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Biomedical subjects

R Arana

Publications and source records attributed to R Arana.

At least 19 recordsLinked to original sources
PubMed1999

Activation of nitric oxide signaling through muscarinic receptors in submandibular glands by primary Sjögren syndrome antibodies.

Primary Sjögren Syndrome is a chronic autoimmune disease characterized by exocrine gland dysfunction. Here we present evidence of the activation of nitric oxide signaling cascade by circulating antibodies of patients with Sjögren Syndrome in rat submandibular glands. Constitutive nitric oxide synthase and cyclic GMP levels are modulated by Sjögren IgGs through the activation of muscarinic acetylcholine receptors on the glands. The effects are similar to those produced by the agonist carbachol and blocked by the antagonist atropine. The involvement of M1 subtype of muscarinic receptors is proposed since both a synthetic peptide homologous to an extracellular domain of M1 receptor and pirenzepine, a selective M1 antagonist, partially blocked the effects. We conclude that Sjögren Syndrome antibodies can activate nitric oxide signaling in submandibular glands by interacting with muscarinic acetylcholine receptors.

Adult↗
PubMed1999

[A hydatid cyst in the vena cava inferior and right atrium with venous flow obstruction and pulmonary dissemination].

We report the case of a 62-year-old female patient operated for a hepatic hydatid cyst that years later was found to have a hydatid cyst in the inferior vena cava and right atrium that was the source of disseminated pulmonary spread of the disease and occlusion of the inferior vena cava blood flow. Cardiac hydatid disease is very uncommon and is frequently associated with a poor prognosis. The literature for hydatid disease of the heart is reviewed and the clinical and echocardiographic relevant findings of this patient are discussed.

Cardiomyopathies↗
PubMed1999

[Congenital aneurysm of the sinus of Valsalva ruptured to right ventricle with a ventricular septal defect and aortic regurgitation].

We report the case of a patient with a congenital aneurysm of the sinus of Valsalva ruptured in the right ventricle, aortic valvular regurgitation and ventricular septal defect that remained asymptomatic for many years and presented clinically with severe volume overload of the heart and congestive heart failure. We describe the anatomic, echocardiographic and angiographic findings of this unusual entity with a review of the literature.

Adult↗
PubMed1999

[Churg-Strauss syndrome with pericardial and myocardial involvement].

We report the case of a 63-year-old female diagnosed with Churg-Strauss syndrome with both pericardial tamponade and myocardial involvement with congestive heart failure. Allergic granulomatosis and angiitis (Churg-Strauss syndrome) is classically characterized by hypereosinophilia and systemic necrotizing vasculitis of medium and small arteries in patients with previous allergic rhinitis or bronchial asthma. Subsequently the disease has been shown to be associated with cardiac involvement and is responsible for higher morbidity and mortality. The literature for Churg-Strauss syndrome of the heart is reviewed and recent advances in the clinical management of the disease according to appropriate therapeutic strategies are recommended.

Cardiac Tamponade↗
PubMed1998

Autoantibodies against lacrimal gland M3 muscarinic acetylcholine receptors in patients with primary Sjögren's syndrome.

PURPOSE: The authors demonstrated that immunoglobulin G, present in the sera of patients with primary Sjögren syndrome (pSS), could recognize and activate muscarinic acetylcholine receptors (mAChRs) of rat exorbital acrimal gland. METHODS: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, and radioligand binding and biologic assays were used to demonstrate autoantibodies against mAChRs. RESULTS: These autoantibodies recognized by means of SDS-PAGE and immunoblotting assay a band of approximately 70 kDa expressed on lacrimal gland membranes that comigrated with the peak of labeled mAChRs. Moreover, pSS IgG were able to inhibit, in an irreversible manner, the binding of [3H]quinuclidinyl benzilate to mAChRs of rat exorbital lacrimal glands and to simulate the biologic effect of mAChR agonists, because they trigger the activation of phosphoinositide turnover. Atropine and 4-diphenylacetoxy-N-methylpiperidine methiodide blocked the effect and carbachol mimicked it, confirming that the M3 subtype mAChRs mediated pSS IgG action. As control, IgG from sera of women without pSS gave negative results on immunoblotting, binding, and biologic assays, thus demonstrating the specificity of the reaction. CONCLUSIONS: Autoantibodies against mAChRs may be considered among the serum factors implicated in the pathophysiology of the development of pSS dry eyes.

