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T Kanazawa

Publications and source records attributed to T Kanazawa.

At least 235 records · Page 13Linked to original sources
PubMed1983

[Clinical evaluation of cefotaxime in internal medicine].

Cefotaxime (CTX) was used for 129 cases in respiratory tract and other infections; 57 cases of pneumonia, 20 cases of bronchopneumonia, 20 cases of acute bronchitis, 14 cases of chronic bronchitis, 7 cases of acute exacerbation of bronchiectasia or pulmonary emphysema, 4 cases of suppurative diseases of the lung, 1 case of pyothorax, 1 case of retropharyngeal abscess, 3 cases of pleurisy and 1 case of urinary tract infection. (A case was excepted on clinical evaluation.) CTX was administered by intravenous injection or drip infusion at a daily dose ranging from 0.5 to 8 g, for a term of 2 to 61 days. The total dose patients received ranged from 3 to 226 g. The results obtained were as follows. Clinical effects; excellent in 45 cases, good in 63 cases, fair in 9 cases, poor in 7 cases and unevaluable in 4 cases. The efficacy rate was 87.1% (108/124). Bacteriological effects; eliminated in 30 cases, decreased in 8 cases, unchanged in 2 cases and replaced in 1 case. The elimination rate was 75.6% (31/41). Side effects and abnormal laboratory findings; general itching, fatigue in lower extremities and albuminuria in 1 case each, and anemia in 2 cases. Increased number of eosinophiles and elevated GOT in 1 case each, elevated GOT and GPT in 3 cases and elevated GOT, GPT and A1-P in 2 cases. These symptoms or abnormal laboratory findings disappeared after the discontinuation or termination of CTX therapy. In view of the above, CTX may be considered to be a clinically useful antibiotic against respiratory tract infections.

Adult↗
PubMed1982

Role of Mg2+ in the Ca2+-Ca2+ exchange mediated by the membrane-bound (Ca2+, Mg2+)-ATPase of sarcoplasmic reticulum vesicles.

Sarcoplasmic reticulum vesicles were preloaded with either 45Ca2+ or unlabeled Ca2+. The unidirectional Ca2+ efflux and influx, together with Ca2+-dependent ATP hydrolysis and phosphorylation of the membrane-bound (Ca2+, Mg2+)-ATPase, were determined in the presence of ATP and ADP. The Ca2+ efflux depended on ATP (or ADP or both). It also required the external Ca2+. The Ca2+ concentration dependence of the efflux was similar to the Ca2+ concentration dependences of Ca2+ influx, Ca2+-dependent ATP hydrolysis, and phosphoenzyme formation. The rate of the efflux was approximately in proportion to the concentration of the phosphoenzyme up to 10 microM Ca2+. These results and other findings indicate that the Ca2+ efflux represents the Ca2+-Ca2+ exchange (between the external medium and the internal medium) mediated by the phosphoenzyme. In the range of 0.6-5.2 microM Mg2+, no appreciable Ca2+-Ca2+ exchange was detected although phosphoenzyme formation occurred to a large extent. Elevation of Mg2+ in the range 5.2 microM-4.8 mM caused a remarkable activation of the exchange, whereas the amount of the phosphoenzyme only approximately doubled. The kinetic analysis shows that this activation results largely from the Mg2+-induced acceleration of an exchange between the bound Ca2+ of the phosphoenzyme and the free Ca2+ in the internal medium. It is concluded that Mg2+ is essential for the exposure of the bound Ca2+ of the phosphoenzyme to the internal medium.

Animals↗
PubMed1982

Phosphoenzyme formation from ATP in the ATPase of sarcoplasmic reticulum. Effect of KCl or ATP and slow dissociation of ATP from precursor enzyme-ATP complex.

The ATP-dependent phosphoenzyme formation and its reversal were studied at 0 degrees C and pH 7.0 in the ATPase of sarcoplasmic reticulum. Addition of KCl or several other salts (approximately 100 mM) decreased the maximum rate of ADP-induced dephosphorylation of phosphoenzyme as well as the apparent affinity of the phosphoenzyme toward ADP. High ATP had a similar effect on the latter, whereas it had little effect on the former. In contrast, high KCl or a considerable change in the ionic strength had little effect on the initial rate of phosphoenzyme formation at saturating ATP concentrations. During steady state phosphorylation at 1.0 mM MgCl2 and 5.0 mM CaCl2 in the absence of added KCl, a significant amount of [gamma-32P]ATP remained bound to the enzyme even when the enzyme concentration was much in excess over that of [gamma-32P]ATP. Evidence is presented that this enzyme-ATP complex represents a precursor to the phosphoenzyme. ATP dissociated slowly (0.20 s-1) from this enzyme-ATP complex and addition of high KCl or other salts accelerated its dissociation. In contrast, when the enzyme was complexed with adenyl-5'-yl (beta, gamma-methylene)diphosphonate in the absence of added KCl under these conditions, dissociation of the nucleotide from the complex as estimated in the displacement experiment with [gamma-32P]ATP, was found to be much faster than that of ATP.

