EFFECTS OF OXYTOCIN ON THE UTERINE RESPONSE TO ELECTRICAL STIMULATION

1962 ◽  
Vol 41 (2) ◽  
pp. 161-169 ◽  
Author(s):  
N. Wiqvist ◽  
I. Wiqvist ◽  
C. A. Fielitz ◽  
R. Caldeyro-Barcia
Keyword(s):  
Electrical Stimulation ◽  
Dose Response ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Rat Uterus ◽  
Experimental Conditions ◽  
Minimum Effective Concentration ◽  
Low Concentrations ◽  
Tenfold Increase

ABSTRACT The enhancing effect of low concentrations of oxytocin on the uterine response to electrical stimulation was measured »in vitro« on the superfused rat uterus. In order to reduce the incidence of spontaneous motility, the pacemaker areas were excised from the uterine strip and the calcium concentration was lowered to 1/5th of that of a normal Krebs solution. Under these experimental conditions, it was found that the minimum effective concentration of oxytocin was generally between 5 and 20 μU/ml. A graded dose-response relationship was obtained within a range of concentrations from 5 to 50 μU/ml; within this range, a tenfold increase of the oxytocin concentration caused a five-fold augmentation of the uterine response. The possible use of this method for the bioassay of oxytocin is discussed. Both the range of oxytocin concentrations employed as well as the dose-response relationship found in this investigation for the superfused rat uterus bear a suggestive resemblance to the results published by others for the response of the pregnant human uterus »in situ« to the intravenous infusion of oxytocin.

scholarly journals Comparative Effectiveness of Calabadion and Sugammadex to Reverse Non-depolarizing Neuromuscular-blocking Agents

2015 ◽  
Vol 123 (6) ◽  
pp. 1337-1349 ◽  
Author(s):  
Friederike Haerter ◽  
Jeroen Cedric Peter Simons ◽  
Urs Foerster ◽  
Ingrid Moreno Duarte ◽  
Daniel Diaz-Gil ◽  
...  
Keyword(s):  
Dose Response ◽  
Urine Analysis ◽  
Ex Vivo ◽  
Neuromuscular Blocking ◽  
Response Relationship ◽  
Binding Assays ◽  
Dose Response Relationship ◽  
Competition Binding ◽  
Relationship Of

Abstract Background The authors evaluated the comparative effectiveness of calabadion 2 to reverse non-depolarizing neuromuscular-blocking agents (NMBAs) by binding and inactivation. Methods The dose–response relationship of drugs to reverse vecuronium-, rocuronium-, and cisatracurium-induced neuromuscular block (NMB) was evaluated in vitro (competition binding assays and urine analysis), ex vivo (n = 34; phrenic nerve hemidiaphragm preparation), and in vivo (n = 108; quadriceps femoris muscle of the rat). Cumulative dose–response curves of calabadions, neostigmine, or sugammadex were created ex vivo at a steady-state deep NMB. In living rats, the authors studied the dose–response relationship of the test drugs to reverse deep block under physiologic conditions, and they measured the amount of calabadion 2 excreted in the urine. Results In vitro experiments showed that calabadion 2 binds rocuronium with 89 times the affinity of sugammadex (Ka = 3.4 × 109 M−1 and Ka = 3.8 × 107 M−1). The results of urine analysis (proton nuclear magnetic resonance), competition binding assays, and ex vivo study obtained in the absence of metabolic deactivation are in accordance with an 1:1 binding ratio of sugammadex and calabadion 2 toward rocuronium. In living rats, calabadion 2 dose-dependently and rapidly reversed all NMBAs tested. The molar potency of calabadion 2 to reverse vecuronium and rocuronium was higher compared with that of sugammadex. Calabadion 2 was eliminated renally and did not affect blood pressure or heart rate. Conclusions Calabadion 2 reverses NMB induced by benzylisoquinolines and steroidal NMBAs in rats more effectively, i.e., faster than sugammadex. Calabadion 2 is eliminated in the urine and well tolerated in rats.

scholarly journals Modified method of erythropoietin (ESF) bioassay in vitro using mouse fetal liver cells. I. Effect of serum iron on 59Fe incorporation into heme

