scholarly journals The relationship between contractile force and intracellular [Ca2+] in intact rat cardiac trabeculae.

1995 ◽  
Vol 105 (1) ◽  
pp. 1-19 ◽  
Author(s):  
P H Backx ◽  
W D Gao ◽  
M D Azan-Backx ◽  
E Marban
Keyword(s):  
Steady State ◽  
Cyclopiazonic Acid ◽  
Hill Coefficient ◽  
Atpase Inhibitor ◽  
Relaxation Phase ◽  
Contractile System ◽  
To Come ◽  
State Force ◽  
Relationship Of ◽  
The Relationship

The control of force by [Ca2+] was investigated in rat cardiac trabeculae loaded with fura-2 salt. At sarcomere lengths of 2.1-2.3 microns, the steady state force-[Ca2+]i relationship during tetanization in the presence of ryanodine was half maximally activated at a [Ca2+]i of 0.65 +/- 0.19 microM with a Hill coefficient of 5.2 +/- 1.2 (mean +/- SD, n = 9), and the maximal stress produced at saturating [Ca2+]i equalled 121 +/- 35 mN/mm2 (n = 9). The dependence of steady state force on [Ca2+]i was identical in muscles tetanized in the presence of the Ca(2+)-ATPase inhibitor cyclopiazonic acid (CPA). The force-[Ca2+]i relationship during the relaxation of twitches in the presence of CPA coincided exactly to that measured at steady state during tetani, suggesting that CPA slows the decay rate of [Ca2+]i sufficiently to allow the force to come into a steady state with the [Ca2+]i. In contrast, the relationship of force to [Ca2+]i during the relaxation phase of control twitches was shifted leftward relative to the steady state relationship, establishing that relaxation is limited by the contractile system itself, not by Ca2+ removal from the cytosol. Under control conditions the force-[Ca2+]i relationship, quantified at the time of peak twitch force (i.e., dF/dt = 0), coincided fairly well with steady state measurements in some trabeculae (i.e., three of seven). However, the force-[Ca2+]i relationship at peak force did not correspond to the steady state measurements after the application of 5 mM 2,3-butanedione monoxime (BDM) (to accelerate cross-bridge kinetics) or 100 microM CPA (to slow the relaxation of the [Ca2+]i transient). Therefore, we conclude that the relationship of force to [Ca2+]i during physiological twitch contractions cannot be used to predict the steady state relationship.

Relation of blood flow to VO2, PO2, and PCO2 in dog gastrocnemius muscle

1988 ◽  
Vol 255 (5) ◽  
pp. H1004-H1010 ◽  
Author(s):  
D. E. Mohrman ◽  
R. R. Regal
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Gastrocnemius Muscle ◽  
Muscle Blood Flow ◽  
Carbon Dioxide Tension ◽  
Experimental Conditions ◽  
Muscle Oxygen ◽  
Muscle Oxygen Consumption ◽  
Relationship Of ◽  
The Relationship

We pump-perfused gastrocnemius-plantaris muscle preparations at constant pressure to study the relationship of muscle blood flow (Q) to muscle oxygen consumption (VO2), venous oxygen tension (PVO2), and venous carbon dioxide tension (PVCO2) during steady-state exercise at different rates. Tests were performed under four experimental conditions produced by altering the perfusate blood-gas status with a membrane lung. The consistency of the relationship of Q to other variables was evaluated by statistical analysis of fitted curves. Not one of the above listed variables had the same relationship with Q in all four of the experimental conditions we tested. However, we did find that a consistent relationship existed among Q, PVO2, and PVCO2 in our data. That relationship is well described by the equation (Q-23).[PVO2 - (0.5.PVCO2) - 3] = 105 (when Q is expressed in ml.100 g-1.min-1 and PVO2 and PVCO2 in mmHg). One interpretation of this result is that both PO2 and PCO2 are important variables in the control of blood flow in skeletal muscle the combined influence of which could account for nearly all of the hyperemia response to steady-state muscle exercise.

scholarly journals METODE CONTEXTUAL TEACHING AND LEARNING (CTL) PADA PEMBELAJARAN BE GOING TO VS WILL DI SMK NEGERI 2 MANADO

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Agnes B. B. Mamiasa ◽  
Maya Pinkan Warouw ◽  
Jenny Hilda Pakasi
Keyword(s):  
Teaching And Learning ◽  
Short Form ◽  
Future Tense ◽  
Stop Smoking ◽  
Contextual Understanding ◽  
Contextual Teaching ◽  
To Come ◽  
Relationship Of ◽  
The Relationship ◽  
Time Form

