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We report the second complete molecular line data release from the {\em Census of High- and Medium-mass Protostars} (CHaMP), a large-scale, unbiased, uniform mapping survey at sub-parsec resolution, of mm-wave line emission from 303 massive, dense molecular clumps in the Milky Way. This release is for all $^{12}$CO $J$=1$\rightarrow$0 emission associated with the dense gas, the first from Phase II of the survey, which includes $^{12}$CO, $^{13}$CO, and C$^{18}$O. The observed clump emission traced by both $^{12}$CO and HCO$^+$ (from Phase I) shows very similar morphology, indicating that, for dense molecular clouds and complexes of all sizes, parsec-scale clumps contain $\Xi$ ~ 75% of the mass, while only 25% of the mass lies in extended (>~ 10 pc) or "low density" components in these same areas. The mass fraction of all gas above a density 10$^9$ m$^{-3}$ is $\xi_9$ >~ 50%. This suggests that parsec-scale clumps may be the basic building blocks of the molecular ISM, rather than the standard GMC concept. Using $^{12}$CO emission, we derive physical properties of these clumps in their entirety, and compare them to properties from HCO$^+$, tracing their denser interiors. We compare the standard X-factor converting $I_{CO}$ to $N_{H_2}$ with alternative conversions, and show that only the latter give whole-clump properties that are physically consistent with those of their interiors. We infer that the clump population is systematically closer to virial equilibrium than when considering only their interiors, with perhaps half being long-lived (10s of Myr), pressure-confined entities which only terminally engage in vigorous massive star formation, supporting other evidence along these lines previously published.
Reinstatement in the light of new evidence? Theophylline has been used as a bronchodilator in the treatment of COPD for over 70 years, but has lost popularity as better tolerated and more effective bronchodilators have been introduced. However, new insights into the molecular action of theophylline have raised the possibility that this old drug may come back into favour as an anti-inflammatory treatment and may even reverse steroid resistance in COPD.1 A paper by Hirano et al in this issue of Thorax provides further support for the anti-inflammatory effects of theophylline in patients with COPD.2 In the major guidelines for the treatment of COPD, theophylline is relegated to a third line bronchodilator after inhaled anticholinergics and β2 agonists. Nevertheless, it is recognised that theophylline is a useful treatment in patients with severe COPD as its withdrawal leads to significant clinical worsening of the disease.3 Many older clinicians have been convinced by its clinical value in severe disease. Traditionally, theophylline was used as a bronchodilator in the treatment of airway disease but, to achieve significant bronchodilatation comparable with that of a β2 agonist, relatively high plasma concentrations are needed (10–20 mg/l). Theophylline relaxes human airway smooth muscle in vitro through inhibition of phosphodiesterases (PDE), enzymes that break down cyclic nucleotides in the …
The term "brittle asthma" was first used in 1977 to describe patients with asthma who maintained a wide variation in peak expiratory flow (PEF) despite high doses of inhaled steroids. 1It was coined at a time when patterns of PEF variability were beginning to be described with respect to clinical patterns of disease, such as the morning dip in PEF 1 2 and the "double dip" pattern of morning and evening dips 3 seen in patients with less well controlled asthma.The brittle asthmatic PEF pattern of variability was identified as a separate group, being described as chaotic showing no such obvious repeating pattern.The significance of the brittle pattern was not completely clear at that time, although the inference was that these patients had more severe asthma that was, by definition, more difficult to control.Three papers published shortly afterwards showed that this chaotic pattern of PEF could lead to death from an acute severe attack 4-6 and the authors raised the possibility that these patients tended to be poorly compliant with treatment.Nevertheless, not all non-compliant patients showed this chaotic pattern, so clearly other factors were important.However, it is not clear how these patients would fit into a classification of severe asthma which would include all those patients at risk of death or repeated hospital admissions.Some physicians are unhappy with brittle asthma being classified as a separate asthma phenotype, regarding these patients as simply the severe end of the spectrum.However, it is our belief that definition of diVering asthma phenotypes is important, so what follows represents our view that brittle asthma should be considered as a specific asthma phenotype.We suggest how further study of patients of this type may help in unravelling the pathogenesis and treatment of at risk asthma.
The placement of stents in coronary arteries after coronary angioplasty has been investigated as a way of treating abrupt coronary-artery occlusion related to the angioplasty and of reducing the late intimal hyperplasia responsible for gradual re-Stenosis of the dilated lesion.
Contemporary metallic drug-eluting stents are associated with very good 1-year outcomes but an ongoing risk of stent-related adverse events (thrombosis, myocardial infarction, restenosis) after 1 year. The pathogenesis of these very late events is likely related to the permanent presence of the metal stent frame or polymer. Bioresorbable scaffolds have been developed to provide drug delivery and mechanical support functions similar to metallic drug-eluting stents, followed by complete resorption with recovery of more normal vascular structure and function, potentially improving very late clinical outcomes. A first-generation bioresorbable scaffold has been demonstrated to be noninferior to a contemporary metallic drug-eluting stents for overall 1-year patient-oriented and device-oriented outcomes. Increased rates of scaffold thrombosis and target vessel-related myocardial infarction were noted that may be mitigated by improved patient and lesion selection, procedural technique, and device iteration. Large-scale, randomized, clinical trials are ongoing to determine the long-term relative efficacy and safety of bioresorbable scaffolds compared with current metallic drug-eluting stents.
We investigated the distribution of adrenergic receptors in ferret trachea using autoradiography. [3H]Dihydroalprenolol, used to identify beta–-adrenoceptors, revealed a high density of specific binding sites over surface epithelium and submucosal glands, with less labelling of smooth muscle. [3H] prazosin labelling showed that alpha 1-receptors were numerous in glands and epithelium, but sparse in smooth muscle. Comparison of adrenergic receptor densities in tracheal sections from the same animals showed a rank order for submucosal glands of alpha l > beta, for epithelium beta > alphai and for smooth muscle beta > alpha1. Within the submucosal glands, alpha1 and beta-adrenergic receptors were differentially distributed, with alpha1 receptors being significantly more numerous over serous than mucous cells and beta receptors being significantly more numerous over mucous than serous cells. This technique provides insight into adrenergic regulation of airway function and should be useful in investigations of how relative receptor densities may be altered in disease.
