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Biomedical subjects

A Tanabe

Publications and source records attributed to A Tanabe.

At least 127 records · Page 7Linked to original sources
PubMed1987

Synergism between subthreshold concentrations of thrombin and 12-O-tetradecanoylphorbol 13-acetate in platelet activation.

A comparison was made between the time courses and interdependence of platelet aggregation, serotonin release, and cytosolic free Ca2+ concentration in the same sample of platelets loaded with [14C]-serotonin and Ca2+-sensitive photoprotein aequorin. In 100 micrograms/ml aspirin-treated platelets, neither 0.01 U/ml thrombin nor 50nM TPA, an active phorbol ester, induced significant aggregation, serotonin release, or a rise in the intracellular calcium concentration. However, when these two agents were added together, marked aggregation and release were observed without a change in the cytosolic free Ca2+ concentration. No correlation was observed between the extent of the synergistic effects and time of preincubation with TPA. Potentiatory effects of protein kinase C on receptor-mediated agonists need to be considered in platelet activation.

Blood Platelets↗
PubMed1987

A first case of complete remission of beta-interferon sensitive adult T-cell leukemia.

A case of complete remission of adult T-cell leukemia (ATL) induced by beta-interferon is reported. A 46-year-old male was diagnosed as ATL because of the increased number of ATL cells with deeply indented and lobulated nuclei in the peripheral blood, accompanied by elevated values of the lactic dehydrogenase, the alkaline phosphatase, and the calcium in the serum. The result of the cell surface marker analysis of peripheral blood lymphocytes was compatible with ATL and anti-ATL associated antibody (ATLA) was positive. The integration of proviral deoxyribonucleic acid (DNA) of human T-cell leukemia virus type I(HTLV-I) was proved in the peripheral blood lymphocytes using Southern blot hybridization. Since an ordinal chemotherapy was not so effective for this patient, he was treated with 1.8 X 10(7) units of recombinant beta-interferon (beta-IFN) per day for 7 days as one course. After 5 courses of treatment, a markedly favorable response was recognized, and he achieved complete remission. A lower dose of beta-IFN (9 X 10(6) units per day for 3 days as one course, one or two courses per month) has been continued and he has still been in a complete remission state for 10 months. It is concluded that beta-IFN should be used to treat ATL.

Blood Cells↗
PubMed1986

Separable function of platelet release reaction and clot retraction.

Amiloride, a known Na+/H+ exchange inhibitor, inhibited platelet serotonin release in a dose-dependent manner (100 microM for 50% inhibition, and 1mM for the nearly complete inhibition), although amiloride (1mM) accelerated clot retraction when it was measured at decreased platelet concentration. On the contrary, cytochalasin B (10 micrograms/ml) accelerated platelet serotonin release, but it inhibited clot retraction. These results demonstrate that release reaction and clot retraction, both of which are important processes involved in platelet activation, can be functionally separated.

Actins↗
PubMed1986

Phospholipid-sensitive Ca2+-dependent protein kinase from bovine thyroid: characteristics and subcellular distribution of the enzyme and its substrates.

Ca2+-phosphatidylserine-dependent protein kinase activity was demonstrated in whole thyroid homogenates, cytosol, particulate, and membrane fractions. Although Ca2+-phospholipid-dependent protein kinase was difficult to detect in purified thyroid plasma membranes, an EGTA extract of such membranes had this activity. While phosphatidylinositol did not stimulate the enzyme, it enhanced the response to phosphatidylserine in the presence of 10 mmol/L free Ca2+. The enzyme was active at concentrations of free Ca2+ as low as 1 mumol/L but was inhibited at Ca2+ in excess of 500 mumol/L. Bovine thyroid contained endogenous substrates of 38,000 and 33,000 daltons for thyroid or purified spleen Ca2+-phospholipid-dependent protein kinase. The 38,000 dalton polypeptide was present in all the subcellular fractions while the 33,000 dalton substrate was present only in the whole homogenate and cytosolic fraction. The 38,000 dalton polypeptide, like the Ca2+-phospholipid-dependent protein kinase, was released from thyroid plasma membranes by EGTA. Phosphorylation of this substrate was rapid, highly sensitive to Ca2+, and inhibited by chlorpromazine (100 mumol/L) and trifluoperazine chlorpromazine (100 mumol/L) and trifluoperazine (100 mumol/L). Several substrates of a phospholipid-independent, Ca2+-dependent protein kinase with molecular weights of 51,000, 76,000, and 96,000 were also observed. This Ca2+-phospholipid-dependent protein phosphorylation system may be important in the membrane-associated functions of the thyroid.

Animals↗
PubMed1986

[Effect of sulfamonomethoxine and ormetoprim on leucocytozoon infection in chickens].

