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Biomedical subjects

Toshiyuki Saito

Publications and source records attributed to Toshiyuki Saito.

11 recordsLinked to original sources
PubMed2003

A sensitive transcriptome analysis method that can detect unknown transcripts.

We have developed an AFLP-based gene expression profiling method called 'high coverage expression profiling' (HiCEP) analysis. By making improvements to the selective PCR technique we have reduced the rate of false positive peaks to approximately 4% and consequently the number of peaks, including overlapping peaks, has been markedly decreased. As a result we can determine the relationship between peaks and original transcripts unequivocally. This will make it practical to prepare a database of all peaks, allowing gene assignment without having to isolate individual peaks. This precise selection also enables us to easily clone peaks of interest and predict the corresponding gene for each peak in some species. The procedure is highly reproducible and sensitive enough to detect even a 1.2-fold difference in gene expression. Most importantly, the low false positive rate enables us to analyze gene expression with wide coverage by means of four instead of six nucleotide recognition site restriction enzymes for fingerprinting mRNAs. Therefore, the method detects 70-80% of all transcripts, including non-coding transcripts, unknown and known genes. Moreover, the method requires no sequence information and so is applicable even to eukaryotes for which there is no genome information available.

Animals↗
PubMed2002

Pathways of anesthetic from the thoracic paravertebral region to the celiac ganglion.

Communication between the lower thoracic paravertebral region and the celiac ganglion through the retrocrural space was investigated. After dye was injected into the endothoracic fascia in the lower thoracic paravertebral region at the T11 level, its spread to the celiac ganglion was examined in fifteen cadavers. The dye reached the celiac ganglion in nine cadavers (60%) by passing through the retrocrural space, along the greater and lesser splanchnic nerves and through the split in the crus of the diaphragm through which the splanchnic nerves traveled. In the remaining six cadavers, dye spread toward the ganglion along the crus of the diaphragm. In three living subjects the spread of a radio-opaque dye injected in the same manner was studied using 3D-computed tomography. This study confirmed that the radio-opaque dye traveled toward the celiac ganglion along the crus of the diaphragm. From our results we suggest that a fluid communication may exist between the lower thoracic paravertebral region and the celiac ganglion in cadavers and in living humans and that clinicians should be aware of this possible route of spread when administering lower thoracic paravertebral anesthesia.

Adult↗
PubMed2002

Cloning of hamster type XVII collagen cDNA, and pathogenesis of anti-type XVII collagen antibody and complement in hamster bullous pemphigoid.

Bullous pemphigoid is an inflammatory subepidermal blistering skin disease associated with an IgG autoimmune response to the type XVII collagen. The immunopathologic features of bullous pemphigoid can be reproduced in mice by the passive transfer of anti-type XVII collagen antibodies. In this model, it is thought that blister formation depends upon complement activation, neutrophil recruitment, and some proteolytic enzymes. In this study, we cloned hamster type XVII collagen cDNA, which contains a 4296 bp coding region and which is predicted to be a transmembrane protein with an extracellular collagenous domain, residing in type II orientation. Antipeptide antibodies (anti-1191 IgG) were obtained against a segment of hamster type XVII collagen homologous with the human type XVII collagen autoantibody-reactive site. The antipeptide antibodies were passively transferred to neonatal Syrian hamsters. The injected hamsters developed a microscopic subepidermal blister as seen previously in the mice. In order to test whether antigen-antibody complexes and complement initiate the subepidermal blister formation, we carried out experiments in vitro on condition that inflammatory cells were completely eliminated. Complement activation in sera was inhibited either by heating (at 56 degrees C for 30 min) or by preincubating with cobra venom factor. When the hamster skin was incubated with fresh anti-1191 antisera, separation of dermal-epidermal junction was observed. The anti-1191 IgG failed to induce C3 deposition and dermal-epidermal junction separation, however, if the anti-1191 IgG was added alone or complement activation in sera was inhibited. Under these conditions, IgG but not C3 was deposited on the basement membrane. These results strongly suggest that antigen-antibody complexes and complement initiate dermal-epidermal junction separation.

Amino Acid Sequence↗
PubMed2002

Appendectomy in rabbits with extended unilateral anesthesia.

