Radioimmunoassay for immunologlobulin G in serum and urine.

1979 ◽  
Vol 25 (12) ◽  
pp. 2015-2019 ◽  
Author(s):  
J Woo ◽  
M Floyd ◽  
M A Longley ◽  
D C Cannon
Keyword(s):  
Dose Response ◽  
Allograft Rejection ◽  
Response Curve ◽  
Renal Allograft ◽  
Response Curves ◽  
Assay Sensitivity ◽  
Renal Allografts ◽  
Serum Igg ◽  
Normal Individuals ◽  
Serum And Urine

Abstract We describe a radioimmunoassay for immunoglobulin G (IgG) in serum and urine. Aliquots of diluted samples and 125I-labeled IgG were incubated in antibody-coated tubes at 37 degrees C for 24 h, the supernates were decanted, and the radioactivity in tubes containing the bound fraction was counted. The dose-response curve in the range of 0.4--500 mg/L of urine or 640--40 000 mg/L of serum was linear on logit-log transformation and iterative weighted regression. Assay sensitivity was 10 ng of IgG. Validation studies included testing for precision, accuracy, antibody specificity, and parallelism of the dose-response curves for standard and unknown. In a study of 14 apparently normal individuals, serum IgG = 4.0-10.9 gL, urine IgG = 1.1-4.8 mg/24 h, and IgG clearance = 0.2 X 10(-4) to 4.8 X 10(-4) mL/min. In 20 patients with renal allografts, serum IgG = 15.8-66 g/L, urine IgG - 9.6-626 mg/24 h, and IgG clearance = 9 X 10(-4) to 1.99 X 10(-1) mL/min. IgG values correlated well with severity of renal allograft rejection.

beta 2-Microglobulin clearance as measured by radioimmunoassay.

1980 ◽  
Vol 26 (8) ◽  
pp. 1193-1197 ◽  
Author(s):  
J Woo ◽  
M Floyd ◽  
M A Longley ◽  
D C Cannon
Keyword(s):  
Dose Response ◽  
Renal Allograft ◽  
Rabbit Antiserum ◽  
Response Curves ◽  
Assay Sensitivity ◽  
Antibody Technique ◽  
Normal Individuals ◽  
Beta 2 ◽  
Beta 2 Microglobulin ◽  
Serum And Urine

Abstract We describe a radioimmunoassay for beta 2-microglobulin (beta 2 mu) in serum and urine. We incubated aliquots of diluted samples at room temperature for 1 h with 125I-labeled beta 2 mu and a rabbit antiserum monospecific for human beta 2 mu, and separated the phases by the double-antibody technique. The logit-log transformed dose-response curve was linear in the range 2 to 64 ng, equivalent to 0.5 to 16 mg/L of serum and 0.5 to 320 mg/L of urine. Assay sensitivity was 2.4 ng of beta 2 mu. Validation studies included tests of precision, accuracy, antibody specificity, and parallelism of the dose-response curves for standard and unknown. In a study of 25 normal individuals, serum and urine beta 2 mu ranged from 1.1 to 2.3 mg/L and 40 to 360 micrograms/24 h; the clearance of beta 2 mu was 8 to 130 microL/min. In 21 renal allograft recipients tested one to five weeks after transplantation, serum and urine beta 2 mu ranged from 3.9 to 15.6 mg/L and 7.2 to 611 mg/24 h; beta 2 mu clearance was 0.60 to 33.3 mL/min. Values for both serum and urine correlated well with severity of allograft rejection.

Factor VII Clotting Assay: Influence of Different Thromboplastins and Factor VII-Deficient Plasmas

1991 ◽  
Vol 65 (02) ◽  
pp. 160-164 ◽  
Author(s):  
Marina Poggio ◽  
Armando Tripodi ◽  
Guglielmo Mariani ◽  
Pier Mannuccio Mannucci ◽  
Keyword(s):  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Dose Response ◽  
Response Curve ◽  
Ischemic Heart ◽  
Factor Vii ◽  
Response Curves ◽  
Assay Sensitivity ◽  
Clinical Laboratories ◽  
Coagulant Activity