Contextual Teaching and Learning Approach (CTL) is one form of approach that can be said to be capable and very suitable to be a model of appropriate learning when applying the form of material in the classroom. Learning the form of CTL is closely related to the context, atmosphere or circumstances that can be interpreted also as learning related to a particular atmosphere. Talking about the atmosphere has to do with the use of the time form also known as tense. A little interesting about the Simple Future Tense that is raised to the core of learning because of this Tense became one of the important parts in the use of Grammar on learning English where we can express or declare actions in the future. This form uses the word 'will' and 'shall' (short form:’ll) plus infinitive. Besides using the form of 'going to' to be able to declare the time to come and the intention of the speaker to do something, for example I'm going to stop smoking '. CTL's role can make learning more effective and even create a fun and non-boring atmosphere, providing experiences that are closely related to the real world of learners and using a variety of learning resources; and therefore the method on CTL can provide understanding, development of science, the develop of knowledge and contextual understanding of learners about the relationship of subjects with what found learners in everyday life.Keywords : CTL, BE GOING TO vs WILL

Transient responses and continuous behavior of active smooth muscle during controlled stretches

1982 ◽  
Vol 242 (3) ◽  
pp. C146-C158 ◽  
Author(s):  
R. A. Meiss
Keyword(s):  
Steady State ◽  
Smooth Muscles ◽  
Muscle Length ◽  
Initial Slope ◽  
Stretch Rate ◽  
Rate Dependent ◽  
Upward Slope ◽  
Length Changes ◽  
State Force ◽  
The Relationship

Controlled length changes were imposed on mesotubarium superius and ovarian ligament smooth muscles from the reproductive tracts of female rabbits in constant estrus. Stretches of up to 35% of the muscle length were applied during isometric contraction, relaxation, and steady-state force levels. Force was continuously monitored and was plotted as a function of length. During constant velocity stretches there was an initial steep rise in force, a rapid downward deviation from the initial slope, and a long region with a constant upward slope. Stretches made during contraction showed smaller initial rises in force and steeper linear portions than did identical comparison stretches made during relaxation. The value of the slope was independent of the prior developed force, but it did depend on whether the muscle was contracting or relaxing. During contraction and steady-state force levels, the slope was independent of the stretch rate, but it was strongly rate dependent during relaxation. Changes in the stretch rate during stretch caused associated changes in muscle force; the relationship was curvilinear and was exaggerated during relaxation. The findings are placed in the context of a sliding-filament--cross-bridge hypothesis.

Effects of halothane on [Ca2+]i transient, SR Ca2+ content, and force in intact rat heart trabeculae

1998 ◽  
Vol 274 (1) ◽  
pp. H106-H114 ◽  
Author(s):  
Yandong Jiang ◽  
Fred J. Julian
Keyword(s):  
High Dose ◽  
Inotropic Action ◽  
Contractile System ◽  
Intracellular Ca ◽  
Butanedione Monoxime ◽  
High Doses ◽  
Versus Peak ◽  
Relationship Of ◽  
The Relationship ◽  
Ventricular Trabeculae

The goal of this study was to test whether the well-known cardiodepressant effect of halothane is caused mainly by depression of the transient increase in intracellular Ca2+ concentration ([Ca2+]i) during a twitch. Intact rat ventricular trabeculae, paced at 0.5 Hz and 30°C with a bathing extracellular Ca2+ concentration ([Ca2+]o) of 2 mM, were used. The [Ca2+]iwas monitored with the use of fura 2 injected into the myoplasm. The sarcoplasmic reticulum (SR) Ca2+content was estimated with the use of rapid cooling (RC)-induced contracture force and Ca2+release. The relationship of the peak [Ca2+]itransient versus peak twitch force obtained with halothane is intermediate between those obtained with lowered [Ca2+]oand varying doses of 2,3-butanedione monoxime. The data indicate that the negative inotropic action of halothane at low (0.18 mM) dose is mainly achieved by reduction in the Ca2+ sensitivity of the contractile apparatus, whereas, at high dose (0.55 mM), halothane acts both by reducing the [Ca2+]itransient and the Ca2+ sensitivity of the contractile system. At moderate (0.37 mM) dose, the effects were midway between low and high doses. With the use of RC contracture force alone, the reduction of SR Ca2+content caused by halothane is overestimated.

Lennart Heimer: concepts of the ventral striatum and extended amygdala

2008 ◽  
Vol 25 (1) ◽  
pp. E8 ◽  
Author(s):  
W. Jeff Elias ◽  
Dibyendu Kumar Ray ◽  
John A. Jane
Keyword(s):  
Basal Ganglia ◽  
Limbic System ◽  
Basal Forebrain ◽  
Ventral Striatum ◽  
Fiber Tract ◽  
To Come ◽  
Dissection Technique ◽  
Relationship Of ◽  
The Relationship ◽  
Media Formats

Dr. Lennart Heimer, the famous neuroanatomist of Swedish descent, died last year but left a legacy that will impact the neurosciences and potentially psychosurgery for years to come. He developed an anatomical technique for demonstrating the terminal boutons that helped to delineate basal forebrain anatomy. During these studies, he realized the relationship of basal forebrain structures to the limbic system, thus initiating the concept of the ventral striatum and parallel basal ganglia circuitry. Heimer excelled as a teacher as well and honed his brain dissection technique to one of the most effective tools for understanding neuroanatomy. His legendary sessions with neurosurgical residents resulted in his recognition as one of the world’s leading fiber tract dissectors. His gentle, engaging manner has been documented in several media formats.

