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Biomedical subjects

H Yamamoto

Publications and source records attributed to H Yamamoto.

At least 253 records · Page 14Linked to original sources
PubMed2001

Characterization and formation mechanism of water-insoluble DNA-matrix induced by UV irradiation.

We have prepared water-insoluble and nuclease resistant DNA-matrixes by UV irradiation. The UV-irradiated DNA-matrix could effectively accumulate and condense harmful DNA-intercalating compounds, such as acridine orange (AO) and ethidium bromide (EB), from diluted aqueous solutions. The binding constant of AO and EB for UV-irradiated DNA were determined to be 1.0 (+/- 0.2) x 10(5) M-1 and 6.8 (+/- 0.3) x 10(4) M-1, respectively; values consisted with reported results for non-irradiated DNA. In addition, the agarose gel electrophoresis and AFM measurements indicate that DNA matrix forms an intermolecular cross-linking structure with the radical reaction. The UV-irradiated DNA-matrixes have potential uses as a biomaterial filter for the removal of harmful DNA intercalating compounds.

Acridine Orange↗
PubMed2001

Decreases of metallothionein and aminopeptidase N in renal cancer tissues.

Good molecular markers for investigating the biochemical differences between renal cancer and surrounding tissues have not yet been developed. Sixteen kidney samples (clear cell RCC) were investigated to determine the differences in the protein components between renal cancer and surrounding tissues, using HPLC analysis. The metallothionein (MT) and zinc levels were consistently lower in renal cancer tissues compared with in surrounding tissues. The mean concentration of MT in normal tissues surrounding renal tumors was about 15 times higher than that in cancer tissues. An immunohistochemical study confirmed that the expression of MT in renal cancer tissues was lower than that in adjacent normal tissues. The activities of aminopeptidases (APs) were significantly decreased in renal cancer tissues compared with in adjacent normal tissues. An immunohistochemical study and Western blot analysis confirmed that the expression of AP-N in renal cancer tissues was also lower than in adjacent normal tissues. These results suggest that the immunohistochemical detection of MT and AP-N could provide useful information as a pathological diagnostic tool for classifying renal cancer and surrounding tissues.

Biomarkers, Tumor↗
PubMed2001

Endopolygalacturonase is essential for citrus black rot caused by Alternaria citri but not brown spot caused by Alternaria alternata.

Alternaria citri, the cause of Alternaria black rot, and Alternaria alternata rough lemon pathotype, the cause of Alternaria brown spot, are morphologically indistinguishable pathogens of citrus: one causes rot by macerating tissues and the other causes necrotic spots by producing a host-selective toxin. To evaluate the role of endopolygalacturonase (endoPG) in pathogenicity of these two Alternaria spp. pathogens, their genes for endoPG were mutated by gene targeting. The endoPGs produced by these fungi have similar biochemical properties, and the genes are highly similar (99.6% nucleotide identity). The phenotypes of the mutants, however, are completely different. An endoPG mutant of A. citri was significantly reduced in its ability to cause black rot symptoms on citrus as well as in the maceration of potato tissue and could not colonize citrus peel segments. In contrast, an endoPG mutant of A. alternata was unchanged in pathogenicity. The results indicate that a cell wall-degrading enzyme can play different roles in the pathogenicity of fungal pathogens. The role of a cell wall-degrading enzyme depends upon the type of disease but not the taxonomy of the fungus.

Alternaria↗
PubMed2001

Functional relevance of human adh polymorphism.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were C. J. Peter Eriksson and Tatsushige Fukunaga. The presentations were (1) 4-Methylpyrazole as a tool in the investigation of the role of ADH in the actions of alcohol in humans, by Taisto Sarkola and C. J. Peter Eriksson; (2) ADH2 polymorphism and flushing in Asian populations, by Wei J. Chen, C. C. Chen, J. M. Ju, and Andrew T. A. Cheng; (3) Role of ADH3 genotypes in the acute effects of alcohol in a Finnish population, by Hidetaka Yamamoto, Kathrin Kohlenberg-Müller, and C. J. Peter Eriksson; (4) Clinical characteristics and disease course of alcoholics with different ADH2 genotypes, by Mitsuru Kimura, Masanobu Murayama, Sachio Matsushita, Haruo Kashima, and Susumu Higuchi; (5) ADH2 polymorphism, alcohol drinking, and birth defects, by Lucinda Carr, D. Viljoen, L. Brooke, T. Stewart, T. Foroud, J. Su, and Ting-Kai Li; and (6) ADH genotypes and alcohol use in Europeans, by John B. Whitfield.

Adult↗
PubMed2001

Surgical treatment for pancreatic metastasis from soft-tissue sarcoma: report of two cases.

