Non-neuronal cholinergic machinery present in cardiomyocytes offsets hypertrophic signals

Recent work has provided compelling evidence that increased levels of acetylcholine (ACh) can be protective in heart failure, whereas reduced levels of ACh secretion can cause heart malfunction. Previous data show that cardiomyocytes themselves can actively secrete ACh, raising the question of whether this cardiomyocyte derived ACh may contribute to the protective effects of ACh in the heart. To address the functionality of this non-neuronal ACh machinery, we used cholinesterase inhibitors and a siRNA targeted to AChE (acetylcholinesterase) as a way to increase the availability of ACh secreted by cardiac cells. By using nitric oxide (NO) formation as a biological sensor for released ACh, we showed that cholinesterase inhibition increased NO levels in freshly isolated ventricular myocytes and that this effect was prevented by atropine, a muscarinic receptor antagonist, and by inhibition of ACh synthesis or vesicular storage. Functionally, cholinesterase inhibition prevented the hypertrophic effect as well as molecular changes and calcium transient alterations induced by adrenergic overstimulation in cardiomyocytes. Moreover, inhibition of ACh storage or atropine blunted the anti-hypertrophic action of cholinesterase inhibition. Altogether, our results show that cardiomyocytes possess functional cholinergic machinery that offsets deleterious effects of hyperadrenergic stimulation. In addition, we show that adrenergic stimulation upregulates expression levels of cholinergic components. We propose that this cardiomyocyte cholinergic signaling could amplify the protective effects of the parasympathetic nervous system in the heart and may counteract or partially neutralize hypertrophic adrenergic effects.     

Effects of smoking on respiratory capacity and control

The purpose of this study was to provide information concerning the possible early effects of smoking on measures of respiratory capacity and control in young adult female smokers vs. nonsmokers. In particular, maximum performance test results (vital capacity and maximum phonation time) and measures of air pressures and airflows during voiceless, stop‐plosive productions were analysed. Subjects were 45 female nonsmokers and 30 female smokers (total n = 75) between the ages of 18–30 years. For the purposes of this study, a smoker was defined as any subject who, at the time of this study, had smoked at least two cigarettes per day for at least 1 year. All of the subjects in the nonsmoker category were those who, at the time of this study, did not smoke and who had not smoked for at least 5 years prior to the study. Vital capacity measures were conducted using a hand‐held digital spirometer, while maximum phonation productions and voiceless, stop‐plosive pressures and flows were recorded and measured using the Aerophone II Model 6800 (Kay Elemetrics Corp., Lincoln Park, NJ). Results showed significantly lower vital capacities and maximum phonation times in smokers vs. nonsmokers. The maximum phonation time task was also produced with significantly higher mean airflow rates in smokers than nonsmokers. In addition, the smokers were observed to produce significantly greater peak and mean pressures during the voiceless stop‐plosive task than the nonsmokers. A weak, but significant correlation was observed between the number of days the subject had smoked and the mean pressure produced during the voiceless, stop‐plosive task. The findings of reduced respiratory capacity and control in smokers may be associated with factors such as increased bronchial reactivity secondary to exposure to cigarette smoke and/or mild airway obstruction, increased airflow secondary to increased glottal gap size during phonation, and increased vocal fold mass and/or inefficiency in vocal fold closure. The findings of this study indicate that decrements in respiratory capacity and control may occur even in relatively young smokers who have only been smoking for a comparatively short time     

The role of psychoneuroimmune interactions in the pathogenesis of ligature-induced periodontal disease in Wistar rats

The aim of the present study was to determine the role of chronic stress in the pathogenesis of ligature-induced periodontal disease in rats. Fifty-three Wistar rats were randomly assigned to 4 experimental groups: 1--ligature; 2--ligature + stress; 3--stress only; 4--control. After 30 days the animals were sacrificed, blood samples were collected and histological sections were made for histometric analysis. The stress parameters evaluated were weight of thymus, spleen, adrenal glands and plasma glucocorticoid levels. Analysis of adrenal glands showed statistically significant differences between stressed and non-stressed groups (one-way ANOVA, p < 0.05). Plasma glucocorticoid levels were higher in Group 3 and lower in Group 2 (81.1 nmol/I versus 62.5 nmol/l, p < 0.05). Histometric measurements from the bone crest and from the first attached fiber were taken for all groups and for Groups 1 and 2 for the sites with and without ligatures. The ligature sites always displayed higher mean values than non-ligated sites (paired sample t test, p < 0.05). No statistically significant differences were observed between Groups 1 and 2 with regard to the ligated sites. However, differences were observed between Groups 1 and 2 in histometric bone levels in the non-ligated sites (mean values of 0.81 and 0.55 mm, respectively, p < 0.05). It may be concluded that stress can have a possible role in the activation of the hypothalamus-pituitary-adrenal (HPA) axis, with different levels of glucocorticoid release.     

Novel isomannide-based peptide mimetics containing a tartaric acid backbone as serine protease inhibitors

Hepatitis C viral infection is a cause of chronic liver disease, and current therapies are only effective in 50 % of patients. Serine proteases, which are present in both hepatitis C virus (HCV) and the dengue virus, are the most studied class of proteolytic enzymes and are the primary targets for drug development in this field. In this paper, we describe the synthesis of a novel class of isomannide-based peptide mimetic compounds based on a tartaric acid backbone. Our data showed that substitutions at position 168 (D168A) and 170 (V170A) conferred low-level resistance against compound 5a3, whereas substitutions at position 155 (R155K) and 156 (A156V) conferred no resistance. These data suggest that even though compound 5a3 is a noncompetitive inhibitor; it is able to interact with important residues located near the catalytic site. In addition, this novel compound class exhibits potent antiviral activity against variants carrying resistance mutations to boceprevir and telaprevir. Our docking studies showed important interactions, including hydrogen bonds and a π–π interaction, between compound 5a3 and residues of the allosteric site of NS3/4A. Biological and theoretical results indicate that 5a3 is a promising lead compound for the development of new drugs targeting HCV infection.     

The Brazilian Founder Mutation TP53 p.R337H is Uncommon in Portuguese Women Diagnosed with Breast Cancer

Since the first studies reporting the TP53 p.R337H mutation as founder mutation in Southern and Southeastern Brazil, there has been controversy on its origin. Preliminary analysis of a small subset of Brazilian mutation carriers revealed that the haplotype incided on a Caucasian background. The vast majority of carriers identified today reside in Brazil or, if identified in other countries, are Brazilian immigrants. To our knowledge, the only two exceptions of carriers without a recognizable link with Brazil are two European families, from Portugal and Germany. Haplotype analysis in the Portuguese family revealed the same haplotype identified in Brazilian individuals, but in the German family, a distinct haplotype was found. Knowing that a significant proportion of women with breast cancer (BC) in Southern Brazil are p.R337H carriers, we analyzed p.R337H in a Portuguese cohort of women diagnosed with this disease. Median age at diagnosis among the first 573 patients tested was 60 years and 100 (17.4%) patients had been diagnosed at or under the age of 45 years. Mutation screening failed to identify the mutation in the 573 patients tested. These results are in contrast with the mutation frequency observed in a study including 815 BC‐affected women from Brazil, in which carrier frequencies of 12.1 and 5.1% in pre‐ and postmenopausal women were observed, respectively. These findings suggest that the Brazilian founder mutation p.R337H, the most frequent germline TP53 mutation reported to date, is not a common germline alteration in Portuguese women diagnosed with BC.