Pathogenesis of pleural infection

The pleura responds to the presence of infecting organisms with a vigorous inflammatory response associated with an exudation of white blood cells and proteins. The development and outcome of pleural infections is a function of a balance between the virulence of the invading microorganism and the immune reaction involving professional immune cells as well as the pleural mesothelial cells. Most commonly, pleural infection occurs after invasion through the lung parenchyma and a breach in the viscera pleura resulting in the formation of a parapneumonic process. Upon infection, the microorganisms are recognized by the pleural mesothelial cell, which remains the first line of defence. Pleural responses to infection include those of innate immunity as well as adaptive or acquired immunity. Innate and acquired immune responses are closely linked. In this review, we discuss the different virulence factors that allow microorganisms to infect the pleura and the role of the pleural mesothelial cells in bridging the innate and acquired immune responses.     

Reduction in False-Positive Aspergillus Serum Galactomannan Enzyme Immunoassay Results Associated with Use of Piperacillin-Tazobactam in the United States

Piperacillin-tazobactam (PTZ) is known to cause false-positive results in the Platelia Aspergillus enzyme-linked immunoassay (EIA), due to contamination with galactomannan (GM). We tested 32 lots of PTZ and 27 serum specimens from patients receiving PTZ. GM was not detected in the lots of PTZ; one serum specimen (3.7%) was positive. PTZ formulations commonly used in the United States today appear to be a rare cause for false-positive GM results.     

Fabrication of PLA/PCL/Graphene Nanoplatelet (GNP) Electrically Conductive Circuit Using the Fused Filament Fabrication (FFF) 3D Printing Technique

For the purpose of fabricating electrically conductive composites via the fused filament fabrication (FFF) technique whose properties were compared with injection-moulded properties, poly(lactic acid) (PLA) and polycaprolactone (PCL) were mixed with different contents of graphene nanoplatelets (GNP). The wettability, morphological, rheological, thermal, mechanical, and electrical properties of the 3D-printed samples were investigated. The microstructural images showed the selective localization of the GNPs in the PCL nodules that are dispersed in the PLA phase. The electrical resistivity results using the four-probes method revealed that the injection-moulded samples are insulators, whereas the 3D-printed samples featuring the same graphene content are semiconductors. Varying the printing raster angles also exerted an influence on the electrical conductivity results. The electrical percolation threshold was found to be lower than 15 wt.%, whereas the rheological percolation threshold was found to be lower than 10 wt.%. Furthermore, the 20 wt.% and 25 wt.% GNP composites were able to connect an electrical circuit. An increase in the Young’s modulus was shown with the percentage of graphene. As a result, this work exhibited the potential of the FFF technique to fabricate biodegradable electrically conductive PLA-PCL-GNP composites that can be applicable in the electronic domain.     

Compensatory mechanisms affect sensorimotor integration during ongoing vocal motor acts in marmoset monkeys

Any transmission of vocal signals faces the challenge of acoustic interferences such as heavy rain, wind, animal or urban sounds. Consequently, several mechanisms and strategies have evolved to optimize signal‐to‐noise ratio. Examples to increase detectability are the Lombard effect, an involuntary rise in call amplitude in response to masking ambient noise, which is often associated with other vocal changes such as call frequency and duration, as well as the animals’ capability of limiting calling to periods where noise perturbation is absent. Previous studies revealed vocal flexibility and various audio‐vocal integration mechanisms in marmoset monkeys. Using acoustic perturbation triggered by vocal behaviour, we investigated whether marmosets are capable of exhibiting changes in call structure when perturbing noise starts after call onset or whether such effects only occur if noise perturbation starts prior to call onset. We show that marmosets are capable of rapidly modulating call amplitude and frequency in response to such noise perturbation. Vocalizations swiftly increased call frequency after noise onset indicating a rapid effect of perturbing noise on vocal motor production. Call amplitudes were also affected. Interestingly, however, the marmosets did not exhibit the Lombard effect as previously reported but decreased call intensity in response to noise. Our findings indicate that marmosets possess a general avoidance strategy to call in the presence of ambient noise and suggest that these animals are capable of counteracting a previously thought involuntary audio‐vocal mechanism, the Lombard effect. These findings will pave the way to investigate the underlying audio‐vocal integration mechanisms explaining these behaviours.     

