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Cell and Tissue Research Mar 2017To fulfill the task of gas exchange, the lung possesses a huge inner surface and a tree-like system of conducting airways ventilating the gas exchange area. During lung... (Review)
Review
To fulfill the task of gas exchange, the lung possesses a huge inner surface and a tree-like system of conducting airways ventilating the gas exchange area. During lung development, the conducting airways are formed first, followed by the formation and enlargement of the gas exchange area. The latter (alveolarization) continues until young adulthood. During organogenesis, the left and right lungs have their own anlage, an outpouching of the foregut. Each lung bud starts a repetitive process of outgrowth and branching (branching morphogenesis) that forms all of the future airways mainly during the pseudoglandular stage. During the canalicular stage, the differentiation of the epithelia becomes visible and the bronchioalveolar duct junction is formed. The location of this junction stays constant throughout life. Towards the end of the canalicular stage, the first gas exchange may take place and survival of prematurely born babies becomes possible. Ninety percent of the gas exchange surface area will be formed by alveolarization, a process where existing airspaces are subdivided by the formation of new walls (septa). This process requires a double-layered capillary network at the basis of the newly forming septum. However, in parallel to alveolarization, the double-layered capillary network of the immature septa fuses to a single-layered network resulting in an optimized setup for gas exchange. Alveolarization still continues, because, at sites where new septa are lifting off preexisting mature septa, the required second capillary layer will be formed instantly by angiogenesis. The latter confirms a lifelong ability of alveolarization, which is important for any kind of lung regeneration.
Topics: Animals; Embryonic Development; Humans; Lung; Organogenesis; Pulmonary Alveoli
PubMed: 28144783
DOI: 10.1007/s00441-016-2545-0 -
Advances in Physiology Education Sep 2017Because the heart and lungs are confined within the thoracic cavity, understanding their interactions is integral for studying each system. Such interactions include... (Review)
Review
Because the heart and lungs are confined within the thoracic cavity, understanding their interactions is integral for studying each system. Such interactions include changes in external constraint to the heart, blood volume redistribution (venous return), direct ventricular interaction (DVI), and left ventricular (LV) afterload. During mechanical ventilation, these interactions can be amplified and result in reduced cardiac output. For example, increased intrathoracic pressure associated with mechanical ventilation can increase external constraint and limit ventricular diastolic filling and, therefore, output. Similarly, high intrathoracic pressures can alter blood volume distribution and limit diastolic filling of both ventricles while concomitantly increasing pulmonary vascular resistance, leading to increased DVI, which may further limit LV filling. While LV afterload is generally considered to decrease with increased intrathoracic pressure, the question arises if the reduced LV afterload is primarily a consequence of a reduced LV preload. A thorough understanding of the interaction between the heart and lungs can be complicated but is essential for clinicians and health science students alike. In this teaching review, we have attempted to highlight the present understanding of certain salient aspects of cardiopulmonary physiology and pathophysiology, as well as provide a resource for multidisciplined health science educators and students.
Topics: Heart; Humans; Lung; Physiology
PubMed: 28679570
DOI: 10.1152/advan.00190.2016 -
BMC Pulmonary Medicine Oct 2018Pulmonary function tests (PFTs) are routinely performed in the upright position due to measurement devices and patient comfort. This systematic review investigated the...
BACKGROUND
Pulmonary function tests (PFTs) are routinely performed in the upright position due to measurement devices and patient comfort. This systematic review investigated the influence of body position on lung function in healthy persons and specific patient groups.
