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Biomedical subjects

T Shimada

Publications and source records attributed to T Shimada.

At least 37 records · Page 2Linked to original sources

Prevalence, serotype distribution, antibiotic susceptibility and genetic profiles of mesophilic Aeromonas species isolated from hospitalized diarrhoeal cases in Kolkata, India.

A comprehensive study was performed to examine incidence, species distribution, drugs sensitivity, virulence genes and molecular fingerprints of Aeromonas species isolated from patients with acute diarrhoea over a period of 2 years in Kolkata, India. Following the Aerokey II scheme, more than 95 % of strains were identified to species level. Seven different species were encountered in this study, with Aeromonas caviae being dominant, followed by Aeromonas hydrophila and Aeromonas veronii biovar sobria. Thirty different serotypes were encountered, with O16, O83 and O85 being dominant, but no serotype was associated specifically with a single species. The majority of Aeromonas strains exhibited multidrug resistance. The alt and act genes, which encode heat-labile cytotonic and cytotoxic enterotoxins, were respectively found in 71.9 and 20.1 % of strains examined. Only 2.4 % of strains carried the heat-stable cytotonic enterotoxin (ast) gene. The hlyA gene was found in 28 % of Aeromonas strains. With few exceptions, genomic diversity of Aeromonas strains belonging to the same serotype was observed by random amplification of polymorphic DNA PCR and ribotyping. Different species of Aeromonas and different clones of Aeromonas species seem to be associated with hospitalized cases of diarrhoea in Kolkata, India.

Aeromonas↗

Near-triploidy and near-tetraploidy in hematological malignancies and mutation of the p53 gene.

Hyperdiploidy of > or =58 chromosomes is reported in 0.5-3% of hematological malignancies, but reports of near-triploidy (58-80 chromosomes) and near-tetraploidy (81-103 chromosomes), are few. We examined these chromosome abnormalities and analyzed the relationship with the mutation of the p53 gene. Thirty-one of 979 adult patients (3.2%) with hematological malignancies were identified as having near-triploid or near-tetraploid (tri-/tetraploid) chromosomes. These included 11 with B-cell neoplasms, seven with Hodgkin's lymphoma, five with T-cell neoplasms, four with myelodysplastic syndromes and four with acute myeloid leukemias. All patients had concurrent complex chromosome aberrations. Deletion of one allele of the p53 gene was found in two patients and a point mutation of the p53 gene was detected in five patients. Although abnormalities of the p53 gene have been reported in about 10% of hematological malignancies, these were found in seven of 31 (23%) patients with tri-/tetraploidy. These findings suggest that the abnormality of the p53 gene may be closely related with tri-/tetraploidy. The four myelodysplastic syndrome (MDS) patients with tri-/tetraploidy had a significantly worse prognosis than those with diploid cytogenetics (n = 35; P < 0.002). In B-cell neoplasms (n = 3), triploidy was associated with a worse prognosis than tetraploidy (n = 8) and diploidy (n = 130; P < 0.02).

Adult↗

Indometacin up-regulates TFF2 expression in gastric epithelial cells.

BACKGROUND: Trefoil factor family peptides are expressed in gastrointestinal epithelial cells and play a critical role in maintaining mucosal integrity. Although non-steroidal anti-inflammatory drugs (NSAIDs) are important causative agents of gastric mucosal lesions, few data are available about the effect of NSAIDs on trefoil family peptides in gastric mucosa. AIM: To examine whether indometacin, a widely used NSAID, affects trefoil factor family expression in gastric epithelial cells. METHODS: MKN45, a cell line derived from human gastric cancer, was used. TFF1, TFF2, and TFF3 mRNA expression was assessed by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). TFF2 gene transcription was also examined by luciferase reporter gene assay. RESULTS: Relative expression level of TFF1, TFF2, TFF3 mRNA was 616: 12: 1 in unstimulated MKN45 cells. Although indometacin (1-250 micro mol/L) had no significant effect on the expression of TFF1 and TFF3 mRNA, it up-regulated TFF2 mRNA expression in a dose- and time-dependent manner. Luciferase reporter gene assay confirmed the up-regulation of TFF2 gene transcription by indometacin. Indometacin-induced up-regulation of TFF2 expression was not antagonized by externally applied prostaglandin E2. CONCLUSION: These results suggest that indometacin up-regulates gastric epithelial cell TFF2 expression through a COX-independent mechanism. Since TFF peptides play an important role in gastric mucosal protection, indometacin-induced TFF2 may reduce the degree of gastric mucosal damage induced by indometacin.

