The mechanics of the lung parenchyma and airway responsiveness to metacholine.

The lung parenchyma is anatomically and mechanically connected to the intraparenchymal airways. Due to forces of interdependence the lung parenchyma represents a mechanical load that opposes bronchial narrowing during airway smooth muscle activation. The mechanical load caused by the parenchyma is a function of the number of the alveolar attachments to the airways, and of the mechanical properties of the parenchyma. The extracellular matrix is a major component of the lung parenchyma responsible of most of its mechanical properties. The excessive airway narrowing observed in the asthmatic population may be the consequence of the altered mechanical properties of the extracellular matrix reducing the mechanical load that opposes airway smooth muscle contraction

Clinical and radiological criteria for the differential diagnosis between asbestosis and idiopathic pulmonary fibrosis: Application in two cases

Introduction: Idiopathic pulmonary fibrosis (IPF) and asbestosis are pulmonary interstitial diseases that may present overlapping clinical aspects in the full-blown phase of the disease. For both clinical entities the gold standard for diagnosis is histological examination, but its execution poses ethical problems, especially when performed for preventive or forensic purposes. Objective: To evaluate the application of internationally accepted clinical, anamnestic and radiological criteria for differential diagnosis between asbestosis and IPF, and to assess the ability to discriminate between the two diseases. Even if clinically similar, the two diseases present extremely different prognostic and therapeutic perspectives. Methods: Two clinical cases of IPF are reported, in which the differential diagnosis was made by studying occupational exposure to asbestos, the onset and progression of clinical symptoms, and the identification of specific radiological elements by means of chest High Resolution Computed Tomography (HRCT). Results: The diagnosis of IPF could be made on the basis of the absence of significant exposure to asbestos, the early onset and rapid progression of dyspnea and restrictive ventilatory defects, in association with a pulmonary radiological pattern characterized by peculiar elements such as honeycombing. Discussion: The diagnostic procedure adopted to make a differential diagnosis with asbestosis provides practical clinical elements facilitating the differentiation between the two forms of pulmonary fibrosis, a fundamental aspect of the activity of the occupational physician

Production of high purity 52g^{52g}Mn from nat^{nat}V targets with α\alpha-beams at cyclotrons

Radioisotope $^{52g}$Mn is of special interest for multimodal imaging. Using state-of-art nuclear reaction codes, we study the alternative nuclear reaction route $^{nat}$V($\alpha$,x)$^{52g}$Mn in comparison with the standard production routes based upon the use of chromium targets. The integral yields of $^{52g}$Mn and contaminants have been evaluated. The main outcome of this investigation is that the production of the main contaminant isotope $^{54}$Mn is expected to be lower than with $^{nat}$Cr. The study also reveals a large spread in the cross-section data set and points out the need of more precise measurements of the reaction $^{nat}$V($\alpha$,x)$^{52g}$Mn as well as the need of a more accurate theoretical description.Comment: Keywords: Cyclotron radionuclide production, $^{52g}$Mn, $^{53}$Mn, $^{54}$Mn, multi-modal imaging,{\alpha}-induced reactions, nuclear reactions modelin

Optical Spectral Signatures of Dusty Starburst Galaxies

We analyse the optical spectral properties of the complete sample of Very Luminous Infrared Galaxies presented by Wu et al. (1998a,b) and we find a high fraction (~50 %) of spectra showing both a strong H_delta line in absorption and relatively modest [OII] emission (e(a) spectra). The e(a) signature has been proposed as an efficient method to identify dusty starburst galaxies and we study the star formation activity and the nature of these galaxies, as well as the effects of dust on their observed properties. We examine their emission line characteristics, in particular their [OII]/H_alpha ratio, and we find this to be greatly affected by reddening. A search for AGN spectral signatures reveals that the e(a)'s are typically HII/LINER galaxies. We compare the star formation rates derived from the FIR luminosities with the estimates based on the H_alpha line and find that the values obtained from the optical emission lines are a factor of 10-70 (H_alpha) and 20-140 ([OII]) lower than the FIR estimates (50-300 M_sun yr^-1). We then study the morphological properties of the e(a) galaxies, looking for a near companion or signs of a merger/interaction. In order to explore the evolution of the e(a) population, we present an overview of the available observations of e(a)'s in different environments both at low and high redshift. Finally, we discuss the role of dust in determining the e(a) spectral properties and we propose a scenario of selective obscuration in which the extinction decreases with the stellar age.Comment: 26 pages, Latex, including 7 postscript figures, accepted for publication in the Astrophysical Journa

