scholarly journals Correlation of Chemical Analysis of Residual Levels of Aminocyclopyrachlor in Soil to Biological Responses of Alfalfa, Cotton, Soybean, and Sunflower

2011 ◽  
Vol 25 (2) ◽  
pp. 239-244 ◽  
Author(s):  
Stephen D. Strachan ◽  
Sergio C. Nanita ◽  
Marc Ruggiero ◽  
Mark S. Casini ◽  
Kathleen M. Heldreth ◽  
...  
Keyword(s):  
Dose Response ◽  
High Performance ◽  
Limit Of Detection ◽  
Soil Analysis ◽  
Plant Response ◽  
Response Analysis ◽  
Plant Responses ◽  
Response Curves ◽  
Additional Species ◽  
Rotational Crop

Researchers, product registration personnel, and growers desire the ability to chemically detect residual amounts of herbicides in soil at concentrations below those necessary to cause phytotoxicity to sensitive nontarget or rotational crop plants. Alfalfa, cotton, soybean, and sunflower, crops sensitive to low concentrations of aminocyclopyrachlor in soil, were planted at field test sites approximately 1 yr after aminocyclopyrachlor methyl was applied. Soil samples were collected when rotational crops were planted and were analyzed for aminocyclopyrachlor by a method based on high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS), with a limit of detection (LOD) of 0.1 part per billion (ppb) (soil oven-dry weight basis). Loglogistic dose–response analysis correlated visual phytotoxic plant responses to residual concentrations of aminocyclopyrachlor in the soil. Concentrations of aminocyclopyrachlor estimated to cause 25% phytotoxicity to alfalfa, cotton, soybean, and sunflower were 5.4, 3.2, 2.0, and 6.2 ppb, respectively, 20 to 60 times greater than the LOD of the analytical method available for soil analysis. Results from these studies suggest this HPLC/MS/MS method of analysis can be used to indicate potential risk and severity of plant response for alfalfa, cotton, soybean, and sunflower, and for other plant species once dose–response curves for these additional species are established. This chemical assay may be particularly important if researchers desire to study the concentration, movement, and dissipation of aminocyclopyrachlor in soil or as part of a forensic investigation to better understand the cause of an unanticipated or undesirable plant response.

scholarly journals Nonmonotonic Pathway Gene Expression Analysis Reveals Oncogenic Role of p27/Kip1 at Intermediate Dose

2017 ◽  
Vol 16 ◽  
pp. 117693511774013 ◽  
Author(s):  
Hien H Nguyen ◽  
Susan C Tilton ◽  
Christopher J Kemp ◽  
Mingzhou Song
Keyword(s):  
Gene Expression ◽  
Pathway Analysis ◽  
Dose Response ◽  
Response Analysis ◽  
Response Curves ◽  
Cancer Pathways ◽  
Pathway Gene ◽  
Mechanistic Basis ◽  
Functional Pathway ◽  
Squamous Cell Papilloma

The mechanistic basis by which the level of p27Kip1 expression influences tumor aggressiveness and patient mortality remains unclear. To elucidate the competing tumor-suppressing and oncogenic effects of p27Kip1 on gene expression in tumors, we analyzed the transcriptomes of squamous cell papilloma derived from Cdkn1b nullizygous, heterozygous, and wild-type mice. We developed a novel functional pathway analysis method capable of testing directional and nonmonotonic dose response. This analysis can reveal potential causal relationships that might have been missed by other nondirectional pathway analysis methods. Applying this method to capture dose-response curves in papilloma gene expression data, we show that several known cancer pathways are dominated by low-high-low gene expression responses to increasing p27 gene doses. The oncogene cyclin D1, whose expression is elevated at an intermediate p27 dose, is the most responsive gene shared by these cancer pathways. Therefore, intermediate levels of p27 may promote cellular processes favoring tumorigenesis—strikingly consistent with the dominance of heterozygous mutations in CDKN1B seen in human cancers. Our findings shed new light on regulatory mechanisms for both pro- and anti-tumorigenic roles of p27Kip1. Functional pathway dose-response analysis provides a unique opportunity to uncover nonmonotonic patterns in biological systems.

Log-Logistic Analysis of Herbicide Dose-Response Relationships

1995 ◽  
Vol 9 (2) ◽  
pp. 218-227 ◽  
Author(s):  
Steven S. Seefeldt ◽  
Jens Erik Jensen ◽  
E. Patrick Fuerst
Keyword(s):  
Dose Response ◽  
Logistic Model ◽  
Response Analysis ◽  
Analysis Method ◽  
Weed Science ◽  
Response Curves ◽  
Herbicide Resistant ◽  
Logistic Analysis ◽  
Analysis Methods ◽  
The Difference

Dose-response studies are an important tool in weed science. The use of such studies has become especially prevalent following the widespread development of herbicide resistant weeds. In the past, analyses of dose-response studies have utilized various types of transformations and equations which can be validated with several statistical techniques. Most dose-response analysis methods 1) do not accurately describe data at the extremes of doses and 2) do not provide a proper statistical test for the difference(s) between two or more dose-response curves. Consequently, results of dose-response studies are analyzed and reported in a great variety of ways, and comparison of results among various researchers is not possible. The objective of this paper is to review the principles involved in dose-response research and explain the log-logistic analysis of herbicide dose-response relationships. In this paper the log-logistic model is illustrated using a nonlinear computer analysis of experimental data. The log-logistic model is an appropriate method for analyzing most dose-response studies. This model has been used widely and successfully in weed science for many years in Europe. The log-logistic model possesses several clear advantages over other analysis methods and the authors suggest that it should be widely adopted as a standard herbicide dose-response analysis method.

