Long-term stimulation of cardiac vagal preganglionic neurons reduces blood pressure in the spontaneously hypertensive rat

BACKGROUND: Arterial hypertension is associated with autonomic nervous system dysfunction. Different interventional strategies have been implemented in recent years for the reduction of sympathetic activity in patients with hypertension. However, the therapeutic benefit of increasing vagal tone in hypertensive patients remains largely unexplored. OBJECTIVE: Here, we describe the effects of long-term activation of vagal neural pathways on arterial pressure, heart rate arterial pressure variability and spontaneous baroreflex sensitivity in spontaneously hypertensive rats (SHR) and normotensive Wistar rats. METHODS: Brainstem vagal preganglionic neurons residing in the dorsal vagal motor nucleus (DVMN) were targeted with a lentiviral vector to induce the expression of an artificial G(s) protein-coupled receptor termed designer receptors exclusively activated by designer drugs (DREADD-Gs). The transduced neurons were activated daily by systemic administration of otherwise inert ligand clozapine-n-oxide. Arterial pressure measurements were recorded in conscious freely moving animals after 21 consecutive days of DVMN stimulation. RESULTS: Resting arterial pressure was significantly lower in SHRs expressing DREADD-Gs in the DVMN, compared with control SHRs expressing enhanced green fluorescent protein. No changes in arterial pressure were detected in Wistar rats expressing DREADD-Gs compared with rats expressing enhanced green fluorescent protein in the DVMN. Pharmacogenetic activation of DREADD-Gs-expressing DVMN neurons in SHRs was accompanied with increased baroreflex sensitivity and a paradoxical decrease in cardio-vagal components of heart rate and systolic arterial pressure variability in SHRs. CONCLUSION: These results suggest that long-term activation of vagal parasympathetic pathways is beneficial in restoring autonomic balance in an animal model of neurogenic hypertension and might be an effective therapeutic approach for the management of hypertension

Effect of Stocking Density and Sex on Feathering, Body Injury and Breast Meat Quality of Broiler Chikens

The experiment was conducted at the College of Veterinary Medicine and Animal Production of UNESP-Botucatu Campus to evaluate the effect of stocking densities and sex on body injuries and breast meat quality. One thousand nine hundred and fifty day-old Ross chicks were reared until 42 days of age on a randomized factorial arrangement with three stock densities (10, 13 and 16 birds/m²) and two sexes. At 28, 35 and 42 days of age, 15 birds/treatment were sampled to determine feathering percentage related to body weight and 50 birds/treatment to evaluate score feathering. At 42 days of age, all broilers were processed to evaluate body injuries and breast meat quality. Increasing stocking densities decreased feathering and increased body injuries like breast blisters, dermatitis, bruises and scratches. Breast meat yield and breast length width and depth was negatively affected (p<.05) as stocking densities increased.O experimento foi conduzido nas instalações experimentais da Faculdade de Medicina Veterinária e Zootecnia - UNESP, Campus de Botucatu, SP, Brasil, com o objetivo de avaliar o efeito da densidade de criação e do sexo sobre o empenamento, incidência de lesões na carcaça e a qualidade de carne de peito de frangos de corte. Foram utilizados 1950 pintos de corte sexados, da linhagem Ross, distribuídos em um delineamento inteiramente casualizado, com esquema fatorial com 3 densidades (10, 13 e 16 aves/m²) e dois sexos com 5 repetições, sendo que uma foi destinada exclusivamente para reserva, criados até os 42 dias de idade. Aos 28, 35 e 42 dias foram amostradas 3 aves por repetição para a determinação do empenamento através da porcentagem de penas e 10 aves para a determinação do escore de empenamento. Também aos 42 dias de idade todas as aves foram identificadas na pata com anilhas numeradas e submetidas à avaliação da incidência de lesões na pele. Foram escolhidas ao acaso 5 aves por repetição para a determinação da qualidade da carne de peito. Pode-se concluir que o aumento na densidade de criação promoveu uma diminuição na velocidade de empenamento e, conseqüentemente, uma maior incidência de lesões na carcaça. O comprimento, a largura e a espessura do peito foram menores para as aves criadas na maior densidade, e a perda de peso por cozimento foi maior para as aves criadas na maior densidade.000

Adenosine Signaling through A1 Receptors Inhibits Chemosensitive Neurons in the Retrotrapezoid Nucleus.