Anti-Inflammatory Agents, Non-Steroidal↗

Effects of lysed Enterococcus faecalis FK-23 on allergen-induced serum antibody responses and active cutaneous anaphylaxis in mice.

BACKGROUND: Our previous studies have presented evidence that lysed Enterococcus faecalis FK-23 (LFK), a lysozyme and heat-treated probiotic product, can inhibit allergen-induced local accumulation of eosinophils in mice. OBJECTIVE: The purpose of this experimental study was to evaluate the influence of orally administrated LFK on the host immune responses. METHODS: BALB/c mice were sensitized subcutaneously, and challenged intraperitoneally by cedar pollen allergen. Blood and spleen samples were collected after oral administration of LFK 60 mg/day for 21 days. The serum levels of total and allergen-specific IgE and IgG2a antibodies and the production of IL-4, IL-5 and IFN-gamma generated by allergen-stimulated cultured splenocytes were determined. Additionally, the effect of LFK on active cutaneous anaphylaxis (ACA) induced by ovalbumin (OVA) challenge in mice was measured after 28 days LFK treatment. RESULTS: No significant differences in serum immunoglobulin levels, as well as in cytokine production of splenocytes were observed between LFK-treated and control mice (P>0.05). There was, however, an increasing tendency of allergen-specific IgG2a level in mice after LFK treatment for 21 days compared with controls (P=0.060). Furthermore, the serum ratio of specific IgE to IgG2a was found to be significantly decreased in the LFK group (P=0.005). In addition, a significant inhibition of OVA-induced ACA reaction was observed in mice that had been fed for 28 days with LFK compared with control mice (P=0.008). CONCLUSION: These results suggest that LFK shows an anti-inflammatory effect, which may be part of the mechanism for protection against IgE-mediated allergy.

Administration, Oral↗

Geographic and seasonal variations of the number of B chromosomes and external morphology in Psathyropus tenuipes (Arachnida: Opiliones).

Psathyropus tenuipes (= Metagagrella tenuipes) is a harvestman that harbors B chromosomes with extremely high frequency (individuals without Bs are only 1% of the total number of specimens so far examined) and high numbers (mean number of Bs per individual is about 4). Geographic variations of the number of Bs and external morphology of the species and the relationship between them were studied. A northward increase in the number of Bs was detected throughout the Japanese Islands, though the number also varied considerably locally. Latitudinal gradients were also found in some external characters, while there were no correlations between those external morphologies and the number of Bs. Principal component analysis using eight morphological data for 21 populations revealed four geographical groups that reflect actual location of the populations. Populations along the Seto Inland Sea were characterized by a lower number of Bs than those in other areas. Seasonal change was also found in a population (Yatsukami in western Honshu) in both 1994 and 1995 for the number of Bs, though the number in the same population was stable at least throughout later postembryonic stages in both 1997 and 1998. Embryos contained fewer numbers of Bs than adults, suggesting that females of the species tend to lay eggs with fewer numbers of Bs.

Animals↗

Lysed enterococcus faecalis FK-23 oral administration reveals inverse association between tuberculin responses and clinical manifestations in perennial allergic rhinitis: a pilot study.

