Biomedical subjects

S Kato

Publications and source records attributed to S Kato.

At least 37 records · Page 2Linked to original sources

PubMed2005

Influence of age and duration of infection on bacterial load and immune responses to Helicobacter pylori infection in a murine model.

Using a murine model, we previously showed that Helicobacter pylori infects and colonizes offspring via maternal transmission during the nursing period. The aim of this study was to investigate the influence of age and duration of infection on inflammatory and immune responses to H. pylori in infant and adult mice. During the breast-feeding period, the number of bacteria was significantly suppressed in 1-week-old mice infected with H. pylori at an early stage of nursing, compared with adult mice, suggesting that breast-milk induces such low colonization. In addition, these mice had weaker gastric inflammation, especially Th1 cytokine and humoral responses than in mice infected with H. pylori after weaning in spite of elevated levels of Th1 cytokines. Although infant mice showed low inflammatory responses against H. pylori, they produced H. pylori-specific antibodies following vaccination with oral or parenteral adjuvant. Our results suggest the importance of age at the time of primary infection on bacterial load, gastric inflammation and humoral responses in a murine model of H. pylori infection.

Aging↗

PubMed2005

Development and characterization of human constitutive proteasome and immunoproteasome subunit-specific monoclonal antibodies.

Delta (Y), MB1 (X), and Z are the three catalytic beta-subunits located in the inner rings of the constitutive proteasome, an intracellular multicatalytic complex responsible for the generation of peptides presented by human leukocyte antigen (HLA) class I antigens to T cells. When cells are incubated with interferon-gamma, delta (Y), MB1 (X), and Z are replaced by LMP2, LMP7, and LMP10, respectively, leading to the expression of immunoproteasome which generates peptides with increased affinity for HLA class I antigens. The characterization of the expression of constitutive proteasome and immunoproteasome subunits in cells, normal tissues, and malignant lesions has been hampered by the lack or limited availability of constitutive proteasome and immunoproteasome subunit-specific monoclonal antibodies (mAbs), which are suitable for immunohistochemical staining. To overcome this limitation, we generated human delta (Y), MB1 (X), Z, LMP2, LMP7, and LMP10-specific mAb-secreting hybridomas from BALB/c mice immunized with peptides and recombinant fusion proteins. The mAbs SY-5, SJJ-3, NB-1, SY-1, HB-2, and TO-7 were shown to be specific for delta (Y), MB1 (X), Z, LMP2, LMP7, and LMP10, respectively, as they react specifically with the corresponding molecules when tested with a human B lymphoid LG2 cell lysate in Western blotting and with the peptide derived from each molecule in enzyme-linked immunosorbent assay. The reactivity of the six mAbs with the corresponding intracellular antigens resulted in intracellular staining when the mAbs were tested with microwave-treated and saponin-permeabilized cells in indirect immunofluorescence and with formalin-fixed, paraffin-embedded tissue sections in immunohistochemical reactions. These results suggest that the constitutive proteasome and immunoproteasome subunit-specific mAbs we have developed are useful probes to characterize the expression of proteasome subunits in normal tissues and in pathological lesions.

Animals↗

PubMed2005

Herpes simplex esophagitis in the immunocompetent host.

We report here a case of herpes esophagitis with Mallory-Weiss syndrome in an immunocompetent host. A 26-year-old man was admitted to our hospital because of common cold symptoms and eruptions on the body. On day 2 after hospitalization, the patient showed high-grade fever, odynophagia and hematemesis. Upper gastrointestinal endoscopic examination showed multiple ulcerations throughout the mid- and distal esophagus. Bleeding from a Mallory-Weiss tear was also seen. Follow-up endoscopic examinations showed whitish exudates on day 5. Histological examination of biopsy specimens showed Cowdry type A intranuclear inclusion bodies in epithelial cells. Positive staining of a specific antibody against herpes simplex virus-1 (HSV-1) was seen in the nuclei of esophageal epithelial cells. Primary HSV-1 infection was suspected because ELISA titers of serum IgM antibody against HSV-1 were high and titers of serum IgG antibody against HSV-1 increased from an almost cut-off ratio. A diagnosis of herpes esophagitis in an immunocompetent host was made. Our case is the first report of herpes esophagitis with Mallory-Weiss syndrome in the immunocompetent host. It is important to remind herpes esophagitis in cases of severe odynophagia even in immunocompetent hosts.

