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Biomedical subjects

K Kobashi

Publications and source records attributed to K Kobashi.

At least 163 records · Page 9Linked to original sources
PubMed1983

Effect of Clostridium butyricum on the formation and dissolution of gallstones in experimental cholesterol cholelithiasis.

The effect of oral administration of Clostridium butyricum Miyairi on the formation and dissolution of gallstones was examined in a mouse model of cholesterol cholelithiasis, in comparison with that of chenodeoxycholic acid (CDCA). A diet containing cholesterol and sodium cholate was used as a lithogenic diet. The feeding of the lithogenic diet containing 1.0 X 10(8) cells of this bacterium per g for five weeks prevented the formation of gallstones, resulted in lower values of the gallstone index, incidence and cholesterol content of gallstones than those of untreated group by 46, 43 and 46%, in order. Furthermore, after mice were maintained on the lithogenic diet for five weeks, subsequent bacterial treatment exhibited a marked gallstone dissolution effect. The feeding of 10(8) cells/g was effective for the prevention of gallstone formation and dissolution of gallstones, but that of 10(6) cells/g was not significantly effective. The gallstone index of the bacterium-treated group was lower than that of CDCA-treated group during the period of experiment, but there was no difference in the cholesterol content of gallstones between these two groups, which suggests a different mechanism of action of the bacterium from that of CDCA.

Animals↗
PubMed1983

Effect of fructose 1,6-bisphosphate on the activity of liver pyruvate kinase after limited proteolysis with cathepsin B.

Treatment of rat liver-type pyruvate kinase with rabbit liver cathepsin B at pH 7.0 caused loss of activity in the standard assay with 0.6 mM of phosphoenolpyruvate. The modified enzyme exhibited about 10% of the original activity when assayed with 2.0 mM of the substrate. No detectable change in the subunit molecular weight of the enzyme occurred during inactivation. On addition of 4 microM fructose 1,6-bisphosphate the activity of the treated enzyme was restored to that of the original enzyme. Limited proteolysis of the enzyme by cathepsin B appears to enhance the requirement for the positive effector, fructose 1,6-bisphosphate.

Animals↗
PubMed1983

The role of protease in streptolysin S formation.

Production of streptolysin S by streptococci was found to be inhibited by treatment with protease inhibitors, tosylphenylalanine chloromethyl ketone (TPCK), tosyllysine chloromethyl ketone (TLCK), or phenylmethylsulfonyl fluoride (PMSF), even in the presence of the inducer oligonucleotides. Other protease inhibitors, antipain, leupeptin, or pepstatin were found to have little or no effect. Trypsin reversed the effect of TPCK or TLCK. The reversal was dependent upon the amount of added trypsin and the incubation time at 37 degrees C, suggesting that a protease activity was involved in the hemolysin formation. The effect of trypsin was not observed if chloramphenicol was also added, suggesting that a precursor of streptolysin S was processed as it was synthesized and released into medium as the active hemolysin, by the concerted action of a protease and inducer oligonucleotides. Experiments with the subcellular fractions of streptococci indicated that the streptolysin precursor was localized in the insoluble fraction and the "processing" protease in the supernatant fraction.

Cell-Free System↗
PubMed1983

Photo-oxidation of Jack bean urease in the presence of methylene blue.

Photo-oxidation of Jack bean urease was performed in the presence of a low concentration of methylene blue, which led to the complete loss of the enzymatic activity. The inactivation was more remarkable in an alkaline region than in an acidic region and prevented by the addition of histidine or methionine. Amino acid analysis of the oxidized enzyme revealed that the number of histidine residues had decreased to 73% that of the native enzyme, but the numbers of other amino acid residues were not significantly affected. Benzohydroxamic acid, a specific urease inhibitor, protected the active site of the enzyme against photo-oxidation. On the other hand, oxidation of the enzyme decreased its binding ability with caprylo- and benzohydroxamic acid to one-third. These results suggest that histidine residues are modified by photo-oxidation and are essential to both the enzymatic activity and the binding ability with hydroxamic acid.

