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Biomedical subjects

K Miwa

Publications and source records attributed to K Miwa.

At least 163 records · Page 9Linked to original sources
PubMed1997

Section of the vagal celiac branch in man reduces glucagon-stimulated insulin release.

The purpose of this study was to determine whether section of the celiac branch of the vagus nerve in man affects the insulin response to intravenous glucagon injection. Patients who received a subtotal gastrectomy with lymph node dissection for gastric carcinoma were divided into two groups: the celiac-preserved group (n = 16) and the celiac-sectioned group (n = 13). The hepatic branches of the vagus were preserved in both groups. The glucagon test was performed twice in each patient during the operation; before and after manipulation of the celiac branch. Blood samples were collected just before and 6 min after the injection. No difference in the mean increases in blood glucose, insulin and C-peptide levels were seen between the two groups before the nerve manipulation. In the celiac-preserved group, the glucagon stimulated glucose-related C-peptide ratio (x 10(-3) was 0.5 +/- 0.7 before the nerve manipulation and 3.5 +/- 3.0 after it, a significant difference (p < 0.01). In the celiac-sectioned group, this increase was not observed, the ratio was 0.7 +/- 0.6 before the nerve manipulation and 0.8 +/- 3.4 after. These results indicate that the vagal celiac branch in man may also be involved in the control of pancreatic insulin release.

Adult↗
PubMed1997

Genomic organization and characterization of the gene encoding bovine prostaglandin F2alpha receptor.

We isolated genomic clones for bovine prostaglandin (PG) F2alpha receptor by the standard plaque hybridization method, using the cDNA fragments of bovine PGF2alpha receptor (PGF2alphaR) as probe DNAs. The coding regions of this receptor gene were interspersed by a large intron sequence (33 kb) at the splice junction in the sixth transmembrane domain. The 5'-RACE experiments revealed two alternative transcription start points (tsp), indicating the existence of two potential promoter regions. The major promoter, which was named promoter region A, was located upstream of exon 1 and lacked the typical TATA sequence and CAAT box but had three GC boxes with an overall high GC content. Another putative promoter, region B, was found upstream of exon 2 and had both a TATA-like sequence and a CAAT-like box with several potential binding sites for transcription factors. Southern blot analysis indicated that a single copy gene in the haploid genome encodes PGF2alphaR. Promoter activities of these two putative promoter regions were assayed in the bovine luteal cells, and one of them (promoter region A) was activated by phorbol 12-myristate 13-acetate (TPA) treatment.

Amino Acid Sequence↗
PubMed1997

Gustatory receptor cell responses to the sweeteners, monellin and thaumatin.

Mouse gustatory responses to sucrose, monellin and thaumatin were examined extracellularly from the chorda tympani nerve and intracellularly from individual taste receptor cells. Although monellin and thaumatin taste intensely sweet to humans and old-world monkeys, they do not appear to elicit chorda tympani nerve responses in rats and other mammals. However, there is considerable species variation in the taste responses of mammals, including differences in taste responses of different strains of mice. In the present study with Slc:ICR mice, we show that chorda tympani and taste receptor cell response profiles, and behavioral results for monellin and thaumatin, are similar to response profiles for sucrose.

Animals↗
PubMed1997

Binding of 8-mer to 11-mer peptides carrying the anchor residues to slow assembling HLA class I molecules (HLA-B*5101).

The binding of 303 8-mer to 11-mer peptides carrying the anchor residues at P2 and the C-terminus to HLA-B*5101 molecules was examined by a stabilization assay in which peptides were incubated with RMA-S-B*5101 cells at 26 degrees C for 3 h. Analysis of the binding of these peptides to HLA-B*5101 molecules showed that Pro and Ala at P2, and Ile, Val, and Leu at the C-terminus functioned as anchor residues, while Gly at P2 and Met at the C-terminus were weak anchors. Pro was a stronger anchor residue than Ala at P2, while Ile was the strongest anchor at the C-terminus. Among 8-mer to 11-mer peptides, the 9-mer peptides showed the strongest binding to HLA-B*5101 molecules. This is in contrast to our recent findings that 10-mer and 11-mer peptides bind to HLA-B*3501 molecules as effectively as 9-mer peptides. Since both HLA class I molecules have the same B-pocket and the binding peptides carry the same anchor residues, it is assumed that the structure of the F-pocket may restrict the length of binding peptides. The ability of HLA-B*5101 binding peptides to stabilize the HLA-B*5101 molecules was markedly lower than that of HLA-B*3501 binding peptides to stabilize the HLA-B*3501 molecules. It is known that HLA-B*5101 is a slow assembling molecule, while HLA-B*3501 assembles rapidly. The results imply that the slow assembling of HLA-B*5101 molecules results from the low affinity of peptides to HLA-B*5101 molecules.