Blood ◽  
1978 ◽  
Vol 52 (3) ◽  
pp. 560-568 ◽  
Author(s):  
G de Klerk ◽  
C Kruiswijk ◽  
AA Hart ◽  
R Goudsmit
Keyword(s):  
Dose Response ◽  
Fetal Liver ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Potency Ratio ◽  
Modified Method ◽  
Human Sera ◽  
Fetal Liver Cells ◽  
Relationship Of

Abstract Investigations on the mouse fetal liver cell bioassay for erythropoietin (ESF) have revealed that iron present in test sera significantly dilutes the radiolabel (59Fe) and thus decreases 59Fe incorporation into heme. A method of correction for the influence of iron on the dose-response relationship of human sera is presented. Application of this method made it possible to assay human sera up to culture concentrations of 150 microliter/ml. It was shown that a corrected serum dose-response curve showed parallelism to the curve of an ESF standard preparation. This suggests similarity of the active principles and allows valid estimation of a potency ratio.

scholarly journals Critical Evaluation of Two Commercial Biocontrol Agents for Their Efficacy against B. cinerea under In Vitro and In Vivo Conditions in Relation to Different Abiotic Factors

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1868
Author(s):  
Gurkan Tut ◽  
Naresh Magan ◽  
Philp Brain ◽  
Xiangming Xu
Keyword(s):  
Dose Response ◽  
Abiotic Factors ◽  
Critical Evaluation ◽  
Leaf Disc ◽  
Biocontrol Agents ◽  
In Vivo Studies ◽  
Response Relationship ◽  
Dose Response Relationship

The study evaluated the dose–response relationship of two commercial microbial biocontrol agents, Bacillus subtilis and Gliocladium catenulatum, against Botrytis cinerea both in vitro and in vivo. Inoculum doses, formulation, temperature and foliar leaf part all affected the control achieved by the two BCAs. In vitro competition assays on modified PDA plates tested a range of BCA doses (log10 3–10 CFUs or spores/droplet) at 4, 10 and 20 °C on the development of B. cinerea colonies. The dose–response relationship was influenced by both the BCA formulation and temperature. In vivo studies on lettuce plants in semi-commercial greenhouses examined the BCA dose (log10 5–9 CFUs or spores/mL) for controlling B. cinerea with a high inoculum (log10 6 spores/mL). Leaf disc assays showed that the dose–response relationship was influenced by the leaf parts sampled. These results suggest that the dose–response relationship between a BCA and specific pathogen will be significantly influenced by environmental conditions, formulation and plant phyllosplane tissue.

scholarly journals The various dose-dependent effect of selenium oxide and copper oxide nanoparticles in vitro and application of the hormesis paradigm

2021 ◽  
Vol 100 (12) ◽  
pp. 1475-1480
Author(s):  
Vladimir G. Panov ◽  
Ilzira A. Minigalieva ◽  
Tatyana V. Bushueva ◽  
Elizaveta P. Artemenko ◽  
Iuliia V. Ryabova ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Dose Response ◽  
Human Fibroblast ◽  
General Pattern ◽  
General Rule ◽  
Average Diameter ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Selenium Oxide

Introduction. In vitro studies on a culture of cardiomyocytes have shown that dose-response relationships could be monotonic for some effects and non-monotonic for others. In this work, we wanted to demonstrate that these features of the dose-response relationship are a general pattern. Materials and methods. In vitro experiments were conducted on the culture of human fibroblast-like cells FLECH-104. The cytotoxicity of spherical nanoparticles of selenium oxide (SeO-NP) and copper oxide (CuO-NP) was studied with an average diameter of 51 ± 14 nm and 21 ± 4 nm, respectively. Results. SeO-NP and CuO-NP were cytotoxic for human fibroblast-like cells, as judged by a decrease in ATP-dependent luminescence. In this case, the cytotoxicity of CuO-NP was somewhat more substantial than the SeO-NP one. Our experiment revealed doses that cause both cell hypertrophy and a decrease in the size of cells and nuclei. Discussion. We observed both monotonic and different variants of the non-monotonic dose-response relationship. For the latter, it was possible to construct adequate mathematical expressions based on the generalized hormesis paradigm that we had considered earlier concerning the CdS-NP and PbS-NP cytotoxicity for cardiomyocytes. Conclusion. The general rule is the variability of the dose-response dependence types manifested in different cytotoxic effects of nanoparticles.

