Relevance of biofilms in pediatric tonsillar disease.

In this investigation, we study the relation between chronic inflammation of the tonsils, clinical features, and the presence of biofilms in the crypts in patients presenting with obstructive hypertrophy and recurrent upper airway pathology. Thirty-six patients who needed to undergo a tonsillectomy for obstructive reasons (aged 1 to 6 years), among which none of them had taken any antibiotics 30 days prior to surgery, were included. Samples were examined with hematoxylin-eosin and Gram staining, fluorescent microscopy, and confocal laser microscopy. The predominance of symptoms were those related to obstructive pathology rather than infection (p < 0.01). All patients had tonsillar hypertrophy (grade III or IV), but an association with adenoids hypertrophy was detected in 66.66% of cases (p < 0.05). 77.28% of tonsils presented biofilms in their crypts, but hypertrophy and tonsillar follicle number were not related to the presence or absence of biofilms. Here, we demonstrated that symptoms like harsh raucous sound, tonsillar and adenoids hypertrophy, apnea, and cervical adenopathies are clearly related to the presence of biofilm in tonsils. Our results allow us to propose that biofilms are involved in the pathogenesis of tonsils and adenoids hypertrophy. The prevention of biofilms formation should be focused in the early stages, attempting to restrain bacterial attachment to the respiratory mucosa.

Involvement of the beta-adrenergic system in the cardiac chronic form of experimental Trypanosoma cruzi infection.

Changes in the cardiac beta-adrenergic system in early stages of Trypanosoma cruzi infection have been described. Here, we studied an early (135 days post-infection-p.i.) and a late stage (365 days p.i.) of the cardiac chronic form of the experimental infection (Tulahuen or SGO-Z12 strains), determining plasma epinephrine and norepinephrine levels, beta-receptor density, affinity and function, cardiac cAMP concentration and phosphodiesterase activity, cardiac contractility, and the presence of beta-receptor autoantibodies. Tulahuen-infected mice presented lower epinephrine and norepinephrine levels; lower beta-receptor affinity and density; a diminished norepinephrine response and higher cAMP levels in the early stage, and a basal contractility similar to non-infected controls in the early and augmented in the late stage. The Tulahuen strain induced autoantibodies with weak beta-receptor interaction. SGO-Z12-infected mice presented lower norepinephrine levels and epinephrine levels that diminished with the evolution of the infection; lower beta-receptor affinity and an increased density; unchanged epinephrine and norepinephrine response in the early and a diminished response in the late stage; higher cAMP levels and unchanged basal contractility. The SGO-Z12 isolate induced beta-receptor autoantibodies with strong interaction with the beta-receptors. None of the antibodies, however, acted a as beta-receptor agonist. The present results demonstrate that this system is seriously compromised in the cardiac chronic stage of T. cruzi infection.

Trypanosoma cruzi: Cardiac mitochondrial alterations produced by different strains in the acute phase of the infection.

The parasite Trypanosoma cruzi is the causative agent of Chagas disease. T. cruzi invasion and replication in cardiomyocytes induce cellular injuries and cytotoxic reactions, with the production of inflammatory cytokines and nitric oxide, both source of reactive oxygen species. The myocyte response to oxidative stress involves the progression of cellular changes primarily targeting mitochondria. We studied the cardiac mitochondrial structure and the enzymatic activity of citrate synthase and respiratory chain CI-CIV complexes, in Albino Swiss mice infected with T. cruzi, Tulahuen strain and SGO Z12 isolate, in two periods of the acute infection. Changes in the mitochondrial structure were detected in both infected groups, reaching values of 71% for Tulahuen and 88% for SGO Z12 infected mice, 30 days post infection. The citrate synthase activity was different according to the evolution of the infection and the parasite strain, but the respiratory chain alterations were similar with either strain.

Trypanosoma cruzi: chemotherapeutic effects of clomipramine in mice infected with an isolate obtained from an endemic area.