Cell Line↗
PubMed1997

Soluble E-selectin, ICAM-1 and VCAM-1 levels in systemic and coronary circulation in patients with variant angina.

OBJECTIVE: The purpose of this study was to assess whether the plasma levels of soluble adhesion molecules including E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are elevated in patients with variant angina and whether they are released in the coronary circulation. METHODS: Antecubital venous plasma samples were collected from 33 patients with variant angina, 22 patients with stable effort angina and 20 control subjects. Samples were also collected from the aortic root (AO) and the coronary sinus (CS) in 18 patients with variant angina before and after left coronary spasm induced by intracoronary injection of acetylcholine. The soluble adhesion molecules were assayed by enzyme immunoassay. RESULTS: Antecubital venous plasma soluble E-selectin (P < .05), ICAM-1 (P < .01) and VCAM-1 (NS) levels were higher in the variant angina group than in the control group, respectively. The plasma soluble ICAM-1 level was also higher (P < .01) in the variant angina group than in the stable effort angina group. In the variant angina group, both soluble ICAM-1 (P < .05) and VCAM-1 (P < .01) levels were significantly lower in CS than AO at baseline. In contrast, after the spasm the plasma soluble ICAM-1 level was (P < .05) higher in CS than AO and the CS-AO differences of soluble ICAM-1 (P < .05) and VCAM-1 (P < .05) increased as compared with the baseline, respectively. These values were remained unchanged in the stable effort angina group after rapid atrial pacing and in the control group after administration of acetylcholine. CONCLUSIONS: Circulating plasma levels of both soluble E-selectin and ICAM-1 were elevated in patients with variant angina, indicating an association of an inflammatory reaction with coronary spasm. Both soluble ICAM-1 and VCAM-1 appeared to be trapped in the coronary circulation at baseline and released into the coronary circulation following coronary spasm and reperfusion in the patients.

Acetylcholine↗
PubMed1997

Effect of a glutamine-enriched diet on small bowel allograft during immunosuppressive therapy.

The effect of an orally administered glutamine-enriched elemental diet was examined following orthotopic small bowel allotransplantation using Brown Norway rats as donors and Lewis rats as recipients. The recipients was treated with FK 506 and randomized to receive glutamine-free elemental enteral diet solution (glutamine-free group), glutamine-enriched elemental diet solution containing 7500 mg of glutamine per 100 g diet (glutamine-enriched group) or standard chow (chow group) ad libitum for 7 d. There were no histological changes due to resection. Weight loss in the glutamine-enriched group was significantly less than that of the chow group. Both plasma glutamine levels and the ratio of glutamine to total amino acids in the homogenate of the graft mucosa of the glutamine-enriched group were significantly higher than those of the glutamine-fee group. Villous height and crypt depth were significantly decreased in the glutamine-free group. The BrdU labeling index in the graft epithelium and alkaline phosphatase activity in the homogenate of the graft mucosa of the glutamine-enriched group were significantly higher than those of the glutamine-free group. Therefore, orally administered glutamine-enriched elemental diet appears to promote the regeneration and differentiation of the graft mucosa following small bowel allotransplantation.

Aging↗
PubMed1997

Imaging findings of lipomas in the orofacial region with CT, US, and MRI.

OBJECTIVE: The aim of this study was to document retrospectively the imaging findings of lipomas with the use of computed tomography, ultrasonography, and magnetic resonance imaging. STUDY DESIGN: Thirteen patients with 11 lipomas and 2 lipomatoses were evaluated. Eleven cases were examined by computed tomography, 9 by ultrasonography, and 3 by magnetic resonance imaging. RESULTS: Lipomas had a density ranging from -134 to -83 Hounsfield units, (mean-108) on the computed tomography images. The margins were ill defined in 9 of 10 cases. The superficial muscles were displaced externally in 8 cases and internally in 2 cases. With ultrasonography, 8 lesions were hypoechoic, and one was hyperechoic. All three lesions had a high signal intensity on both T1- and T2-weighted images. CONCLUSIONS: Lipomas had a specific range of computed tomography Hounsfield unit values and also displaced the surrounding soft tissue. Although some variation in the ultrasonographic appearance was observed, the lesions tended to be hypoechoic. These findings may be useful for diagnosing lipomas in the orofacial region.

Adolescent↗
PubMed1997

Computed tomography appearance of marked keratinization of metastatic cervical lymph nodes: a case report.