Negotiating Salafī Islam and the State: The Madkhaliyya in Indonesia

2020 ◽  
Vol 60 (2-3) ◽  
pp. 205-234
Author(s):  
A. Sunarwoto
Keyword(s):  
The State ◽  
Democratic System ◽  
To Come ◽  
Relationship Of ◽  
The Relationship

Abstract The focus of this article is on the Salafiyya-Madkhaliyya in Indonesia, which takes its name from Saudi scholar Rabīʿ al-Madkhalī. After an account of how they emerged and developed in Indonesia, the relationship of the Madkhalīs with the state, which is based on a “fiqh of obedience”, is analyzed. It is argued that, while this legal underpinning necessitates that they give total loyalty to the ruler (walī l-amr, or ūlū l-amr), the Indonesian Madkhalīs are unable to entirely follow this principle. The Madkhalīs have had to come to terms with the fact that Indonesia follows a democratic system, which, in fact, prevents the comprehensive accommodation of their Salafī principles. The resulting ambiguities prove difficult to solve. It is argued here that the negotiation between Madkhalī Salafīs and the Indonesian state is characterized by the constant efforts of the former to tackle those ambiguities.

R439 – Effect of Resistance-Compliance Changes in Fluidic Systems

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P191-P191
Author(s):  
Ryan Dunn ◽  
Rick Odland ◽  
Vivian M Yu ◽  
Paul John Strykowski
Keyword(s):  
Steady State ◽  
Round Window ◽  
University Of Minnesota ◽  
Compensatory Change ◽  
Fluid Systems ◽  
Primary Test ◽  
Relationship Of ◽  
The Relationship ◽  
Mean Time ◽  
Fluid Pathway

Problem Previous work has established the relationship of resistance and compliance in a bench-top model of 2 parallel fluid systems representing endolymph and perilymph. The R-C Product is mathematically proportional to the time to equilibrium. Increasing the resistance to fluid movement in the “endolymph” significantly increased the time to hydrostatic equilibrium between the systems. The current study was designed to test whether a compensatory change in the R-C Product on the “perilymphatic” side would reduce the time to steady state. Methods As previously described, 2 parallel tubular systems with symmetric resistance and compliance members were perturbed by rotating the model from a horizontal, equilibrium condition to an upright, disequilibrium condition. Time to steady state was video recorded in 4 resistance conditions. The primary test was whether increased resistance to flow on the “endolymph” limb would be negated by an equal increase to resistance to flow on the “perilymph” limb. Results All 4 resistance conditions exhibited differences in time to steady state by ANOVA (p = 3.4 × 10E-12). Mean time to a steady state was reduced when a compensatory change in resistance was applied to the “perilymph” limb (1.0 + 1.1 sec) when compared to high resistance in the “endolymph” alone (2.5 + 1.3 sec, p = .01). Conclusion Compensatory changes in the R-C Product can reduce time to equilibrium. Significance Improved treatment of vertigo may be possible by application of principles that can affect resistance (fluid pathway diameter or viscosity) or compliance (stiffness of the oval or round window) of the systems. Support University of Minnesota Biomedical Engineering Institute Otolaryngology Interest Group Fund.

scholarly journals Lymph-migrating, tissue-derived dendritic cells are minor constituents within steady-state lymph nodes

2008 ◽  
Vol 205 (12) ◽  
pp. 2839-2850 ◽  
Author(s):  
Claudia Jakubzick ◽  
Milena Bogunovic ◽  
Anthony J. Bonito ◽  
Emma L. Kuan ◽  
Miriam Merad ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Lymph Node ◽  
Steady State ◽  
Lymph Nodes ◽  
Lymphatic Vessels ◽  
Inflammatory Stimulus ◽  
Major Fraction ◽  
Reporter Mouse ◽  
Relationship Of ◽  
The Relationship

Observations that dendritic cells (DCs) constitutively enter afferent lymphatic vessels in many organs and that DCs in some tissues, such as the lung, turnover rapidly in the steady state have led to the concept that a major fraction of lymph node DCs are derived from migratory DCs that enter the lymph node through upstream afferent lymphatic vessels. We used the lysozyme M–Cre reporter mouse strain to assess the relationship of lymph node and nonlymphoid organ DCs. Our findings challenge the idea that a substantial proportion of lymph node DCs derive from the upstream tissue during homeostasis. Instead, our analysis suggests that nonlymphoid organ DCs comprise a major population of DCs within lymph nodes only after introduction of an inflammatory stimulus.

Sign in / Sign up

Export Citation Format

Share Document