The susceptibility of Trypanosoma cruzi strains to nifurtimox and benznidazole has been investigated and resistant strains have been described. Some tricyclic drugs are lethal for trypomastigote and epimastigote forms of T. cruzi (Tulahuen strain) and prevent the disease in mice. We investigated whether clomipramine, a tricyclic antidepressant drug with anti-trypanothione reductase and anti-calmodulin effects, could be effective in treating Albino Swiss mice infected with trypomastigotes of a new T. cruzi isolate from a chronic patient from an endemic area of Argentina in two different treatment schedules. Both treatment schedules were effective in reducing electrocardiographic changes and preventing myocardial structural damage. The cardiac beta-receptors low affinity was compensated for by an increment in their density. This probably maintained cardiac function since 70% of the mice survived for more than 2 years even though anti-cruzipain titers remained high. These results demonstrate that clomipramine, clinically used as a neuroleptic, could be a promising trypanocidal agent for the treatment of Chagas' disease.

Thioridazine treatment prevents cardiopathy in Trypanosoma cruzi infected mice.

Trypanosoma cruzi trypanothione reductase is an enzyme that has been identified as a potential target for chemotherapy. Thioridazine inhibits it and prevented cardiopathy in mice infected with T. cruzi Tulahuen strain. As not all T. cruzi strains respond to treatment in the same way, an isolate from a chronic patient (SGO Z12) was used; parasitaemias were studied along with, survival, serology, electrocardiography, histology and cardiac beta receptor function. Parasitaemia in thioridazine (80 mg/(kg day) for 3 days) treated mice was less and lasted for a shorter period (P < 0.01), there were reduced electrocardiographic and histological alterations and significantly improved survival (80% of non-treated died). Treated mice had lower receptor affinity and higher density as a compensatory mechanism, modifying the course of T. cruzi infection (SGO Z12 isolate) and preventing the consequent cardiopathy.

Electrocardiographic characterization in Trypanosoma cruzi reinfected mice.

Chagas' disease, caused by Trypanosoma cruzi, affects approximately 20 million people. There are 3 stages in the disease: acute, intermediate and chronic, the diversity and severity of the symptoms range from a mild electrocardiographic alteration to sudden death. We have previously demonstrated that when reinfections were carried out in the acute phase they produce greater cardiac damage. The aim of the present work was to investigate whether T. cruzi reinfected mice present electrocardiographic abnormalities that could be characteristic and only achieved after reinfections. Of the mice reinfected during the acute phase 100% showed abnormalities from days 90 post-infection, with a predominance of auricle ventricle blocks (67-71%). All the mice reinfected during the chronic infection showed electrocardiographic alteration after 30 days post-first reinfection. Of the mice infected, without reinfection, 60% exhibited electrocardiographic dysfunction at 90 days post-infection. Our results demonstrated that when the host was reinfected in the acute phase, more serious electrocardiographic alterations were developed than when the reinfections were carried out in the chronic stage. Sudden death described in some chagasic patients, might be related to some of the findings described here.

Trypanosoma cruzi trypanothione reductase inhibitors: phenothiazines and related compounds modify experimental Chagas' disease evolution.