A case of squamous cell carcinoma of the tongue is reported with emphasis on an atypical finding of cervical lymph node metastasis visible on computed tomography. Multiple cervical lymph nodes revealed a high computed tomographic value of about 330 HU, lower than that of calcification. The lymph nodes revealed well-defined elliptical hyperechoic masses with an echogenic line and posterior shadow on ultrasonography. The appearance of a high density mass on computed tomography with a computed tomographic value lower than that of calcification may be a reliable finding of metastasis because it demonstrates the presence of marked keratinization produced by squamous cell carcinoma.

Calcinosis↗
PubMed1997

Application of fuzzy reasoning in an expert system for ultrasonography.

OBJECTIVES: To apply fuzzy reasoning in a computer-assisted diagnostic system for ultrasonography and to evaluate its clinical utility as a diagnostic aid for the unskilled clinician. METHODS: A computer-assisted diagnostic system for ultrasonography was constructed to differentiate metastatic from inflammatory lymph nodes. The pattern of a skilled clinician's considerations was simulated with the fuzzy expert system. Three fuzzy production rules were set up according to the diagnostic criteria for lymphadenopathy. Each rule was transformed into a membership function. The max-min composition method was used for inference and the centroid method for defuzzification. The system was tested with 20 clinicians who were one to three years after graduation and inexperienced in ultrasonography. Accuracy, sensitivity and specificity were evaluated. RESULTS: The average increase in accuracy was 8.5%, and the sensitivity and specificity 10.7% and 6.4% respectively. These scores were significant for accuracy (P = 0.005), sensitivity (P = 0.02) and specificity (P = 0.036). CONCLUSIONS: Application of fuzzy reasoning in an expert system for ultrasonography improves the diagnostic performance of inexperienced clinicians.

Clinical Competence↗
PubMed1997

Ultrasonographic texture characterization of salivary and neck masses using two-dimensional gray-scale clustering.

OBJECTIVES: To evaluate the clinical usefulness of texture analysis in ultrasonography (US) of head and neck masses. METHODS: Sixty-one cases with salivary or neck masses were examined by US with a linear 7.5MHz array. Images were digitized and quantitatively evaluated by two-dimensional gray-scale clustering using two texture indices, M and SD, as measures of coarseness and homogeneity respectively. RESULTS: Coarseness of Warthin's tumors was significantly higher than that of the other salivary tumors. Malignant lymphomas had finer texture values than other lymph node lesions. CONCLUSIONS: Quantitative texture analysis appears to be a useful complement in diagnostic US.

Diagnosis, Differential↗
PubMed1997

Tastes activate different second messengers in taste cells.

Taste signal transduction occurs in the microvillous membrane of taste cells. Previously, we hypothesized that c-GMP may mediate sweet taste transduction. Some data indicated that IP3 may have a role in vertebrate bitter taste transduction. Here we report that the different second messengers are activated by different tastes. We used techniques designed for radioimmunoassay measurement. The results indicate that sucrose triggers an increase in c-GMP concentration and quinine increases the IP3 concentration in mouse taste cells. These results support the sweet and bitter taste transduction hypotheses.

Animals↗
PubMed1997

Inhibitory actions of endothelial products on mechanical and calcium responses in aortic smooth muscle cells.

The effects of endothelial products on intracellular calcium ion concentrations ([Ca2+]i) were investigated in the guinea-pig aorta. The perfusate of bradykinin-stimulated cultured endothelial cells relaxed aortic rings by approximately 70%; it was reduced to approximately 50% by nitroarginine, to approximately 30% in high-K solution and remained unaltered by indomethacin. The perfusate elevated the cyclic GMP content in the muscle, which was inhibited by nitroarginine. In cultured, aortic muscle cells, bradykinin elevated [Ca2+]i with an initial transient and following sustained phase; the former was absent after treatment with cyclopiazonic acid while the latter was abolished in [Ca2+]o-free medium. The perfusate lowered aortic [Ca2+]i, and this action was weakened by nitroarginine and diminished in high-K solution. Therefore, the perfusate reduced aortic [Ca2+]i with and without an increase in cyclic GMP production. These actions were sensitive to nitroarginine and high-K, respectively, suggesting that the perfusate contained at least two relaxants, EDRF and EDHF, with both lowering [Ca2+]i in aortic muscle mainly by inhibiting Ca2+ influx.

Animals↗
PubMed1997

[Jejunal pouch interposition and distal gastrectomy].

