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Biomedical subjects

K Shibata

Publications and source records attributed to K Shibata.

At least 37 records · Page 2Linked to original sources
PubMed2004

Salmonella Enteritidis outbreak associated with a school-lunch dessert: cross-contamination and a long incubation period, Japan, 2001.

A Salmonella Enteritidis (SE) outbreak in Japan was investigated with an observational study, analytical epidemiology and bacteriological examination (including phage typing). The outbreak occurred among 96 schoolchildren, and was caused by SE phage type 1. The outbreak source was dessert buns served at a school lunch (RR 42.55, 95 % CI 5.93-305.11, P < 0.001). The buns were probably cross-contaminated from eggs from a factory with a history of SE-contaminated products. The incubation period was longer than usual (3-16 days, median 8 days). A low contaminating dose may account for the long incubation period and low attack rate. Outbreak detection was hampered by the absence of routine Salmonella surveillance in Japan. The investigation was complicated by concurrent illnesses from other SE phage types. It was successful, in part, because adequate food samples were available for microbiological testing.

Child↗
PubMed2004

Effects of neuromuscular-blocking drugs in rats in vivo: direct measurements in the diaphragm and tibialis anterior muscle.

BACKGROUND: Effects of neuromuscular-blocking drugs are often investigated in rodents using both the diaphragm in vitro and the tibialis anterior muscle in vivo. Differences in the properties of these muscles cannot be neglected. We evaluated the neuromuscular effects of drugs on the rat diaphragm in vivo in comparison with the tibialis anterior muscle, directly measuring twitch tension with a force transducer. METHODS: Respectively using sternotomy and an approach via the gluteal space, transducers were attached to the diaphragm and the tibialis anterior muscle. Phrenic and sciatic nerves were stimulated supramaximally by single square pulses to record isometric contraction of muscles. Pancuronium, vecuronium, or rocuronium was infused continuously at a rate adjusted repeatedly until stable tension was obtained. Effective doses for 50% (ED 50) and 90% (ED 90) depression of tension were calculated, using a cumulative infusion dosing method. RESULTS: Isometric contraction of the diaphragm could be recorded despite movements of the heart and lungs. For all three drugs, both mean ED 50 and ED 90 were more than twice as large for the diaphragm as for the tibialis anterior (P<0.05). In addition, slopes of dose-response curves for the diaphragm were significantly less steep than those of the tibialis anterior for the three drugs. CONCLUSION: Neuromuscular-blocking effects on the diaphragm can be recorded in vivo. According to direct contractile force measurement, the diaphragm is more resistant to non-depolarizing neuromuscular-blocking drugs than the tibialis anterior muscle.

Animals↗
PubMed2004

[Novel strategy for spinal cord protection during thoracoabdominal aortic aneurysm surgery using Doppler ultrasonography].

Paraplegia remains one of the most serious complications after thoracoabdominal aortic aneurysm surgery. Spinal cord ischemia during the operation is thought to be the most important contributor to the development of this neurological deficit. So, it is important to preserve or reconstruct the critical segmental arteries for spinal cord protection. In order to identify the critical segmental arteries, we evaluate the segmental arteries by measuring the flow velocities using Doppler ultrasonography. The flow velocities are different among segmental arteries and some segmental arteries have no flow even though they are patent. Because we think that the segmental arteries with high flow velocities have much contribution to the spinal cord perfusion, we reconstruct or preserve such segmental arteries during the operation. We hope that this method would be clinically useful for spinal cord protection during thoracoabdominal aortic aneurysm surgery.

Aortic Aneurysm, Abdominal↗
PubMed2004

[Postoperative pulmonary and cardiovascular complication of patients aged over 70-year with lung tumor].

The complication of surgery for lung tumor was reviewed in 43 patients aged over 70-year. 6 of 43 patients had postoperative pulmonary and cardiovascular complication. We assessed age, sex, surgical procedure, underlying disease, %vital capacity, forced expiratory volume in 1 second %, PO2, electrocardiogram and %heart rate (heart rate on electrocardiogram at rest/maximal predicted heart rate) for predictal value of postoperative pulmonary and cardiovascular complication.