Thoracic paravertebral anesthesia was not believed to accompany numbness in the lumbar nerve region. However, we recently discovered that thoracic paravertebral anesthesia could produce analgesia in the lumbar region. We called this block extended unilateral anesthesia. In this study, appendectomy was attempted in rabbits with extended unilateral anesthesia. After a catheter was inserted into the endothoracic fascia in the paravertebral region on the right side at the level of the 11th thoracic vertebra, a 3-ml dose of 2% mepivacaine was injected repeatedly through the catheter. After an injection of the local anesthetic we could observe motor and sensory paralysis unilaterally from the chest down to the lower limb in all the rabbits, the extended unilateral anesthesia. With this anesthesia, we could accomplish appendectomy. This is the initial report of extended unilateral anesthesia applied to appendectomy in rabbits. We think that this anesthesia could be beneficial in future medical and veterinary use.

Analgesia↗
PubMed2002

Sequence analysis of 193.4 and 83.9 kbp of mouse and chicken genomic DNAs containing the entire Prkdc (DNA-PKcs) gene.

The catalytic subunit of DNA-dependent protein kinase plays critical roles in nonhomologous end joining in repair of DNA double-strand breaks and V(D)J recombination. In addition to the SCID phenotype, it has been suggested that the molecule contributes to the polymorphic variations in radiosensitivity and susceptibility to cancer in mouse strains. Here we show the nucleotide sequence of approximately 193-kbp and 84-kbp genomic regions encoding the entire Prkdc gene (also known as DNA-PKcs) in the mouse and chicken, respectively. A large retroposon was found in intron 51 in the mouse but not in the human or chicken. Comparative analyses of the genome strongly suggested that the region contains only two genes for Prkdc and Mcm4; however, several conserved sequences and cis elements were also predicted.

Animals↗
PubMed2002

CJ-21,164, a new D-glucose-6-phosphate phosphohydrolase inhibitor produced by a fungus Chloridium sp.

A new D-glucose-6-phosphate phosphohydrolase (G6Pase) inhibitor, CJ-21,164 (1) was isolated from the fermentation broth of the fungus Chloridium sp. CL48903. The structure was elucidated to be a novel tetramer of the salicylic acid derivatives by spectroscopic analyses. Compound I inhibited G6Pase in rat liver microsomes with an IC50 of 1.6 microM. Glucose output from hepatocytes isolated from rat liver was inhibited when I was present in the incubation medium, consistent with the role of I as a G6Pase inhibitor.

Animals↗
PubMed2002

CJ-21,058, a new SecA inhibitor isolated from a fungus.

A new equisetin derivative, CJ-21,058 (I) was isolated from the fermentation broth of an unidentified fungus CL47745. It shows antibacterial activity against Gram-positive multi-drug resistant bacteria by inhibiting ATP-dependent translocation of precursor proteins across a bacterial cell membrane.

Anti-Bacterial Agents↗
PubMed2002

CJ-15,208, a novel kappa opioid receptor antagonist from a fungus, Ctenomyces serratus ATCC15502.

A novel kappa opioid receptor binding inhibitor CJ-15,208 (I) was isolated from the fermentation broth of a fungus, Ctenomyces serratus ATCC15502. The structure of I was determined to be a cyclic tetrapeptide consisting of one tryptophan, one D-proline, and two L-phenylalanine. Compound I was a selective binding inhibitor for the kappa opioid receptor: 47 nM (IC50) for kappa, 260 nM for mu, and 2,600 nM for delta. In the electrically-stimulated twitch response assay of rabbit vas deferens I recovered the suppression by a kappa agonist asimadoline with an ED50 of 1.3 microM, indicating that it is a kappa antagonist.

Animals↗
PubMed2002

Thielavins as glucose-6-phosphatase (G6Pase) inhibitors: producing strain, fermentation, isolation, structural elucidation and biological activities.

High-throughput screening of microbial extracts using rat hepatic microsomal glucose-6-phosphatase (G6Pase) led us to find thielavin B as a G6Pase inhibitor with inhibition of glucose output from glucagon-stimulated hepatocytes. Further searching for more potent analogs identified 11 new thielavins F-P in addition to the known thielavins A and B from a fungus Chaetomium carinthiacum ATCC 46463. Thielavin G showed the strongest activity as a G6Pase inhibitor (IC50=0.33 microM), while the IC50 of thielavin B was 5.5 microM. According to the structure-activity relationship, including authentic thielavins C, D and 3 partial hydrolysates from thielavins A and B, 3 benzoic acid-units and carboxylic acid functions are essential for G6Pase inhibition.

Animals↗