The nucleus of the solitary tract and the coordination of respiratory and sympathetic activities

It is well known that breathing introduces rhythmical oscillations in the heart rate and arterial pressure levels. Sympathetic oscillations coupled to the respiratory activity have been suggested as an important homeostatic mechanism optimizing tissue perfusion and blood gas uptake/delivery. This respiratory-sympathetic coupling is strengthened in conditions of blood gas challenges (hypoxia and hypercapnia) as a result of the synchronized activation of brainstem respiratory and sympathetic neurons, culminating with the emergence of entrained cardiovascular and respiratory reflex responses. Studies have proposed that the ventrolateral region of the medulla oblongata is a major site of synaptic interaction between respiratory and sympathetic neurons. However, other brainstem regions also play a relevant role in the patterning of respiratory and sympathetic motor outputs. Recent findings suggest that the neurons of the nucleus of the solitary tract (NTS), in the dorsal medulla, are essential for the processing and coordination of respiratory and sympathetic responses to hypoxia. The NTS is the first synaptic station of the cardiorespiratory afferent inputs, including peripheral chemoreceptors, baroreceptors and pulmonary stretch receptors. The synaptic profile of the NTS neurons receiving the excitatory drive from afferent inputs is complex and involves distinct neurotransmitters, including glutamate, ATP and acetylcholine. In the present review we discuss the role of the NTS circuitry in coordinating sympathetic and respiratory reflex responses. We also analyze the neuroplasticity of NTS neurons and their contribution for the development of cardiorespiratory dysfunctions, as observed in neurogenic hypertension, obstructive sleep apnea and metabolic disorders

EDTA and Taurolidine Affect Pseudomonas aeruginosa Virulence In Vitro-Impairment of Secretory Profile and Biofilm Production onto Peritoneal Dialysis Catheters

Peritoneal catheter-associated biofilm infection is reported to be the main cause of refractory peritonitis in peritoneal dialysis patients. The application of antimicrobial lock therapy, based on results on central venous catheters, may be a promising option for treatment of biofilm-harboring peritoneal catheters. This study investigated the effects of two lock solutions, EDTA and taurolidine, on an in vitro model of Pseudomonas aeruginosa biofilm-related peritoneal catheter infection. Silicone peritoneal catheters were incubated for 24 h with a bioluminescent strain of P. aeruginosa. Then, serial dilutions of taurolidine and/or EDTA were applied (for 24 h) once or twice onto the contaminated catheters, and P. aeruginosa viability/persistence were evaluated in real time up to 120 h using a Fluoroskan reader. On selected supernatants, high-performance liquid chromatography mass spectrometry (HPLC-MS) analysis was performed to measure the production of autoinducers (AI), phenazines, and pyocyianines. Taurolidine alone or in combination with EDTA caused a significant decrease of bacterial load and biofilm persistence on the contaminated catheters. The treatment did not lead to the sterilization of the devices, yet it resulted in a substantial destructuration of the catheter-associated P. aeruginosa biofilm. HPLC-MS analysis showed that the treatment of biofilm-harboring catheters with taurolidine and EDTA also affected the secretory activity of the pathogen. EDTA and taurolidine affect P. aeruginosa biofilm produced on peritoneal catheters and profoundly compromise the microbial secretory profile. Future studies are needed to establish whether such lock solutions can be used to render peritoneal catheterrelated infections more susceptible to antibiotic treatment

Efficacy of a Copper-Calcium-Hydroxide Solution in Reducing Microbial Plaque on Orthodontic Clear Aligners: A Case Report

The aim of this study was to investigate the ability of a copper-calcium-hydroxide-based compound to remove microbial plaque naturally produced onto orthodontic clear aligners. A commercially available dental paste, named Cupral, based on copper-calcium-hydroxide, was used. A healthy volunteer (female, 32 years old), undergoing orthodontic treatment with thermoplastic clear aligners was enrolled. By conventional/confocal microscopy and colony-forming unit (CFU) assay, 2-week used aligners were examined for microbial plaque, prior and following exposure to Cupral. Confocal microscopy revealed abundant plaque irregularly distributed onto the aligner surface. Following Cupral treatment, a drastic decrease occurred in plaque thickness and matrix presence. As assessed by the CFU assay, total microbial load approached 10 9 CFUs/aligner, with slight differences in aerobiosis and anaerobiosis culture conditions; six macroscopically different types of colonies were detected and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Following Cupral treatment, microbial load dropped to undetectable levels, irrespectively of the conditions considered. Exposure of clear aligners to Cupral results in the elimination of contaminating microorganisms; the antimicrobial activity is retained up to 1.25% concentration. Overall, our data describe a novel use of Cupral, a copper-calcium-hydroxide-based compound, in daily hygiene practices with promising results

Poder de discriminação de genótipos e representatividade de locais utilizados na avaliação de arroz de terras altas.

