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Biomedical subjects

K Takeda

Publications and source records attributed to K Takeda.

At least 1,369 records · Page 76Linked to original sources
PubMed1979

The effect of bleomycin on prolyl hydroxylase and DNA chain breakage: structure-activity relationship.

The activity of purified prolyl hydroxylase (proline, 2-oxoglutarate dioxygenase, EC 1.14.11.2) was enhanced about 3-fold by addition of bleomycin in the assay mixture. Various members of the bleomycin family, their derivatives and degradation products were investigated for activities against prolyl hydroxylase together with their activities of DNA chain breakage to determine relationships between the structure of bleomycin and its various actions. All the bleomycins with various terminal amine parts and desamide bleomycin stimulated the enzymatic activity but did not exhibit an effect on DNA chain breakage. The stimulatory activity of bleomycin was not decreased by hydrolysis with 0.3 N H2SO4 at 80 degrees C for 6 hours, conditions which liberates the sugar moiety, but was eliminated by hydrolysis with 6 N HCl at 105 degrees C for 24 hours. In contrast both treatments decreased the DNA chain breakage activity of bleomycin. Optical spectral studies revealed that all the bleomycins and their hydrolysates which stimulated the prolyl hydroxylase activity made complexes with ferrous ion, one of the cofactors of this enyzme.

Bleomycin↗
PubMed1979

Extrusion of sodium ions energized by respiration and glycolysis in Escherichia coli.

Extrusion of sodium ion from cells of Escherichia coli was measured using an Na+ electrode. When oxygen was supplied to an anaerobic cell suspension, extrusion of Na+ was observed. The addition of glucose under anaerobic conditions also caused Na+ efflux. The extrusion of Na+ energized by respiration and glycolysis was completely inhibited by a proton conductor, carbonyl cyanide m-chlorophenylhydrazone. These observations are consistent with the view that Na+ transport occurs secondarily to H+ circulation. Interestgly, induction of the melibiose transport system, which is coupled to Na+, greatly enhanced Na+ transport activity.

Anaerobiosis↗
PubMed1979

Effects of niludipine (Bay a 7168) on the cardiovascular system with a note on its calcium-antagonistic effects.

1,4-Dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylic acid-bis-(2-propoxyethyl)-ester (niludipine, Bay a 7168), a newly synthesized vasodilator, was three to ten times more potent than nifedipine in dilating the coronary artery of the canine heart-lung and isolated fibrillating heart preparations, but had weaker direct cardiac depressant effects. This drug had a strong and highly selective calcium antagonistic effect on the smooth muscle and also had stronger vasodilating activity on renal and femoral vascular beds as compared to nifedipine. It inhibited myocardial oxidative metabolism in canine and guinea pig hearts.

Animals↗
PubMed1978

Benzylpenicillin preparations can evoke a systemic anaphylactic reaction in guinea pigs.

All of the five commercially available benzylpenicillin preparations obtained from different sources and a PcG preparation prepared by filtration of a commercial PcG on Sephadex G10 elicited the systemic anaphylactic reactions in guinea pigs which had been immunized with benzylpenicilloyl (BPO)-Ascaris extract conjugate (BPO-As) mixed with aluminum bydroxide gel. These preparations could evoke no such reactions in guinea pigs immunized with BPO-bovine gamma globulin conjugate (BPO-BGG) emulsified with complete Freund's adjuvant. The severity of the systemic anaphylactic reactions correlated significantly with the titers of either 8-day passive cutaneous anaphylactic (8-day PCA) reactions or 4-hr PCA reactions evoked with the same benzylpenicillin preparations. In vitro benzylpenicillin preparation contracted the tracheas of the guinea pigs immunized with BPO-As. These results indicated that the commercially available benzylpenicillin preparations have enough antigenicity to evoke systemic anaphylactic reactions in guinea pigs immunized with BPO-As mixed with aluminum hydroxide gel. Such guinea pigs represent an animal model for investigation of penicillin allergy.

Anaphylaxis↗
PubMed1978

Enzyme immunoassay of a beta-adrenergic agent using beta-galactosidase as label.