SummaryBeing a putative predictor of ischemic heart disease, the measurement of factor VII (FVTI) coagulant activity will be presumably requested to clinical laboratories with increasing frequency. To assess the influence on FVII assays of different thromboplastins and FVII-deficient plasmas we compared performances of all possible combinations of 5 thromboplastins and 6 deficient plasmas. The reproducibility of the clotting times of the dose-response curves for human and rabbit thromboplastins were acceptable (CV lower than 7%), whereas bovine thromboplastin had a higher CV. Reproducibility was very similar for all deficient plasmas when they were used in combination with a given thromboplastin. Responsiveness of the dose-response curve did not depend on the deficient plasma but rather on the thromboplastin: one rabbit thromboplastin was the least responsive, the bovine thromboplastin the most responsive, the human and the remaining two rabbit thromboplastins had intermediate responsiveness. Assay sensitivity to cold-activated FVII varied according to the thromboplastin: the bovine thromboplastin was the most sensitive, the human thromboplastin the least sensitive, of the three rabbit thromboplastins two were relatively sensitive, one was almost insensitive. In conclusion, our results indicate that thromboplastin rather than deficient plasma is the crucial factor in the standardization of FVII assay.

OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1967 ◽  
Vol 56 (4) ◽  
pp. 619-625 ◽  
Author(s):  
Hans Jacob Koed ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Origin ◽  
Response Curves ◽  
Significant Difference ◽  
The Mean ◽  
Different Levels

ABSTRACT Comparison of the dose-response curves for LH of ovine origin (NIH-LH-S8) and of human origin (IRP-HMG-2) using the OAAD test showed a small, though statistically significant difference, the dose-response curve for LH of human origin being a little flatter. Two standard curves for ovine LH obtained with 14 months' interval, were parallel but at different levels of ovarian ascorbic acid. When the mean ascorbic acid depletions were calculated as percentages of the control levels, the two curves for NIH-LH-S8 were identical. The use of standards of human origin in the OAAD test for LH activity of human preparations is recommended.

Method for testing antiserum titer and avidity in nephelometric systems.

1981 ◽  
Vol 27 (11) ◽  
pp. 1838-1844 ◽  
Author(s):  
G A Hudson ◽  
R F Ritchie ◽  
J E Haddow
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Direct Evidence ◽  
Reaction Rates ◽  
Dose Response Curve ◽  
Antigen Concentration ◽  
Response Curves ◽  
Binding Strength ◽  
Antiserum Dilution ◽  
Antiserum Titer

Abstract Antiserum performance in a nephelometric system can be characterized by parameters derived from measuring reaction rates. The characterization process is derived from a series of dose-response curves (elicited nephelometric response vs antigen concentration) generated from various dilutions of the antiserum being tested. Antiserum titer can then be calculated by plotting the antigen concentration found at one-half the maximum nephelometric response (Hmax) of each dose-response curve (C50) vs the corresponding antiserum dilution. Antiserum avidity can be calculated by plotting Hmax against its corresponding antiserum concentration. After general expressions are determined for C50 and Hmax vs antiserum concentration, a single dose-response curve suffices for characterizing antisera with respect to titer and avidity. Direct evidence is provided for the validity of C50 and Hmax as measures of titer and avidity by correlating these parameters with antiserum binding strength and with the number of antibodies eluted from immobilized antigen. This method can be applied to evaluate and compare different antiserum lots having the same specificity, to identify reagent inadequacies by comparing antisera of different specificity, and to predict the optimal antiserum dilution to use in performing an assay.

Oxytocin as an antidiuretic hormone. II. Role of V2 vasopressin receptor

1995 ◽  
Vol 269 (1) ◽  
pp. F78-F85 ◽  
Author(s):  
C. L. Chou ◽  
S. R. DiGiovanni ◽  
A. Luther ◽  
S. J. Lolait ◽  
M. A. Knepper
Keyword(s):  
Dose Response ◽  
Water Permeability ◽  
Response Curve ◽  
Collecting Duct ◽  
Oxytocin Receptor ◽  
Dose Response Curve ◽  
Vasopressin Receptor ◽  
Response Curves ◽  
V2 Receptor ◽  
V2 Vasopressin Receptor

We conducted this study to determine what receptor mediates the effect of oxytocin to increase osmotic water permeability (Pf) in the rat inner medullary collecting duct (IMCD). Reverse transcription-polymerase chain reaction (RT-PCR) experiments demonstrated that mRNA for both the oxytocin receptor and the V2 receptor is present in the rat terminal IMCD. In isolated perfused IMCD segments, we found that the V2 vasopressin receptor antagonist [d(CH2)5(1),D-Ile2,Ile4,Arg8]vasopressin, but not oxytocin receptor antagonists, blocked the hydrosmotic response to 200 pM oxytocin. The selective oxytocin receptor agonist [Thr4,Gly7]oxytocin did not increase water permeability. Oxytocin also increased urea permeability in IMCD segments. Studies in IMCD suspensions showed that oxytocin increases adenosine 3',5'-cyclic monophosphate production in a dose-dependent fashion with a half-maximal (EC50) response at 5.2 nM. The dose-response curves were virtually identical for IMCD suspensions from Sprague-Dawley rats and Brattleboro rats. The oxytocin dose-response curve was displaced to the right of the vasopressin dose-response curve (EC50, 0.44 nM). From these results, we conclude that the V2 receptor mediates the hydrosmotic action of oxytocin in rat IMCD.

