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Cross-Linked Polymers for Drug Delivery Systems
Published in Munmaya K. Mishra, Applications of Encapsulation and Controlled Release, 2019
The nasal cavity is made up of three regions: respiratory, olfactory, and vestibule 50–53. The anterior region of the nasal cavity, which is surrounded by cartilage with small hairs, is known as the nasal vestibule. The nasal turbinates are responsible for the turbulent airflow through the nasal passages, thereby resulting in a good contact between the inhaled air and the mucosal surface found in the respiratory region. The respiratory region contains four important cell types, which are involved in the active transport processes, in mucociliary clearance, and in trapping moisture, thereby keeping the mucosa moist; these are the basal, goblet, non-ciliated, and ciliated columnar cells present in the respiratory epithelium. The ciliated and non-ciliated cells enhance the surface area, and this is a region where drug absorption occurs50–53.
An Unsupervised Parametric MixtureModel for Automatic Three-DimensionalLung Segmentation
Published in Ayman El-Baz, Jasjit S. Suri, Lung Imaging and CADx, 2019
Mohammed Ghazal, Samr Ali, Mohanad AlKhodari, Ayman El-Baz
A nonrespiratory function of lungs is done through the respiratory epithelium, which is a barrier that filters the inspired air from fibrin clumps and chemicals before it reaches the respiratory system, mainly alveoli. In the physical filtration process, lungs act as filters for blood-borne substances. The pulmonary capillaries are around 7 µm in diameter. This size is considered small for the pulmonary circulation to act as filters. However, after coughing, the pressure increases in the right atrium, which produces demonstrable blood flow between both the left and the right atria. Thus, gas emboli pass through the pulmonary capillary or bypass the lung entirely through the foramen ovale [10]. Without providing such filtering processes within lungs, the risk of increased emboli in the arterial system increases. In addition, emboli may pass the alveoli through precapillary anastomoses that exist in the pulmonary circulation. However, microcirculation maintains alveolar perfusion in front of a large degree of embolization by its ability to dilate pulmonary capillaries. This helps minimize dangerous hypertension following pulmonary embolus, and therefore the lungs succeed in maintaining their physical filtering functionality [11]. The lungs are considered the main defensive organs that provide protection from any substances that might be absorbed through the breathing process. Moreover, they provide a metabolic function, as they include a fiberinolytic system that undergoes clots in the pulmonary vessels [4, 10].
The potential hazardous effect of exposure to iron dust in Egyptian smoking and nonsmoking welders
Published in Archives of Environmental & Occupational Health, 2018
Naglaa Abd El Khalik Gobba, Abdelmaksoud Hussein Ali, Dalia E. El Sharawy, Mohammed Abdalla Hussein
Iron deposition in the lung is associated with tissue injury and fibrosis. Accumulation of iron in the lung has been demonstrated in smokers and patients with various pulmonary diseases.1 In smokers, the increased iron deposition in bronchoalveolar lavage (BAL) fluid and/or alveolar macrophages2,3 is related to areas of emphysema or lung toxicity.4 The National Institute of Occupational Safety and Health (NIOSH) reported that there is an elevated risk of lung cancer among welders who are smokers or are exposed to welding fumes.5 Several studies have also supported the view that welding fumes could increase the risk of lung cancer.6–13 For example, Meo et al.14 conducted a study on Pakistani welders and observed that mean parameters of pulmonary functions such as forced expiratory volume in first second (FEV1), FEV1/forced vital capacity (FVC), and peak expiratory flow rate (PEFR) were below the average with exposures longer than 9 years. In addition, welding exposure is associated with increased risk for occupational asthma.15 Although numerous studies suggest there is an association between exposure to iron fumes or dust at work and lung cancer risk,7,8,16 some studies reported that welding fumes and iron are generally neglected because the focus falls upon nickel, chromium or chromium VI, and other possible carcinogens.17,18 In addition, there has been a debate about whether exposure to mild steel or stainless steel could lead to an increased risk of lung cancer among welders.19 Smoking is a well-known independent risk factor for lung inflammation,20–22 probably due to its adverse effects on respiratory epithelium.23 Simeonova and Luster24 showed that surface iron was crucial for the induction of tumor necrosis factor-α (TNF-α) in alveolar macrophages. Ghio and coworkers25 found that surface-complexed iron on silicate particles increased inflammation, oxidant production, and leukotriene B4 (LTB4) release by macrophages. The aim of the present study was to identify the exposure–response relationship of occupational exposure to iron fumes or dust and welding fumes and the risk of lung inflammation in Egyptian smoking and nonsmoking welders.