Antisera against tetrahydronaphthalenols, which are conformationally rigid derivatives of adrenergic catecholamine, were produced in rabbits immunized with trans-5-amino-6-hydroxy-2-isopropylamino-1,2,3,4-tetrahydronaphthalene-1 -ol (I) conjugated to succinylated bovine serum albumin at the C5 position on the tetralin ring. Antisera were screened by immunodiffusion and further characterized by passive hemagglutination assay using erythrocytes sensitized with trans-I-ovalbumin conjugate and by enzyme immunoassay using trans-I-beta-galactosidase conjugate. Cross-reactivity studies indicated that the antiserum was highly specific for the tetralin structure and for substitution at the C2 position. The antiserum also selectively discriminated the stereoisomers about the C1-C2 bond. The anti-trans-I serum was used to develop EIA for trans-5-hydroxymethyl-6-hydroxy-2-isopropylamino-1,2,3,4-tetrahydronapht halene- 1-ol (IIb), which exhibited strong beta-stimulating activity fairly selective to tracheal muscle, since it recognized trans-IIb to the same degree as trans-I. The assay could detect as little as 100 pg of this compound. The mean recovery of trans-IIb added to plasma was 105%, and values for plasma trans-IIb determined by this immunoassay correlated well with those determined by gas chromatography-mass spectrometry.

Adrenergic beta-Agonists↗
PubMed1978

Sympathetic hyperactivity during hypothalamic stimulation in spontaneously hypertensive rats.

To determine whether sympathetic hyperactivity of hypothalamic origin contributes to keep blood pressures high in spontaneous hypertension, aortic pressures and sympathetic nerve spike potentials were recorded during electrical stimulation of the posterior hypothalamus in urethane-anesthetized normotensive or hypertensive rats. Basal sympathetic nerve activity was higher in spontaneously hypertensive rats than in either normotensive or deoxycorticosterone acetate-salt hypertensive ones even before stimulation began. Blood pressure elevations produced by hypothalamic stimulation were always preceded by substantial increases in amplitude and rate of neural firing. Changes in amplitude could not be quantified, but rates of neural firing accelerated much more in spontaneous hypertensives than in normotensives during stimulation with 50- and 100-muA currents. Similar differences between deoxycorticosterone acetate-salt hypertensives and either normotensives or spontaneous hypertensives were not statistically significant. Nerve activity invariably became quiescent immediately after hypothalamic stimulation was discontinued, and recovery from this poststimulatory inhibition was faster in spontaneously hypertensive than in normotensive rats. Although spontaneous hypertensives generally also had stronger pressor responses to various sympathomimetic stimuli, responses to hypothalamic stimulation were enhanced to a greater extent than those to either norepinephrine or sympathetic nerve stimulation. Because this selectivity indicates participation of mechanisms other than augmented cardiovascular reactivity, further enhancement of responsiveness to hypothalamic stimuli was attributed to the associated increase in sympathetic nerve firing. These results are in accord with the hypothesis that the blood pressure elevation in rats with established spontaneous hypertension is a result, at least in part, of sympathetic hyperactivity emanating from the posterior hypothalamus.

Action Potentials↗
PubMed1978

[Alpha- and beta-adrenoceptor blocking actions of labetalol and effects on the myocardial function, coronary circulation and myocardial energy metabolism thereof (author's transl)].

In the isolated atria, trachea and aorta of the guinea pig and in the heart-lung preparation (HLP) of the dog, labetalol was 3.6 approximately 5.9 times less potent than phentolamine in blocking alpha-adrenoceptors, 1.4 approximately 3.6 times less potent as beta 1-blocker and 6 times less potent as beta 2-blocker than propranolol. Beta 1 and beta 2-blocking actions were 12 approximately 28 and 7 times more potent than alpha-blocking action, respectively. As regards beta 1-blockade, attenuation of the heart rate increase was more prominent than that of the augmentation of the contractile force. Both in the isolated atrial preparation of the guinea pig and in canine HLP, labetalol produced a positive inotropic and chronotropic effect and a slight increase in the coronary flow associated with a slight increase in the myocardial O2 consumption and improvement of the myocardial redox potential. Myocardial extraction and usage of lactate, pyruvate and glucose tended to be decreased and those of FFA decreased significantly. The positive inotropic and chrontropic effect was observed in HLP of 6-hydroxydopamine-pretreated dogs and was abolished with propranolol. Labetalol produced a relaxation of the isolated trachea of the guinea pig, which was inhibited with propranolol. In doses higher than those required for alpha- and beta-adrenoceptor blockade, labetalol produced calcium-antagonistic action.

