Lung injury caused by occupational exposure to particles from the industrial combustion of cashew nut shells: a mice model.

Cashew nut shells (CNS) is already used in the energy matrix of some industries. However, it is necessary to know the harmful health effects generated by exposure to pollutants of its combustion, especially in the workers exposed to industrial pollutants. In addition, it is known that the incidence of asthma grows among workers in industries, and due to its previously reported biological effects of anethole, these will also be objects of the present study. We used 64 Balb/C mice, randomly divided into eight groups. Groups were sensitized and challenged with saline or ovalbumin, then subjected to intranasal instillation of 30 µg PM4.0 (occupational exposure) from the combustion of CNS or saline, and then were subsequently treated with oral anethole 300 mg/kg or 0.1% Tween 80. Our results serve as a starting point for the development of public policies for the prevention of diseases in workers that are exposed to the pollutants coming from industries.

High prevalence of methicillin resistance and PVL genes among Staphylococcus aureus isolates from the nares and skin lesions of pediatric patients with atopic dermatitis

Staphylococcus aureus is highly prevalent among patients with atopic dermatitis (AD), and this pathogen may trigger and aggravate AD lesions. The aim of this study was to determine the prevalence of S. aureus in the nares of pediatric subjects and verify the phenotypic and molecular characteristics of the isolates in pediatric patients with AD. Isolates were tested for antimicrobial susceptibility, SCCmec typing, and Panton-Valentine Leukocidin (PVL) genes. Lineages were determined by pulsed-field gel electrophoresis and multilocus sequence typing (MLST). AD severity was assessed with the Scoring Atopic Dermatitis (SCORAD) index. Among 106 patients, 90 (85%) presented S. aureus isolates in their nares, and 8 also presented the pathogen in their skin infections. Two patients had two positive lesions, making a total of 10 S. aureus isolates from skin infections. Methicillin-resistant S. aureus (MRSA) was detected in 24 (26.6%) patients, and PVL genes were identified in 21 (23.3%), including 6 (75%) of the 8 patients with skin lesions but mainly in patients with severe and moderate SCORAD values (P=0.0095). All 24 MRSA isolates were susceptible to trimethoprim/sulfamethoxazole, while 8 isolates had a minimum inhibitory concentration (MIC) to mupirocin >1024 μg/mL. High lineage diversity was found among the isolates including USA1100/ST30, USA400/ST1, USA800/ST5, ST83, ST188, ST718, ST1635, and ST2791. There was a high prevalence of MRSA and PVL genes among the isolates recovered in this study. PVL genes were found mostly among patients with severe and moderate SCORAD values. These findings can help clinicians improve the therapies and strategies for the management of pediatric patients with AD.

High prevalence of methicillin resistance and PVL genes among Staphylococcus aureus isolates from the nares and skin lesions of pediatric patients with atopic dermatitis.

Staphylococcus aureus is highly prevalent among patients with atopic dermatitis (AD), and this pathogen may trigger and aggravate AD lesions. The aim of this study was to determine the prevalence of S. aureus in the nares of pediatric subjects and verify the phenotypic and molecular characteristics of the isolates in pediatric patients with AD. Isolates were tested for antimicrobial susceptibility, SCCmec typing, and Panton-Valentine Leukocidin (PVL) genes. Lineages were determined by pulsed-field gel electrophoresis and multilocus sequence typing (MLST). AD severity was assessed with the Scoring Atopic Dermatitis (SCORAD) index. Among 106 patients, 90 (85%) presented S. aureus isolates in their nares, and 8 also presented the pathogen in their skin infections. Two patients had two positive lesions, making a total of 10 S. aureus isolates from skin infections. Methicillin-resistant S. aureus (MRSA) was detected in 24 (26.6%) patients, and PVL genes were identified in 21 (23.3%), including 6 (75%) of the 8 patients with skin lesions but mainly in patients with severe and moderate SCORAD values (P=0.0095). All 24 MRSA isolates were susceptible to trimethoprim/sulfamethoxazole, while 8 isolates had a minimum inhibitory concentration (MIC) to mupirocin >1024 µg/mL. High lineage diversity was found among the isolates including USA1100/ST30, USA400/ST1, USA800/ST5, ST83, ST188, ST718, ST1635, and ST2791. There was a high prevalence of MRSA and PVL genes among the isolates recovered in this study. PVL genes were found mostly among patients with severe and moderate SCORAD values. These findings can help clinicians improve the therapies and strategies for the management of pediatric patients with AD.

Meticillin-resistant Staphylococcus aureus: spread of specific lineages among patients in different wards at a Brazilian teaching hospital.

