Simplified radioimmunoassay of bradykinin in human plasma.

1980 ◽  
Vol 26 (3) ◽  
pp. 429-432
Author(s):  
P S Verma ◽  
P E Lorenz ◽  
G E Sander
Keyword(s):  
Molecular Mass ◽  
Human Plasma ◽  
Normal Values ◽  
Normal Subjects ◽  
Single Step ◽  
Relative Molecular Mass ◽  
Blood Samples ◽  
Analytical Recovery ◽  
Assay Tube ◽  
The Mean

Abstract A greatly simplified radioimmunoassay for bradykinin in human plasma is described. Current techniques require multiple chromatographic steps or extraction procedures with analytical recoveries of bradykinin of often less than 60%. We present a method in which bradykinin is separated from components of higher relative molecular mass (including kininogens) in a single step, by use of a column of Sephadex G-25 medium (PD-10). The mean analytical recovery of tritiated bradykinin added to plasma is 85.5% (SD, 3.5%). The sensitivity of this radioimmunoassay is 25 pg per assay tube, equivalent to 125 ng per liter of plasma. Twenty to 30 blood samples may be completely processed and assayed within 6 h. As determined with this technique, concentrations of bradykinin in plasma from apparently normal subjects ranged from 2.5 to 5.2 microgram/L (mean 4.2, SD 1.1 microgram/L); these values are consistent with previously reported normal values.

Simplified radioimmunoassay of bradykinin in human plasma.

1980 ◽  
Vol 26 (3) ◽  
pp. 429-432 ◽  
Author(s):  
P S Verma ◽  
P E Lorenz ◽  
G E Sander
Keyword(s):  
Molecular Mass ◽  
Human Plasma ◽  
Normal Values ◽  
Normal Subjects ◽  
Single Step ◽  
Relative Molecular Mass ◽  
Blood Samples ◽  
Analytical Recovery ◽  
Assay Tube ◽  
The Mean

Abstract A greatly simplified radioimmunoassay for bradykinin in human plasma is described. Current techniques require multiple chromatographic steps or extraction procedures with analytical recoveries of bradykinin of often less than 60%. We present a method in which bradykinin is separated from components of higher relative molecular mass (including kininogens) in a single step, by use of a column of Sephadex G-25 medium (PD-10). The mean analytical recovery of tritiated bradykinin added to plasma is 85.5% (SD, 3.5%). The sensitivity of this radioimmunoassay is 25 pg per assay tube, equivalent to 125 ng per liter of plasma. Twenty to 30 blood samples may be completely processed and assayed within 6 h. As determined with this technique, concentrations of bradykinin in plasma from apparently normal subjects ranged from 2.5 to 5.2 microgram/L (mean 4.2, SD 1.1 microgram/L); these values are consistent with previously reported normal values.

An Electrophysiological Measure of Temporal Resolution in Normal Subjects Using Frequency Modulated Signals

2002 ◽  
Vol 11 (1) ◽  
pp. 42-49
Author(s):  
Devin L. McCaslin ◽  
Lawrence L. Feth ◽  
Gary P. Jacobson ◽  
Pamela J. Mishler
Keyword(s):  
Temporal Resolution ◽  
Mismatch Negativity ◽  
Normal Subjects ◽  
Single Step ◽  
Event Related Potential ◽  
Frequency Range ◽  
Temporal Properties ◽  
Step Duration ◽  
The Mean ◽  
Modulated Signals

This investigation was conducted to determine whether an exogenous event-related potential called the mismatch negativity (MMN) would change systematically in response to frequency-modulated signals with varying temporal properties. Both N1 and P2 waveforms were recorded for 50-ms frequency-modulated signals from normal hearing listeners. The standard stimuli for this investigation were continuous sweep tones with center frequencies of 1000 Hz that traversed a frequency range of 200 Hz in a single step. The rare stimuli were signals that traversed the same frequency range in two, four, six, or eight discrete steps. Results suggest that for the 10 participants, 1) the mean MMN peak-to-peak amplitude and mean area decreased significantly with decreases in step duration, 2) MMN area amplitude was the best indicator of psychophysical performance for the two magnitude measures, and 3) MMN onsets and peak latencies did not show either a significant increase or decrease in latency as step duration decreased.

Enzyme immunoassay of free thyroxin in dried blood samples on filter paper.