Adenosine Triphosphatases↗
PubMed1982

Reaction mechanism of (Ca2+, Mg2+)-ATPase of sarcoplasmic reticulum. The role of Mg2+ that activates hydrolysis of the phosphoenzyme.

The role of Mg2+ in the activation of phosphoenzyme hydrolysis has been investigated with the (Ca2+, Mg2+)-ATPase of sarcoplasmic reticulum vesicles. The enzyme of the native and solubilized vesicles was phosphorylated with ATP at 0 degrees C, pH 7.0, in the presence of Ca2+ and Mg2+. When Ca2+ and Mg2+ in the medium were chelated, phosphoenzyme hydrolysis continued for about 15 s and then ceased. The extent of this hydrolysis increased with increasing concentrations of Mg2+ added before the start of phosphorylation. This shows that the hydrolysis was activated by the Mg2+ added. The Mg2+ which activated phosphoenzyme hydrolysis was distinct from Mg2+ derived from MgATP bound to the substrate site. The Mg2+ site at which Mg2+ combined to activate phosphoenzyme hydrolysis was located on the outer surface of the vesicular membranes. During the catalytic cycle, Mg2+ combined with the Mg2+ site before Ca2+ dissociated from the Ca2+ transport site of the ADP-sensitive phosphoenzyme with bound Ca2+. This Mg2+ did not activate hydrolysis of the ADP-sensitive phosphoenzyme with bound Ca2+, but markedly activated hydrolysis of the ADP-insensitive phosphoenzyme without bound Ca2+. It is concluded that during the catalytic cycle, Mg2+ activates phosphoenzyme hydrolysis only after Ca2+ has dissociated from the Ca2+ transport site of phosphoenzyme.

Animals↗
PubMed1982

Purification of cardiac sarcolemmal vesicles: high sodium pump content and ATP-dependent, calmodulin-activated calcium uptake.

Highly purified vesicles of cardiac sarcolemma were prepared from a homogenate of canine ventricular muscle by density gradient centrifugation. The preparation showed an extremely high content of (Na+,K+)-ATPase. The steady state levels of Na+-dependent phosphoenzyme formation in the presence of Triton X-100 and the specific ouabain binding in the absence of Triton X-100 were, respectively, 773 and 907 pmol.mg-1 under the optimum conditions. On the other hand, the amount of Ca2+-dependent phosphoenzyme formed in the absence of Triton X--100 was less than 2 pmol.mg-1. This demonstrates that the preparation was virtually free of contaminant sarcoplasmic reticulum fragments. The preparation showed ATP-dependent Ca2+ uptake. Almost all the Ca2+ accumulated on the addition of ATP was rapidly released by the subsequent addition of NaCl. This finding gives evidence that the ATP-driven Ca2+ pump exists in the cardiac sarcolemma. The Ca2+ uptake was unaffected by 2 microM digitoxin, 1 microM monesin, and 200 microM dinitrophenol. These results exclude the possibility that transmembrane gradients of Na+ and H+ were involved in this Ca2+ uptake. The Ca2+ pump was activated by calmodulin. The concentration of calmodulin giving a half-maximum activation was 0.05 micrograms.ml-1, which is equivalent to 3 nM. This activation was removed by addition of trifluoperazine, a specific inhibitor of calmodulin.

Adenosine Triphosphate↗
PubMed1982

Vasodilator action of KB-944, a new calcium antagonist.