Chagas' disease affects about 18 million people and 25% of the population of Latin America is at risk of acquiring Chagas' disease. The chemotherapy of Chagas' disease is still an open field and remains as an unsolved problem. Nifurtimox and benznidazole are currently used to treat this disease, however, both drugs have high toxicity and are mutagenic with the result that the patients frequently fail to follow treatment. T. cruzi enzimes such as trypanothione reductase, represent potential drug targets because they play an essential role in the life of this organism. This enzyme has been isolated, purified and studied by X ray crystallography. Phenothiazines and related compounds inhibit trypanothione reductase and a specially favoured fit is a phenothiazine with a 2- substitued with 2- chloro and 2- trifluoromethyl with a remote hydrophobic patch. The essential phenothiazine nucleus can adopt more than one inhibitory orientation in its binding site. Phenothiazines and related compounds are drugs used in psychiatric treatments. These anti-depressants inhibit trypanothione reductase through the peroxidase/ H2O2/ system, and also exert other trypanocidal effects upon epimastigotes and tripomastigotes forms: clomipramine through an anticalmodulin action; trifluopherazine and thioridazine induced disruption of mitochondria and prometazine provoked serious cell membrane disorganization. Clomipramine and thioridazine were also effective in treatment of mice with experimental Chagas' disease, significantly modifying the natural evolution of the infection; cardiac function and survival of infected and treated animals were not different from non infected animals. Phenothiazines and related compounds are promising trypanocidal agents for treatment of Chagas' disease. Other trypanocidal agents as nifurtimox, benznidazol,Allopurinol, cystein protease inhibitors and others, are also discussed.

Effects of clomipramine on Trypanosoma cruzi infection in mice.

Trypanosoma cruzi, widely distributed in Latin American countries, provokes Chagas disease, characterized by cardiomyopathy and mega-viscera. The drugs used currently for treatment of acute Chagas disease are highly toxic; the side-effects are undesirable and patients may abandon treatment. We have previously demonstrated that clomipramine (CLO) exerts trypanocidal effects upon epimastigotes and trypomastigotes in vitro with anticalmodulin activity. The present study analyses the effectiveness of CLO treatment in mice infected with a low number of T. cruzi, an animal model that reproduces acute, indeterminate and chronic phases of this trypanosomiasis. In this work, our results demonstrated that CLO 5 mg/kg daily for 30 days, or 2 doses of CLO 40 mg/kg given intraperitoneally at 1 h and 7 days after infection, was not toxic for the host, but was effective against the parasite in that parasitaemias became negative and only mild heart structural and electrocardiographic alterations were detected in the chronic phase in the group treated with CLO 5 mg/kg. In mice treated with CLO 40 mg/kg, none of these alterations was detected. Cardiac beta receptor density and affinity returned to normal in the chronic stage in both experimental groups. T. cruzi enzymes such as calmodulin and trypanothione reductase represent potential drug targets. It has been reported that both can be inhibited by CLO, a tricyclic drug used in clinical therapeutics. We have shown that CLO strongly decreased the mortality rate and electrocardiographic alterations; in addition cardiac beta receptor density and heart histology returned to, or close to, normality 135 days post infection. These results clearly demonstrated that CLO treatment modified significantly the natural evolution of T. cruzi infection.

Thioridazine treatment modifies the evolution of Trypanosoma cruzi infection in mice.

Thioridazine, a tricyclic drug, is known to have a direct effect on Trypanosoma cruzi, disrupting the parasites' mitochondria and kinetoplasts. In the present study, the drug was used orally, at 80 mg/kg.day for 3 days, to treat mice inoculated with low numbers of T. cruzi. The drug caused no apparent toxicity in the host. It cleared trypomastigotes from the bloodstream, prevented the histological and functional alterations of the heart normally observed in the chronic phase of the experimental disease, and greatly reduced the mortality rate compared with that in untreated, infected controls. When checked 135 days post-infection, the density of cardiac beta receptors and the cardiac histology of the treated mice were indistinguishable from those of uninfected, untreated controls. The drug is already used to treat humans, as a neuroleptic drug. It appears to be able to prevent acute infection with T. cruzi evolving into chronic disease, at least in mice, and may be a useful base from which to design new agents for the treatment of Chagas disease.

Structural, ultrastructural studies and evolution of Trypanosoma cruzi-infected mice treated with thioridazine.

