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Biomedical subjects

K Matsuda

Publications and source records attributed to K Matsuda.

At least 487 records · Page 27Linked to original sources
PubMed1991

Characterization of cholecystokinin receptors on guinea pig gastric chief cell membranes.

The binding of cholecystokinin (CCK) to its receptors on guinea pig gastric chief cell membranes were characterized by the use of 125I-CCK-octapeptide (CCK8). At 30 degrees C optimal binding was obtained at acidic pH in the presence of Mg2+, while Na+ reduced the binding. In contrast to reports on pancreatic and brain CCK receptors, scatchard analysis of CCK binding to chief cell membranes revealed two classes of binding sites. Whereas, in the presence of a non-hydrolyzable GTP analog, GTP gamma S, only a low affinity site of CCK binding was observed. Chief cell receptors recognized CCK analogs, with an order of potency of: CCK8 greater than gastrin-I greater than CCK4. Although all CCK receptor antagonists tested (dibutyryl cyclic GMP, L-364718 and CR1409) inhibited labeled CCK binding to chief cell membranes, the relative potencies of these antagonists in terms of inhibiting labeled CCK binding were different from those observed in either pancreatic membranes or brain membranes. The results indicate, therefore, that on gastric chief cell membranes there exist specific CCK receptors, which are coupled to G protein. Furthermore, chief cell CCK receptors may be distinct from pancreatic or brain type CCK receptors.

Animals↗
PubMed1991

The inhibitory effect of anti-tumor drugs on phosphatidylcholine synthesis and its reversal by geranylgeranylacetone in the isolated guinea pig gastric glands.

To clarify the mechanism by which the administration of anti-tumor drugs, antibiotics or hypoglycemic agents causes gastric mucosal injury, the effects of these drugs on phosphatidylcholine synthesis in isolated guinea pig gastric glands were examined in vitro. Anti-tumor drugs such as tegafur, cyclophosphamide, and mitomycin C decreased [3H]choline incorporation into phosphatidylcholine. Furthermore, tegafur at 0.4 mg/ml decreased [3H]choline incorporation in the glands that had been pulsed with [3H]choline incorporation, suggesting that tegafur exerts its effect by inhibiting late step of phosphatidylcholine synthesis in the stomach. On the other hand, cefaclor and glibenclamide had no effect on [3H]choline incorporation. Geranylgeranylacetone, an anti-ulcer drug partially restored tegafur-induced reduction of [3H]choline incorporation into phosphatidylcholine. These results suggest that the anti-tumor drug-induced gastric mucosal injury may be due to drug-induced decrease in phosphatidylcholine synthesis, which the restoration of phosphatidylcholine synthesis by geranylgeranylacetone may explain its anti-ulcer action on drug-induced gastric mucosal lesions in vivo.

Animals↗
PubMed1991

Ethanol stimulates pepsinogen release by opening a Ca2+ channel of guinea pig gastric chief cells.

To better understand the mechanism by which ethanol causes gastric mucosal injury, the effects of ethanol on isolated guinea pig gastric chief cells were investigated in vitro. Ethanol at 300-900 mmol/L dose-dependently stimulated an increase in pepsinogen release without affecting chief cells' viability. Ethanol stimulated an increase in initial Ca2+ influx rate and intracellular Ca2+ concentration at the same concentrations as it stimulated pepsinogen release, whereas it did not stimulate cyclic adenosine monophosphate accumulation. Pepsinogen release stimulated by 900 mmol/L ethanol was almost equal to that stimulated by 10(-8) mol/L COOH terminal octapeptide of cholecystokinin. Ethanol did not stimulate an increase in the accumulation of inositol trisphosphates and tetrakisphosphates in [3H]inositol-labeled chief cells, whereas cholecystokinin octapeptide caused a significant increase in inositol trisphosphates and tetrakisphosphates. Ethanol-stimulated pepsinogen release and increases in the initial Ca2+ influx rate and intracellular Ca2+ concentration were inhibited by 0.5 mmol/L La3+ or 1 mmol/L ethylene glycol tetraacetic acid but were not inhibited by nifedipine or verapamil. These results suggest that the effect of ethanol on pepsinogen release from the gastric chief cells may be due to its opening of a Ca2+ channel that is sensitive to La3+ and that the pepsinogen releasing action of ethanol may be one of factors for ethanol-induced gastric mucosal injury.

Animals↗
PubMed1991

Involvement of prolactin in the regulation of plasma calcium levels in the newt, Cynops pyrrhogaster.

In the newt, Cynops pyrrhogaster, parathyroidectomy (PTX) brought about a marked decrease in the concentration of plasma calcium. The animals recovered from the hypocalcemia by 15 days after the operation if the pituitary gland was left intact. After PTX, no significant changes in the plasma sodium concentration were observed. Experiments were then conducted to obtain direct evidence that endogenous prolactin (PRL) is involved in this recovery process. Recovery of the calcium level after PTX was blocked by administration of an antiserum raised against newt PRL. In newts deprived of both the pituitary and parathyroid glands, no recovery from hypocalcemia was observed. Administration of newt or ovine PRL to parathyroidectomized-hypophysectomized newts significantly elevated the blood calcium level. After PTX, the concentration of immunoassayable PRL in the blood rose to 10 times the value in sham-operated animals. These results indicate the involvement of PRL in calcium homeostasis in newts with a shortage of parathormone.

