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Biomedical subjects

T Aoyagi

Publications and source records attributed to T Aoyagi.

At least 271 records · Page 15Linked to original sources
PubMed1989

Wall motion asynchrony prolongs time constant of left ventricular relaxation.

To evaluate the effects of wall motion asynchrony on left ventricular (LV) relaxation, we performed atrioventricular sequential pacing with the second stimulation at six epicardial sites in open-chest anesthetized dogs. Myocardial segment lengths in the basal, mid, and apical LV free wall were measured by ultrasonic crystals. The standard deviation of interval from the onset of the QRS complex to that of elongation in each segment length was used as a quantitative index for asynchrony (asynchrony index, AI). The AI increased significantly in all sequential pacing modes compared with the control right atrial pacing. The time constant (T) of LV relaxation derived from exponential fit with zero-asymptote was prolonged significantly in all sequential pacing modes except for pacing at the LV base. In each dog there was a good correlation between changes in AI and T [r = 0.61 - 0.98 (mean = 0.84)]. Since the regional inactivation process of the myocardium is considered to be unchanged during these interventions, we concluded that asynchronous wall motion plays an important role in the impairment of LV relaxation.

Animals↗
PubMed1989

Pathophysiology and evaluation of severity of congestive heart failure on the basis of venous characteristics.

To elucidate the possibility of grading the severity of congestive heart failure by using venous characteristics, we constructed venous pressure-volume curves (PVR) and calculated venous stiffness constants (K). In addition, effects of vasoactive drugs on venous distensibility were studied. A venous pressure-volume curve could be fit well by an exponential curve (r = 0.98 +/- 0.01). The PVR was shifted to the left with an increase in the clinical severity of congestive heart failure. The exponent of these curves, K, increased as the PVR was shifted to the left. K correlated with heart rate (r = 0.52, p less than 0.01), right atrial pressure (r = 0.54, p less than 0.02) and mean pulmonary arterial pressure (r = 0.47, p less than 0.04). Nitroglycerin and amrinone dilated veins and decreased K by 19.6 +/- 6.9% (p less than 0.03) and 14.0 +/- 4.3% (p less than 0.02), respectively. Changes in K (delta K) during the nitroglycerin and amrinone infusions correlated closely with the baseline K (delta K = -0.41 K + 0.22, r = 0.92, p less than 0.01). Therefore, the venodilating effects of these drugs were greater in patients with more severe congestive heart failure. The venous stiffness constant could be useful to grade the severity of congestive heart failure.

Adult↗
PubMed1989

A morphometric study of changes in Dolichos biflorus agglutinin (DBA)-binding pattern of the human gastric parietal cell in association with acid secretion.

Dolichos biflorus agglutinin (DBA) specifically stains the perinuclear region of the human parietal cell that corresponds to the intracellular secretory canalicular membrane at the electron microscopic level (Histochemistry 83: 189, 1985). In the present study, the DBA-staining intensity of the parietal cell was quantitatively estimated in association with gastric acid secretion. Gastric fundic glandular tissues were taken by endoscopic biopsy from 11 healthy males before and after administration of tetragastrin (4 micrograms/kg) or betazol hydrochloride (1 mg/kg). Paraffin sections were prepared and stained with DBA by the ABC method. Light absorbance of the stained parietal cells covering a spot 20.9 microns in diameter was measured using a microspectrophotometer set at wavelength of 365 nm. In all cases, a significant increase in absorbance was recorded after stimulation. The total average of the absorbance before and after stimulation was 0.21 and 0.29, respectively. Electron microscopy revealed that the increase in absorbance was caused by an increase in surface area of the membrane of the intracellular secretory canaliculi.

Adult↗
PubMed1989

Mannostatins A and B: new inhibitors of alpha-D-mannosidase, produced by Streptoverticillium verticillus var. quintum ME3-AG3: taxonomy, production, isolation, physico-chemical properties and biological activities.

Mannostatins have been isolated as part of a program designed to find microorganism-produced inhibitors of alpha-D-mannosidase from Streptoverticillium verticillus var. quintum. They were purified by sequential use of active carbon and Dowex resins and then isolated as colorless powders. Mannostatins A and B have the molecular formula, C6H13NO3S and C6H13NO4S, respectively. They were competitive with the substrate, and the inhibition constants (Ki) of mannostatins A and B were 4.8 x 10(-8) M.

Cyclopentanes↗
PubMed1989

Possible relationship between poly(ADP-ribose)synthetase and formation of antibody against acetylcholine receptors in patients with myasthenia gravis.