Thioridazine (THI) is a tricyclic drug that belongs to the phenothiazine series. THI had a lethal effect upon epimastigotes in culture medium in a concentration of 0.5 microM. Trypanocidal effect upon trypomastigotes of Trypanosoma cruzi was observed above 0.5 mM of THI. Ultrastructural studies showed intracellular vacuoles in both parasite forms and mitochondrion reorganization. To analyze the use of THI as a therapy, male mice were inoculated with 7.10(4) trypomastigotes of T. cruzi, Tulahuen strain, and treated with THI for 3 days, with 80 mg/kg/day. Survival and parasitemia of mice treated with lower doses were similar to those observed in the control group (14 days postinfection). THI treatment modified parasitemia levels. They were negative by day 20 p.i. Hearts from control untreated mice presented typical chagasic myocarditis. Hearts from THI-treated mice sacrificed by day 30 p.i. showed inflammatory infiltrates without amastigote nests. Three months postinfection a mild infiltrate located in the interventricular septum was observed. Survival of this group was 9 months. Present results show that THI had a direct effect upon parasitemia, improved survival of treated mice, and modified the evolution of experimental Chagas disease.

Trypanocidal effects of promethazine.

Promethazine is currently used for its antipsychotic and ansiolytic effects. It is a phenothiazine with anticalmodulin action, not toxic for human beings at therapeutic doses. The present results show that promethazine has trypanocidal effect on both epimastigote and trypomastigote stages of T. cruzi; two hundred microM inhibited epimastigote growth in culture medium and 2 microM immobilized and killed bloodstream trypomastigotes. When promethazine (55 mg/Kg/day) was used as treatment of T. cruzi infected mice, it proved effective in reducing parasitemia and it increased the survival of treated animals. Ultrastructural studies suggest that the lethal effect of this phenothiazine is related to a detergent effect that disrupts T. cruzi cell membrane.

Isometric developed tension and histopathology of myocardium of chagasic mice. II.

In a preceding paper we reported the evolution of chagasic cardiopathy in mice inoculated with low number of T. cruzi from 2 days to 75 days post-infection (p.i.). The present work analyzed the contractility, pharmacological response and histopathology of myocardium isolated from chronic chagasic mice from 90 days until 180 days. p.i. Myocardium contractile force reached values similar to controls until 165 days p.i. From this to the end contractility was significantly lower. At 90 days p.i. NE provoked negative inotropic effect or had no effect in 13% of the cases tested. The others had a reactivity to NE similar to normal ventricles. From 105 days until 180 days p.i. NE induced to a positive inotropic effect significantly lower than in normal. ACh effect was significantly smaller from 165 days to the end. Previously ACh ventricles responses were as control. The effects of dibenamine, propranolol and atropine (10-6M) on chagasic ventricles were similar to those observed in normal tissues. At 90 days p.i. the histopathology showed focalized inflammatory infiltrates. At 180 days p.i. fibers fragmentations and loss of typical striated characteristic of cardiac tissue. The abnormal pharmacological response described could be attributed to alterations in cardiac beta and muscarinic receptors probably due to a lower oxygen support. The present paper shows that during chronic Chagas' disease myocardial function and pharmacological reactivity are seriously and definitively compromised.

Isometric developed tension and histopathology of myocardium of chagasic mice. II.

In a preceding paper we reported the evolution of chagasic cardiopathy in mice inoculated with low number of T. cruzi from 2 days to 75 days post-infection (p.i.). The present work analyzed the contractility, pharmacological response and histopathology of myocardium isolated from chronic chagasic mice from 90 days until 180 days. p.i. Myocardium contractile force reached values similar to controls until 165 days p.i. From this to the end contractility was significantly lower. At 90 days p.i. NE provoked negative inotropic effect or had no effect in 13

of the cases tested. The others had a reactivity to NE similar to normal ventricles. From 105 days until 180 days p.i. NE induced to a positive inotropic effect significantly lower than in normal. ACh effect was significantly smaller from 165 days to the end. Previously ACh ventricles responses were as control. The effects of dibenamine, propranolol and atropine (10-6M) on chagasic ventricles were similar to those observed in normal tissues. At 90 days p.i. the histopathology showed focalized inflammatory infiltrates. At 180 days p.i. fibers fragmentations and loss of typical striated characteristic of cardiac tissue. The abnormal pharmacological response described could be attributed to alterations in cardiac beta and muscarinic receptors probably due to a lower oxygen support. The present paper shows that during chronic Chagas disease myocardial function and pharmacological reactivity are seriously and definitively compromised.