METHODS
A search to identify English-language papers published from 1/1998-12/2017 was conducted using MEDLINE and Google Scholar with key words: body position, lung function, lung mechanics, lung volume, position change, positioning, posture, pulmonary function testing, sitting, standing, supine, ventilation, and ventilatory change. Studies that were quasi-experimental, pre-post intervention; compared ≥2 positions, including sitting or standing; and assessed lung function in non-mechanically ventilated subjects aged ≥18 years were included. Primary outcome measures were forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC, FEV1/FVC), vital capacity (VC), functional residual capacity (FRC), maximal expiratory pressure (PEmax), maximal inspiratory pressure (PImax), peak expiratory flow (PEF), total lung capacity (TLC), residual volume (RV), and diffusing capacity of the lungs for carbon monoxide (DLCO). Standing, sitting, supine, and right- and left-side lying positions were studied.
RESULTS
Forty-three studies met inclusion criteria. The study populations included healthy subjects (29 studies), lung disease (nine), heart disease (four), spinal cord injury (SCI, seven), neuromuscular diseases (three), and obesity (four). In most studies involving healthy subjects or patients with lung, heart, neuromuscular disease, or obesity, FEV1, FVC, FRC, PEmax, PImax, and/or PEF values were higher in more erect positions. For subjects with tetraplegic SCI, FVC and FEV1 were higher in supine vs. sitting. In healthy subjects, DLCO was higher in the supine vs. sitting, and in sitting vs. side-lying positions. In patients with chronic heart failure, the effect of position on DLCO varied.
CONCLUSIONS
Body position influences the results of PFTs, but the optimal position and magnitude of the benefit varies between study populations. PFTs are routinely performed in the sitting position. We recommend the supine position should be considered in addition to sitting for PFTs in patients with SCI and neuromuscular disease. When treating patients with heart, lung, SCI, neuromuscular disease, or obesity, one should take into consideration that pulmonary physiology and function are influenced by body position.
Topics: Humans; Lung; Posture; Respiratory Function Tests
PubMed: 30305051
DOI: 10.1186/s12890-018-0723-4 -
Journal of Digital Imaging Aug 2014This study presents a completely automated method for separating the left and right lungs using free-formed surface fitting on volumetric computed tomography (CT). The...
This study presents a completely automated method for separating the left and right lungs using free-formed surface fitting on volumetric computed tomography (CT). The left and right lungs are roughly divided using iterative 3-dimensional morphological operator and a Hessian matrix analysis. A point set traversing between the initial left and right lungs is then detected with a Euclidean distance transform to determine the optimal separating surface, which is then modeled from the point set using a free-formed surface-fitting algorithm. Subsequently, the left and right lung volumes are smoothly and directly separated using the separating surface. The performance of the proposed method was estimated by comparison with that of a human expert on 44 CT examinations. For all data sets, averages of the root mean square surface distance, maximum surface distance, and volumetric overlap error between the results of the automatic and the manual methods were 0.032 mm, 2.418 mm, and 0.017 %, respectively. Our study showed the feasibility of automatically separating the left and right lungs by identifying the 3D continuous separating surface on volumetric chest CT images.
Topics: Algorithms; Cone-Beam Computed Tomography; Feasibility Studies; Humans; Imaging, Three-Dimensional; Lung; Organ Size; Pattern Recognition, Automated; Pulmonary Disease, Chronic Obstructive; Radiographic Image Interpretation, Computer-Assisted; Reproducibility of Results; Retrospective Studies
PubMed: 24691827
DOI: 10.1007/s10278-014-9680-5 -
International Journal of Molecular... Aug 2020The evolutionarily-conserved Notch signaling pathway plays critical roles in cell communication, function and homeostasis equilibrium. The pathway serves as a... (Review)
Review
The evolutionarily-conserved Notch signaling pathway plays critical roles in cell communication, function and homeostasis equilibrium. The pathway serves as a cell-to-cell juxtaposed molecular transducer and is crucial in a number of cell processes including cell fate specification, asymmetric cell division and lateral inhibition. Notch also plays critical roles in organismal development, homeostasis, and regeneration, including somitogenesis, left-right asymmetry, neurogenesis, tissue repair, self-renewal and stemness, and its dysregulation has causative roles in a number of congenital and acquired pathologies, including cancer. In the lung, Notch activity is necessary for cell fate specification and expansion, and its aberrant activity is markedly linked to various defects in club cell formation, alveologenesis, and non-small cell lung cancer (NSCLC) development. In this review, we focus on the role this intercellular signaling device plays during lung development and on its functional relevance in proximo-distal cell fate specification, branching morphogenesis, and alveolar cell determination and maturation, then revise its involvement in NSCLC formation, progression and treatment refractoriness, particularly in the context of various mutational statuses associated with NSCLC, and, lastly, conclude by providing a succinct outlook of the therapeutic perspectives of Notch targeting in NSCLC therapy, including an overview on prospective synthetic lethality approaches.
