Control of mechanical pain hypersensitivity in mice through ligand-targeted photoablation of TrkB-positive sensory neurons

Mechanical allodynia is a major symptom of neuropathic pain whereby innocuous touch evokes severe pain. Here we identify a population of peripheral sensory neurons expressing TrkB that are both necessary and sufficient for producing pain from light touch after nerve injury in mice. Mice in which TrkB-Cre-expressing neurons are ablated are less sensitive to the lightest touch under basal conditions, and fail to develop mechanical allodynia in a model of neuropathic pain. Moreover, selective optogenetic activation of these neurons after nerve injury evokes marked nociceptive behavior. Using a phototherapeutic approach based upon BDNF, the ligand for TrkB, we perform molecule-guided laser ablation of these neurons and achieve long-term retraction of TrkB-positive neurons from the skin and pronounced reversal of mechanical allodynia across multiple types of neuropathic pain. Thus we identify the peripheral neurons which transmit pain from light touch and uncover a novel pharmacological strategy for its treatment

A Cysteine Protease Is Critical for Babesia spp. Transmission in Haemaphysalis Ticks

Vector ticks possess a unique system that enables them to digest large amounts of host blood and to transmit various animal and human pathogens, suggesting the existence of evolutionally acquired proteolytic mechanisms. We report here the molecular and reverse genetic characterization of a multifunctional cysteine protease, longipain, from the babesial parasite vector tick Haemaphysalis longicornis. Longipain shares structural similarity with papain-family cysteine proteases obtained from invertebrates and vertebrates. Endogenous longipain was mainly expressed in the midgut epithelium and was specifically localized at lysosomal vacuoles and possibly released into the lumen. Its expression was up-regulated by host blood feeding. Enzymatic functional assays using in vitro and in vivo substrates revealed that longipain hydrolysis occurs over a broad range of pH and temperature. Haemoparasiticidal assays showed that longipain dose-dependently killed tick-borne Babesia parasites, and its babesiacidal effect occurred via specific adherence to the parasite membranes. Disruption of endogenous longipain by RNA interference revealed that longipain is involved in the digestion of the host blood meal. In addition, the knockdown ticks contained an increased number of parasites, suggesting that longipain exerts a killing effect against the midgut-stage Babesia parasites in ticks. Our results suggest that longipain is essential for tick survival, and may have a role in controlling the transmission of tick-transmittable Babesia parasites

Análise da postura craniocervical de crianças respiradoras bucais após tratamento postural em bola suíça

The study aimed to evaluate the craniocervical posture of mouth breathing children after postural treatment on swiss ball. Twelve mouth breathing children were undergone to a postural reeducation protocol through stretching and strengthening exercises on swiss ball, diaphragmatic stimulation and stretching of the inspiratory accessory muscles. Craniocervical posture was evaluated through biophotogrammetry analysis. Forward head position was measured through an angle formed by the points in the tragus and in the spinous process of the seventh cervical vertebra with a horizontal line. Cervical column curvature was taken by the horizontal distance from a vertical line passing through the thoracic kyphosis apex to the point of the greatest cervical curvature concavity. Pictures were taken before and after ten treatment sessions. The normality of the variables was tested by Shapiro-Wilk test and the Student's t -test was used to determine differences in variables between assessments. It was considered a significance level of 5% (pO estudo teve como objetivo avaliar a postura craniocervical de crianças respiradoras bucais após tratamento postural em bola suíça. Doze crianças respiradoras bucais foram submetidas a um protocolo de reeducação postural constituído por exercícios de alongamento e fortalecimento muscular sobre a bola suíça, estimulação diafragmática e alongamento dos músculos acessórios da inspiração. A postura craniocervical foi avaliada através da análise biofotogramétrica. A posição da anteriorização da cabeça foi aferida por meio do ângulo formado pelos pontos localizados no tragus direito e no processo espinhoso da sétima vértebra cervical com a linha horizontal. A curvatura cervical foi avaliada pela distância horizontal de uma linha vertical tangenciando o ápice da cifose torácica e o ponto de maior concavidade da curvatura cervical. As fotografias foram obtidas antes e após dez atendimentos. A normalidade das variáveis foi verificada a partir do teste Shapiro-Wilk. Para as comparações entre as médias foi utilizado o teste t de Student para amostras dependentes admitindo-se nível de significância de 5% (

