6 beta-hydroxycortisol in serum and urine as determined by enzyme immunoassay on microtitre plates.

1986 ◽  
Vol 32 (11) ◽  
pp. 2094-2097 ◽  
Author(s):  
A Zhiri ◽  
H A Mayer ◽  
V Michaux ◽  
M Wellman-Bednawska ◽  
G Siest
Keyword(s):  
Detection Limit ◽  
Healthy Volunteers ◽  
Enzyme Immunoassay ◽  
Oral Contraceptives ◽  
Excretion Rate ◽  
Routine Procedure ◽  
Mean Values ◽  
Analytical Recovery ◽  
Collection Period ◽  
Serum And Urine

Abstract We modified our previous enzyme immunoassay (Clin Chim Acta 1986;157:267-76) for estimating 6 beta-hydroxycortisol (6 beta-OHF) to provide a more routine procedure for measuring it in urine and to increase sensitivity for its measurement in serum. Precision, analytical recovery, specificity, and detection limit are reported. 6 beta-OHF and 17-hydroxycorticosteroids in 24-h and 4-h (08:00-12:00 h) urine collections from healthy volunteers showed no significant day-to-day differences in excretion rate for either collection period. Mean values for 6 beta-OHF in serum of men, women, and women taking oral contraceptives showed no significant differences among these groups.

scholarly journals Development of enzyme immunoassay for endogenous ouabain-like compound in human plasma

1997 ◽  
Vol 43 (5) ◽  
pp. 715-722 ◽  
Author(s):  
Steven Harwood ◽  
John A Little ◽  
Gerard Gallacher ◽  
David Perrett ◽  
Raymond Edwards ◽  
...  
Keyword(s):  
Detection Limit ◽  
Healthy Volunteers ◽  
Enzyme Immunoassay ◽  
Human Plasma ◽  
Hplc Analysis ◽  
Cross Reactivity ◽  
Standard Curve ◽  
Endogenous Ouabain ◽  
Endogenous Steroid ◽  
Hplc Study

Abstract Widespread evidence supports the existence of an endogenous digitalis-like compound in mammals. We report here the development of a novel enzyme immunoassay for ouabain that, in conjunction with a detailed HPLC study, identifies a ouabain-like compound (OLC) in extracted human plasma. The assay is sensitive—minimum detection limit for OLC 37 pmol/L (11 pmol/L in plasma)—and has a working range (between-assay CV <10%) of 180–10 000 pmol/L (54–3000 pmol/L in plasma). Mean recoveries of ouabain added to plasma ranged from 90% to 100%, and plasma extracts diluted in parallel to the standard curve. Plasma OLC concentrations in 10 healthy volunteers averaged 92 pmol/L (range 55–168), assuming 100% cross-reactivity of OLC in the ouabain assay. HPLC analysis with two distinct chromatographic conditions demonstrated that endogenous human plasma OLC co-eluted with authentic ouabain. The enzyme immunoassay is rapid and easy to perform and will support further investigation of the nature of this controversial endogenous steroid.

Highly sensitive enzyme immunoassay of proinsulin immunoreactivity with use of two monoclonal antibodies

1993 ◽  
Vol 39 (10) ◽  
pp. 2146-2150 ◽  
Author(s):  
L L Kjems ◽  
M E Røder ◽  
B Dinesen ◽  
S G Hartling ◽  
P N Jørgensen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Detection Limit ◽  
Human Serum ◽  
Enzyme Immunoassay ◽  
Healthy Subjects ◽  
Sandwich Elisa ◽  
C Peptide ◽  
Peptide Antibody ◽  
Analytical Recovery ◽  
Highly Sensitive

Abstract A highly sensitive two-site sandwich ELISA measuring total proinsulin immunoreactive material in serum or plasma was developed. The assay was based on two monoclonal antibodies, an anti-C-peptide antibody bound to a microtest plate and a biotin-labeled anti-insulin antibody. The detection limit (3 SD above zero value) in buffer was 0.05 pmol/L, corresponding to 0.25 pmol/L in human serum (diluted 1:5). The linear calibrator range was 0.05-20 pmol/L. Interassay CVs were 4.7% at a median (range) of 2.3 pmol/L (1.4-2.8 pmol/L, n = 8), 6.7% at 5.1 pmol/L (3.3-8.0 pmol/L, n = 8), and 8.7% at 10.0 pmol/L (8-12 pmol/L, n = 10). Mean analytical recovery of added human proinsulin (hPI) (2, 5, and 10 pmol/L) to serum was 84% (range 68-128%, n = 9). Human insulin and human C-peptide did not cross-react at 5000 and 10,000 pmol/L, respectively. The four major proinsulin conversion intermediates reacted 65-99%: split(32-33)hPI 74%, des-(31,32)hPI 65%, split(65-66)hPI 78%, and des(64,65)hPI 99%. All serum values from 38 fasting healthy subjects were above the detection limit: median (range) 4.0 (2.1-12.6) pmol/L.