Adult↗

PubMed2005

The first grid for the oral and maxillofacial region and its application for speech analysis.

OBJECTIVES: Introduction of a new grid-based method for analyzing speech functions which takes into account the related information of patients' data and the oral air flow with pronouncing analyzed by computational fluid dynamics. METHODS: An on-line speech analyzer was developed for clinical use utilizing GridPort2.3.1 based on globus2.4.2, comprising several computational tools such as unified data storage, semantic data analysis, computational fluid dynamics analysis and three-dimensional visualization of calculated results from different hardware sources with various types of operation systems. RESULTS: The power transportation layer between dental clinics and computational and storage resources could be provided by using a WWW-based portal. The backend data management system could be constructed using a storage resource broker (SRB) and extensible mark up language (XML). CONCLUSIONS: The new method allows the construction of a data warehouse through this grid-based speech function analysis in order to extract the principal factors related to speech disorders.

Database Management Systems↗

PubMed2004

Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at Q2=0.92 and 1.76 GeV2.

We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.

Journal Article↗

PubMed2004

Does Vitamin D play a role on Msx1 homeoprotein expression involving an endogenous antisense mRNA?

Msx1 homeobox gene, a member of Msx family, has been implicated in numerous organs. Its participation was established in different events, such as morphogenetic field determinism and epithelio-mesenchymal interactions. Most of Msx1 target organs are also known for their sensitivity to Vitamin D: such as bone, tooth germ, and hair follicle. Whereas, the expression of Msx2, another member of Msx family, has been shown to be controlled by Vitamin D, no information is available for Msx1. This study aims to analyze the potential relationships between Vitamin D and Msx1 through: (1) comparative analysis of Vitamin D receptor (VDR) and Msx1 protein expression, (2) investigation of Msx1 expression in VDR null mutant mice, and (3) study of Msx1 overexpression impact on osteocalcin VDR expression in immortalized MO6-G3 odontoblasts. Results show the existence of cross-talks between Vitamin D and Msx1 regulation pathways. In odontoblastic cells, Msx1 overexpression decrease VDR expression, whereas in rickets Msx1 sense transcript expression is decreased. These cross-talks may open a new window in the analysis of rickets mineralized tissues physiopathology. In Vitamin D null mutants, the study of the natural Msx1 antisense transcript which has been recently described should be informative.

Animals↗

PubMed2004

Dental alveolar bone defects related to Vitamin D and calcium status.

Vitamin D is important for skeletal development, growth, and homeostasis but has been sparsely studied in the oro-facial bone. Dental alveolar bone anchors teeth to mandible and maxilla bones via a periodontal ligament. Its formation and maintenance are strictly dependent on the presence of tooth organs and it is characterized by a high turnover rate. In order to study the role of Vitamin D and the calcium status on dental alveolar bone formation, microradiographic and histologic comparison of wild-type, Vitamin D receptor null mutant (VDR (-/-) hypo- and normo-calcemic mice and tissues were performed at 2 months. In hypo-calcemic VDR (-/-) mice, alveolar bone was hypomineralized and demonstrated a cellular and matrix organization, similar to the immature woven bone. In normo-calcemic VDR (-/-) mice, mineralization of dental alveolar bone appeared normal, but bone was morphologically abnormal in some specific anatomical locations. These data show that Vitamin D and calcium status may control the formation of dental alveolar bone. The differences of phenotype between hypo- and normo-calcemic VDR null mutant mice suggested a specific Vitamin D control of alveolar bone formation by the Vitamin D nuclear receptor pathway.

Alveolar Process↗

PubMed2004

Allogeneic myeloablative transplantation for patients aged 50 years and over.

