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Biomedical subjects

S Tamura

Publications and source records attributed to S Tamura.

At least 469 records · Page 26Linked to original sources
PubMed1992

[Coronary artery bypass grafting by utilizing the artery grafts and bovine internal thoracic artery graft (Bioflow in an elderly patient)].

We performed coronary artery bypass grafting (CABG) in a 80-year-old male with calcified ascending aorta and severe varicose veins utilizing the bilateral internal thoracic arteries and the right gastroepiploic artery under fibrillatory arrest without aortic cross-clamp (aortic no-touch technique). After triple coronary artery bypass grafting was completed, heart failure occurred. Additional Bioflow graft to the circumflex artery restored good cardiac function. The aortic no-touch technique is a useful method for CABG in patients with severe calcified ascending aorta. This experience suggests that the Bioflow graft is a helpful conduit at an urgent situation in CABG.

Aged↗
PubMed1992

A simple procedure for intrahepatic biliary drainage in patients with obstructive jaundice owing to a recurrence of cancer following reconstructive gastric surgery.

We designed a simple and reliable method of intrahepatic biliary drainage for patients with obstructive jaundice owing to a recurrent gastric cancer. This approach can be used for selected patients treated by partial gastrectomy and reconstructive surgery, using the Billroth II procedure and antecolic anastomosis. Anastomosis between the intrahepatic bile duct and the afferent jejunal loop is performed at the anterior edge of the liver, thus facilitating the prevention of recurrence of jaundice caused by tumor infiltration. Application of this technique led to a long-term palliation, control of the jaundice and a fairly normal life.

Adult↗
PubMed1991

Mechanisms of hypoxic and aerobic cytotoxicity of mitomycin C in Chinese hamster V79 cells.

Mitomycin C (MMC) induced aerobic and hypoxic cytotoxicity in Chinese hamster V79 cells was studied to evaluate the role of the 1-electron versus 2-electron reductive bioactivation. Superoxide dismutase, catalase, and desferal had no protective effects on the aerobic or hypoxic cytotoxicity of MMC, whereas Tempol and Tempol-H, which are known to interrupt and terminate radical reactions, provided partial protection under aerobic conditions. However, under hypoxic conditions, Tempol provided complete protection whereas Tempol-H was ineffective. Electron paramagnetic resonance and spin-trapping investigations, designed to study the mechanisms of such protective effects, confirmed that MMC is activated by the human NADPH:cytochrome P-450 oxidoreductase to its semiquinone radical and that, under aerobic conditions, the semiquinone radical reduces molecular oxygen. Under hypoxic conditions, the semiquinone of MMC reduces H2O2 to produce OH radicals as detected by electron paramagnetic resonance-spin trapping with 5,5-dimethyl-1-pyrroline N-oxide. The 1-electron reduced product of MMC was also found to reduce Tempol to the hydroxylamine, Tempol-H, whereas oxidation of Tempol-H by MMC-. was negligible. Cell survival studies and electron paramagnetic resonance observations indicate that the hypoxic cytotoxicity of MMC is mediated by 1-electron activation to its semiquinone intermediate. Under aerobic conditions, the steady state concentration of this intermediate is low due to the facile autooxidation of the semiquinone producing O2-. and H2O2 which are capable of causing oxidative cytotoxicity. Tempol, which can accept an electron from reducing radical species, completely inhibited the hypoxic cytotoxicity of MMC indicating MMC-., the semiquinone of MMC as the species responsible for DNA alkylation and selective hypoxic cytotoxicity of MMC. Our results also indicate that the aerobic cytotoxicity is mediated by other processes in addition to the 1-electron mediated activation.

Aerobiosis↗
PubMed1991

The rat H+/K(+)-ATPase beta subunit gene and recognition of its control region by gastric DNA binding protein.

The rat gastric H+/K(+)-ATPase beta subunit gene was cloned, and its nucleotide sequence was determined. The coding region is separated by 6 introns, whereas the related human Na+/K(+)-ATPase beta subunit gene was shown to have 5 introns (Lane, L.K., Shull, M.M., Whitmer, K.R., and Lingrel, J.B. (1989) Genomics 5, 445-453). The positions of introns 1, 2, and 5 of the two genes were the same. The similarities in intron/exon organizations and primary structures (30-40% identical residues) suggest that the beta subunit genes for H+/K(+)-ATPases were derived from a common ancestor. The upstream region of the rat H+/K(+)-ATPase beta subunit gene contains direct repeat sequences and palindromes, potential binding sites for RNA polymerase II and E4TF1, and CACCC box sequences. Gel retardation assay demonstrated that the stomach, but not other tissues (liver, brain, kidney, spleen, and lung), has a nuclear protein(s) capable of binding to the regions upstream of the potential RNA polymerase II binding sites (TATA box). The nuclear protein(s) are suggested to recognize three tandem GATAGC sequences and may be important for controlled transcription of the H+/K(+)-ATPase beta subunit gene in gastric parietal cells.

