Immunoassay of low concentrations of albumin in urine by latex particle counting.

1988 ◽  
Vol 34 (2) ◽  
pp. 416-418 ◽  
Author(s):  
C L Cambiaso ◽  
D Collet-Cassart ◽  
M Lievens
Keyword(s):  
Detection Limit ◽  
Dose Response ◽  
Response Curve ◽  
Latex Particle ◽  
Urinary Albumin ◽  
Diagnostic Systems ◽  
Particle Counting ◽  
Low Concentrations ◽  
The Impact

Abstract We describe here a nonisotopic immunoassay, based on particle-counting technology, for the determination of urinary albumin. The assay takes only 35 min and has been fully automated on the IMPACT (Acade Diagnostic Systems, Brussels, Belgium) machine. The system measures albumin within a linear range between 6.25 and 50 mg/L and has a detection limit of 0.4 mg/L. Analytical recoveries at three concentrations ranged between 96% and 102%. Within-run precision ranged from 1.6% to 9.5%. The method was compared with a commercial nephelometric immunoassay system and a correlation coefficient of 0.996 was found for 216 urine samples. No antigen excess affects the shape of the curve in our system, whereas in nephelometry a 3 g/L solution of albumin starts to decrease the dose-response curve.

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.

Copper inhibits pressor responses to noradrenaline but not potassium. Interactions with prostaglandins E1, E2, and I2 and penicillamine

1979 ◽  
Vol 57 (1) ◽  
pp. 35-40 ◽  
Author(s):  
S. C. Cunnane ◽  
H. Zinner ◽  
D. F. Horrobin ◽  
M. S. Manku ◽  
R. O. Morgan ◽  
...  
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Wilson’S Disease ◽  
Wilson's Disease ◽  
Biological Action ◽  
Dose Response Curve ◽  
Low Concentrations ◽  
Pressor Responses ◽  
The Right ◽  
Copper Effect

Low concentrations of copper inhibited responses to norepinephrine and angiotensin (IC50 3 × 10−6 M) but not to potassium in rat mesenteric vascular preparations perfused either with buffer or indomethacin and prostaglandin (PGE2). The dose–response curve was not shifted by indomethacin, imidazole, or PGE2 but was moved to the right by 2.8 × 10−11 M PGE1 and to the left by 2.8 × 10−7 M PGE1. These effects of copper are similar to the effects of PGI2 in the preparation. Copper moved the PGI2 dose–response curve against noradrenaline in parallel to the left, suggesting that the two were interacting at some point. Penicillamine, which may stimulate PGE1 synthesis, had PGE1-like interactions with the copper effect, suggesting that its value in Wilson's disease may be partly due to antagonism of the biological action of copper as well as to its copper-chelating properties.

Two-monoclonal-antibody "sandwich"-type assay of human lutropin, with no cross reaction with choriogonadotropin.

1987 ◽  
Vol 33 (9) ◽  
pp. 1603-1607 ◽  
Author(s):  
W D Odell ◽  
J Griffin
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Detection Limit ◽  
Dose Response ◽  
Response Curve ◽  
Cross Reaction ◽  
Dose Response Curve ◽  
Low Doses ◽  
Human Choriogonadotropin ◽  
Sandwich Type

Abstract We have developed a sensitive, specific, noncompetitive sandwich-type assay for human lutropin (hLH). Two monoclonal antibodies are used, and there is no cross reaction with human choriogonadotropin (hCG) or human follitropin (hFSH), and little or none with human thyrotropin (hTSH). There also is no reaction with the free beta chains of hLH and hCG. The detection limit is less than 0.5 int. units of hLH per liter of serum, and the dose-response curve is linear between 0 and 10 int. units/L. The intra-assay CV averaged 5.4% at low doses of hLH; the interassay CV averaged 12.5%.

Nanomolar ouabain augments caffeine-evoked contractions in rat arteries

1993 ◽  
Vol 265 (5) ◽  
pp. C1443-C1448 ◽  
Author(s):  
D. N. Weiss ◽  
D. J. Podberesky ◽  
J. Heidrich ◽  
M. P. Blaustein
Keyword(s):  
Dose Response ◽  
Mesenteric Artery ◽  
Response Curve ◽  
Dose Response Curve ◽  
Response Curves ◽  
Low Concentrations ◽  
Vascular Responsiveness ◽  
Subunit Isoforms ◽  
Evoked Contractions ◽  
Small Mesenteric Artery