A Dose-Response Analysis of Nicotine Sensitization in Adolescent Rats D2-Primed as Neonates

2010 ◽  
Author(s):  
Elizabeth A. Hanchak ◽  
Meredith L. Smith ◽  
Jessie J. Smith ◽  
Marla K. Perna ◽  
Russell W. Brown
Keyword(s):  
Dose Response ◽  
Response Analysis ◽  
Adolescent Rats

ENCORE: A weight-based exacerbation dose response analysis of mepolizumab in severe asthma with eosinophilic phenotype

Pneumologie ◽  
2017 ◽  
Vol 71 (S 01) ◽  
pp. S1-S125
Author(s):  
I Pouliquen ◽  
D Austin ◽  
N Gunsoy ◽  
SW Yancey
Keyword(s):  
Severe Asthma ◽  
Dose Response ◽  
Response Analysis

Dose-response Curves in the Fibrin Plate Assay Fibrinolytic Activity of Proteases

1974 ◽  
Vol 32 (02/03) ◽  
pp. 356-365 ◽  
Author(s):  
F Haverkate ◽  
D. W Traas
Keyword(s):  
Dose Response ◽  
Fibrinolytic Activity ◽  
Enzyme Concentration ◽  
Response Curves ◽  
Agar Gel ◽  
Porcine Tissue ◽  
Plate Assay ◽  
Fibrin Plate ◽  
Different Types ◽  
Dose Response Curves

SummaryIn the fibrin plate assay different types of relationships between the dose of applied proteolytic enzyme and the response have been previously reported. This study was undertaken to determine whether a generally valid relationship might exist.Trypsin, chymotrypsin, papain, the plasminogen activator urokinase and all of the microbial proteases investigated, including brinase gave a linear relationship between the logarithm of the enzyme concentration and the diameter of the circular lysed zone. A similar linearity of dose-response curves has frequently been found by investigators who used enzyme plate assays with substrates different from fibrin incorporated in an agar gel. Consequently, it seems that this linearity of dose-response curves is generally valid for the fibrin plate assay as well as for other enzyme plate bioassays.Both human plasmin and porcine tissue activator of plasminogen showed deviations from linearity of semi-logarithmic dose-response curves in the fibrin plate assay.

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.

BIOASSAY OF THYROID HORMONE USING HYPOTHYROID TADPOLES

1962 ◽  
Vol 41 (1) ◽  
pp. 143-153 ◽  
Author(s):  
U. Henriques
Keyword(s):  
Thyroid Hormone ◽  
Dose Response ◽  
Developmental Rate ◽  
Response Curves ◽  
Sodium Salts ◽  
Dose Response Curves

ABSTRACT A bioassay of thyroid hormone has been developed using Xenopus larvae made hypothyroid by the administration of thiourea. Only tadpoles of uniform developmental rate were used. Thiourea was given just before the metamorphotic climax in concentrations that produced neoteni in an early metamorphotic stage. During maintained thiourea neotoni, 1-thyroxine and 1-triiodothyronine were added as sodium salts to the water for three days and at the end of one week the stage of metamorphosis produced was determined. In this way identical dose-response curves were obtained for the two compounds. No qualitative differences between their effects were noted except that triiodothyronine seemed more toxic than thyroxine in equivalent doses. Triiodothyronine was found to be 7–12 times as active as thyroxine.

ÜBER DIE ANTAGONISTISCHE WIRKUNG VON TRIJODTHYRONIN UND PROGESTERON AUF DEN PREDNISOLONEFFEKT AM EPIPHYSENKNORPEL (PRÜFUNG DER REISSFESTIGKEIT)

1963 ◽  
Vol 42 (1) ◽  
pp. 29-38 ◽  
Author(s):  
L. Ther ◽  
H. Schramm ◽  
G. Vogel
Keyword(s):  
Tensile Strength ◽  
Dose Response ◽  
Single Injection ◽  
Relative Effectiveness ◽  
Prednisolone Acetate ◽  
Response Curves ◽  
Deoxycorticosterone Acetate ◽  
Weight Range ◽  
Diuretic Action ◽  
Maximal Load

ABSTRACT Longitudinal tension exerted on a killed rat's femur results always in rupture on the same place viz: the distal epiphyseal line. The power required to produce this effect can be measured with a simple dynamometer. The tensile strength increases with advancing age and during exsiccation (thirst). In untreated rats (weight range 100–120 g) this value amounts to about 1.5–1.8 kg. Tensile strength of the femoral epiphyseal line may be influenced by hormones. Corticosteroids such as prednisolone acetate and cortisol acetate increase the level of maximal load to more than 2.0 kg. In general the effect of a single injection reaches a climax after 48 hours. Dose-response-curves can be established and relative effectiveness may be gathered therefrom. Deoxycorticosterone acetate likewise increases tensile strength in spite of the fact that contrary to prednisolone exhibiting diuretic action this compound has a water retaining effect. Triiodothyronine and progesterone when given alone produce a slight decrease in tensile strength. The effect of prednisolone when given simultaneously with one of these two compounds is antagonized: this phenomenon is more pronounced in the case of triiodothyronine.

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