1985 ◽  
Vol 31 (5) ◽  
pp. 750-753 ◽  
Author(s):  
N Hata ◽  
K Miyai ◽  
M Ito ◽  
Y Endo ◽  
Y Iijimi ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Filter Paper ◽  
Room Temperature ◽  
Normal Subjects ◽  
Blood Samples ◽  
Double Antibody ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Measurable Range

Abstract We describe a double-antibody enzyme immunoassay for determination of free thyroxin (FT4) in dried blood samples on filter paper, with use of a T4-beta-D-galactosidase complex. The measurable range of FT4 concentration in two 3-mm blood discs, each of which contained about 2.7 microL of blood, was 1.9 to 93 ng/L, as determined by comparison with concentrations of FT4 in known serum standards. FT4 in blood samples dried on filter paper was stable for at least four weeks when kept dry at -20 degrees C, room temperature, or 37 degrees C. The mean coefficients of variation were 7.6% (within assay) and 6.4% (between assays). Results for FT4 by this method correlated well with those for serum determined by radioimmunoassay (r = 0.98). The proposed method can be used to differentiate persons with hyper- and hypothyroidism from normal subjects and those with abnormal concentrations of thyroxin-binding globulin. The procedure seems suited for screening studies.

Rate-nephelometric determination of fibronectin in plasma.

1985 ◽  
Vol 31 (7) ◽  
pp. 1182-1184 ◽  
Author(s):  
W C van Helden ◽  
A Kok-Verspuy ◽  
G A Harff ◽  
G J van Kamp
Keyword(s):  
Human Plasma ◽  
Normal Values ◽  
Cost Effective ◽  
Analytical Recovery ◽  
Turbidimetric Assay ◽  
Good Agreement

Abstract We describe a kinetic immunonephelometric method for the determination of fibronectin in human plasma, used with the Beckman ICS rate nephelometer. The method is rapid and cost-effective. Two commercially available controls stated by the manufacturer to contain 200 and 295 mg/L were found to contain 198 and 290 mg/L, respectively. Mean analytical recovery was 104%. Within-run precision (CV) for normal samples was 3.8%, between-day precision 5.1%. For samples containing subnormal concentrations of fibronectin, these figures were 3.8% and 6.7%, respectively. Results by the method described here agreed and correlated well with those by a commercially available turbidimetric assay. With appropriately diluted samples, the range of measurement is 40 to 1000 mg/L. Normal values for women and men were 286 (SD 84) and 340 (SD 55) mg/L, respectively, in good agreement with values published by others.

Assessment of markers of bone formation under controlled environmental factors and their correlation with serum minerals in adult sheep as a model for orthopaedic research

2008 ◽  
Vol 42 (4) ◽  
pp. 465-472 ◽  
Author(s):  
I R Dias ◽  
C A Viegas ◽  
J T De Azevedo ◽  
E M Costa ◽  
P Lourenço ◽  
...  
Keyword(s):  
Normal Values ◽  
Healing Process ◽  
Average Weight ◽  
Serum Electrolyte ◽  
Blood Samples ◽  
Non Invasive ◽  
Serum Minerals ◽  
The Mean ◽  
Bone Healing Process ◽  
Markers Of Bone Formation

Summary Eighteen healthy skeletally mature (3 years old) ewes, with an average weight of 45 kg, of the Portuguese Churra da Terra Quente breed were used to evaluate the normal values of total and bone-specific isoform of alkaline phosphatase serum activities (ALP and BALP, respectively) and serum osteocalcin (OC) and their correlation with the serum minerals - calcium (Ca), phosphorus (P), magnesium (Mg) and ionized calcium (Ca2+). The sheep were maintained under controlled environmental conditions (constant diurnal photoperiod cycle and identical husbandry and feeding) for six weeks before the collection of the blood samples. The measurement of the total ALP and serum minerals was performed with automated biochemistry analysers using the BioMérieux® kits, the serum electrolyte Ca2+ Diametrics Medical, Inc® specific cassettes and the BALP and OC METRATM kits from QUIDEL® Corporation. The mean ± standard deviation values obtained were: total ALP 90.17 ± 85.72 U/L, BALP 15.0 ± 5.44 U/L, ratio BALP/ total ALP 29.28 ± 24.22, OC 13.02 ± 1.87 ng/mL, Ca 2.57 ± 0.37 mmol/L, P 2.13 ± 0.42 mmol/L, Mg 1.04 ± 0.13 mmol/L, Ca2+ 1.29 ± 0.04 mmol/L. Significant correlations were observed between the total ALP and Ca ( r = 0.5939; P = 0.05) and OC and Ca ( r = 0.5706; P = 0.05). Reference to the serum values of bone turnover parameters in sheep could be of great value in research and could provide complementary non-invasive information on the bone healing process, particularly with regard to obtaining an early prognosis of fracture healing.