A subset of neurons in the retrotrapezoid nucleus (RTN) function as respiratory chemoreceptors by regulating depth and frequency of breathing in response to changes in tissue CO2/H+. The activity of chemosensitive RTN neurons is also subject to modulation by CO2/H+-dependent purinergic signaling. However, mechanisms contributing to purinergic regulation of RTN chemoreceptors are not entirely clear. Recent evidence suggests adenosine inhibits RTN chemoreception in vivo by activation of A1 receptors. The goal of this study was to characterize effects of adenosine on chemosensitive RTN neurons and identify intrinsic and synaptic mechanisms underlying this response. Cell-attached recordings from RTN chemoreceptors in slices from rat or wild-type mouse pups (mixed sex) show that exposure to adenosine (1 µM) inhibits chemoreceptor activity by an A1 receptor-dependent mechanism. However, exposure to a selective A1 receptor antagonist (8-cyclopentyl-1,3-dipropylxanthine, DPCPX; 30 nM) alone did not potentiate CO2/H+-stimulated activity, suggesting activation of A1 receptors does not limit chemoreceptor activity under these reduced conditions. Whole-cell voltage-clamp from chemosensitive RTN neurons shows that exposure to adenosine activated an inward rectifying K+ conductance, and at the network level, adenosine preferentially decreased frequency of EPSCs but not IPSCs. These results show that adenosine activation of A1 receptors inhibits chemosensitive RTN neurons by direct activation of a G-protein-regulated inward-rectifier K+ (GIRK)-like conductance, and presynaptically, by suppression of excitatory synaptic input to chemoreceptors

Lobar pneumonia caused by Ralstonia pickettii in a sixty-five-year-old Han Chinese man: a case report

<p>Abstract</p> <p>Introduction</p> <p><it>Ralstonia pickettii </it>is a gram-negative, oxidase-positive bacillus and is an emerging pathogen found in infections described in hospital settings. The cases reported in the literature mostly are nosocomial infections due to contaminated blood products, sterile water, saline, treatment fluids and venous catheters. Human infection unrelated to contaminated solutions is rare. We report a case of lobar pneumonia and pulmonary abscess caused by <it>Ralstonia pickettii </it>in an older patient.</p> <p>Case presentation</p> <p>A sixty-five-year old Han Chinese man presented having had cough, expectoration, chest pain and fever lasting for twenty days. His medical history was notable for hypertension over the previous ten years, and the habit of smoking for forty years. A thoracic computed tomography scan supported the diagnosis of right-sided lobar pneumonia. A lung biopsy was done and pathological analysis confirmed lobar pneumonia. Two lung biopsy specimens from separate sites grew <it>Ralstonia pickettii</it>. After six days, a repeat thoracic scan revealed a right-sided abscess. A thoracentesis was performed and the purulent fluid grew <it>Ralstonia pickettii</it>. The chest tube remained inserted to rinse the cavity with sterile sodium chloride. He received an antibiotic course of intravenous cefoperazone sodium-sulbactam sodium for eighteen days and imipenem-cilastatin for twelve days. A repeat chest X-ray revealed resolution of the pulmonary abscess and improvement of pneumonia. He remained afebrile and free of respiratory symptoms after treatments.</p> <p>Conclusion</p> <p>This case demonstrates a <it>Ralstonia pickettii </it>infection in the absence of an obvious nosocomial source. It is possible that such cases will become common in the future. Therefore, further studies are needed to evaluate its sensitivity to common antibiotics.</p

A Virulent Wolbachia Infection Decreases the Viability of the Dengue Vector Aedes aegypti during Periods of Embryonic Quiescence

A new approach for dengue control has been proposed that relies on life-shortening strains of the obligate intracellular bacterium Wolbachia pipientis to modify mosquito population age structure and reduce pathogen transmission. Previously we reported the stable transinfection of the major dengue vector Aedes aegypti with a life-shortening Wolbachia strain (wMelPop-CLA) from the vinegar fly Drosophila melanogaster. Here, we report a further characterization of the phenotypic effects of this virulent Wolbachia infection on several life-history traits of Ae. aegypti. Minor costs of wMelPop-CLA infection for pre-imaginal survivorship, development and adult size were found. However, we discovered that the wMelPop-CLA infection dramatically decreased the viability of desiccated Ae. aegypti eggs over time. Similarly, the reproductive fitness of wMelPop-CLA infected Ae. aegypti females declined with age. These results reveal a general pattern associated with wMelPop-CLA induced pathogenesis in this mosquito species, where host fitness costs increase during aging of both immature and adult life-history stages. In addition to influencing the invasion dynamics of this particular Wolbachia strain, we suggest that the negative impact of wMelPop-CLA on embryonic quiescence may have applied utility as a tool to reduce mosquito population size in regions with pronounced dry seasons or in regions that experience cool winters

A Secure Semi-Field System for the Study of Aedes aegypti

Novel vector control strategies require validation in the field before they can be widely accepted. Semi-field system (SFS) containment facilities are an intermediate step between laboratory and field trials that offer a safe, controlled environment that replicates field conditions. We developed a SFS laboratory and cage complex that simulates an urban house and yard, which is the primary habitat for Aedes aegypti, the mosquito vector of dengue in Cairns Australia. The SFS consists of a Quarantine Insectary Level-2 (QIC-2) laboratory, containing 3 constant temperature rooms, that is connected to two QIS-2 cages for housing released mosquitoes. Each cage contains the understory of a “Queenslander” timber house and associated yard. An automated air conditioning system keeps temperature and humidity to within 1°C and 5% RH of ambient conditions, respectively. Survival of released A. aegypti was high, especially for females. We are currently using the SFS to investigate the invasion of strains of Wolbachia within populations of A. aegypti