specific biologic activities on the earliest B cell precursors. SDF-1 provides the first example of a cytokine responsible for the earliest B lineage stages.

Animals↗
PubMed2001

Effect of combining ultrasonography and ultrasound-guided fine-needle aspiration biopsy findings for the diagnosis of thyroid nodules.

OBJECTIVE: To assess the accuracy of ultrasonography and cytology in predicting malignancy in thyroid nodules. DESIGN: Prospective open study. SETTING: Thyroid centre, Japan. SUBJECTS: 329 nodules in 309 patients examined by a new ultrasound scanner and ultrasound-guided fine-needle aspiration biopsy. INTERVENTIONS: Comparison of ultrasonographic, cytological, and combined diagnosis with the histological diagnosis. MAIN OUTCOME MEASURES: Sensitivity, specificity, and accuracy of each diagnostic method. RESULTS: The sensitivity, specificity, accuracy were 84%, 87%, 85% for cytological diagnosis, and 82%, 91%, and 87% for ultrasonographic diagnosis. By using ultrasonographic diagnosis when cytological specimens were inadequate or gave false negative results, the sensitivity, specificity, and accuracy went up to 89%, 91%, and 90%, respectively. We could not diagnose follicular carcinomas accurately by combined cytology and ultrasonography. CONCLUSION: The combination of ultrasonography and cytology improves the accuracy of diagnosis of thyroid nodules, but is less effective with follicular tumours.

Adolescent↗
PubMed2001

Progression of T cell lineage restriction in the earliest subpopulation of murine adult thymus visualized by the expression of lck proximal promoter activity.

The proximal promoter of lck directs gene expression exclusively in T cells. To investigate the developmental regulation of the lck proximal promoter activity and its relationship to T cell lineage commitment, a green fluorescence protein (GFP) transgenic (Tg) mouse in which the GFP expression is under the control of the proximal promoter of lck was created. In the adult GFP-Tg mice, >90% of CD4(+)CD8(+) and CD4(+)CD8(-) thymocytes, and the majority of CD4(-)CD8(+) and CD4(-)CD8(-) [double-negative (DN)] thymocytes were highly positive for GFP. Slightly lower but substantial levels of expression of GFP was also observed in mature splenic T cells. No GFP(+) cells was detected in non-T lineage subsets, including mature and immature B cells, CD5(+) B cells, and NK cells, indicating a preserved tissue specificity of the promoter. The earliest GFP(+) cells detected were found in the CD44(+)CD25(-) DN thymocyte subpopulation. The developmental potential of GFP(-) and GFP(+) cells in the CD44(+)CD25(-) DN fraction was examined using in vitro culture systems. The generation of substantial numbers of alphabeta and gammadelta T cells as well as NK cells was demonstrated from both GFP(-) and GFP(+) cells. However, no development of B cells or dendritic cells was detected from GFP(+) CD44(+)CD25(-) DN thymocytes. These results suggest that the progenitors expressing lck proximal promoter activity in the CD44(+)CD25(-) DN thymocyte subset have lost most of the progenitor potential for the B and dendritic cell lineage. Thus, progression of T cell lineage restriction in the earliest thymic population can be visualized by lck proximal promoter activity, suggesting a potential role of Lck in the T cell lineage commitment.

Animals↗
PubMed2001

Two distinct steps of immigration of hematopoietic progenitors into the early thymus anlage.

Thymic epithelial cells, which create a three-dimensionally organized meshwork structure peculiar to the thymus, develop from simple epithelia of the third pharyngeal pouch and cleft during organogenesis. We comparatively investigated the thymus anlages of normal and nude mice by immunohistochemical analysis with regard to epithelial organization and distribution of hematopoietic progenitor cells at early stages of organogenesis. Our results show that development of the mouse thymus anlage at early stages can be subdivided into at least two stages by the differences in epithelial organization, i.e. stratified epithelial stage on embryonic day (Ed) 11 and clustered epithelial stage on Ed12. At the former stage, hematopoietic progenitor cells are accumulated in the mesenchymal layer of the thymus anlage, and at the latter stage progenitor cells enter the epithelial cluster and proliferate. In nude mice, hematopoietic progenitor cells are found in the mesenchymal layer on Ed11.5, but they are not observed among epithelial cells on Ed12, even though epithelial cells form a cluster structure. The present results suggest that aberrant development of the nude mouse thymus anlage occurs at the clustered epithelial stage and that epithelial cells of the nude anlage lack the ability to induce the entrance of hematopoietic progenitor cells into the epithelial cluster.

Animals↗
PubMed2001

Perioperative transcranial Doppler US to evaluate intracranial compliance in young children undergoing craniosynostosis repair surgery.

PURPOSE: To determine whether measurements with transcranial Doppler ultrasonography (US) of resistive indexes (RIs) of basal cerebral arteries with pressure provocation can be used to identify infants and children with craniosynostosis who have abnormal intracranial compliance and to study the effects of surgery on compliance. MATERIALS AND METHODS: Transcranial Doppler US was performed through the temporal squama, fontanels, and existing skull defects prior to and immediately following cranioplasty. Twenty-four studies were performed in six patients with multisuture synostosis, and 61 studies were performed in 26 patients with single-suture synostosis. Study findings were compared with those of 23 control subjects and were characterized as normal or abnormal on the basis of age-specific normal criteria for RI. RESULTS: In multisuture synostosis, results of six of the nine preoperative transcranial Doppler US studies were abnormal. During postoperative follow-up, three recurrences requiring reoperation occurred, one of which was detected with abnormal transcranial Doppler US findings. In single-suture synostosis, results of seven of the 26 preoperative transcranial Doppler US studies were abnormal, and all occurred in young infants with sagittal and unicoronal synostosis. Immediate effects of surgery were variable. All patients with sagittal synostosis had a significant immediate postoperative increase in RI, which normalized during postoperative follow-up. There was no significant difference in RI between patients with successfully treated craniosynostosis and control subjects. CONCLUSION: Transcranial Doppler US can be used to identify patients with craniosynostosis with decreased intracranial compliance, and it is a suitable noninvasive test to monitor the effects of surgery on compliance.

Child, Preschool↗