Reference Values of Serum and Urine Creatinine, and of Creatinine Clearance by a New Enzymatic Method

1992 ◽  
Vol 29 (5) ◽  
pp. 523-528 ◽  
Author(s):  
O Sugita ◽  
K Uchiyama ◽  
T Yamada ◽  
T Sato ◽  
M Okada ◽  
...  
Keyword(s):  
Creatinine Clearance ◽  
Reference Intervals ◽  
Japanese Children ◽  
Mean Values ◽  
Urine Creatinine ◽  
Coefficients Of Variation ◽  
Analytical Recovery ◽  
Enzymatic Procedure ◽  
Serum And Urine

A new, totally enzymatic procedure for the determination of creatinine in serum and urine, using creatinine amidohydrolase, creatine amidinohydrolase, sarcosine oxidase and formaldehyde dehydrogenase is described. The assay was adapted to a discontinuous analyser with each analysis requiring only 20 μL of serum or 3 μL of urine. Analytical recovery of creatinine in serum and urine averaged 100·6%. Within-run and between-run precision studies gave coefficients of variation of 1·1% and 1·8%, respectively, for a serum with mean values of 83 μmol/L (9·4 mg/L) creatinine. Creatinine concentrations in serum and urine were measured by this procedure, in Japanese children and adults. The reference intervals for serum creatinine concentrations in adults were 55–96 μmol/L (6·2–10·9 mg/L) in men and 40–66 μmol/L (4·5–7·5 mg/L) in women, and for urine, 9·46–19·01 mmol/day (1070–2150 mg/day) in men and 6·75–10·61 mmol/day (764–1200 mg/day) in women. The reference intervals of creatinine clearance were 88·0–176·4 mL/min in men and 75·7–173·0 mL/min in women.

A receptor-antibody sandwich assay for teicoplanin.

1987 ◽  
Vol 33 (9) ◽  
pp. 1615-1618 ◽  
Author(s):  
A Corti ◽  
L Cavenaghi ◽  
E Giani ◽  
G Cassani
Keyword(s):  
Detection Limit ◽  
Dose Response ◽  
Response Curve ◽  
Synthetic Analog ◽  
Sandwich Complexes ◽  
Sandwich Assay ◽  
Receptor Antibody ◽  
Microtiter Plates ◽  
Analytical Recovery ◽  
Biological Target

Abstract We have developed a new method for quantifying teicoplanin in complex matrixes, a receptor-antibody sandwich assay (RASA). The method is based on bioselective adsorption of teicoplanin onto microtiter plates coated with albumin-epsilon-aminocaproyl-D-alanyl-D-alanine, a synthetic analog of its biological target, and reaction with anti-teicoplanin antibodies. The sandwich complexes are detected by incubation with peroxidase-labeled goat antibodies to rabbit IgGs and chromogenic reaction with o-phenylenediamine. The dose-response curve was linear for teicoplanin concentrations in the range from 0 to 0.15 mg/L. We used the assay to measure teicoplanin concentrations in various biological matrixes. Analytical recovery from serum was 99.5%, the interassay CV was 5.1%, and the detection limit was 30 micrograms/L (P less than 0.01). Mean analytical recoveries from other biological specimens were 98% from ascitic fluid, 100% from pleuric liquid, 104.8% from prostate homogenate, and 98.5% from bronchial expectorate.

scholarly journals The use of a neck brace does not influence visual vertical perception

2011 ◽  
Vol 69 (3) ◽  
pp. 509-512 ◽  
Author(s):  
Martha Funabashi ◽  
Natya N.L. Silva ◽  
Luciana M. Watanabe ◽  
Taiza E.G Santos-Pontelli ◽  
José Fernando Colafêmina ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Afferent Input ◽  
Subjective Visual Vertical ◽  
Sensory Receptors ◽  
Ocular Torsion ◽  
Vertical Orientation ◽  
Mean Values ◽  
Visual Vertical ◽  
The Mean

Subjective visual vertical (SVV) evaluates the individual's capacity to determine the vertical orientation. Using a neck brace (NB) allow volunteers' heads fixation to reduce cephalic tilt during the exam, preventing compensatory ocular torsion and erroneous influence on SVV result. OBJECTIVE: To analyze the influence of somatosensory inputs caused by a NB on the SVV. METHOD: Thirty healthy volunteers performed static and dynamic SVV: six measures with and six without the NB. RESULTS: The mean values for static SVV were -0.075º±1.15º without NB and -0.372º±1.21º with NB. For dynamic SVV in clockwise direction were 1.73º±2.31º without NB and 1.53º±1.80º with NB. For dynamic SVV in counterclockwise direction was -1.50º±2.44º without NB and -1.11º±2.46º with NB. Differences between measurements with and without the NB were not statistically significant. CONCLUSION: Although the neck has many sensory receptors, the use of a NB does not provide sufficient afferent input to change healthy subjects' perception of visual verticality.

