Interpretation of the mucous plug through sialendoscopy

We have previously noted that sequential extraction of an asthmatic mucous exudate with 6 M guanidinium chloride yielded a fraction of the mucins that were most resistant to solubilization and of high Mr [Sheehan, Richardson, Fung, Howard and Thornton (1995) Am. J. Respir. Cell Mol. Biol. 13, 748–756]. Here we show that this mucin fraction is dominated (at least 96% of the total) by the low-charge glycoform of the MUC5B gene product. Seen in the electron microscope the mucins appeared mainly as compact ‘island ’ structures composed of linear threads often emanating from globular ‘nodes ’ rather than the discrete linear threads more typical of mucins that we have previously described. The effect of reducing agents was as expected for other gel-forming mucins, i.e. reduced subunits or monomers of Mr 3×106) were produced within 15 min of treatment. Kinetic experiments on the cleavage of the intact mucins with the proteinase trypsin indicated two clear regimes of fragmentation. An initial rapid cleavage generated mucins ranging from Mr = 4×106 to 30×106 that in the electron microscope appeared as polydisperse threads (500–3000 nm in length), similar to normal and other respiratory mucins that we have previously characterized. A subsequent slower fragmentation over many hours yielded a major fragment of Mr 3×106 and length 200–600 nm, very similar in size and Mr to the subunits obtained by reduction. The results suggest that the MUC5B mucin is assembled, first into polydisperse linear threads, which are then linked together via a protein-mediated process. This might involve part of the mucin polypeptide or an as yet unidentified protein(s). The high proteinase susceptibility of the linkage suggests that it might be a point of control for mucin size and thus mucus rheology.

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Necrotizing Tracheobronchitis

PEDIATRICS ◽

10.1542/peds.78.6.1168 ◽

1986 ◽

Vol 78 (6) ◽

pp. 1168-1168

Author(s):

F. MIMOUNI ◽

E. T. BALLARD ◽

R. T. COTTON ◽

J. L. BALLARD

Keyword(s):

The Past ◽

Mucous Plug ◽

Necrotizing Tracheobronchitis

In Reply.— We thank Kirpalani et al for their interest in our article1 and their comments. We also read with interest their report,2 which was published while our article was in press, and which confirms that survival is possible after necrotizing tracheobronchitis. Furthermore, we speculate that many "mild" cases of necrotizing tracheobronchitis may have not been recognized in the past, when obstruction was relieved solely by suctioning, and the "mucous plug" was not examined histologically. Treatment of necrotizing tracheobronchitis will probably be the source of controversy in future years.

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The Case of the Mucous Plug

Hospital Practice ◽

10.1080/21548331.1971.11706050 ◽

1971 ◽

Vol 6 (6) ◽

pp. 136-137

Author(s):

William B. Seaman

Keyword(s):

Mucous Plug

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Airway Obstruction due to Mucous Plug after Endotracheal Intubation in Comatous Patient

Korean Journal of Anesthesiology ◽

10.4097/kjae.1980.13.4.426 ◽

1980 ◽

Vol 13 (4) ◽

pp. 426

Author(s):

Nak Seon Kim ◽

Choul Hong Park ◽

Inn Se Kim ◽

Suk Hee Lee

Keyword(s):

Airway Obstruction ◽

Endotracheal Intubation ◽

Mucous Plug

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Unilateral Absence of Ventilation and Perfusion Associated With a Bronchial Mucous Plug

Southern Medical Journal ◽

10.1097/00007611-198703000-00033 ◽

1987 ◽

Vol 80 (3) ◽

pp. 391-393 ◽

Cited By ~ 2

Author(s):

LOWELL E. VEREEN ◽

D KEITH PAYNE ◽

RONALD B. GEORGE

Keyword(s):

Mucous Plug ◽

Ventilation And Perfusion

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Flexible Minibronchoscopy in Children

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948709600605 ◽

1987 ◽

Vol 96 (6) ◽

pp. 645-649 ◽

Cited By ~ 12

Author(s):

Robert F. Ward ◽

James E. Arnold ◽

Gerald B. Healy

Keyword(s):

Pediatric Population ◽

Upper Airway ◽

Flexible Endoscopy ◽

Rigid Bronchoscopy ◽

Upper Aerodigestive Tract ◽

Treatment Plans ◽

Tracheal Disease ◽

Mucous Plug ◽

Airway Dynamics

Flexible endoscopy is assuming a role of increasing importance in the evaluation and diagnosis of upper aerodigestive tract disorders. With improved fiberoptic capabilities and miniaturization, these techniques are gaining in applicability to the pediatric population. At Children's Hospital, Boston, a newly designed Machida 1.9-mm bronchoscope has been employed in the evaluation of the upper airway. The use of this small caliber instrument has been investigated in 1) evaluation of endotracheal or tracheotomy tube position, thus decreasing the need for repeated chest radiographs to confirm location; 2) bedside evaluation of possible tracheal disease (eg, mucous plug, granuloma, tracheitis) in the intensive care unit patient to determine treatment plans and/or need for further rigid bronchoscopy, and 3) evaluation of airway dynamics in the awake patient. Our experience with the flexible fiberoptic minibronchoscope is reviewed, with a discussion of indications for its use, as well as possible limitations. Case studies are presented to demonstrate the usefulness of the instrument.

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