Adult↗
PubMed1997

[Cardiac papillary fibroelastoma. Different forms of the clinical presentation].

Papillary fibroelastoma is an uncommon cardiac tumor rarely diagnosed during life. Although most fibroelastomas are incidental findings at autopsy, a few cases have been associated with cardiac symptoms that include angina, arterial embolism and sudden death. We report the case of two patients, a 35-year-old male with an acute myocardial infarction and ventricular fibrillation and a 53-year-old asymptomatic female, with cardiac masses first detected by transthoracic echocardiography. A more detailed morphological study was provided by transesophageal echocardiography. After cardiac surgery, the anatomical study demonstrated that both tumors were papillary fibroelastomas. The literature concerning papillary fibroelastoma is reviewed.

Adult↗
PubMed1997

[Acute endocarditis of the native aortic valve caused by Propionibacterium acnes].

Propionibacterium acnes is often considered to be a contaminant but it has also been found to be the principal pathogen in serious infections. P. acnes is a rare cause of infective endocarditis. It has been suggested that aortic root abscesses are caused by bacteria that are particularly virulent. The strongest risk factor for serious infections by this bacteria is the presence of foreign bodies. A case is presented in which endocarditis of a native aortic valve caused by P. acnes was associated with an aortic root abscess. Transesophageal echocardiography is particularly helpful in the diagnosis of this severe complication of infective endocarditis. The literature for P. acnes endocarditis is reviewed.

Adult↗
PubMed1996

Circulating antibodies against rat parotid gland M3 muscarinic receptors in primary Sjögren's syndrome.

In this study we demonstrate that IgG present in the sera of patients with primary Sjögren's syndrome (PSS) could bind and activate muscarinic acetylcholine receptors (mAChRs) of rat parotid gland. These antibodies were able to inhibit in a non-competitive manner the binding of 3H-quinuclidinyl benzilate (QNB) to mAChRs of purified rat parotid gland membranes. Moreover, IgG from PSS could modify biological effects mediated by mAChR activation; i.e. decrease cAMP, increase phosphoinositide turnover without affecting cGMP. Atropine and 4-DAMP blocked all of these effects, and carbachol mimicked them, confirming the M3 subtype mAChRs mediated PSS IgG action. Neither binding nor biological effect were obtained with IgG from sera of normal women. 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 mAChRs may be another serum factor to be considered in the pathophysiology of the development of PSS.

Adolescent↗
PubMed1994

Circulating antibodies against neurotransmitter receptor activities in children with congenital heart block and their mothers.

In this work we demonstrated that IgG present in the sera of patients with congenital heart block (CHB) and their mothers could bind and activate beta adrenoceptors and muscarinic cholinergic receptors of neonatal heart. These antibodies were able to inhibit in a noncompetitive manner the binding of [3H]QNB and [3H]CGP to muscarinic cholinergic and beta adrenoceptors of purified neonatal rat myocardial membranes, respectively. Moreover, IgG from children with CHB and their mothers could modify biological effects mediated by these neurotransmitter receptors, i.e., heart contractility and cAMP production. Neither binding nor biological effects were obtained using adult instead of neonatal rat atria. Both reactivities (adrenergic and cholinergic) were independent of Ro/SS-A and La/SS-B antibodies and were absent in the sera of normal women of childbearing age and of normal children. It could be concluded that antibodies against cardiac neurotransmitter receptors may be another serum factor (or factors) to be considered in the pathophysiology of the development of CHB.

Adult↗
PubMed1994

Myocardial mitogenic effect of erythropoietin through the activation of Na(+)-K(+)-ATPase activity.