A Study of the Acid Dose-Response Curve to Small Doses of Pentagastrin in Duodenal Ulcer Patients

1972 ◽  
Vol 43 (2) ◽  
pp. 181-191
Author(s):  
J. B. Elder ◽  
G. Gillespie ◽  
E. H. G. Campbell ◽  
I. E. Gillespie ◽  
G. P. Crean ◽  
...  
Keyword(s):  
Duodenal Ulcer ◽  
Body Weight ◽  
Dose Response ◽  
Response Curve ◽  
Acid Output ◽  
Twilight Zone ◽  
Response Curves ◽  
Small Doses ◽  
Threshold Doses ◽  
Body Weight Dose

1. The acid secretory responses to a range of small doses of pentagastrin in 0·15 m-NaCl have been studied in thirty-one preoperative duodenal ulcer subjects. Acid output increased significantly above basal values when a dose of 0·064 μg h−1 kg−1 was given. 2. Control observations in sixteen duodenal ulcer patients using the saline solvent alone at identical rates of infusion showed no significant increase in acid output. 3. From the dose-response curves sub-threshold and threshold doses of pentapeptide are suggested for duodenal ulcer patients before truncal vagotomy. 4. Considerable variation in acid response was noted between patients given the same body-weight dose of pentapeptide. The results suggest that a ‘twilight zone’ of stimulation exists between the dose of pentagastrin by which few patients are stimulated and the dose by which the majority are stimulated. This may reflect some variation in the sensitivity to stimulation by pentagastrin from one patient to another.

Implications of hormesis on the bioassay and hazard assessment of chemical carcinogens

1998 ◽  
Vol 17 (5) ◽  
pp. 254-258 ◽  
Author(s):  
Justin G Teeguarden ◽  
Yvonne P Dragan ◽  
Henry C Pitot
Keyword(s):  
Hazard Assessment ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Low Doses ◽  
Response Curves ◽  
Large Numbers ◽  
Carcinogenic Agents ◽  
Assessment Guidelines ◽  
Study Designs

Hormesis has been defined as a dose-response relationship which depicts improvement in some endpoint (increased metabolic rates, reduction in tumor incidence, etc.) at low doses of a toxic compound followed by a decline in the endpoint at higher doses. The existence of hormetic responses to carcinogenic agents has several implications for the bioassay and hazard assessment of carcinogens. To be capable of detecting and statistically testing for hormetic or other nonlinear dose-response functions, current study designs must be modified to include lower doses and sufficiently large numbers of animals. In addition, improved statistical methods for testing nonlinear dose-response relationships will have to be developed. Research integrating physiologically-based pharmacokinetic model descriptions of target dose with mechanistic data holds the greatest promise for improving the description of the dose-response curve at low doses. The 1996 Proposed Carcinogen Risk Assessment Guidelines encourage the use of mechanistic data to improve the descriptions of the dose-response curve at low doses, but do not distinguish between the types of nonlinear dose-response curves. Should this refined approach lead to substantial support for hormesis in carcinogenic processes, future guidelines will need to provide guidance on establishing safe doses and communicating the results to the public.

The Influence of Sodium Intake on the Pressor Response to Angiotensin II in the Unanaesthetized Rat

1976 ◽  
Vol 50 (4) ◽  
pp. 285-291
Author(s):  
Barbara L. Slack ◽  
J. M. Ledingham
Keyword(s):  
Angiotensin Ii ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Response Curves ◽  
High Sodium ◽  
Sodium Diet ◽  
Low Sodium Diet ◽  
Low Sodium ◽  
High Sodium Diet

1. Dose—response curves for the pressor activity of angiotensin II have been determined in unanaesthetized rats receiving diets containing 2·5% (w/w) or 0·007% (w/w) sodium; the different diets were administered in various sequences. 2. In comparison with those from rats receiving a low sodium diet, the dose—response curves were displaced to the left on the high sodium diet, indicating a greater response to angiotensin, and this displacement persisted for a period of approximately 7 days after the diet was changed from high to low sodium. The dose—response curve subsequently shifted to the right when the low sodium diet was maintained for longer. 3. There was a negative correlation between the slope of the dose—response curve and the basal blood pressure in all groups; the correlation was significant in three out of the five different treatment groups. 4. Basal blood pressures were significantly raised in rats on the high sodium diet for 7 days. 5. A number of possible mechanisms have been considered to explain both the parallel shift of the dose—response curve and alteration in its slope. It is concluded that the observed findings are compatible with an action of sodium-loading on the sensitivity of the smooth muscle cell to angiotensin, on the resting of the renin—angiotensin system, on the rate of in-activation of angiotensin and on a change in initial length of the muscle fibre.