This study aimed to characterize meticillin-resistant Staphylococcus aureus (MRSA) lineages circulating in a Brazilian teaching hospital. MRSA isolates from nasal swabs were evaluated to assess antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec), Panton-Valentine leucocidin status, pulsed-field gel electrophoresis profile and multi-locus sequence type (MLST) analysis. Eighty-three MRSA isolates were analysed. SCCmec III (43.4%) and IV (49.4%) were predominant. ST1-IV (USA400) was more common in internal medicine (P = 0.002) whereas 'clone M' (SCCmec III) was more common in the medical and surgical intensive care unit (P = 0.004), and all isolates were ST5-IV (USA800) in dermatology (P < 0.001). These data improved the understanding of the MRSA epidemiology inside the hospital and helped to establish effective control measures.

Loss of lingual sensitivity and slightly increased size signaling schwannoma in a patient with mixed conjunctive tissue disease.

The purpose of this study was to describe an unusual case of a lingual schwannoma associated with a mixed connective tissue disease (MCTD). A case report. A lingual schwannoma with loss of lingual sensitivity and slightly increased size in an 18-year-old patient with MCTD was correctly diagnosed through a biopsy and no reoccurrence was observed one year after the surgical removal of the tumor and sensitivity returned 3 months after surgery. This case was considered uncommon, making the clinical diagnosis challenging in view of the diversity of possibilities for its differential diagnosis, thus showing the importance of a biopsy to confirm the diagnosis and long term follow up in such cases.

The first case report of non-nosocomial healthcare-associated infective endocarditis due to methicillin-resistant Staphylococcus aureus USA400 in Rio de Janeiro, Brazil.

Staphylococcus aureus is the main causal pathogen of infective endocarditis (IE), which may have distinct origins, namely, community, nosocomial, or non-nosocomial healthcare-associated (NNHCA). We report the first case of NNHCA-IE caused by methicillin-resistant S. aureus strain USA400/SCCmec IV in which the combination therapy of rifampin and vancomycin had a favorable outcome for the patient.

Implications of efavirenz for neuropsychiatry: a review.

Antiretroviral therapy has revolutionized the treatment of the human immunodeficiency virus because it has improved the clinical outcomes of patients. It is essential that these drugs cross the blood-brain barrier, since the virus is present in the central nervous system (CNS). Efavirenz passes through this barrier satisfactorily and can reduce the deleterious central effects of the human immunodeficiency virus. However, patients treated with efavirenz have been observed to experience psychiatric symptoms such as mania, depression, suicidal thoughts, psychosis, and hallucinations. The aim of this review is to describe the pharmacokinetic and pharmacodynamic properties of efavirenz and its major neuropsychiatric symptoms and the neurochemical pathways associated with these changes in the CNS. The databases Medline and Lilacs were used to search for review articles and preclinical and clinical research articles published from January 1996 to 2010. The search terms used were efavirenz, central nervous system, neuropsychiatry, neurotransmitters, adverse effects, and neurochemistry. Subject categories considered included effects on viral replication, pharmacokinetic and pharmacodynamic properties of efavirenz, and neuropsychiatric adverse effects including time course, duration, and probable mechanisms involved. The mechanisms involved in these changes include interference with cytochrome P450 enzymes, cytokines, tryptophan-2-3-dioxygenase, and brain creatine kinase.

Essential oil of croton nepetaefolius and its main constituent, 1,8-cineole, block excitability of rat sciatic nerve in vitro.

1. The effects of the essential oil of Croton nepetaefolius (EOCN) and its major constituent, 1,8-cineole, on the compound action potential (CAP) of nerve were investigated. 2. Experiments were performed in sciatic nerves dissected from Wistar rats, mounted in a moist chamber and stimulated at a frequency of 0.2 Hz, with electric pulses of 100 micros duration at 20-40 V. Evoked CAP were displayed on an oscilloscope and recorded on a computer. The CAP control parameters were as follows: peak-to-peak amplitude 8.1 +/- 0.6 mV (n = 15); conduction velocity 83.3 +/- 4.2 m/s (n = 15); chronaxie 58.0 +/- 6.8 msec (n = 6); and rheobase 2.8 +/- 0.1 V (n = 6). 3. Lower concentrations of EOCN (100 and 300 microg/mL) and 1,8-cineole (153 and 307 microg/mL; i.e. 1 and 2 mmol/L, respectively) had no significant effects on CAP control parameters throughout the entire recording period. However, at the end of 180 min exposure of the nerve to the drug, peak-to-peak amplitude was significantly (P < 0.05) reduced to 27.4 +/- 6.7 and 1.7 +/- 0.8% of control values by 500 and 1000 microg/mL EOCN, respectively (n = 6), and to 76.5 +/- 4.4, 70.0 +/- 3.9 and 14.8 +/- 4.1% of control values by 614, 920 and 1227 microg/mL (i.e. 4, 6 and 8 mmol/L) 1,8-cineole, respectively (n = 6). Regarding conduction velocity, at the end of the 180 min exposure period, this parameter was significantly reduced to 85.8 +/- 7.3 and 48.7 +/- 12.3% (n = 6) of control values by 500 and 1000 microg/mL EOCN, respectively, and to 86.4 +/- 4.5 and 76.1 +/- 5.2% (n = 6) by 920 and 1227 microg/mL 1,8-cineole, respectively. Chronaxie and rheobase were significantly increased by the higher concentrations of both EOCN and 1,8-cineole. 4. It is concluded that EOCN and its main constituent 1,8-cineole block nerve excitability in a concentration-dependent manner, an effect that was totally reversible with 1,8-cineole but not with EOCN. This suggests that other constituents of EOCN, in addition to 1,8-cineole, may contribute to the mediation of this effect of EOCN.