Allogeneic hematopoietic stem cell transplantation (HSCT) has been performed mainly for young patients due to concern about the high incidence of treatment-related mortality (TRM). Recent advances to reduce TRM by using peripheral blood stem cells or nonmyeloablative conditioning regimens have increased the age limit for this procedure, and correctly identifying the indication for transplant is essential for older patients. In this study, we analyzed data from 398 patients aged 50 or over selected from 5147 patients, who received conventional allogeneic HSCT (c-HSCT). Patients aged 50 or older showed inferior outcomes for TRM and overall survival (OS). Mulitivariate analyses confirmed that an age of 50 or over was an independent risk factor for TRM (P<0.0001) and OS (P<0.0001). Among patients aged 50 or older, increasing age remained an adverse factor for OS (P=0.0213). Regimens including total-body irradiation (TBI) correlated with a higher risk of TRM and a lower OS for older patients (P=0.0095 and 0.0303, respectively). These findings indicate that allogeneic c-HSCT should be offered to patients over 50 years only if the increased risk of TRM is acceptable, and that a non-TBI regimen is preferable when the transplant is performed.

Adolescent↗

PubMed2004

Tacrolimus instead of cyclosporine used for prophylaxis against graft-versus-host disease improves outcome after hematopoietic stem cell transplantation from unrelated donors, but not from HLA-identical sibling donors: a nationwide survey conducted in Japan.

Despite recent advances, graft-versus-host disease (GVHD) remains the main cause of treatment failure for patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Tacrolimus (FK506) has been increasingly used in place of cyclosporine (CSP), and several studies have shown that FK506 reduces the incidence of acute GVHD more effectively than does CSP. However, no survival benefits have been demonstrated, and no established consensus exists on the choice of these immunosuppressive agents. To compare a CSP-based and an FK506-based regimen, we performed a large-scale retrospective study by using the data of 1935 patients who underwent HSCT from HLA-identical sibling donors (SIB-HSCT) and 777 patients who underwent HSCT from unrelated donors (UD-HSCT). For patients undergoing UD-HSCT, FK506 significantly reduced the risk of acute GVHD and treatment-related mortality (TRM) without an increase in relapse, thus improving overall survival (OS) (hazard ratio (HR): 2.20, 95% confidence interval (CI): 1.60-3.04, P<0.0001 for grade II-IV acute GVHD; HR: 1.81, 95% CI: 1.32-2.48, P=0.0003 for TRM; HR: 1.62, 95% CI: 1.23-2.14, P=0.0007 for OS). This superiority of FK506 was not observed in SIB-HSCT cases. These findings indicate that the use of FK506 instead of CSP for GVHD prophylaxis is beneficial for patients undergoing UD-HSCT.

Acute Disease↗

PubMed2004

Allelic diversity of S-RNase at the self-incompatibility locus in natural flowering cherry populations (Prunus lannesiana var. speciosa).

In the Rosaceae family, which includes Prunus, gametophytic self-incompatibility (GSI) is controlled by a single multiallelic locus (S-locus), and the S-locus product expressed in the pistils is a glycoprotein with ribonuclease activity (S-RNase). Two populations of flowering cherry (Prunus lannesiana var. speciosa), located on Hachijo Island in Japan's Izu Islands, were sampled, and S-allele diversity was surveyed based on the sequence polymorphism of S-RNase. A total of seven S-alleles were cloned and sequenced. The S-RNases of flowering cherry showed high homology to those of Prunus cultivars (P. avium and P. dulcis). In the phylogenetic tree, the S-RNases of flowering cherry and other Prunus cultivars formed a distinct group, but they did not form species-specific subgroups. The nucleotide substitution pattern in S-RNases of flowering cherry showed no excess of nonsynonymous substitutions relative to synonymous substitutions. However, the S-RNases of flowering cherry had a higher Ka/Ks ratio than those of other Prunus cultivars, and a subtle heterogeneity in the nucleotide substitution rates was observed among the Prunus species. The S-genotype of each individual was determined by Southern blotting of restriction enzyme-digested genomic DNA, using cDNA for S-RNase as a probe. A total of 22 S-alleles were identified. All individuals examined were heterozygous, as expected under GSI. The allele frequencies were, contrary to the expectation under GSI, significantly unequal. The two populations studied showed a high degree of overlap, with 18 shared alleles. However, the allele frequencies differed considerably between the two populations.

