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  • 1
    Electronic Resource
    Electronic Resource
    A New Oxidative Rearrangement of a Phorbol Derivative (1995)
    s.l. : American Chemical Society
    Journal of natural products 58 (1995), S. 284-287 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50116a022
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  • 2
    Electronic Resource
    Electronic Resource
    Taxoids from the Roots of Taxus × media cv. Hicksii (1994)
    s.l. : American Chemical Society
    Journal of natural products 57 (1994), S. 607-613 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50107a007
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  • 3
    Electronic Resource
    Electronic Resource
    Involvement of nitric oxide synthase and protein kinase C activation on chagasic antibodies action upon cardiac contractility (1996)
    Springer
    Molecular and cellular biochemistry 160-161 (1996), S. 75-82 
    Details
    ISSN: 1573-4919
    Keywords: atria contractility ; protein kinase C ; nitric oxide ; muscarinic cholinergic receptors ; chagasic IgG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We have already demonstrated the presence of antibodies in the sera of chagasic patients with the ability to interact with neurotransmitter receptors triggering several intracellular pathways of transduction signals. Here we show that, chagasic IgG induced protein kinase C (PKC) translocation to rat cardiac membranes and this effect was inhibited by muscarinic cholinergic blockers atropine and AF-DX 116 pointing to the participation of M2 receptors in this effect. It was also able to stimulate nitric oxide synthase (NOS) activity and this action was blunted by phospholipase C (PLC) and PKC inhibitors indicating that the production of nitric oxide (NO) would be the consequence of the cascade of enzymatic pathways triggered by mAChR activation. PKC and NOS activities were involved in chagasic IgG negative inotropic actions on rat isolated myocardium as its effects were blunted by staurosporine and L-N-monomethyl arginine. Furthermore, low concentrations of chagasic IgG inhibited the cardiac mechanical action of carbachol in a non-competitive manner. These data suggested that PKC activation in myocardium by chagasic IgG would be involved in its physiological actions by modulating NOS activity. The participation of PKC-mediated phosphorylation of mAChR leading to receptor desensitization as one of the causes of dysautonomia is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240034
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  • 4
    Electronic Resource
    Electronic Resource
    Circulating antibodies against neonatal cardiac muscarinic acetylcholine receptor in patients with Sjögren's syndrome (1996)
    Springer
    Molecular and cellular biochemistry 163-164 (1996), S. 335-341 
    Details
    ISSN: 1573-4919
    Keywords: muscarinic cholinergic antibodies ; binding assay ; atria contractility ; cAMP and cGMP production ; phosphoinositide hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Isolated congenital heart block may be associated with Primary Sjogren's Syndrome. In this work we demonstrated that IgG present in the sera ofpatients with Primary Sjogren's Syndrome (PSS) could bind and activate muscarinic acetylcholine receptors of rat neonatal atria. These antibodies were able to inhibit in a irreversible manner the binding of 3H-QNB to muscarinic cholinergic receptors of purified rat atria membranes. Moreover, IgG from PSS individuals could modify biological effects mediated by muscarinic cholinoceptors activation, i.e. decrease contractility and cAMP and increase phosphoinositide turnover and cGMP. Atropine blocked all of these effects and carbachol mimicked them; confirming muscarinic cholinergic receptors-mediated PSS IgG action. Neither binding nor biological effect were obtained using adult instead of neonatal rat atria. IgG from sera of normal women were not effective in the studied system. The prevalence of cholinergic antibody was 100% in PSS and was independent of Ro/SS-A and La/SS-B antibodies. It could be concluded that antibody against muscarinic cholinergic receptors may be another serum factor to be considered in the pathophysiology of the development of congenital heart block.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408674
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  • 5
    Electronic Resource
    Electronic Resource
    Inotropic effect of prostacyclin (PGI2) on isolated rat atria at different contraction frequencies (1980)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 313 (1980), S. 95-100 
    Details
    ISSN: 1432-1912
    Keywords: PGI2 ; Myocarium ; Inotropic Effect ; Rate of Contraction ; Catecholamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of a wide range of Prostacyclin (PGI2) concentrations on the Isometric Developed Tension (IDT) of isolated left auricles driven at different frequencies (0.8, 1.6 or 3.3 Hz) were explored. A comparison of the positive inotropism of PGI2, norepinephrine (NE), tyramine and phenylephrine (Phenyl) indicated that PGI2, NE and tyramine enhanced peak tension significantly less at slow (0.8 and 1.6 Hz) than at higher rates (3.3 Hz); whereas Phenyl augmented equally the IDT at all of these three driving frequencies. The positive inotropism evoked by PGI2 was inhibited by (−)-propranolol and also by a treatment with 6-OHDA. Cocaine, normetanephrine and U-0521, augmented the positive inotropic influence of PGI2 on atria paced at a slow rate (0.8 Hz) but not at a faster one (3.3 Hz). These results suggest that the action of PGI2 on atrial contractions is apparently indirect and mediated by the release of tissue catecholamines. In addition the effect of PGI2 and NE at slow and fast rates appears associated with a different relative relevance of the processes which terminate the action of added sympathomimetic agonists, namely, neuronal or extraneuronal uptake as well as metabolization via COMT. These mechanisms seen to be more prominent at slower driving frequencies and could explain the diminished effect of PGI2 and NE on slowly paced atria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00498563