Roles of mechanical forces and collagen failure in the development of elastase-induced emphysema.

Emphysema causes a permanent destruction of alveolar walls leading to airspace enlargement, loss of elastic recoil, decrease in surface area for gas exchange, lung hyperexpansion, and increased work of breathing. The most accepted hypothesis of how emphysema develops is based on an imbalance of protease and antiprotease activity leading to the degradation of elastin within the fiber network of the extracellular matrix. Here we report novel roles for mechanical forces and collagen during the remodeling of lung tissue in a rat model of elastase-induced emphysema. We have developed a technique to measure the stress-strain properties of tissue sections while simultaneously visualizing the deformation of the immunofluorescently labeled elastin-collagen network. We found that in the elastase treated tissue significant remodeling leads to thickened elastin and collagen fibers and during stretching, the newly deposited elastin and collagen fibers undergo substantially larger distortions than in normal tissue. We also found that the threshold for mechanical failure of collagen, which provides mechanical stability to the normal lung, is reduced. Our results indicate that mechanical forces during breathing are capable of causing failure of the remodeled extracellular matrix at loci of stress concentrations and so contribute to the progression of emphysema.

Hysteresivity of the lung and tissue strip in the normal rat: effects of heterogeneities.

We measured lung impedance in rats in closed chest (CC), open chest (OC), and isolated lungs (IL) at four transpulmonary pressures with a optimal ventilator waveform. Data were analyzed with an homogeneous linear or an inhomogeneous linear model. Both models include tissue damping and elastance and airway inertance. The homogeneous linear model includes airway resistance (Raw), whereas the inhomogeneous linear model has a continuous distribution of Raw characterized by the mean Raw and the standard deviation of Raw (SDR). Lung mechanics were compared with tissue strip mechanics at frequencies and operating stresses comparable to those during lung impedance measurements. The hysteresivity (eta) was calculated as tissue damping/elastance. We found that 1) airway and tissue parameters were different in the IL than in the CC and OC conditions; 2) SDR was lowest in the IL; and 3) eta in IL at low transpulmonary pressure was similar to eta in the tissue strip. We conclude that eta is primarily determined by lung connective tissue, and its elevated estimates from impedance data in the CC and OC conditions are a consequence of compartment-like heterogeneity being greater in CC and OC conditions than in the IL.

Effects of collagenase and elastase on the mechanical properties of lung tissue strips.

The dynamic stiffness (H), damping coefficient (G), and harmonic distortion (k(d)) characterizing tissue nonlinearity of lung parenchymal strips from guinea pigs were assessed before and after treatment with elastase or collagenase between 0.1 and 3.74 Hz. After digestion, data were obtained both at the same mean length and at the same mean force of the strip as before digestion. At the same mean length, G and H decreased by approximately 33% after elastase and by approximately 47% after collagenase treatment. At the same mean force, G and H increased by approximately 7% after elastase and by approximately 25% after collagenase treatment. The k(d) increased more after collagenase (40%) than after elastase (20%) treatment. These findings suggest that, after digestion, the fraction of intact fibers decreases, which, at the same mean length, leads to a decrease in moduli. At the same mean force, collagen fibers operate at a higher portion of their stress-strain curve, which results in an increase in moduli. Also, G and H were coupled so that hysteresivity (G/H) did not change after treatments. However, k(d) was decoupled from elasticity and was sensitive to stretching of collagen, which may be of value in detecting structural alterations in the connective tissue of the lung.

Fluid flow through ramified structures.

We investigate the fluid flow through two-dimensional ramified structures by direct simulation of the Navier-Stokes equations. We show that for trees with n generations, the flow distribution strongly depends on the Reynolds number Re. Specifically, for a tree without loops the flow becomes highly heterogeneous at high Re. For a tree with loops, on the other hand, the flow distribution tends to be more uniform at increased Re conditions. We show that these apparently contradictory behaviors have the same origin, namely, the effect of inertia on the momentum transport in the channels of the ramified geometry. In order to simulate the propagation of the flow imbalance throughout the tree without loops, we develop a simple model that incorporates the basic fluid dynamics features of the system. For large trees, the results of the model indicate that the distribution of flow at the outlet branches can be described by a self-affine landscape. Finally, we argue that the nonuniform partitioning of flow found for the structure without loops may contribute to the morphogenesis and functioning of the bronchial tree.