Alleles↗

PubMed2004

Memantine, an NMDA antagonist, prevents the development of hyperthermia in an animal model for serotonin syndrome.

BACKGROUND: Serotonin (5-HT) syndrome is the most serious side effect of antidepressants. Although several drugs have been used for the treatment of 5-HT syndrome, a universal pharmacotherapy has not been established. NMDA receptor antagonists have been reported to have neuroprotective effects. In the present study, the efficacy of NMDA antagonists, including memantine and MK-801, and potent 5-HT (2A) antagonists, including risperidone and ketanserin, was evaluated in a 5-HT syndrome animal model. METHODS: 5-Hydroxy-l-tryptophan (100 mg/kg) and clorgyline (2 mg/kg) were administered intraperitoneally in rats to induce 5-HT syndrome. The rectal temperature of the rats was measured, and the noradrenaline (NA) and 5-HT levels in the anterior hypothalamus were measured using a microdialysis technique. RESULTS: In the group pretreated with saline, the rectal temperature increased to more than 40 degrees C, and all of the animals died within 90 min of the drug's administration. The NA and 5-HT levels in the anterior hypothalamus increased to about 15- and 1100-fold of the pre-administration levels, respectively. Pretreatment with risperidone (0.5 mg/kg) and ketanserin (5 mg/kg) prevented the development of hyperthermia and the increase in the NA level. Memantine (10 mg/kg) and MK-801 (0.5 mg/kg) also prevented the development of hyperthermia and the increase in the NA level. These results suggest that NMDA antagonists, as well as potent 5-HT (2A) antagonists, may be effective drugs for the treatment of 5-HT syndrome. CONCLUSIONS: Since memantine is clinically well tolerated, this drug is a particularly promising therapeutic drug for 5-HT syndrome treatment.

5-Hydroxytryptophan↗

PubMed2004

Chromoendoscopy using indigo carmine dye spraying with magnifying observation is the most reliable method for differential diagnosis between non-neoplastic and neoplastic colorectal lesions: a prospective study.

BACKGROUND AND AIMS: Differential diagnosis between non-neoplastic and neoplastic lesions is very important at colonoscopy, since removal or biopsy of non-neoplastic polyps wastes time and resources. We therefore conducted a prospective study to examine whether indigo carmine dye spraying with and without magnification is more reliable than the conventional method for differential diagnosis. PATIENTS AND METHODS: 122 patients with 206 lesions of 10 mm or smaller were recruited into this study. All lesions detected on colonoscopy were first diagnosed using the conventional view, then at chromoendoscopy using 0.2 % indigo carmine, and finally at chromoendoscopy with magnification. The diagnosis at each step were recorded consecutively. All lesions were finally categorized as neoplastic or non-neoplastic according to pit pattern; non-neoplastic lesions were biopsied for histological evaluation, and all the neoplastic ones were removed endoscopically. The accuracy rate of each type of endoscopic diagnosis was evaluated, using histological findings as reference. RESULTS: Histologically, 46 lesions (22 %) were non-neoplastic and 160 (78 %) were neoplastic. The overall diagnostic accuracies by conventional view, chromoendoscopy, and chromoendoscopy with magnification were 84.0 % (173/206), 89.3 % (184/206) and 95.6 % (197/206), respectively. CONCLUSION: Chromoendoscopy with magnification is the most reliable method for determining whether a colorectal lesion is non-neoplastic or neoplastic.

Adult↗

PubMed2004

Primary omental gamma/delta T-cell lymphoma involving the central nervous system.