Adenosine Triphosphatases↗
PubMed1991

Enhancement of the protective qualities of gastric mucus by sucralfate: role of phosphoinositides.

The effects of intragastric administration of sucralfate on the physicochemical properties of gastric mucus, and the mechanism of its protective action against alcohol-induced mucosal injury were investigated using in vivo and in vitro models. The experiments in vivo were conducted with groups of rats receiving a dose of 100 mg sucralfate twice daily for 5 consecutive days. The animals were sacrificed 16 hours after the last dose, their stomachs dissected, and the mucosa subjected to physicochemical measurements. In the in vitro studies, gastric mucosa was cultured in the presence of sucralfate, ethanol, or both. The in vivo results revealed that sucralfate elicited an 8% increase in mucus gel dimension, while its sulfo- and sialomucin content increased by 63% and 81%, respectively. The changes in mucus gel mucin content with sucralfate were accompanied by a 9.5% increase in mucus hydrogen ion (H+) retardation capacity, 1.9-fold increase in viscosity, and a 60% increase in the gel hydrophobicity. The mucus elaborated in the presence of sucralfate exhibited 14% lower protein content and 62% higher content of carbohydrate than that of control, and contained more neutral lipids. Furthermore, the gastric mucus of the sucralfate group showed a marked increase in mucus glycoprotein polymeric form. The data obtained with gastric mucosal culture demonstrated that sucralfate elicited a significant increase in mucin synthesis, which was reflected in the enhanced metabolism of mucosal phosphoinositides. In contrast, ethanol, which exhibited detrimental effects on mucin synthesis, also caused alterations in the phosphoinositide signal pathway. The changes in mucin and phosphoinositide distribution patterns evoked by ethanol were prevented by sucralfate. Our results suggest that the mucosal strengthening action of sucralfate occurs through the stimulation of the metabolism of phosphoinositide-derived messenger molecules.

Animals↗
PubMed1991

Elevated levels of transforming growth factor beta messenger RNA and its polypeptide in human hepatocellular carcinoma.

Malignant cells in culture express elevated levels of transforming growth factor beta 1 (TGF-beta 1) mRNA and secrete an abundant amount of TGF-beta protein, but little is known about the production of TGF-beta in human malignant tissues in vivo. We estimated the levels of TGF-beta 1 mRNA expression by Northern hybridization and measured TGF-beta protein using a radioreceptor assay in tumor tissues surgically obtained from six patients with hepatocellular carcinoma (HCC). TGF-beta 1 mRNA was expressed at much higher levels in HCC tissues from all the cases compared with normal human liver, suggesting an association of the activated TGF-beta 1 gene transcription with hepatocarcinogenesis. The content of TGF-beta was 207 +/- 121 ng/g wet tissue in the HCC tissue, and it showed correlation with the level of TGF-beta 1 mRNA in the tissue (r = 0.69; P less than 0.05). An immunohistochemical study demonstrated that TGF-beta 1 staining could be observed in HCC cells. These observations suggest that human HCC strongly expresses TGF-beta 1 mRNA in vivo, leading to a high content of TGF-beta protein.

Aged↗
PubMed1991

Identity of mucin's "118-kDa link protein" with fibronectin fragment.

Human and rat intestinal mucin was purified by equilibrium density gradient centrifugation and Sepharose 2B chromatography according to M. Mantle, D. Mantle, and A. Allen (1981, Biochem. J. 195, 277-285) and analyzed using mucin, DNA, and fibronectin-specific antibodies in dot-blot, ELISA, and Western blotting. The 118-kDa component of the mucins and the 118-kDa fragment of fibronectin from the same source displayed affinity for concanavalin A and immunoreacted with fibronectin antibodies. The amino acid and carbohydrate compositions of the 118-kDa peptide electroeluted by gel electrophoresis of mucin and fibronectin preparations were identical within each pair of glycopeptides and closely resembled the "link protein component" of human and rat intestinal mucin preparations of R. E. F. Fahim, R. D. Specian, G. G. Forstner, and J. F. Forstner (1987, Biochem. J. 243, 631-640) and M. Mantle and G. Stewart (1989, Biochem. J. 259, 631-640). We therefore conclude that the "link protein" claimed to be an integral part of mucus glycoproteins in actuality is the 118-kDa fragment of fibronectin.