Circulating Pneumolysin Is a Potent Inducer of Cardiac Injury during Pneumococcal Infection

Streptococcus pneumoniae accounts for more deaths worldwide than any other single pathogen through diverse disease manifestations including pneumonia, sepsis and meningitis. Life-threatening acute cardiac complications are more common in pneumococcal infection compared to other bacterial infections. Distinctively, these arise despite effective antibiotic therapy. Here, we describe a novel mechanism of myocardial injury, which is triggered and sustained by circulating pneumolysin (PLY). Using a mouse model of invasive pneumococcal disease (IPD), we demonstrate that wild type PLY-expressing pneumococci but not PLY-deficient mutants induced elevation of circulating cardiac troponins (cTns), well-recognized biomarkers of cardiac injury. Furthermore, elevated cTn levels linearly correlated with pneumococcal blood counts (r=0.688, p=0.001) and levels were significantly higher in non-surviving than in surviving mice. These cTn levels were significantly reduced by administration of PLY-sequestering liposomes. Intravenous injection of purified PLY, but not a non-pore forming mutant (PdB), induced substantial increase in cardiac troponins to suggest that the pore-forming activity of circulating PLY is essential for myocardial injury in vivo. Purified PLY and PLY-expressing pneumococci also caused myocardial inflammatory changes but apoptosis was not detected. Exposure of cultured cardiomyocytes to PLY-expressing pneumococci caused dose-dependent cardiomyocyte contractile dysfunction and death, which was exacerbated by further PLY release following antibiotic treatment. We found that high PLY doses induced extensive cardiomyocyte lysis, but more interestingly, sub-lytic PLY concentrations triggered profound calcium influx and overload with subsequent membrane depolarization and progressive reduction in intracellular calcium transient amplitude, a key determinant of contractile force. This was coupled to activation of signalling pathways commonly associated with cardiac dysfunction in clinical and experimental sepsis and ultimately resulted in depressed cardiomyocyte contractile performance along with rhythm disturbance. Our study proposes a detailed molecular mechanism of pneumococcal toxin-induced cardiac injury and highlights the major translational potential of targeting circulating PLY to protect against cardiac complications during pneumococcal infections

Reliability intra-and inter-examiner of the head postural assessment by computerized photogrammetry

Scientific articles about reliability of photogrammetry for cervical spine posture evaluation are infrequent. The aim of the present investigation is to verify intra-and inter-examiner reliability of the computerized photogrammetry method for head postural evaluation in lateral view. Twenty-five young women, between 20 and 30 years old, were positioned seated in an upright position and photographed in lateral view. The photographs were imported to Corel Draw X13 program for postural evaluation by computerized photogrammetry. Analyses of intra-and inter-examiner reliability were performed for the angles: condyle-acromion (ACA), menton-sternum (AME) and Frankfurt (AF). The photogrammetry was performed by two examiners: EA and EB. For intra-examiner analyses, EA assessed the pictures twice (A1 and A2) for the same angles within 3 months. For the inter-examiner analyses, EB performed the photogrammetry for the same angles (B1) in order to compare with the data from EA. Using the interclass correlation coefficient (ICC) we observed an excellent correlation in the intra-examiner analysis (A1 and A2) for the angles: ACA and AME (both with ICC=1.0); and AF (ICC=0.78). For the inter-examiner analyses between A1 and B1, it was observed: ACA (ICC=0.24), AME (ICC=0.26) and AF (ICC=0.00). For the comparison between A2 and B1, the ICC values were: 0.23; 0.27 and 0.00, respectively for ACA, AME and AF, classified as weak correlations. In conclusion, the photogrammetry is reliable when performed by the same examiner. The inter-examiner assess showed low reliability, what could have been compromised by the reduced experience of the EB in applying the method