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Biomedical subjects

M Endoh

Publications and source records attributed to M Endoh.

At least 451 records · Page 25Linked to original sources

Selective IgM deficiency: a case study.

We experienced an 85-year-old male patient with selective IgM deficiency. The average levels of his serum immunoglobulins were as follows: IgG, 1,165 mg/dl, IgA 280 mg/dl, and IgM 17 mg/dl. The subpopulations of peripheral blood lymphocytes in this patient were normal, including normal numbers of IgM-bearing lymphocytes. Normal amounts of cells with cytoplasmic IgM were induced by in vitro addition of pokeweek mitogen, and no inhibitory cells or inhibitory factors for in vitro production of IgM were demonstrated in his blood. These results suggest that some defects similar to those in patients with selective IgA deficiency may play a role in the development of selective IgM deficiency.

Aged↗

Dissociation of cyclic AMP and contractile responses to isoprenaline: effects of a dihydropyridine derivative, nicardipine (YC-93), on canine ventricular muscle.

Nicardipine (YC-93), a 1,4-dihydropyridine derivative, inhibited the cyclic AMP phosphodiesterase (PDE) activity of purified PDE in a cell-free preparation. Its inhibitory action on the purified PDE was about seven times that of papaverine. On the other hand, YC-93 did not affect the intracellular cyclic AMP level and the accumulation of cyclic AMP caused by isoprenaline in the isolated canine right ventricular myocardium. YC-93 caused a prominent negative inotropic action which developed gradually to reach a steady level 1 h after its administration. The potency of YC-93 to depress the force of contraction was one tenth that of D600. The dose-response curve for isoprenaline was shifted to the right and downward in the presence of YC-93 in a concentration-dependent manner, and the positive inotropic action of calcium was also inhibited markedly by YC-93. The depressant action of YC-93 on the positive inotropic actions of isoprenaline and calcium was more prominent than that of D600. Although YC-93 is a potent PDE inhibitor in the cell-free preparation, the PDE in the intact cell system may be not accessible to the drug. Thus, it is considered that YC-93 acted as a calcium antagonistic drug on the isolated canine ventricular myocardium, and thereby inhibited the positive inotropic action of isoprenaline without affecting the intracellular accumulation of cyclic AMP caused by isoprenaline.

3',5'-Cyclic-AMP Phosphodiesterases↗

Adenosine antagonizes the positive inotropic action mediated via beta-, but not alpha-adrenoceptors in the rabbit papillary muscle.

In the isolated rabbit papillary muscle, adenosine (1-300 microM) alone scarcely affected the basal tension developed. The positive inotropic action of isoprenaline, mediated via beta-adrenoceptors, was inhibited by adenosine in a concentration-dependent manner. Atropine (0.3 microM) abolish the inhibitory action of carbachol on the isoprenaline-induced positive inotropic action but not affect the inhibitory asction of adenosine. Adenosine failed to inhibit the positive inotropic action exerted by phenylephrine via stimulation of alpha-adrenoceptors in the presence of pindolol (30 nM). The present results indicate that the positive inotropic action was mediated via alpha-adrenoceptors whose subecllular mechanism was not susceptible to the inhibitory action of adenosine as are beta-adrenoceptors.

Adenosine↗

Adenylate cyclase activity of Bordetella organisms. I. Its production in liquid medium.

Abundant adenylate cyclase activity was found in the phase I cultures not only of Bordetella pertussis but also fo B. parapertussis and B. bronchiseptica. The enzyme activity in the culture fluid increased rapidly and reached a peak during the logarithmic growth phase. B. parapertussis and B. bronchiseptica especially produced a high activity of the enzyme in the culture fluid during the logarithmic phase, but little or no activity was detected in the cells throughout the growth period. In the culture of B. pertussis, the intracellular activity was higher than that in the culture fluid. Phase III cultures of these species lacked both the extracellular and intracellular enzyme activities throughout their growth. In the culture of B. parapertussis, accumulation of cyclic AMP was parallel to that of adenylate cyclase activity through the growth periods, but in B. pertussis there was no parallelism from the stationary through the declining phases. The difference in production patterns of the enzyme activity among the species is discussed.

Adenosine Monophosphate↗

Effects of 2-nicotinamidethyl nitrate (SG-75), a new antianginal drug, on the cyclic AMP phosphodiesterase activity.

The effect of a potent coronary vasodilator, SG-75, on the purified cyclic AMP phosphodiesterase of the bovine heart was compared with that of papaverine. SG-75 inhibited the phosphodiesterase activity in a competitive manner, the IC50 being 10 mM. SG-75 was approximately 300 times less potent than papaverine in inhibiting the phosphodiesterase activity. Thus, it is unlikely that the phosphodiesterase inhibition by SG-75 is involved in its vasodilator action.