The sensitivity of prolactin secretion to dopamine changes during pregnancy in mice

1986 ◽  
Vol 111 (4) ◽  
pp. 567-571
Author(s):  
Stacey R. Swartz ◽  
Linda Ogren ◽  
Frank Talamantes
Keyword(s):  
Dose Response ◽  
Anterior Pituitary ◽  
Response Curve ◽  
Prolactin Secretion ◽  
Dose Response Curve ◽  
Serum Prolactin ◽  
Response Curves ◽  
Dopamine Concentration ◽  
Pituitary Glands ◽  
Low Levels

Abstract. Pituitary responsiveness to dopamine was investigated on several days of pregnancy in the mouse. Sera and anterior pituitary glands were obtained at 09.00 and 18.00 h on day 5 of pregnancy and at 09.00 h on days 12 and 18, and the pituitaries were incubated for 5 h in several concentrations of dopamine (0, 5 × 10−10—5 × 10−7 m). Serum prolactin (Prl) concentration was the highest on day 5 (18.00 h sample), followed by day 18 (09.00 h), day 5 (09.00 h) and day 12 (09.00 h). Pituitary responsiveness to dopamine was assessed on each day of pregnancy by determining the slopes of dose-response curves in which the Prl concentration of the medium was plotted as a function of dopamine concentration. The slope of the dose-response curve for pituitaries from day 12 or pregnancy was significantly steeper than the slopes of the curves for pituitaries from days 5 and 18, which did not differ from each other. These data suggest that the Prl secretion mechanism is more sensitive to inhibition by dopamine on day 12 of pregnancy, when serum Prl concentration is very low, than on days 5 or 18, when serum Prl concentrations are higher. One of the mechanisms by which circulating Prl concentrations are reduced to very low levels during midpregnancy in the mouse may be increased pituitary sensitivity to dopamine.

scholarly journals Control of glyphosate resistant hairy fleabane (Conyza bonariensis) with dicamba and 2,4-D

2012 ◽  
Vol 30 (2) ◽  
pp. 401-406 ◽  
Author(s):  
D.J. Soares ◽  
W.S. Oliveira ◽  
R.F. López-Ovejero ◽  
P.J Christoffoleti
Keyword(s):  
Experimental Design ◽  
Dose Response ◽  
Growth Regulator ◽  
Response Curve ◽  
Poor Control ◽  
Response Curves ◽  
Conyza Bonariensis ◽  
Randomized Experimental Design ◽  
Low Sensitivity ◽  
Hairy Fleabane

Auxyn type herbicides such as dicamba and 2,4-D are alternative herbicides that can be used to control glyphosate-resistant hairy fleabane. With the forthcoming possibility of releasing dicamba-resistant and 2,4-D-resistant crops, use of these growth regulator herbicides will likely be an alternative that can be applied to the control of glyphosate resistant hairy fleabane (Conyza bonariensis). The objective of this research was to model the efficacy, through dose-response curves, of glyphosate, 2,4-D, isolated dicamba and glyphosatedicamba combinations to control a brazilian hairy fleabane population resistant to glyphosate. The greenhouse dose-response studies were conducted as a completely randomized experimental design, and the rates used for dose response curve construction were 0, 120, 240, 480, 720 and 960 g a.i. ha-1 for 2,4-D, dicamba and the dicamba combination, with glyphosate at 540 g a.e. ha-1. The rates for glyphosate alone were 0, 180, 360, 540, 720 and 960 g a.e. ha-1. Herbicides were applied when the plants were in a vegetative stage with 10 to 12 leaves and height between 12 and 15 cm. Hairy fleabane had low sensitivity to glyphosate, with poor control even at the 960 g a.e. ha-1 rate. Dicamba and 2,4-D were effective in controlling the studied hairy fleabane. Hairy fleabane responds differently to 2,4-D and dicamba. The combination of glyphosate and dicamba was not antagonistic to hairy fleabane control, and glyphosate may cause an additive effect on the control, despite the population resistance.

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