We examined the relationship of the serum levels of antibody against acetylcholine receptors to the serum levels of 13 enzymes, including various hydrolytic enzymes, poly(ADP-ribose)synthetase (Poly(ADP-ribose)Syn), and sialyltransferase (NANA-trans), in patients with myasthenia gravis. The patients were divided into two groups, depending on the presence or absence of thymoma. In spite of the absence of significant difference in the absolute levels of individual enzymatic activities between the two groups, the network relationships of such enzymes were quite different between the two groups. Of the 13 enzymes examined, only Poly(ADP-ribose)Syn showed a weak but significant correlation with the level of the antibody in the patients without thymoma. A multivariate study more clearly suggested the relationship between the antibody formation and Poly(ADP-ribose)Syn in the patients without thymoma. Such observations were not found in the patients with thymoma.

Autoantibodies↗
PubMed1989

Suppression of the activities of T-lymphocyte-related enzymes in spleen by administration of an immunosuppressant, 15-deoxyspergualin.

We investigated the effects of both (-) and (+)-enantiomers of 15-deoxyspergualin (DSG), an immunosuppressant, on enzyme networks in spleens of ICR mice. Of the 14 hydrolytic enzymes tested, the activity of dipeptidyl aminopeptidase IV (DAP-IV) was found to be significantly suppressed by the administration of (-)-DSG but not by that of (+)-DSG. In contrast, the activity of N-acetyl-beta-D-glucosaminidase (GlcNAc-ase) was suppressed by the administration of both enantiomers of DSG. Judging from the previous reports of ours and others which suggested specific relations of these enzymes to T-lymphocytes, the above findings may warrant further studies of these enzymes in relation to immunologic functions of the body.

Acetylglucosaminidase↗
PubMed1989

Changes in relationship between blood glucose level and plasma 1,5-anhydroglucitol level in KK mice.

We compared the relationship of the blood glucose level to the plasma 1,5-anhydroglucitol (1,5AG) level between KK mice with abnormal glucose metabolism and ICR mice as controls. Although the plasma 1,5AG level did not show any significant correlation with the blood glucose level in the controls, it tended to logarithmically decrease with the rise in the blood glucose level in KK mice. Thus it is possible that the plasma 1,5AG level is specifically related to the abnormal glucose metabolism in this model of diabetes mellitus and that its routine examination in diabetic patients may help delineate the metabolic derangement in the disease.

Animals↗
PubMed1989

Multiple enzymes related to differentiation of lymphocyte subpopulations in man.

We studied the relation of various enzymes to subpopulations of lymphocytes in man. T cell-rich fractions were separated with a nylon column from mononuclear cells in the buffy coat. Comparing the enzymatic profiles of the two fractions, we found that the difference between the two groups came from the dominancy of B cells and/or macrophages in the former fraction, and from that of T cells in the latter. The enzymes characterizing T cells included N-Ac-beta-D-glucosaminidase (GlcNAc-ase), prolyl endopeptidase (Post-Pro-Enz), and dipeptidyl aminopeptidase IV (DAP-IV), whereas those characterizing B cells and/or macrophages include poly(ADP-ribose) synthetase, leucine aminopeptidase (Leu-AP), AP-B, cathepsin B, sialidase, and AP-A. Inhibitors of these enzymes may lead to modification of the function of T and B cells.

B-Lymphocytes↗
PubMed1988

Lupus nephropathy in New Zealand F1 hybrid mice treated by (-)15-deoxyspergualin.

The effect of (-)15-deoxyspergualin (15-dsp), a new immunosuppressant which was originally separated from the culture filtrate of a strain of Bacillus laterosporus, was evaluated in this study. Various doses of 15-dsp were subcutaneously administered to New Zealand black/white F1 hybrid mice (B/WF1) four times a week starting at 14 weeks of age, just prior to the onset of nephropathy. The life span of the treated animals, studied at 0.6 to 6.0 mg/kg body weights, compared with the control mice was significantly prolonged by 15-dsp treatment (percent survival of the treated mice at 50 to 70 weeks of age was significantly higher than that of the control mice, except that of the 0.6 mg group at 60 wks of age, P less than 0.05 by Fisher's exact test). In the 6.0 mg group of mice, complete suppression of spontaneously progressive splenomegaly with decreased total spleen cells was observed at 24 through 36 weeks of age compared with the same-aged control group of mice (P less than 0.01). Absolute numbers of L3T4+ splenocytes determined by flow cytometry, as well as L3T4+/Lyt2+ ratio, were decreased, while in vitro interleukin 2 production by splenocytes induced with staphylococcal enterotoxin A was significantly enhanced. Serum IgG anti-ds DNA antibody levels, measured by radioimmunoassay in the treated mice, were significantly lower at 24 through 36 weeks of age than those in the control mice (P less than 0.01), and the incidence of significant proteinuria (greater than or equal to 100 mg/dl) in the 15-dsp group was lower at both 32 and 36 weeks of age (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1988

Antimycobacterial activities in vitro and in vivo and pharmacokinetics of dihydromycoplanecin A.