Star Formation and Selective Dust Extinction in Luminous Starburst Galaxies

We investigate the star formation and dust extinction properties of very luminous infrared galaxies whose spectra display a strong Hdelta line in absorption and a moderate [OII] emission (e[a] spectrum). This spectral combination has been suggested to be a useful method to identify dusty starburst galaxies at any redshift on the basis of optical data alone. We compare the average e(a) optical spectrum with synthetic spectra that include both the stellar and the nebular contribution, allowing dust extinction to affect differentially the stellar populations of different ages. We find that reproducing the e(a) spectrum requires the youngest stellar generations to be significantly more extinguished by dust than older stellar populations, and implies a strong ongoing star formation activity at a level higher than in quiescent spirals. A model fitting the optical spectrum does not necessarily produce the observed FIR luminosity and this can be explained by the existence of stellar populations which are practically obscured at optical wavelengths. Models in which dust and stars are uniformly mixed yield a reddening of the emerging emission lines which is too low compared to observations: additional foreground reddening is required.Comment: 17 pages, 4 Postscript figures, ApJ in pres

Prospective comparison of long-term pain relief rates after first-time microvascular decompression and stereotactic radiosurgery for trigeminal neuralgia

OBJECTIVE Common surgical treatments for trigeminal neuralgia (TN) include microvascular decompression (MVD), stereotactic radiosurgery (SRS), and radiofrequency ablation (RFA). Although the efficacy of each procedure has been described, few studies have directly compared these treatment modalities on pain control for TN. Using a large prospective longitudinal database, the authors aimed to 1) directly compare long-term pain control rates for first-time surgical treatments for idiopathic TN, and 2) identify predictors of pain control. METHODS The authors reviewed a prospectively collected database for all patients who underwent treatment for TN between 1997 and 2014 at the University of California, San Francisco. Standardized collection of data on preoperative clinical characteristics, surgical procedure, and postoperative outcomes was performed. Data analyses were limited to those patients who received a first-time procedure for treatment of idiopathic TN with > 1 year of follow-up. RESULTS Of 764 surgical procedures performed at the University of California, San Francisco, for TN (364 SRS, 316 MVD, and 84 RFA), 340 patients underwent first-time treatment for idiopathic TN (164 MVD, 168 SRS, and 8 RFA) and had > 1 year of follow-up. The analysis was restricted to patients who underwent MVD or SRS. Patients who received MVD were younger than those who underwent SRS (median age 63 vs 72 years, respectively; p 5 years of follow-up (60 of 164 and 64 of 168 patients, respectively). Immediate or short-term (< 3 months) postoperative pain-free rates (Barrow Neurological Institute Pain Intensity score of I) were 96% for MVD and 75% for SRS. Percentages of patients with Barrow Neurological Institute Pain Intensity score of I at 1, 5, and 10 years after MVD were 83%, 61%, and 44%, and the corresponding percentages after SRS were 71%, 47%, and 27%, respectively. The median time to pain recurrence was 94 months (25th–75th quartiles: 57–131 months) for MVD and 53 months (25th–75th quartiles: 37–69 months) for SRS (p = 0.006). A subset of patients who had MVD also underwent partial sensory rhizotomy, usually in the setting of insignificant vascular compression. Compared with MVD alone, those who underwent MVD plus partial sensory rhizotomy had shorter pain-free intervals (median 45 months vs no median reached; p = 0.022). Multivariable regression demonstrated that shorter preoperative symptom duration (HR 1.005, 95% CI 1.001–1.008; p = 0.006) was associated with favorable outcome for MVD and that post-SRS sensory changes (HR 0.392, 95% CI 0.213–0.723; p = 0.003) were associated with favorable outcome for SRS. CONCLUSIONS In this longitudinal study, patients who received MVD had longer pain-free intervals compared with those who underwent SRS. For patients who received SRS, postoperative sensory change was predictive of favorable outcome. However, surgical decision making depends upon many factors. This information can help physicians counsel patients with idiopathic TN on treatment selection

HCG 16 Revisited: Clues About Galaxy Evolution in Groups

We present new spectroscopic observations of 5 galaxies, members of the unusually active compact group HCG 16, observed using the Palomar 5m telescope. The high signal to noise ratios (S/N $\sim 70$) of the spectra allow us to study the variation of the emission line characteristics and the stellar populations in the nucleus and the circumnuclear regions of the galaxies. The emission line characteristics of these galaxies are complex, varying between Seyfert 2 and LINERs or between LINERs and starbursts. All of the galaxies show traces of intermediate age stellar populations, supporting our previous result that post-starburst galaxies are common in compact groups. The galaxies HCG16--4 and HCG16--5 show double nuclei and therefore could be two cases of recent merger. Our observations support a scenario where HCG 16 was formed by the successive merger of metal poor, low mass galaxies. The galaxies HCG16--1 and HCG16--2, which are more evolved, form the old core of the group. Galaxies HCG16--4 and HCG16--5 are two more recent additions still in a merging phase. Galaxy HCG16--5 is a starburst galaxy which is just beginning to fall into the core. If HCG 16 is representative of compact groups in their early stage, the whole set of observations implies that the formation of compact groups is the result of hierarchical galaxy formation. HCG 16 could be one example of this process operating in the local universe.Comment: tar file containing text and figures is available at http://www.daf.on.br/~reinaldo/paper.htm