Increased body mass index does not impact the imaging quality of focused assessment with sonography in trauma.

BACKGROUND: Many clinicians believe that a patient's body mass index (BMI) affects the likelihood of obtaining high quality ultrasound images. OBJECTIVES: To assess the hypothesis that increased BMI is associated with worsening focused assessment with sonography in trauma (FAST) image quality. METHODS: We conducted a retrospective single-center study of FAST examinations performed in a large academic emergency department (ED) with fellowship-trained emergency ultrasonography faculty performing quality assurance review. RESULTS: Mean (SD) BMI was 28.0 (6.6) among the 302 included studies. The overall quality rating tended to decrease as BMI increased but did not achieve statistical significance in a univariable setting (P = .06) or after adjustment for age and sex (P = .06). Operators perception of image adequacy was largely unaffected by BMI, with the exception of the pericardial view. CONCLUSION: This study did not identify a statistically significant difference in FAST quality with increased BMI. This result may help assuage clinician concerns about ultrasonography for patients in the ED.

FGF and Notch signaling in sensory neuron formation: a multifactorial approach to understanding signaling pathway hierarchy.

The ophthalmic trigeminal (opV) placode exclusively gives rise to sensory neurons, making it a good model to study the molecular regulation of sensory neurogenesis. A number of signaling pathways including Wnt, PDGF, FGF, and Notch have been shown to be involved in the process of opV placode cell development. However, the regulatory relationships between these signaling pathways in placode cells are still unknown and have been difficult to study experimentally. Using a novel multifactorial approach in chick embryos that allows for inhibition of FGF throughout the tissue or in individual cells, with simultaneous inactivation of Notch signaling, we investigated the potential interaction between the FGF and Notch signaling pathways in trigeminal sensory neurogenesis. This study builds on prior research describing the individual role of FGF signaling or Notch signaling in opV placode development, where blocking FGF signaling resulted in neurogenesis failure, while blocking Notch signaling resulted in enhanced neurogenesis. Reported here, blocking both pathways simultaneously resulted in a reduction in the number of cells delaminating from the opV placode and undergoing sensory neuron differentiation. Further, Notch inhibition alone did not lead to an increase in the number of cells expressing FGFR4 or in the FGFR4 expression domain, but did result in a highly fragmented basal lamina, which was reversed when blocking FGF signaling. Cumulatively, the results presented here do not support a model of Notch/FGF interdependence, rather that FGF and Notch act in parallel to promote sensory neurogenesis.

Collision cross sectional areas from analysis of Fourier transform ion cyclotron resonance line width: a new method for characterizing molecular structure.

We demonstrate a technique for determining molecular collision cross sections via measuring the variation of Fourier transform ion cyclotron resonance (FTICR) line width with background damping gas pressure, under conditions where the length of the FTICR transient is pressure limited. Key features of our method include monoisotopic isolation of ions, the pulsed introduction of damping gas to a constant pressure using a pulsed leak valve, short excitation events to minimize collisions during the excitation, and proper choice of damping gas (Xe is superior to He). The measurements are reproducible within a few percent, which is sufficient for distinguishing between many structural possibilities and is comparable to the uncertainty in cross sections calculated from computed molecular structures. These techniques complement drift ion mobility measurements obtained on dedicated instruments. They do not require a specialized instrument, but should be easily performed on any FTICR mass spectrometer equipped with a pulsed leak valve.