Limpograss (Hemarthria altissima) Tolerance to Hexazinone

2017 ◽  
Vol 31 (5) ◽  
pp. 682-688 ◽  
Author(s):  
Cody A. Lastinger ◽  
José Luiz C. S. Dias ◽  
Brent A. Sellers ◽  
Jason A. Ferrell ◽  
Maria L. Silveira ◽  
...  
Keyword(s):  
Dose Response ◽  
Regression Models ◽  
Field Trials ◽  
Mass Reduction ◽  
Quadratic Regression ◽  
Viable Option ◽  
Response Curves ◽  
Hemarthria Altissima ◽  
Significant Difference ◽  
Rainfall Patterns

Field trials were conducted in 2013 and 2014 to investigate the tolerance of limpograss to increasing rates of hexazinone. Dose-response curves were generated using linear and quadratic regression models to determine the hexazinone estimated dose (ED) required to provide 10% (ED10) and 20% (ED20) of visual injury and herbage mass reduction. The ED10and ED20for visual estimates of injury were estimated to be 0.05 and 0.14 kg ai ha-1at 60 d after treatment (DAT). Regarding forage herbage mass reduction, the ED10and ED20were estimated to be 0.07 and 0.19 kg ai ha-1in 2013, whereas in 2014, the ED10and ED20were estimated to be 0.03 and 0.06 kg ai ha-1, respectively. The significant difference in herbage mass reduction between 2013 and 2014 was likely due to rainfall patterns, which possibly promoted hexazinone leaching in 2013 and consequently, less activity. Overall, hexazinone resulted in high degrees of limpograss injury across all response variables in both years; therefore, smutgrass control in limpograss pastures with hexazinone may not be a viable option. The presence or absence of smutgrass should be considered before limpograss establishment as there is no viable herbicide to selectively remove smutgrass from limpograss swards.

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.

The guinea pig tracheobronchial spiral strip: responses to selected agonists

1978 ◽  
Vol 56 (5) ◽  
pp. 823-827 ◽  
Author(s):  
C. J. Hanna ◽  
S. H. Roth
Keyword(s):  
Regression Analysis ◽  
Guinea Pig ◽  
Dose Response ◽  
Effective Concentration ◽  
Relative Order ◽  
Response Curves ◽  
Response Data ◽  
Significant Difference ◽  
Dose Dependent

The guinea pig tracheal spiral strip is a useful preparation for studying bronchoconstrictor and bronchodilator compounds. Employing a simple and rapid modification of this technique, experiments were performed in vitro to quantitate the effects of selected bronchospastic agents on guinea pig tracheobronchial smooth muscle. Three sections of the main airways were prepared from each animal: an upper tracheal, a lower tracheal, and a bronchial segment. The dose-dependent contractile responses of the three tissue segments were determined for carbachol, acetylcholine, histamine, 5-hydroxytryptamine, and bradykinin, Differences were observed amongst the agonists in magnitudes of contraction, effective concentration ranges, and slopes of dose–response curves. ED25, ED50, and ED75, values were calculated from regression analysis of dose–response data. The relative order for these agents to produce maximum contractions was found to be carbachol [Formula: see text] acetylcholine > histamine > 5-hydroxytryptamine > bradykinin. Furthermore, it was found that there was no significant difference between the three tissue segments in their responses to the various agonists.

Methacholine dose-response curves in normal and asthmatic man: Effect of starting conductance and pharmacological antagonism

1984 ◽  
Vol 66 (6) ◽  
pp. 665-673 ◽  
Author(s):  
K. F. Chung ◽  
P. D. Snashall
Keyword(s):  
Dose Response ◽  
Normal Subjects ◽  
Small Degree ◽  
Response Curves ◽  
Significant Difference ◽  
Positive Linear Correlation ◽  
Dose Response Curves ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Different Doses

