Linked Life Data

1450425

Source:http://linkedlifedata.com/resource/pubmed/id/1450425

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-1-7
pubmed:abstractText
Although red blood cell (RBC) geometry has been extensively studied by micropipette aspiration, the small size of RBC and pipettes vs. the optical resolution of light microscopy suggests the need to consider potential errors. The present study addressed such difficulties and investigated four specific problems: (1) use of exact equations to calculate RBC membrane area and volume; (2) calibration of the pipette internal diameter (PID); (3) correction for a noncylindrical pipette barrel; (4) diffraction distortion of the RBC image. The observed PID represents a cylinder lens enlargement that can be theoretically derived from the glass/buffer refractive index ratio (1.49/1.33 = 1.12). This enlargement was experimentally confirmed by: (1) studying pipettes bent to allow measurement through the barrel (horizontal) and at the orifice (vertical), with a resulting diameter ratio of 1.12 +/- 0.01; (2) and by replacing the surrounding buffer with immersion oil and hence abolishing the lens phenomenon (ratio = 1.12 +/- 0.02). In addition, use of aspirated oil droplets demonstrated a 3.2 +/- 0.2% error when the PID is focused at a sharp, maximum diameter. The average pipette cone angle was 1.49 +/- 0.09 degrees and varied considerably with pipette pulling procedures; calculated tongue geometry inside the pipette was affected by the noncylindrical pipette barrel. The RBC diffraction error, demonstrated by touching two aspirated cells held by opposing pipettes, was 0.091 +/- 0.002 microns. The PID, cone angle, and diffraction artifacts significantly (p < 0.001) affected calculated RBC geometry (average errors up to 5.4% for area and 9.6% for volume). Two new methods to calculate, rather than directly measure, the PID from images of a single RBC, during either osmotic or pressure manipulation, were evaluated; the osmotic method closely predicted the PID, whereas the pressure method markedly underestimated the PID. Our results thus confirm the need to consider the above-mentioned phenomena when determining RBC geometric parameters via micropipette aspiration.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
0340-4684
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
241-57; discussion 258-65
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Optical evaluation of red blood cell geometry using micropipette aspiration.
pubmed:affiliation
Department of Physiology and Biophysics, University of Southern California, School of Medicine, Los Angeles.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't