Neste trabalho foram utilizados dados do caráter produção de grãos provenientes de dezoito ensaios de Valor de Cultivo e Uso, conduzidos pelo programa de melhoramento de arroz de terras altas da Embrapa Arroz e Feijão, período-safra 2009/10. O objetivo foi identificar o local de teste que apresente, simultaneamente, maior poder de discriminação dos genótipos para esse caráter e represente mais adequadamente os demais locais de avaliação.Pôster - pós-graduação

Real-time monitoring of Pseudomonas aeruginosa biofilm formation on endotracheal tubes in vitro

BACKGROUND: Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for both acute and chronic infections in humans. In particular, its ability to form biofilm, on biotic and abiotic surfaces, makes it particularly resistant to host's immune defenses and current antibiotic therapies as well. Innovative antimicrobial materials, like hydrogel, silver salts or nanoparticles have been used to cover new generation catheters with promising results. Nevertheless, biofilm remains a major health problem. For instance, biofilm produced onto endotracheal tubes (ETT) of ventilated patients plays a relevant role in the onset of ventilation-associated pneumonia. Most of our knowledge on Pseudomonas aeruginosa biofilm derives from in vitro studies carried out on abiotic surfaces, such as polystyrene microplates or plastic materials used for ETT manufacturing. However, these approaches often provide underestimated results since other parameters, in addition to bacterial features (i.e. shape and material composition of ETT) might strongly influence biofilm formation. RESULTS: We used an already established biofilm development assay on medically-relevant foreign devices (CVC catheters) by a stably transformed bioluminescent (BLI)-Pseudomonas aeruginosa strain, in order to follow up biofilm formation on ETT by bioluminescence detection. Our results demonstrated that it is possible: i) to monitor BLI-Pseudomonas aeruginosa biofilm development on ETT pieces in real-time, ii) to evaluate the three-dimensional structure of biofilm directly on ETT, iii) to assess metabolic behavior and the production of microbial virulence traits of bacteria embedded on ETT-biofilm. CONCLUSIONS: Overall, we were able to standardize a rapid and easy-to-perform in vitro model for real-time monitoring Pseudomonas aeruginosa biofilm formation directly onto ETT pieces, taking into account not only microbial factors, but also ETT shape and material. Our study provides a rapid method for future screening and validation of novel antimicrobial drugs as well as for the evaluation of novel biomaterials employed in the production of new classes of ETT

Pomegranate extract affects fungal biofilm production: consumption of phenolic compounds and alteration of fungal autoinducers release

Candida albicans expresses numerous virulence factors that contribute to pathogenesis, including its dimorphic transition and even biofilm formation, through the release of specific quorum sensing molecules, such as the autoinducers (AI) tyrosol and farnesol. In particular, once organized as biofilm, Candida cells can elude conventional antifungal therapies and the host’s immune defenses as well. Accordingly, biofilm-associated infections become a major clinical challenge underlining the need of innovative antimicrobial approaches. The aim of this in vitro study was to assess the effects of pomegranate peel extract (PomeGr) on C. albicans growth and biofilm formation; in addition, the release of tyrosol and farnesol was investigated. The phenolic profile of PomeGr was assessed by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) analysis before and after exposure to C. albicans. Here, we showed that fungal growth, biofilm formation and AI release were altered by PomeGr treatment. Moreover, the phenolic content of PomeGr was substantially hampered upon exposure to fungal cells; particularly pedunculagin, punicalin, punicalagin, granatin, di-(HHDP-galloyl-hexoside)-pentoside and their isomers as well as ellagic acid–hexoside appeared highly consumed, suggesting their role as bioactive molecules against Candida. Overall, these new insights on the anti-Candida properties of PomeGr and its potential mechanisms of action may represent a relevant step in the design of novel therapeutic approaches against fungal infections

Role of the (Mn)superoxide dismutase of Enterococcus faecalis in the in vitro interaction with microglia

Enterococcus faecalis is a significant human pathogen worldwide and is responsible for severenosocomial and community-acquired infections. Although enterococcal meningitis is rare,mortality is considerable, reaching 21 %. Nevertheless, the pathogenetic mechanisms of thisinfection remain poorly understood, even though the ability of E. faecalis to avoid or survivephagocytic attack in vivo may be very important during the infection process. We previouslyshowed that the manganese-cofactored superoxide dismutase (MnSOD) SodA of E. faecalis wasimplicated in oxidative stress responses and, interestingly, in the survival within mouse peritonealmacrophages using an in vivo\u2013in vitro infection model. In the present study, we investigated therole of MnSOD in the interaction of E. faecalis with microglia, the brain-resident macrophages. Byusing an in vitro infection model, murine microglial cells were challenged in parallel with the wildtypestrain JH2-2 and its isogenic sodA deletion mutant. While both strains were phagocytosedby microglia efficiently and to a similar extent, the DsodA mutant was found to be significantlymore susceptible to microglial killing than JH2-2, as assessed by the antimicrobial protectionassay. In addition, a significantly higher percentage of acidic DsodA-containing phagosomes wasfound and these also underwent enhanced maturation as determined by the expression ofendolysosomal markers. In conclusion, these results show that the MnSOD of E. faecaliscontributes to survival of the bacterium in microglial cells by influencing their antimicrobial activity,and this could even be important for intracellular killing in neutrophils and thus for E. faecalispathogenesis

Estabelecimento da leguminosa forrageira Estilosantes Campo Grande em condição de sombreamento.

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