The preventive effect of sulfamonomethoxine (Smm) and ormetoprim (Omp) medicated in combination against leucocytozoon infection in chickens was tested in field trials. In trial 1, medication was given continuously throughout the experimental period. In trial 2, medication was given for seven days and no medication was given for the next seven days; then this schedule for the medication was repeated throughout the experimental period. In trial 1, almost complete prevention was obtained when Smm and Omp were added to the feed at the level of 12 ppm and 14 ppm, respectively, or at the level of 15 ppm and 5 ppm, respectively. Only a partial effect was obtained, however, when these drugs were used at the level of 9 ppm and 3 ppm, respectively. In trial 2, a nearly complete effect was obtained when Smm and Omp were added to the feed at the level of 18 ppm and 6 ppm respectively, but we found no effect when these drugs were used at the level of 15 ppm and 5 ppm, respectively. There were no significant differences among the groups as to the weight gain.

Animals↗
PubMed1985

Thyroid cell responses to thyrotropin and 12-O-tetradecanoyl-phorbol-13-acetate: translocation of protein kinase C and phosphorylation of thyroid cell polypeptide substrates.

Not all of the effects of thyroid-stimulating hormone (TSH) on the thyroid are mediated by activation of the adenylate cyclase-cyclic AMP system, indicating that other control systems must also exist. Although a calcium-phospholipid-dependent protein kinase (protein kinase C) and specific substrates had been identified in thyroid tissue, their responsiveness to TSH and other stimulators has not been determined. In thyroid cells which had been preloaded with [32P]orthophosphate, TSH and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) increased the phosphorylation of a 33K polypeptide substrate within 5 min in a dose-dependent fashion. The effect was observed with 1 mU/ml TSH and 3 nM TPA and was maximal with 100 mU/ml TSH and 100 nM TPA. The biologically inactive analog of TPA, 4 alpha-phorbol, had no effect. Isobutylmethylxanthine (IBMX) decreased the phosphorylation of the 33K polypeptide and inhibited the effect of TSH and TPA, indicating that the phosphorylation is not mediated by cyclic AMP. TSH and IBMX, but not TPA, augmented phosphorylation of a 38K polypeptide, suggesting involvement of cyclic AMP. In contrast TPA, but not TSH, increased the phosphorylation of 58K and 28K polypeptides. TSH, but not TPA or 4 alpha-phorbol, elevated the cyclic AMP level of thyroid slices. Incubation of thyroid slices with TSH or TPA significantly decreased protein kinase C activity in the 100,000g cytosol fraction and increased it in an extract of plasma membranes. The effect was present within 5 min and was maximal by 30 min. The effect was observed with 100 mU/ml TSH or 1 nM TPA. The stimulation by TSH or TPA of protein kinase C and its translocation from the cytosol to the plasma membranes of thyroid tissue may provide another mechanism for control of thyroid cell metabolism.

1-Methyl-3-isobutylxanthine↗
PubMed1985

Granulopoiesis in patients with congenital neutropenia.

Granulopoiesis was investigated in five patients with congenital neutropenia (CN) (one Kostmann type, four benign forms). In semisolid agar culture, the marrow cells of all five patients produced normal numbers of CFU-c (colony-forming unit-culture). The size and classification of colonies were normal. In suspension culture in vitro with exogenous colony-stimulating factor (CSF) generated from omental-conditioned medium (OMCM), the myeloid precursors of all patients could proliferate and differentiate into normal polymorphonuclear neutrophils (PMNs). But in the absence of exogenous CSF, myeloid precursors of the patient with Kostmann-type CN did not proliferate or differentiate into PMNs at all. In the four patients with benign neutropenia, however, PMNs were found even without exogenous CSF similar to normal individuals. These results suggest that patients with CN may have normal granulopoietic stem cells with normal proliferative and differentiating capacity in response to exogenous CSF. When a small amount of normal human serum was added to normal marrow cultures stimulated by exogenous CSF, the colony growth increased in a superadditive manner. The enhancing activity of serum from neutropenic patients differed from that of normal serum. Especially, the addition of serum from the patient with Kostmann type CN to normal marrow cultures did not show this enhancement effect. The sera of patients with benign neutropenia had less enhancement effect than did normal control serum. These findings might be interpreted as showing an imbalance between CSF enhancer and inhibitors in the patients' serum.

Adult↗
PubMed1985

Termination of ventricular tachycardia by an implantable atrial pacemaker and external pacemaker activator.

An atrial pacemaker was implanted in a patient who had dilated cardiomyopathy, sinus node dysfunction, and drug-resistant ventricular tachycardia (VT). VT episodes were terminated by atrial overdrive pacing using an implanted pacemaker and a newly developed hand-held external programmer/transmitter. Although successful cases of termination of intractable VT by ventricular pacing have recently been reported, the ventricular method might increase the risk of accelerating VT. Atrial overdrive pacing is a safer method since it minimizes the possibility of tachycardia acceleration and, combined with antiarrhythmic drugs, it appeared to be a unique and useful approach for the treatment of drug-resistant VT.