We developed a new technique of reconstruction in Billroth 1 gastrectomy, jejunal pouch interposition (JPI). The interposed jejunal segment consists of a proximally double-plicated pouch and a distally isoperistaltic conduit. From 1987 to 1994, the JPI was performed on 102 patients with gastric carcinoma. The postoperative functional assay was carried out at least one year later after surgery. Sixty-five patients with the conventional Billroth 1 reconstruction (B-1) during the same period were employed as the control. Gastric emptying time estimated with scinti-scanning was significantly delayed in the JPI group compared with the B-1 group (p < 0.05). All individuals with JPI had meals three times a day whereas 13% of those with B-1 required those more than three times (p < 0.05). The incidence of dumping syndrome was significantly lower in the JPI group (6%) than the B-1 group (20%) (p < 0.05). The reflux of bile into the residual stomach was observed in the scintiscanning at 78% of patients with B-1 whereas 10% of those with JPI (p < 0.01). Endoscopy revealed that regurgitation gastritis was significantly decreased in the JPI group compared with that in the B-1 group (p < 0.01). These results suggest that the JPI prevents small stomach syndrome, dumping syndrome and alkaline reflux gastritis after the B-1 reconstruction.

Dumping Syndrome↗
PubMed1997

[Alteration of p15 and p16 gene in gastric cancer].

We analyzed p15 and p16 gene alterations in gastric cancer. Only MKN45 showed both homozygous deletions but other cell lines and all of tumor specimens did not show any alterations. Using RT-PCR analysis, decreased or no expression of the p16 gene was found in 1 of 7 cell lines (except MKN45) (14.2%) and in 8 of 20 tumors (40%), whereas no abnormalities of p15 gene expression were found. These results suggest that the p16 gene may correlate with tumorigenesis and tumor expansion due to decrease or loss of gene products in gastric cancer.

Adenocarcinoma↗
PubMed1996

Suppression of prostaglandin E receptor signaling by the variant form of EP1 subtype.

A cDNA clone of prostaglandin (PG) E receptor EP1 subtype (rEP1) was isolated from a rat uterus cDNA library. It encodes 405 amino acid residues with seven transmembrane-spanning domains and couples to Ca2+ mobilization. In addition, three cDNA clones encoding a variant form of rEP1 were isolated. The open reading frame can code a 366-amino acid protein carrying a specific change of 49 amino acids from the middle of transmembrane segment VI to COOH terminus; it possesses a transmembrane segment VII-like structure lacking an intracellular COOH-terminal tail. Southern blot analysis of rat genomic DNA and genomic polymerase chain reaction demonstrated that these cDNAs were derived from a single copy gene. Northern blot analysis and ribonuclease protection assay revealed that both rEP1 and rEP1-variant receptor mRNAs were highly expressed in the kidney. Immunoblot with an antibody directed toward the specific region of rEP1-variant receptor showed that rEP1-variant receptor protein was expressed in the membrane of the kidney and Chinese hamster ovary (CHO) cells transfected with rEP1-variant cDNA. Thus, the rEP1-variant receptor is translated from mRNA which is not spliced at nucleotide position 952 in the segment VI transmembrane region. rEP1-variant receptor retained the ligand binding activity with affinity and specificity similar to rEP1 receptor, but lost the coupling of signal transduction systems by itself. However, when rEP1-variant receptor was stably co-expressed with rEP1 receptor in CHO cells, the Ca2+ mobilization mediated by EP1 receptor was significantly suppressed. Furthermore, when rEP1-variant receptor was expressed in CHO cells, cAMP formation by activation of endogenous EP4 receptor was strongly blocked. These results suggest that the rEP1-variant receptor may affect the efficiency of signal coupling of PGE receptors and attenuate the action of PGE2 on tissues.

Amino Acid Sequence↗
PubMed1996

Apoptosis of mouse naive T cells induced by recombinant soluble Fas ligand and activation-induced resistance to Fas ligand.

We have investigated the susceptibility of mouse T cells at various maturation and activation stages to recombinant soluble mouse Fas ligand (termed WX1). CD4+CD8+ thymocytes were preferentially killed by WX1, although CD4+CD8- and CD4-CD8+ thymocytes were also killed at higher concentrations of WX1. The majority of CD4-CD8- thymocytes were resistant to the same doses of WX1. Naive peripheral T cells were also killed by WX1 at concentrations similar to those for single-positive thymocytes. Activation-induced cell death of previously activated T cells is known to be mediated by Fas and Fas ligand. However, the activation of naive splenic T cells by mAbs against CD3/TCR complex rather induced resistance against WX1. This resistance was induced in activated T cells but not in bystander T cells. These mechanisms seem to explain why activated T cells are not immediately killed and why bystander T cells are not activated in an Ag-nonspecific manner.

Animals↗