Concentrations of total and free dehydroepiandrosterone in plasma and dehydroepiandrosterone in saliva of normal and hirsute women under basal conditions and during administration of dexamethasone/synthetic corticotropin

1990 ◽  
Vol 36 (12) ◽  
pp. 2042-2046 ◽  
Author(s):  
L M Swinkels ◽  
H A Ross ◽  
A G Smals ◽  
T J Benraad
Keyword(s):  
Chromatographic Separation ◽  
Luteal Phase ◽  
Normal Values ◽  
Normal Subjects ◽  
Follicular Phase ◽  
Strongly Correlated ◽  
Dynamic Tests ◽  
Combined Administration ◽  
Before And After ◽  
The Mean

Abstract Using a specific and sensitive radioimmunoassay involving extraction with diethyl ether and chromatographic separation of steroids, we measured concentrations of salivary and plasma dehydroepiandrosterone (DHEA) in 22 women with normal ovulatory cycles (ages 18-45 years). Salivary DHEA values closely correlated with total and free DHEA in plasma. In the follicular phase the mean concentrations of salivary and plasma free DHEA were virtually equal [mean (SD): 0.61 (0.32) and 0.56 (0.34) nmol/L, respectively]. In the luteal phase, salivary DHEA slightly exceeded the plasma free DHEA [0.68 (0.40) vs 0.56 (0.38) nmol/L, P less than 0.01]. Also, during combined dexamethasone/synthetic corticotropin administration in 25 patients with androgenizing disorders and in 10 normal subjects (each in the follicular and luteal phases), the concentration of DHEA in saliva strongly correlated with total and free DHEA in plasma. During these dynamic tests, the mean concentrations of free DHEA in plasma and salivary DHEA in the hirsute women were significantly higher than the mean concentrations in the control women at all times before and after corticotropin infusion (P less than 0.05- less than 0.0001). In contrast, plasma total DHEA in patients exceeded nonhirsute values only at 15 min after corticotropin administration. In six of 25 patients total DHEA during combined administration of dexamethasone/synthetic corticotropin exceeded normal values by at least 2 SD. The response of salivary and free DHEA to synthetic corticotropin in this subgroup was also excessive.

A radioimmunoassay for bone Gla protein (BGP) in human plasma

1987 ◽  
Vol 114 (3) ◽  
pp. 410-416 ◽  
Author(s):  
Julia S. Johansen ◽  
J. E. Mølholm Hansen ◽  
Claus Christiansen
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Human Plasma ◽  
Biochemical Marker ◽  
Normal Subjects ◽  
Bone Gla Protein ◽  
Low Concentrations ◽  
Metabolic Bone ◽  
The Mean ◽  
Bone Physiology

Abstract. To study the value of bone Gla protein (BGP) as a biochemical marker of normal bone physiology and metabolic bone disorders, we have developed a radioimmunoassay (RIA) for the detection of BGP in human plasma. Antibodies were generated in rabbits immunized with purified calf BGP conjugated to thyroglobulin. Human plasma BGP reacted identically with the calf BGP standard, thus demonstrating the suitability of the assay to measure plasma BGP levels in man. The RIA is sensitive, accurate, and technically simple. Plasma BGP levels were determined in normal subjects (N = 35) and in patients with hypothyroidism (N = 10), hyperthyroidism (N = 22) and chronic renal failure (N = 35). The mean (± 1 sem) concentration of plasma BGP in normal subjects was 1.27 ± 0.07 nmol/l. Plasma BGP was significantly increased in patients with hyperthyroidism, 4.04 ± 0.78 nmol/l (P < 0.001) and chronic renal failure, 10.17 ± 2.47 nmol/l (P < 0.001). Low concentrations were found in patients with hypothyroidism, 0.74 ± 0.11 nmol/l (P <0.01). Our studies indicate that plasma BGP provides a useful technique in the diagnosis of patients with bone disease.