Assay of magnesium in serum and urine with use of only one enzyme, isocitrate dehydrogenase (NADP+)

1995 ◽  
Vol 41 (9) ◽  
pp. 1302-1305 ◽  
Author(s):  
T Fujita ◽  
Y Kawakami ◽  
S Kohda ◽  
S Takata ◽  
Y Sunahara ◽  
...  
Keyword(s):  
Atomic Absorption ◽  
Isocitrate Dehydrogenase ◽  
Atomic Absorption Spectrophotometry ◽  
Magnesium Ion ◽  
Absorption Spectrophotometry ◽  
Metal Chelating ◽  
Analytical Recovery ◽  
Enzymatic Reduction ◽  
Chelating Reagents ◽  
Serum And Urine

Abstract We report a method for assaying magnesium in serum and urine involving only one enzyme, isocitrate dehydrogenase (NADP+)(EC 1.1.1.42), which requires magnesium ion for activity. The enzymatic reduction of NADP+ by isocitrate increases in rate linearly up to at least 20 mmol/L magnesium in the presence of appropriate concentrations of the two metal-chelating reagents, EDTA and glycol ether diamine-N,N,N',N'-tetraacetate. Within-run (n = 20) CVs and day-to-day (n = 10) CVs for sera are < or = 1.5% and < or = 2.6%, respectively. Analytical recovery of magnesium in sera averages 96-100%. This method is not affected by bilirubin, hemoglobin, or lipemia. The method (y) gives the following results correlating with atomic absorption spectrophotometry (x): y = 1.03x + 0.06 mmol/L (n = 62, r = 0.995, Sylx = 0.03) for sera, and y = 1.03x - 0.10 mmol/L (n = 62, r = 0.989, Sylx = 0.19) for urines; with the calmagite method (x): y = 0.99x + 0.04 mmol/L (n = 62, r = 0.991, Sylx = 0.03) for sera, and y = 0.98x + 0.03 mmol/L (n = 62, r = 0.999, Sylx = 0.02) for urines.

Determination of creatinine in serum and urine by a rapid liquid-chromatographic method

1990 ◽  
Vol 36 (6) ◽  
pp. 830-836 ◽  
Author(s):  
R Paroni ◽  
C Arcelloni ◽  
I Fermo ◽  
P A Bonini
Keyword(s):  
Signal To Noise Ratio ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Internal Standardization ◽  
Assay Precision ◽  
Fuller’S Earth ◽  
Liquid Chromatographic ◽  
Specific Evaluation ◽  
Serum And Urine

Abstract We describe an HPLC ion-pair procedure for rapid and specific evaluation of creatinine in serum and urine. We used a 15 cm X 4.6 mm ODS column with a 50/50 (by vol) mixture of sodium decanesulfonic acid (10 mmol/L, pH 3.2) and methanol and measured absorbance at 236 nm. Serum (100 microL) or 30-fold-diluted urine (100 microL) was added to 400 microL of acetone. After centrifugation, the supernates (300 microL) were dried, reconstituted with the mobile phase, and injected into the HPLC. Assay precision was tested for concentrations of 10, 29, and 130 mg/L and yielded, respectively, 3.1%, 2.1%, and 1.1% for within-day CV and 2.8%, 2.1%, and 2.2% for total CV. Analytical recovery was 102 (+/- 6.7%). Linearity was demonstrated in the 0-200 mg/L range for serum and 0-3.5 g/L range for urine (r greater than or equal to 0.999). The detection limit for creatinine (signal-to-noise ratio = 3) was 0.5 mg/L. We used cimetidine for internal standardization. Correlation was good between this procedure and the Jaffé kinetic, the enzymatic (creatinine amidohydrolase), and the Fuller's earth alkaline picrate methods.

Solid-phase enzymoimmunoassay for osteocalcin in human serum or plasma, with use of a monoclonal antibody.