Isometric developed tension and histopathology of myocardium of chagasic mice. II.

In a preceding paper we reported the evolution of chagasic cardiopathy in mice inoculated with low number of T. cruzi from 2 days to 75 days post-infection (p.i.). The present work analyzed the contractility, pharmacological response and histopathology of myocardium isolated from chronic chagasic mice from 90 days until 180 days. p.i. Myocardium contractile force reached values similar to controls until 165 days p.i. From this to the end contractility was significantly lower. At 90 days p.i. NE provoked negative inotropic effect or had no effect in 13

of the cases tested. The others had a reactivity to NE similar to normal ventricles. From 105 days until 180 days p.i. NE induced to a positive inotropic effect significantly lower than in normal. ACh effect was significantly smaller from 165 days to the end. Previously ACh ventricles responses were as control. The effects of dibenamine, propranolol and atropine (10-6M) on chagasic ventricles were similar to those observed in normal tissues. At 90 days p.i. the histopathology showed focalized inflammatory infiltrates. At 180 days p.i. fibers fragmentations and loss of typical striated characteristic of cardiac tissue. The abnormal pharmacological response described could be attributed to alterations in cardiac beta and muscarinic receptors probably due to a lower oxygen support. The present paper shows that during chronic Chagas disease myocardial function and pharmacological reactivity are seriously and definitively compromised.

Isometric developed tension and histopathology of myocardium of chagasic mice. I.

Cardiac disease is usually the most serious complication of human infection with Trypanosoma cruzi in our country. This report studies the evolution of the chagasic cardiopathy in mice inoculated with low number of parasites during acute and indeterminate stages in different aspects: contractility, histopathology and pharmacological response. From 2-45 days post infection (p.i.) (acute stage) myocardium contractile force reached higher values than in controls, but norepinephrine (NE) response was significantly lower. Acetylcholine (ACh) caused a negative inotropic effect similar to the observed in control group. In this period cardiac damage evolved to an acute interstitial myocarditis. In the indeterminate phase (45-75 days p.i.) of this parasitosis NE produced either small inotropic effect, negative inotropic effect or had no effect on the ventricles tested. A significantly low ACh effect, sub-endocardiac perivascular fibrosis and necrosis in wall bases were also observed. The abnormal pharmacological response described could be ascribed to modifications in cardiac beta and muscarinic receptors number or affinity. The present results showed that in myocardium isolated from T. cruzi infected mice the histopathology, contractility and pharmacological response were altered from 48 h p.i. reaching a maximum disorder at 60 days p.i.

Isometric developed tension and histopathology of myocardium of chagasic mice. I.

Cardiac disease is usually the most serious complication of human infection with Trypanosoma cruzi in our country. This report studies the evolution of the chagasic cardiopathy in mice inoculated with low number of parasites during acute and indeterminate stages in different aspects: contractility, histopathology and pharmacological response. From 2-45 days post infection (p.i.) (acute stage) myocardium contractile force reached higher values than in controls, but norepinephrine (NE) response was significantly lower. Acetylcholine (ACh) caused a negative inotropic effect similar to the observed in control group. In this period cardiac damage evolved to an acute interstitial myocarditis. In the indeterminate phase (45-75 days p.i.) of this parasitosis NE produced either small inotropic effect, negative inotropic effect or had no effect on the ventricles tested. A significantly low ACh effect, sub-endocardiac perivascular fibrosis and necrosis in wall bases were also observed. The abnormal pharmacological response described could be ascribed to modifications in cardiac beta and muscarinic receptors number or affinity. The present results showed that in myocardium isolated from T. cruzi infected mice the histopathology, contractility and pharmacological response were altered from 48 h p.i. reaching a maximum disorder at 60 days p.i.

