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Biomedical subjects

T Miwa

Publications and source records attributed to T Miwa.

At least 325 records · Page 18Linked to original sources
PubMed1984

Isolation of parietal cells from guinea-pig gastric mucosa by a Percoll density gradient.

Isolation of parietal cells from guinea-pig gastric mucosa was performed by density gradient centrifugation using percoll, a new gradient medium composed of colloidal silica coated with polyvinylpyrolidone. The gastric mucosa of the oxyntic gland area was exfoliated, minced and digested with 2.0 mg/ml of dispase and 0.1 mg/ml of collagenase. Dispersed mucosal cells were applied to the percoll density gradient. Parietal cells were fractionated in the layer between 1.04 and 1.06 g/ml in density with purity 80 approximately 90%. For identification of parietal cells staining with tetranitrobluetetrazolium and electron microscopy were used in addition to common staining. The viability of the cells was over 95% assessed by trypan-blue exclusion. The parietal cells obtained responded actively to histamine stimulation when 14C-aminopyrine uptake was used as an functional index. In conclusion, percoll density gradient medium is suitable for yielding isolated parietal cells with both high purity and high viability.

Aminopyrine↗
PubMed1984

Inhibition of gastric secretion by a new H2-antagonist, YM-11170 in healthy subjects.

Oral administration of YM-11170 (5-20 mg) inhibited both basal and tetragastrin-induced gastric secretion of acid and pepsin in healthy volunteers. YM-11170 was at least 20 times more potent than cimetidine in inhibiting stimulated acid secretion. The area under the plasma concentration of YM-11170 vs time curve correlated positively to both dose and percent inhibition of acid output in response to tetragastrin. YM-11170 significantly inhibited basal and stimulated acid secretion even 10 h after a 20-mg dose. A plasma level of YM-11170 required for 50% inhibition of stimulated acid secretion was found to be 13 ng/ml. These results indicate that YM-11170 is a very potent inhibitor of gastric acid secretion and that twice daily medication of 20 mg YM-11170 is recommendable for further antisecretory studies with ulcer patients.

Administration, Oral↗
PubMed1983

Lambda phage DNA sequences affecting the packaging process.

Our previous work identified a minimal region of bacteriophage lambda DNA that is necessary for packaging into phage particles. It consists of 40 bp of the right arm and 45 bp of the left arm [Miwa and Matsubara, Gene 20 (1982)267-279]. A part of this region, 22 bp of the right arm and 38 bp of the left arm, is sufficient for cutting at cos lambda (the minimal sequence for cos lambda cutting). An 84-bp region to its right contains a binding site for lambda terminase, a complex of Nu1 and A gene products. This second region, which we called the enhancing region for packaging, stimulates cutting at cos lambda as well as packaging. This region is not active if it is physically separated from the minimal packaging region. The enhancing region has 15-bp inverted repeats. These sequences are conserved in the corresponding region of bacteriophage phi 80, which has the same packaging specificity as lambda.

Bacteriophage lambda↗
PubMed1983

Instability of bacteriophage lambda initiator O and P proteins in DNA replication.

Lambda dv plasmids having an amber mutation in an initiator gene, O or P, were constructed from mutant lambda phages by recombinant DNA techniques and several properties of such derivatives were investigated. These plasmids are perpetuated in suppressor-plus (amber-permissive) cells, but not in non-suppressor cells. The plasmid copy number in the suppressor-plus cells was low as compared to that of the plasmid without the amber mutation. In cells carrying a thermosensitive suppressor 2, raising the temperature is expected to block new production of amber proteins, but should not affect conservation of the protein made prior to heating. It was observed, however, that replication of the plasmids carrying an amber mutation in the O or P gene was abolished soon after raising the temperature, suggesting that neither of the initiator proteins can continue functioning unless replenished. Pulse-chase experiments demonstrated that O protein decays with a half-life of 8 min. Several lines of evidence suggest that this degradation occurs independently of the protein function. On the other hand, P protein was not degraded under the same experimental conditions. These observations are discussed in connection with functional instability of the initiator molecules. It appears that they do not work catalytically.

Bacteriophage lambda↗
PubMed1983

Formation of oligomeric structures from plasmid DNA carrying cos lambda that is packaged into bacteriophage lambda heads.

Plasmids that carry cos lambda, the region necessary for lambda phage packaging and that are as small as four kilobases in size can be packaged into lambda phage heads in head-to-tail tandem oligomeric structures. Multimeric oligomers as large as undecamers have been detected. Oligomer formation depends upon the products of red and gam of lambda, and the general recombination occurs between different plasmids that share homologous DNA regions. The packaging efficiency of plasmids depends on its copy number in cells and its genome size. Upon injection into a cell, the DNA establishes itself as a plasmid in a tandem structure. When such a plasmid in a high oligomeric structure is used as the source of packaging DNA, the packaging efficiency of the plasmids is elevated. The oligomers are stable in recA cells, whereas they drift toward lower oligomers in recA+ cells.

Bacteriophage lambda↗
PubMed1983

Flow-dependent water permeability of the rabbit descending limb of Henle's loop.

