Phase-plot analysis of the oxytocin effect on human myometrial contractility

2009 ◽  
Vol 144 ◽  
pp. S20-S24 ◽  
Author(s):  
Joanna E. Gullam ◽  
Andrew M. Blanks ◽  
Steven Thornton ◽  
Anatoly Shmygol
Keyword(s):  
Phase Plot ◽  
Plot Analysis ◽  
Myometrial Contractility

Excitatory pathways in smooth muscle investigated by phase-plot analysis of isometric force development

1991 ◽  
Vol 261 (1) ◽  
pp. R138-R144
Author(s):  
G. A. Van Koeveringe ◽  
R. Van Mastrigt
Keyword(s):  
Smooth Muscle ◽  
Time Constant ◽  
Isometric Force ◽  
Force Development ◽  
Phase Plot ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Plot Analysis ◽  
Excitatory Pathways ◽  
Rate Limiting

Excitatory pathways in the smooth muscle of the pig urinary bladder were investigated using phase-plot analysis of isometric contractions. The phase plots, plots of the rate of change of the force as a function of the force itself, were dominated by a straight line described by the horizontal intercept (Fiso) and the vertical intercept (U). The quotient Fiso/U is a time constant that characterizes the rate-limiting step in isometric force development in the muscle. Bladder strips of 1 mm diameter were activated by electrical field stimuli, acetylcholine, potassium, and ATP in combination with selective pathway inhibitors such as verapamil, atropine, or a calcium-free solution containing ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. When pathways that depended significantly on depolarization or intracellular calcium release were selected, the time constant was significantly smaller, indicating a faster process. The results indicated that the rate-limiting step in force development was determined by the influx of extracellular calcium.

Insights into gait disorders: Walking variability using phase plot analysis, Huntington's disease

2014 ◽  
Vol 40 (4) ◽  
pp. 694-700 ◽  
Author(s):  
Johnny Collett ◽  
Patrick Esser ◽  
Hanan Khalil ◽  
Monica Busse ◽  
Lori Quinn ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Gait Disorders ◽  
Phase Plot ◽  
Plot Analysis

Impulse Encoding Mechanisms of Ganglion Cells in the Tiger Salamander Retina

1997 ◽  
Vol 78 (4) ◽  
pp. 1935-1947 ◽  
Author(s):  
J. F. Fohlmeister ◽  
R. F. Miller
Keyword(s):  
Ganglion Cells ◽  
Compartment Model ◽  
Tiger Salamander ◽  
Impulse Frequency ◽  
Whole Cell ◽  
Impulse Generation ◽  
Phase Plot ◽  
Single Compartment ◽  
Plot Analysis ◽  
Single Compartment Model

Fohlmeister, J. F. and R. F. Miller. Impulse encoding mechanisms of ganglion cells in the tiger salamander retina. J. Neurophysiol. 78: 1935–1947, 1997. A study of nerve impulse generation in ganglion cells of the tiger salamander retina is carried out through a combination of experimental and analytic approaches, including computer simulations based on a single-compartment model. Whole cell recordings from ganglion cells were obtained using a superfused retina-eyecup preparation and studied with pharmacological and electrophysiological techniques, including phase plot analysis. Experimental efforts were guided by computer simulation studies of an excitability model consisting of five voltage- or ion-gated channels, which were identified from earlier voltage-clamp data. The ion channels include sodium, calcium, and three types of potassium channels, namely the A type ( I K,A), Ca-activated potassium ( I K,Ca), and the delayed rectifier ( I K). A leakage channel was included to preserve input resistance continuity between model and experiment. Ion channel densities of Na and Ca currents ( I Na and I Ca) for the single-compartment model were independently determined from phase plot analysis. The I K and I K,A current densities were determined from the measured width of impulses. The I K,Ca was modeled to respond to Ca influx, and a variable-rate Ca-sequestering mechanism was implemented to remove cytoplasmic calcium. Impulse frequency increases when either I Ca or I K,Ca is eliminated from the model or blocked pharmacologically in whole cell recording experiments. Faithful simulations of experimental data show that the ionic currents may be grouped into small ( I K,Ca, leakage, and stimulus), and large ( I Na, I K, I A, I Ca) on the basis of their peak magnitudes throughout the impulse train. This division of the currents is reflected in their function of controlling the interspike interval (small currents) and impulse generation (large currents). Although the single-compartmental model is qualitatively successful in simulating impulse frequency behavior and its controlling mechanisms, limitations were found that specifically suggest the need to include morphological details. The spike train analysis points to a role for electrotonic currents in the control of the duration of the interspike intervals, which can be compensated by prolonged activation of g K,Ca in the single-compartment model. A detailed, multicompartmental model of the ganglion cell is presented in the companion paper.