BACKGROUND: The interest in anti-allergy immunoregulation by lactic acid bacteria (LAB) has been growing over the last few decades. There is evidence to suggest that lysed Enterococcus faecalis FK-23 (LFK), a kind of LAB preparation, could relieve the clinical symptoms of Japanese cedar pollinosis. However, little is known about how LFK plays a role in combating allergy. OBJECTIVE: The aim of this study was to clarify whether improvement of clinical manifestations is associated with enhancement of tuberculin responses in patients with allergic rhinitis treated by LFK. METHODS: One gram of LFK per day was administered orally to fifty perennial allergic rhinitis patients in an open trial that lasted 28 days. Nasal symptoms and sign scores were rated before and after administration of LFK. Tuberculin responses and peripheral blood cells were also measured before and after LFK treatment. RESULTS: Purified protein derivative (PPD) skin test diameter was 2.14 +/- 2.14 mm before LFK administration versus 7.26 +/- 4.81 mm at day 31 (p < 0.01). A significant inverse correlation was recognized between PPD skin test diameters and total nasal scores in the nasal provocation test before and after treatment (r= - 0.600, p < 0.001). Peripheral blood eosinophils were 248 +/- 149 cells/ml before LFK administration and then they significantly decreased to 76 +/- 98 cells/microl (p < 0.01). CONCLUSIONS: These finding may be interpreted as a result of improved clinical symptoms in allergic rhinitis after LFK oral treatment owing to the enhanced host's Th1-type immune responses and supression of the over-expression of Th2-dominated allergic responses.

Administration, Oral↗

The quantity and diversity of infectious viruses in various tissues of SHIV-infected monkeys at the early and AIDS stages.

To detect the major sites of viral replication in immunodeficiency virus-infected individuals, we quantified proviral DNA and infectious viruses using quantitative PCR and a plaque assay, respectively, in various tissues of SHIV(KU-2)-infected monkeys in the early and AIDS stages of infection. Compared the quantity of infectious virus among PBMC and the lymphoid tissues, the mesenteric lymph node had the largest number of infectious viruses at the AIDS stage more than at the early stage of infection. These results suggested that the gastrointestinal tract was a major site of viral replication. In the brain, proviral DNA was detected at the early and AIDS stage of infection, but infectious viruses were detected at only the AIDS stage. Moreover, we analyzed the nucleotide sequences of the env V3 region in infectious virus clones isolated from each plaque. The viruses in the lymphoid tissues of the monkey that developed AIDS diverged from the inoculated virus and had the same three amino acid substitutions. However, the viruses in the brain were almost identical to the inoculated virus, suggesting that the virus entered the brain early after infection and persisted without replication and genetic diversion until the AIDS stage.

Amino Acid Sequence↗

Annotation pattern of ESTs from Spodoptera frugiperda Sf9 cells and analysis of the ribosomal protein genes reveal insect-specific features and unexpectedly low codon usage bias.

MOTIVATION: A whole set of Expressed Sequence Tags (ESTs) from the Sf9 cell line of Spodoptera frugiperda is presented here for the first time. By this way we want to identify both conserved and specific genes of this pest species. We also expect from this analysis to find a class of protein sequences providing a tool to explore genomic features and phylogeny of Lepidoptera. RESULTS: The ESTs display both housekeeping as well as developmentally regulated genes, and a high percentage of sequences with unknown function. Among the identified ORFs, almost all ribosomal proteins (RPs) were found with high EST redundancy and hence sequence accuracy. The codon usage found among RP genes is in average surprisingly much less biased in Lepidoptera than in other organisms. Other Spodoptera genes also displayed a low bias, suggesting a general genome expression feature in this Lepidoptera. We also found that the L35A and L36 RP sequences, respectively, display 40 and 10 amino-acid insertions, both being present only in insects. Sequence analysis suggests that they are probably not subjected to a strong selective pressure and may be good phylogenetic markers for Lepidoptera. Most interestingly, the Lepidoptera sequences of 9 RP genes displayed a specific signature different from the canonical one. We conclude that the RP family allows valuable comparative genomics and phylogeny of Lepidoptera. AVAILABILITY: All EST sequence data are available from the private 'Spodo-Base' upon request.

Abstracting and Indexing↗

Toward rational control of Escherichia coli O157:H7 by a phage cocktail.