1989 ◽  
Vol 35 (10) ◽  
pp. 2087-2092 ◽  
Author(s):  
M J Power ◽  
P F Fottrell
Keyword(s):  
Monoclonal Antibody ◽  
Detection Limit ◽  
Horseradish Peroxidase ◽  
Human Serum ◽  
Solid Phase ◽  
Sample Volume ◽  
Microtiter Plates ◽  
Analytical Recovery ◽  
Peroxidase Conjugate

Abstract In this solid-phase enzymoimmunoassay on microtiter plates for osteocalcin in serum or plasma, we use an osteocalcin-horseradish-peroxidase conjugate and a monoclonal antibody raised against bovine osteocalcin. We thoroughly standardized the assay for measurement of osteocalcin in both serum and plasma, demonstrating independence of sample volume, and determining the analytical recovery and within-and between-assay CVs. The detection limit was between 0.6 and 1.1 micrograms/L and the ED50 was 16 micrograms/L for a 5-microL sample volume. The intra-assay CV over the range 3 to 74 micrograms/L was less than or equal to 15%. The interassay CV over the range 3.6 to 46 micrograms/L was less than or equal to 16%. Results by this assay and by an in-house radioimmunoassay in which the same monoclonal antibody was used correlated well (r2 = 0.948). Osteocalcin concentrations in serum and plasma as measured with the present assay agreed well with published values.

Homogeneous enzyme immunoassay for tobramycin evaluated and compared with a radioimmunoassay.

1982 ◽  
Vol 28 (6) ◽  
pp. 1370-1374 ◽  
Author(s):  
J Woo ◽  
M A Longley ◽  
D C Cannon
Keyword(s):  
Enzyme Immunoassay ◽  
Room Temperature ◽  
Correlation Study ◽  
Stability Study ◽  
Data Handling ◽  
Handling System ◽  
Analytical Recovery ◽  
Assay Precision ◽  
Absorbance Data ◽  
Homogeneous Enzyme Immunoassay

Abstract We evaluated a commercially available homogeneous enzyme immunoassay (EMIT, Syva Co.) for tobramycin against a reference radioimmunoassay (RIA) method. Between-assay precision (CV) was 2.9% at 6.2 mg/L and 3.0% for values in the range of 1.0-7.6 mg/L. Accuracy based on a recovery experiment (1.0-13.0 mg/L) yielded an analytical recovery of 88-112%. A correlation study with 75 sera from patients on tobramycin therapy showed that EMIT = 0.984 RIA - 0.0808, r = 0.993. Neither the EMIT nor the RIA procedure was affected by the presence of gentamicin, amikacin, and vancomycin. Absorbance data from the EMIT system calculated with the conventional RIA logit-log algorithm correlate well with results generated by the Syva data-handling system (logit-log = 1.077 Syva - 0.318, r = 0.998). A reagent stability study indicated that the EMIT reagents, once reconstituted, remain stable for at least 17 days when stored at refrigerated temperatures, or 11 days if stored at room temperature, thus enabling frequent "stat" assays without the need to prepare a calibration curve each time.

Radioreceptor Assay for Quantifying FK-506 Immunosuppressant in Whole Blood

1992 ◽  
Vol 38 (7) ◽  
pp. 1307-1310 ◽  
Author(s):  
J N Murthy ◽  
Y Chen ◽  
V S Warty ◽  
R Venkataramanan ◽  
J G Donnelly ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Enzyme Immunoassay ◽  
Whole Blood ◽  
Binding Protein ◽  
Radioreceptor Assay ◽  
Fk 506 ◽  
Blood Concentrations ◽  
Chromatographic Columns ◽  
Analytical Recovery

Abstract We describe a quantitative radioreceptor assay (RRA) for quantifying FK-506 in whole blood. FK-506 extracted from whole blood with a cyclohexyl-sorbent column competes with [3H]dihydro-FK-506 for binding to a partially purified preparation of FK-506 binding protein (FK-BP). Free and protein-bound FK-506 are separated on LH 20 Sephadex chromatographic columns. We compared the results of this method with those of an enzyme immunoassay that uses a monoclonal antibody: r = 0.97, Sy/x = 0.039. Between-day precisions (CV) at FK-506 concentrations of 8 and 17 micrograms/L were 9.2% and 8.2%, respectively. Within-run precisions were 5.9%, 8.1%, and 9.4%, respectively, at 4, 8, and 15 micrograms/L. Analytical recovery, evaluated at 5, 10, 15, 20, and 25 micrograms/L for FK-506 added to whole blood, ranged from 98% to 103%. The assay can reliably quantify FK-506 blood concentrations between 1.0 and 25 micrograms/L.

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