Mucus Clearance: An Experimental and Numerical Study

Author(s):  
Yingying Hu ◽  
Shiyao Bian ◽  
James B. Grotberg

Mucus in a human lung has non-Newtonian properties such as shear-thinning, yield stress, and viscoelasticity. Rheological changes of mucus may greatly affect its ability to function as a lubricant, selective barrier, and the body’s first line of defense against infection (Lai 2009). Patients with COPD, asthma, or cystic fibrosis often have mucus hyper-secretion. Mucus plugging can cause total airway obstruction (Kant 2007). If mucus is too thick, for example in severe bronchitis or cystic fibrosis where the sputum viscosity can be more than 105 times that of water, patients experience great difficulty in mucus clearance, resulting in bacterial overgrowth (Lai 2009). The understanding of the mechanisms involved in mucus clearance is far from complete. For instance, the relation is not known between the non-Newtonian properties of the mucus layer and ciliary function in thickened mucus (Button 2008).

2008 ◽  
Vol 54 (8) ◽  
pp. 1730-1735 ◽  
Author(s):  
Arne R. J. Schneider ◽  
Stefanie Klueber ◽  
Hans-Georg Posselt ◽  
Benjamin Funk ◽  
Lydia Murzynski ◽  
...  

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3142
Author(s):  
Alissa Groenendijk ◽  
Filippo Spreafico ◽  
Ronald R. de Krijger ◽  
Jarno Drost ◽  
Jesper Brok ◽  
...  

In high-income countries, the overall survival of children with Wilms tumors (WT) is ~90%. However, overall, 15% of patients experience tumor recurrence. The adverse prognostic factors currently used for risk stratification (advanced stage, high risk histology, and combined loss of heterozygosity at 1p and 16q in chemotherapy-naïve WTs) are present in only one third of these cases, and the significance of these factors is prone to change with advancing knowledge and improved treatment regimens. Therefore, we present a comprehensive, updated overview of the published prognostic variables for WT recurrence, ranging from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. Improved first-line treatment regimens based on clinicopathological characteristics and advancing knowledge on copy number variations unveil the importance of further investigating the significance of biological markers for WT recurrence in international collaborations.


2020 ◽  
Author(s):  
R.J. Marsh ◽  
C. Ng ◽  
G. Major ◽  
D.W. Rivett ◽  
A. Smyth ◽  
...  

AbstractBackgroundPatients with cystic fibrosis (CF) are characterised by abnormalities of the intestinal tract relating to gut motility and physiological issues, with daily symptoms of disease including abdominal pain, flatulence, bloating, and constipation. With improvements in respiratory outcomes, a shift in disease manifestations has highlighted the prevalence of the gastrointestinal-related problems associated with CF, yet most therapies currently in clinical use for the gut symptoms of CF have been repurposed from other disease indications and have not been developed with a knowledge of the mechanisms underpinning gastrointestinal disease in CF. Increased attention towards the role of intestinal inflammation and microbial dysbiosis in the CF population warrants a comprehensive knowledge of these aspects alongside the increased luminal fat content, dysmotility, and small intestinal bacterial overgrowth (SIBO) resultant of the primary consequences of CFTR dysfunction (disrupted fluid secretion and pancreatic insufficiency), and how they contribute towards the intestinal complications of CF disease.Methods and Study DesignWe will conduct a systematic review to comprehensively address our current understanding of the primary consequences of CFTR dysfunction, and their subsequent secondary effects that contribute towards the disruption of gut motility, health, and associated symptoms in the CF intestine. Databases searched will include PubMed, CINAHL, MEDLINE and the Cochrane library from 1939 until a specified date of last search, alongside clinical trial databases for ongoing studies. Search strategies will include various terminology that relates to the primary mechanistic defects of CF, postulated secondary effects of such defects, and symptoms experienced in patients. A full search strategy is outlined in appendix B. One reviewer will apply an inclusion criterion to obtained abstracts. Following agreement from a second reviewer, full-text articles will be sought, and data will be extracted from relevant articles. Disagreements will be resolved with a third reviewer. The quality of data will be assessed by the GRADE criteria. Data will be used to present a narrative, and where possible, quantitative synthesis.DiscussionThis systematic review will discuss our current understanding of the underpinning mechanisms of the persisting abnormalities in gut health and motility within CF, addressing potential intricate relationships that further contribute to disease progression within the intestinal tract. Furthermore, we will identify current gaps in the literature to propose directions for future research. A comprehensive understanding of these aspects in relation to intestinal abnormalities will aid future clinical directions.