We present two cases in which a soft-tissue sarcoma metastasized to the pancreas, but both patients survived as a result of repetitive surgical treatment during a 6- to 10-year period. The first case was a 29-year-old man who had a history of removal of mesenchymal chondrosarcoma in the left thigh in 1986 and who underwent distal pancreatectomy and the enucleation of a tumor in the head of the pancreas because of the development of three metastatic lesions in 1989. Afterward, although metastases were found in other organs, they were resected each time (for a total of five times) and the patient has survived over 10 years. The second case was a 40-year-old woman who had a history of the removal of synovial sarcoma in the right thigh and had 6 surgical resections of local or pulmonary recurrent tumors. She underwent pylorus-preserving pancreaticoduodenectomy in 1993 because of the development of a solitary metastatic lesion in the pancreas and survived more than 6 years after the pancreatectomy. Our report suggests, in selected cases, that long-term survival from pancreatic metastasis of soft-tissue sarcoma is expected as a result of curative resection. However, because pancreatic metastasis has a potential to recur in other organs, it is necessary to take aggressive surgical procedures repeatedly for the treatment of recurrences to improve prognosis after pancreatectomy.

Adult↗
PubMed2001

Lymph node metastasis from hilar cholangiocarcinoma: audit of 110 patients who underwent regional and paraaortic node dissection.

OBJECTIVE: To assess the status of the regional and paraaortic lymph nodes in hilar cholangiocarcinoma and to clarify the efficacy of systematic extended lymphadenectomy. SUMMARY BACKGROUND DATA: There have been no studies in which regional and paraaortic lymphadenectomies for hilar cholangiocarcinoma have been routinely performed. Therefore, the metastasis rates to the regional and paraaortic nodes, the mode of lymphatic spread, and the effect of extended lymph node dissection on survival remain unknown. METHODS: This study involved 110 patients who underwent surgical resection for hilar cholangiocarcinoma with lymph node dissection including both the regional and paraaortic nodes. A total of 2,652 nodes retrieved from the surgical specimens were examined microscopically. RESULTS: Of the 110 patients, 52 (47.3%) had no involved nodes, 39 (35.5%) had regional lymph node metastases, and 19 (17.3%) had regional and paraaortic node metastases. The incidence of positive nodes was significantly higher in the patients with pT3 disease than in those with pT2 disease. The pericholedochal nodes were most commonly involved (42.7%), followed by the periportal nodes (30.9%), the common hepatic nodes (27.3%), and the posterior pancreaticoduodenal nodes (14.5%). The celiac and superior mesenteric nodes were rarely involved. The 3-year and 5-year survival rates were 55.4% and 30.5% for the 52 patients without involved nodes, 31.8% and 14.7% for the 39 patients with regional node metastases, and 12.3% and 12.3% for the 19 patients with paraaortic node metastases, respectively. Of the 19 patients with positive paraaortic nodes, 7 had no macroscopic evidence of paraaortic disease on intraoperative inspection. The survival in this group was significantly better than in the remaining 12 patients. CONCLUSION: The paraaortic nodes and the regional nodes are frequently involved in advanced hilar cholangiocarcinoma. Whether extended lymph node dissection provides a survival benefit requires further study. However, the fact that long-term survival is possible despite pN2 or pM1 disease encourages the authors to perform an aggressive surgical procedure with extended lymph node dissection in selected patients with hilar cholangiocarcinoma.

Aorta↗
PubMed2001

Coronary artery motion during the cardiac cycle and optimal ECG triggering for coronary artery imaging.

RATIONALE AND OBJECTIVES: Our purpose was to investigate the motion characteristics of the coronary arteries and determine optimal electrocardiographic (ECG) trigger time during the cardiac cycle to minimize motion artifacts. METHODS: Contrast-enhanced multislice movie studies of electron beam tomography (EBT) images were performed on 70 subjects. The EBT datasets, which covered an entire cardiac cycle at 58-ms intervals, were acquired for a short-axis view of the heart with ECG triggering. The pixel values along x and y axes were measured at multiple intervals during the cardiac cycle to establish the motion distance and velocity of three major coronary arteries. RESULTS: Coronary artery motion varied greatly throughout the cardiac cycle in three major coronary arteries and increased with the patient's baseline heart rate. The greatest and lowest velocities of coronary arterial movement during the cardiac cycle were determined. Based on the lowest velocity of right coronary artery movement during the cardiac cycle, the optimal ECG trigger times were located at approximately 35% (31.4%-37.6%) or 70% (68.7%-71.4%) of the R-R interval in patients whose resting heart rate was < or =70 beats per minute (bpm); at 50% (47.2%-61.1%) of the R-R interval in the 71- to 100-bpm group; and at 55% (52.8%-59.1%) of the R-R interval in the >100-bpm group. Our data demonstrated that the motion characteristics of the left circumflex artery were quite similar to those of the right coronary artery and that the left anterior descending coronary artery had no significant differences in motion throughout the cardiac cycle. A minimum scan speed of 35.4 to 75.5 ms per slice is needed to completely diminish cardiac motion artifacts (in-plane coronary artery motion with <1-mm displacement). CONCLUSIONS: For coronary artery screening, the optimal ECG trigger time should be determined according to the patient's heart rate, thus greatly reducing motion and motion artifacts during 100-ms acquisitions.