3',5'-Cyclic-AMP Phosphodiesterases↗

Mechanism of cardiovascular action of trapidil.

In anaesthetized, open-chest dogs N,N-diethyl-5-methyl[1,2,4]triazolo[1,5-alpha]pyrimidine-7-amine (trapidil) in doses of 0.3--3 mg/kg i.v. produced increases in coronary sinus outflow and heart rate and decreases in systemic blood pressure and coronary resistance in a dose-dependent manner. Trapidil produced an increase in myocardial oxygen consumption but virtually no change in coronary arteriovenous oxygen difference. At 1.8 mg/kg i.v. of the drug coronary resistance fell to half of the pre-drug value and coronary sinus outflow almost doubled, and so did myocardial oxygen consumption. In isolated, blood-perfused dog heart preparations, trapidil produced coronary vasodilator and positive inotropic and chronotropic effects. Theophylline produced similar effects. Trapidil was a more positive inotropic than positive chronotropic agent, and so was theophylline but to a lesser degree than trapidil. In producing vasodilator and positive inotropic effects trapidil was about 3 times more effective than theophylline. Trapidil and theophylline inhibited the cyclic AMP phosphodiesterase (PDE) activity in crude extracts prepared from the dog ventricular muscle. In this respect trapidil was nearly 3 times more potent than theophylline. It is suggested that PDE inhibition would be a fundamental mechanism of action of trapidil.

3',5'-Cyclic-AMP Phosphodiesterases↗

Surface properties of LDL-binding lymphocytes in human peripheral blood.

Surface properties of low density lipoprotein (LDL)-binding lymphocytes were evaluated to determine whether LDL binds with a subpopulation of human peripheral blood lymphocytes (PBL). B- and T-cell rich fractions were prepared from PBL using E-rosette formation or nylon reticulum columns. Binding of FITC-labelled LDL with these cell fractions was determined with a fluorescent microscope and a fluorescence-activated cell sorter (FACS II). The specificity of the binding was evaluated by a dose-dependent inhibition of LDL binding with the addition of unlabelled lipoproteins. In parallel studies, surface properties including E-rosette formation, surface immunoglobulins, and receptors for IgG-Fc, as well as human and mouse C3 were examined. LDL binding lymphocytes were enriched in the B-cell rich fraction, and depleted in the T-cell rich fraction. In addition, FITC-LDL binding lymphocytes were selectively collected by the FACS II. These LDL binding cells restored surface immunoglobulins after incubation in serum-free medium following trypsinization. The majority of lymphocytes stimulated by PHA and PWM in vitro bound with LDL. It is concluded that LDL binds with B cells in fresh human PBL, while it binds with B and T cells in mitogen-stimulated lymphocytes. It is suggested that the selective collection of LDL binding lymphocytes by the FACS II can be applied to the evaluation of cellular interaction of these cells in various immunological reactions.

B-Lymphocytes↗

Papillary necrosis and the antinuclear factor.

The cold-reacting antinuclear factor, specific to kidney tissues, was detected transiently in serum specimens from a diabetic patient during an episode of papillary necrosis. Determination of the cold-reacting antinuclear factor is suggested as being useful in evaluating the degree destruction in kidney tissues.

Antibodies, Antinuclear↗

Double immunofluorescence studies on IgA-associated immune-complexes in glomerular deposits in patients with IgA nephropathy.

A study on double immunofluorescent staining of immunoglobulins and complement in IgA-associated immune-complexes of glomerular deposits in patients with IgA nephropathy is described. The components of immune-complexes deposited in kidney tissues included IgA, IgG, IgM, IgE, C3, C3A, properdin, Clq and C4. Although the majority of the deposits consisted of IgA and C3, some deposits showed the coexistence of other classes of immunoglobulins and C3 as well as other types of complement. It was suggested that the immune-complexes deposited in the glomeruli of patients with IgA nephropathy have a polyclonal nature.

Antigen-Antibody Complex↗

Modified open renal biopsy.

One hundred seven cases of open renal biopsy using KAWAMURA-modified forceps have been performed over the past two years under general anesthesia. A sufficient amount of renal tissues for routine histology, immunofluorescence staining and electronmicroscopy were obtained in all 107 cases. There were no complications attributable to the procedure. It is concluded that this procedure using the "KAWAMURA-modified forceps" can be performed easier and faster than the previous techniques of open renal biopsy.

Adolescent↗