Vasodilator action of diethyl 4-(benzothiazol-2-yl)benzylphosphonate (KB-944) was mainly examined in comparison with papaverine in isolated perfused heart and anesthetized or conscious dogs. In isolated perfused heart, KB-944 (1-30 micrograms/heart i.a.) and diltiazem (1-30 micrograms/heart i.a.) produced a dose-dependent increase in coronary flow, and dose-dependent decrease in the heart rate and the myocardial contractile force. On the other hand, papaverine (3-100 micrograms/heart i.a.) produced a dose-dependent increase in coronary flow and heart rate, and did not practically affect the myocardial contractile force. KB-944 was about 3 times as active as papaverine and diltiazem on the percent increase of coronary flow. In anesthetized dogs, KB-944 (0.03-0.3 mg/kg i.v. or 10 mg/kg i.d.), diltiazem (0.03-0.3 mg/kg i.v. or 10 mg/kg i.d.) and papaverine (0.1-1 mg/kg i.v.) significantly increased the coronary blood flow with hypotension. Simultaneously, KB-944 and diltiazem decreased the heart rate, whereas papaverine increased it. Furthermore, KB-944 and diltiazem selectively increased the coronary blood flow more than the carotid blood flow, though papaverine increased the carotid blood flow more than the coronary blood flow. In case of i.v. route, KB-944 and diltiazem were about 5 times as active as papaverine on the percent increase of coronary blood flow. In case of i.d. route, the effect on coronary blood flow and heart rate induced by KB-944 was quantitatively similar to that induced by diltiazem, although the decrease in blood pressure induced by diltiazem was lesser than that produced by KB-944. In conscious dogs, KB-944 (0.03-0.3 mg/kg i.v. or 10-100 mg/kg p.o.) produced a dose-dependent increase in coronary blood flow and heart rate. In case of i.v. route, this vasodilator activity of KB-944 was 10 times as potent as that of papaverine. Thus, KB-944 is a more potent coronary vasodilator. Furthermore, KB-944 is well absorbed from the intestinal tract, and produces a long-acting increase in the coronary blood flow.

Anesthesia↗
PubMed1982

Vasodilator mechanism of KB-944, a new calcium antagonist.

The vasodilator mechanism of diethyl 4-(benzothiazol-2-yl)benzylphosphonate (KB-944) was investigated in anesthetized dogs and isolated aortic and taenia caecum preparations. In anesthetized dogs, the vasodilator effect of KB-944 was not inhibited by propranolol, atropine, diphenhydramine and aminophylline, and did not potentiate the coronary vasodilator action of adenosine. In isolated dog coronary arteries, KB-944 as well as verapamil inhibited the potassium-induced contraction in a concentration-dependent manner. The inhibitory effects of KB-944 and verapamil were overcome by elevating the calcium concentration of the bath solution and a competitive antagonism was found between calcium ions and both compounds. In isolated rabbit aorta, KB-944 (10(-5)--10(-7) mol/l) inhibited potassium-induced contraction in a dose-dependent manner, though KB-944 (3 x 10(-5)--3 x 10(-4) mol/l) slightly inhibited noradrenaline(norepinephrine)-induced contractions. In isolated taenia caecum, KB-944, diltiazem and nifedipine produced a shift to the right of dose-response curves for calcium in a competitive fashion, the pA2 values being 6.84 for KB-944, 6.96 for diltiazem and 9.80 for nifedipine. From these results, it would be that interference with calcium influx contributes to the vasodilator activity of KB-944.

Adenosine↗
PubMed1982

Antihypertensive effect of KB-944, a new calcium antagonist, in conscious normotensive and hypertensive rats.

Hypotensive effect of KB-944 was examined in comparison with diltiazem and nifedipine in normotensive rats, spontaneously hypertensive rats (SHR), renal hypertensive rats and deoxycorticosterone acetate(DOCA)-NaCl hypertensive rats, all in a conscious state. KB-944, diltiazem and nifedipine showed dose-dependent antihypertensive effects in the three different types of hypertensive rats as well as normotensive rats. The relative potency of the test drugs decreased in the following order: nifedipine greater than KB-944 greater than diltiazem. The doses of KB-944 leading to a decrease in systolic blood pressure of 20% of pretreatment level were estimated to be 32.8 mg/kg in normotensive rats, 5.1 mg/kg in SHR, 6.4 mg/kg in renal hypertensive rats and 5.4 mg/kg in DOCA-NaCl hypertensive rats, respectively. The hypotensive effect of KB-944 lasted longer than those of diltiazem or nifedipine. KB-944 and diltiazem increased heart rate in normotensive rats and renal hypertensive rats, though in SHR and DOCA-NaCl hypertensive rats both drugs tended to decrease heart rate. On the other hand, nifedipine increased the heart rate in all types of rats. In SHR, tolerance of KB-944 was not observed with oral administration for 5 weeks at a daily dose of 30 mg/kg.

Animals↗
PubMed1981

Reaction mechanism of (Ca2+, Mg2+)-ATPase of sarcoplasmic reticulum vesicles. I. Phosphoenzyme with bound Ca2+ which is exposed to the external medium.

