WordNet

permission to proceed; "the plane was given clearance to land"
the distance by which one thing clears another; the space between them

PrepTutorEJDIC

〈U〉〈C〉(…の)取り片付け,除去,掃除《+『of』+『名』》 / 〈U〉〈C〉(積荷の)通関手続き,(船の)出港免状 / (またclearance sale)〈C〉大棚ざらいの売出し / 〈U〉〈C〉(手形の)決済,(小切手の)現金化 / 〈U〉〈C〉(二つの物の間の)あき,余裕;(特に)道路面・川の面から橋げたまでの高さ / 〈U〉〈C〉秘密情報の使用許可;(秘密情報を扱う人の)信頼性調査;公安調査

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/11/19 15:30:19」(JST)

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Mucociliary clearance, also referred to as mucociliary apparatus or mucociliar clearance (MCC), derived from mucus, cilia (cilia of the tracheal surface epithelium in the respiratory tract ) and clearance describes the self-clearing mechanism of the bronchi.

The passage of airway in the respiratory tract that conducts air into the lungs main bronchi down to the final branchings of the respiratory tree (which act as the primary gas exchange units of the lung)alveoli are lined with a moist lining of the airway respiratory epithelium. On that, cilium is present, bearing hair-shaped structures on its surface (cilia). The cilia are surrounded by a thin fluid film of mucus. On top of that is a second viscous film of mucus, in which foreign particles and microorganisms get stuck. Within the thin fluid film of mucus the cilia act out movements coordinated in direction towards the pharynx. Thereby the viscous film of mucus including its freight is transported off in direction towards the mouth, where it is either swallowed or expelled via coughing.

Important for good mucociliary clearance are the number of cilia, their structure, activity, and coordinated movement. Optimum functionality of mucociliary clearance presuppose a temperature of 37 °C and an absolute humidity of 44 mg/dm³ corresponding to a relative humidity of 100%. Under the condition of insufficient temperature and humidity, after a short time the ciliary cells suspend their transport function. Under such circumstances, bacterial germinal colonization is facilitated. Pulmonary infections and damaging of the pulmonic tissues may be the consequence.

High humidity enhances the functionality of the mucociliary clearance. Two methods of supporting mucociliary clearance are the active and the passive respiratory gas humidification, which in particular are applied in mechanical ventilation.

References

M.A. Sleigh, J.R. Blake, N. Liron: The Propulsion of Mucus by Cilia. In: Am. Rev. Respir., Dis. 1988; 137: 726-41.
R. Williams, N. Rankin, T. Smith, et al.: Ralationship between humidity and temperature of inspired gas and the function of the airway mucosa. In: Crit. Care Med, 1996, Vol. 24, no11: 1920-1929.
R. Estes, G. Meduri: The Pathogenesis of Ventilator-Associated Pneumonia: 1. Mechanisms of Bacterial Transcolonization and Airway Inoculation. In: Intensive Care Medicine. 1995; 21: 365-383.

UpToDate Contents

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English Journal

Clinical value of measurement of pulmonary radioaerosol mucociliary clearance in the work up of primary ciliary dyskinesia.

Munkholm M1, Nielsen KG, Mortensen J.
EJNMMI research.EJNMMI Res.2015 Dec;5(1):118. doi: 10.1186/s13550-015-0118-y. Epub 2015 Jul 16.
BACKGROUND: We aimed to evaluate and define the general clinical applicability and impact of pulmonary radioaerosol mucociliary clearance (PRMC) on the work up of patients suspected of having primary ciliary dyskinesia (PCD). In addition, we wanted to evaluate the accuracy of the reference values us
PMID 26179226

A spatial model of fluid recycling in the airways of the lung.

Sharp K1, Crampin E2, Sneyd J3.
Journal of theoretical biology.J Theor Biol.2015 Oct 7;382:198-215. doi: 10.1016/j.jtbi.2015.06.050. Epub 2015 Jul 10.
The genetic disease cystic fibrosis (CF) is a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and results in viscous mucus and impaired mucociliary clearance leading to chronic recurring pulmonary infections. Although extensive experimental research has been conducte
PMID 26169010

Cilium height difference between strokes is more effective in driving fluid transport in mucociliary clearance: A numerical study.

Xu L1, Jiang Y.
Mathematical biosciences and engineering : MBE.Math Biosci Eng.2015 Oct 1;12(5):1107-26. doi: 10.3934/mbe.2015.12.1107.
Mucociliary clearance is the first line of defense in our airway. The purpose of this study is to identify and study key factors in the cilia motion that influence the transport ability of the mucociliary system. Using a rod-propel-fluid model, we examine the effects of cilia density, beating freque
PMID 26280187

Japanese Journal

The Effect of Cilia and the Mucociliary Clearance on Successful Drug Delivery

Gizurarson Sveinbjorn
Biological & pharmaceutical bulletin 38(4), 497-506, 2015-04
NAID 40020412051

The Effect of Cilia and the Mucociliary Clearance on Successful Drug Delivery

Gizurarson Sveinbjörn
Biological and Pharmaceutical Bulletin 38(4), 497-506, 2015
… Nasal mucociliary clearance is one of the most important factors affecting nasal delivery of drugs and vaccines. … For efficient mucociliary clearance, the interaction between the cilia and the nasal mucus needs to be well structured, where the mucus layer is a tri-layer: an upper gel layer that floats on the lower, more aqueous solution, called the periciliary liquid layer and a third layer of surfactants between these two main layers. …
NAID 130005062259

THE EFFECT OF CILIA AND THE MUCOCILIARY CLEARANCE ON SUCCESSFUL DRUG DELIVERY

Gizurarson Sveinbjörn
Biological and Pharmaceutical Bulletin advpub(0), 2015
… Nasal mucociliary clearance is one of the most important factors affecting nasal delivery of drugs and vaccines. … For efficient mucociliary clearance, the interaction between the cilia and the nasal mucus needs to be well structured, where the mucus layer is a tri-layer: an upper gel layer that floats on the lower, more aqueous solution, called the periciliary liquid layer and a third layer of surfactants between these two main layers. …
NAID 130004872300