Adrenergic alpha-Antagonists↗
PubMed1978

[Subacute toxicity test of AMI-U-II, a new amino acid solution for renal failure (author's transl)].

Subacute toxicity test of AMI-U-II was carried out using male and female JCL:SD rats. The animals were given intravenously AMI-U-II (80, 40 and 20ml/kg) or reference solution (80 and 40ml/kg) for five weeks. Tachypnea, depression of spontaneous activity, blepharoptosis and edema of face were observed in rats treated with AMI-U-II or reference solution at highest dose. Food consumptions and gaining body weight were slightly reduced in male of these animals, but water intakes were increased in both sexes. Autopsies of the animals which died during five weeks showed pulmonary congestion and/or edema, ascites and pleural effusion. Microscopically, hydropic degeneration of liver cells and dilation of renal tubules and Bowman's capsules were shown. It seems likely that most of these findings were caused by hypervolumic administration of amino acid solution.

Amino Acids↗
PubMed1978

[The gamma ray peak efficiency determination for volume samples using a radioactive point source (author's transl)].

The peak efficiencies for volume samples in gamma spectrometry of environmental radioactive materials have been determined using a radioactive standard point source. The advantages of the method, as compared with conventional calibration method using standard volume sources, are as follows; 1) The peak efficiencies can be obtained with high accuracy and precision, 2) To be applied easily to any sample container being axial symmetry, 3) The correction for self-absorption can be performed by the simple calculation. On the other hand, the application of the method is restricted to only the cylindrical or coaxial detector.

Mathematics↗
PubMed1978

Mutational biosynthesis of butirosin analogs. II. 3', 4'-Dideoxy-6'-N-methylbutirosins, new semisynthetic aminoglycosides.

A pair of new butirosin analogs was isolated from the fermentation broth obtained by cultivating a neamine-negative mutant of the butirosin-producing organism Bacillus circulans in the medium supplemented with 6'-N-methylgentamine C1a. These antibiotics were characterized and elucidated as 3', 4'-dideoxy-6'-N-methylbutirosins A and B (DMB-A & DMB-B), by chemical and spectroscopic studies. DMB-A and DMB-B exhibited broad-spectrum antibacterial activities with in vitro potency similar to or slightly less than that for the butirosin A, with the exception of strains of Pseudomonas aeruginosa and Serratia marcescens against which they exhibited activities equal to or slightly greater than that for butirosin A. As expected, they exhibited stronger activities against butirosin-resistant organisms which contain acetylating enzymes AAC(6')-I and AAC(6')-IV, and phosphorylating enzyme APH(3')-II. They were also active against some of the clinical isolates resistant to butirosins, dibekacin and/or gentamicin. The acute intravenous toxicity in mice of the DMB complex (B:70 APPROXIMATELY 80%) was somewhat less than that of the butirosin A.

Animals↗
PubMed1978

Mutational biosynthesis of butirosin analogs. III. 6'-N-methylbutirosins and 3', 4'-dideoxy-6'-c-methylbutirosins, new semisynthetic aminoglycosides.

Two pairs of butirosin analogs were isolated from the fermentation broths obtained by cultivating a neamine-negative mutant of the butirosin-producing organism Bacillus circulans in the medium supplemented with 6'-N-methylneamine and gentamine C2, respectively. These amtibiotics were characterized as 6'-N-mentylbutirosins A and B (NMB-A & NMB-B), and 3', 4'-dideoxy-6'-C-methylbutirosins A and B (DCB-A & DCB-B), respectively, by chemical and spectroscopic studies. NMB-A and NMB-B exhibited broad-spectrum antibacterial activities with in vitro potency similar to or slightly less than that for butirosin A, but with greater activities against butirosin-resistant strain which contains acetylating enzyme AAC-(6')-I. The activities of NMB-A and NMB-B against Pseudomonas aeruginosa strains were relatively weak. DCB-B had broad-spectrum activity, and exhibited greatly improved activity against butirosin-resistant organisms which contain acetylating enzymes AAC(6')-I and AAC(6')-IV, and phosphorylating enzyme APH(3')-II. These new butirosin analogs were also active against some of the clinical isolates resistant to butirosins, dibekacin and/or gentamicin.

Anti-Bacterial Agents↗