Insights into gait disorders: Walking variability using phase plot analysis, Parkinson's disease

2013 ◽  
Vol 38 (4) ◽  
pp. 648-652 ◽  
Author(s):  
Patrick Esser ◽  
Helen Dawes ◽  
Johnny Collett ◽  
Ken Howells
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Gait Disorders ◽  
Phase Plot ◽  
Plot Analysis

In vitro effect on myometrial contractility by a combination of Bryophyllum pinnatum juice and atosiban

2017 ◽  
Author(s):  
S Santos ◽  
C Haslinger ◽  
M Hamburger ◽  
M Mennet ◽  
O Potterat ◽  
...  
Keyword(s):  
Myometrial Contractility ◽  
Vitro Effect ◽  
Bryophyllum Pinnatum

A -enriched fraction of Bryophyllum pinnatum inhibits human myometrial contractility in vitro

2019 ◽  
Author(s):  
S Santos ◽  
C Haslinger ◽  
K Kalic ◽  
MT Faleschini ◽  
M Mennet ◽  
...  
Keyword(s):  
Myometrial Contractility ◽  
Bryophyllum Pinnatum

Overpressure Identification Using The Eaton Method on The Gumai Formation of Geragai Graben, Jambi Sub Basin

2020 ◽  
Author(s):  
A. O. Marnila
Keyword(s):  
Pressure Data ◽  
Stratigraphic Sequence ◽  
Fine Grained ◽  
Marine Sedimentation ◽  
Plot Analysis ◽  
Significant Reversal ◽  
Porosity And Permeability ◽  
Upper Level ◽  
Type Data ◽  
Fine Grained Sand

Geragai graben is located in the South Sumatera Basin. It was formed by mega sequence tectonic process with various stratigraphic sequence from land and marine sedimentation. One of the overpressure indication zones in the Geragai graben is in the Gumai Formation, where the sedimentation is dominated by fine grained sand and shale with low porosity and permeability. The aim of the study is to localize the overpressure zone and to analyze the overpressure mechanism on the Gumai Formation. The Eaton method was used to determine pore pressure value using wireline log data, pressure data (RFT/FIT), and well report. The significant reversal of sonic and porosity log is indicating an overpressure presence. The cross-plot analysis of velocity vs density and fluid type data from well reports were used to analyze the causes of overpressure in the Gumai Formation. The overpressure in Gumai Formation of Geragai graben is divided into two zones, they are in the upper level and lower level of the Gumai Formation. Low overpressure have occurred in the Upper Gumai Formation and mild overpressure on the Lower Gumai Formation. Based on the analyzed data, it could be predicted, that the overpressure mechanism in the Upper Gumai Formation might have been caused by a hydrocarbon buoyancy, whereas in the Lower Gumai Formation, might have been caused by disequilibrium compaction as a result of massive shale sequence.

The Myometrium in Pregnant Women with Obesity

2020 ◽  
Vol 19 (2) ◽  
pp. 193-200
Author(s):  
Jorge A. Carvajal ◽  
Joaquín I. Oporto
Keyword(s):  
Pregnant Women ◽  
Public Health Problem ◽  
Oxytocin Receptor ◽  
High Rate ◽  
K Channel ◽  
Obese Women ◽  
Cesarean Sections ◽  
Cholesterol Levels ◽  
Myometrial Contractility ◽  
Lower Expression

: Obesity is a worldwide public health problem, affecting at least one-third of pregnant women. One of the main problems of obesity during pregnancy is the resulting high rate of cesarean section. The leading cause of this higher frequency of cesarean sections in obese women, compared with that in nonobese women, is an altered myometrial function that leads to lower frequency and potency of contractions. In this article, the disruptions of myometrial myocytes were reviewed in obese women during pregnancy that may explain the dysfunctional labor. The myometrium of obese women exhibited lower expression of connexin43, a lower function of the oxytocin receptor, and higher activity of the potassium channels. Adipokines, such as leptin, visfatin, and apelin, whose concentrations are higher in obese women, decreased myometrial contractility, perhaps by inhibiting the myometrial RhoA/ROCK pathway. The characteristically higher cholesterol levels of obese women alter myometrial myocyte cell membranes, especially the caveolae, inhibiting oxytocin receptor function, and increasing the K+ channel activity. All these changes in the myometrial cells or their environment decrease myometrial contractility, at least partially explaining the higher rate of cesarean of sections in obese women.

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