Adult↗
PubMed2001

Proposal of Sphingomonas wittichii sp. nov. for strain RW1T, known as a dibenzo-p-dioxin metabolizer.

A polyphasic taxonomic study was performed on Sphingomonas sp. strain RW1T. The organism was isolated from water of the River Elbe and has been known as a potent metabolizer of dibenzo-p-dioxin and its relatives. TLC of a mild alkaline hydrolysate of extractable cellular lipids of strain RW1T and type strains of 21 Sphingomonas species gave a spot of sphingoglycolipid (SGL)-1 (glucuronosyl ceramide), which is characteristic of sphingomonads. In addition, strain RW1T and type strains of three Sphingomonas species (Sphingomonas yanoikuyae, Sphingomonas terrae and Sphingomonas macrogoltabidus) showed a second spot of SGL (SGL-1') identified as galacturonosyl ceramide. The presence of SGL-1 in cellular lipids suggested that strain RW1T is a member of the genus Sphingomonas. DNA-DNA reassociation rates between strain RW1T and each type strain of 14 Sphingomonas species including Sphingomonas paucimobilis, type species for the genus, revealed that strain RW1T is independent from these species. Results of phylogenetic analysis of 16S rDNA sequences of strain RW1T and type strains of 21 named Sphingomonas species verified that strain RW1T belongs to the genus Sphingomonas. Strain RW1T could be differentiated from named species of the genus by phenotypic characteristics and has been assigned to a new species, Sphingomonas wittichii sp. nov. The type strain is DSM 6014T (= JCM 10273T = EY 4224T). DNA G+C content is 67 mol %.

Bacterial Typing Techniques↗
PubMed2001

Relatedness between the coagulase gene 3'-end region and coagulase serotypes among Staphylococcus aureus strains.

The 3'-end region of the coagulase gene from 22 strains of Staphylococcus aureus including 10 standard serotype strains was sequenced, and five subgroups with 4-8 tandem repeating units were distinguished among the tested strains. Phylogenetic analysis of the 3'-end region of the coagulase gene indicated that strains belonging to the same serotype were clustered in the same branch. A phylogenetic tree of the deduced amino acid sequences revealed that the C-terminal region might not be responsible for the epitope of the coagulase protein.

Bacteriological Techniques↗
PubMed2001

Antisense display: a new method for functional gene screen and its application to angiogenesis-related gene isolation.

We have developed an antisense-oriented method for functional gene screening, which we termed "antisense display." After evaluation in a cell-free system, we applied this method to a cellular system for isolating angiogenesis-related genes and came across a gene previously not described in humans. A screen of 10 mer antisense repertoire led to the identification of a unique 'angiostatic' antisense, and the gene corresponding to it was found to be preferentially expressed in vascular endothelial cells, coding for a putative type-2 membrane protein containing Rab-GAP/TBC and EF-hand-like domains. We named it vascular Rab-GAP/TBC domain-containing protein (VRP). The results obtained thus indicate that the antisense display method is useful for the isolation of functional genes responsible for phenotypes concerned.

Genetic Testing↗
PubMed2001

[A case of rhabdomyolysis associated with influenza A viral infection given an useful early diagnosis by Tc-99m bone agent scintigraphy].

Rhabdomyolysis is a syndrome resulting from skeletal muscle injury with release of muscle cell contents into the plasma. It is often associated with alcohol abuse, muscle compression and generalized seizure. It may also follow viral infections like influenza. Tecnetium-99m phosphate compounds are useful for bone scintigraphy. But proper interpretation of this bone agent scintigrams must include careful analysis of extraskeletal accumulations, such as cerebrospinal lesions, carcinoma, acute myocardial infarction, myocarditis and inflammatory myopathy. This case was a 74-year-old female who developed rhabdomyolysis associated with influenza A viral infection. We report the usefulness of Tecnetium-99m phosphate scintigraphy for early diagnosis, location and extent of the muscle damage of viral induced rhabdomyolysis.

Aged↗
PubMed2001

[Detection of mupirocin resistant staphylococci from patients treated with mupirocin].