Author(s):  
Chenbing Wu ◽  
Weiwei Yan ◽  
Chen Rou ◽  
Yang Liu ◽  
Guozhan Li

2019 ◽  
Vol 53 (4) ◽  
pp. 1801793 ◽  
Author(s):  
Tiffany J. Dwyer ◽  
Evangelia Daviskas ◽  
Rahizan Zainuldin ◽  
Jordan Verschuer ◽  
Stefan Eberl ◽  
...  

Exercise improves mucus clearance in people without lung disease and those with chronic bronchitis. No study has investigated exercise alone for mucus clearance in cystic fibrosis (CF). The aim of this study was to compare the effects of treadmill exercise to resting breathing and airway clearance with positive expiratory pressure (PEP) therapy on mucus clearance in adults with CF.This 3-day randomised, controlled, crossover trial included 14 adults with mild to severe CF lung disease (forced expiratory volume in 1 s % predicted 31–113%). Interventions were 20 min of resting breathing (control), treadmill exercise at 60% of the participant's peak oxygen consumption or PEP therapy (including huffing and coughing). Mucus clearance was measured using the radioaerosol technique and gamma camera imaging.Treadmill exercise improved whole lung mucus clearance compared to resting breathing (mean difference 3%, 95% CI 2–4); however, exercise alone was less effective than PEP therapy (mean difference −7%, 95% CI −6– −8). When comparing treadmill exercise to PEP therapy, there were no significant differences in mucus clearance from the intermediate and peripheral lung regions, but significantly less clearance from the central lung region (likely reflecting the huffing and coughing that was only in PEP therapy).It is recommended that huffing and coughing are included to maximise mucus clearance with exercise.


1999 ◽  
Vol 14 (3) ◽  
pp. 678 ◽  
Author(s):  
M. Robinson ◽  
E. Daviskas ◽  
S. Eberl ◽  
J. Baker ◽  
H-K Chan ◽  
...  

RSC Advances ◽  
2019 ◽  
Vol 9 (68) ◽  
pp. 40176-40183
Author(s):  
Jackson R. Hall ◽  
Sara E. Maloney ◽  
Haibao Jin ◽  
James B. Taylor ◽  
Mark H. Schoenfisch

Nitric oxide diffusion monitored through artificial sputum medium using an adaptable diffusion cell and released from donor through human lung tissue.


1977 ◽  
Vol 42 (5) ◽  
pp. 761-766 ◽  
Author(s):  
A. Giordano ◽  
C. K. Shih ◽  
D. S. Holsclaw ◽  
M. A. Khan ◽  
M. Litt

Tracheal mucociliary clearance was studied by a radioisotope technique in pentothal-anesthetized beagles in the control, atropinized, or dehydrated state. Mucus collected from a tracheal pouch in each dog was used for in vitro bullfrog (Rana cantesbiana) palate clearance studies and compared to the in vivo clearance rates. In all three experimental states, there was a significant correlation between in vivo and in vitro rates, suggesting that tracheal pouch mucus is a good model for investigating the mucociliary flow properties of intact airway mucus. When compared to matched controls, atropine appeared to cause a slowing of the in vivo clearance rate but not of the in vitro rate. Dehydration had no effect on either. The appropriateness of the frog palate method in the study of human respiratory disease (e.g., chronic bronchitis, cystic fibrosis) as well as its potential as an objective method of assessing the effects of various therapeutic modalities in these diseases is discussed.


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