ELECTRON MICROSCOPIC SUB-CLASSIFICATION OF SMALL CELL CARCINOMA OF THE LUNG

An electron microscopic study of 28 small cell carcinomas of the lung is presented. Cytoplasmic secretory granules, characteristic of endocrine cells of the human foetal lung were observed in a variable number of tumor cells. Two groups of tumors could be distinguished based on the morphology of the cytoplasmic secretory granules. Twenty-three tumors showed cells with granules resembling type 1 or P₁ cells of the human fetal lung, and 5 tumors with granules resembling type 3 cells of the human fetal lung. No relationship was found between the light microscopic WHO classification of small cell carcinoma of the lung and the results obtained by electron microscopy. Increased serum calcitonin as well as inappropriate ADH secretion may be correlated with one of the two types of small cell carcinoma, but further investigations are needed.     

Allergenicity and immunogenicity of the major mugwort pollen allergen Art v 1 chemically modified by acetylation

Background Treating allergies with modified allergens is an approach to make the treatment safer and more efficient. Art v 1 is the most prominent allergen of mugwort pollen and a significant cause of hayfever around Europe. The aim of this study was to reduce the allergenicity of Art v 1 by acetylation, and to investigate the capacity of the modified protein to generate blocking antibodies.
Methods The reduction of allergenicity of Art v 1 following acetylation was monitored by immunoblot, ELISA inhibition using a pool of sera from mugwort pollen allergic patients, basophil activation assay and by skin prick testing of mugwort-allergic patients. Rabbits were immunized against Art v 1 and acetylated Art v 1 (acArt v 1) and the rabbit antisera were tested for their capacity to block human IgE binding in ELISA. Human T cell proliferation against Art v 1 and acArt v 1 was examined in peripheral blood mononuclear cells (PBMCs) of mugwort pollen allergic patients and cytokine release in PBMC cultures was monitored.
Results Acetylation of Art v 1 gave a derivative of reduced allergenicity in the in vitro and ex vivo tests applied. The skin test reactivity to acArt v 1 was significantly reduced in 19 patients when compared with the reactivity to Art v 1. Rabbit antibodies to acArt v 1 and Art v 1 showed similar capacity to block human IgE binding to Art v 1 in inhibition ELISA. Both proteins were able to induce proliferation of PBMCs and CD3/CD4⁺ cells of mugwort-allergic patients. Release of IL-5 was significantly reduced in cultures stimulated with acArt v 1.
Conclusions Art v 1 modified by acetylation had a significantly reduced allergenicity in vitro and in vivo , while its immunogenicity was retained. Modification of allergens by acetylation could be a new strategy for allergen-specific immunotherapy.     

Usefulness of Live/Real Time Three‐Dimensional Transthoracic Echocardiography in Evaluation of Prosthetic Valve Function

We studied 31 patients with prosthetic valves (PVs) using two‐dimensional and three‐dimensional transthorathic echocardiography (2DTTE and 3DTTE, respectively) in order to determine whether 3DTTE provides an incremental value on top of 2DTTE in the evaluation of these patients. With 3DTTE both leaflets of the St. Jude mechanical PV can be visualized simultaneously, thereby increasing the diagnostic confidence in excluding valvular abnormalities and overcoming the well‐known limitations of 2DTTE in the examination of PVs, which heavily relies on Doppler. Three‐dimensional transthorathic echocardiography provides a more comprehensive evaluation of PV regurgitation than 2DTTE with its ability to more precisely quantify PV regurgitation, in determining the mechanism causing regurgitation, and in localizing the regurgitant defect. Furthermore, 3DTTE is superior in identifying, quantifying, and localizing PV thrombi and vegetations, in addition to the unique feature of providing a look inside mass lesions by serial sectioning. These preliminary results suggest the superiority of 3DTTE over 2DTTE in the evaluation of PVs and that it provides incremental knowledge to the echocardiographer. (ECHOCARDIOGRAPHY, Volume 26, November 2009)