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Biomedical subjects

I Suzuki

Publications and source records attributed to I Suzuki.

At least 361 records · Page 20Linked to original sources
PubMed1981

Pre- and postsynaptic alpha-adrenergic effects of the antihypertensive drug budralazine.

Cardiac presynaptic and vascular postsynaptic alpha-adrenergic effects of 1-[2-(1,3-dimethyl-2-butenylidene)hydrazino]phthalazine (budralazine) were studied in comparison with those of hydralazine. Budralazine was about 3 times less potent than hydralazine in producing tachycardia in spontaneously hypertensive and normotensive rats when compared at equihypotensive doses. In normotensive pithed rats, budralazine at 3 mg/kg i.v. affected neither the tachycardiac response to cardioaccelerator nerve stimulation nor the inhibition of clonidine of the stimulation-induced tachycardia. As the dose was increased to 6 and 12 mg/kg i.v., however, budralazine not only inhibited transiently the sympathetic tachycardia but also enhanced the clonidine bradycardia, although this drug was almost without effect on resting heart rate. These effects of budralazine on the heart rate response in the stimulated rats were partially but significantly antagonized by pretreatment with phentolamine. Hydralazine (3 mg/kg i.v.) differed from budralazine in that its transient inhibition of the stimulation-induced tachycardia was not modified by phentolamine and it produced an acceleration of the recovery of clonidine bradycardia as well as an increase in resting heart rate. Budralazine (3--12 mg/kg i.v.), like hydralazine (0.3 and 3 mg/kg i.v.), antagonized pressor responses to noradrenaline and phenylephrine but did not affect the tachycardia produced by both agonists in normotensive pithed rats. Based on these results, a possible mechanism of hypotensive and weak tachycardiac actions of budralazine is discussed in relation to that of hydralazine.

Animals↗
PubMed1981

First rib resection in the treatment of the thoracic outlet syndrome.

The thoracic outlet syndrome is now generally accepted as an entity that involves all neurovascular compression symptoms of the upper extremities at the tight thoracic outlet. We have treated 19 patients who developed significant symptoms of neurological, arterial or venous compression. Twelve patients presented predominantly and their angiograms demonstrated tight thoracic outlets as the underlying cause of vascular compression. Twenty three first rib resections were performed through the transaxillary approach with apparently complete relief of the syndrome. The similar etiology of the thoracic outlet syndrome and subclavian vein thrombosis was discussed on the basis of angiographic findings. We emphasize to thoracic and cardiovascular surgeons that first rib removal through the transaxillary route is an easy and safe method as a modified thoracoplasty.

Adolescent↗
PubMed1980

Cytochrome oxidase of Nitrobacter agilis: isolation by hydrophobic interaction chromatography.

Cytochrome oxidase has been purified from Nitrobacter agilis using hydrophobic interaction chromatography. The purified preparation contained 3-5% phospholipid and migrated as a single band during polyacrylamide gel electrophoresis under nondissociating conditions, but appeared as three bands in the presence of sodium dodecyl sulfate and 6 M urea. These three bands corresponded to molecular weights of 37 000, 25 000, and 13 000. The absorption spectra of cytochrome oxidase isolated from Nitrobacter were similar to those reported for a-type cytochrome oxidase from other sources and exhibited absorption maxima at 420 and 600 nm when oxidized and 443 and 606 nm when reduced. The purified enzyme reacted both with horse heart and Nitrobacter cytochrome c. The enzymatic activity depended upon the pH of reaction mixture, with the maximum activity at pH 6.5 and 7.5 for Nitrobacter and horse heart cytochrome c, respectively. The activity of the purified enzyme was inhibited by cyanide, azide, and diethyl dithiocarbamate.

Chromatography, Liquid↗
PubMed1979

Purification and characterization of two lectins from Aloe arborescens Mill.