Fabaceae↗
PubMed1983

Cholesterol-lowering effect of Clostridium butyricum in cholesterol-fed rats.

We examined the effects of oral administration of Clostridium butyricum miyairi on the catabolism and excretion of cholesterol in normal rats by using 14C-labeled cholesterol, and on plasma cholesterol levels in the rats and mice fed a high cholesterol diet. This bacterial treatment (about 10(7) cells/day) accelerated the cleavage of cholesterol side chain in normal rats. Plasma cholesterol levels of rats fed the high cholesterol diet with the bacterium (about 10(9) cells/day) were significantly lower than those of the control rats, and the effect was confirmed by exchanging the diets of both groups. However, plasma cholesterol levels of mice were not affected by this bacterial treatment.

Administration, Oral↗
PubMed1983

Study on hydroxamic acids and their urease inhibitory potency by quantum chemistry calculation.

The electronic structures of 34 hydroxamic acids [R-(CONHCH2(n-CONHOH, R = aromatic or aliphatic, n = 1 or 0] were calculated by the INDO method and their urease inhibitory potencies were discussed in terms of the calculated electronic parameters and molar refraction. The charge distribution of -CONHOH residue which has been expected as a functional group for inhibition slightly be affected by the change of R - moiety and by the presence or absence of the -CONHCH2- residue. The best improved regression equation indicated that the inhibitory potency of hydroxamic acids was parabolically varied with the molar refraction and that the increase of the inhibitory potency by the presence of -CONHCH2- residue was explained by the variation of the charge density of a carbon atom directly bonding the -CONHOH group.

Chemical Phenomena↗
PubMed1983

[Prevention of infected urinary stones by urease inhibitor. IV. Treatment of infection stones in rats by a new hydroxamic acid and cefalexin].

We investigated the combined effectiveness of a new urease inhibitor, N-( pivaroyl ) glycinohydroxamic acid, with Cefalexin in the treatment of infection stones in rats. Combination therapy with the hydroxamic acid and Cefalexin inhibited bladder stone formation, and dissolved the stone dose dependently, while separate therapy was not significantly effective against stone formation or bacterial growth. This compound may become a useful medicine for the treatment of infection stones.

Animals↗
PubMed1983

[Eosinophilic cystitis: a report of 2 cases].

Two patients with eosinophilic cystitis are presented in this report. The first case was a 39-year-old man who was admitted to our clinic with complaints of pollakisuria, pain on urination and hematuria for a month, which had not been relieved by antibiotic therapy. He had both a family and a personal past history of allergy. Excretory urograms showed a mild bilateral hydroureter and small bladder with irregular filling defects. Cystoscopic examination revealed velvety, ulcerated areas in the bladder mucosa, and we diagnosed these changes as eosinophilic cystitis after bladder biopsy. Steroid and antihistaminic therapy improved these symptoms. The second case was a 67-year-old woman who visited our clinic complaining chiefly of hematuria for 2 months. There was no predisposition to allergy, but she had a past history of uterine cancer which had been treated with irradiation. Cystoscopic examination disclosed a large amount of intravesical coagula, and erythematous and edematous areas with petechiae of the bladder mucosa. Bladder biopsy revealed hemangioma and eosinophilic cystitis. There was no recurrence of cystitis after the removal of the coagula without any other treatment.

Adult↗
PubMed1982

Treatment of infected urinary stones in rats by a new hydroxamic acid, "N-(pivaloyl)glycinohydroxamic acid.

The effectiveness of a new urease inhibitor, N-(pivaloyl)glycinohydroxamic acid, in the treatment of infected urinary stones was investigated. The hydroxamic acid markedly inhibited and alkalinisation of urine and stone formation when it was administered orally to rats with urinary tract infection caused by Proteus mirabilis; its inhibitory effect was potentiated by concomitant treatment with Cephalexin. This compound may become a useful medicine for the treatment of struvite stones.

Animals↗
PubMed1982

High-molecular-weight hemolysin of Clostridium tetani.