Topics: Animals; Carcinoma, Non-Small-Cell Lung; Humans; Lung; Lung Neoplasms; Models, Biological; Receptors, Notch; Signal Transduction
PubMed: 32784481
DOI: 10.3390/ijms21165691 -
Korean Journal of Radiology Oct 2021To describe the anatomic locations and imaging features of posterior lung herniation in unilateral pulmonary agenesis and aplasia, focusing on radiograph-CT/MRI...
OBJECTIVE
To describe the anatomic locations and imaging features of posterior lung herniation in unilateral pulmonary agenesis and aplasia, focusing on radiograph-CT/MRI correlation.
MATERIALS AND METHODS
A total of 10 patients (seven with pulmonary agenesis and three with pulmonary aplasia, male: female = 1:9, mean age 7.3 years, age range from 1 month to 20 years) were included. Chest radiographs (n = 9), CT (n = 9), and MRI (n = 1) were reviewed to assess the type of lung underdevelopment, presence of anterior and posterior lung herniation, bronchus origin, supplying artery, and draining vein of the herniated lung.
RESULTS
Pulmonary agenesis/aplasia more commonly affected the left lung (n = 7) than the right lung (n = 3). Anterior lung herniation was observed in nine of the 10 patients. Posterior lung herniation was observed in seven patients with left pulmonary agenesis/aplasia. Two patients showed posterior lung herniation crossing the midline but not beyond the aorta, and five patients showed the posteriorly herniated right lower lobe crossing the midline to extend into the left hemithorax farther beyond the descending thoracic aorta through the space between the esophagus and the aorta. This anatomical configuration resulted in a characteristic radiographic finding of a radiolucent area with a convex lateral border and a vertical medial border in the left lower lung zone, revealing a tongue-like projection on CT and MRI.
CONCLUSION
Posterior lung herniation occurs in unilateral left lung agenesis/aplasia. Approximately 70% of the cases of posterior lung herniation reveal a unique radiolucent tongue-like projection in the left lower lung zone on imaging studies, which is caused by the extension of the posteriorly herniated right lung farther beyond the descending aorta.
Topics: Abnormalities, Multiple; Child; Female; Humans; Infant; Lung; Lung Diseases; Male; Tomography, X-Ray Computed
PubMed: 34269531
DOI: 10.3348/kjr.2021.0155 -
Annals of Palliative Medicine Feb 2021Endoscopic submucosal dissection (ESD) under general anesthesia in left lateral position may lead to transient impairment of pulmonary function. We used electrical... (Observational Study)
Observational Study
BACKGROUND
Endoscopic submucosal dissection (ESD) under general anesthesia in left lateral position may lead to transient impairment of pulmonary function. We used electrical impedance tomography (EIT), an increasingly implied non-invasive instrument for bedside real-time monitoring regional changes in ventilation, to assess the changes of regional lung aeration and ventilation in patients undergoing ESD.
METHODS
Twenty-two patients scheduled for elective ESD under mechanical ventilation in left lateral position were studied. We acquired 2-min EIT records at four time points: (M1) baseline, before induction of anesthesia, (M2) after the start of mechanical ventilation and before surgery, (M3) after surgery and before extubation, and (M4) after extubation and before leaving operation room, respectively. To quantify regional changes in lung ventilation, we calculated the ventilation proportion of left and right lung regions. Possible changes in lung aeration were detected by changes in end-expiratory lung impedance (EELI). Global inhomogeneity index (GI) was also analyzed.