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of phytohemagglutinin-stimulated human lymphocytes on isolated rat atria (1983)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 324 (1983), S. 58-63 
    Details
    ISSN: 1432-1912
    Keywords: Lipoxygenase products ; Lymphocytes ; Inotropic effects ; SRS-A substance ; Atrium ; Rate of contractions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of phytohemagglutinin (PHA) stimulated human lymphocytes on the contractile activity of isolated rat atria was studied. Increased isometric developed tension (IDT) and higher frequency of contractions (FC) were observed shortly after contact of PHA-activated lymphocytes with spontaneously beating rat atria. Since pre-exposure of the lymphocytes to PHA was not necessary and the pharmacologic effects were demonstrated immediately after addition of the lectin, division of the effector cells as a requisite for their action was excluded. Experiments performed with the antibiotic crystallized fromStreptomyces chartreusenis, Ca2+-ionophore A-23187, yielded similar effects. Lymphocyte fractionation studies showed that T-lymphocyte-rich and T-lymphocyte-depleted cell fractions had opposite effects on IDT and FC. The inotropic and chronotropic effects were not modified by (−)-propranolol or antihistaminics. Inhibitor of the synthesis of prostaglandins enhanced the action of PHA-activated lymphocytes but inhibitors of the lipoxygenase pathway: 5,8,11,14-eicosatetraynoic acid (ETYA) and nordihydroguaiaretic acid (NDGA) prevented the increment of IDT and FC. Also, FPL55712, an antagonist of SRS-A abolished the positive inotropic and chronotropic effects of PHA-activated lymphocytes on rat atria. Therefore, a central role for SRS-A in this reaction is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647839
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  • 7
    Electronic Resource
    Electronic Resource
    The elusive link between coronary lesion morphology and dobutamine stress echocardiography results (1997)
    Springer
    The international journal of cardiovascular imaging 13 (1997), S. 395-401 
    Details
    ISSN: 1573-0743
    Keywords: echocardiography ; ischemia ; lesion morphology ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. Coronary lesion angiographic morphology of the complex type is associated to enhanced susceptibility to ischemia during vasodilator adenosinergic stress testing and attributed to the reduced vasodilatory capacity of the damaged endothelium. Whether coronary lesion morphology can also influence the results of adrenergic pharmacologic stress test remains unknown. The aim of our study was to assess the relationship between coronary plaque morphology and dobutamine-atropine stress echocardiography (DASE) results. Methods and results. We analyzed DASE (up to 40 mcg/kg/min plus atropine) and coronary angiography data of 42 patients with single vessel disease and no totally occluded vessel at angiography. 7 patients had angina, 35 had previous infarction. A diagnostic DASE was performed in all patients within 1–10 (mean 4.7 ± 3.4) days before coronary angiography. An angiographic lesion was considered complex when irregular borders and/or intraluminal lucencies, suggestive of ulcer and/or thrombus were present. According to the angiographic lesion morphology (Ambrose classification), 2 groups were identified: Group I, with simple lesion; Group II with complex lesion. The two groups were similar for number of patients (n= 21), age (I=55 ± 11 vs II=53 ± 7 years, p=ns), coronary stenosis severity expressed as% diameter reduction (I=77 ± 14 vs II=78 ± 15%, p=ns), presence of previous infarction (I=17 vs II=18 pts, p=ns). No difference was found in the prevalence of positivity between the two groups (I=72 vs II=62%, p=ns). The two groups achieved a similar peak dobutamine dose (I=32 ± 9 vs II=33 ± 9 mcg/kg/min, p=ns) and peak Wall Motion Score Index (I=1.5 ± 0.26 vs II=1.45 ± 0.28, p=ns). Conclusions. In patients with non occlusive single vessel disease, coronary morphology of complex type is not associated with greater vulnerability to dobutamine induced ischemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005786812375
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  • 8
    Electronic Resource
    Electronic Resource
    Mitogenic effect of erythropoietin on neonatal rat cardiomyocytes: Signal transduction pathways (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 167 (1996), S. 461-468 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mitogenic effect of recombinant human erythropoietin (rHuEpo) on primary cultures of neonatal rat cardiac myocytes was observed. rHuEpo triggered a dose-dependent increase in myocyte proliferation. The hormone effect over optimally grown control culture 1 day after addition was maximum with 0.5 U/ml and was inhibited with anti-rHuEpo. Inhibitors of enzymatic pathways known to be involved in the cytokines intracellular mechanism such as genistein (tyrosine kinase inhibitor), 2-nitro-4-carboxiphenyl-N,N-diphenylcarbamate (phospholipase C [PLC] inhibitor), and 1-(5-isoquinolinylsufonyl)-2-methyl-piperazine (protein kinase C [PKC] inhibitor) prevented the mitogenic action of rHuEpo. Also the inhibition of Na+-K+-ATPase activity by ouabain blunted the stimulatory action of rHuEpo on cell proliferation. The mitogenic action of the hormone was correlated with cardiac membrane paranitrophenilphosphatase (pNPPase) and PKC activity, since concentrations of rHuEpo that stimulate DNA synthesis increased pNPPase and PKC activity. Moreover, the enzymatic inhibition of tyrosine kinase, PLC, and PKC attenuated the stimulatory action of rHuEpo upon cardiac pNPPase activity. In this paper we demonstrate a non-hematopoietic action of rHuEpo showing both mitogenic and enzymatic effect upon primary myocyte cell culture and on pNPPase activity of neonatal rat heart. These effects are related to the capacity of rHuEpo to stimulate Na+-K+-ATPase activity and appear to be secondary to the activation of tyrosine kinase and PKC, indicating that in the rHuEpo mediated mitogenic action on cardiomyocytes involves the activation of the same enzymatic pathways that have been described by other cytokines in different tissues. © 1996 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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