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Deposition of Aerosol Particles in Human Respiratory System
Published in Katarzyna Majchrzycka, Nanoaerosols, Air Filtering and Respiratory Protection, 2020
The first element of the LA is a trachea, a cylindrical tube of about 2 cm diameter and about 10 cm length, separating the two bronchi: left and right, transporting the air to the left and right lung. Bronchi are then branching out many times, creating a system of bronchioles that ended with alveoli (Figure 2.4). The walls of the trachea and of the few next bronchi branches are reinforced by cartilage rings. Stripes of smooth muscles are located on these parts of airways walls, as well as multiple protuberances called cilia and multiple mucous glands, which secretion pads out the duct walls, which facilitates capturing contaminants. The cilia movement causes the transport of mucus along with the deposited exogenous particles in the direction of the larynx. The walls of bronchioles are not equipped with cartilages, which makes them susceptible to collapse under pressure. Bronchioles transition into alveolar ducts, which then transition into alveoli.
Bronchial Asthma and Idiopathic Pulmonary Fibrosis as Potential Targets for Hematopoietic Stem Cell Transplantation
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Júlio C. Voltarelli, Eduardo A. Donadi, José A. B. Martinez, Elcio O. Vianna, Willy Sarti
Bronchial hyperresponsiveness is defined as an increased ability of the airway to narrow its caliber after exposure to nonspecific stimuli, including bronchoconstrictor pharmacologic agonists, such as histamine, acethylcholine, methacoline, and many other stimuli. After nonspecific stimuli provocation, patients presenting with bronchial hyperresponsiveness exhibit a 20% fall in the forced expiratory volume in the first second (FEV1). Usually, the magnitude of airway hyperresponsiveness correlates with the severity of asthma and with variations of the peak expiratory flow rate. An improvement in FEV1 may be observed after the inhalation of bronchodilators. The development of bronchial hyperresponsiveness in asthmatics has been associated with persistent airway inflammation, mainly caused by the activation of inflammatory cells such as mast cells, eosinophils, neutrophils and lymphocytes. Although the mechanisms responsible for airway hyperresponsiveness are not completely understood, the consequences of the persistent inflammation include airway wall thickening, loss of airway epithelium, airway edema, and altered airway smooth muscle function.21
Nanomedicines for the Treatment of Respiratory Diseases
Published in Sarwar Beg, Mahfoozur Rahman, Md. Abul Barkat, Farhan J. Ahmad, Nanomedicine for the Treatment of Disease, 2019
Brahmeshwar Mishra, Sundeep Chaurasia
Among obstructive pulmonary diseases, bronchial asthma and COPD are among global health hazards in terms of mortality and morbidity. The basis of nanomedicine activities in diseases were discussed in a study by John et al. in Ann Arbor, MI (John et al., 2003). For bronchial asthma, experimental studies have already been conducted to assess the use of such nanosystems. Nanomedicine technology was applied to discover a potent nanoparticle P-selectin antagonist with strong anti-inflammatory effects in a murine model allergic asthma (John et al., 2003). The background of the study was to assess the role of P-selectin for the development and progression of peri-bronchial inflammation in allergic airway disease. Since selective P-selectin inhibitors may lead to an attenuation of the ongoing inflammatory processes present in allergic bronchial asthma, a panel of novel P-selectin inhibitors were synthesized using polyvalent polymeric nanoparticles (John et al., 2003). First, a construct that binds efficiently to P-selectin was generated by assembling a particle with the ligands acting as mimetics of the binding elements that mediate the adhesion of P-selectin to its ligand P-selectin glycoprotein ligand–1 (PSGL–1). Then, an in vitro assay was used to evaluate the different inhibitors by examining the interactions between P-selectin coated capillary tubes and circulating cells. It was shown that they preferentially bind to selectins expressed on activated endothelial cells (John et al., 2003). After these in vitro experiments, in vivo studies were conducted using a murine model of allergic asthma and a significant reduction of allergen-induced peri-bronchial inflammation airway and airway hyperreactivity present (John et al., 2003). This indicating the validity of the new compounds.
Acute effects of ambient air pollution exposure on lung function in the elderly in Hangzhou, China
Published in International Journal of Environmental Health Research, 2023
Hui Liao, Shuchang Chen, Shanshan Xu, Ye Lv, Weiyan Liu, Hong Xu
Healthy elderly people of both sexes aged between 60 and 75 years were included in this study. To ensure the reliability of the results, the study population had some limitations. The inclusion criteria were as follows: (a) participants aged between 60 and 75 years, (b) duration of residence in the local community for more than five years, and (c) voluntary participation. The exclusion criteria were as follows: (a) severe mental disease and inability to cooperate with the lung function test, (b) underlying lung disease, such as severe bronchial asthma, bronchiectasis, tuberculosis, and COPD; c) acute lung infectious diseases or acute exacerbations of COPD and a history of antibiotics during the study period; and (d) there were fewer than 1/3 questions answered, and all answered the same.
Assessing the in vitro toxicity of airborne (nano)particles to the human respiratory system: from basic to advanced models
Published in Journal of Toxicology and Environmental Health, Part B, 2023
Maria João Bessa, Fátima Brandão, Fernanda Rosário, Luciana Moreira, Ana Teresa Reis, Vanessa Valdiglesias, Blanca Laffon, Sónia Fraga, João Paulo Teixeira
The respiratory system is primarily composed of the nose, airways, and parenchyma. The upper respiratory tract allows the passage of air and protects the lower respiratory regions from external injuries (Thomas 2013), while gas exchange occurs in the lower respiratory tract such as the alveoli (Weibel, Sapoval, and Filoche 2005). Along the respiratory tract, cell types and morphology vary (Figure 1), which also may be affected in pulmonary diseases (Whitsett and Alenghat 2015). As illustrated in Figure 1, the upper airways are lined with a pseudostratified epithelium that is composed of ciliated, secretory (goblet and club cells), neuro-endocrine, and basal cells, these latter acting as progenitor cells for various cell types of the airway epithelium (Crapo et al. 1982; Hiemstra, McCray, and Bals 2015). The bronchioles are lined by ciliated cuboidal epithelium, with a small number of non-ciliated club cells that are more dominant in the distal portion (Khan and Lynch 2018). In addition, the alveolar epithelium is important for maintaining lung homeostasis and is constituted by cuboidal alveolar epithelial type 1 cells (AEC1) and type 2 cells (AEC2).
Modeling pressure relationships of inspired air into the human lung bifurcations through simulations
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2018
Parya Aghasafari, Israr B.M. Ibrahim, Ramana Pidaparti
Geometric model is based on Jinxiang et al. model [28]. They obtained an MRI from a healthy human lung and used Mimics software to define a 3D structure for lung based on MRI results and generated mesh by using Gambit Fig(1). The airways include a series of branching tubes and integrate from trachea that has essential role in providing air flow to and from the lungs for respiration. Trachea would be divided into right and left main bronchi, which divide into lobar and segmental bronchi. This will continue to the terminal bronchioles that are the smallest airways without alveoli. All of these bronchi make up the conducting airways. These regions lead inspired air to the gas-exchanging region of the lung which is built by, terminal and respiratory bronchioles, alveolar ducts and alveolar sacs [29].