Two lectins have been isolated from leaves of Aloe arborescens Mill by salt precipitation, pH-dependent fractionation and gel filtration. One lectin (P-2) has a molecular weight of approximately 18,000, consists of two subunits (alphabeta) and contains more than 18% by weight of neutral carbohydrate. The smaller subunit (alpha) has a molecular weight of approximately 7,500 and the larger subunit (beta) a molecular weight of approximately 10,500. The other lectin (S-1) has a molecular weight of approximately 24,000, consists of two subunits (gamma2) with a molecular weight of approximately 12,000 and contains more than 50% by weight of neutral carbohydrate. An interesting feature of the amino acid compositions of these lectins is the high proportion of acidic amino acids, such as aspartic acid and glutamic acid, and the low proportion of methionine and histidine. S-1 has a strong hemagglutinating activity. On the other hand, P-2 has not only hemagglutinating activity but also mitogenic activity on lymphocytes, precipitate-forming reactivity with serum proteins, one of which is alpha2-macroglobulin, and complement C3 activating activity via the alternate pathway.

Aloe↗
PubMed1979

Effect of dietary protein content on the activity of rat liver asparagine synthetase.

The activity of rat liver asparagine synthetase [EC 6.3.1.1]increased when animals maintained on 25% protein diet were placed on 15% or 6% protein diet. The enzyme activity level rose within one day, reached a maximum in 7 or 10 days after switching the diet and thereafter dropped gradually. During the purification of the enzyme from rats on 25% or 6% protein diet, the yield and increase of the specific activity were similar in the two groups. Combination of the liver extracts from two such groups demonstrated that the amount of endogeneous inhibitors of the enzyme did not change on replacing the diet. The elevation of the enzyme activity in rats fed 6% casein diet was suppressed by an injection of cycloheximide or actinomycin D. It is suggested that the change in the enzyme activity was due to alteration of the amount of the enzyme.

Animals↗
PubMed1979

A B lymphocyte mitogen extracted from a fungus Peziza vesiculosa.

A water-soluble mitogen was extracted with hot-water from the fruiting bodies of a fungus, Peziza vesiculosa, collected in the wild. The active substance, named vesiculogen, was able to stimulate selectively murine B cells because mitogenic activity was observed in the spleen cell cultures of congenitally athymic nude mice, but not in the thymus cell cultures. The possibility that the mitogenicity of vesiculogen was due to lipopolysaccharide was denied completely by the following evidence: 1) lipopolysaccharide in vesiculogen was undetectable(less than 0.001% in the Limulus test), 2) vesiculogen was able to stimulate strongly DNA synthesis of spleen cells from C3H/HeJ mice, and 3) the mitogenic activity of vesiculogen was not inhibited by polymyxin B. Vesiculogen increased antigen-nonspecifically the number of direct plaque forming cells to sheep erythrocytes, horse erythrocytes, and trinitrophenylated-horse erythrocytes. This result shows that vesiculogen acts as a polyclonal B cell activator on murine spleen cells.

Animals↗
PubMed1979

[Cardiovascular pharmacology of cinepazide, a new cerebral vasodilator (author's transl)].

Cardiovascular effects of cinepazide were compared with those of cinnarizine and papaverine. Cinepazide (3-30 mg/kg, i.v.) produced a dose-related and transient increase in vertebral, carotid, renal and femoral arterial flow as well as cardiac output and a decrease in total peripheral resistance in anesthetized dogs. The magnitude and duration of mesenteric vasodilatation induced by cinepazide was much greater as compared to other vascular effects, and these effects were associated with a prolonged hypotension. The drug exerted positive inotropic and chronotropic actions, the latter being followed by bradycardia with the highest dose. Cinnarizine (0.3-3 mg/kg, i.v.) produced a greater increase in vertebral blood flow with bradycardia and papaverine (0.1-1 mg/kg, i.v.) produced a remarkable carotid vasodilatation with cardiac stimulation. Both reference drugs decreased renal blood flow. Cinepazide (30 mg/kg, i.v.) potentiated the vertebral vasodilator response of dogs to intravertebral adenosine and cyclic AMP, while cinnarizine (3 mg/kg i.v.) reduced their vasodilator effects. Intravertebral cinepazide(1-10 mg), like cinnarizine (0.1-1 mg) and papaverine (0.1-1 mg), increased vertebral blood flow in a dose-related manner and the effect was partially inhibited by intravenous pretreatment with aminophylline but not by pretreatment with autonomic antagonists. These antagonists did not modify the cinnarizine effect. Cinepazide resembled cinnarizine and papaverine in that the drug antagonized rabbit aortic contraction induced by KCl, norepinephrine or CaCl2.

Animals↗