Erythropoietin is considered unique among the hematopoietic growth factor with a specific action on the differentiation and proliferation of erythroid progenitor cells. We have observed a dose-dependent modulatory action of human recombinant erythropoietin (rHuEpo) stimulated the rate of cell growth but at higher ones (3-10 U/ml) inhibited it. The mitogenic action of the hormone is correlated with cardiac membrane Na(+)-K(+)-ATPase activity since concentrations of rHuEpo that increased cell growth stimulated paranitrophenilphosphatase (pNPPase) activity, while those concentrations that inhibit the enzyme markedly bloqued its mitogenic action. Moreover, ouabain (10(-5) M), concentration that inhibits Na(+)-K(+)-ATPase activity, blunted the stimulatory action of rHuEpo on cell proliferation. We also demonstrated that rHuEpo while activated the cardiac membrane Na(+)-K(+)-ATPase was able to alter the contractile action of ouabain on isolated neonatal rat atria. Indeed rHuEpo (1 U/ml) enhanced the non toxic action of the cardiac glycoside attenuating and delaying the onset of the toxic effect of the drug. These results show that rHuEpo has a non hematopoietic cardiac effect, associated with the cardiac Na(+)-K(+)-ATPase activity, that regulates the myocytes growth and the biological action of cardiac glycosides on isolated rat myocardium.

Animals↗
PubMed1994

Antibodies against beta adrenoceptors in mothers of children with congenital heart block.

To determine whether antibodies against beta adrenergic activity interact with neonatal cardiac cell receptors and alter their physiological behaviour. An "in vitro" experimental model measuring the frequency of contraction, the production of cAMP and binding assay on neonatal and adult rat atria was employed. Sera and IgG fraction from mothers of infants with congenital heart block (CHB) interact with neonatal rat atria increasing the frequency of contraction and cAMP production. These effects were abolished by propranolol, pointing to a beta adrenergic participation. IgG also competed with 3H-CGP to beta adrenergic receptors on neonatal cardiac membranes. Neither the contractile nor the cAMP effects or binding assay were obtained using adult instead of neonatal rat atria. Reactivity against cardiac neurotransmitter receptors may be another serum factor(s) to be considered in the pathophysiology of the development of CHB.

Animals↗
PubMed1994

[An analysis of the endoscopies of the biliary tract performed at the Hospital Santo Tomás].

Endoscopic Retrograde Cholangiopancreatography (ERCP) was performed in 146 patients, 93 female and 53 male from 10 to 90 years of age. The patients were referred because it was deemed that it was necessary to perform the procedure to establish or confirm the clinical diagnosis (suspected choledocholithiasis, icterus or abdominal pain of undetermined etiology, pancreatitis or obstruction of prosthesis) and to perform cholangiography and pancreatography, papillotomy, extraction of calculi and placement of biliary prosthesis, as indicated. It was shown that the clinical picture was due to choledocholithiasis in the majority of patients. Stenosis due to inflammatory changes or to tumor were much less frequent. In few patients, there was biliary external fistula, distortion of intrahepatic ducts, cancer of the pancreas or sclerosing cholangitis. Chronic pancreatitis, choledochal granuloma or adenoma, or displacement of a T tube were found occasionally. There were few complications (cholangitis, pancreatitis and hyperamylasemia) and no mortality associated with the procedure.

Adolescent↗
PubMed1993

[Primary cardiac hemangioma. A case report and review of the literature].

A 26-years-old woman, without symptoms, was diagnosed of cardiac tumor by means of two-dimensional echocardiography, magnetic resonance imaging and angiocardiography. The tumor was removed underwent open-heart operation and cardiopulmonary bypass. Histologic study was suggestive of a capillary hemangioma. We present our experience with this case and a review of the literature.

Adult↗
PubMed1986

Modification of sarcolemmal enzymes by chagasic IgG and its effect on cardiac contractility.

It has been shown that sera from chagasic patients contain an antibody which binds to beta-adrenoceptors of myocardium and modulates their activity. Chagasic IgG triggered a marked stimulation of myocardial contractility with an increase in intramyocardial cyclic AMP and inhibition of (Na+ + K+)-ATPase activity. Both the mechanical and enzymatic effects of the IgG could be prevented by beta-adrenoceptor blockade or after the absorption of chagasic IgG with turkey red blood cells. In contrast, guinea pig red blood cells were unable to remove the beta-reactivity of chagasic IgG. These findings suggest that the IgG from chagasic patients increases myocardial contractility by behaving as a beta-agonist. This effect is likely related to stimulation of the adenylate cyclase coupled to the cardiac beta-adrenoceptor.