Aged↗
PubMed2003

Gemcitabine and vinorelbine followed by docetaxel in patients with advanced non-small-cell lung cancer: a multi-institutional phase II trial of nonplatinum sequential triplet combination chemotherapy (JMTO LC00-02).

To evaluate the efficacy and toxicity of the sequential nonplatinum combination chemotherapy consisting of gemcitabine (GEM) and vinorelbine (VNR) followed by docetaxel (DOC) in patients with advanced non-small-cell lung cancer (NSCLC), we conducted the multiinstitutional phase II study. A total of 44 chemotherapy-naive patients with advanced NSCLC were treated with GEM 1000 mg m(-2) and VNR 25 mg m(-2) intravenously on days 1 and 8 every 3 weeks for three cycles. DOC 60 mg m(-2) was then administrated intravenously at 3-week intervals for three cycles. Patients were evaluated for response and toxicity with each cycle of the treatment. The major objective response rate was 47.7% (95% confidence interval (CI), 33.8-62.1%). Median survival time (MST) was 15.7 months and 1-year survival rate was 59%. In the GEM/VNR cycle, grade 3/4 neutropenia occurred in 36.3%, grade 3/4 anaemia in two patients (4.5%) and grade 3 thrombocytopenia in one patient (2.3%). Grade 3 pneumonitis occurred in two patients (4.5%) in GEM/VNR cycles. In the DOC cycles, grade 3/4 neutropenia occurred in 39.4% but no patient experienced grade 3/4 anaemia or thrombocytopenia. Of the 44 eligible patients, 33 patients completed three cycles of GEM/VNR and 22 patients completed six cycles of planned chemotherapy (three cycles of GEM/VNR followed by three cycles of DOC). The sequential triplet nonplatinum chemotherapy consisted of GEM/VNR followed by DOC, and was very active and well tolerated. This study forms the basis for an ongoing phase III trial that compares this nonplatinum triplet and standard platinum doublet combination (carboplatin/paclitaxel).

Adult↗
PubMed2003

Expression of Dmrt1 protein in developing and in sex-reversed gonads of amphibians.

Many genes are known to be involved in gonadal differentiation in vertebrates. Dmrt1, a gene that encodes a transcription factor with a DM-domain, is considered to be one of the essential genes controlling testicular differentiation in mammals, birds, reptiles, amphibians and fish. However, it still remains unknown which testicular cells of animals other than mice and chicks express Dmrt1 protein. For an explanation of its role(s) in testicular differentiation in vertebrates, the expression of the Dmrt1 protein needs to be studied. For this purpose, we conducted an immunohistochemical study of this protein in an amphibian by using an antibody specific for Dmrt1. No positive signal was found in the indifferent gonad of tadpoles of Rana rugosa at early stages. However, in the testis of tadpoles at later stages (XV-XXV) and in frogs one month after metamorphosis, this protein was expressed in interstitial cells and Sertoli cells. In the testis of adult frogs, germ cells also expressed Dmrt1 protein. RT-PCR analysis revealed that the gene for this protein was not transcribed at any time during ovarian development, but was expressed in the female to male sex-reversed gonad. This was true when immunohistological studies were performed. In addition, Southern blot analysis showed DMRT1 to be an autosomal gene. Taken together, our findings indicate that Dmrt1 protein is expressed by interstitial cells, Seroli cells and germ cells in the testis of R. rugosa. Dmrt1 may thus be very involved in the testicular differentiation of amphibians.

Animals↗
PubMed2002

Comprehensive sequence analysis of translation termination sites in various eukaryotes.

Recent investigations into the translation termination sites of various organisms have revealed that not only stop codons but also sequences around stop codons have an effect on translation termination. To investigate the relationship between these sequence patterns and translation as well as its termination efficiency, we analysed the correlation between strength of consensus and translation efficiency, as predicted according to Codon Adaptation Index (CAI) value. We used RIKEN full-length mouse cDNA sequences and ten other eukaryotic UniGene datasets from NCBI for the analyses. First, we conducted sequence profile analyses following translation termination sites. We found base G and A at position +1 as a strong consensus for mouse cDNA. A similar consensus was found for other mammals, such as Homo sapiens, Rattus norvegicus and Bos taurus. However, some plants had different consensus sequences. We then analysed the correlation between the strength of consensus at each position and the codon biases of whole coding regions, using information content and CAI value. The results showed that in mouse cDNA, CAI value had a positive correlation with information content at positions +1. We also found that, for positions with strong consensus, the strength of the consensus is likely to have a positive correlation with CAI value in some other eukaryotes. Along with these observations, biological insights into the relationship between gene expression level, codon biases and consensus sequence around stop codons will be discussed.

