Linked Life Data

8067919

Source:http://linkedlifedata.com/resource/pubmed/id/8067919

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1994-9-22
pubmed:abstractText
This study examined in detailed the pH response of microcosm plaque biofilms to the application of 500 mmol/l urea, and the effect of modifying the flow rate of BMM (a basal medium containing 0.25% mucin). Microcosm plaques were cultured from the mixed salivary bacteria in a multi-plaque 'artificial mouth' supplied continuously with BMM at 3.6 ml/h per plaque, and periodically with sucrose (5 or 10%). Urea (500 mmol/l) induced a pH response that was the inverse of the Stephan pH curve induced by sucrose. In thicker plaques the ureolytic pH response was delayed and slower. With no BMM flow, the urea-induced pH curve reached a maximum and then slowly decreased indicating loss of ammonia. A flow of BMM reduced the magnitude of the pH response. Urea dilution explained (r2 = 0.97) the reduction in the maximum rate of pH rise caused by an increasing BMM flow. There were, however, additional flow-rate effects on the magnitude of the pH rise, the curve areas and the maximum rate of pH decrease back to the resting pH. These effects were greatest at low BMM flow rates, indicating that ammonia clearance may be limited at higher flow rates by the rate of intraplaque diffusion and metabolism. Application of 50 instead of 500 mmol/l urea reduced the rate of pH rise about 10-fold, and the area of the curve about seven fold. Metabolism of arginine (50 mmol/l) generated only about half the pH response of the same amount of urea.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
D
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0003-9969
pubmed:author
pubmed:issnType
Print
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
497-505
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
The pH response to urea and the effect of liquid flow in 'artificial mouth' microcosm plaques.
pubmed:affiliation
Dental Research Unit, Wellington School of Medicine, University of Otago, New Zealand.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't