タウはイソボリュメトリックリラクゼーションのプレロード独立度量ですか?
S K Varma1, R M Owen, M L Smucker
1Department of Internal Medicine, University of Virginia School of Medicine, Charlottesville.
Circulation
|December 1, 1989
まとめ
心筋タウの延長は心臓疾患で観察されていますが,その原因は不明です. この研究では,健康な個体でのプレロードの減少はタウを変化させなかったことが判明し,これは単に心臓の負荷ではなく,異常な生理を反映していることを示唆しています.
科学分野:
- 心臓病学 心臓病学
- 生理学 生理学とは
背景:
- 心筋タウの延長は,様々な心筋疾患において知られている発見である.
- 長く続くタウの原因は不明であり,それが異常な心筋の生理学を反映しているか,または疾患に関連する過度の負荷を反映しているかどうかについては議論が続いている.
研究 の 目的:
- 健康な個体における心筋タウに対するプレロードの単一の減少の影響を調査する.
- 長く続くタウが異常な心筋生理学的状態を示すのか,または心筋の労働負荷の増加の結果であるかを判断する.
主な方法:
- 6人の健康な患者は,反射変化が起こる前に,プリロードの孤立した減少を誘発するために下静脈閉塞を受けた.
- 心臓の収縮は,コンピュータベースのデジタル化ルーチンを使用して分析されました.
- 筋動脈のタウは,前負荷減算前と後の対数式 (TL),微分式 (TD),ミルスキー式 (T1/2) を用いて計算された.
主要な成果:
- 下腔静脈の閉塞は,左心室内静脈圧や心拍数を大きく変化させることなく,左心室内静脈圧の低減に成功しました.
- プレロードの単離的な減少の後,タウ (TL,TD,またはT1/2) の有意な変化は観察されなかった.
- イソヴォルメトリック・リラクゼーションによるエクストラポレーションされたベースライン圧力は変わらなかった.
結論:
- 健康な個体におけるプレロードの孤立した減少は,心筋のタウを変化させない.
- この発見は,長時間続くタウが,単に心筋負荷の増加の結果というより,異常な心筋生理学を表している可能性があることを示唆している.
関連する概念動画
Torque
Torque is an important quantity for describing the dynamics of a rotating rigid body. We see the application of torque in many ways in the world, such as when pressing the accelerator in a car, which causes the engine to apply additional torque on the drivetrain. Here, we define torque and provide a framework to create an equation to calculate torque for a rigid body with fixed-axis rotation.
Torque can be considered as the rotational counterpart to force. Since forces change the translational...
Torque can be considered as the rotational counterpart to force. Since forces change the translational...
Torsional Pendulum
A torsional pendulum involves the oscillation of a rigid body in which the restoring force is provided by the torsion in the string from which the rigid body is suspended. Ideally, the string should be massless; practically, its mass is much smaller than the rigid body's mass and is neglected.
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played by the...
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played by the...
Kendall's Tau Test
Kendall's tau test, also known as the Kendall rank coefficient test, is a nonparametric method for assessing association between two variables. This test is particularly useful for identifying significant correlations when the distributions of the sample and population are unknown. Developed in 1938 by the British statistician Sir Maurice George Kendall, the tau coefficient (denoted as τ) serves as a rank correlation coefficient, with values ranging from -1 to +1.
A τ value of +1 indicates that...
A τ value of +1 indicates that...
Torque Free Motion
The torque-free motion refers to the movement of a rigid body in space when no external torques are acting upon it. This type of motion can be observed in environments where there are no external forces or frictions, like in outer space. For example, a rotation of Mars in space is a torque-free motion. Mars is an axisymmetric object, meaning it has an axis of symmetry along which it rotates, designated as the z-axis. The rotating frame of reference is defined such that the center of mass of...
Shearing Stress
Shearing stress, denoted by the Greek letter tau (τ), is stress caused by forces acting transversely on an object. These forces create internal ones within the entity in the plane where the external forces are applied. The resultant of these internal forces is the shear in the section.
The average shearing stress can be calculated by dividing the shear by the area of the cross-section.
The average shearing stress can be calculated by dividing the shear by the area of the cross-section.
Torsion in Vector Calculus
A toy train ascending a winding track that curves and tilts offers an intuitive view of torsion, a key geometric concept in the study of space curves. While curvature measures how sharply a path bends, torsion captures how the path twists out of the plane of bending. This twisting behavior is crucial in understanding three-dimensional motion and is precisely described using the Frenet–Serret framework.At each point along a space curve, the Frenet–Serret frame consists of three orthogonal unit...