1. The bronchial response of 11 normal and ten stable asthmatic subjects to increasing concentrations of methacholine aerosol was assessed by serial measurements of specific airways conductance (scaw) in a body plethysmograph. 2. Cumulative log dose-response curves were constructed. The threshold provocative dose of methacholine needed to cause a 35% fall in starting sCaw (pD35) and the steepest slope of the response were measured from each curve. 3. On separate days subjects were premedicated with 0.9% NaCl solution (control) in duplicate, chlorpheniramine, salbutamol and atropine, the last-named at two different doses, one twice the other. 4. Asthmatic subjects had a lower mean PD35 and a lower mean slope than normal subjects. 5. Pretreatment with salbutamol resulted in a greater increase in sGaw than after atropine but caused a smaller increase in PD35 in both groups. There was a dose-dependent increase in PD3s after the two doses of atropine, but no significant difference in bronchodilatation between doses. Mean steepest slope approximately doubled in these three sets of challenges. 6. Chlorpheniramine caused a small degree of bronchodilatation and there was a non-significant increase in mean PD3s and in mean steepest slope in both normal and asthmatic groups. 7. There was a positive linear correlation between starting sGaw and steepest slope in each group of premedicated challenges, such that when

scholarly journals Is Response to Genotoxic Stress Similar in Populations of African and European Ancestry? A Study of Dose-Response After in vitro Irradiation

2021 ◽  
Vol 12 ◽  
Author(s):  
Mamadou Soumboundou ◽  
Julien Dossou ◽  
Yossef Kalaga ◽  
Innocent Nkengurutse ◽  
Ibrahima Faye ◽  
...  
Keyword(s):  
Chromosomal Aberrations ◽  
Dose Response ◽  
Genotoxic Stress ◽  
European Ancestry ◽  
Response Curves ◽  
Blood Samples ◽  
Dicentric Chromosomes ◽  
Significant Difference ◽  
Dose Response Curves

Background: Exposure to genotoxic stress such as radiation is an important public health issue affecting a large population. The necessity of analyzing cytogenetic effects of such exposure is related to the need to estimate the associated risk. Cytogenetic biological dosimetry is based on the relationship between the absorbed dose and the frequency of scored chromosomal aberrations. The influence of confounding factors on radiation response is a topical issue. The role of ethnicity is unclear. Here, we compared the dose-response curves obtained after irradiation of circulating lymphocytes from healthy donors of African and European ancestry.Materials and Methods: Blood samples from six Africans living in Africa, five Africans living in Europe, and five Caucasians living in Europe were exposed to various doses (0–4 Gy) of X-rays at a dose-rate of 0.1 Gy/min using an X-RAD320 irradiator. A validated cohort composed of 14 healthy Africans living in three African countries was included and blood samples were irradiated using the same protocols. Blood lymphocytes were cultured for 48 h and chromosomal aberrations scored during the first mitosis by telomere and centromere staining. The distribution of dicentric chromosomes was determined and the Kruskal-Wallis test was used to compare the dose-response curves of the two populations.Results: No spontaneous dicentric chromosomes were detected in African donors, thus establishing a very low background of unstable chromosomal aberrations relative to the European population. There was a significant difference in the dose response curves between native African and European donors. At 4 Gy, African donors showed a significantly lower frequency of dicentric chromosomes (p = 8.65 10–17), centric rings (p = 4.0310–14), and resulting double-strand-breaks (DSB) (p = 1.32 10–18) than European donors. In addition, a significant difference was found between African donors living in Europe and Africans living in Africa.Conclusion: This is the first study to demonstrate the important role of ethnic and environmental factors that may epigenetically influence the response to irradiation. It will be necessary to establish country-of-origen-specific dose response curves to practice precise and adequate biological dosimetry. This work opens new perspective for the comparison of treatments based on genotoxic agents, such as irradiation.