An investigation of LH pulsatility in burned men by bioassay and radioimmunoassay

1992 ◽  
Vol 126 (5) ◽  
pp. 404-409 ◽  
Author(s):  
CG Semple ◽  
R Mitchell ◽  
S Hollis ◽  
WR Robertson
Keyword(s):  
Biological Activity ◽  
Serum Testosterone ◽  
Normal Subjects ◽  
Published Data ◽  
Blood Samples ◽  
Testosterone Concentration ◽  
Lh Pulsatility ◽  
Pulse Peak ◽  
The Mean ◽  
Normal Men

LH pulsatility studies were performed in six burned patients by removing blood samples at 10 min intervals over a 6 h period. All samples were assayed for LH by bioassay (B-LH), LH by radioimmunoassay (I-LH) and testosterone. Mean serum testosterone concentrations of the burned patients were low (6.7±1.6 nmol/l). I-LH levels were lower than B-LH in all samples. Frequency of bioactive or immunoreactive pulses as well as mean B-LH and I-LH concentrations were similar to previously published data from normal men examined in the same laboratory. The mean biological activity of LH (expressed as the ratio of B-LH to I-LH, the B:I ratio) was lower in burned subjects (1.9±0.1) than previously reported in normal men. The B:I ratios of burned men were lower (p <0.01) at pulse peaks than at nadirs (1.8±0.1 vs 2.0±0.1) and an increase in serum testosterone concentration did not follow an LH peak. Serum testosterone concentrations did not cross-correlate with B-LH or I-LH. This contrasts with the findings in normal subjects where the B:I ratios have been found to be higher at pulse peaks than at nadirs and an increase in serum testosterone concentration follows a pulse peak and serum testosterone cross-correlates with B-LH and I-LH. LH secreted in a pulse peak in normal men may contain a particularly biologically potent form of the molecule but this may not be the case in burned men.

Urine contains an inhibitor for turbidimetric determinations of protein.

1982 ◽  
Vol 28 (11) ◽  
pp. 2294-2296
Author(s):  
J Nakamura ◽  
M Yakata
Keyword(s):  
Molecular Mass ◽  
Gamma Globulin ◽  
Gel Filtration ◽  
Relative Molecular Mass ◽  
Sulfosalicylic Acid ◽  
Turbidimetric Method ◽  
Analytical Recovery ◽  
Dye Binding ◽  
Turbidimetric Assay ◽  
Contrast Measurement

Abstract Our examination of urine components separated by gel filtration revealed the presence of an inhibitor that decreases the analytical recovery of protein in a turbidimetric assay involving sulfosalicylic acid as reagent (Proc. Soc. Exp. Biol. Med. 92: 748, 1956). The apparent relative molecular mass of this inhibitor was in the range 160 000-240 000. A study with purified proteins showed a similar inhibition by gamma-globulin, glycoprotein, and beta-lipoprotein in the assay of albumin by the same turbidimetric method. In contrast, measurement of protein by a dye binding method was not affected by these materials. The low values for apparent urinary protein given by the turbidimetric method as compared with those by the dye-binding method are at least partly ascribable to the inhibitor.

Dilution of plasma with Tris buffer increases measured catecholamines in plasma.

1987 ◽  
Vol 33 (3) ◽  
pp. 408-411 ◽  
Author(s):  
J L Cuche ◽  
F Selz ◽  
G Ruget ◽  
M Gentil ◽  
C Gaudin
Keyword(s):  
Molecular Mass ◽  
Human Plasma ◽  
Tris Buffer ◽  
Plasma Samples ◽  
Internal Standards ◽  
Analytical Recovery ◽  
Proportional Decrease ◽  
Radioenzymatic Assays ◽  
Mass Component ◽  
Catecholamine Concentration

Abstract We investigated the effects of dilution of plasma samples on the measured concentrations of catecholamines. Diluting samples of human plasma 10-, 50-, and 100-fold with Tris buffer (100 mol/L, pH 8.6) improved analytical recovery of internal standards, suggesting that it decreases the commonly observed inhibition of methylation in radioenzymatic assays of catecholamines in plasma. However, the dilution is not associated with a proportional decrease in counted radioactivity. This extra amount of radioactivity, which is unlikely to be nonspecific in origin, accounts for a significant increase in the calculated catecholamine concentration. Tentatively, we suggest that Tris buffer releases both catecholamines and conjugated catecholamines bound to some unidentified low-molecular-mass component of plasma.

Sign in / Sign up

Export Citation Format

Share Document