scholarly journals Platelet Depletion and Severity of Streptococcal Endocarditis

1998 ◽  
Vol 9 (6) ◽  
pp. 359-366 ◽  
Author(s):  
Lawrence Dall ◽  
Todd Miller ◽  
Betty Herndon ◽  
Ireneo Diez ◽  
Michelle Dew
Keyword(s):  
Platelet Count ◽  
Aortic Valve ◽  
Dose Response ◽  
Vegetation Density ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Platelet Protein ◽  
Four Levels ◽  
Platelet Depletion

OBJECTIVE: To evaluate the importance of thrombocytopenia in streptococcal endocarditis using an animal model.DESIGN: A model of human septic endocarditis was established in rats (polyethylene catheters across the aortic valve and administration ofStreptococcus sanguis, 5×107colony forming units [cfu] intravenous). Thrombocytopenia at four levels was produced by antiplatelet serum. Secondary methods of producing thrombocytopenia were also evaluated. At sacrifice (96 h after platelet depletion and 72 h after infection), vegetations were removed, weighed, diluted, plated and counted. Potential mechanisms of the dose-response relationship between vegetation density and platelet count were evaluated.SETTING: Controlled research laboratory experiments.POPULATION STUDIED: Animal models of streptococcal endocarditis.MAIN RESULTS: The bacterial density of the aortic valve vegetations significantly increased as the platelet count decreased (P=0.0007). In severely thrombocytopenic animals (two-dose antiplatelet serum), data suggest increased vegetation embolism. Platelet depletion, which was minimal with chemical methods, was produced most effectively by antithrombocyte serum. Platelet surfaces in endocarditis were found to express elevated CD62p proteins (72.7% endocarditis, 34.7% control). Platelet protein fractions were evaluated in vitro by both streptocidal (P=0.19) and phagocytosis-stimulating assays. Platelet presence in mature aortic valve vegetations averaged only about 2%.CONCLUSIONS: In platelet depletion experiments using a rat model, a dose-response relationship of peripheral circulating platelet depletion to aortic valve vegetation density was found. The mechanism relating thrombocytopenia to endocarditis severity remains unresolved.

In vitro plantlet formation from shoot-tip expiants of Fuchsia hybrida cv. Swingtime

1980 ◽  
Vol 58 (20) ◽  
pp. 2190-2192 ◽  
Author(s):  
John H. Stevenson ◽  
Robert E. Harris
Keyword(s):  
Liquid Medium ◽  
Dose Response ◽  
Fold Increase ◽  
Shoot Tips ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Plantlet Formation ◽  
Quadratic Curve ◽  
Isopentenyl Adenine

A 50-fold increase in Fuchsia hybrida cv. Swingtime was obtained every 4 weeks on B5 medium with either N6-benzylaminopurine (BAP) or N6-(Δ2-isopentenyl)adenine (2iP). The shoot tips were established and grown on B5 agar for 2 weeks and then proliferated for 4 weeks on B5 liquid medium with BAP or 2iP. The dose-response relationship for both compounds was expressed by a quadratic curve and on the average the rate of proliferation was greatest with BAP at a concentration of 3 mg/L(1.3 × 10−5 M). The proliferated shoots elongated when the cytokinin was eliminated and rooted readily on B5 medium solidified with agar.

scholarly journals In vitro production of erythropoietin by mouse fetal liver

Blood ◽  
1975 ◽  
Vol 46 (1) ◽  
pp. 85-90 ◽  
Author(s):  
JR Zucali ◽  
V Stevens ◽  
EA Mirand
Keyword(s):  
Dose Response ◽  
Active Substance ◽  
Liver Tissue ◽  
Culture Medium ◽  
Fetal Liver ◽  
Response Relationship ◽  
In Vitro Production ◽  
Dose Response Relationship ◽  
Vitro Production

Abstract Mouse fetal liver tissue has been cultured and shown to produce and release into the culture medium an erythropoietically active substance for up to 30 days of culture. Since this substance can be completely neutralized by an antiserum to erythropoietin and shows a dose-- response relationship in the plethoric mouse assay, it is suggested that the culture medium contains erythropoietin, a hormone important in the regulation of erythropoiesis. Using this procedure, we have obtained the equivalent of about 20.7 unites of erythropoietin from five T-flasks (75 sq cm) over the 30-day culture period.

Sign in / Sign up

Export Citation Format

Share Document