Clostridium tetani excretes hemolysins of two size classes, a high-molecular-weight hemolysin (HMH), which was eluted near void volume of a Sepharose 6B column, and conventional tetanolysin (molecular weight, approximately 50,000). The total hemolysin activity in the culture supernatant increased sharply with growth of bacteria and remained at a high level during autolysis. The content of HMH, however, decreased from 41% at 4 h of culture to 0.4% at the early stage of autolysis. The cell bodies also exhibited hemolytic activity, 70% of which could be solubilized and separated into HMH and the 50,000 Mr tetanolysin as extracellular hemolysins. The activity ratio of HMH to the total solubilized hemolysins was 0.45, on the average, at 6 h of culture but was 0.23 at the middle of logarithmic growth. Partially purified HMH from both sources appeared as broken pieces of cytoplasmic membranes under an electron microscope. The ratio of proteins to phospholipids in HMH was found to 3.26, a value similar to that in cell membrane. The total cell hemolytic activity decreased by 90 or 75% upon addition of chloramphenicol or anti-tetanolysin serum, respectively, into a 6-h-old culture of bacteria. It is suggested that HMH is a complex of tetanolysin with a membrane fragment and releases the conventional tetanolysin during bacterial culture.

Bacterial Toxins↗
PubMed1981

Two esterases released from Mycobacterium smegmatis from the hydrolysis of long chain acyl-CoAs and Tween.

An esterase activity hydrolyzing palmitoyl-CoA was released into the culture medium from Mycobacterium smegmatis. Although another esterase activity hydrolyzing Tween 20 (polyoxyethylene sorbitan monolaurate) was also found in the culture medium, the bulk of the esterase activity was retained in the cells. However, treatment of early-log phase cells with lysozyme to prepare ghosts released 80% of the Tween 20 hydrolyzing activity, indicating the localization of the esterase in the periplasmic space or the cell envelope fraction. The presence of two different esterases hydrolyzing palmitoyl-CoA and Tween 20, suggested by the above results, was confirmed by the separation of these esterases on phenyl-Sepharose column chromatography. Palmitoyl-CoA hydrolase (thioesterase) was purified 630-fold from lysozyme-treated supernatant fluid to homogeneity, by means of Sephadex G-100 gel filtration, and DEAE-cellulose, phenyl-Sepharose and Blue-Agarose column chromatographies. Its molecular weight was approximately 42,000. Tween hydrolase was partially purified 150-fold by the same purification procedure up to the step of phenyl-Sepharose chromatography and its molecular weight was found to be about 51,000. These activities were stable against heating at 60 degrees C and treatment with non-ionic detergents. Thioesterase hydrolyzed long chain acyl-CoAs (C12-C20), but not Tween 20-80 or beta-naphthyl acetate. On the other hand, Tween hydrolase hydrolyzed Tween 20-80 and beta-naphthyl acetate. On the other hand, Tween hydrolase hydrolyzed Tween 20-80 and beta-naphthyl acetate, but not acyl-CoAs. Both esterases hydrolyzed monoolein, but not diolein, triolein, or phosphatidylcholine.

Acyl Coenzyme A↗
PubMed1981

The structure-hemolysis relationship of oleanolic acid derivatives and inhibition of the saponin-induced hemolysis with sapogenins.

Chikusetsusaponin IV and V, whose genin is oleanolic acid, exhibited weak hemolytic activities. Removal of glucose residue at position 29 of chikusetsusaponin V by partial hydrolysis increased the activity more than 30-fold. Methylation of the carboxyl group at position 28 increased the activity furthermore by about 10-fold, showing HD50 value of 3.77 microM. On the other hand, removal of the sugar chain at position 3 of chickusetsusaponin V by partial hydrolysis completely lost the activity. These facts suggest that the sugar chain at position 3 of oleanolic acid is essential but that at position 29 is pernicious for the activity. The cytolytic agents, whose target has been regarded as membrane cholesterol, were inactivated not only by cholesterol but also by sapogenins such as oleanolic acid, gitogenin and hederagenin. Among saponins tested, akebia saponin B and C were inactivated by cholesterol, but not by the genins, probably because their affinities for the genins are too low to form complexes.

Anti-Bacterial Agents↗