Chronic parenteral administration of ouabain to normal rats raises plasma ouabain concentrations to low nanomolar levels and induces hypertension [C. M. Yuan, P. Manunta, J. M. Hamlyn, S. W. Chen, E. Bohen, J. Yeun, F. J. Haddy, and M. B. Pamnani. Hypertension 22: 178-187, 1993 and see also M. P. Blaustein. Am. J. Physiol. 264 (Cell Physiol. 33): C1367-C1387, 1993]. To determine whether rat arteries are sensitive to these low ouabain levels, we tested the effects of various ouabain concentrations on caffeine-evoked contractions (CEC) in rat aortic and small mesenteric artery rings. CEC amplitude was used as a measure of the sarcoplasmic reticulum (SR) Ca2+ content. Ouabain increased CEC in aortic as well as mesenteric artery rings, but the effects in the aorta were difficult to quantitate because the CEC were often oscillatory. Mesenteric artery, under control conditions and after sensitization with 10-30 nM phenylephrine (PE), exhibited biphasic ouabain dose-CEC response curves. Low concentrations of ouabain (0.1-10 nM) caused small significant increases in CEC, but a further effect was observed only with > or = 10 microM ouabain. PE shifted the ouabain dose-response curve toward lower ouabain concentrations; conversely, ouabain shifted the PE dose-response curve toward lower PE concentrations. It appears that nanomolar concentrations of ouabain can influence vascular responsiveness to vasoconstrictors. We conclude that rat vascular smooth muscle contains both high- and low-affinity ouabain receptors, possibly corresponding to Na+ pumps with alpha 3- and alpha 1-subunit isoforms, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of Honey Authenticity by Capillary Gas Chromatography

1995 ◽  
Vol 78 (5) ◽  
pp. 1210-1218 ◽  
Author(s):  
Nicholas H Low ◽  
Wendy South
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
North America ◽  
Capillary Gas Chromatography ◽  
Invert Sugar ◽  
Trimethylsilyl Ethers ◽  
Low Concentrations ◽  
Sugar Addition

Abstract Methodology using capillary gas chromatography was developed to determine addition of invert syrups (beet or cane) to honey. Fingerprint oligosaccharides, which were either not detectable or present in low concentrations in pure honey, were found in these inexpensive sweeteners. Oligosaccharides were analyzed as their trimethylsilyl ethers. Sixty-eight pure honey samples produced in continental North America, Hawaii, China, and Australia were analyzed. The detection limit for invert sugar addition was 5%.

Reversible and irreversible interactions of DIDS with the human electrogenic Na/HCO3 cotransporter NBCe1-A: role of lysines in the KKMIK motif of TM5

2007 ◽  
Vol 292 (5) ◽  
pp. C1787-C1798 ◽  
Author(s):  
Jing Lu ◽  
Walter F. Boron
Keyword(s):  
Voltage Clamp ◽  
Dose Response ◽  
Response Curve ◽  
Xenopus Oocytes ◽  
Transmembrane Segment ◽  
Initial Value ◽  
Irreversible Inhibition ◽  
Electrode Voltage

Others have shown that H2DIDS reversibly and covalently binds to the first lysine (K) in the SKLIK motif at the extracellular end of transmembrane segment 5 of the Cl-HCO3 exchanger AE1. Here we mutated K558, K559, and/or K562 in the homologous KKMIK motif of human NBCe1-A. We expressed constructs in Xenopus oocytes, and used a two-electrode voltage clamp to test the sensitivity of the NBC current (−160 to +20 mV) to DIDS. A 30-s DIDS exposure decreased the current at 0 mV, and a subsequent albumin wash returned the current to the initial value (less any irreversible DIDS inhibition), permitting the determination of a complete dose-response curve on a single oocyte. For all constructs, the reversible DIDS inhibition of the NBC current decreased at more negative voltages. The apparent inhibitory constant for reversible DIDS binding increased in the sequence RRMIR < KKMIK ( wt, ∼40 μM) < NKMIK ≅ NKMIN ≅ KKMIN < KNMIN ≅ KNMIK < NNMIK < NNMIN (∼400 μM) < DDMID < EEMIE (∼800 μM). Thus the second K is the most important for reversible DIDS blockade. Nevertheless, these mutations had relatively little effect on slope conductance in the absence of DIDS. For KKMIK, RRMIR, NKMIK, KKMIN, KNMIK, and NNMIN, the rates of irreversible inhibition by DIDS roughly parallel the apparent affinities for reversible DIDS binding. The rate was extremely low for DDMID. The fitted maximal inhibitions were 80–91% for the first five constructs, and 66% for NNMIN. Thus DIDS probably reversibly binds before irreversibly reacting with NBCe1-A. Finally, tenidap blocks not only KKMIK, but also NNMIN and EEMIE.

