Linked Life Data

2332080

Source:http://linkedlifedata.com/resource/pubmed/id/2332080

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-6-5
pubmed:abstractText
The authors aimed at developing a simplified method for the measurement of plasma free (unbound) steroids with ultrafiltration using Grace MPS device, and its clinical application. In this method, the movement of free steroids from plasma into ultrafiltrate was monitored with [14C]glucose added to the plasma. Plasma free steroids (cortisol, testosterone, estradiol and prednisolone) were measured as follows: Plasma was incubated with [14C]glucose (1.2 X 10(4) dpm/5 microliters) for 30 min at 37 degrees C. A 0.5 ml of aliquot was transferred to MPS device containing a single YMT membrane, and centrifuged at 1100 x g, at 37 degrees C, for 30 min in a 45 degree fixed angle head with the special temperature controller. After centrifugation, [14C] in 30 microliters of plasma and ultrafiltrate were counted. For the calculation of plasma free level, steroid concentration of ultrafiltrate measured directly by radioimmunoassay (RIA) was multiplied by the ratio of [14C]glucose (dpm) in plasma to [14C]glucose (dpm) in ultrafiltrate. For RIA of cortisol, testosterone and estradiol, commercially available kits were used, and for prednisolone, anti-prednisolone antibody developed in our laboratory was utilized. Since plasma free cortisol level showed a parallel increase with rise in temperature, strict temperature control during ultracentrifugation was required. On the other hand, the duration of centrifugation and the sample volume applied to MPS did not show any significant effect on the estimated values. Intraassay and interassay variations were 4.4% and 6.1% in free cortisol, 6.3% and 8.7% in free testosterone, 8.5% and 9.2% in free estradiol, and 8.8% and 9.9% in free prednisolone, respectively. The correlations between the plasma free steroid levels obtained by ultrafiltration (y) and equilibrium dialysis (x) were as follows, respectively: free cortisol; y = 1.16x + 0.017 (r = 0.95, n = 10), free testosterone; y = 1.17x-0.027 (r = 0.92, n = 10), free estradiol; y = 1.33x + 8.55 (r = 0.98, n = 12), free prednisolone; y = 1.03x + 1.00 (r = 0.98, n = 7). The mean plasma free cortisol levels and percent free fractions (%FF) were 1.16 +/- 0.40 (+/- SD) micrograms/dl and 10.9 +/- 3.0% in 10 control patients, 4.4 +/- 1.6 micrograms/dl and 15.6 +/- 3.3% in 8 patients with Cushing's syndrome, and 1.45 +/- 0.48 micrograms/dl and 5.9 +/- 2.4% in 11 normal pregnant women (10-40 weeks of pregnancy), respectively.(ABSTRACT TRUNCATED AT 400 WORDS)
pubmed:language
jpn
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0029-0661
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
113-26
pubmed:dateRevised
2011-7-27
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
[Measurement of plasma free cortisol, estradiol, testosterone and prednisolone by direct radioimmunoassay of ultrafiltrate and its clinical application].
pubmed:affiliation
Third Department of Internal Medicine, Gifu University School of Medicine, Japan.
pubmed:publicationType
Journal Article, English Abstract, Research Support, Non-U.S. Gov't