Susceptibility testing of mupirocin (MUP) was performed by an agar dilution method according to the National Committee for Clinical Laboratory Standard (NCCLS) to detect the MUP resistance. A total of 434 isolates of methicillin-resistant staphylococci were examined and all of 205 isolates of methicillin-resistant Staphylococcus aureus (MRSA) from 43 hospitals nationwide in 1993 were sensitive to MUP. However, MUP resistance emerged among 228 isolates [185 isolates (88 cases) of MRSA and 43 isolates (28 cases) of methicillin-resistant coagulase negative staphylococci (MR-CNS)] from nasal swabs of patients with MUP treatment between Sep 1996 and Feb 2000 in the Nagoya University Hospital. The high-level MUP resistance (MIC > or = 512 micrograms/mL) was isolated from two patients, one isolate of MRSA and four of S. hominis, respectively. Low-level MUP resistance (MIC 8-128 micrograms/mL) was isolated from three patients, 11 isolates of MRSA, one of S. chromogenes and five of S. epidermidis, respectively. The mupA which encodes the MUP resistant isoleucyl-tRNA synthetase (IRS) were investigated by PCR in these MUP resistant isolates. The mupA was detected only in high-level MUP resistant S. hominis, but not detected in high-level MUP resistant MRSA and low-level MUP resistant isolates. We also investigated the characteristics of the patients with MUP resistance. All of MUP resistant staphylococci were isolated after initiation of MUP treatment. Four patients with MUP resistant MRSA and low-level MUP resistant MR-CNS had MRSA infectious disease and MUP resistant strains were successfully eradicated with vancomycin treatment in two patients. MUP high-level resistant S. hominis, has emerged after MUP treatment for eradication of MRSA. Clinical guidelines for the prudent use of MUP should be generally adopted with careful monitoring of emergence of MUP resistance.

Adult↗
PubMed2001

Regulation of the glv operon in Bacillus subtilis: YfiA (GlvR) is a positive regulator of the operon that is repressed through CcpA and cre.

Maltose metabolism and the regulation of the glv operon of Bacillus subtilis, comprising three genes, glvA (6-phospho-alpha-glucosidase), yfiA (now designated glvR), and glvC (EIICB transport protein), were investigated. Maltose dissimilation was dependent primarily upon the glv operon, and insertional inactivation of either glvA, glvR, or glvC markedly inhibited growth on the disaccharide. A second system (MalL) contributed to a minor extent to maltose metabolism. Northern blotting revealed two transcripts corresponding to a monocistronic mRNA of glvA and a polycistronic mRNA of glvA-glvR-glvC. Primer extension analysis showed that both transcripts started at the same base (G) located 26 bp upstream of the 5' end of glvA. When glvR was placed under control of the spac promoter, expression of the glv operon was dependent upon the presence of isopropyl-beta-D-thiogalactopyranoside (IPTG). In regulatory studies, the promoter sequence of the glv operon was fused to lacZ and inserted into the amyE locus, and the resultant strain (AMGLV) was then transformed with a citrate-controlled glvR plasmid, pHYCM2VR. When cultured in Difco sporulation medium containing citrate, this transformant [AMGLV(pHYCM2VR)] expressed LacZ activity, but synthesis of LacZ was repressed by glucose. In an isogenic strain, [AMGLVCR(pHYCM2VR)], except for a mutation in the sequence of a catabolite-responsive element (cre), LacZ activity was expressed in the presence of citrate and glucose. Insertion of a citrate-controlled glvR plasmid at the amyE locus of ccpA(+) and ccpA mutant organisms yielded strains AMCMVR and AMCMVRCC, respectively. In the presence of both glucose and citrate, AMCMVR failed to express the glv operon, whereas under the same conditions high-level expression of both mRNA transcripts was found in strain AMCMVRCC. Collectively, our findings suggest that GlvR (the product of the glvR gene) is a positive regulator of the glv operon and that glucose exerts its effect via catabolite repression requiring both CcpA and cre.

Bacillus subtilis↗
PubMed2001

Axin facilitates Smad3 activation in the transforming growth factor beta signaling pathway.

Axin acts as a negative regulator in Wnt signaling through interaction with various molecules involved in this pathway, including beta-catenin, adenomatous polyposis coli, and glycogen synthase kinase 3beta. We show here that Axin also regulates the effects of Smad3 on the transforming growth factor beta (TGF-beta) signaling pathway. In the absence of activated TGF-beta receptors. Axin physically interacted with Smad3 through its C-terminal region located between the beta-catenin binding site and Dishevelled-homologous domain. An Axin homologue, Axil (also called conductin), also interacted with Smad3. In the absence of ligand stimulation, Axin was colocalized with Smad3 in the cytoplasm in vivo. Upon receptor activation, Smad3 was strongly phosphorylated by TGF-beta type I receptor (TbetaR-I) in the presence of Axin, and dissociated from TbetaR-I and Axin. Moreover, the transcriptional activity of TGF-beta was enhanced by Axin and repressed by an Axin mutant which is able to bind to Smad3. Axin may thus function as an adapter of Smad3, facilitating its activation by TGF-beta receptors for efficient TGF-beta signaling.

Adaptor Proteins, Signal Transducing↗