Adult↗
PubMed1985

[Effect of HPS on leucocytozoon and coccidial infection in chickens].

The effect of HPS (halofuginonepolystyrene sulfonate), a derivative of halofuginone with lower toxicity, on natural leucocytozoon and coccidial infection in broiler chickens was evaluated in a floor pen trial. The experiment was conducted from one day to 10 weeks of age. On leucocytozoon infection, HPS added to the diet was completely effective at 60 ppm, fairly effective at 40 ppm and ineffective at 20 ppm. On the other hand, HPS concentrations of 20 ppm, 40 ppm and 60 ppm were completely effective on coccidial infection. HPS at 40 ppm which corresponds to the recommended level of halofuginone (3 ppm) and at 60 ppm had no adverse effect on the weight gain in experimental birds.

Animals↗
PubMed1985

[Effect of sulfaquinoxaline and diaveridine on leucocytozoon infection in chickens].

The preventive effect of sulfaquinoxaline and diaveridine in combination against leucocytozoon infection in White Leghorn female chickens was tested in a field trial. The experiment was initiated when the animals were 120 days old, and it lasted for 10 weeks. The medication was given for the first seven days, and no medication was given for the next seven days; then this schedule for the medication was repeated throughout the experimental period. The almost complete preventive effect was obtained when sulfaquinoxaline and diaveridine were added to the feed at the level of 16 ppm and 4 ppm, respectively, or at the level of 8 ppm and 2 ppm, respectively. On the other hand, only a partial effect was obtained when these drugs were used at the level of 4 ppm and 1 ppm, respectively. These medications had no adverse effect on the weight gain in the experimental birds.

Animals↗
PubMed1985

[Left ventricular peak filling velocity and its relevant factors in hypertrophic hearts].

To evaluate the relevant factors of left ventricular peak filling velocity, M-mode echocardiograms showing the left ventricular cavity were recorded and digitized for 81 patients with hypertrophic hearts (HTH) due to hypertensive heart disease (HHD, n = 30), hypertrophic cardiomyopathy (HCM, n = 25), aortic valve stenosis (AS, n = 9), and HHD and HCM with congestive heart failure (HHD and HCM with CHF, n = 17). Peak rates of increase or decrease in dimension (Vf and Ve, respectively) and peak values of instantaneous circumferential fiber lengthening and shortening velocities (Vf/D and Ve/D, respectively) were determined by computer analysis of left ventricular internal dimensions. Systolic excursion (SE), percent fractional shortening (%FS), mean circumferential fiber shortening velocity (mVcf), thickness of the interventricular septum and posterior wall at end-diastole and the sum of them (WThivs, WThpw, and WThivs + pw, respectively) were also calculated. Their variables were compared with those of normal subjects (n = 24). The results obtained were as follows: Systolic functions in HTH without CHF were similar to those of the normal subjects, but Vf and Vf/D were significantly decreased. Differences in Vf and Vf/D between various HTH without CHF were not significant. In AS and HTH with CHF, Vf and Vf/D were significantly decreased together with systolic function. Vf correlated significantly with WThivs + pw, SE, Ve, and WThivs, and Vf/D with %FS, SE, Ve/D, and Ve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Quantitative assessments of regional myocardial perfusion by digital subtraction angiography].

Regional myocardial perfusion was evaluated by computerized washout analysis of digital subtraction angiography (DSA) images. Diatrizoate meglumine (76% Urografin), 2 to 3 ml, was manually injected into the left main coronary artery. For 26 patients with ischemic heart disease (IHD), 14 patients with cardiomyopathy, and eight patients with normal coronary angiograms, DSA images of myocardial perfusions were obtained in the right anterior oblique projection. These were digitized into an image-processing computer. Time-density curves were constructed in four segments of the left ventricle perfused by the left anterior descending coronary artery (LAD) and the contrast decay half-lives (T1/2) were calculated from the decay phases of the curves, using mono-exponential least square fits. The mean T1/2 was significantly longer in patients with 75% or more LAD narrowing than in those with normal coronary arteries. By contrast, patients with 50% or less LAD narrowing had T1/2 comparable to those with normal coronary arteries. In patients with IHD, there was a significant curvilinear relationship of T1/2 with percent stenosis of the LAD. This indicates that a decrease in regional myocardial flow develops rapidly in coronary stenosis of 70-80% or more. In patients with comparable coronary stenosis, T1/2 was significantly longer in the asynergic regions than in those with normal wall motion, but T1/2 was shorter in regions perfused by collateral vessels. These findings indicate that left ventricular contraction and collateral flow could contribute to regional myocardial perfusion. In addition, patients with hypertrophic and dilated cardiomyopathy had prolonged T1/2 despite normal coronary angiograms, suggesting abnormalities in intramural coronary arteries. Thus, T1/2 derived by computerized washout analysis of DSA myocardial image proved to be a useful index for quantitative evaluation of regional myocardial perfusion.

Adult↗