Gamma/delta T-cell lymphoma (GDTL) is an uncommon lymphoma that was initially reported to involve only the liver and spleen. GDTL other than the hepatosplenic type is extremely rare. Frequent primary sites include skin and subcutaneous tissue, intestine, or nasal region. We report a case of GDTL of the omentum in a 54 year-old-man. The tumor cells are CD2-, CD3+, CD4-, CD5-, CD8+, CD56+, TIA-1+, granzyme B+/-. They expressed the identical phenotype of intestinal GDTL. The patient was treated with 2 courses of CHOP which comprised cyclophosphamide, doxorubicin, vincristine and prednisolone, and 3 courses of EPOCH which comprised etoposide, prednisolone, vincristine, cyclophosphamide and doxorubicin. However, he failed to obtain remission. During the fourth course of EPOCH, muscle weakness of the lower extremities developed and intracranial masses were observed by computed tomographic scan of the brain. Dissemination of lymphoma to the central nervous system was considered and it may be attributable to the expression of CD56 in this case. High dose methotrexate (HD-MTX) chemotherapy successfully eliminated the omental tumor and reduced the size of the intracranial masses, thus HD-MTX appears to be an effective treatment against GDTL.

Central Nervous System↗

PubMed2004

Quantitative detection of periodontal pathogens using real-time polymerase chain reaction with TaqMan probes.

Quantitative analysis, with identification of periodontopathic bacteria, is important for the diagnosis, therapeutic evaluation and risk assessment of periodontal disease. We developed a highly sensitive and specific method using real-time polymerase chain reaction (PCR) to detect and quantify six periodontal bacteria: Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans, Treponema denticola, Prevotella intermedia, and Prevotella nigrescens. Species-specific TaqMan probe/primer sets were designed according to 16S ribosomal RNA gene sequences. Plaque and tongue debris specimens were collected from 10 patients with advanced periodontitis and 10 periodontal healthy individuals and analyzed. All species, except for P. nigrescens, were detected in samples from diseased sites in significantly greater numbers than in those from healthy sites, whereas greater numbers of P. nigrescens were found in the controls. These results suggest that the present real-time PCR method with the designed probe/primer sets enabled sensitive detection of the six periodontal bacteria, and may also assist future microbial studies of periodontal diseases.

Aggregatibacter actinomycetemcomitans↗

PubMed2004

Diversity of vacA and cagA genes of Helicobacter pylori in Japanese children.

BACKGROUND: Helicobacter pylori infection is generally acquired in childhood and persists as an asymptomatic infection for decades in most infected individuals. Only a minority develops a clinical outcome even in childhood, such as peptic ulcer. It has been reported that H. pylori infection with the type I strain, which expresses the VacA and CagA antigen, is associated with peptic ulcer. AIM: We examined the diversity of vacA and cagA genes in isolates obtained from Japanese paediatric patients with peptic ulcer or chronic gastritis to investigate the relationship between genetic diversity and clinical outcome. METHODS: The diversity of vacA and cagA genes was investigated by PCR and sequence analysis in 30 isolates obtained from Japanese paediatric patients with peptic ulcer (eight strains) or chronic gastritis (22 strains). RESULTS: All isolates from Japanese children were cagA-positive strains. Twenty-six strains (86.7%) had East Asian type CagA, and 4 (13.3%) had Western type CagA. The predominant vacA genotype was s1c/m1b (22/30, 73.3%). There was no significant association between the diversity of cagA and vacA genes and clinical outcome. All four children infected with Western CagA strain had a history of overseas travel or residence. CONCLUSION: The predominant genotype of H. pylori in Japanese children is East Asian CagA and vacA s1c/m1b genotype, regardless of clinical outcome. Japanese H. pylori strains are homogeneously of the East Asian type; however, Western strains can be introduced into Japan concomitant with host movement from foreign countries in childhood.

Antigens, Bacterial↗

PubMed2004

Sex differences in mucosal response to Helicobacter pylori infection in the stomach and variations in interleukin-8, COX-2 and trefoil factor family 1 gene expression.

