Research in pulmonary drug delivery has focused mainly on new particle or device technologies to improve the aerosol generation and pulmonary deposition of inhaled drugs. Although substantial progress has been made in this respect, no significant advances have been made that would lead pulmonary drug delivery beyond the treatment of some respiratory diseases. One main reason for this stagnation is the still very scarce knowledge about the fate of inhaled drug or carrier particles after deposition in the lungs. Improvement of the aerosol component alone is no longer sufficient for therapeutic success of inhalation drugs; a paradigm shift is needed, with an increased focus on the pulmonary barriers to drug delivery. In this Review, we discuss some pathophysiological disorders that could benefit from better control of the processes after aerosol deposition, and pharmaceutical approaches to achieve improved absorption across the alveolar epithelium, prolonged pulmonary clearance, and targeted delivery to specific cells or tissues.
Source: Lancet
Lung
Dietary selenium fails to influence cigarette smoke-induced lung tumorigenesis in A/J mice.
Higher dietary sodium selenite did not inhibit the induction of lung tumors. • Higher dietary selenium increased selenium and GPx protein levels in the lung. • Dietary selenium did not affect lung SOD levels.
Abstract
The goal of the study was to determine if dietary selenium inhibited the induction of lung tumorigenesis by cigarette smoke in A/J mice. Purified diets containing 0.15, 0.5, or 2.0mg/kg selenium in the form of sodium selenite were fed to female A/J mice. Half of the mice in each dietary group were exposed to cigarette smoke 6h/day, 5days/week for five months followed by a four month recovery period in ambient air, while the other half were used as controls. After the recovery period, the mice were euthanized, and their lungs were removed for further analysis. Mice exposed to smoke had a higher tumor incidence and a higher tumor multiplicity, whereas dietary Se did not affect either the tumor incidence or tumor multiplicity. An increase in dietary selenium led to increased levels of selenium in the lung as well as GPx protein levels, but dietary Se did not affect lung SOD protein levels. In conclusion, these data confirm the carcinogenic activity of cigarette smoke in mice but show that dietary Se provided as sodium selenite does not affect smoke-induced carcinogenesis in this model.
Source: cancer letters
Evaluating Solitary Pulmonary Nodules.
Particularly for small peripheral nodules, skip the conventional bronchoscopy, and consider navigational bronchoscopy.
With increasing use of chest computed tomography (CT) scans, particularly in the setting of lung cancer screening, a marked rise has occurred in incident discoveries of solitary pulmonary nodules (SPNs). Limited data are available to guide further evaluation of SPNs, but two recent studies help clarify this process.
Researchers studied routine use of conventional bronchoscopy for evaluating SPNs as part of a Dutch-Belgian CT lung cancer screening trial. The criteria for a positive CT results were nodule diameter >10 mm or fast volume doubling time as determined by serial CT. Of 318 SPNs meeting these criteria (average maximum diameter, 14.6 mm), 178 eventually were found to be malignant, but conventional bronchoscopic biopsy results were positive in only 24 cases (sensitivity, 13%). The diagnostic yield was better for larger nodules and endobronchial lesions. In 11 nodules visible in airways, the sensitivity of bronchoscopy was 82%.
A variety of “navigational bronchoscopy” tools are available to better localize small SPNs. These advanced techniques include global positioning system–like guidance to the SPN and ultra-thin bronchoscopes that allow access to smaller airways and focal sampling. A meta-analysis of 39 small studies revealed a 70% diagnostic yield (range, 46%–86%) with navigational bronchoscopy techniques (all types combined). Adverse event rates were very low.
Comment: Conventional bronchoscopy should not be used routinely to evaluate small or peripheral solitary pulmonary nodules. In trained hands, navigational bronchoscopy has much greater diagnostic yield for SPN evaluation. Both types of bronchoscopy can be used in conjunction with endobronchial ultrasound if lymph node biopsy also is needed. Decisions about transthoracic needle aspiration versus navigational bronchoscopy should be made based on nodule characteristics (i.e., size, location), patient’s risk for adverse events, and site expertise in these procedures.
Source: Journal Watch General Medicine
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