3' Untranslated Regions↗
PubMed2002

Neutral endopeptidase/CD10 expression during phorbol ester-induced differentiation of choriocarcinoma cells through the protein kinase C- and extracellular signal-regulated kinase-dependent signalling pathway.

Neutral endopeptidase 24.11 (NEP) is identical to CD10, which is a differentiation antigen for early B-lymphoid progenitors in the B-cell differentiation pathway. This ectoenzyme is known to have a key role in the control of growth, differentiation, and signal transduction of many cellular systems by regulating bioactive peptides and cytokines. Recently, we demonstrated that NEP/CD10 is upregulated during forskolin-induced choriocarcinoma cell differentiation, suggesting that NEP/CD10 is a trophoblast differentiation marker. The purpose of this study was to clarify the enhancement of NEP/CD10 expression and its signal transduction pathway during phorbol ester (PMA)-induced differentiation of BeWo choriocarcinoma cells. PMA-induced differentiation of BeWo cells was confirmed by morphological change and human chorionic gonadotropin (hCG) secretion, which was completely blocked by a protein kinase C (PKC) inhibitor, Bisindolylmaleimide I (Bis I). On immunoblot analysis, PMA enhanced NEP/CD10 expression in a dose- and time-dependent manner, which was completely abolished by Bis I and a mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor, PD98059. PMA also induced phosphorylation of p44/p42 extracellular signal-regulated kinases (ERK) 1 and 2. These observations indicated that activation of PKC by PMA induced differentiation of BeWo cells, and that PMA activated MAPK/ERK, which resulted in the enhancement of NEP/CD10 expression. Furthermore, immunocytochemical analysis showed that NEP/CD10 expression was detected on the membranes of PMA-treated differentiated BeWo cells. In summary, we demonstrated that NEP/CD10 was enhanced during PMA-induced differentiation of BeWo choriocarcinoma cells through a PKC-dependent MEK/ERK signalling pathway. Our findings also suggest that NEP/CD10 may play a functional role in the process of trophoblast differentiation.

Antigens, Differentiation↗
PubMed2002

cDNA cloning and expression of rat leukotriene C(4) synthase: elevated expression in rat basophilic leukemia-1 cells after treatment with retinoic acid.

Leukotriene C(4) synthase (LTC(4) S) is considered a pivotal enzyme for generation of potent proinflammatory mediators, cysteinyl-leukotrienes (cysLTs). LTC(4) S cDNA was cloned in rat basophilic leukemia-1 (RBL-1) cells, and exhibited 84.8% and 94.5% identity with the reported human and mouse LTC(4) S cDNA sequences, respectively. Homology between the rat LTC(4) S amino acid sequence and the corresponding sequences from the other species was 86.5% and 95.3% with human and mouse sequences, respectively. Rat LTC(4) S thus showed extensive homology with both mouse and human cDNA sequences. The active enzyme as assessed by LTC(4) S activity was expressed in COS-7 cells. While RBL-1 cells after the culture for 48 h in the presence of 0.1 microg/ml all trans -retinoic acid (RA) exhibited 27 times higher LTC(4) S activity than control cells, Northern-blot analysis of RA-treated cells showed upregulation of LTC(4) S mRNA. Polyclonal antibody was raised against the synthesized peptide deduced from the nucleotide sequence. Thus, Western-blot analysis of RBL-1 cells treated with RA and COS-7 cells transfected with pcDNA-LTC(4) S commonly showed a band at approximately 18 kDa in each solubilized enzyme solution, but either control cells did not. This cDNA probe and antibody may be useful for investigating the roles of cysLTs in various experimental models of rats.

