Background: Low-dose computed tomography (LDCT) scan for lung cancer screening is underutilized.Studies suggest that up to one-third of providers do not know the current lung cancer screening guidelines.Thus, identifying the barriers to utilization of LDCT scan is essential. Methods: Primary care providers in three different healthcare settings in the United States were surveyed to assess provider knowledge of LDCT scan screening criteria, lung cancer screening practices, and barriers to the utilization of LDCT scan screening. Fisher's Exact, Chi-Squared, and Kruskal-Wallis tests were used to compare provider responses. Multivariable logistic regression was used to test the association between provider characteristics and the likelihood of utilizing LDCT scan for lung cancer screening. Results: The survey was sent to 614 providers, with a 15.7% response rate. Overall, 29.2% of providers report never ordering LDCT scans for eligible patients. Providers practicing at a community or academic hospital more frequently order LDCT scans than those practicing at a safety net hospital. Academic-and community-based providers received a significantly higher mean knowledge score than safety net-based providers [academic 6.84 (SD 1.33), community 6.72 (SD 1.46), safety net 5.85 (SD 1.38); P<0.01]. Overall, only 6.2% of respondents correctly identified all six Centers for Medicare and Medicaid Services eligibility criteria when challenged with three incorrect criteria. Common barriers to utilization of LDCT scan included failure of the electronic medical record (EMR) to notify providers of eligible patients (54.7%), patient refusal (37%), perceived high false-positive rate leading to unnecessary procedures (18.9%), provider time constraints (16.8%), and lack of insurance coverage (13.7%). Conclusions: Provider knowledge of lung cancer screening guidelines varies, perhaps contributing to underutilization of LDCT scan for lung cancer screening. Improved provider education at safety net hospitals and improving EMR-based best practice alerts may improve the rate of lung cancer screening.

Rigid bronchoscopy with silicone airway stenting is a safe and effective option for the management of benign central airway obstruction. Our results highlight several strategies to improve stent duration.

Endothelial progenitor cells (EPCs) are bone marrow-derived cells that have the propensity to differentiate into mature endothelial cells (ECs). The transplantation of EPCs has been shown to enhance in vivo postnatal neo-vasculogenesis, as well as repair infarcted myocardium. Via the whole-cell patch clamp technique, numerous types of ion channels have been detected in EPCs, including the inward rectifier potassium channel (IKir), Ca2+-activated potassium channel (IKCa), and volume-sensitive chloride channel, but their influence on the differentiation of EPCs has yet to be characterized. The present study was designed to investigate: (1) which ion channels have the most significant impact on the differentiation of EPCs; (2) what role ion channels play in the functional development of EPCs; (3) the mRNA and protein expression levels of related ion channel subunits in EPCs. In our study, EPCs were obtained from the peripheral blood of healthy adults and cultured with endothelial growth factors. When EPCs differentiate into mature ECs, they lose expression of the stem cell/progenitor marker CD133, as analyzed by flow cytometry (0.44±0.20 %). However, treatment with the potassium channel inhibitor, tetraethylammonium (TEA) results in an increase in CD133+ cells (25.50±7.55 %). In a functional experiment, we observed a reduction in the capacity of TEA treated ECs (differentiated from EPCs) to form capillary tubes when seeded in Matrigel. At the mRNA and protein levels, we revealed several K+ subtypes, including KCNN4 for IKCa, KCNNMA1 for BKCa and Kir3.4 for IKir. These results demonstrate for the first time that potassium channels play a significant role in the differentiation of EPCs. Moreover, inhibition of potassium channels may depress the differentiation of EPCs and the significant potassium channel subunits in EPCs appear to be IKCa, BKCa and Kir3.4.

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BackgroundTreatment of LQT2 is inadequate. Many drugs which can pharmacologically rescue defective protein trafficking in LQT2 also result in potent blockade of HERG current, negating their therapeutic benefit. It is reported that PD-118057 and thapsigargin can rescue LQT2 without hERG channel blockade, but the precise mechanism of action is unknown. Furthermore, the effect of PD-118057 and thapsigargin on the dominant negative E637K-hERG mutant has not been previously investigated.ObjectiveIn this study, we investigated: (a) the effect of PD-118057 and thapsigargin on the current amplitudes of WT-hERG and WT/E637K-hERG channels; (b) the effect of PD-118057 and thapsigargin on the biophysical properties of WT-hERG and WT/E637K-hERG channels; (c) whether drug treatment can rescue channel processing and trafficking defects of the WT/E637K-hERG mutant.MethodsThe whole-cell Patch-clamp technique was used to assess the effect of PD-118057 and thapsigargin on the electrophysiological characteristics of the rapidly activating delayed rectifier K+ current (Ikr) of the hERG protein channel. Western blot was done to investigate pharmacological rescue on hERG protein channel function.ResultsIn our study, PD-118057 was shown to significantly enhance both the maximum current amplitude and tail current amplitude, but did not alter the gating and kinetic properties of the WT-hERG channel, with the exception of accelerating steady-state inactivation. Additionally, thapsigargin shows a similar result as PD-118057 for the WT-hERG channel, but with the exception of attenuating steady-state inactivation. However, for the WT/E637K-hERG channel, PD-118057 had no effect on either the current or on the gating and kinetic properties. Furthermore, thapsigargin treatment did not alter the current or the gating and kinetic properties of the WT/E637K-hERG channel, with the exception of opening at more positive voltages.ConclusionOur findings illustrate that neither PD-118057 nor thapsigargin play a role in correcting the dominant-negative effect of the E637K-hERG mutant.