There was strong agreement among a large cohort of international experts regarding several recommendations for the use of ultrasound in the ICU. Evidence-based recommendations regarding the appropriate use of this technology are a step toward improving patient outcomes in relevant patients.

There was strong agreement among a large cohort of international experts regarding several class 1 recommendations for the use of bedside cardiac ultrasound, echocardiography, in the ICU. Evidence-based recommendations regarding the appropriate use of this technology are a step toward improving patient outcomes in relevant patients and guiding appropriate integration of ultrasound into critical care practice.

Pseudomonas aeruginosa, a ␥-proteobacterium, is motile by means of a single polar flagellum and is chemotactic to a variety of organic compounds and phosphate. P. aeruginosa has multiple homologues of Escherichia coli chemotaxis genes that are organized into five gene clusters. Previously, it was demonstrated that genes in cluster I and cluster V are essential for chemotaxis. A third cluster (cluster II) contains a complete set of che genes, as well as two genes, mcpA and mcpB, encoding methyl-accepting chemotaxis proteins. Mutations were constructed in several of the cluster II che genes and in the mcp genes to examine their possible contributions to P. aeruginosa chemotaxis. A cheB2 mutant was partially impaired in chemotaxis in soft-agar swarm plate assays. Providing cheB2 in trans complemented this defect. Further, overexpression of CheB2 restored chemotaxis to a completely nonchemotactic, cluster I, cheB-deficient strain to near wild-type levels. An mcpA mutant was defective in chemotaxis in media that were low in magnesium. The defect could be relieved by the addition of magnesium to the swarm plate medium. An mcpB mutant was defective in chemotaxis when assayed in dilute rich soft-agar swarm medium or in minimal-medium swarm plates containing any 1 of 60 chemoattractants. The mutant phenotype could be complemented by the addition of mcpB in trans. Overexpression of either McpA or McpB in P. aeruginosa or Escherichia coli resulted in impairment of chemotaxis, and these cells had smooth-swimming phenotypes when observed under the microscope. Expression of P. aeruginosa cheA2, cheB2, or cheW2 in E. coli K-12 completely disrupted wild-type chemotaxis, while expression of cheY2 had no effect. These results indicate that che cluster II genes are expressed in P. aeruginosa and are required for an optimal chemotactic response.Chemotaxis, the directed movement towards chemicals in the environment, is a behavioral response exhibited by most flagellated bacteria. Escherichia coli and Salmonella enterica serovar Typhimurium have served as prototype organisms for studying chemotaxis, and the signal transduction pathway used to effect a chemotactic response in these ␥-proteobacteria is a paradigm for "two-component" and histidine kinase phosphosignaling pathways (5,6,54,55). A set of six chemotaxis proteins acts in concert with receptors called methyl-accepting chemotaxis proteins (MCPs). The current model is that MCPs exist as homodimers that are physically associated with a CheW linker protein dimer and a CheA dimer. There is evidence that these dimeric signaling units exist in cells as supermolecular complexes that are arranged as trimers of dimers (30, 51). On binding an amino acid or other attractant, an MCP dimer undergoes a conformational change that initiates sensory signal transduction by altering the activity of CheA, which is a sensor histidine kinase. CheA-P is a phosophodonor for the response regulator protein, CheY. CheY-P is mobile in the cell and interacts with the rotational "switch" protein FliM in th...

LRP5, along with LRP6 and their Drosophila homolog, Arrow, constitute a novel subclass of the LDL receptor superfamily. The arrangement of structural motifs in these receptors is different from the other members of the superfamily, and only recently have we begun to understand the functional importance of human LRP5 (and LRP6). Whole genome positional cloning studies have identified a number of mutations in LRP5 that underlie inherited human diseases/phenotypes, particularly those involving the skeleton and the eye. A number of studies have illustrated the importance of Lrp5/6/Arrow as a co-receptor with Frizzled for the Wnt proteins and their critical role in the regulation of the Wnt/beta-catenin signaling pathway. The cataloging of these human mutations, in combination with engineered mutations in mice and other studies involving gene/protein modifications, has led to a better understanding of the function of the various domains in LRP5/6. In this review, we discuss a number of studies that have revealed a wide variety of protein-protein interactions that occur with the various structural motifs in the Lrp5 protein. Ultimately, these interactions regulate the activity of the Wnt/beta-catenin signaling pathway and the role it plays in processes such as bone mass accrual and vision.

Inhaled nitric oxide (INO) has been shown to preferentially lower resistance in the pulmonary vasculature. The relative selectiveness of INO in accomplishing this effect makes it an attractive drug to administer as salvage therapy in patients with acute right ventricular failure secondary to pulmonary embolism. We describe 4 cases in which INO was used as a temporizing agent to decrease right ventricular after-load following massive near-fatal pulmonary embolism. All 4 patients survived to hospital discharge. Key words: massive pulmonary embolism; acute cor pulmonale; right heart failure; inhaled nitric oxide. [Respir Care 2012;57(3):444 -448. © 2012 Daedalus Enterprises]

PurposeWe determined whether well-acclimatized humans have a reserve to recruit pulmonary capillaries in response to exercise at high altitude.MethodsAt sea level, lung diffusing capacity for carbon monoxide (DLCO), alveolar-capillary membrane conductance (DmCO), and pulmonary capillary blood volume (Vc) were measured at rest before maximal oxygen consumption () was determined in seven adults. Then, DLCO, DmCO and Vc were measured pre- and post-exhaustive incremental exercise at 5150 m after ~40 days of acclimatization.ResultsImmediately after exercise at high altitude, there was an increase in group mean DmCO (14 ± 10 %, P = 0.040) with no pre- to post-exercise change in group mean DLCO (46.9 ± 5.8 vs. 50.6 ± 9.6 ml/min/mmHg, P = 0.213) or Vc (151 ± 28 vs. 158 ± 37 ml, P = 0.693). There was, however, a ~20 % increase in DLCO from pre- to post-exercise at high altitude (51.2 ± 0.2 vs. 61.1 ± 0.2 ml/min/mmHg) with a concomitant increase in DmCO (123 ± 2 vs. 156 ± 4 ml/min/mmHg) and Vc (157 ± 3 vs. 180 ± 8 ml) in 2 of the 7 participants. There was a significant positive relationship between the decrease in from sea level to high altitude and the change in DLCO and lung diffusing capacity for nitric oxide (DLNO) from rest to end-exercise at high altitude.ConclusionThese data suggest that recruitment of the pulmonary capillaries in response to exercise at high altitude is limited in most well-acclimatized humans but that any such a reserve may be associated with better exercise capacity.

Pilots appear to have a very small increase in prostate cancer incidence, but not in mortality. The clinical significance of this finding is uncertain.

Pilots are at least twice as likely to develop prostate cancer compared to the general population. The implications of these findings are important considering the high prevalence of prostate cancer and the large number of pilots in the workforce.