Animals↗
PubMed1991

Amphibian prolactins: activity in the eft skin transepithelial potential bioassay.

The effects of purified prolactins isolated from frogs (fPRL; Rana catesbeiana) and newts (nPRL; Cynops pyrrhogaster) were compared with those of ovine prolactin (oPRL) and thyrotropin releasing hormone (TRH) in the eft (Notophthalmus viridescens) skin transepithelial potential (TEP) bioassay. At total doses as low as 0.4 micrograms/animal, both fPRL and nPRL were as effective as oPRL in reducing eft skin TEP. By contrast, TRH at total doses as high as 400 micrograms/animal was ineffective in altering eft skin TEP. These data provide the first direct evidence that amphibian PRLs can exert significant physiological control over salamandrid integumental sodium transport.

Animals↗
PubMed1991

Apolipoprotein B is a major perforin inhibitor protein in human serum.

We purified the high-molecular-weight perforin inhibitor protein from normal human serum using DEAE-cellulose, HPLC-gel filtration and hydroxylapatite chromatography. This protein was shown to be identical to the serum apolipoprotein B-100 in terms of amino acid composition and the sequence of the digested peptides. This inhibitor protein not only inhibits the membrane binding activity of perforin but also the pore insertion activity of membrane-bound perforin.

Amino Acid Sequence↗
PubMed1991

In-vitro activity of imipenem combined with beta-lactam antibiotics for methicillin-resistant Staphylococcus aureus.

The in-vitro activity of imipenem combined with beta-lactam antibiotics was studied for 25 strains of methicillin and imipenem-resistant Staphylococcus aureus (MRSA) in comparison with that of fosfomycin combined with cefmetazole. Using the chequerboard agar dilution method, strong synergy was seen for all strains for imipenem with cefoperazone, cefotiam, cefpiramide or piperacillin. All fractional inhibitory concentration indices (FIC indices) of these combinations were less than or equal to 0.12. For the combination of imipenem with cefotiam the synergy was found to be bactericidal, but was not affected by the temperature of incubation, the concentration of sodium chloride in the medium or beta-lactamase production. However, for the combination of fosfomycin with cefmetazole only 44% of the strains with a mean FIC index of 0.55, showed synergy. The remaining 56% of strains showed either partial synergy (44%) or additive activity (12%). The combinations of imipenem with the beta-lactam antibiotics were more effective than that of fosfomycin with cefmetazole.

Anti-Bacterial Agents↗
PubMed1991

Temperature-dependent water and ion transport properties of barley and sorghum roots : I. Relationship to leaf growth.

Root temperature strongly affects shoot growth, possibly via "nonhydraulic messengers" from root to shoot. In short-term studies with barley (Hordeum vulgare L.) and sorghum (Sorghum bicolor L.) seedlings, the optimum root temperatures for leaf expansion were 25 degrees and 35 degrees C, respectively. Hydraulic conductance (L(p)) of both intact plants and detached exuding roots of barley increased with increasing root temperature to a high value at 25 degrees C, remaining high with further warming. In sorghum, the L(p) of intact plants and of detached roots peaked at 35 degrees C. In both species, root temperature did not affect water potentials of the expanded leaf blade or the growing region despite marked changes in L(p). Extreme temperatures greatly decreased ion flux, particularly K(+) and NO(3) (-), to the xylem of detached roots of both species. Removing external K(+) did not alter short-term K(+) flux to the xylem in sorghum but strongly inhibited flux at high temperature in barley, indicating differences in the sites of temperature effects. Leaf growth responses to root temperature, although apparently "uncoupled" from water transport properties, were correlated with ion fluxes. Studies of putative root messengers must take into account the possible role of ions.

Journal Article↗
PubMed1991

Preferential hydrolysis of cis configuration compounds at the 3,4 position of monobactams by beta-lactamase from Morganella morganii.

Carumonam and BO-1166 (cis configuration) were inactivated by beta-lactamase of Morganella morganii more rapidly than were aztreonam and BO-1165 (trans configuration), as demonstrated by spectrophotometric analysis and microbiological assay. An active enzyme was recovered more rapidly from the inactivated enzyme-monobactam complex derived from the cis form of monobactams than from the complex derived from the trans form of monobactams. This result suggests that the configuration at the 3,4 position on the azetidinone ring of monobactams, together with the chemical structure of the side chains attached to the azetidinone ring, may play an important role in the stability of monobactams to the beta-lactamase of M. morganii.

Aztreonam↗
PubMed1991

Absorption, biliary excretion, and metabolism of a new cholelitholytic agent, ursodeoxycholyl N-carboxymethylglycine and its esters in rats.