Evaluation of cinnamamide as an avian repellent: Determination of a dose-response curve

1995 ◽  
Vol 44 (4) ◽  
pp. 335-340 ◽  
Author(s):  
Richard W. Watkins ◽  
Elaine L. Gill ◽  
Julie D. Bishop
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve

scholarly journals Nanoemulsion Improves Antinociceptive Activity of HP1, a Benzopyran from Hypericum polyanthemum

2017 ◽  
Vol 4 (03) ◽  
pp. e82-e88 ◽  
Author(s):  
Gabriela Meirelles ◽  
Henrique Bridi ◽  
Eveline Stolz ◽  
Helder Teixeira ◽  
Gilsane von Poser ◽  
...  
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Antinociceptive Effect ◽  
Free Form ◽  
Absorption Enhancement ◽  
High Solubility ◽  
Hot Plate ◽  
Hot Plate Test ◽  
Plate Test ◽  
The Impact

AbstractThe impact of nanoemulsification on the antinociceptive effect of benzopyran HP1 in a mice hot plate test was investigated. For comparison, the same experiments were performed with HP1-free form. The durability of the antinociceptive effect was analyzed at 60, 120 and 180 min. The results revealed that HP1 was successfully incorporated into a nanoemulsion system, given its high solubility in the oil phase. Regarding the pharmacological effect, HP1 (15, 30, 45, and 60 mg/kg, p.o.), both forms, displayed the pattern of a bell-shaped dose-response curve. HP1-loaded nanoemulsion displayed the maximal antinociceptive effect at a lower dose than the HP1-free form. The highest effect of the free compound was observed at 45 mg/kg, while the HP1-loaded nanoemulsion displayed the same effect at 30 mg/kg. These results suggest that the observed effect might be attributable to an increase in solubility and, thus, the enhancement of compound absorption. Regarding the durability of the antinociceptive effect, the outcomes demonstrated that the HP1-free form lost its antinociceptive effect at 120 min, while the HP1-loaded nanoemulsion kept its effect until 180 min. These findings corroborate literature data, where studies have demonstrated absorption enhancement when a compound was loaded in a nanoemulsion system.

Advances in and Limitations of Up-and-down Methodology

2007 ◽  
Vol 107 (1) ◽  
pp. 144-152 ◽  
Author(s):  
Nathan L. Pace ◽  
Mario P. Stylianou ◽  
David C. Warltier
Keyword(s):  
Statistical Methods ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Binary Response ◽  
Target Dose ◽  
Anesthesia Research ◽  
Tolerance Distribution ◽  
Probability Of Response

Abstract Sequential design methods for binary response variables exist for determination of the concentration or dose associated with the 50% point along the dose–response curve; the up-and-down method of Dixon and Mood is now commonly used in anesthesia research. There have been important developments in statistical methods that (1) allow the design of experiments for the measurement of the response at any point (quantile) along the dose–response curve, (2) demonstrate the risk of certain statistical methods commonly used in literature reports, (3) allow the estimation of the concentration or dose—the target dose—associated with the chosen quantile without the assumption of the symmetry of the tolerance distribution, and (4) set bounds on the probability of response at this target dose. This article details these developments, briefly surveys current use of the up-and-down method in anesthesia research, reanalyzes published reports using the up-and-down method for the study of the epidural relief of pain during labor, and discusses appropriate inferences from up-and-down method studies.

scholarly journals STUDIES ON THE PATHOGENESIS OF FEVER

1962 ◽  
Vol 115 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Hans Klaus Kaiser ◽  
W. Barry Wood
Keyword(s):  
Dose Response ◽  
Normal Saline ◽  
Response Curve ◽  
Buffy Coat ◽  
Polymorphonuclear Leucocytes ◽  
Endogenous Pyrogen ◽  
Rabbit Blood ◽  
Metabolic Reactions ◽  
Cell Fragments

Determination of the dose-response curve for rabbit leucocytic pyrogen reveals a hyperthermic "ceiling" at which there is a marked insensitivity to dosage. This finding has important implications in relation to the quantitative assay of leucocytic pyrogen. Polymorphonuclear leucocytes separated from normal rabbit blood possess the capacity to produce less than 5 per cent of the pyrogen generated by the same number of rabbit granulocytes collected from acute peritoneal exudates. Blood granulocytes, separated in the cold from the buffy coat, contain no detectable preformed pyrogen. The amount of preformed pyrogen within exudate granulocytes represents but a small fraction of the pyrogen which the cells are capable of generating when incubated in normal saline at 37°C. It is suggested that the active pyrogen is formed from an inactive precursor within the cells. Under the conditions tested, cell fragments of rabbit granulocytes fail to produce endogenous pyrogen. The fact that the production of pyrogen is blocked at 4°C is in keeping with the hypothesis that it involves metabolic reactions within the cell.

Sign in / Sign up

Export Citation Format

Share Document