Because completely opposite results have been reported on the water permeability of the rabbit descending limbs of Henle's loop (DLH), we rigorously examined water permeability of the upper portion of the descending limb of the rabbit long-looped nephron. Even when the double-cannulation method was used in an attempt to reduce the resistance of tubular outflow, the collected fluid-to-perfusate inulin ratio was equal to or very close to the bathing fluid-to-perfusate osmolality ratio, indicating that osmotic equilibration occurred along the tubule by absorption of water. When perfusion rates were controlled by varying the height of the fluid reservoir connected to the perfusion pipette, osmotic (Pf) as well as diffusional (Pdw) water permeability was shown to be correlated with perfusion rate and/or perfusion pressure. Pf and Pdw at zero perfusion rate as determined from the values of the intercept of regression lines were 253 X 10(-3) and 4.54 X 10(-3) cm X s-1, respectively. The maximal values for Pf and Pdw were 737-1,098 X 10(-3) and 18.3 X 10(-3) cm X s-1, respectively. By changing the resistance to perfusion at the tubular outflow, it was shown that changes in Pf paralleled changes in perfusion rate rather than changes in perfusion pressure. Under stop-flow conditions the luminal fluid volume rapidly decreased after the osmolality of the bathing fluid was increased, suggesting that the segment is highly permeable to water even at zero flow rate. Reflection coefficients for urea and NaCl were 1.01 and 0.82, respectively. These data support the view that this segment is highly permeable to water and that increases in osmolality along the DLH in vivo may be accounted for mainly by abstraction of water rather than addition of solutes.

Animals↗
PubMed1983

Decomposition of hydroperoxides derived from microsomes or lipoprotein by glutathione peroxidase and glutathione S-transferase.

Protective effects of glutathione peroxidase, glutathione S-transferase purified from human liver and superoxide dismutase against lipid peroxidation were investigated. In the presence of glutathione, lipid hydroperoxides found in microsomal membrane were decomposed by glutathione peroxidase and cationic glutathione S-transferase, but anionic glutathione S-transferase had no effect on them. Superoxide dismutase exhibited antioxidation effect by preventing accumulation of lipid hydroperoxides. Serum lipid hydroperoxides existing in low density lipoprotein fraction were also decomposed by glutathione peroxidase and cationic glutathione S-transferase. These findings suggest that the hydroperoxide level, which has high toxicity, could be controlled by these glutathione-dependent glutathione peroxidase and cationic glutathione S-transferase.

Animals↗
PubMed1983

Method for detection of antibody against low molecular weight antigen (hapten)--production and detection of antibody against histamine H2 receptor of antibody against histamine H2 receptor antagonist "Famotidine".

Antibodies against histamine H2-receptor antagonist "Famotidine (FAMO)", molecular weight 337, chemical name; N-sulfamoyl-3-(2-guanidinothiazol-4-ylmethylthio) propionamide, were produced by subcutaneously injecting rabbits with an albumin and FAMO conjugate covalently bound with 1-ethyl-3-(3-dimethyl-amino-propyl) carbodiimide (ECDI). Two new detection systems for antibody titration were developed and employed. In one method, the antigen FAMO was tagged to sheep red blood cells (SRBC) and analysed qualitatively by a fluorescence activated cell sorter (FACS) using a second fluorescence isothiocyanate (FITC) labeled antibody. In the other method, CH-Sepharose beads were employed in place of SRBC and Horse Radish Peroxidase (HRP) was labeled to the second antibody instead of FITC used in the former method. HRP of the immune complex was colorimetrically measured with DAB-H2O2 to analyse the fine antibody titer. These high sensitive detection methods revealed the existence of IgG type of FAMO antibody. The detection sensitive detection methods revealed the existence of IgG type of FAMO antibody. The detection sensitivity was approximately 50 to 100 times higher in the later method with HRP than in the former. Furthermore these two methods could be deemed to be a good model system for a receptor assay.

Animals↗
PubMed1983

Bifid tail of the pancreas: a case presenting as a gastric submucosal tumor.

A 49-yr-old male was admitted to our hospital because of epigastric discomfort and a suspected tumor of the stomach on barium meal examination at the Center for Automated Multiphasic Health Test and Services. The tumor shadow of the stomach was initially considered as the "type II" gastric carcinoma according to the Borrmann's classification. Multiple endoscopical and electrocautery cutting biopsies revealed that the tumor occurred in the submucosal layer and was composed of normal pancreatic tissue. A computed tomogram showed a large mass on the pancreatic body which was adjacent to gastric wall. Selective angiography of the celiac trunk revealed that the gastric submucosal lesion was supplied by the transverse pancreatic artery. Endoscopic retrograde pancreatography showed that Wirsung's duct had a divergence in the body of the pancreas and one of the branched ducts headed for the posterior wall of the gastric body. On the basis of these results, a diagnosis was made of the rare pancreatic anomaly, "bifid tail of the pancreas." One of the tails formed the gastric submucosal tumor. This report emphasizes the potential diagnostic value of combined study of endoscopic retrograde pancreatography and computed tomography in determining the presence of pancreatic anomaly.

Cholangiopancreatography, Endoscopic Retrograde↗