Geographic Regional Differences in Rocuronium Bromide Dose–Response Relation and Time Course of Action

2006 ◽  
Vol 104 (5) ◽  
pp. 950-953 ◽  
Author(s):  
Ashraf A. Dahaba ◽  
Seth I. Perelman ◽  
David M. Moskowitz ◽  
Henry L. Bennett ◽  
Aryeh Shander ◽  
...  
Keyword(s):  
Dose Response ◽  
Time Course ◽  
Neuromuscular Block ◽  
Chinese Patients ◽  
Ambient Conditions ◽  
Response Curves ◽  
Rocuronium Bromide ◽  
Duration Of Action ◽  
Significant Difference ◽  
Geographic Regions

Background Geographic location is not acknowledged as a stratifying factor that can directly affect drug potency, because drugs are still licensed with the same recommended dose for different geographic regions. The aim of the current study was to compare the potency and duration of action of rocuronium bromide in 54 patients in three countries with different life habits, diet, and ambient conditions, namely white Austrians, white North Americans, and Han Chinese in China. Methods Neuromuscular block of six consecutive 50-microg/kg rocuronium incremental doses followed by 300 microg/kg was evaluated using the Relaxometer mechanomyograph (Groningen University, Groningen, Holland). Dose-response curves were created using log-dose-probit transformation. The authors compared rocuronium bromide ED50, ED90, and ED95 (effective doses required for 50%, 90%, and 95% first twitch depression, respectively) as well as Dur25 and Dur0.8 (times from last incremental dose administration until 25% first twitch and 0.8 train-of-four ratio recovery, respectively) in patients of the three countries. Results Rocuronium ED50, ED90, and ED95 were significantly higher in Austrian patients (258 +/- 68, 530 +/- 159, and 598 +/- 189 microg/kg) and Chinese patients (201 +/- 59, 413 +/- 107, and 475 +/- 155 microg/kg) compared with American patients (148 +/- 48, 316 +/- 116, and 362 +/- 149 microg/kg, respectively). Dur25 and Dur0.8 were significantly shorter in Austrian patients (22.3 +/- 5.5 and 36.9 +/- 12.8 min) and Chinese patients (30.4 +/- 7.5 and 45.7 +/- 15.9 min) compared with American patients (36.7 +/- 8.5 and 56.2 +/- 16.7 min, respectively). Conclusions The authors demonstrated a significant difference in rocuronium potency and duration of action among patients in the three countries. Larger studies are required for determining dosage recommendations for different geographic regions.

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.

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.

STUDIES ON SULFATION FACTOR (SF) ACTIVITY OF HUMAN SERUM

1960 ◽  
Vol XXXV (III) ◽  
pp. 381-396 ◽  
Author(s):  
Sven Almqvist
Keyword(s):  
Human Serum ◽  
Normal Serum ◽  
Treatment Level ◽  
Response Curves ◽  
Normal Children ◽  
Significant Difference ◽  
Human Sera ◽  
Normal Humans ◽  
Pre Treatment ◽  
Dose Levels

ABSTRACT The sulfation factor (SF) activity of human sera has been estimated using a modification of the method of Daughaday et al. (1959). Each assay was statistically evaluated. The method had a mean precision of 0.14 and, used as an assay of GH of human serum, a sensitivity in three pituitary dwarfs of 0.1 to 0.6 μg of HGH/ml of serum. SF activity was found at all ages between 1 month and 75 years. There was a significantly lower mean SF activity below the age of half a year. Three cases of pituitary dwarfism had significantly low SF activities of sera. There was no significant difference between the SF activities of sera from untreated pituitary dwarfs and the sera from normal children below half a year of age. Dose-response curves with large volumes of sera from pituitary dwarfs and small volumes of sera from normal humans had the same slopes. Four mg of HGH prepared according to the method of Li & Papkoff (1956) resulted in a normal serum SF activity in each of the three dwarfs. A significant (P < 0.01) linear relationship was found between the concentration of SF activity of sera from these subjects and the logarithm of the dose of HGH given with dose levels of 1, 2 and 4 mg daily for three days. The decline of serum SF activity to the pre-treatment level following HGH in one dwarf suggested a half life not different from that indicated by others for growth hormone.

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