Twenty six phages infected with Escherichia coli O157:H7 were screened from various sources. Among them, nine caused visible lysis of E. coli O157:H7 cells in LB liquid medium. However, prolonged incubation of E. coli cells and phage allowed the emergence of phage-resistant cells. The susceptibility of the phage-resistant cells to the nine phages was diverse. A rational procedure for selecting an effective cocktail of phage for controlling bacteria was investigated based on the mechanism of phage-resistant cell conversion. Deletion of OmpC from the E. coli cells facilitated the emergence of cells resistant to SP21 phage. After 8 h of incubation, SP21-resistant cells appeared. By contrast, alteration of the lipopolysaccharide (LPS) profile facilitated cell resistance to SP22 phage, which was observed following a 6-h incubation. When a cocktail of phages SP21 and SP22 was used to infect E. coli O157:H7 cells, 30 h was required for the emergence of cells (R-C) resistant to both phages. The R-C cells carried almost the same outer membrane and LPS components as the wild-type cells. However, the reduced binding ability of both phages to R-C cells suggested disturbance of phage adsorption to the R-C surface. Even though R-C cells resistant to both phages appeared, this work shows that rational selection of phages has the potential to at least delay the emergence of phage resistance.

Adsorption↗

Little evidence of transdifferentiation of bone marrow-derived cells into pancreatic beta cells.

AIMS/HYPOTHESIS: Bone marrow cells contain at least two distinct types of stem cells which are haematopoietic stem cells and mesenchymal stem cells. Both cells have the ability to differentiate into a variety of cell types derived from all three germ layers. Thus, bone marrow stem cells could possibly be used to generate new pancreatic beta cells for the treatment of diabetes. In this study, we investigated the feasibility of bone marrow-derived cells to differentiate into beta cells in pancreas. METHODS: Using green fluorescent protein transgenic mice as donors, the distribution of haematogenous cells in the pancreas was studied after bone marrow transplantation. RESULTS: In the pancreas of green fluorescent protein chimeric mice, green fluorescent protein-positive cells were found in the islets, but none of these cells expressed insulin. Previous data has suggested that tissue injury can recruit haematopoietic stem cells or their progeny to a non-haematopietic cell fate. Therefore, low-dose streptozotocin (30 or 50 mg/kg on five consecutive days) was injected into the mice 5 weeks after bone marrow transplantation, but no green fluorescent protein-positive cells expressing insulin were seen in the islets or around the ducts of the pancreas. CONCLUSIONS/INTERPRETATION: Our data suggests that bone marrow-derived cells are a distinct cell population from islet cells and that transdifferentiation from bone marrow-derived cells to pancreatic beta cells is rarely observed.

Animals↗

Genomic sequence of a 320-kb segment of the Z chromosome of Bombyx mori containing a kettin ortholog.

The sex chromosome constitution of the silkworm, Bombyx mori, is ZW in the female and ZZ in the male. Very little molecular information is available about the Z chromosome in Lepidoptera, although the topic is interesting because of the absence of gene dosage compensation in this chromosome. We constructed a 320-kb BAC contig around the Bmkettin gene on the Z chromosome in Bombyx and determined its nucleotide sequence by the shotgun method. We found 13 novel protein-coding sequences in addition to Bmkettin. All the transposable elements detected in the region were truncated, and no LTR retrotransposons were found, in stark contrast to the situation on the W chromosome. In this 320-kb region, four genes for muscle proteins (Bmkettin, Bmtitin1, Bmtitin2, and Bmprojectin) are clustered, together with another gene (Bmmiple) on the Z chromosome in B. mori; their orthologs are also closely linked on chromosome 3 in Drosophila, suggesting a partial synteny. Real-time RT-PCR experiments demonstrated that transcripts of 13 genes of the 14 Z-linked genes found accumulated in larger amounts in males than in female moths, indicating the absence of gene dosage compensation. The implications of these findings for the evolution and function of the Z chromosome in Lepidoptera are discussed.

Amino Acid Motifs↗

Adsorption of thiolates to singly coordinated sites on Au111 evidenced by photoelectron diffraction.

The adsorption structure of methylthiolate (CH3S) adsorbed on Au(111), a long-standing controversial issue, has been unambiguously determined by scanned-energy and scanned-angle S 2p photoelectron diffraction. The methylthiolate molecules are found to occupy atop sites with a S-Au distance of 2.42 +/- 0.03 A. The angular distribution of the S 2p photoelectrons due to forward scattering reveals that the S-C bond is inclined by approximately 50 degrees from the surface normal towards both the [211] and [121] (nearest-neighbor thiolate) directions.

Journal Article↗

Migration of enhanced green fluorescent protein expressing bone marrow-derived microglia/macrophage into the mouse brain following permanent focal ischemia.