Amino Acid Sequence↗
PubMed2002

Augmented binding and activation of latent transforming growth factor-beta by a tryptic fragment of latency associated peptide.

Transforming growth factor-beta (TGF-beta) is secreted in a latent form; thus, activation is critical for the control of TGF-beta action. Latent TGF-beta exists in a complex in which mature TGF-beta is noncovalently linked to latency associated peptide (LAP) and latent TGF-beta binding protein (LTBP) complex. We have shown that latent TGF-beta is efficiently activated in heterotypic cultures of endothelial cells (ECs) and smooth muscle cells (SMCs). Under those conditions, LAP plays an important role in targeting latent TGF-beta to the surface of SMCs, and plasmin and calpain target it to the surface of ECs for activation. Here, we demonstrate in a homotypic culture system that fragments of LAP increase the binding of latent TGF-beta to ECs, resulting in its activation by cell-associated proteolysis. LAP fragments appear to bind to the cell surface and augment the binding of latent TGF-beta, independent of transglutaminase. These results suggest a unique mechanism for the activation of latent TGF-beta by proteolytic fragments of LAP. The mechanism may arise from degradation by elevated levels of proteases under certain conditions.

Amino Acid Sequence↗
PubMed2001

Novel and simple two-step purification of a full-length rat glucocorticoid-receptor expressed in a baculovirus system.

We purified the activated recombinant glucicorticoid receptor (GR) overexpressed in insect cells by sequential chromatographies using Mono Q and Mono S columns. This procedure was based upon a new finding that the activated GR binds both to a Mono Q column and to a Mono S column at the same pH (pH 8.4). The entire chromatographies took about 3 h and GR represented 97% of the purified protein sample. The purified GR was able to bind specifically to a DNA fragment containing the glucocorticoid response element. This purification protocol will be applicable to the purification of native GR, point-mutated recombinant GR and other nuclear receptors.

Animals↗
PubMed2001

Phenotypic changes of adrenomedullin receptor components, RAMP2, and CRLR mRNA expression in cultured rat vascular smooth muscle cells.

Adrenomedullin is known to inhibit cell proliferation in cultured rat vascular smooth muscle cells, through a cAMP-dependent process. The calcitonin receptor-like receptor could function as an adrenomedullin receptor when co-expressed with receptor activity-modifying protein 2. To determine whether vascular adrenomedullin receptor components, the calcitonin receptor-like receptor and the receptor activity-modifying protein 2, phenotypically change during in vitro culture conditions, we examined the expression of adrenomedullin receptor components, adrenomedullin-induced cAMP production, and the inhibition of cell proliferation in culture rat vascular smooth muscle cells during serial passages. The results demonstrated that the receptor activity-modifying protein 2 and calcitonin receptor-like receptor mRNAs increased in a passage-dependent manner in rat vascular smooth muscle cells. Furthermore, the responses of both the elevation of cAMP and the inhibition of cell proliferation became larger in vascular smooth muscle cells with an increasing number of passages. The results suggest that the increase in functional AM receptor during phenotypic change may in part contribute to the development of vascular lesions, such as in atherosclerosis.

Adrenomedullin↗
PubMed2001

Contribution of anaphylatoxin C5a to late airway responses after repeated exposure of antigen to allergic rats.

We attempted to elucidate the contribution of complement to allergic asthma. Rat sensitized to OVA received repeated intratracheal exposures to OVA for up to 3 consecutive days, and pulmonary resistance was then estimated for up to 6 h after the last exposure. Whereas the immediate airway response (IAR) in terms of R(L) tended to decrease in proportion to the number of OVA exposures, late airway response (LAR) became prominent only after three. Although premedication with two kinds of complement inhibitors, soluble complement receptor type 1 (sCR1) or nafamostat mesylate, resulted in inhibition of the IAR after either a single or a double exposure, the LAR was inhibited after the triple. Premedication with a C5a receptor antagonist (C5aRA) before every exposure to OVA also inhibited the LAR after three. Repeated OVA exposure resulted in eosinophil and neutrophil infiltration into the bronchial submucosa which was suppressed by premedication with sCR1 or C5aRA. Up-regulation of C5aR mRNA was shown in lungs after triple OVA exposure, but almost no up-regulation of C3aR. Pretreatment with sCR1 or C5aRA suppressed the up-regulation of C5aR expression as well as cytokine messages in the lungs. The suppression of LAR by pretreatment with sCR1 was reversed by intratracheal instillation of rat C5a desArg the action of which was inhibited by C5aRA. In contrast, rat C3a desArg or cytokine-induced neutrophil chemoattractant-1 induced cellular infiltration into the bronchial submucosa by costimulation with OVA, but these had no influence on the LAR. These differences might be explained by the fact that costimulation with OVA and C5a synergistically potentiated IAR, whereas that with OVA and either C3a or cytokine-induced neutrophil chemoattractant-1 did not. C5a generated by Ag-Ab complexes helps in the production of cytokines and contributes to the LAR after repeated exposure to Ag.