Amino Acids↗
PubMed1991

Control region and gastric specific transcription of the rat H+,K(+)-ATPase alpha subunit gene.

The rat gastric H+,K(+)-ATPase alpha subunit gene was cloned and the nucleotide sequence of its 5'-upstream region was determined. Sequence comparison with the corresponding part of the human gene indicated the presence of highly conserved regions which may be important for specific transcription of the alpha subunit in gastric parietal cells. The amino-terminal sequence (Met-Gly-Lys-Ala-Glu-) of the rat enzyme was similar to those of the pig and human enzymes. The gene organization of the rat enzyme was also similar to that of the human gene: introns 1, 2 and 9 were located in exactly the same positions as those in the human gene, and, as in the latter, exon 6 was not separated by an intron. The sequences of introns 1 and 2 were highly conserved among the rat, human and pig genes, but were entirely different from those of Na+,K(+)-ATPase catalytic subunit genes. Northern blot hybridization indicated that the gene was transcribed only in gastric mucosa.

Adenosine Triphosphatases↗
PubMed1991

Immunohistologic detection of the epidermal growth factor receptor in human esophageal squamous cell carcinoma.

Epidermal growth factor receptor (EGF-R) expression was studied immunohistologically in 38 patients with esophageal squamous cell carcinoma. The EGF-R was faintly expressed in basal and parabasal layers of normal esophageal epithelia and in cancer nests of 20 patients; it was strongly expressed in all areas of dysplastic epithelia and in cancer nests of 18 patients. The patients with strongly expressed EGF-R had lymph node metastases more frequently, and their prognosis was poorer than those with faintly expressed EGF-R. The EGF-R expression showed a mosaic pattern in 17 patients and a diffuse pattern in 21 patients. The patients with a mosaic pattern had lymph node metastases more frequently and a worse prognosis than those with a diffuse pattern. Expression of EGF-R in metastatic lymph nodes was similar to that in strongly expressing areas of primary cancers with a mosaic pattern. Thus EGF-R expression may be an important indicator for malignancies of esophageal squamous cell carcinomas because primary cancer cells with strongly expressed EGF-R metastasize to lymph nodes more frequently.

Adult↗
PubMed1991

Cross-protection against influenza A virus infection by passively transferred respiratory tract IgA antibodies to different hemagglutinin molecules.

Mice that were intranasally immunized with different influenza A virus hemagglutinins (HA), derived from PR8 (H1N1), A/Yamagata (H1N1) or A/Fukuoka (H3N2) virus, together with cholera toxin B subunit as an adjuvant, were examined for protection against PR8 infection; PR8 HA and A/Yamagata HA immunization conferred complete protection, while A/Fukuoka HA immunization failed to confer protection. In parallel with protection, PR8 HA-, A/Yamagata HA-, and A/Fukuoka HA-immunized mice produced a high, a moderate and a low level of PR8 HA-reactive IgA in the respiratory tract, respectively. These IgA antibodies were not only higher in content in the nasal secretions, but also more cross-reactive than IgG. The purified IgA antibodies from respiratory tract washings of PR8 HA-immunized mice, which contained the HA-specific IgA corresponding to the amount detected in the nasal wash, were able to protect mice from PR8 challenge when transferred to the respiratory tract of naive mice. The transfer of IgA from A/Yamagata HA-immunized mice also afforded cross-protection against PR8 infection, whereas the IgA from A/Fukuoka HA-immunized mice failed to provide protection. The ability of transferred IgA to prevent viral infection was dependent on the amount of HA-reactive IgA remaining in the respiratory tract of the host at the time of infection. These experiments directly demonstrate that IgA antibodies to influenza A virus HA by themselves play a pivotal role in defence not only against homologous virus infection, but also against heterologous drift virus infection at the respiratory mucosa, the portal of entry for the viruses.

Animals↗
PubMed1991

Prognostic factors in Japanese patients with colorectal cancer: the significance of large bowel obstruction--univariate and multivariate analyses.

