title: Electron microscopy of mucin from sputum in chronic obstructive bronchitis.
abstract: Sputum from patients with chronic obstructive bronchitis has been fractionated on Sepharose columns after treatment with urea 6 mol/l at pH 12.5 followed by neutralization. The "mucin" fraction, which contained 70% carbohydrate and 30% protein was studied in the electron microscope after staining with phosphotungstic acid. Positively stained, thread-like, irregular contours of the mucin molecules could be demonstrated with lengths varying from 2,000 to 5,000 nm, corresponding to molecular weights between 2 X 10(6) and 6 X 10(6). This correlates fairly well with estimates from the literature of the size of these molecules.
mesh_terms: D001991:Bronchitis / Q000378:metabolism*; D002241:Carbohydrates / Q000032:analysis; D005591:Chemical Fractionation; D002908:Chronic Disease; D006801:Humans; D008854:Microscopy, Electron; D008970:Molecular Weight; D009077:Mucins / Q000032:analysis* / Q000302:isolation & purification; D011506:Proteins / Q000032:analysis; D013183:Sputum / Q000032:analysis*
chemical_list: D002241:Carbohydrates; D009077:Mucins; D011506:Proteins