BACKGROUND: Gastric cancer incidence in men is almost double that in women. We investigated mucosal responses in the stomach against Helicobacter pylori (H. pylori) infections to elucidate the interindividual or sex-related differences, which may in turn be associated with gastric cancer incidence, mucosal changes of stomach as measured by the Sydney System, and interleukin-8, cyclooxygenase-2 and trefoil factor family 1 (TFF1) gene expression. METHODS: An age-, sex-, H. pylori status- and disease-matched case-control study was performed in 574 H. pylori-positive and 225 H. pylori-negative patients selected from 4125 patients with a diagnosis of benign disease of the stomach. Levels of acute and chronic inflammations, atrophy and intestinal metaplasia scored according to the Sydney System were compared by stomach site and by sex. Two biopsy specimens (antral and corpus gastric mucosa) from patients with benign gastric diseases (142 patients; 72 men, 70 women) were analysed for interleukin-8, cyclooxygenase-2 and TFF1 mRNA expression as measured by real-time PCR. RESULTS: Inflammation and activity scores in antrum with H. pylori infection were higher in men, but scores declined according to age. Atrophy and intestinal metaplasia scores in corpus with H. pylori infection appeared more severe in men than in women, especially in older patients. In women, atrophy score increased with increasing age, particularly in postmenopausal H. pylori-negative patients. Interleukin-8 mRNA induction was detected in both antrum and corpus mucosa in H. pylori infection, but sex differences were not found. Response of cyclooxygenase-2 mRNA expression against H. pylori infection in the mucosa was higher in men than women. In H. pylori-negative patients, TFF1 mRNA levels in women were significantly higher than in men, and TFF1 mRNA was significantly lower in positive than negative women. CONCLUSIONS: Sex differences in mucosal responses to H. pylori infection in the stomach may be correlated with sex differences in the incidence of stomach cancer.

Aged↗

PubMed2004

Diagnostic value of culture, histology and PCR for Helicobacter pylori in the remnant stomach after surgery.

BACKGROUND: Diagnosis of Helicobacter pylori infection in the remnant stomach has not been established. AIMS: To investigate the diagnostic value of culture, histology, PCR and serum IgG against H. pylori (ELISA) with and without eradication therapy in the remnant stomach, compared with the unoperated stomach. METHODS: Biopsy samples for bacterial culture and histological diagnosis of H. pylori were taken from the stoma and upper corpus of the remnant stomach and gastric juice was used for PCR assay. RESULTS: Bacterial culture-based diagnosis in the remnant stomach, sensitivity and specificity of culture were 95.1%, 100%; histology 89%, 92.3%; PCR 66%, 89.7%; and ELISA 100%, 50%, respectively, in cases without H. pylori eradication therapy. In assessment of the results of therapy for the remnant stomach, sensitivity and specificity of culture were 100%, 100%; histology 80%, 96.8%; PCR 80%, 91.7%; and ELISA 100%, 0%, respectively. CONCLUSION: Bacterial culture had the highest diagnostic value in the remnant stomach as well as unoperated stomach. Sensitivity by histology and PCR was lower in the remnant stomach than the unoperated stomach, but specificity values were equal. Serum ELISA assay was not suitable for the remnant stomach.

Adult↗

PubMed2004

Helicobacter pylori in Japanese river water and its prevalence in Japanese children.

AIMS: The major transmission route of Helicobacter pylori remains unclear. In this study, we examined H. pylori in the environmental waters in Japan. METHODS AND RESULTS: A total of 24 water samples were collected from the upper, middle and downstream reaches of four Japanese rivers. Helicobacter pylori-specific DNA was examined using nested PCR. In addition, 224 children who lived near one river were studied by the stool antigen test for H. pylori prevalence. Helicobacter pylori DNA was detected in the water from the middle and downstream reaches of all four rivers, but not in the upper reaches. Helicobacter pylori was not found in cultured water samples with positive PCR results. Helicobacter pylori prevalence in the children examined was 9.8% for those living near the middle reaches and 23.8% nearby downstream, both of which were higher than the value in an area distant from the river (0%) (both, P < 0.01). CONCLUSIONS: Difference in H. pylori prevalence in the children may be related to the presence of H. pylori in the river. The results of this study showed that H. pylori DNA is frequently present in river water from the middle and downstream reaches in which the human biosphere is embedded. SIGNIFICANCE AND IMPACT OF THE STUDY: It is suggested that river water in the natural environment could be a risk factor for H. pylori transmission.

Child↗