Airway Resistance↗
PubMed2001

Correlation between sequence conservation of the 5' untranslated region and codon usage bias in Mus musculus genes.

The codon adaptation index (CAI) values of all protein-coding sequences of the full-length cDNA libraries of Mus musculus were computed based on the RIKEN mouse full-length cDNA library. We have also computed the extent of consensus in flanking sequences of the initiator ATG codon based on the 'relative entropy' values of respective nucleotide positions (from -20 to +12 bp relative to the initiator ATG codon) for each group of genes classified by CAI values. With regard to the two nucleotides positions (-3 and +4) known to be highly conserved in Kozak's consensus sequence, a clear correlation between CAI values and relative entropy values was observed at position -3 but this was not significant at position +4, although a significant correlation was found at position -1 of the consensus sequence. Further, although no correlation was observed at any additional positions, relative entropy values were very high at positions -4, -6, and -8 in genes with high CAI values. These findings suggest that the extent of conservation in the flanking sequence of the initiator ATG codon including Kozak's consensus sequence was an important factor in modulation of the translation efficiency as well as synonymous codon usage bias particularly in highly expressed genes.

5' Untranslated Regions↗
PubMed2001

Nickel-catalyzed intramolecular homoallylation of omega-dienyl aldehyde.

[reaction: see text] In the presence of a catalytic amount of Ni(acac)(2), Et(3)B and Et(2)Zn nicely promote a reductive homoallylic cyclization of omega-dienyl aldehydes and provide 2-allylcyclopentanols and -cyclohexanols with high stereoselectivity in excellent yield. The reaction requires only two kinds of commercially available, inexpensive reagents, Ni(acac)(2) and Et(2)Zn or Et(3)B, and completes at room temperature within 30 min with Et(2)Zn and 1-2 days with Et(3)B. No ligand additives (e.g., phosphine, nitrogen compounds) are required.

Journal Article↗
PubMed2001

Microchimeric cells from the peripheral blood associated with cardiac grafts are bone marrow derived, long-lived and maintain acquired tolerance to minor histocompatibility antigen H-Y.

BACKGROUND: Although it has been well established that the microchimerism occurs in the peripheral blood of the recipients after various settings in both clinical and experimental organ transplantation, nevertheless, their roles in inducing and maintaining acquired transplantation tolerance are controversial. Furthermore, regarding the cell lineages, kinetics, and functions of the cells that constitute the microchimerism after organ transplantation, solid information is not available. METHODS: Using rat heterotopic heart isografts from bone marrow chimeras between cross-sex and applying polymerase chain reaction with specific primers to rat sex determining region of Y chromosome, a relationship between a state of microchimerism and induction as well as maintenance of acquired tolerance to H-Y antigen were examined. RESULTS: Microchimeric cells of the peripheral blood (MCPB) after cardiac grafting contain bone marrow-derived and radiation-sensitive cells. Furthermore, removal of the primary cardiac grafts revealed that microchimeric cells in the peripheral blood are long-lived cells, i.e., more than 6 months. When the female rats that had contained long-lasting MCPB, were innoculated with syngeneic male dendritic cells, failure to sensitize female toward male specific antigen H-Y was found to occur. CONCLUSIONS: Thus it was suggested that radiation-sensitive, bone marrow derived, long-lived MCPB play a significant role in maintaining acquired transplantation tolerance to minor histocompatibility antigen H-Y.

Animals↗