Comment on "Radial and longitudinal motion of the arterial wall: Their relation to pulsatile pressure and flow in the artery".

Most researchers derived the arterial pressure-wave equation by taking the axial blood flow as the major mechanism and assumed the flow motion was governed by the Navier-Stokes equation. However, only realistic hemodynamic theory can help to develop method for future healthcare. Here, we pointed out a different rigorous hemodynamic model that explained many physiological facts.

Examining the response pressure along a fluid-filled elastic tube to comprehend Frank's arterial resonance model.

Frank first proposed the arterial resonance in 1899. Arteries are blood-filled elastic vessels, but resonance phenomena for a fluid-filled elastic tube has not drawn much attention yet. In this study, we measured the pressure along long elastic tubes in response to either a single impulsive water ejection or a periodic water input.

Past, Present, and Future of the Pulse Examination ( mài zhěn).

The pulse examination ( mài zhěn) is a unique diagnostic approach of Traditional Chinese Medicine. The description of pulse examination in the history of Traditional Chinese Medicine is full of amazement and mythology. After researching in hemodynamics and investigating in clinical application for three decades, this article describes the development and the merits and demerits of pulse examination.

Effects of antihypertensive drugs on specific harmonic indices of the pulse waveform in normotensive Wistar Kyoto rats.

We used a self-comparison method and harmonic analysis to compare the blood pressure wave before and after the injection of antihypertensive drugs (atenolol, captopril, and losartan) in normotensive Wistar Kyoto rats. Systolic and diastolic blood pressures decreased significantly after the intraperitoneal injection of drugs. Atenolol significantly reduced all the harmonic proportions of the pulse wave, while captopril and losartan significantly increased the first and fourth harmonic proportions.

Spectral analysis on the microcirculatory laser Doppler signal of the acupuncture effect.

We aim to analyze the frequency content of skin blood flow signals recorded on Hoku following acupuncture stimulation (AS). Each experiment involved recording a 20-minute control-data sequence and two effects data recorded 0-20 and 50-70 minutes after stopping AS, respectively. 4-level Haar-wavelet transform was performed on the measured LDF signals, and periodic oscillations with five characteristic frequency peaks were obtained within the frequency interval: 0.

The benefit of stretching along the artery.

Many rehabilitation exercises involve the stretching of bodies. We point out the necessity of the longitudinal stretching in arteries. The efficiency of an arterial system is closely related to the condition of the transverse vibration of the arterial walls or to the magnitudes of the area oscillation in all blood vessels.

Spectral analysis on the microcirculatory laser Doppler signal at the acupuncture point.

We aimed to characterize the frequency spectra of skin blood flow signals simultaneously recorded at Hoku, an important acupoint in oriental medicine, and two nearby nonacupoints to understand the underlying physiological mechanism of acupuncture points. ECG and laser Doppler flowmetry signals were measured simultaneously. A four-level Haar wavelet transform was applied to the measured 20-minute LDF signals, and periodic oscillations with five characteristic frequency peaks were obtained within the following frequency bands: 0.

Similarity between coffee effects and qi-stimulating events.

Aims: Previously, we found that qi-stimulating events exerted similar frequency-specific effects on the blood pressure pulse spectrum. Because coffee and qi induce similar stimulatory psychological responses, we aimed to determine whether they would induce similar pulse effects. Such a relationship would suggest a close linkage between the physiologic mechanisms underlying the psychostimulatory responses and vascular effects of coffee and qi.

Spectral analysis of the microcirculatory laser Doppler signal at the Hoku acupuncture point.

We aimed to characterize the frequency spectra of skin blood flow signals recorded at Hoku, an important acupuncture point (acupoint) in oriental medicine. Electrocardiogram (ECG) and laser Doppler flowmetry signals were measured simultaneously in 31 trials on seven volunteers aged 21-27 years. A four-level Haar wavelet transform was applied to the measured 20 min laser Doppler flowmetry (LDF) signals, and periodic oscillations with five characteristic frequency peaks were obtained within the following frequency bands: 0.

Connection between RR-interval length and the pulsatile microcirculatory flow.

The present study used laser Doppler flowmetry (LDF) to investigate the connection between skin microcirculatory flow and the length of the RR interval (LRR). Local heating was performed on healthy volunteers to further elucidate its effect on LDF index. ECG and LDF signals were measured in 102 trials on seven volunteers.