Adenylyl Cyclase Inhibitors↗
PubMed1986

Chagasic IgG binds and interacts with cardiac beta adrenoceptor-coupled adenylate cyclase system.

It has been previously shown that sera from chagasic patients have an antibody specific for beta adrenoceptors, independently of other tissue-reactive antibodies as the EVI (endocardium, blood vessels, interstitium) system, and it is highly specific to other heart diseases. In this paper we demonstrate that the IgG present in chagasic sera was able to bind to beta adrenoceptors of the heart and also to interact with the membrane bound adenylate cyclase complex, inducing stimulation of enzymatic activity. Moreover, this antibody stimulated contractile activity of guinea pig myocardium, that could be blocked by a specific beta adrenoceptor antagonist. Chagasic IgG inhibited the binding of (-)-(3H)-dyhidroalprenolol to a beta-adrenergic receptor of purified guinea pig myocardial membranes behaving as non-competitive inhibitor. This IgG also exerted a non-competitive inhibition upon the mechanical effect of exogenous norepinephrine.

Adenylyl Cyclases↗
PubMed1984

A circulating IgG in Chagas' disease which binds to beta-adrenoceptors of myocardium and modulates their activity.

It has been shown that sera from chagasic patients with positive EVI serology could act in co-operation with complement or normal human lymphocytes as a partial beta-adrenoceptor agonist increasing the contractile tension and frequency of isolated rat atria, as occurs with IgG purified from chagasic serum. In this paper we demonstrated that IgG present in chagasic patients sera could bind to the beta-adrenoceptors of the heart and stimulate contractile activity of myocardium. The positive inotropic and chronotropic effect could be blocked by the specific beta 1-adrenoceptor antagonist but not by the beta 2-adrenoceptor antagonist. Chagasic IgG inhibited the binding of (-) 3H-DHA to beta-adrenoceptors of purified rat myocardial membranes behaving as non-competitive inhibitors. The reactivity of chagasic serum or IgG with beta 1-adrenoceptor was lost after absorptions with turkey red blood cells. In contrast, guinea-pig red blood cells were unable to remove the beta 1 reactivity of chagasic serum or chagasic IgG. This supports the specificity of beta 1-adrenoceptors of the chagasic IgG and the independence of beta 1-adrenoceptor reactivity in relation to the EVI system. Clinical specificity of the beta 1-adrenoceptor reactivity seems rather high in Chagas' disease since it was lacking in 14 individuals with other cardiopathies, such as ischaemic and rheumatic heart disease, even after heart surgery.

Animals↗
PubMed1981

Chagasic sera alter the effects of ouabain on isolated rat atria. Participation of adrenergic mechanisms.

The effects of chagasic sera, containing an antibody (EVI antibody) which reacts with the plasma membrane of working myocardial cells, on "toxic" and "non-toxic" actions of ouabain upon isolated self beating or paced rat atria suspended in different media, were explored. Although ouabain produced a dose-dependent positive inotropic influence on atria suspended in Krebs-Ringer-bicarbonate (KRB) and in KRB plus normal human serum (KRB + NHS) it did not elicit any significant positive inotropic effect on atria beating in KRB plus EVI positive human chagasic serum (EVI(+)S). Additionally, EVI(+)S dose-response curves of classical signs of digitalis cardiac toxicity shifted to the left. The threshold concentration of ouabain required to elicit the onset of "toxic" effects was higher in control preparations (kept in KRB or KRB + NHS) than in EVI(+)S exposed preparations. (-)-Propranolol attenuated the overall toxic action of ouabain in EVI(+)S and facilitated its positive inotropic influence. In control media, the beta-adrenoceptor blocker failed to modify either the "non-toxic" or the "toxic" effect of ouabain. On the other hand, with control atria, subthreshold exogenous norepinephrine inhibited the positive inotropism of ouabain. The data suggest that an adrenergic mechanism is involved in the action of ouabain on cardiac tissue immersed in an EVI(+)S-containing solution. The foregoing results may explain the severe "toxic" effects observed with cardioactive glycosides when they are used in patients with Chagas' heart disease, even at low doses.

Animals↗