Isometric developed tension and histopathology of myocardium of chagasic mice. I.

Cardiac disease is usually the most serious complication of human infection with Trypanosoma cruzi in our country. This report studies the evolution of the chagasic cardiopathy in mice inoculated with low number of parasites during acute and indeterminate stages in different aspects: contractility, histopathology and pharmacological response. From 2-45 days post infection (p.i.) (acute stage) myocardium contractile force reached higher values than in controls, but norepinephrine (NE) response was significantly lower. Acetylcholine (ACh) caused a negative inotropic effect similar to the observed in control group. In this period cardiac damage evolved to an acute interstitial myocarditis. In the indeterminate phase (45-75 days p.i.) of this parasitosis NE produced either small inotropic effect, negative inotropic effect or had no effect on the ventricles tested. A significantly low ACh effect, sub-endocardiac perivascular fibrosis and necrosis in wall bases were also observed. The abnormal pharmacological response described could be ascribed to modifications in cardiac beta and muscarinic receptors number or affinity. The present results showed that in myocardium isolated from T. cruzi infected mice the histopathology, contractility and pharmacological response were altered from 48 h p.i. reaching a maximum disorder at 60 days p.i.

Pharmacological and contractile response of myocardium of Chagasic albino Swiss mice.

The isometric developed tension (IDT) and the pharmacological response of isolated myocardium from T. cruzi infected Albino Swiss mice in the acute and chronic Chagas' disease, were studied. The animals were infected with 7 X 10(4) trypomastigotes, form of T. cruzi, Tulahuen strain for the acute infection and with 45 parasites for the chronic stage. The isolated myocardium from acute and chronic chagasic mice reached IDT levels similar to normal hearts. The addition of norepinephrine (NE) to acute ventricles led to lower IDT values than in control group; this hyporeactivity to NE was absent in the chronic stage. On the other hand, epinephrine (EPI) effects on acute and chronic ventricles lead to significantly higher IDT values when compared with their controls. Propranolol blocked the higher effect of EPI in isolated myocardium from the acute stage, but the hyperreactivity described in the chronic stage could not be inhibited by the beta receptors antagonist. The agonist and antagonist tested act on cardiac plasma membrane beta receptors and their actions modify transmembrane calcium fluxes, so that the present study shows that Chagas' disease modifies the normal behavior of adrenergic beta cardiac receptors in different degree depending on the stage of the trypanosomiasis.

Pharmacological and contractile response of myocardium of Chagasic albino Swiss mice.

The isometric developed tension (IDT) and the pharmacological response of isolated myocardium from T. cruzi infected Albino Swiss mice in the acute and chronic Chagas disease, were studied. The animals were infected with 7 X 10(4) trypomastigotes, form of T. cruzi, Tulahuen strain for the acute infection and with 45 parasites for the chronic stage. The isolated myocardium from acute and chronic chagasic mice reached IDT levels similar to normal hearts. The addition of norepinephrine (NE) to acute ventricles led to lower IDT values than in control group; this hyporeactivity to NE was absent in the chronic stage. On the other hand, epinephrine (EPI) effects on acute and chronic ventricles lead to significantly higher IDT values when compared with their controls. Propranolol blocked the higher effect of EPI in isolated myocardium from the acute stage, but the hyperreactivity described in the chronic stage could not be inhibited by the beta receptors antagonist. The agonist and antagonist tested act on cardiac plasma membrane beta receptors and their actions modify transmembrane calcium fluxes, so that the present study shows that Chagas disease modifies the normal behavior of adrenergic beta cardiac receptors in different degree depending on the stage of the trypanosomiasis.