Surfactant protein D (SP-D) plays important roles in innate immunity

The value of ultrasound techniques in examination of the pleurae and lungs has been underestimated over recent decades. One explanation for this is the assumption that the ventilated lungs and the bones of the rib cage constitute impermeable obstacles to ultrasound. However, a variety of pathologies of the chest wall, pleurae and lungs result in altered tissue composition, providing substantially increased access and visibility for ultrasound examination. It is a great benefit that the pleurae and lungs can be non-invasively imaged repeatedly without discomfort or radiation exposure for the patient. Ultrasound is thus particularly valuable in follow-up of disease, differential diagnosis and detection of complications. Diagnostic and therapeutic interventions in patients with pathologic pleural and pulmonary findings can tolerably be performed under real-time ultrasound guidance. In this article, an updated overview is given presenting not only the benefits and indications, but also the limitations of pleural and pulmonary ultrasound.

EUS-elastography of the pancreas has the potential to obtain some complementary information that would improve tissue characterization. Its clinical utility, however, remains questionable, and it seems unlikely that the information provided will obviate the necessity of obtaining tissue samples for confirmation of a final pathologic diagnosis.

Activated neutrophils use myeloperoxidase (MPO) to generate an array of potent toxic oxidants. In the current studies we used genetically altered mice deficient in MPO to investigate the role of the enzyme in host defense against the Gram-negative bacterium Klebsiella pneumoniae, an important human pathogen. For comparison, we used mice deficient in the antimicrobial molecule, neutrophil elastase (NE). When challenged i.p., mice deficient in either MPO or NE were markedly more susceptible to bacterial infection and death. In vitro studies suggested that MPO impairs the morphology of bacteria in a distinctive way. Of importance, our in vitro studies found that MPO mediated oxidative inactivation of NE, an enzyme that has been widely implicated in the pathogenesis of various tissue-destructive diseases. This pathway of oxidative inactivation may be physiologically relevant, because activated neutrophils isolated from MPO-deficient mice exhibited increased elastase activity. Our observations provide strong evidence that MPO, like NE, is a key player in the killing of K. pneumoniae bacteria. They also suggest that MPO may modulate NE to protect the host from the tissue-degrading activity of this proteinase.

According to the widely accepted view, neutrophil elastase (NE), a neutrophil-specific serine protease, is a major contributor to Pseudomonas aeruginosa infection-associated host tissue inflammation and damage, which in severe cases can lead to death. Herein, we provide for the first time compelling evidence that the host rather employs NE to protect itself against P. aeruginosa infection. Using a clinically relevant model of pneumonia, targeted deficiency in NE increased the susceptibility of mice to P. aeruginosa. We found that NE was required for maximal intracellular killing of P. aeruginosa by neutrophils. In investigating the mechanism of NE-mediated killing of P. aeruginosa, we found that NE degraded the major outer membrane protein F, a protein with important functions, including porin activity, maintenance of structural integrity, and sensing of host immune system activation. Consistent with this, the use of an isogenic mutant deficient in outer membrane protein F negated the role of NE in host defense against P. aeruginosa infection.

Endoscopic ultrasound (EUS) elastography distinguishes tissues on the basis of their specific consistency. The preoperative diagnosis of autoimmune pancreatitis (AIP) is of the utmost importance in order to avoid surgery. The aim of this prospective evaluation of five patients was to investigate the role of this new technique in the characterization of mass lesions caused by AIP, with histology as the gold standard. All five patients with AIP presented with a characteristic stiff elastographic pattern not only of the mass lesion but also of the surrounding pancreatic parenchyma, which was not found in 17 patients with ductal adenocarcinoma and 10 healthy subjects. EUS elastography of the pancreas shows a typical and unique finding with homogenous stiffness of the whole organ, and this distinguishes AIP from the circumscribed mass lesion in ductal adenocarcinoma.

To reach the sites of inflammation, neutrophils traverse the endothelium, its underlying basement membrane, and other barriers depending on the localization of the insulting agent. Whether neutrophil elastase (NE) plays a role in neutrophil recruitment to inflamed sites is still debatable. By exploiting mice deficient in NE (NE(-/-)), we sought to address this dilemma. We recruited neutrophils to the lungs or the peritoneum of wild-type (WT) or NE(-/-) mice by intranasal or intraperitoneal challenge with Pseudomonas aeruginosa or its lipopolysaccharide. At designated times post-inoculation (0, 4, 24, and 48 h), groups of mice were killed to assess changes in leukocyte counts and inflammatory responses. NE(-/-) and WT mice had normal circulating leukocyte numbers including neutrophils and changes in the hemograms in the setting of acute inflammation were indistinguishable. Analyses of lung tissues or fluids from the lungs and peritoneum found that regardless of the inflammatory model, the leukocyte counts including neutrophils and the inflammatory response were similar in NE(-/-) and WT mice at all time points. In vitro, neutrophils isolated from the lungs or the peritoneum of NE(-/-) and WT mice had comparable chemotactic and respiratory-burst functions and migrated normally through Matrigel in response to various stimuli. Interestingly, preincubation of human peripheral blood neutrophils with NE physiologic inhibitors did not alter the migration of the cells through Matrigel. In sum, our findings present the first in vivo description that the absence of NE does not impair neutrophil recruitment to inflamed sites and that NE is not required for basement membrane transmigration of neutrophils.

Background. Lung ultrasound has become an emerging tool in acute and critical care medicine. Combined theoretical and hands-on training has been required to teach ultrasound diagnostics. Current computer technology allows for display, explanation, and animation of information in a remote-learning environment. Objective. Development and assessment of an e-learning program for lung ultrasound. Methods. An interactive online tutorial was created. A prospective learning success study was conducted with medical students using a multiple-choice test (Trial A). This e-learning program was used as preparation for a certified course followed by an evaluation of trained doctors (Trial B) by linear analogue scales. Pretests were compared with postcourse tests and sustainability tests as well as a posttest of a one-day custom classroom training. Results. In Trial A, during the learning success study (n = 29), the increase of correct answers was 11.7 to 17/20 in the post-test and to 16.6/20 in the sustainability test (relative change 45.1%, P < 0.0001). E-learning almost equalled scores of classroom-based training regarding gain and retention of factual knowledge. In Trial B, nineteen participating doctors found a 79.5% increase of knowledge (median, 95% CI: 69%; 88%). Conclusion. The basics of lung ultrasound can be taught in a highly effective manner using e-learning.