Evaluation of stationarity of laser Doppler signal in the pulse-based synchronized-averaging analysis.

Pulse parameters calculated from the LDF waveform based on time-domain synchronized averaging analysis were shown to be able to discriminate the difference in microvascular resistance, however its applicability depends seriously on the assumption of signal stationarity. In this study, our aim is to investigate the effect of pulse number, which may destroy the signal stationarity, on the pulse LDF parameters. The study presented here has established the criteria for pulse number to achieve the signal stationarity so that the microcirculatory discriminability of the pulse-based time-averaging analysis on LDF signal can be improved.

Study on the microcirculatory blood velocity of acupoint monitored by laser Doppler signal.

Meridian system composed of acupoints is the most fundamental concept to build oriental medicine. In this study, we employ LDF measurement to compare the microcirculatory blood velocity of acupuncture point and its surrounding tissues. Measurements were performed around an important acupoint in oriental medicine, Hoh-Ku (Li4, on the hand), in healthy volunteers.

Microcirculatory characteristics of acupuncture points obtained by laser Doppler flowmetry.

Acupuncture points (acupoints) form part of the meridian system that constitutes the most fundamental concept in oriental medicine, but their physiological basis has not been clarified. In this study we employed laser Doppler flowmetry (LDF) to extract the microcirculatory characteristics of acupoints and their surrounding tissues, and we interpreted the results from the viewpoint of microcirculatory physiology. Three groups of measurements were performed focusing on the following two important acupoints in oriental medicine in healthy volunteers (n = 13 for group A and n = 9 for groups B and C, respectively): Hoh-Ku (Li4, on the hand) and Ching-Ku (B64, on the foot).

Effects of angiotensin II on flux rise time in rats (a time index of laser Doppler flowmetry) and its relation with microvascular structures.

Laser Doppler flowmetry (LDF) is a popular method for monitoring the microcirculation, but it does not provide absolute measurements on local area with small size microvessels. Instead, the mean flux response is generally compared between before and after stimulus. In this study, we proposed a new dimension for comparing the LDF signals.

One important area gradient force has been omitted in the Moens and Korteweg's Equation.

Pulse wave velocity is mostly related to the young's modulus by the Moens and Korteweg's formula. In deriving this formula, the wall's effect on the blood was ignored at the first step and the pressure gradient was considered as the only driving force in the axial flow of the blood. The local area gradient was assumed to be zero.

Organ-specific ligation-induced changes in harmonic components of the pulse spectrum and regional vasoconstrictor selectivity in Wistar rats.

It has been shown previously that the amplitudes of the harmonic components of the pulse spectrum vary in specific patterns when the arteries leading to different organs are ligated, with the variations in the harmonics being linearly additive. Since ligation can be regarded as a vast increase in organ resistance, the present study examined the potential of using these ligation-induced variations in the pulse spectrum as reference parameters for an increase in vascular resistance and for regional vasoconstrictor selectivity. A vasoconstrictor, either arginine vasopressin (AVP) or angiotensin II (Ang II), was infused into anaesthetized Wistar rats via the femoral vein for 1 h.

Three-block electrical model of renal impedance.

In this study, we measured the characteristic renal impedance profiles of Wistar rats and simulated the profiles using an electrical model with three series connected Windkessel blocks containing inductance. It is expected that a complete renal impedance profile ought to provide better physical properties information and have more diagnostic power than the pulsatility (PI) and resistive indices (RI) as a result of frequency dependency. A characteristic peak value at the third harmonic on the renal impedance amplitude curve was observed and the phase curve decreased with increasing harmonic numbers.

The eccentric position of the heart in the mammalian body and optimal energy transfer in single tube models.

Many phenomena cannot be explained by traditional haemodynamics models. For example, the hearts of all mammals are neither at one end of the circulatory system nor at the geometric centre. Based on a new circulation model, we report that if the heart is located at either of these two positions, the energy saving rule will be violated.

Pressure pulse velocity is related to the longitudinal elastic properties of the artery.

It is known that arteries in their natural position are always subject to a longitudinal stress. However, the effect of this strong longitudinal tension has seldom been addressed. In this paper, we point out that the traditional pulse wave velocity formulae considering only the circumferential elasticity fail to include all the important energies.