Brain ischemia induces a marked response of resident microglia and hematopoietic cells including monocytes/macrophages. The present study was designed to assess the distribution of microglia/macrophages in cerebral ischemia using bone marrow chimera mice known to express enhanced green fluorescent protein (EGFP). At 24 h after middle cerebral artery occlusion (MCAO), many round-shaped EGFP-positive cells migrated to the ischemic core and peri-infarct area. At 48-72 h after MCAO, irregular round- or oval-shaped EGFP/ionized calcium-binding adapter molecule 1 (Iba 1)-positive cells increased in the transition zone, while many amoeboid-shaped or large-cell-body EGFP/Iba 1-positive cells were increased in number in the innermost area of ischemia. At 7 days after MCAO, many process-bearing ramified shaped EGFP/Iba 1-positive cells were detected in the transition to the peri-infarct area, while phagocytic cells were distributed in the transition to the core area of the infarction. The distribution of these morphologically variable EGFP/Iba 1-positive cells was similar up to 14 days from MCAO. The present study directly showed the migration and distribution of bone marrow-derived monocytes/macrophages and the relationship between resident microglia and infiltrated hematogenous element in ischemic mouse brain. It is important to study the distribution of intrinsic and extrinsic microglia/macrophage in ischemic brain, since such findings may allow the design of appropriate gene-delivery system using exogenous microglia/macrophages to the ischemic brain area.

Animals↗

Adhesion molecule expression by bone marrow CD34-positive cells in aplastic anemia before and after immunosuppressive therapy.

Appropriate adhesion between bone marrow stem cells and the marrow microenvironment is necessary for hematopoiesis, since signals that promote maturation or apoptosis are transmitted from stromal cells to stem cells. In aplastic anemia (AA), interferon-gamma produced by stromal cells has more influence on the pathogenesis of marrow failure than interferon-gamma produced by lymphocytes. We evaluated the expression of cell adhesion molecules, such as very late antigen-4 (CD49d), and -5 (CD49e) or c-kit receptor (CD117), by CD34-positive bone marrow cells in patients with AA who achieved hematological complete remission after immunosuppressive therapy. Before treatment, CD34-positive cells showed markedly higher expression of CD49d and CD49e than cells from healthy controls, indicating the strong adhesion of stem cells to the bone marrow stroma. Expression of CD49d and CD49e was significantly decreased, reaching normal levels, after hematological recovery. These findings suggest that changes in adhesion molecule expression by stem cells are important in the pathology of AA.

Adult↗

Up-regulation of TFF expression by PPARgamma ligands in gastric epithelial cells.

BACKGROUND: Although trefoil factor family peptides (TFF peptides) are assumed to play important roles in gastric mucosal protection, the regulatory mechanism of gastric TFF expression has not been fully understood yet. Recent reports showed gastric expression of peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor known to be involved in the regulation of cell growth and differentiation in other cell types, such as adipocytes. AIM: To determine whether PPARgamma affects the expression of TFF in gastric epithelial cells. METHODS: MKN45 gastric cells were used as a model of gastric epithelial cells. DNA synthesis of the cells was determined by the measurement of BrdU incorporation. The effects of PPARgamma ligands, 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) and troglitazone (TGZ) on TFF expression were assessed by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: MKN45 cells expressed a significant amount of PPARgamma. Both 15d-PGJ2 and TGZ suppressed DNA synthesis of the cells in a dose-dependent manner. In the control condition, MKN45 cells most abundantly expressed TFF1 and the relative expression level of TFF1, TFF2, and TFF3 mRNA was 1700:32:1. TFF1 and TFF2 mRNA levels were significantly up-regulated by the incubation of the cells with 15d-PGJ2 (10 micro m) or TGZ (30 micro m), whereas TFF3 mRNA level was not affected. CONCLUSION: The results of the present study suggest a possible role of PPARgamma in the regulation of TFF expression in gastric epithelial cells.

Blotting, Western↗

Effect of lysed Enterococcus faecalis FK-23 (LFK) on allergen-induced peritoneal accumulation of eosinophils in mice.