RESULTS
After tracheal intubation in the left lateral position, left lung showed a lower ventilation proportion (M1, 49.6% vs. M2, 36.2% P<0.05), a reduction in EELI {∆EELI -87 [-809; 253]} and a higher GI index value (M1, 0.29±0.09 vs. M2, 0.41±0.12, P<0.05), while right lung showed a higher ventilation proportion (M1, 50.4% vs. M2, 63.8%, P<0.05) and an increase in EELI {∆EELI 161 [-952; 1,905]}. During ESD operation, no changes in either regional ventilation distribution or GI index were observed. After extubation, the GI values in right and left lung were both returned to the level before anesthesia.
CONCLUSIONS
In patients with left lateral position undergoing ESD, left lung was characterized by decreased ventilation and more inhomogeneity while right lung was opposite after intubation. ESD procedure with carbon dioxide insufflation did not lead to significant changes in either regional ventilation or homogeneity. And the change of lung inhomogeneity during ESD procedure is transient.
Topics: Anesthesia, General; Electric Impedance; Humans; Lung; Respiration, Artificial; Tomography
PubMed: 33040550
DOI: 10.21037/apm-20-1029 -
Interactive Cardiovascular and Thoracic... Jul 2022Boyden's triad of the right lung was first proposed in 2021. Here, we report 5 cases of this malformation found in the left lung.
OBJECTIVES
Boyden's triad of the right lung was first proposed in 2021. Here, we report 5 cases of this malformation found in the left lung.
METHODS
A total of 5280 patients with pulmonary lesions underwent three-dimensional computed tomography bronchography and angiography between January 2019 and January 2021, prior to surgery; 5 cases of this malformation were identified in the left lung. Bronchovascular patterns were analysed in each patient.
RESULTS
The incidence rate of Boyden's triad in the left lung was 0.1%. This malformation was further divided into B3 on B4+5 type and B3 on B4 type. In B3 on B4+5 type, B3 was shifted downwards on the common trunk of B4+5, and A3 arose from the common trunk of A4+5 running alongside B3. In B3 on B4 type, B3 was shifted downwards on B4. A4 and A5 appeared separately. A3 arose from A4, running alongside B3; A5 arose from the common trunk of A8 - 10, and there was also an extraordinary 'posterior vein' (V. post): V1+2c. The incidence of V. post was 0.17%. An additional 'fissure' lies longitudinally between S1+2 and S3+4+5, nearly perpendicular to the oblique fissure, dividing the upper lobe into 'two lobes'.
CONCLUSIONS
The B3 downwards-shifting malformation can be found on both lungs, and this is the first description of Boyden's triad in the left lung; it appears to be much rarer than that in the right lung, with some accompanying unique variations.
Topics: Bronchography; Humans; Lung; Tomography, X-Ray Computed
PubMed: 35373821
DOI: 10.1093/icvts/ivac082 -
Scientific Reports May 2021Lung is a dose-limiting organ in radiotherapy. This may limit tumour control when effort is made in planning to limit the likelihood of radiation-induced lung injury...