Sarcoplasmic reticulum vesicles were phosphorylated with [gamma-32P]ATP in the presence of external Ca2+ without added Mg2+. The phosphoenzyme (EP) formed had tightly bound Ca2+ and was dephosphorylated by ADP. When the external Ca2+ was chelated after phosphorylation, Ca2+ dissociated from the EP and ADP addition no longer induced dephosphorylation. Subsequent addition of CaCl2 caused rapid recombination of Ca2+ and restoration of the ADP sensitivity. These findings show that the dissociation and recombination of Ca2+ took place on the outer surface of the membranes, indicating the existence of EP with bound Ca2+ which was exposed to the external medium (Caout.EP). The Ca2+ affinity of the Ca2+ binding site in Caout.EP was comparable to that of the high affinity Ca2+ binding site in the dephosphoenzyme (E). This shows that phosphorylation is not accompanied by an appreciable reduction in the Ca2+ affinity of the Ca2+ binding site, provided this site is exposed to the external medium. The transition from ADP-sensitive EP to ADP-insensitive induced by Ca2+ chelation was unaffected by Mg2+ in the medium. Mg2+ did not activate hydrolysis of the ADP-sensitive EP with bound Ca2+, whereas it markedly accelerated hydrolysis of the ADP-insensitive EP without bound Ca2+.

Adenosine Diphosphate↗
PubMed1981

Reaction mechanism of (Ca2+, Mg2+)-ATPase of sarcoplasmic reticulum vesicles. II. (ATP, ADP)-dependent Ca2+-Ca2+ exchange across the membranes.

Sarcoplasmic reticulum vesicles were preloaded with unlabeled CaCl2, and 45Ca2+ incorporation into the vesicles was determined by adding 45CaCl2 to the external medium in the presence of ATP and ADP. In the absence of added MgCl2, the steady state rate of the (ATP, ADP)-dependent 45Ca2+ incorporation was extremely low, being in good agreement with that of the Ca2+-dependent ATP hydrolysis which was catalyzed by the membrane-bound (Ca2+, Mg2+)-ATPase. In contrast, it was greatly increased by addition of MgCl2 and became much higher than the steady state rate of the Ca2+-dependent ATP hydrolysis. The kinetic analysis of the results gave support to the probability that the MgCl2 addition markedly shifted the equilibrium of the reaction of Caout . EP and Cain . EP represent phosphoenzymes with bound Ca2+ which is exposed to the external medium and to the internal medium, respectively).

Adenosine Diphosphate↗
PubMed1981

Therapy for urolithiasis with hydroxamic acids. IV. Prevention of infected urinary stone formation with N-(pivaloyl)glycinohydroxamic acid.

With the aim of finding a prospective therapeutic compound with a promising potential for the treatment of urolithiasis, we evaluated the effectiveness of a new potent inhibitor of urease, N-(pivaloyl)glycinohydroxamic acid. The present study revealed that N-(pivaloyl)glycinohydroxamic acid effectively inhibited the alkalinization of urine and the stone formation in vitro and in vivo, due to its strong inhibitory potency against the ureolytic activity of intact Proteus mirabilis. The possibility of the clinical application of this compound in the prevention of struvite stone formation caused by infection of urea-splitting bacteria awaits evaluation of the safety of this compound.

Animals↗
PubMed1981

Antimycotic action of a diamidine compound, 1, 4-bis-(m, m'-amidinophenoxymethyl)-cyclohexane dilactate, on Candida albicans.

The antimycotic action of 1, 4-bis-(m, m'-amidinophenoxymethyl)-cyclohexane dilactate (MAC), a synthetic diamidine compound, on Candida albicans was studied. The minimum inhibitory concentration (MIC) ranged from 3.31 to 6.25 micrograms/ml against both standard and clinically isolated strains. MAC was fungistatic at MIC and weakly fungicidal at the concentration of 100 micrograms/ml. MAC did not affect the cell wall or cause cell lysis. Intracellular constituents, such as 260 nm and 280 nm absorbing materials, were released from the cells by treatment with MAC indicating that MAC affected membrane permeability. The release of 260 nm absorbing material was inhibited by the presence of Ca2+ and Mg2+. Acidic phospholipids such as cardiolipin and phosphatidylglycerol inhibited the anti-Candida activity of MAC, but sterols and lecithin were not inhibitory, indicating that MAC interacted with acidic phospholipids of the cell membrane. Freeze-fracture electron microscopy showed that MAC caused aggregation of membrane particles and patch formation on the P face, which may indicate that MAC is a membrane disrupting agent. It appeared that MAC affected C. albicans at the cell membrane by interacting with acidic phospholipids and caused disorganization of the membrane structure resulting in the release of intracellular constituents without lysis.

Amidines↗