The in vitro activity of dihydromycoplanecin A (DHMP A), a new cyclic peptide antibiotic, was compared with those of antimycobacterial drugs such as streptomycin, isoniazid (INH), rifampin, and ofloxacin against several clinically isolated species of mycobacteria, including Mycobacterium tuberculosis, M. intracellulare, and M. kansasii. DHMP A demonstrated stronger activities than other drugs against all species of mycobacteria tested at concentrations of less than 0.0125 to 25 microgram/ml. A marked synergism between DHMP A and INH was demonstrated by the checkerboard technique against M. tuberculosis, M. intracellulare, and M. smegmatis, and the synergistic effect was observed by treatment of the culture of M. smegmatis with DHMP A for at least 3 h prior to treatment with INH. It was also shown that both absorption and excretion of INH in mice were faster than those of DHMP A. On the basis of these results, combination therapy with DHMP A and INH was successfully carried out in experimental tuberculosis in mice infected with M. bovis Ravenel. After a single intravenous administration of 10 mg of DHMP A per kg, its half-life in serum in mice was about 0.5 h and in dogs it was 5.5 h. A single oral administration to dogs of 12.5 mg/kg gave a peak of 5.0 micrograms/ml at 3 h. In these experiments, urinary recoveries within 48 h were 21.0% in mice and 25.2% in dogs. The tissue distribution level of DHMP A in mice after oral administration was in the order of liver greater than kidney greater than serum greater than spleen = lung. The 50% lethal doses of DHMP A for mice were more than 6,000 mg/kg orally and 1,840 mg/kg intraperitoneally.

Administration, Oral↗
PubMed1988

Treatment of brain tumors with iridium-192 seeds.

Interstitial radiation therapy of brain tumors requires positioning of the radioactive sources with good precision in order to achieve a sufficient dose in the tumor without too much damage to surrounding tissues. A method for application of 192Ir seeds in brain tumors is described and preliminary results in seven patients reported. The method, which uses CT-guided stereotactic localization and computerized dose planning, is at present fairly complicated. The preliminary results are promising and no serious complications have so far been observed.

Adult↗
PubMed1988

Benadrostin, new inhibitor of poly(ADP-ribose) synthetase, produced by actinomycetes. I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Benadrostin, a new inhibitor of poly(ADP-ribose) synthetase was discovered in the fermentation broth of Streptomyces flavovirens MH499-O'F1. It was purified by chromatography followed by solvent extraction and then isolated as colorless prisms. Benadrostin has the molecular formula of C8H5NO4. It was competitive with the substrate, and the inhibition constant (Ki) was 34 microM.

Fermentation↗
PubMed1988

Synthesis of histargin and related compounds and their inhibition of enzymes.

A novel method for the synthesis of histargin and its analogs is described. It includes two kinds of N-alkylation reactions that prevent the formation of side products. The inhibition of enzymes by these compounds was also measured. Some of the compounds strongly inhibited carboxypeptidase B, carboxypeptidase A, carboxypeptidase N (kininase I), and angiotensin converting enzyme.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Protease-inhibitory activities of leupeptin analogues.

Thirty analogues of leupeptin were synthesized and examined for their inhibitory activities against trypsin, papain, plasmin, kallikrein, thrombin and urokinase in vitro. Benzoyl- and alpha-naphthalenesulfonyl-L-leucyl-L-argininal were 8 times more inhibitory to papain, benzyloxycarbonyl-L-pyroglutamyl-L-leucyl-L-argininal 10 times more to trypsin and plasmin, and DL-2-pipecolyl-L-leucyl-L-argininal 25 times more to kallikrein than leupeptin. Against urokinase, only L-pyroglutamyl-L-leucyl-L-argininal exhibited a potent inhibitory activity. alpha-Naphthalensulfonyl-, dansyl- and benzyloxycarbonyl-(2S,3R)-3-amino-2-hydroxy-4-phenylbutyryl-L-leucyl-L- argininal were inhibitory to thrombin.

Fibrinolysin↗