Lung is a dose-limiting organ in radiotherapy. This may limit tumour control when effort is made in planning to limit the likelihood of radiation-induced lung injury (RILI). Understanding the factors that dictate susceptibility to radiation-induced pulmonary fibrosis will aid in the prevention and management of RILI, and may lead to more effective personalized radiotherapy treatment. As the interaction of regional and organ-level responses may shape the chronic consequences of RILI, we sought to characterise both aspects of the response in an ovine model. A defined volume of left pulmonary parenchyma was prescribed 5 fractions of 6 Gy within 14 days while the contralateral lung dose was constrained. Radiographic changes via computed tomography (CT) were documented to define differences in radio-exposed lung relative to non-exposed lung at d21, d63 and d171 (n = 2), and at d21, d147 and d227 (n = 2). Gross and histologic lung changes were evaluated in samples derived at necropsy examination to define the chronic pulmonary response to radiation. Irradiated lung demonstrated reduced radio-density and increased homogeneity as evidenced from texture based radiomic feature analysis, relative to the control lung. At necropsy, the radiation field was readily defined by pallor on the pleural surface, which was also evident on the cut surface of fixed lung specimens. The degree and homogeneity of pallor reflected the sparse presence of erythrocytes in alveolar septal capillaries of radiation-exposed lung. These changes contrasted with dilated and congested microvasculature in the contralateral control lung. Referencing data to measurements made in control lung volumes of sheep experiencing acute RILI indicated that interstitial collagen continues to deposit in the radio-exposed lung field. Overall lung vascularity increased during the chronic response, as evidenced by increased expression of endothelial cell marker (CD31); however, vascularity was consistently decreased in irradiated lung and was negatively correlated with lung collagen. Other organ-level responses included increased expression of alpha smooth muscle actin (ASMA), increased numbers of proliferating cells (Ki67 positive), and cells expressing the dendritic cell-lysosomal associated membrane protein (DC-LAMP) antigen. The chronic response to RILI in this model is effected at both the whole organ and local lung level. Whilst the long-term consequences of exposure to radiation involved the continued deposition of collagen in the radiation field, organ-level responses also included increased vascularization and increased expression of ASMA, Ki67 and DC-LAMP. Interrupting the interplay between these aspects may influence susceptibility to pulmonary fibrosis after radiotherapy. We advocate for the importance of large animal model systems in pursuing these opportunities to target local, organ-level and systemic mechanisms in parallel within the same subject over time.
Topics: Animals; Disease Models, Animal; Female; Lung; Neoplasms; Radiation Pneumonitis; Radiotherapy; Sheep
PubMed: 33953285
DOI: 10.1038/s41598-021-88863-8 -
The European Respiratory Journal Oct 2006Diffuse panbronchiolitis (DPB) is an idiopathic inflammatory disease, well recognised in Japan and principally affecting the respiratory bronchioles, causing a... (Review)
Review
Diffuse panbronchiolitis (DPB) is an idiopathic inflammatory disease, well recognised in Japan and principally affecting the respiratory bronchioles, causing a progressive suppurative and severe obstructive respiratory disorder. If left untreated, DPB progresses to bronchiectasis, respiratory failure and death. It was first described in the early 1960s. Subsequently, in 1969, the disease was named DPB to distinguish it from chronic bronchitis. "Diffuse" refers to the distribution of the lesions throughout both lungs, and "pan-" refers to the involvement of inflammation in all layers of the respiratory bronchioles. The distinctive imaging and histological features, the coexisting sinusitis, and the isolation of Haemophilus influenzae and Pseudomonas aeruginosa in the sputum enhance disease recognition. Histologically, DPB is characterised by chronic inflammation, localised mainly in the respiratory bronchioles and adjacent centrilobular regions, with characteristic interstitial accumulation of foamy histiocytes, neutrophils and lymphocyte infiltration. Neutrophils and T-lymphocytes, particularly CD8+ cells, together with the cytokines interleukin-8 and macrophage inflammatory protein-1, are believed to play key roles in the development of DPB. A significant improvement in the prognosis of this potentially fatal disease has been recently reported thanks to the use of long-term therapy with macrolide antibiotics, the effect of which is attributed to an anti-inflammatory and immunoregulatory action.
Topics: Anti-Bacterial Agents; Erythromycin; Humans; Lung; Lung Diseases, Interstitial; Macrolides; Radiography; Respiratory Function Tests
PubMed: 17012632
DOI: 10.1183/09031936.06.00131805