BACKGROUND: The interest in anti-allergy immunoregulation by lactic acid bacteria has been growing for the last few decades. There is some evidence to suggest that lysed Enterococcus faecalis FK-23 (LFK) could relieve the clinical symptoms of pollinosis. However, the mechanism responsible for this phenomenon remains unknown. OBJECTIVE: To identify the effect of LFK, a lysozyme treated and heat-killed preparation from the lactic acid bacteria Enterococcus faecalis FK-23 strain, on allergen-induced eosinophil accumulation. METHODS: BALB/c mice were sensitized with ragweed pollen extract, and peritoneal accumulation of eosinophils was induced. A total of 60 mg (0.5 mL) LFK was orally administered to the experimental mouse every day during 21 days of the sensitization period. In addition, LFK 4 mg, 25 mg and 60 mg (each 0.5 mL) were also orally administered to a mouse of each group every day for 21 days. Saline was fed in a dose of 0.5 mL/mouse per day for the same duration as a control. RESULTS: Compared with control mice, LFK-treated mice exhibited decreased ragweed pollen allergen-induced peritoneal accumulation of eosinophils (P = 0.013), which showed a tendency to be in a dose-dependent fashion (P = 0.14). CONCLUSION: The results provide laboratory evidence of the role for LFK, a lactic acid bacteria preparation, in combating eosinophil accumulation.

Administration, Oral↗

Dose-response studies on the induction of liver cytochromes P4501A1 and 1B1 by polycyclic aromatic hydrocarbons in arylhydrocarbon-responsive C57BL/6J mice.

1. To determine the biological effects of 23 polycyclic aromatic hydrocarbons (PAHs) and 3,4,3',4'-tetrachlorobiphenyl, the dose-response studies of the induction of CYP1-dependent xenobiotic oxidation activities by these chemicals in liver microsomes of C57BL/6J mice were studied. 2. In arylhydrocarbon-responsive C57BL/6J mice, the liver microsomal xenobiotic oxidation with substrates of 7-ethoxyresorufin, 7-ethoxycoumarin, (+/-)-benzo[a]pyrene-7,8-diol, dibenzo[a, pyrene-11,12-diol and 2-amino-3,5-dimethylimidazo[4,5-f]quinoline increased by increasing the doses of PAHs to mice, particularly when the PAHs that have been reported to be carcinogenic in experimental animals were used. In arylhydrocarbon receptor-knockout mice, there were no increases in liver microsomal 7-ethoxyresorufin O-deethylation activities nor in liver mRNA levels of CYP1A1, 1A2 and 1B1 by these chemicals. 3. Of the chemicals examined, benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[j]-fluoranthene, 3-methylcholanthrene, dibenz[a,h]anthracene, dibenz[a,c]anthracene and 3,4,3',4'-tetrachlorobiphenyl were potent inducers of the induction of liver microsomal 7-ethoxyresorufin O-deethylation in mice. 4. Other PAHs such as 5-methylchrysene, benzo[a]pyrene, dibenzo[a,l]pyrene, dibenz[a,j]acridine, benzo[a]anthracene and 7,12-dimethylbenz[a]anthracene moderately induced 7-ethoxyresorufin O-deethylation activities in mice. PAHs reported to be weak or less carcinogenic in experimental animals did not induce the xenobiotic oxidation activities of CYP1A1 and 1B1 in the mice. 5. The results suggest that induction of liver microsomal CYP1-dependent xenobiotic oxidation activities is a good tool in determining the potencies of carcinogenic PAHs in arylhydrocarbon-responsive C57BL/6J mice.

Animals↗

Pulmonary adenocarcinoma with osteoblastic bone metastases in a cat.

A 12-year-old male cat with depression and dyspnoea was presented for investigation. Radiography and computed tomography revealed hydrothorax and solid masses involving the sternum, ribs and thoracic vertebrae. The cat died two days after first presentation, and postmortem examination revealed lung masses and proliferative bony lesions. Histologically, a neoplastic proliferation of epithelial cells was seen in the lungs, with a large amount of collagen and deposits of cholesterin. The bone lesions were also composed of neoplastic epithelial cells and abundant calcified osteoid, without atypia. A diagnosis of pulmonary adenocarcinoma with osteoblastic bone metastases was made. This is the first reported case of osteoblastic metastases in the cat.

Adenocarcinoma↗