In order to define prognostic factors in colorectal carcinoma, univariate and multivariate analyses were carried out on data from 113 Japanese patients treated in a typical general hospital in Japan. In the univariate analysis, a poor prognosis was seen in those with poorly differentiated adenocarcinoma, in tumors that perforated the visceral peritoneum or that invaded directly other organs or structures (T4), in metastasis to the nodes along the main vascular pedicle (N3), in lymphatic permeation, in blood vessel invasion, in peritoneal dissemination, in Dukes C stage, and in those with lesions presenting with large bowel obstruction. Of these, only lymph node metastasis and peritoneal dissemination had an independent prognostic significance when a multivariate Cox analysis was performed. The significant risk factors related to an obstructing tumor were determined by multivariate logistic regression analysis. The significant variables were patient's age, nodal involvement and peritoneal dissemination. Since lymph node metastasis and peritoneal dissemination proved significant in both multivariate analyses, we propose that the presence of large bowel obstruction is not an independent prognostic factor in patients with colorectal carcinoma. In poor-risk patients who have an obstructing tumor, a staged operation should be attempted for definitive curative surgery.

Adenocarcinoma↗
PubMed1991

DNA diagnosis of hydatidiform mole using the polymerase chain reaction.

We have used the polymerase chain reaction (PCR) technique for the diagnosis of hydatidiform mole, a trophoblastic disease. For this, we targeted the hypervariable 3' flanking region of the APOB gene (APOB/VNTR) because of its high heterozygosity index (0.61) in the Japanese population. We examined seven clinical cases which were tentatively diagnosed as hydatidiform moles. Five of these revealed DNA segments unique to the paternal APOB allele, allowing us to diagnose a complete mole. The PCR technique for targeting the APOB/VNTR appears useful for early diagnosis of hydatidiform mole.

Alleles↗
PubMed1991

The ventilatory threshold gives maximal lactate steady state.

The purpose of this study was to examine whether the ventilatory threshold (Thv) would give the maximal lactate steady state ([la]ss, max), which was defined as the highest work rate (W) attained by a subject without a progressive increase in blood lactate concentration [la]b at constant intensity exercise. Firstly, 8 healthy men repeated ramp-work tests (20 W.min-1) on an electrically braked cycle ergometer on different days. During the tests, alveolar gas exchange was measured breath-by-breath, and the W at Thv (WThv) was determined. The results of two-way ANOVA showed that the coefficient of variation of a single WThv determination was 2.6%. Secondly, 13 men performed 30-min exercise at WThv (Thv trial) and at 4.9% above WThv (Thv + trial), which corresponded to the 95% confidence interval of the single determination. The [la]b was measured at 15 and 30 min from the onset of exercise. The [la]b at 15 min (3.15 mmol.l-1, SEM 0.14) and at 30 min (2.95 mmol.l-1, SEM 0.18) were not significantly different in Thv trial. However, the [la]b of Thv + trial significantly increased (P less than 0.05) from 15 min (3.62 mmol.l-1, SEM 0.36) to 30 min (3.91 mmol.l-1, SEM 0.40). These results indicate that Thv gives the [la]ss, max, at which one can perform sustained exercise without continuous [la]b accumulation.

Adult↗
PubMed1991

Pulmonary vascular involvement in sarcoidosis: granulomatous angiitis and microangiopathy in transbronchial lung biopsies.

To evaluate the occurrence of granulomatous angiitis and microangiopathy in the lung with sarcoidosis, transbronchial lung biopsy specimens were examined from 174 cases with sarcoidosis. Granulomatous angiitis was seen in 72 cases, which corresponded to 53% of the cases with granulomata. Granulomatous angiitis showed venous involvement (65%), both venous and arterial involvement (24%) or arterial involvement only (11%). There was no significant difference in occurrence of granulomatous angiitis between upper and lower lobes. The cases with granulomatous angiitis in the lung had a higher frequency of ophthalmic symptoms and elevated serum angiotensin converting enzyme level. Basal lamina layering in the microvasculature was more often observed in the bronchial mucosa than in the alveolar walls and is not exclusively related to granulomata. Endothelial proliferation and basal lamina alterations in granulomatous angiitis may be closely associated with granulomas. The present study revealed coexistence of granulomatous angiitis and microangiopathy in the lung with sarcoidosis and suggests that both may participate in the development of pulmonary sarcoidosis.

Biopsy↗