Hormesis of 2,4-D Choline Salt in Biometric Aspects of Cotton

Plant hormesis is a phenomenon that involves the presence of toxic compounds at high doses but can be beneficial at low doses. Thus, the aim of this study was to use dose-response curves to assess the effect of hormesis caused by sub-toxic of 2,4-D choline herbicide on biometric variables of cotton plants. The study adopted a completely randomized experimental design with seven replications, and the treatments consisted of nine fractions of the average rate indicated on the 2,4-D choline salt herbicide label: 0 (control); 0.4275; 0.855; 1.71; 3.42; 8.55; 17.1; 34.2 and 68.4 g ae ha-1 applied at phenological stages V4 or B4 of cotton plants. The plants were assessed for the main morphological parameters. The results were subjected to analysis of variance and, when significant, the hormesis model was tested aiming to describe the dose-response curves with low rates stimulation. The maximum hormesis effect for the variables plant height and number of leaves in cotton plants at stage V4 was estimated, in due order, for sub-doses between 1.14 and 3.02 and 1.37 and 5.54 g ae ha-1 of 2,4-D choline. The hormesis effect was not significant for total dry matter production when 2,4-D choline was applied at stage V4, irrespective of the year of study. Sub-doses between 0.855 and 1.71 g ae ha-1 of 2,4-D choline salt applied at stage B4 caused hormesis in the height, number of leaves, shoots dry matter and total dry matter of cotton plants.

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Investigating quartz optically stimulated luminescence dose–response curves at high doses

Radiation Measurements ◽

10.1016/j.radmeas.2010.07.010 ◽

2010 ◽

Vol 45 (9) ◽

pp. 975-984 ◽

Cited By ~ 39

Author(s):

Sally E. Lowick ◽

Frank Preusser ◽

Ann G. Wintle

Keyword(s):

Dose Response ◽

Optically Stimulated Luminescence ◽

Response Curves ◽

Dose Response Curves ◽

High Doses

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Effects of inhaled substance P on airway responsiveness to methacholine in asthmatic subjects in vivo

Journal of Applied Physiology ◽

10.1152/jappl.1994.77.3.1325 ◽

1994 ◽

Vol 77 (3) ◽

pp. 1325-1332 ◽

Cited By ~ 56

Author(s):

D. Cheung ◽

H. van der Veen ◽

J. den Hartigh ◽

J. H. Dijkman ◽

P. J. Sterk

Keyword(s):

Substance P ◽

Dose Response ◽

Forced Expiratory Volume ◽

Maximal Response ◽

Response Curves ◽

Airway Narrowing ◽

Dose Response Curves ◽

High Doses

We tested the hypothesis that the inhaled tachykinin substance P (SP) can induce hyperresponsiveness to methacholine in asthmatic subjects in vivo. Nine atopic nonsmoking asthmatic males with normal forced expiratory volume in 1 s (FEV1; > 80% predicted) and increased methacholine sensitivity [provocative concn causing 20% fall in FEV1 (PC20) < 8 mg/ml] participated in a two-period placebo-controlled crossover study. Dose-response curves to SP (0.25–8 mg/ml) and placebo were recorded on 2 randomized days at least 1 wk apart, and methacholine tests were done 24 h before and 2 and 24 h after these challenges. The responses were measured by FEV1 (%fall from baseline). The position of the methacholine dose-response curves was expressed by the PC20 FEV1 and by the maximal response by the plateau level (MFEV1). SP caused a dose-dependent fall in FEV1 (P < 0.001). There was a slight increase in the PC20 FEV1 at 2 and 24 h, which was not significantly different between placebo and SP. Similarly, there was a reduction in MFEV1 at 2 h after both pretreatments. However, at 24 h after SP inhalation, MFEV1 increased compared with placebo. These changes in MFEV1 were significantly different between SP and placebo by 5.2 +/- 2.2% fall (SE) (P < 0.05). We conclude that 1) a bronchoconstrictive dose of SP, compared with placebo, enhances maximal airway narrowing to methacholine in asthma 24 h after inhalation and 2) tolerance develops to high doses of inhaled methacholine. These findings are suggestive of a role of SP in causing excessive airway narrowing in asthma by inflammatory mechanisms.