Intestinal absorption, biliary excretion and metabolism of a calcium gallstone dissolving agent, [11,12-3H]ursodeoxycholyl-N-carboxymethylglycine (UDC-CMG) and its monoethyl, diethyl and dipivaloyloxyethyl esters (UDC-CMG-Et, UDC-CMG-Et2 and UDC-CMG-PV2) were studied in bile duct cannulated rats. Biliary recovery of [3H]-labeled UDC-CMG, UDC-CMG-Et and UDC-CMG-Et2 after intraduodenal administration were 65%, 80%, 98%, respectively. Radio-thin layer chromatography analysis of the bile revealed that UDC-CMG didn't undergo any biotransformation during administration and excretion. About 80% and 20% of radioactivity recovered in the bile was identified as UDC-CMG-Et and UDC-CMG, respectively, after intraduodenal administrations of [3H]UDC-CMG-Et2 and [3H]UDC-CMG-Et. The administered intact UDC-CMG-Et2 was not found in the bile. Intraduodenally administered [3H]UDC-CMG-PV2 was rapidly recovered in the bile. The total recovery rate was 78% within a 24 h period. More than 80% of the radioactivity recovered in the bile was found as UDC-CMG. Lesser amounts of the monopivaloyloxyethyl ester of UDC-CMG were also found, but intact UDC-CMG-PV2 was not detected in the bile as in the case of UDC-CMG-Et2. Among the esters of UDC-CMG investigated in the present studies, only UDC-CMG-PV2 was excreted in the bile mainly as the perhydrolyzed form, UDC-CMG. These results suggest the usefulness of UDC-CMG-PV2 as the pro-drug in calcium gallstone dissolution therapy.

Animals↗
PubMed1991

A case of congenital left ventricular diverticulum with pulmonary stenosis and its scintigraphic characteristics.

We encountered a 31-year-old female patient with mild valvular pulmonary stenosis who had no abnormality in the electrocardiogram but pulmonary dilatation in the chest radiograph. Two-dimensional echocardiography and magnetic resonance imaging demonstrated two small protrusions at the interventricular septum indicating diverticula. Large perfusion defects were observed at the anterior wall in the thallium-201 myocardial tomograms. Short axial and vertical long axial images by ECG-gated blood pool tomography revealed an out-pouching best seen during diastole and a good contraction during systole in the corresponding areas. These findings suggested the presence of thin but normal myocardium in the anterior wall, i.e. a muscular type of left ventricular diverticulum. The presence of the muscular type of left ventricular diverticulum at the anterior and septal walls was confirmed by contrast left ventriculography. A congenital diverticulum at the anterior and septal walls with pulmonary stenosis is very rare. Furthermore, its scintigraphic images were quite characteristic and useful for its diagnosis.

Adult↗
PubMed1991

[Basal studies on the model of circular excisional wounds made on the dorsal skin of rats treated with hydrocortisone].

This study was performed to establish a circular excisional wound model treated with hydrocortisone (HC-P) and to estimate the following parameters in this model: wound area, hydroxyproline (Hyp) content, histological characteristics and microscopical measurements of histological sections. HC-P inhibited the reduction of wound area, the increase in Hyp content and proliferation of granulation tissue in a dose-dependent manner. The application of ZnO ointment significantly accelerated the reduction of wound area and the increased Hyp content in rats treated with HC-P. From these results, we concluded that this experimental model is useful for the objective evaluation of the efficacy of drugs that promote wound healing.

Animals↗
PubMed1991

Sugar-specific inhibitory effects of wheat germ agglutinin and phytohemagglutinin-E4 on histamine release induced by basic secretagogues from rat peritoneal mast cells and their possible action sites.

The histamine release induced by compound 48/80, bradykinin or polyethylenimine with a molecular weight of 600 (PEI6) was inhibited by wheat germ agglutinin (WGA) and phytohemagglutinin E-subunits (PHA-E4), and the inhibition was specifically reversed by N-acetyl glucosamine and N-acetyl galactosamine, respectively. Concanavalin A (Con A) and phytohemagglutinin L-subunits (PHA-L4) did not inhibit the histamine release induced by compound 48/80, bradykinin or PEI6. The histamine release induced by substance P was also inhibited sugar-specifically by WGA and PHA-E4. The binding sites for compound 48/80, bradykinin, PEI6 and substance P, therefore, seemed to especially overlap each other. These binding sites were found to be glycoproteins having affinities to WGA and PHA-E4, but not to Con A and PHA-L4. The binding of WGA and PHA-E4 to the glycoproteins resulted in inhibition of the interaction between the basic secretagogues including bradykinin and substance P and their binding sites on the mast cells. The bindings of five lectins to mast cell glycoproteins were examined by lectin-blotting. Several glycoproteins, which had specific affinities to WGA and PHA-E4, but not to Con A and PHA-L4 were detected. We assumed that the binding sites for basic secretagogues which are coupled with histamine-releasing mechanisms exist among these glycoproteins. A 41-kDa protein (alpha-subunit of pertussis toxin-sensitive G protein) was not detected by WGA, suggesting that the binding sites for the basic secretagogues were not G proteins.

Acetylgalactosamine↗