Revealing alterations in heart rate fluctuations during the progression of Chagas disease.

Introduction: The heart rate variability (HRV) continually evolves throughout life, reflecting modifications in the architecture of the sinoatrial node (SAN) and in the regulation of heart rate by the autonomic nervous system (ANS). Both can be considerably affected by Chagas disease, causing important changes in the complex nature of HRV. We aim to evaluate the ability of an index based on the false nearest neighbors method (FN10) to reflect these changes during disease progression.

Impairment of agonist-induced M muscarinic receptor activation by autoantibodies from chagasic patients with cardiovascular dysautonomia.

Previous studies showed that circulating autoantibodies against M muscarinic receptors (anti-MR Ab) are associated with decreased cardiac parasympathetic modulation in patients with chronic Chagas disease (CD). Here we investigated whether the exposure of MR to such antibodies could impair agonist-induced receptor activation, leading to the inhibition of associated signaling pathways. Preincubation of MR-expressing HEK 293T cells with serum IgG fractions from chagasic patients with cardiovascular dysautonomia, followed by the addition of carbachol, resulted in the attenuation of agonist-induced G protein activation and arrestin-2 recruitment.

An Oral Salmonella-Based Vaccine Inhibits Liver Metastases by Promoting Tumor-Specific T-Cell-Mediated Immunity in Celiac and Portal Lymph Nodes: A Preclinical Study.

Primary tumor excision is one of the most widely used therapies of cancer. However, the risk of metastases development still exists following tumor resection. The liver is a common site of metastatic disease for numerous cancers.

Therapeutic effects of Salmonella typhi in a mouse model of T-cell lymphoma.

In this study, we assessed the effectiveness of a live, attenuated Salmonella enterica serovar Typhi (S. Typhi) vaccine strain as a cancer immunotherapy in a mouse model of metastatic T-cell lymphoma. EL4 tumor-bearing C57BL/6J mice immunized with S.

Quantitative analysis of muscarinic acetylcholine receptor homo- and heterodimerization in live cells: regulation of receptor down-regulation by heterodimerization.

Although previous pharmacological and biochemical data support the notion that muscarinic acetylcholine receptors (mAChR) form homo- and heterodimers, the existence of mAChR oligomers in live cells is still a matter of controversy. Here we used bioluminescence resonance energy transfer to demonstrate that M(1), M(2), and M(3) mAChR can form constitutive homo- and heterodimers in living HEK 293 cells. Quantitative bioluminescence resonance energy transfer analysis has revealed that the cell receptor population in cells expressing a single subtype of M(1), M(2), or M(3) mAChR is predominantly composed of high affinity homodimers.

Modulatory effects on myocardial physiology induced by an anti-Trypanosoma cruzi monoclonal antibody involve recognition of major antigenic epitopes from beta1-adrenergic and M2-muscarinic cholinergic receptors without requiring receptor cross-linking.

It has been proposed that anti-myocardial antibodies (Ab) against neurotransmitter (NT) receptors are involved in the immunopathology of chronic Chagas' heart disease. We demonstrated that an anti-Trypanosoma cruzi monoclonal Ab (mAb), CAK20.12, binds to murine cardiac beta-adrenergic and muscarinic acetyl choline (mACh) receptors eliciting abnormal physiological responses on normal heart.

Subtype-specific regulation of the expression and function of muscarinic acetylcholine receptors in embryonic chicken retinal cells.

We examined the effect of long-term agonist exposure on muscarinic acetylcholine receptor expression and function in embryonic chicken retinal cells. Long-term carbachol exposure induced a time- and concentration-dependent decrease in M2, M3 and M4 muscarinic receptor numbers. Kinetic analyses revealed a first-order process with similar rate constants for all three subtypes.