scholarly journals Inactivation of Gonadotrophins IV. the Effect of Periodate Ions and "Blood-Group Enzym,E" on the Biological Activity of Chorionic Gonadotrophin

1953 ◽  
Vol 6 (2) ◽  
pp. 300 ◽  
Author(s):  
WK Whitten
Keyword(s):  
Influenza Virus ◽  
Biological Activity ◽  
Blood Group ◽  
Dose Response ◽  
Response Curve ◽  
Chorionic Gonadotrophin ◽  
Dose Response Curve ◽  
Low Doses ◽  
Accurate Comparison

Treatment of chorionic. gonadotrophin with periodate ions mo<;lified the ,hormone so that it was no longer :inactivated by influenza virus. T1).e. dose response curve of the treated hormone was less steep than for untreated, which precluded any accurate comparison. However, at low doses no loss was detected.

FURTHER STUDIES ON A THYROID STIMULATING FACTOR IN CRUDE CHORIONIC GONADOTROPHIN PREPARATIONS AND IN URINE

1967 ◽  
Vol 55 (4) ◽  
pp. 600-610 ◽  
Author(s):  
A. Burger ◽  
R. Kunz
Keyword(s):  
Biological Activity ◽  
Dose Response ◽  
Response Curve ◽  
Gel Filtration ◽  
Chorionic Gonadotrophin ◽  
Dose Response Curve ◽  
Intermediate Step ◽  
Urinary Proteins ◽  
Biological Responses ◽  
Stimulating Factor

ABSTRACT Urine from pregnant women was concentrated by a kaolin-acetone method and tested by the McKenzie bioassay (1958) for thyrotrophin (TSH). Only small responses, without any dose-response curve were found. However, more purified proteins, recovered from an intermediate step in human urinary chorionic gonadotrophin (crude HCG) purification and supplied by Organon, Holland, produced much higher biological responses, when tested in corresponding concentrations. Yet, even here, no straight dose-response curve was obtained and the responses were more prolonged at higher concentrations. As described before (Burger 1967), thyroid stimulating factor in purified human urinary chorionic gonadotrophin (TSF in HCG) produced a straight dose-response curve. In gel filtration studies, TSF in HCG together with the bulk of urinary proteins were eluted more rapidly than bovine TSH (BTSH), suggesting a higher molecular weight of TSF in HCG preparations. By double diffusion technique, uromucoid could be demonstrated immunologically in crude and in purified HCG. To explain the different biological responses in crude and purified urinary proteins in the McKenzie bioassay and the different elution patterns in gel filtration studies with TSF in HCG and TSH, the following hypothesis is advanced: In urine TSH is bound to urinary proteins, possibly to uromucoid, which interfere with its biological activity. The biological activity is regained by purification.

The Risk to Health From Exposure to Low Doses of Ionising Radiation

2003 ◽  
Author(s):  
Richard Wakeford ◽  
E. Janet Tawn
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Threshold Model ◽  
Scientific Evidence ◽  
Ionising Radiation ◽  
Dose Response Curve ◽  
Threshold Dose ◽  
Radiological Protection ◽  
Low Doses ◽  
Hereditary Disorders

Controversy continues over the shape of the dose-response curve describing the risk of stochastic health effects (cancer and hereditary disorders) following exposure to low doses of ionising radiation. Radiological protection is currently based upon the assumption that the dose-response curve has no threshold and is linear in the low dose region. This position is challenged by groups suggesting either that this approach seriously underestimates the true risk at low doses or that low-level exposure results in no risk (a threshold dose exists) or even a beneficial effect (“radiation hormesis”). In this paper, we examine the epidemiological and radiobiological bases of the linear no-threshold model and some of the alternatives that have been proposed. We conclude that the evidence for a material deviation from a linear no-threshold dose-response relationship at low doses is not persuasive and that the standard model provides the most parsimonious description of the available scientific evidence.

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.

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%.

scholarly journals How Desirable Are Your IC50s?

2010 ◽  
Vol 15 (10) ◽  
pp. 1183-1193 ◽  
Author(s):  
Gaia V. Paolini ◽  
Richard A. Lyons ◽  
Philip Laflin
Keyword(s):  
Experimental Data ◽  
Biological Activity ◽  
Drug Discovery ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Response Curves ◽  
Dose Response Curves ◽  
Combine Information

Dose-response curves, resulting in estimates of endpoints such as the IC50, are fundamental to drug discovery. However, some estimates are more reliable than others. It is important to know just how reliable an estimate is if we want to base decisions on it or use it in further modeling. In this study, the authors propose a new measure of endpoint reliability, based on the concept of desirability first introduced by Harrington. The solution is not dependent on the application used to analyze the experimental data, provided a number of parameters to characterize the dose-response curve are available. The authors show how this score can be used as an objective and consistent measure to rank screening results, combine information from groups of experiments, and determine optimal levels of characterization of a compound’s biological activity.

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.

HYPERTROPHIC ADRENALS AND THEIR RESPONSE TO STRESS AFTER LESIONS IN THE MEDIAN EMINENCE OF TOTALLY HYPOPHYSECTOMIZED PIGEONS

1961 ◽  
Vol 37 (4) ◽  
pp. 565-576 ◽  
Author(s):  
Richard A. Miller
Keyword(s):  
Dose Response ◽  
Median Eminence ◽  
Response Curve ◽  
Liver Parenchyma ◽  
Dose Response Curve ◽  
Pars Distalis ◽  
Adrenal Enlargement ◽  
Response To Stress ◽  
Lethal Doses ◽  
Chromaffin Tissue

ABSTRACT Four per cent formaldehyde, insulin, or epinephrine in oil was injected for 5 days into pigeons subjected to varying degrees of hypophysectomy alone or together with large lesions in the median eminence and hypothalamus. Adrenals atrophied after the removal of the pars distalis alone or together with the neurohypophysis in untreated pigeons but showed markedly hypertrophic interrenal tissue (cortex in mammals) after treatment with formaldehyde or insulin. The slope of the dose-response curve was similar in operated and unoperated pigeons. The accumulation of bile in the liver parenchyma, which may occur after removal of the pars distalis, is an endogenous stress which was associated regularly with adrenal hypertrophy. After very large lesions of the median eminence and ventral hypothalamus in addition to total hypophysectomy, adrenals hypertrophied rather than atrophied, and the response to formaldehyde paralleled that in intact and »hypohysectomized« pigeons. Interrenal tissue was stimulated regularly; chromaffin tissue was partially degranulated, sometimes showed hyperplasia with colchicine, but only occasionally appeared hypertrophied. Epinephrine in nearly lethal doses caused only minimal adrenal enlargement. After adrenal denervation followed by hypophysectomy, the adrenals were still stimulated by formaldehyde. It appears that the interrenal tissue of the pigeon responds to a humoral stimulus not of hypophyseal origin in the absence of the hypophyseal-hypothalamic system.

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