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Relative Hypertrehalosaemic Activities of Naturally Occurring Neuropeptides from the AKH/RPCH Family

Zeitschrift für Naturforschung C ◽

10.1515/znc-1986-0312 ◽

1986 ◽

Vol 41 (3) ◽

pp. 315-320 ◽

Cited By ~ 32

Author(s):

Gerd Gäde

Keyword(s):

Dose Response ◽

Stick Insect ◽

Amino Acid Sequences ◽

Maximal Response ◽

Adipokinetic Hormone ◽

Response Curves ◽

Migratory Locust ◽

Naturally Occurring ◽

Dose Response Curves ◽

High Doses

Dose-response curves for the ability to increase blood carbohydrates of the cockroach are compared for various naturally occurring neuropeptides from the corpus cardiacum of different insect species. The peptides investigated are the (decapeptides) locust adipokinetic hormone I (AKH I) and stick insect hypertrehalosaem ic factor II. as well as the (octapeptides) cockroach hypertrehalosaemic horm ones I and II (M I and M II), adipokinetic hormone II from the migratory locust (AKH II-L), and the crustacean red pigment-concentrating hormone (RPCH ). The data show clearly that M I and M II display almost identical dose-response curves with a maximal response at about 5 pmol and ED50 values (the amount of peptide which is needed to produce 50% of the hypertrehalosaemic response) of 1.9 and 1.8 pmol. respectively. The stick insect peptide is remarkably more potent (ED 50 value: 0.9 pmol), but the other decapeptide. AKH I, gives only about a 70% response com pared with M I and M II. as does the octapeptide RPCH. The ED 50 values of those peptides are 5.9 and 4.5 pmol, respectively. Biological activity after injection of AKH II-L, which lacks a proline residue in the molecule, is only measurable at pharmacologically high doses. An attempt is made to relate the observed differences in the doseresponse relationships to the amino acid sequences of the neuropeptides.

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

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647705 ◽

1974 ◽

Vol 32 (02/03) ◽

pp. 356-365 ◽

Cited By ~ 12

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.

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BIOASSAY OF THYROID HORMONE USING HYPOTHYROID TADPOLES

Acta Endocrinologica ◽

10.1530/acta.0.0410143 ◽

1962 ◽

Vol 41 (1) ◽

pp. 143-153 ◽

Cited By ~ 2

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.

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Dose Response Curves for Microwave Ablation in the Cardioplegia-Arrested Porcine Heart

The Heart Surgery Forum ◽

10.1532/hsf98.20051011 ◽

2005 ◽

Vol 8 (4) ◽

pp. E269-E274 ◽

Cited By ~ 1

Author(s):

Sydney L. Gaynor ◽

Gregory D. Byrd ◽

Michael D. Diodato ◽

Yosuke Ishii ◽

Anson M. Lee ◽

...

Keyword(s):

Dose Response ◽

Microwave Ablation ◽

Response Curves ◽

Porcine Heart ◽

Dose Response Curves

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Modeling Nonmonotonic Dose-Response Curves

10.21236/ada391664 ◽

2001 ◽

Author(s):

Quinton J. Nottingham ◽

Jeffrey B. Birch ◽

Barry A. Bodt

Keyword(s):

Dose Response ◽

Response Curves ◽

Dose Response Curves

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Comment Concerning the Effects of Light Intensity on Melatonin Suppression in the Review “Light Modulation of Human Clocks, Wake, and Sleep” by A. Prayag et al.

Clocks & Sleep ◽

10.3390/clockssleep3010011 ◽

2021 ◽

Vol 3 (1) ◽

pp. 181-188

Author(s):

Peter Bracke ◽

Eowyn Van de Putte ◽

Wouter R. Ryckaert

Keyword(s):

Phase Shift ◽

Light Intensity ◽

Dose Response ◽

Light Modulation ◽

Response Curves ◽

Practical Applications ◽

Circadian Phase ◽

Melatonin Suppression ◽

Dose Response Curves ◽

Circadian Phase Shift

Dose-response curves for circadian phase shift and melatonin suppression in relation to white or monochromatic nighttime illumination can be scaled to melanopic weighed illumination for normally constricted pupils, which makes them easier to interpret and compare. This is helpful for a practical applications.

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